/Users/andrea/_magisterarbeit/korpus/clean/trainkorpus/29/file_186.html NN ----------------------------------------- : Administration NP Resources NPS Telecom NP Terms NNS FAQ's NP Procedures NNS Utilities NP Knowledge NN Base NP Telecommunications NP Terms NNS Click NP the DT initial JJ letter NN of IN the DT term NN you PP want VVP to TO look VV up RP A DT B NP C NP D NP E NP F NP G NP H NP I NP J NP K NP L NP M NP N NP O NP P NN Q NP R NP S NP T NN U NP V NN W NP X NP Y NP Z NP 0 CD 2 CD B NP 1 CD Q NP . SENT Two CD Binary NN One CD Quarternary NN . SENT An DT ISDN NP digital JJ subscriber NN loop NN encoding VVG technique NN adapted VVN by IN ANSI NP for IN use NN in IN the DT U NP . SENT S NP . SENT This DT technique NN encodes VVZ a DT two CD bit NN dibit NN group NN using VVG a DT four CD state NN digital JJ line NN code NN two CD amplitude NN levels NNS in IN both DT polarities NNS . SENT The DT result NN is VBZ to TO half PDT the DT actual JJ transition NN rate NN of IN the DT digital JJ loop NN . SENT The DT 2 CD B NN 1 CD Q NP plan NN also RB calls VVZ for IN substituting VVG digital JJ echo NN cancellation NN for IN time NN compression NN multiplexing VVG . SENT 2 CD B NP D NP . SENT Basic JJ ISDN NP access NN . SENT 23 CD B NP D NP . SENT Primary JJ ISDN NP access NN in IN North NP America NP based VVN on IN a DT 1 CD . SENT 544 CD Mb NN s VVZ 24 CD channel NN DS NP 1 CD standard NN . SENT 30 CD B NP 2 CD D NP . SENT Primary JJ ISDN NP access NN in IN nations NNS using VVG the DT CEPT NN digital JJ carrier NN system NN . SENT 802 CD . SENT X SYM . SENT A DT set NN of IN LAN NP and CC MAN NN standards NNS developed VVN by IN IEEE NP . SENT A DT Back RB to TO Top JJ AD NN Analog NP to TO Digital NP converter NN Advanced NP Intelligent JJ Network NP AIN NN A DT term NN used VVN to TO refer VV to TO the DT integration NN of IN ISDN NP and CC Cellular NP Radio NP into IN a DT Personal NP Communications NPS System NP PCS NP . SENT ISDN NP provides VVZ the DT ability NN to TO assign VV a DT phone NN to TO a DT person NN as RB opposed VVN to TO a DT line NN termination NN . SENT When WRB the DT phone NN is VBZ used VVN it PP establishes VVZ a DT session NN with IN the DT attached VVN CO NP switch NN , , and CC through IN the DT services NNS of IN Signaling VVG System NP 7 CD , , all DT billing NN is VBZ returned VVN to TO the DT proper JJ account NN . SENT By IN adding VVG wireless NN interfaces NNS to TO ISDN NP a DT personal JJ cellular JJ telephone NN could MD be VB attached VVN to TO the DT global JJ ISDN NP from IN any DT worldwide JJ location NN . SENT Problems NNS . SENT the DT lack NN of IN standardization NN of IN the DT radio NN interface NN frequencies NNS and CC modulation NN and CC the DT less JJR than IN uniform JJ deployment NN of IN ISDN NP . SENT Address NN In IN data NN communications NNS , , a DT sequence NN of IN bits NNS or CC characters NNS , , that WDT identifies VVZ a DT network NN station NN , , user NN , , or CC application NN . SENT used VVN mainly RB for IN routing VVG purposes NNS . SENT In IN telephony NN , , the DT number NN entered VVN by IN the DT caller NN that WDT identifies VVZ the DT party NN called VVD . SENT CCITT NP X NP . SENT 400 CD seeks VVZ to TO develop VV a DT world NN wide JJ addressing VVG system NN for IN data NN communications NNS . SENT ADPCM NP Adaptive JJ Differential NN Pulse NP Code NP Modulation NN . SENT An DT encoding VVG technique NN , , standardized JJ by IN the DT CCITT NP , , that WDT allows VVZ a DT 4 CD kHz NN voice NN channel NN to TO be VB carried VVN within IN a DT 32 CD Kb NP s PP digital JJ channel NN . SENT The DT technique NN uses VVZ 3 CD or CC 4 CD bits NNS to TO describe VV the DT difference NN between IN two CD samples NNS , , taken VVN at IN a DT sampling VVG rate NN of IN 8 CD , , 000 CD times NNS a DT second NN . SENT A DT Law NN A DT companding JJ algorithm NN used VVN as IN the DT CEPT NN standard NN for IN DS NP 0 CD PCM NP speech NN companding NN . SENT Alternate JJ routing VVG A DT feature NN of IN network NN switches NNS , , DACS NP and CC PBXs NP , , where WRB a DT call NN is VBZ completed VVN over IN secondary JJ circuit NN routes NNS when WRB primary JJ routes NNS are VBP unavailable JJ . SENT AMI NN Alternate JJ Mark NP Inversion NN . SENT Used VVN in IN the DT DS NP 1 CD digital JJ signal NN , , where WRB the DT first JJ mark NN 1 CD is VBZ a DT positive JJ voltage NN and CC the DT next JJ mark NN 1 CD is VBZ a DT negative JJ voltage NN . SENT See VV bipolar JJ . SENT Often RB used VVN to TO refer VV to TO a DT DS NP 1 CD with IN robbed VVN bit NN signaling VVG and CC without IN B NP 8 CD ZS NP coding VVG . SENT Amplifier NN Any DT electronic JJ component NN that WDT boosts VVZ the DT strength NN or CC amplitude NN of IN a DT transmitted JJ analog JJ signal NN . SENT functionally RB equivalent JJ to TO a DT repeater NN in IN digital JJ transmissions NNS . SENT Amplitude NN The DT magnitude NN of IN variation NN in IN an DT alternating VVG voltage NN or CC current JJ from IN the DT 0 CD point NN . SENT The DT term NN is VBZ used VVN to TO refer VV to TO the DT level NN of IN an DT audio JJ or CC other JJ signal NN . SENT The DT adjectives NNS peak NN , , rms NNS , , maximum JJ etc NN . SENT should MD be VB used VVN to TO provide VV a DT more RBR accurate JJ description NN of IN the DT signal NN value NN . SENT Advanced NP Mobile NP Phone NN Service NP AMPS NNS The DT current JJ analog NN technology NN used VVN for IN North NP American NP cellular JJ telephone NN service NN . SENT Developed VVN in IN the DT 1970 CD s PP and CC deployed VVN about IN 1984 CD , , AMPS NNS uses VVZ a DT modem NN driven VVN digital JJ interface NN for IN the DT setup NN and CC control NN of IN 30 CD kHz NN analog JJ voice NN channels NNS . SENT Analog NN In IN communications NNS , , transmission NN employing VVG variable JJ and CC continuous JJ waveforms NNS to TO represent VV information NN values NNS , , where WRB interpretation NN by IN the DT receiver NN is VBZ an DT estimated JJ approximation NN quantization NN of IN the DT encoded VVN value NN . SENT compare VV with IN digital JJ . SENT ANSI NP American NP National NP Standards NPS Institute NP . SENT A DT non JJ profit NN organization NN that WDT performs VVZ the DT administrative JJ functions NNS of IN the DT standardization NN process NN . SENT Antenna NN Gain NN The DT gain NN of IN a DT radio NN antenna NN expressed VVN in IN dbi NP referenced VVD to TO a DT theoretical JJ perfect JJ dipole NN antenna NN . SENT In IN microwave NN radio NN the DT gain NN of IN a DT parabolic JJ antenna NN is VBZ calculated VVN by IN the DT formula NN . SENT G NP db NP 20 CD logF NN MHz NN 20 CD logD NN ft NP 52 CD . SENT 6 CD . SENT Application NN Layer NP Layer NP 7 CD of IN the DT OSI NP model NN , , defines VVZ the DT final JJ user NN of IN the DT data NN communications NNS process NN , , normally RB a DT data NN communications NN program NN such JJ as IN VTAM NP IBM NP , , or CC Network NP Management NP programs NNS . SENT ASCII NP American NP National NP Standard NP Code NP for IN Information NP Interchange VV . SENT A DT standard JJ seven CD bit NN eight CD bits NNS , , with IN parity NN character NN code NN used VVN for IN data NN communications NNS and CC data NNS processing NN . SENT ARPA NP ARPAnet NP Advanced NP Research NP Projects NPS Agency NP . SENT Part NN of IN the DT Department NP of IN Defense NP . SENT Developer NN , , through IN project NN coordination NN and CC funding NN , , of IN most RBS modern JJ data NN communications NNS technology NN , , including VVG HDLC NP , , Packet NN Switching NP , , and CC TCP NN IP NP . SENT Established VVN the DT ARPAnet NP , , a DT network NN of IN major JJ universities NNS , , defense NN contractors NNS and CC government NN agencies NNS , , that WDT was VBD used VVN to TO test VV and CC improve VV TCP NN IP NP . SENT Asynchronous JJ In IN data NN communications NNS , , transmission NN that WDT is VBZ not RB related VVN to TO a DT specific JJ timing NN of IN the DT transmission NN facility NN . SENT Data NP transmission NN characterized VVN by IN individual JJ characters NNS , , or CC bytes NNS , , encapsulated VVN with IN start NN and CC stop NN bits NNS , , from IN which WDT a DT receiver NN derives VVZ the DT necessary JJ timing NN . SENT Also RB known VVN as IN start NN stop NN transmission NN . SENT In IN high JJ speed NN digital JJ transmission NN , , a DT DS NP 1 CD with IN framing NN bit NN is VBZ said VVN to TO be VB synchronous JJ while IN the DT multiplex JJ bit NN interleaved VVN DS NP 2 CD or CC DS NP 3 CD s PP ignals NNS are VBP said VVN to TO be VB asynchronous JJ . SENT ATM NN Asynchronous JJ Transfer NN Mode NP . SENT A DT CCITT NP term NN for IN Broadband NP ISDN NP technology NN using VVG cell NN relay NN techniques NNS . SENT Multiplexing VVG and CC switching VVG is VBZ accomplished VVN with IN 53 CD byte NN cells NNS each DT containing VVG a DT channel NN identifier NN . SENT ATM NN Adaptation NN Layer NP AAL NP A DT physical JJ sub NN layer NN of IN the DT ATM NN standards NNS . SENT The DT AAL NP prepares VVZ data NNS for IN placement NN in IN cells NNS . SENT AAL NP has VHZ two CD sub NN layers NNS . SENT The DT Convergence NN sub NN layer NN forms VVZ a DT large JJ identifiable JJ frame NN . SENT The DT segmentation NN reassembly NN sub NN layer NN divides VVZ the DT convergence NN frame NN into IN 44 CD 47 CD byte NN segments NNS . SENT ATM NN Layer NP A DT physical JJ sub NN layer NN of IN the DT ATM NN standards NNS that WDT places VVZ segments NNS formed VVN in IN the DT ATM NN Adaptation NN Layer NP AAL NP into IN cells NNS . SENT The DT ATM NN layer NN manages VVZ the DT cell NN overhead NN . SENT Attenuation NN Reduction NN of IN loss NN of IN signal NN strength NN , , measured VVN in IN decibels NNS . SENT opposite JJ of IN gain NN . SENT Auto NN answer NN Automatic JJ answering NN . SENT capability NN of IN a DT terminal NN , , modem NN , , computer NN , , or CC similar JJ device NN to TO respond VV to TO an DT incoming JJ call NN on IN a DT dial NN up IN telephone NN line NN , , and CC to TO establish VV a DT data NN connection NN with IN a DT remote JJ device NN , , without IN operator NN intervention NN . SENT unattended JJ operation NN for IN incoming JJ dial NN up IN calls NNS . SENT Autodial JJ Automatic JJ dialing NN . SENT capability NN of IN a DT terminal NN , , modem NN , , computer NN , , or CC similar JJ device NN to TO place VV a DT call NN over IN the DT switched VVN telephone NN network NN , , and CC establish VV a DT connection NN , , without IN operator NN intervention NN . SENT also RB , , autocall NP . SENT Autodin NP Automatic NP Digital NP Network NP . SENT part NN of IN U NP . SENT S NP . SENT Department NP of IN Defense NP . SENT Automatic JJ Repeat NN Request NN ARQ NP A NP data NN communications NNS term NN referring VVG to TO the DT automatic JJ request NN for IN retransmission NN of IN data NNS found VVN by IN the DT error NN detection NN system NN . SENT Automatic NP Route NP Selection NN ARS NN The DT capability NN of IN a DT switch NN , , typically RB a DT private JJ branch NN exchange NN PBX NP , , to TO automatically RB determine VV an DT optimal JJ route NN establishing VVG a DT circuit NN . SENT also RB called VVD least JJS cost NN routing VVG LCR NP . SENT B SYM Back RB to TO Top JJ B NP 8 CD ZS NP Binary NN 8 CD Zero NP Substitution NN . SENT A DT technique NN used VVN with IN DS NP 1 CD signals NNS in IN order NN to TO maintain VV ones NNS density NN , , where WRB a DT special JJ code NN is VBZ substituted VVN for IN eight CD consecutive JJ zeros NNS and CC marked VVD by IN two CD bipolar JJ violations NNS . SENT The DT use NN of IN B NP 8 CD ZS NP allows VVZ the DT use NN of IN a DT full JJ 64 CD kb NN s PP DS NP 0 CD for IN data NN transmission NN . SENT Not RB compatible JJ with IN older JJR AMI NN equipment NN . SENT Referred VVN to TO Bipolar JJ 8 CD Zero NP Substitution NN by IN early JJ AT IN T NN ref NN . SENT Balanced JJ to TO ground VV An DT implied VVN three CD wire NN circuit NN , , where WRB the DT impedance NN to TO ground VV on IN one CD wire NN equals VVZ the DT impedance NN to TO ground VV on IN the DT other JJ wire NN . SENT compare VV with IN unbalanced VVN to TO ground VV two CD wire NN circuit NN . SENT A DT preferable JJ condition NN for IN data NN transmission NN . SENT Standardized JJ by IN EIA NP RS NP 422 CD . SENT Balun NN Balanced VVN unbalanced JJ , , refers VVZ to TO an DT impedance NN matching VVG device NN used VVN to TO connect VV balanced JJ twisted JJ pair NN cabling VVG with IN unbalanced JJ coaxial JJ cable NN . SENT Bandwidth NN The DT difference NN , , expressed VVN in IN Hertz NP Hz NP , , between IN the DT highest JJS and CC lowest JJS frequencies NNS of IN a DT transmission NN channel NN . SENT The DT term NN is VBZ also RB commonly RB used VVN to TO refer VV to TO the DT line NN rate NN of IN a DT data NNS channel VVP in IN bits NNS per IN second JJ . SENT The DT information NN carrying VVG capacity NN of IN a DT communications NNS channel NN is VBZ directly RB proportional JJ to TO its PP$ bandwidth NN . SENT Baseband NP a DT In IN Frequency NN Division NN Modulation NN FDM NP baseband NN describes VVZ the DT band NN of IN frequencies NNS occupied VVN by IN the DT composite NN modulated VVD analog JJ carrier NN frequency NN . SENT b SYM In IN LAN NP technology NN , , baseband NN refers VVZ to TO using VVG Time NP Division NP Multiplex JJ TDM NP transmission NN on IN a DT single JJ channel NN versus CC Frequency NN Division NN Multiplex JJ FDM NP broadband NN multi NNS channel VVP transmission NN . SENT Basic NP Access NP In IN ISDN NP , , basic JJ access NN consists VVZ of IN two CD 64 CD kb NN s PP Bearer NN channels NNS and CC one CD 16 CD kb NN s PP D NP channel NN 2 CD B NP D NP . SENT This DT is VBZ the DT minimum JJ ISDN NP service NN available JJ . SENT BASIC JJ Language NP Beginners NNS All DT Symbolic JJ Instruction NN Code NP . SENT A DT programming NN high JJ level NN language NN . SENT Baud NN A DT measurement NN of IN the DT signaling VVG speed NN of IN a DT data NN transmission NN device NN . SENT equivalent JJ to TO the DT maximum JJ number NN of IN signaling VVG elements NNS , , or CC symbols NNS , , per IN second JJ that WDT are VBP generated VVN . SENT may MD be VB different JJ from IN bit NN rate NN , , especially RB at IN higher JJR speeds NNS , , as IN several JJ bits NNS may MD be VB encoded VVN per IN symbol NN , , or CC baud NN , , with IN advanced JJ encoding VVG techniques NNS such JJ as IN phase NN shift NN keying VVG . SENT Baudot NP Code NP The DT original JJ teletype VV data NN transmission NN code NN . SENT Implemented VVN about IN 1870 CD it PP was VBD composed VVN of IN marks NNS and CC spaces NNS so RB named VVN because IN of IN the DT practice NN of IN punching VVG marks NNS into IN a DT paper NN tape NN . SENT Baudot NP is VBZ using VVG five CD bits NNS for IN character NN representation NN , , one CD of IN which WDT is VBZ a DT letters NNS figures NNS shift VVP . SENT Only RB upper JJ case NN letters NNS are VBP used VVN . SENT Transmission NP was VBD asynchronous JJ and CC originally RB accomplished VVN by IN reversing VVG the DT polarity NN of IN the DT DC NP telegraph NN line NN . SENT By IN the DT 1920 CD s PP FSK NP modulation NN was VBD used VVN . SENT In IN Telegraphy NN , , Baudot NP code NN was VBD replaced VVN by IN ASCII NP in IN the DT late JJ 1960 CD s PP . SENT BCC NP Block NP check NN character NN . SENT control NN character NN appended VVN to TO blocks NNS are VBP character NN oriented JJ protocols NNS that WDT are VBP used VVN for IN determining VVG if IN the DT block NN was VBD received VVN in IN error NN . SENT They PP are VBP used VVN in IN longitudinal JJ and CC cyclic JJ redundancy NN checking NN . SENT The DT BCC NP was VBD developed VVN for IN early RB teletype VV and CC IBM NP Bisync NP character NN transmission NN . SENT BER NP See NP Bit NN Error NN Rate NP Bellcore NP Bell NP Communications NPS Research NP . SENT an DT organization NN established VVN by IN the DT AT IN T NN divestiture NN , , representing VVG and CC funded VVN by IN the DT Regional NP Bell NP Carriers NPS RBOCs NP , , for IN the DT purposes NNS of IN establishing VVG telephone NN network NN standards NNS , , training NN materials NNS and CC quality NN procedures NNS . SENT Bend VV radius NN Radius NN of IN curvature NN that IN a DT fiber NN can MD bend VV signal NN loss NN . SENT BERTS NPS Basic NP Exchange NP Radio NP Telecommunications NPS Service NP . SENT A DT system NN developed VVN in IN the DT 1980 CD s NN to TO provide VV wireless NN access NN to TO a DT standard JJ local JJ loop NN . SENT BERTS NPS uses VVZ TDMA NP on IN multiple JJ FDMA NP channels NNS in IN the DT 150 CD 450 CD MHz NN and CC 800 CD MHz NN range NN . SENT Voice NN Channels NNS are VBP 16 CD Kb NP s PP ADPCM NP with IN DSI NP . SENT Spectrum NN efficiency NN is VBZ 80 CD channels NNS per IN MHz NN . SENT Typical JJ applications NNS include VVP rural JJ telephone NN service NN , , rapidly RB expanding VVG isolated JJ subdivisions NNS and CC emergency NN restoration NN . SENT Wire NN line NN T NN 1 CD service NN from IN a DT central JJ office NN is VBZ extended VVN to TO a DT transmitter NN site NN . SENT A DT receiver NN is VBZ installed VVN as IN network NN equipment NN and CC connected VVN as IN a DT subscriber NN loop NN to TO the DT protector NN block NN . SENT BERTS NPS is VBZ FCC NP approved VVD and CC US NP West NP has VHZ undergone VVN field NN trials NNS to TO incorporate VV this DT technology NN in IN a DT metropolitan JJ PCN NN . SENT This DT test NN uses VVZ a DT cellular JJ 450 CD MHz NN concept NN connected VVN to TO a DT standard JJ digital JJ loop NN carrier NN DLC NP . SENT This DT provides VVZ loop NN access NN with IN a DT digital JJ cellular JJ instrument NN . SENT Also RB called VVN BEXR NP , , Basic NP Exchange NP Radio NP Bipolar JJ a DT In IN digital JJ transmission NN , , an DT electrical JJ line NN signaling VVG method NN in IN which WDT the DT mark NN value NN alternates VVZ between IN positive JJ and CC negative JJ polarities NNS . SENT b SYM In IN semiconductors NNS , , a DT design NN based VVN on IN the DT flow NN of IN current JJ across IN a DT PN NP junction NN . SENT BISDN NP Broadband NP ISDN NP . SENT Refers VVZ to TO ISDN NP services NNS offered VVN at IN rates NNS higher JJR than IN the DT Primary JJ access NN rate NN 23 CD B NP D NP of IN 1 CD . SENT 544 NP MB NP s PP or CC 2 CD . SENT 048 CD Mb NN s PP . SENT Proposed VVN broadband JJ ISDN NP service NN is VBZ defined VVN by IN CCITT NP as RB switched VVD services NNS from IN 34 CD Mb NN s PP to TO 680 CD Mb NN s PP using VVG cell NN relay NN technology NN . SENT Channels NNS are VBP designated VVN as IN H NP channels NNS . SENT Bisync NP Binary JJ synchronous JJ communications NNS BSC NP . SENT Character NN oriented JJ data NN communications NNS protocol NN developed VVN by IN IBM NP . SENT oriented VVN toward IN half DT duplex NN link NN operation NN . SENT still RB widely RB employed VVN , , though RB replaced VVN in IN current JJ IBM NP data NNS communications NNS products NNS by IN the DT bit NN oriented VVN synchronous JJ data NNS link NN control NN SDLC NP . SENT Bit NN A DT binary JJ digit NN , , the DT representation NN of IN a DT signal NN , , wave NN , , or CC state NN , , as IN either RB a DT binary JJ zero NN or CC a DT one NN . SENT Bit NN error NN The DT case NN where WRB the DT value NN of IN an DT encoded VVN bit NN is VBZ changed VVN in IN transmission NN , , and CC interpreted VVD incorrectly RB by IN the DT receiver NN . SENT Bit NN Error NN Rate NP BER NP The DT percentage NN of IN received VVN bits NNS that WDT are VBP in IN error NN , , relative JJ to TO a DT specific JJ amount NN of IN bits NNS received VVD . SENT usually RB expressed VVN as IN a DT number NN referenced VVD to TO a DT power NN of IN 10 CD . SENT e SYM . SENT g NN . SENT 1 CD in IN 105 CD . SENT Bit NN Oriented JJ Describing VVG a DT communications NNS protocol NN or CC transmission NN procedure NN where WRB control NN information NN is VBZ encoded VVN in IN fields NNS of IN one CD or CC more JJR bits NNS . SENT oriented VVN toward IN full JJ duplex NN link NN operation NN . SENT uses VVZ less JJR overhead NN , , and CC is VBZ therefore RB more RBR efficient JJ than IN character NN byte NN oriented JJ protocols NNS Bit NN stuffing VVG A DT process NN of IN adding VVG bits NNS marks NNS to TO a DT data NN stream NN . SENT Used VVN in IN bit NN oriented JJ data NNS link VVP protocols NNS in IN order NN to TO prevent VV the DT flag NN sequence NN 01111110 CD from IN entering VVG the DT data NN block NN . SENT Also RB used VVN to TO balance VV the DT input NN output NN flow NN in IN asynchronous JJ data NNS communications NNS buffers VVZ DS NP 2 CD DS NP 3 CD . SENT Bit NN s NN b SYM s PP Bits NNS per IN second JJ . SENT basic JJ unit NN of IN measure NN for IN serial JJ data NNS transmission NN capacity NN . SENT kb NN s PP or CC kilobit NN s PP , , for IN thousands NNS of IN bits NNS per IN second JJ . SENT Mb NP s PP or CC megabit NP s PP , , for IN millions NNS of IN bits NNS per IN second JJ . SENT Gb VV s PP or CC gigabit VV s PP for IN billions NNS of IN bits NNS per IN second JJ . SENT Tb NP s PP or CC terabit VV s PP for IN trillions NNS of IN bits NNS per IN second JJ . SENT Block VV A DT quantity NN of IN transmitted JJ information NN regarded VVN as IN a DT discrete JJ entity NN and CC containing VVG its PP$ own JJ starting VVG and CC ending VVG control NN delimiters NNS , , usually RB self NN contained VVD control NN , , routing VVG , , and CC error NN checking NN . SENT Block NN assembly NN is VBZ normally RB considered VVN a DT data NNS link VVP OSI NP level NN 2 CD function NN but CC may MD be VB accomplished VVN by IN level NN 3 CD or CC 4 CD . SENT Blocking VVG The DT inability NN of IN a DT network NN , , switch VV , , or CC access NN node NN to TO grant VV service NN to TO a DT requesting VVG user NN due JJ to TO the DT unavailability NN of IN a DT transmission NN channel NN . SENT Boundary NN node NN In IN IBMs NP SNA NP , , a DT subarea NN node NN that WDT can MD provide VV certain JJ protocol NN support NN for IN adjacent JJ subarea NN nodes NNS , , including VVG transforming VVG network NN addresses NNS to TO local JJ addresses NNS , , and CC visa NN versa FW , , and CC performing VVG session NN level NN sequencing VVG and CC flow NN control NN for IN less JJR intelligent JJ peripheral JJ nodes NNS . SENT Bridge NP A NP device NN used VVD to TO connect VV networks NNS with IN similar JJ OSI NP level NN 1 CD 2 CD protocols NNS . SENT Example NN . SENT connecting VVG two CD IEEE NP 802 CD . SENT 5 CD token JJ ring NN networks NNS . SENT Broadband NN Describing VVG transmission NN equipment NN and CC media NNS that WDT can MD support VV a DT wide JJ range NN of IN electromagnetic JJ frequencies NNS . SENT typically RB the DT technology NN of IN CATV NP transmission NN , , as RB applied VVN to TO data NN communications NNS , , that WDT employs VVZ coaxial JJ cable NN as IN the DT transmission NN medium NN and CC radio NN frequency NN carrier NN signals NNS in IN the DT 50 CD to TO 500 CD MHz NN range NN . SENT any DT communications NN channel NN having VHG a DT bandwidth NN greater JJR than IN a DT voice NN grade NN telecommunications NN channel NN , , sometimes RB used VVN synonymously RB with IN wideband NN . SENT Broadband NP ISDN NP See NP BISDN NP . SENT Broadband NP LAN NP A NP Local NP Area NP Network NP LAN NP that WDT is VBZ distributed VVN via IN broadband NN coaxial JJ cable NN normally RB utilizing VVG CATV NP technology NN and CC broadband NN modems NNS . SENT Most RBS commonly RB used VVN with IN the DT Ethernet NP CSMA NP CD NP and CC Token JJ Bus NN . SENT Broadcast NN Delivery NN of IN transmission NN to TO two CD or CC more JJR stations NNS at IN the DT same JJ time NN over IN a DT common JJ transmission NN channel NN . SENT Examples NNS . SENT a DT bus NN type NN local JJ network NN , , a DT satellite NN system NN , , cable NN or CC microwave NN TV NN . SENT BSC NP See NP bisync NN . SENT Buffering VVG Process NN of IN temporarily RB storing VVG data NNS in IN RAM NN , , which WDT allows VVZ transmission NN devices NNS to TO accommodate VV differences NNS in IN data NN rates NNS and CC to TO perform VV error NN checking NN and CC retransmission NN of IN data NNS received VVN in IN error NN . SENT Bus NN A DT transmission NN path NN or CC channel NN . SENT typically RB an DT electrical JJ connection NN , , with IN one CD or CC more JJR conductors NNS , , wherein RB all DT attached VVN devices NNS receive VVP all DT transmissions NNS at IN the DT same JJ time NN . SENT a DT local JJ network NN topology NN , , such JJ as IN used VVN in IN Ethernet NP and CC the DT token JJ bus NN , , where WRB all DT network NN nodes NNS listen VVP to TO all DT transmissions NNS , , selecting VVG certain JJ ones NNS based VVN on IN address NN identification NN . SENT involves VVZ some DT sort NN of IN contention NN control NN mechanism NN for IN accessing VVG the DT bus NN transmission NN medium NN . SENT Byte NN An DT 8 CD bit NN quantity NN of IN information NN , , also RB generally RB referred VVN to TO in IN data NN communications NNS as IN an DT octet NN or CC character NN . SENT C SYM Back RB to TO Top JJ C NP band NN Portion NN of IN the DT electromagnetic JJ spectrum NN used VVN heavily RB for IN satellite NN and CC microwave NN transmission NN . SENT frequencies NNS of IN approximately RB 4 CD to TO 6 CD GHz NP . SENT CAD NN Computer NN Aided VVN Design NP . SENT CAI NP Computer NP Aided VVN Instruction NN . SENT Call NN Detail NN Recording NP CDR NP A DT feature NN of IN private JJ branch NN exchanges NNS where WRB each DT phone NN call NN is VBZ logged VVN , , typically RB by IN time NN and CC charges NNS , , and CC retrievable JJ through IN a DT PC NN by IN the DT network NN operator NN for IN departmental JJ billing NN . SENT Also RB called VVN Station NP Message NP Detail NN Recording NP SMDR NP . SENT CAM NN Computer NN Aided VVN Manufacturing NP . SENT CATV NP Community NP Antenna NN Television NN formal JJ , , or CC Cable NP Television NP colloquial JJ . SENT data NN communications NNS based VVN on IN radio NN frequency NN RF NP transmission NN , , generally RB using VVG 75 CD ohm NN coaxial JJ cable NN as IN the DT transmission NN medium NN . SENT communications NNS via IN coaxial JJ cable NN where WRB multiple JJ frequency NN divided VVN channels NNS allow VVP mixed JJ transmissions NNS to TO be VB carried VVN simultaneously RB . SENT broadband NN . SENT Carrier NP Signal NP A DT continuous JJ frequency NN capable JJ of IN being VBG modulated VVN or CC impressed VVN with IN a DT second JJ data NNS carrying VVG signal NN . SENT CBX NP Computerized JJ branch NN exchange NN . SENT see VV PBX NP . SENT The DT terms NNS CBX NP , , EPBX NP and CC PBX NP all RB represent VVP a DT computer NN controlled VVN Private NP Branch NP Exchange NP PBX NP . SENT CCITT NP Consulting NP Committee NP for IN International NP Telegraph NP and CC Telephone NP from IN the DT French NP , , Comite NP Consultatif NP International NP Telegraphique NP et CC Telephonique NP . SENT A DT committee NN of IN the DT International NP Telecommunications NPS Union NP of IN the DT UN NP that WDT advises VVZ the DT United NP Nations NPS on IN international JJ telecommunications NN standards NNS . SENT CCITT NP standards NNS will MD be VB the DT overall JJ voice NN data NN standards NNS of IN the DT 21 CD st NP century NN . SENT Sometimes RB referred VVN to TO as IN the DT ITU NP T NN committee NN . SENT CCS NP Centrum NN Hundreds NNS Call VV Seconds NNS . SENT A DT unit NN of IN traffic NN measurement NN in IN telephone NN traffic NN engineering NN that WDT represents VVZ a DT circuit NN , , connection NN , , or CC port NN where WRB usage NN of IN 36 CD ccs NNS , , or CC one CD Erlang NP , , is VBZ in IN use VV all PDT the DT time NN . SENT typical JJ usage NN for IN most JJS voice NN communications NNS ranges VVZ from IN about RB 3 CD to TO 10 CD ccs NNS per IN user NN station NN . SENT Cell NN a DT Referring VVG to TO the DT geographic JJ area NN served VVN by IN a DT single JJ transmitter NN in IN a DT cellular JJ radio NN network NN . SENT b SYM Referring VVG to TO a DT sub NN frame NN , , typically RB 53 CD bytes NNS , , used VVN for IN ATM NN statistically RB multiplexing VVG and CC Cell NN Relay NN switching NN . SENT Cellular NP Radio NP Technology NP employing VVG low JJ power NN radio NN transmission NN as IN an DT alternative NN to TO local JJ loops NNS for IN accessing VVG the DT switched VVN telephone NN network NN . SENT users NNS may MD be VB stationary JJ or CC mobile JJ . SENT When WRB mobile JJ they PP are VBP passed VVN under IN control NN of IN a DT central JJ site NN from IN one CD cell's NNS transmitter NN to TO an DT adjoining JJ one NN with IN minimal JJ switch NN over IN delay NN . SENT See VV AMPS NNS Cell NN Relay VV A DT high JJ bit NN rate NN asynchronous JJ or CC synchronous JJ data NNS multiplexing VVG and CC switching VVG technique NN based VVN on IN Fast JJ Packet NN technology NN . SENT CCITT NP I NP . SENT 422 CD specifies VVZ a DT 53 CD byte NN cell NN with IN a DT payload NN of IN 48 CD bytes NNS . SENT The DT 5 CD byte NN header NN contains VVZ virtual JJ channel NN and CC virtual JJ path NN identifiers NNS . SENT Cells NNS may MD be VB transmitted VVN along IN permanent JJ virtual JJ circuits NNS or CC mapped VVN into IN SONET NP frames NNS . SENT See VV ATM NN Central NP Office NP CO NP In IN telephony NN , , the DT Local NP Exchange NP Carrier NP LEC NP phone NN company NN switching VVG facility NN . SENT Also RB called VVN Local NP Exchange NP or CC wire NN center NN . SENT Refers VVZ to TO a DT Class NP 5 CD switching NN office NN , , at IN which WDT subscribers NNS local JJ loops NNS terminate VV . SENT handles VVZ a DT specific JJ geographic JJ area NN , , identified VVN by IN the DT first JJ three CD digits NNS of IN the DT local JJ telephone NN number NN . SENT Centrex NP A NP telephone NN company NN switching VVG service NN that WDT uses VVZ central JJ office NN switching VVG equipment NN to TO provide VV customers NNS PBX NP features NNS . SENT Typically RB , , the DT CO NP is VBZ partitioned VVN into IN 10 CD number NN blocks NNS and CC connected VVN via IN individual JJ extension NN lines NNS to TO the DT customer NN . SENT The DT Centrex NP CO NP is VBZ programmed VVN to TO provide VV advanced JJ telephone NN features NNS . SENT Nearly RB all DT telephone NN features NNS can MD be VB supplied VVN including VVG direct JJ inward RB calling VVG dialing NN DID VVD , , attendant NN consoles VVZ , , group NN pickup NN and CC least JJS cost NN routing NN . SENT This DT service NN has VHZ become VVN the DT best JJS selling VVG LEC NP service NN in IN the DT 1990 CD s PP . SENT It PP is VBZ very RB attractive JJ economically RB to TO small JJ and CC medium JJ size NN business NN . SENT CEPT NP Conference NP of IN European NP Postal NP and CC Telecommunications NP administrations NNS . SENT This DT standards NNS group NN represents VVZ most RBS international JJ telephone NN companies NNS outside JJ of IN North NP America NP Japan NP . SENT Channel NN In IN communications NNS , , a DT physical JJ or CC logical JJ path NN allowing VVG the DT transmission NN of IN information NN . SENT the DT path NN connecting VVG a DT data NN source NN and CC a DT data NNS sink VVP , , or CC receiver NN . SENT Channel NP bank NN DS NP 0 CD to TO DS NP 1 CD multiplex NN equipment NN primarily RB used VVN for IN analog JJ voice NN to TO Pulse NP Code NP Modulation NN PCM NP conversion NN and CC multiplexing VVG . SENT Typically RB used VVN in IN a DT telephone NN central JJ office NN as IN a DT subscriber NN loop NN carrier NN device NN . SENT The DT channel NN bank NN also RB detects VVZ and CC transmits VVZ signaling VVG information NN for IN each DT channel NN , , and CC inserts NNS a DT framing NN bit NN so IN time NN slots NNS allocated VVN to TO each DT channel NN can MD be VB identified VVN by IN the DT receiver NN . SENT Current JJ technology NN is VBZ the DT D NP 4 CD channel NN bank NN with IN ESF NP and CC B NP 8 CD ZS NP enhancements NNS . SENT Channel NP Attached VVD Describes VVZ the DT attachment NN of IN devices NNS directly RB to TO the DT input NN output NN channels NNS of IN a DT computer NN mainframe NN IBM NP . SENT Refers VVZ to TO devices NNS attached VVN to TO a DT controlling JJ unit NN by IN cables NNS rather RB than IN by IN telecommunications NN circuits NNS . SENT Character NN Standard NP bit NN representation NN of IN a DT symbol NN , , letter NN , , number NN , , or CC punctuation NN mark NN . SENT generally RB contained VVN within IN a DT byte NN . SENT Character NN code NN One CD of IN several JJ standard JJ sets NNS of IN binary JJ representations NNS for IN the DT alphabet NN , , numerals NNS , , and CC common JJ symbols NNS , , such JJ as IN ASCII NP , , EBCDIC NP , , and CC BCD NP . SENT Character NN oriented JJ Describing VVG a DT data NN communications NNS protocol NN that WDT carries VVZ control NN information NN encoded VVN as IN character NN strings NNS . SENT Example NN . SENT ETX NN end NN of IN transmission NN . SENT SOH NP start NN of IN header NN , , etc FW . SENT Checksum NP The DT term NN associated VVN with IN the DT result NN of IN a DT CRC NP calculation NN used VVN for IN frame NN error NN checking NN . SENT See VV Frame NP Check NP Sequence NN FCS NN and CC Cyclic JJ Redundancy NN Check NP CRC NP . SENT CICS NP Customer NN Information NP Control NP System NP . SENT and CC IBM NP program NN product NN and CC mainframe NN operating NN environment NN , , designed VVN to TO enable VV transactions NNS entered VVN at IN remote JJ terminals NNS to TO be VB processed VVN concurrently RB by IN user NN written VVN applications NNS programs NNS . SENT includes VVZ facilities NNS for IN building VVG and CC maintaining VVG databases NNS . SENT Circuit NP Generally RB referring VVG to TO a DT transmission NN medium NN connecting VVG two CD or CC more JJR electronic JJ devices NNS . SENT Circuit NN switching VVG The DT process NN of IN establishing VVG and CC maintaining VVG a DT circuit NN between IN two CD or CC more JJR users NNS on IN demand NN , , so RB the DT users NNS have VHP exclusive JJ use NN of IN the DT circuit NN until IN the DT connection NN is VBZ released VVN . SENT In IN digital JJ switching VVG Space NP Switching NP refers VVZ to TO the DT circuit NN switching VVG function NN for IN a DT dedicated JJ time NN slot NN . SENT CTIA NP Cellular NP Telecommunications NPS Industry NP Association NP CITA NP , , also RB called VVN TIA NP . SENT A DT group NN of IN manufacturers NNS and CC service NN providers NNS organized VVN to TO improve VV cellular JJ technology NN . SENT Primarily RB functions NNS in IN the DT U NP . SENT S NP . SENT . SENT Cladding VVG In IN optical JJ fiber NN , , that IN low JJ refractive JJ index NN material NN that WDT surrounds VVZ the DT core NN and CC provides VVZ optical JJ insulation NN and CC protection NN to TO the DT core NN . SENT Class NP X NP office NN Designation NN of IN a DT phone NN company NN switching VVG facility NN in IN the DT telephone NN hierarchy NN , , where WRB Class NP 5 CD is VBZ an DT end NN office NN , , Class NP 4 CD is VBZ a DT toll NN center NN , , Class NP 3 CD is VBZ a DT primary JJ center NN , , Class NP 2 CD is VBZ a DT sectional JJ center NN , , and CC Class NP 1 CD is VBZ a DT regional JJ center NN . SENT Since IN 1983 CD , , only RB Class NP 5 CD and CC Class NP 3 CD switches NNS are VBP employed VVN . SENT Class NN Of IN Service NP COS NN Designation NN for IN one CD of IN several JJ variable JJ network NN connection NN services NNS available JJ to TO the DT user NN of IN a DT network NN , , usually RB distinguished VVD by IN security NN offered VVN such JJ as IN encryption NN , , transmission NN priority NN , , and CC bandwidth NN . SENT the DT network NN user NN designates VVZ class NN of IN service NN at IN connection NN establishment NN , , typically RB using VVG a DT symbolic JJ name NN mapped VVN into IN a DT list NN of IN potential JJ routes NNS , , any DT of IN which WDT may MD provide VV the DT requested VVN service NN . SENT Clear JJ channel NN In IN digital JJ communications NNS , , the DT ability NN to TO provide VV a DT 64 CD kb NN s PP DS NP 0 CD for IN the DT customer NN . SENT Implies VVZ that DT telephone NN signaling VVG information NN is VBZ out RP of IN band NN and CC that IN a DT density NN of IN ones NNS 1 CD s NN is VBZ maintained VVN by IN B NP 8 CD ZS NP . SENT See VV B NP 8 CD ZS NP . SENT Clock NN An DT oscillator NN generated VVD signal NN that WDT provides VVZ a DT timing NN reference NN for IN a DT transmission NN link NN . SENT used VVN to TO control VV the DT timing NN functions NNS such JJ as IN sampling VVG interval NN , , signaling VVG rate NN , , and CC duration NN of IN signal NN elements NNS . SENT A DT digital JJ network NN typically RB has VHZ a DT master NN clock NN . SENT Cluster NN controller NN A DT device NN that WDT handles VVZ the DT remote JJ communications NNS processing VVG for IN multiple NN usually RB dumb JJ terminals NNS or CC workstations NNS . SENT generally RB considered VVN as IN an DT IBM NP 3270 CD family NN controller NN , , such JJ as IN the DT IBM NP 3274 CD , , or CC compatible JJ device NN . SENT CMOS NP Complementary JJ Metal NP Oxide NN Semiconductor NP . SENT A DT semiconductor NN that WDT utilizes VVZ a DT thin JJ layer NN of IN metal NN oxide NN to TO conduct VV current JJ between IN two CD identical JJ PN NP junctions NNS . SENT COMSAT NN Communications NP Satellite NP Corporation NP . SENT private JJ U NP . SENT S NP . SENT satellite NN carrier NN , , established VVN by IN Congress NP in IN 1962 CD , , for IN the DT coordination NN and CC construction NN of IN satellite NN communications NNS and CC facilities NNS for IN international JJ voice NN and CC data NN communications NNS . SENT Coaxial JJ cable NN A DT popular JJ transmission NN medium NN consisting VVG of IN a DT central JJ wire NN conductor NN surrounded VVN by IN dielectric JJ insulator NN and CC encased VVD in IN a DT wire NN mesh NN . SENT Coaxial JJ cable NN provides VVZ excellent JJ high JJ frequency NN transmission NN 50 CD 500 CD MHz NN and CC data NN rates NNS to TO 45 CD Mb NN s PP . SENT Commonly RB uses VVZ as IN CATV NP transmission NN cable NN , , 56 CD kb NN s VVZ 45 CD Mb NN s PP data NNS cables NNS and CC ethernet NP LAN NP connections NNS . SENT Also RB called VVD coax VV . SENT CODEC NP Coder NP decoder NN . SENT an DT integrated JJ circuit NN IC NP , , or CC series NN of IN ICs NN , , that WDT performs VVZ analog JJ to TO digital JJ conversion NN of IN a DT 0 CD 4 CD kHz NN voice NN signal NN to TO a DT 64 CD Kb NP s PP PCM NP digital JJ bit NN stream NN . SENT The DT term NN also RB refers VVZ to TO an DT analog NN to TO digital JJ television NN signal NN converter NN , , Video NP CODEC NP . SENT Code NP Division NP Multiple JJ Access NP CDMA NP A DT spread NN spectrum NN access NN technique NN that WDT addresses VVZ individual JJ bit NN groupings NNS to TO specific JJ radio NN receivers NNS , , either CC satellite NN or CC cellular JJ telephones NNS . SENT The DT signal NN is VBZ transmitted VVN just RB above IN noise NN level NN across IN the DT available JJ bandwidth NN . SENT CDMA NP is VBZ in IN use NN as IN a DT satellite NN technology NN but CC will MD require VV much JJ additional JJ development NN for IN cellular JJ telephones NNS . SENT Common JJ carrier NN In IN the DT United NP States NPS , , any DT supplier NN of IN transmission NN facilities NNS or CC services NNS to TO the DT general JJ public NN that WDT is VBZ authorized VVN to TO provide VV such JJ facilities NNS or CC services NNS by IN the DT appropriate JJ regulatory JJ authority NN . SENT A DT supplier NN of IN the DT Public NP Switched VVD Telephone NP Network NP PSTN NP . SENT Either CC a DT Local NP Exchange NP Carrier NP LEC NP or CC an DT Inter NP eXchange NN Carrier NP IXC NP . SENT Common JJ Channel NP Interoffice JJ Signaling VVG CCIS NP A DT telephone NN signaling VVG technique NN that WDT places VVZ multiple JJ channel NN signaling VVG information NN in IN a DT separate JJ channel NN along IN with IN network NN management NN information NN . SENT CCIS NNS was VBD introduced VVN by IN AT IN T NN in IN the DT 1970 CD s PP and CC used VVN modems NNS to TO carry VV signaling VVG information NN . SENT CCITT NN Signaling VVG System NP 7 CD SS NP 7 CD is VBZ the DT current JJ standard NN CCIS NP and CC is VBZ used VVN by IN nearly RB all DT IXC NP and CC many JJ LEC NP carriers NNS . SENT SS NP 7 CD uses VVZ a DT separate JJ fast JJ packet NN switched VVD network NN of IN DS NP 0 CD channels NNS for IN network NN control NN . SENT Companding VVG Compressing VVG expanding VVG . SENT the DT process NN of IN reducing VVG the DT bandwidth NN required VVN for IN representation NN of IN an DT analog JJ waveform NN for IN transmission NN , , and CC then RB reconstructing VVG most JJS of IN the DT original JJ waveform NN at IN the DT receiving VVG end NN . SENT In IN digital JJ voice NN PCM NP , , a DT nonlinear JJ allocation NN of IN sampling VVG intervals NNS used VVN to TO lower JJR quantization NN error NN over IN a DT wider JJR dynamic JJ range NN of IN input NN signals NNS . SENT Concentrator NN Any DT communications NNS device NN that WDT allows VVZ a DT shared VVN transmission NN medium NN to TO accommodate VV more JJR data NN sources NNS than IN there EX are VBP channels NNS currently RB available JJ within IN the DT transmission NN medium NN . SENT Conditioning NN Extra JJ cost NN options NNS that IN users NNS may MD apply VV to TO leased VVN , , or CC dedicated VVN , , voice NN grade NN telephone NN company NN circuits NNS used VVN for IN data NN transmission NN , , that WDT will MD generally RB allow VV for IN higher JJR quality NN and CC or CC higher JJR speed NN data NNS transmission NN . SENT Frequency NN response NN attenuation NN distortion NN and CC envelope NN delay NN distortion NN are VBP improved VVN by IN C NP conditioning NN , , available JJ in IN grades NNS C NP 1 CD , , C NP 2 CD , , or CC C $ 4 CD . SENT Signal NN to TO noise NN ratio NN is VBZ improved VVN by IN D NP 1 CD conditioning NN . SENT Control NN characters NNS In IN data NN communications NNS , , extra JJ transmitted JJ characters NNS used VVN to TO control VV or CC facilitate VV data NN transmission NN between IN terminal JJ equipment NN DTE NN and CC data NN circuit NN terminating VVG equipment NN DCE NN , , or CC peripheral JJ equipment NN . SENT See VV byte NN oriented JJ protocol NN . SENT Core NN The DT central JJ light JJ transmission NN part NN of IN the DT optical JJ fiber NN with IN a DT refractive JJ index NN higher JJR than IN that DT of IN the DT cladding NN . SENT CPE NP Customer NN premises NNS equipment NN . SENT in IN telephony NN , , equipment NN that IN interfaces NNS to TO the DT telephone NN network NN and CC physically RB resides VVZ at IN the DT user's JJ location NN . SENT includes VVZ most RBS , , but CC not RB all RB , , gear NN referred VVD to TO as IN network NN channel NN terminating VVG equipment NN NTE NN . SENT CPU NN Central NP Processing NP Unit NP . SENT CRC NP Cyclic JJ Redundancy NN Check NP . SENT A DT register NN mathematical JJ calculation NN using VVG a DT polynomial JJ algorithm NN applied VVN to TO each DT bit NN in IN a DT transmitted JJ frame NN , , that WDT is VBZ matched VVN with IN an DT identical JJ algorithm NN within IN the DT receiver NN . SENT A DT match NN produces VVZ a DT 99 CD . SENT 99 CD error NN free JJ result NN typically RB based VVN on IN a DT 16 CD bit NN field NN appended VVN to TO the DT transmitted JJ frame NN . SENT Used VVN within IN all DT modern JJ data NN communications NNS protocols NNS . SENT Crossbar NN switch VV An DT electromechanical JJ telephone NN switch NN that WDT uses VVZ moving VVG electronic JJ bars NNS to TO connect VV vertical JJ and CC horizontal JJ leads NNS . SENT Introduced VVN by IN AT IN T NN in IN the DT 1930 CD s PP , , this DT technology NN is VBZ still RB employed VVN in IN some DT telephone NN central JJ offices NNS . SENT Crosstalk NN Unwanted JJ transference NN of IN electrical JJ energy NN from IN one CD transmission NN channel NN to TO another DT , , usually RB adjacent JJ , , channel NN . SENT CSMA NP CD NP Carrier NP Sense NN Multiple NN Access NP with IN Collision NN Detection NN . SENT A DT popular JJ Media NP Access NP Control NP MAC NN technology NN , , where WRB all DT devices NNS attached VVN to TO a DT local JJ network NN listen VV for IN transmissions NNS in IN progress NN before IN attempting VVG to TO transmit VV and CC , , if IN two CD or CC more JJR begin VVP transmitting VVG at IN the DT same JJ time NN , , each DT backs NNS off RB defers VVZ for IN a DT random JJ period NN of IN time NN determined VVN by IN a DT set VVN algorithm NN before IN again RB attempting VVG to TO transmit VV again RB . SENT Used VVN in IN packet NN radio NN and CC the DT ethernet NP . SENT CSU NP Channel NP Service NP Unit NP . SENT A DT customer NN premises NN equipment NN CPE NN device NN used VVN to TO terminate VV a DT DS NP 1 CD or CC DS NP 0 CD 56 CD 64 CD kb NN s PP digital JJ circuit NN . SENT The DT CSU NP must MD comply VV with IN FCC NP rules NNS and CC store NN error NN information NN provided VVN by IN the DT Extended JJ Super NP Frame NP ESF NP . SENT The DT CSU NP also RB performs VVZ line NN conditioning NN , , protection NN , , loop NN back NN and CC timing NN functions NNS . SENT CRT NP Cathode NN ray NN tube NN CTS NP Clear NP To TO Send VV . SENT modem NN control NN code NN . SENT CVSD JJ Continuous JJ Variable NN Slope NP Delta NP modulation NN . SENT A DT speech NN digitizing VVG and CC encoding VVG technique NN that WDT uses VVZ a DT one CD bit NN sample NN to TO encode VV to TO difference NN between IN two CD successive JJ signal NN levels NNS . SENT sampling VVG usually RB done VVN at IN 32 CD , , 000 CD times NNS a DT second NN , , although IN some DT implementations NNS employ VVP lower JJR sampling NN rates NNS . SENT Cyclic JJ Redundancy NN Check NP CRC NP An DT error NN checking NN procedure NN commonly RB used VVN in IN data NN communications NNS in IN which WDT each DT transmitted JJ bit NN in IN a DT frame NN is VBZ applied VVN to TO a DT register NN containing VVG series NN of IN XOR NP gates NNS thereby RB solving VVG a DT polynomial JJ equation NN . SENT The DT result NN of IN this DT operation NN is VBZ appended VVN to TO the DT completed VVN frame NN and CC compared VVN to TO an DT identical JJ register NN in IN the DT receiver NN . SENT A DT match NN equals VVZ an DT error NN free JJ frame NN . SENT There EX are VBP several JJ standard JJ CRC NP checks NNS . SENT CRC NP 6 CD used VVN in IN the DT DS NP 1 CD ESF NP , , CRC NP 16 CD used VVN as IN the DT ISO NP data NN communications NNS standard JJ CRC NP 32 CD used VVN in IN the DT IEEE NP 802 CD LAN NP standards NNS . SENT See VV FCS NN . SENT Checksum NP . SENT D NP Top NP DACS NP Digital NP Access NP and CC Cross NP Connect VVP System NP . SENT A DT TSI NP switch NN that WDT switches VVZ DS NP 0 CD channels NNS among IN DS NP 1 CD data NN streams NNS . SENT Computer NN controlled VVN and CC designed VVN for IN keyboard NN entry NN as IN opposed VVN to TO automatic JJ switching NN . SENT There EX are VBP many JJ uses NNS , , including VVG semi NN automatic JJ test NN boards NNS , , digital JJ circuit NN concentration NN , , trunk NN switching NN , , and CC alternate JJ routing NN . SENT The DT term NN DACS NP was VBD extended VVN for IN DS NP 0 CD DS NP 1 CD switching NN but CC has VHZ been VBN applied VVN to TO DS NP 1 CD DS NP 3 CD switching NN . SENT Many JJ large JJ DACS NP units NNS include VVP combined JJ switching VVG systems NNS that WDT allow VVP DS NP 0 CD switching NN among IN DS NP 3 CD s PP , , always RB with IN demultiplexing VVG of IN the DT DS NP 3 CD data NN streams NNS . SENT IXC NP and CC LEC NP carriers NNS offer NN partitioned VVN DACS NP service NN under IN customer NN control NN , , which WDT allows VVZ the DT customer NN to TO control VV a DT Virtual JJ Private NP Network NP VPN NP within IN the DT carrier's NNS network NN . SENT Data NP Compression NN Application NN of IN several JJ techniques NNS that WDT reduce VVP the DT number NN of IN bits NNS required VVN to TO represent VV information NN in IN data NN transmission NN or CC storage NN , , therefore RB conserving VVG bandwidth NN and CC or CC memory NN . SENT CCITT NP V NN . SENT 42 CD is VBZ the DT modem NN transmission NN standard NN . SENT Data NP Encryption NN Standard NP DES NP Cryptographic JJ algorithm NN designed VVN by IN the DT National NP Bureau NP of IN Standards NPS to TO encipher VV and CC decipher VV data NNS using VVG a DT 64 CD bit NN key NN . SENT specified VVN in IN Federal NP Information NP Processing NP Standard NP Publication NN 46 CD , , dated VVN January NP 15 CD , , 1977 CD . SENT There EX have VHP been VBN several JJ modifications NNS to TO this DT standard NN . SENT Datagram NN In IN packet NN switching NN , , a DT self NN contained VVD packet NN message NN . SENT Each DT datagram NN carries VVZ routing VVG information NN . SENT Datagrams NNS are VBP required VVN for IN connectionless JJ data NNS service NN . SENT No DT longer RB offered VVN in IN the DT X NN . SENT 25 CD standard NN . SENT The DT DDN NP ARPANET NP is VBZ organized VVN around IN a DT series NN of IN datagram NN messages NNS . SENT Data NP PBX NP A NP PBX NP switch NN that WDT allows VVZ digital JJ transmission NN without IN modems NNS as RB well RB as IN voice NN . SENT An DT option NN offered VVD today NN by IN nearly RB all DT manufacturers NNS . SENT Data NP link NN Refers VVZ to TO level VV 2 CD of IN the DT OSI NP model NN . SENT A DT serial JJ data NN communications NNS connection NN between IN two CD adjacent JJ node NN . SENT Data NNS set VVD A DT modem NN . SENT infrequently RB used VVN today NN except IN within IN the DT telephone NN carrier NN industry NN . SENT Dataphone NP A NP service NN and CC trademark NN of IN AT IN T NN . SENT generically RB refers VVZ to TO the DT transmission NN of IN data NNS over IN the DT phone NN network NN Dataphone NP Digital NP Service NP , , or CC DDS NP using VVG 56 CD Kb NP s PP or CC 64 CD Kb NP s PP channels NNS . SENT dB NP Decibel NN . SENT a DT unit NN of IN measurement NN used VVN to TO express VV the DT ratio NN of IN two CD values NNS , , usually RB the DT power NN of IN electrical JJ signals NNS . SENT equal JJ to TO 10 CD times NNS the DT logarithm NN of IN the DT power NN output NN input NN of IN the DT channel NN . SENT When WRB voltage NN or CC current JJ are VBP compared VVN , , the DT formula NN would MD be VB 20 CD log NN output NN input NN . SENT dBm NP Decibel NN referred VVD to TO one CD milliwatt NN . SENT A DT milliwatt NN is VBZ a DT power NN measurement NN , , therefore RB , , the DT formula NN would MD be VB dBm NP 10 CD log NN measured VVN power NN in IN milliwatts NP 1 CD . SENT Used VVN in IN telephony NN to TO refer VV to TO relative JJ strength NN of IN a DT signal NN . SENT dBr NP 0 CD Decibel NN referred VVD to TO a DT 0 CD value NN set VVN by IN the DT telephone NN company NN . SENT dBrn NP 0 CD Decibel NN referenced VVN to TO the DT existing JJ noise NN level NN of IN a DT telephone NN circuit NN . SENT Used VVN in IN telephony NN as IN a DT signal NN to TO noise NN ratio NN measurement NN . SENT DCE NP Data NP Circuit NP terminating VVG Equipment NP . SENT sometimes RB , , Data NP Communications NPS Equipment NP . SENT Equipment NN that WDT is VBZ either DT part NN of IN the DT network NN , , an DT access NN point NN to TO the DT network NN , , a DT network NN node NN , , or CC equipment NN at IN which WDT a DT network NN circuit NN terminates VVZ . SENT In IN the DT case NN of IN an DT RS NP 232 CD D NP connection NN , , the DT modem NN is VBZ usually RB regarded VVN as IN DCE NP , , while IN the DT user NN device NN is VBZ DTE NP , , or CC data NNS terminal NN equipment NN . SENT in IN a DT CCITT NP X NP . SENT 25 CD connection NN , , the DT network NN access NN and CC packet NN switching VVG node NN is VBZ viewed VVN as IN the DT DCE NP . SENT DDCMP NP Digital NP Data NP Communications NPS Message NP Protocol NP Digital NP Equipment NP Corporation NP . SENT Similar JJ to TO HDLC NP . SENT DDS NP Dataphone NP Digital NP Service NP . SENT The DT first JJ private JJ line NN digital JJ service NN offered VVN by IN AT IN T NN , , with IN data NN rates NNS typically RB at IN 2 CD . SENT 4 CD , , 4 CD . SENT 8 CD , , 9 CD . SENT 6 CD and CC 56 CD Kb NP s PP . SENT now RB a DT part NN of IN the DT services NNS listed VVN by IN AT IN T NN under IN the DT Accunet NP family NN of IN offerings NNS . SENT All DT LEC NP and CC IXC NP carriers NNS offer VVP similar JJ services NNS . SENT DES NP See NP Data NP Encryption NN Standard NP National NP Bureau NP of IN Standards NPS . SENT Dedicated JJ line NN A DT dedicated JJ circuit NN , , a DT non JJ switched VVN channel NN , , or CC a DT private JJ line NN . SENT See VV leased VVN line NN . SENT Demodulation NN The DT process NN of IN retrieving VVG an DT original JJ signal NN from IN a DT modulated VVN carrier NN wave NN . SENT See VV modulation NN . SENT Dial VV up RP Describing VVG the DT process NN of IN establishing VVG a DT temporary JJ connection NN via IN the DT switched VVN telephone NN network NN . SENT Digital JJ Referring VVG to TO communications NNS procedures NNS , , techniques NNS , , and CC equipment NN where WRB information NN is VBZ encoded VVN as IN either CC a DT binary JJ 1 CD or CC 0 CD . SENT Digital NP Cellular NP Referring VVG to TO cellular JJ telephony NN using VVG compressed VVN digital JJ speech NN and CC digital JJ modulation NN , , as RB opposed VVN to TO analog JJ voice NN channels NNS . SENT Digital NP techniques NNS will MD improve VV the DT use NN of IN available JJ spectrum NN by IN factors NNS of IN 3 CD to TO 7 CD while IN reducing VVG noise NN and CC allowing VVG the DT efficient JJ transmission NN of IN digital JJ information NN Fax NP Data NP . SENT Current JJ plans NNS call VVP for IN a DT gradual JJ migration NN to TO digital JJ cellular JJ technology NN . SENT Digital NP Local NP Loop NP In IN ISDN NP , , describing VVG the DT existing JJ two CD wire NN telephone NN connection NN between IN the DT CO NP or CC remote JJ and CC the DT customer NN NT NP 1 CD over IN which WDT Basic NP Access NP is VBZ provided VVN . SENT Digital NP Switching NP The DT process NN of IN establishing VVG and CC maintaining VVG a DT connection NN , , under IN stored VVN program NN control NN , , where WRB binary NN encoded VVD information NN is VBZ routed VVN between IN an DT input NN and CC an DT output NN port NN through IN a DT virtual JJ circuit NN established VVN by IN a DT time NN shared VVD matrix NN Time NP Multiplex NN Switching NP TMS NP or CC by IN buffering VVG data NN streams NNS and CC interchanging VVG time NN slots NNS Time NP Slot NP Interchange VV TSI NP . SENT Both DT techniques NNS are VBP more RBR efficient JJ than IN dedicated JJ matrix NN circuits NNS . SENT Direct JJ Inward RB Dialing NN DID VVD A DT PBX NP option NN wherein RB the DT CO NP transfers VVZ the DT last JJ four CD digits NNS of IN an DT incoming JJ call NN to TO the DT PBX NP and CC the DT extension NN is VBZ then RB reached VVN directly RB without IN going VVG through IN an DT operator NN . SENT Direct NP Outward RB Dialing VVG DOD NP A NP PBX NP feature NN allowing VVG an DT internal JJ caller NN at IN an DT extension NN to TO dial VV an DT external JJ number NN without IN going VVG through IN an DT operator NN . SENT Typically RB accessed VVN by IN dialing VVG 9 CD followed VVN by IN the DT external JJ number NN . SENT Dispersion NN The DT cause NN of IN bandwidth NN limitations NNS in IN a DT fiber NN . SENT Dispersion NN causes VVZ a DT broadening VVG of IN input NN pulses NNS along IN the DT length NN of IN the DT fiber NN . SENT Two CD major JJ types NNS are VBP . SENT a DT modal JJ dispersion NN caused VVN by IN differential JJ optical JJ path NN lengths NNS in IN a DT multimode NN fiber NN , , and CC b LS material NN dispersion NN caused VVN by IN a DT differential JJ delay NN of IN various JJ wavelengths NNS of IN light NN in IN a DT waveguide NN material NN . SENT Distortion NN The DT corruption NN of IN a DT signal NN caused VVN by IN time NN delay NN , , harmonics NNS , , frequency NN response NN noise NN or CC other JJ disturbances NNS . SENT Distributed VVN Data NP Processing NP DDP NP Describing VVG a DT network NN of IN geographically RB dispersed VVD , , though RB logically RB interconnected VVN , , data NNS processing VVG nodes NNS . SENT generally RB configured VVN so RB that IN nodes NNS can MD share VV common JJ resources NNS , , such JJ as IN a DT file NN server NN , , a DT print NN server NN , , host NN applications NNS , , or CC a DT database NN . SENT communications NNS between IN DDP NP nodes NNS may MD be VB sporadic JJ or CC intensive JJ , , interactive JJ or CC batch NN . SENT also RB , , distributed VVN processing NN . SENT Distribution NN frame NN A DT structure NN typically RB wall NN mounted VVN for IN terminating VVG telephone NN wiring NN . SENT Usually RB consisting VVG of IN 50 CD pair NN blocks NNS designed VVN for IN punching VVG permanent JJ wires NNS to TO interconnect VV telephone NN and CC or CC data NNS LAN NP circuits NNS . SENT Divestiture NN The DT breakup NN of IN AT IN T NN , , mandated VVN by IN the DT federal JJ courts NNS based VVN on IN an DT antitrust JJ accord NN reached VVN between IN AT IN T NN and CC the DT U NP . SENT S NP . SENT Department NP of IN Justice NP . SENT effective JJ January NP 1 CD , , 1984 CD . SENT most RBS notable JJ effects NNS include VVP the DT separation NN of IN 22 CD AT IN T NN owned VVN local JJ Bell NP operating NN companies NNS BOC NP into IN seven CD independent JJ regional JJ Bell NP holding NN companies NNS , , the DT requirement NN for IN AT IN T NN to TO manufacture VV and CC market VV customer NN premises NNS equipment NN through IN a DT separate JJ subsidiary NN , , and CC use VV of IN the DT Bell NP name NN an DT logo NN only RB by IN the DT divested JJ BOCs NP . SENT Domain NN In IN IBM's NP Systems NPS Network NP Architecture NP SNA NP , , a DT host NN based VVN Systems NP Services NPS Control NP Point NP SSCP NP and CC its PP$ Sub NP Area NP nodes NNS . SENT Domains NNS are VBP interconnecting VVG through IN a DT boundary NN function NN gateway NN . SENT Driver NN Usually RB a DT software NN module NN that WDT , , under IN control NN of IN the DT processor NN , , manages VVZ an DT I NN O NN port NN to TO an DT external JJ device NN , , such JJ as IN a DT serial JJ RS NP 232 CD C NP port NN to TO a DT modem NN . SENT DQDB NP Distributed NP Queue NN Dual JJ Bus NN . SENT A DT metropolitan JJ area NN network NN MAN NN technique NN standardized JJ by IN IEEE NP 802 CD . SENT 6 CD in IN late JJ 1991 CD . SENT The DT DQDB NP name NN describes VVZ the DT LLC NN MAC NN technique NN of IN the DT MAN NN . SENT The DT DQDB NP MAN NN is VBZ designed VVN to TO provide VV LECs NP with IN a DT high JJ speed NN open JJ access NN data NNS bus NN to TO serve VV customers NNS with IN packet NN type NN requirements NNS at IN speeds NNS of IN 45 CD Mb NN s PP and CC above IN . SENT The DT future NN of IN this DT technology NN will MD depend VV on IN user NN requirements NNS and CC the DT cost NN advantage NN over IN direct JJ DS NP 3 CD or CC SONET NP connection NN . SENT DS NP 0 CD Digital NP Signal NP level NN 0 CD . SENT The DT bandwidth NN of IN a DT digitized VVN PCM NP voice NN signal NN , , 64 CD kb NN s PP . SENT May MD carry VV voice NN or CC data NNS . SENT DS NP 1 CD Digital NP Signal NP level NN 1 CD . SENT A DT 1 CD . SENT 544 CD Mb NN s PP digital JJ signal NN consisting VVG of IN 24 CD DS NP 0 CD s PP and CC a DT framing NN bit NN 193 CD bits NNS transmitted VVD 8000 CD times NNS per IN second JJ . SENT May MD be VB carried VVN on IN a DT T NN 1 CD facility NN or CC other JJ transmission NN medium NN . SENT DS NP 1 CD C NP Digital NP Signal NP level NN 1 CD C NP . SENT Term NN describing VVG a DT 3 CD . SENT 152 CD Mb NN s PP digital JJ signal NN comprised VVN of IN two CD DS NP 1 CD s PP . SENT Used VVN in IN many DT older JJR LEC NP installations NNS but CC rarely RB installed VVN today NN . SENT DS NP 2 CD Digital NP Signal NP level NN 2 CD . SENT A DT multiplexed JJ 6 CD . SENT 312 CD Mb NN s PP digital JJ signal NN comprised VVN of IN four CD DS NP 1 CD s PP and CC 96 CD DS NP 0 CD s PP . SENT Often RB carried VVN on IN a DT T NN 2 CD facility NN which WDT is VBZ the DT basis NN of IN the DT Subscriber NN Line NP Carrier NP SLC NP 96 CD used VVN as IN a DT common JJ LEC NP remote JJ concentrator NN . SENT DS NP 3 CD Digital NP Signal NP level NN 3 CD . SENT A DT multiplexed JJ 44 CD . SENT 736 CD Mb NN s PP digital JJ signal NN comprised VVN of IN 7 CD DS NP 2 CD or CC 28 CD DS NP 1 CD signals NNS . SENT Contains VVZ 672 CD DS NP 0 CD channels NNS . SENT Multiple JJ DS NP 3 CD s PP are VBP multiplexed VVN onto IN fiber NN optical JJ carriers NNS . SENT DSU NP Data NP Service NP Unit NP . SENT Customer NN premises NNS equipment NN CPE NN used VVN to TO interface NN to TO a DT digital JJ circuit NN . SENT Commonly RB associated VVN with IN DDS NP termination NN . SENT Provides VVZ DTE NP termination NN of IN data NN circuit NN and CC is VBZ now RB generally RB combined VVN with IN a DT Channel NP Service NP Unit NP CSU NP . SENT Performs VVZ conversion NN of IN customer's JJ data NNS stream NN to TO bipolar JJ format NN for IN transmission NN . SENT DSX NP Digital NP signal NN cross NN connect VVP . SENT A DT patch NN panel NN for IN the DT testing NN and CC cross NN connection NN of IN DS NP as IN in IN DS NP 1 CD , , DS NP 2 CD circuits NNS . SENT DTE NP Data NP terminal NN equipment NN . SENT generally RB end VV user NN devices NNS , , such JJ as IN terminals NNS and CC computers NNS , , that WDT connect VVP to TO DCE NP , , which WDT either RB generate VV or CC receive VV the DT data NNS carried VVN by IN the DT network NN . SENT The DT RS NP 232 CD , , V NN . SENT 35 CD and CC X NP . SENT 21 CD connections NNS are VBP common JJ DCE NP to TO DTE NP interfaces NNS . SENT DTMF NP Dual JJ Tone NP Multi NNS Frequency NN . SENT The DT signal NN , , consisting VVG of IN two CD tones NNS , , produced VVN by IN a DT standard JJ telephone NN push NN button NN Touch NP Tone NP 12 CD key JJ pad NN . SENT The DT signal NN produced VVN replaced VVD the DT older JJR pulse NN dialing VVG of IN rotary JJ phones NNS . SENT E NP Top NP Echo NP The DT reflection NN back RB to TO the DT sender NN of IN transmitted JJ signal NN energy NN . SENT The DT amount NN of IN delay NN in IN an DT echo NN depends VVZ on IN the DT distance NN from IN the DT transmitter NN to TO the DT point NN of IN reflection NN . SENT Eliminated VVN by IN signal NN processors NNS called VVD Echo NP Cancellers NNS . SENT Echo NP cancellation NN A DT new JJ technique NN that IN samples NNS the DT transmission NN and CC echo NN signal NN and CC inserts NNS an DT out NN of IN phase NN cancellation NN signal NN into IN the DT return NN channel NN . SENT Requires VVZ advanced JJ signal NN processing NN techniques NNS . SENT EDP NP Electronic NP Data NP Processing NP . SENT EIA NP Electronic NP Industries NPS Association NP . SENT A DT standards NNS organization NN that WDT developed VVD the DT RS NP 232 CD and CC other JJ interfaces NNS . SENT EMI NP Electromagnetic JJ interference NN . SENT Radiation NN leakage NN outside IN of IN a DT transmission NN medium NN that IN results NNS mainly RB from IN the DT use NN of IN high JJ frequency NN wave NN energy NN . SENT May MD be VB reduced VVN by IN shielding VVG . SENT Encapsulation NN The DT addition NN of IN control NN information NN to TO a DT data NN packet NN for IN use NN by IN a DT higher JJR level NN protocol NN . SENT Equalization NN In IN the DT telephone NN network NN , , the DT spacing NN and CC operation NN of IN amplifiers NNS so IN the DT gain NN provided VVN by IN the DT amplifier NN coincides VVZ with IN the DT signal NN loss NN at IN the DT same JJ frequency NN . SENT Usually RB accomplished VVN by IN a DT combination NN of IN adjustable JJ coils NNS , , capacitors NNS , , and CC or CC resistors NNS . SENT See VV Conditioning NN . SENT Erlang NP Standard NP unit NN of IN measurement NN of IN telecommunications NN traffic NN capacity NN and CC usage NN demand NN . SENT Used VVN in IN traffic NN engineering NN for IN throughput NN and CC capacity NN planning NN . SENT An DT Erlang NP equals VVZ 36 CD ccs NNS , , which WDT represents VVZ a DT conventional JJ telecommunications NN traffic NN plan NN that WDT is VBZ in IN use NN full JJ time NN . SENT ESF NP Extended VVD Super NP Frame NP . SENT A DT technique NN of IN combining VVG 24 CD DS NP 1 CD T NN 1 CD frames NNS so RB that IN the DT repeating JJ 24 CD framing NN bits NNS F NN bits NNS can MD be VB used VVN to TO carry VV encoded VVN network NN management NN data NNS as RB well RB as IN a DT CRC NP 6 CD frame NN check NN sequence NN . SENT ESS NP Electronic NP Switching NP System NP . SENT one CD of IN a DT family NN of IN AT IN T NN manufactured VVN , , stored VVD program NN control NN , , central JJ office NN switches NNS . SENT most RBS prevalent JJ are VBP the DT Nos NNS . SENT 1 CD , , 1 CD A NP , , 4 CD , , and CC 5 CD switches NNS . SENT Ethernet NP A NP Local NP Area NP Network NP LAN NP trademarked VVD product NN of IN Xerox NP Corp NP . SENT characterized VVN by IN 10 CD Mb NN s PP baseband NN transmission NN over IN a DT shielded VVN coaxial JJ cable NN and CC employing VVG CSMA NP CD NP media NNS access NN control NN mechanism NN . SENT Standardized JJ by IN IEEE NP 802 CD . SENT 3 CD which WDT also RB allows VVZ other JJ cable NN designs NNS . SENT Exchange NN Referring VVG to TO the DT local JJ telephone NN Central NP Office NP CO NP , , or CC to TO any DT subscriber NN telephone NN switch NN , , as RB in IN Private NP Branch NP Exchange NP PBX NP . SENT ESF NP Extended VVD Super NP Frame NP . SENT A DT group NN of IN 24 CD D NP 4 CD frames NNS used VVN together RB . SENT In IN addition NN to TO a DT synchronization NN pattern NN , , the DT framing NN bits NNS also RB carry VVP CRC NP 6 CD error NN information NN from IN the DT preceding VVG ESF NP and CC a DT data NNS channel NN , , the DT Facilities NP Data NP Link NN , , that WDT reports VVZ detected VVN errors NNS . SENT Replaced VVN the DT superframe JJ standard NN in IN 1983 CD . SENT F SYM Top JJ Facsimile NN The DT communications NNS process NN in IN which WDT graphics NNS or CC text NN documents NNS are VBP scanned VVN , , bit NN encoded VVD and CC transmitted VVD via IN a DT modem NN dial NN up IN phone NN line NN . SENT The DT CCITT NP standards NNS for IN information NN representation NN and CC transmission NN Group NP 1 CD analog NN , , with IN page NN transmission NN in IN four CD or CC six CD minutes NNS . SENT Group NP 2 CD , , with IN page NN transmission NN in IN two CD or CC three CD minutes NNS . SENT and CC Group NP 3 CD digital JJ with IN page NN transmission NN in IN less JJR than IN one CD minute NN . SENT Also RB called VVN fax NN . SENT Fading VVG A DT phenomenon NN , , in IN microwave NN radio NN transmission NN , , where WRB atmospheric JJ refraction NN or CC rain NN attenuation NN causes VVZ a DT drop NN in IN receive VV signal NN level NN . SENT Fast JJ Packet NN Switching NP A DT message NN switching VVG approach NN that WDT attempts VVZ to TO minimize VV packet NN processing NN time NN at IN each DT node NN to TO utilize VV high JJ speed NN data NN channels NNS effectively RB . SENT Frame NN Relay NN , , Cell NN Relay NN , , and CC SS NP 7 CD are VBP examples NNS . SENT Fax NP See NP facsimile NN . SENT FCC NP Federal NP Communications NPS Commission NP . SENT board NN of IN commissioners NNS appointed VVN by IN the DT President NP under IN the DT Communications NP Act NP of IN 1934 CD , , with IN the DT authority NN to TO regulate VV all DT interstate JJ telecommunications NNS originating VVG in IN the DT United NP States NPS . SENT FCS NN See VV Frame NP Check NP Sequence NN FDDI NP Fiber NN Distributed NP Data NP Interface NP . SENT A DT LAN NP or CC MAN NN , , network NN standard NN IEEE NP 802 CD . SENT 7 CD based VVN on IN two CD counter NN rotating VVG fiber NN rings NNS operating VVG at IN 100 CD Mb NN s PP . SENT The DT LLC NN MAC NN is VBZ a DT modification NN of IN the DT token JJ ring NN . SENT Designed VVN as IN a DT LAN NP backbone NN , , or CC campus NN ring NN , , for IN distributing VVG data NNS to TO other JJ Local NP Area NP Networks NPS . SENT The DT bandwidth NN is VBZ considered VVN too RB low JJ to TO meet VV the DT requirements NNS for IN a DT MAN NN although IN metropolitan JJ area NN distances NNS are VBP possible JJ . SENT Gaining VVG wide JJ acceptance NN in IN campus NN environments NNS . SENT FDM NP Frequency NN Division NN Multiplexing VVG . SENT A DT technique NN that WDT translates VVZ several JJ low JJ frequency NN channels NNS onto IN one CD broadband NN high JJ frequency NN channel NN . SENT Used VVN in IN telephony NN , , LAN NP , , CATV NP applications NNS . SENT See VV Frequency NN Division NN Multiplexing VVG . SENT Frequency NN Division NN Multiple JJ Access NP FDMA NP An DT access NN technique NN that WDT assigns VVZ several JJ users NNS of IN a DT radio NN channel NN to TO a DT specific JJ frequency NN slot NN . SENT Frequency NN Division NN Multiplexing VVG FDM NP is VBZ identical JJ except IN that WDT FDMA NP has VHZ a DT control NN channel NN that WDT dynamically RB reassigns VVZ frequency NN channels NNS among IN the DT users NNS . SENT Used VVN as IN a DT multiple JJ access NN technique NN for IN satellite NN and CC cellular JJ telephone NN receivers NNS . SENT FDX NP Full JJ duplex NN . SENT The DT use NN of IN two CD separate JJ communications NNS channels NNS for IN one CD circuit NN . SENT where WRB the DT endpoints NNS are VBP A NP and CC B NP , , one CD channel NN is VBZ transmitted VVN from IN A DT and CC received VVN at IN B NP while IN the DT other JJ channel NN is VBZ transmitted VVN from IN B NP and CC received VVD at IN A DT . SENT FEP NP Front NP End NP Processor NN . SENT A DT dedicated JJ computer NN often RB called VVD a DT communications NNS processor NN , , channel NN attached VVD to TO one CD or CC more JJR host NN computers NNS or CC multi NNS user NN minicomputers NNS and CC performs VVZ data NN communications NNS functions NNS . SENT In IN IBM NP SNA NP networks NNS , , an DT IBM NP 3704 CD , , 3705 CD , , or CC 3725 CD communications NNS processor NN when WRB channel NN attached VVD to TO a DT host NN node NN . SENT Fiber NN Optics NN Transmission NP technology NN where WRB modulated VVN lightwave NN signals NNS , , generated VVN by IN a DT laser NN or CC LED VVD , , are VBP propagated VVN along IN a DT glass NN or CC plastic NN lightguide NN and CC then RB demodulated VVN back RB into IN electrical JJ signals NNS by IN a DT light JJ sensitive JJ receiver NN . SENT File VV server NN In IN Local NP Area NP Networks NPS , , a DT station NN dedicated VVN to TO providing VVG file NN and CC mass NN data NNS storage NN services NNS to TO the DT other JJ stations NNS on IN the DT LAN NP . SENT Filter NP Electronic NP circuitry NN that WDT removes VVZ energy NN in IN unwanted JJ frequencies NNS , , such JJ as IN noise NN , , from IN a DT transmission NN channel NN . SENT may MD be VB analog JJ or CC digital JJ in IN operation NN . SENT FIPS NP Federal NP Information NP Processing NP Standard NP . SENT A DT U NP . SENT S NP . SENT Federal NP Government NP standard JJ procedure NN that WDT must MD be VB met VVN by IN any DT government NN supplier NN . SENT Flag NN In IN data NN communications NNS , , a DT bit NN pattern NN of IN 01111110 CD , , used VVN by IN many JJ bit NN oriented VVN protocols NNS to TO mark VV the DT beginning NN and CC end NN of IN a DT frame NN . SENT Forward RB Error NN Correction NN FEC NP Technique NN for IN correcting VVG errors NNS incurred VVN in IN data NN transmission NN by IN the DT receiving VVG DCE NP . SENT Typically RB involves VVZ a DT convolution NN of IN the DT transmitted JJ bits NNS , , and CC the DT appending VVG of IN extra JJ bits NNS , , using VVG an DT algorithm NN common JJ to TO both CC the DT receiver NN and CC transmitter NN . SENT Accomplished VVN within IN OSI NP layer NN 1 CD and CC independent JJ of IN higher JJR layers NNS . SENT FM JJ Frequency NN modulation NN . SENT Frame NN In IN data NN communications NNS , , a DT group NN of IN bits NNS sent VVN serially RB over IN a DT communications NNS channel NN and CC containing VVG some DT delimitation NN , , address NN and CC control NN information NN . SENT Normally RB associated VVN with IN OSI NP layer NN 2 CD , , i NP . SENT e SYM . SENT frame NN generally RB refers VVZ to TO layer NN 2 CD while IN packet NN generally RB refers VVZ layer NN 3 CD . SENT In IN video NN , , refers VVZ to TO a DT single JJ scanned VVN image NN . SENT Frame NP Check NP Sequence NN FCS NN Used VVN in IN bit NN oriented JJ protocols NNS , , a DT 16 CD bit NN field NN usually RB appended VVN at IN the DT end NN of IN a DT frame NN that WDT contains VVZ transmission NN error NN checking NN information NN . SENT A DT technique NN known VVN as IN Cyclic JJ Redundancy NN Check NP CRC NP is VBZ used VVN to TO compute VV the DT FCS NN and CC the DT term NN CRC NP is VBZ often RB substituted VVN for IN FCS NN . SENT Frame VV Relay VV A DT fast JJ packet NN data NN communications NNS standard JJ that IN segments NNS and CC packetizes VVZ frames NNS data NNS into IN discreet JJ transmission NN units NNS that WDT are VBP routed VVN along IN the DT frame NN relay NN network NN via IN permanent JJ virtual JJ connections NNS . SENT Newer JJR X NN . SENT 25 CD packet NN switches NNS may MD be VB reprogrammed VVN for IN Frame NP Relay NN . SENT Frame NN relay NN is VBZ independent JJ of IN originating VVG protocols NNS . SENT Standardized JJ by IN CCITT NP and CC ANSI NP . SENT Major JJ IXC NP companies NNS offer VVP Frame NP Relay VV switching VVG services NNS . SENT Framing VVG Bit NN A DT bit NN added VVD to TO byte NN interleaved VVD time NN multiplexed JJ data NN streams NNS to TO mark VV the DT beginning NN of IN each DT sequence NN of IN repetitive JJ bytes NNS . SENT Multiple JJ framing NN bit NN patterns NNS provide VVP data NN stream NN synchronization NN . SENT Free NP Space NP Loss NN The DT signal NN loss NN between IN the DT receiver NN and CC the DT transmitter NN of IN a DT radio NN system NN . SENT Calculated VVN by IN the DT formula NN . SENT Loss NN 36 CD . SENT 6 CD 20 CD logD JJ miles NNS 20 CD logf NN MHz NN . SENT Frequency NN The DT number NN of IN repetitions NNS per IN second JJ of IN a DT complete JJ waveform NN normally RB expressed VVD in IN Hertz NP Hz NP . SENT Frequency NN Modulation NN FM NN A DT Method NN of IN placing VVG an DT intelligent JJ signal NN analog NN or CC digital JJ on IN a DT carrier NN wave NN by IN varying VVG the DT frequency NN of IN the DT transmitted JJ signal NN . SENT Frequency NN response NN The DT variation NN in IN relative JJ strength NN measured VVN in IN decibels NNS between IN frequencies NNS in IN a DT given VVN frequency NN band NN . SENT Frequency NN Division NN Multiplexing VVG FDM NP Technique NN for IN sharing VVG a DT transmission NN channel NN wherein RB carrier NN signals NNS of IN different JJ frequencies NNS are VBP transmitted VVN simultaneously RB . SENT FDM NP was VBD widely RB used VVN in IN telephony NN , , especially RB on IN microwave NN radio NN channels NNS until IN the DT mid JJ 1980 CD s PP . SENT Broadcast NN radio NN , , TV NP and CC broadband NP LANs NP are VBP the DT major JJ applications NNS currently RB in IN use NN . SENT FSK NP Frequency NN Shift NN Keying VVG . SENT Sometimes RB called VVN Voice NP Frequency NN Teletype VV VFT NP . SENT An DT early JJ modulation NN technique NN used VVN for IN teletype VV transmission NN over IN voice NN channels NNS . SENT A DT mark NN was VBD represented VVN by IN a DT frequency NN shift NN above IN and CC a DT space NN by IN a DT shift NN below IN the DT carrier NN frequency NN . SENT The DT term NN VFT NP implies VVZ multiplexing VVG several JJ telegraph NN channels NNS onto IN a DT signal NN voice NN channel NN by IN using VVG a DT number NN of IN different JJ carrier NN frequencies NNS . SENT FTP NP File NP Transfer NN Program NN . SENT An DT application NN level NN data NN communications NNS program NN that WDT transfers VVZ files NNS . SENT Files NNS are VBP identified VVN , , located VVN , , segmented VVN , , tagged VVN with IN a DT header NN and CC passed VVD to TO the DT next JJ protocol NN level NN for IN transmission NN . SENT The DT name NN comes VVZ from IN TCP NN but CC the DT function NN is VBZ a DT typical JJ application NN level NN program NN . SENT Full JJ duplex NN FDX NP The DT use NN of IN two CD separate JJ communications NNS channels NNS for IN one CD circuit NN . SENT where WRB the DT endpoints NNS are VBP A NP and CC B NP , , one CD channel NN is VBZ transmitted VVN from IN A DT and CC received VVN at IN B NP while IN the DT other JJ channel NN is VBZ transmitted VVN from IN B NP and CC received VVD at IN A DT . SENT Full JJ motion NN video NN Television NN transmission NN where WRB images NNS are VBP sent VVN and CC displayed VVN in IN real JJ time NN and CC motion NN is VBZ continuous JJ . SENT compare VV with IN freeze NN frame NN . SENT Used VVN in IN all DT broadcast NN TV NN , , whereas IN slow JJ scan NN TV NN is VBZ often RB used VVN in IN conference NN video NN . SENT FX NP Foreign NP Exchange NP . SENT A DT telephony NN term NN for IN an DT exchange NN switch NN outside IN the DT LATA NP . SENT Often RB refers VVZ to TO a DT dedicated JJ leased VVN line NN from IN a DT PBX NP to TO the DT FX NN , , so RB a DT call NN placed VVN to TO the DT FX NN number NN is VBZ answered VVN by IN the DT PBX NP . SENT G NP Top NP G NP Giga NP Prefix NN meaning VVG one CD billion CD e NN . SENT g NN . SENT Gb VV s PP . SENT Gain NN Increased VVD signal NN power NN , , usually RB the DT result NN of IN amplification NN . SENT measured VVN in IN decibels NNS for IN the DT ratio NN of IN an DT output NN signal NN level NN . SENT opposite JJ of IN loss NN , , or CC attenuation NN . SENT Gateway NN An DT actual JJ protocol NN translation NN computer NN or CC logical JJ boundary NN area NN within IN a DT network NN computer NN that WDT serves VVZ to TO interconnect VV data NN communications NNS networks NNS with IN different JJ OSI NP layer NN 4 CD and CC above JJ protocols NNS . SENT See VV Bridge NP and CC Router NN . SENT In IN TCP NN IP NP protocols NNS Gateway NP refers VVZ to TO a DT network NN protocol NN node NN , , often RB called VVN more RBR correctly RB a DT Router NN . SENT Geosynchronous JJ orbit NN The DT position NN where WRB communications NNS satellites NNS will MD remain VV in IN orbit NN over IN the DT same JJ location NN above IN the DT earth's JJ equator NN . SENT An DT orbit NN of IN about IN 23 CD , , 300 CD miles NNS above IN the DT earth's JJ surface NN , , where WRB a DT satellite's JJ orbital NN velocity NN matches VVZ the DT rotation NN of IN the DT earth NN , , causing VVG it PP to TO remain VV stationary JJ relative NN to TO a DT point NN on IN the DT earth NN . SENT Graded VVN index NN A DT type NN of IN optical JJ fiber NN where WRB the DT refractive JJ index NN of IN the DT core NN varies VVZ smoothly RB with IN the DT radius NN . SENT Graded VVN index NN cores NNS are VBP used VVN in IN multi NNS mode NN fibers NNS utilized VVN in IN LAN NP applications NNS . SENT Ground VV An DT electrical JJ connection NN or CC common JJ conductor NN that WDT , , at IN some DT point NN , , connects VVZ to TO the DT earth NN . SENT Ground NN start VVP A DT telephony NN term NN describing VVG a DT signaling VVG method NN where WRB one CD station NN detects VVZ that IN a DT circuit NN is VBZ grounded VVN at IN the DT other JJ end NN . SENT This DT is VBZ opposed VVN to TO Loop NP Start NP which WDT signals VVZ using VVG both DT tip NN ring NN . SENT Ground NN start NN offers VVZ supervision NN , , the DT ability NN to TO transfer VV calls NNS back RB to TO the DT CO NP . SENT Ground NN station NN An DT assemblage NN of IN communications NNS equipment NN , , including VVG signal NN generator NN , , transmitter NN , , receiver NN , , antenna NN , , and CC communications NNS control VVP computers NNS that WDT transmit VV and CC receivers NNS signals NNS to TO from IN a DT communications NNS satellite NN . SENT Also RB earth NN station NN . SENT GSM NP Global NP System NP for IN Mobile NP Communications NPS Service NP . SENT The DT European JJ digital JJ cellular JJ standard NN . SENT GMA NN uses VVZ TDMA NP to TO provide VV 8 CD channels NNS of IN 13 CD kb NN s PP voice VVP on IN an DT 200 CD kHz NN carrier NN channel NN . SENT Setup NN and CC control NN is VBZ also RB TDMA NP . SENT The DT standard NN also RB calls VVZ for IN half DT rate NN service NN using VVG 6 CD . SENT 5 CD kb NN s PP voice VVP to TO provide VV 16 CD channels NNS in IN 200 CD kHz NN . SENT GSM NP therefore RB offers VVZ a DT spectrum NN use NN improvement NN of IN from IN 1 CD . SENT 2 CD to TO 2 CD . SENT 4 CD over IN analog JJ AMPS NNS . SENT To TO this DT GSM NN adds VVZ a DT frequency NN hopping VVG technique NN to TO improve VV access NN . SENT H NP Top NP Half NN duplex NN HDX NP The DT operational JJ of IN a DT communications NNS channel VVP where WRB transmission NN and CC reception NN occurs VVZ in IN both DT directions NNS alternately RB based VVN on IN an DT established JJ channel NN control NN protocol NN . SENT Handshake NN protocol NN In IN communications NNS , , a DT predefined JJ exchange NN of IN signals NNS or CC control NN characters NNS between IN two CD devices NNS or CC nodes NNS that WDT sets VVZ up RP the DT conditions NNS for IN data NN transfer NN or CC transmission NN . SENT also RB , , handshaking JJ . SENT Hard RB wired VVN Referring VVG to TO a DT communications NNS link NN that WDT is VBZ not RB switched VVN and CC is VBZ therefore RB dedicated VVN to TO a DT single JJ set NN of IN users NNS . SENT Harmonic JJ distortion NN Signal NP distortion NN normally RB analog NN caused VVN by IN harmonic JJ frequencies NNS generated VVN from IN the DT interference NN among IN the DT primary JJ signal NN frequencies NNS on IN the DT channel NN . SENT The DT power NN of IN the DT harmonic JJ frequencies NNS is VBZ measured VVN in IN decibels NNS as IN compared VVN to TO the DT power NN of IN the DT input NN signal NN . SENT HDLC NP See NP High NP level NN Data NP Link NN Control NP . SENT HDX NP Half NN duplex NN . SENT Head NN end NN A DT passive JJ component NN in IN a DT broadband NN transmission NN network NN that WDT translates VVZ one CD range NN of IN frequencies NNS transmit VV to TO a DT different JJ frequency NN band NN receive VVP and CC allows VVZ devices NNS on IN a DT single JJ cable NN network NN to TO send VV and CC receive VV , , without IN the DT signals NNS interfering VVG with IN each DT other JJ . SENT Generally RB refers VVZ to TO the DT beginning VVG end NN of IN a DT broadband NN communications NNS system NN . SENT Hertz NP Hz NP The DT unit NN for IN the DT measurement NN of IN frequency NN , , where WRB one CD Hertz NP equals VVZ one CD cycle NN per IN second JJ . SENT High JJ Frequency NN HF NP Portion NN of IN the DT electromagnetic JJ spectrum NN , , typically RB used VVN in IN short JJ wave NN radio NN applications NNS . SENT frequencies NNS approximately RB in IN the DT 3 CD to TO 30 CD MHz NN range NN . SENT High NP Level NP Data NP Link NN Control NP HDLC NP CCITT NP standard NN , , bit NN oriented VVN , , data NNS link VVP control NN protocol NN that WDT is VBZ the DT foundation NN on IN which WDT most JJS other JJ bit NN oriented VVN protocols NNS are VBP based VVN . SENT HDLC NP is VBZ the DT underlying JJ protocol NN of IN ADCCP NP , , DDCPM NP , , SDLC NP , , LAP NN B NN , , and CC LAP VVP D NP . SENT HSSI NP High NP Speed NN Serial JJ Interface NP . SENT A DT DTE NP to TO DCE NP interface NN developed VVD to TO support VV serial JJ speeds NNS up RB to TO 52 CD Mb NN s PP . SENT V NN . SENT 35 CD is VBZ standards NNS limited VVN to TO 6 CD Mb NN s PP and CC RS NP 449 CD 422 CD to TO 10 CD Mb NN s PP . SENT HSSI NP is VBZ the DT defacto NP standard NN for IN DS NP 3 CD STS NP 1 CD interface NN . SENT Uses VVZ a DT 50 CD pin NN connector NN identical JJ to TO a DT SCSI NP external JJ connection NN , , but CC only RB 12 CD pins NNS are VBP identified VVN in IN the DT standard NN . SENT Hybrid JJ In IN telephony NN , , an DT induction NN coil NN and CC related JJ circuitry NN at IN a DT central JJ office NN that IN interfaces NNS a DT two CD wire NN local JJ loop NN to TO a DT four CD wire NN circuit NN , , allowing VVG for IN the DT physical JJ separation NN of IN the DT transmit VV and CC receive VV signals NNS . SENT Hz NP See NP hertz NN . SENT I NP O NP Input NN Output NN . SENT I NP Top NP ICA NN International NP Communications NPS Association NP . SENT A DT major JJ trade NN organization NN for IN large JJ communications NNS users NNS based VVN in IN Dallas NP , , Texas NP . SENT IEEE NP Institute NP of IN Electrical NP and CC Electronics NP Engineers NPS . SENT Impedance NN The DT opposition NN to TO an DT electrical JJ wave NN based VVN on IN frequency NN , , resistance NN , , inductance NN , , and CC capacitance NN . SENT Measured VVN in IN ohms NNS . SENT Impedance NN is VBZ said VVN to TO be VB matched VVN when WRB all DT components NNS of IN a DT communications NNS channel VVP present VV the DT same JJ normally RB standardized JJ average JJ impedance NN to TO the DT communications NNS signal VVP . SENT Infrared JJ Portion NN of IN the DT electromagnetic JJ spectrum NN used VVN for IN optical JJ fiber NN transmission NN and CC also RB for IN short JJ haul NN open JJ air NN data NNS transmission NN . SENT transmission NN wavelengths NNS longer RBR than IN about RB 0 CD . SENT 7 CD microns NNS . SENT The DT band NN is VBZ divided VVN into IN three CD sub NN bands NNS . SENT Near IN Infrared JJ 1 CD . SENT 75 CD micrometers NNS to TO 3 CD micrometers NNS , , Middle JJ Infrared JJ 3 CD micrometers NNS to TO 30 CD micrometers NNS , , Far RB Infrared JJ 30 CD micrometers NNS to TO 1000 CD micrometers NNS . SENT Injection NN Laser NP Diode NN ILD NP Sometimes RB called VVD the DT semiconductor NN diode NN . SENT A DT laser NN in IN which WDT the DT lasing VVG occurs VVZ at IN the DT junction NN of IN the DT n NN type NN and CC p NN type NN semiconductor NN materials NNS . SENT A DT coherent JJ light JJ source NN . SENT Special JJ dopants NNS in IN the DT materials NNS emit VV photons NNS when WRB excited VVN by IN an DT electronic JJ current NN . SENT A DT feedback NN loop NN provides VVZ the DT lasing VVG effect NN . SENT Integrated NP Digital NP Network NP IDN NP The DT integration NN of IN transmission NN , , switching VVG and CC protocols NNS into IN a DT circuit NN switched VVD data NN network NN . SENT Refers VVZ to TO networks NNS other JJ than IN ISDN NP . SENT Interoffice JJ trunk NN A DT direct JJ circuit NN between IN telephone NN central JJ offices NNS . SENT ISDN NP Integrated NP Services NPS Digital NP Network NP . SENT A DT set NN of IN standards NNS developed VVN by IN CCITT NP to TO define VV a DT global JJ public JJ access NN voice NN data NNS network NN for IN the DT 21 CD st NP century NN . SENT The DT future JJ telephone NN network NN . SENT The DT 1988 CD CCITT NP standards NNS release NN makes VVZ possible JJ to TO manufacture VV of IN hardware NN for IN network NN implementation NN . SENT Broadband NP and CC International NP standards NNS will MD be VB implemented VVN in IN the DT 1990 CD s PP . SENT ISO NP International NP Standards NPS Organization NP . SENT Performs VVZ ANSI NP functions NNS internationally RB . SENT Isochronous JJ Transmission NP A DT method NN of IN synchronous JJ transmission NN where WRB the DT timing NN relationship NN between IN the DT transmitter NN and CC the DT receiver NN is VBZ maintained VVN by IN the DT clock NN rate NN of IN marks NNS on IN the DT transmission NN path NN . SENT Timing NN is VBZ passed VVN from IN one CD transmitter NN to TO the DT next JJ . SENT Used VVN in IN DS NP 1 CD related JJ signals NNS . SENT IXC NP Inter NP eXchange NN Carrier NP . SENT Any DT carrier NN registered VVN with IN the DT FCC NP that WDT is VBZ authorized VVN to TO carry VV customer NN transmissions NNS between IN LATAs NP interstate JJ or CC , , if IN approved VVN by IN a DT state NN public JJ utility NN commission NN , , intrastate JJ . SENT Examples NNS . SENT AT IN T NN Communications NP , , MCI NP , , U NP . SENT S NP . SENT Sprint NP , , WillTel NP , , and CC so RB on IN . SENT J NP Top NP Japanese NP Digital NP Cellular NP JDC NP The DT Japanese JJ digital JJ cellular JJ telephone NN standard NN . SENT JDC NP uses VVZ TDMA NP to TO provide VV 3 CD channels NNS of IN 8 CD kb NN s PP voice VVP over IN a DT 25 CD kHz NN carrier NN channel NN providing VVG a DT spectrum NN use NN improvement NN of IN 3 CD . SENT 6 CD over IN AMPS NNS . SENT Jitter VV The DT slight JJ movement NN of IN a DT transmission NN signal NN in IN time NN or CC phase NN that WDT can MD introduce VV errors NNS and CC loss NN of IN synchronization NN for IN high JJ speed NN synchronous JJ communications NNS . SENT Jumper NP A NP wire NN or CC cable NN used VVN to TO establish VV a DT circuit NN , , often RB temporarily RB , , for IN testing NN or CC diagnostics NNS . SENT K NP Top NP K NP kilo NN Notation NN for IN one CD thousand CD e NN . SENT g NN . SENT , , kilobit NN s PP . SENT k NN Expression NN representing VVG a DT Kilo NN or CC 1000 CD . SENT In IN Hertz NP , , kHz NP 1000 CD Hz NP . SENT In IN data NN storage NN a DT k NN 1 CD , , 024 CD , , or CC 2 CD to TO the DT 10 CD th NN power NN . SENT A DT Kbyte NP of IN memory NN 1 CD , , 0204 CD bytes NNS of IN computer NN memory NN . SENT Ka NP band NN Portion NN of IN the DT electromagnetic JJ spectrum NN . SENT frequencies NNS approximately RB in IN the DT 12 CD to TO 30 CD GHz NP range NN . SENT Kb NP s PP Kilobits NP per IN second JJ . SENT A DT standard JJ measure NN of IN data NN rate NN and CC transmission NN capacity NN . SENT Key JJ Telephone NP System NP KTS NP In IN telephony NN . SENT a DT Key JJ station NN or CC key JJ telephone NN equipment NN . SENT Describing VVG multiline NN telephone NN equipment NN . SENT A DT telephone NN system NN that WDT offers VVZ multiple JJ access NN to TO 2 CD to TO 12 CD trunk NN lines NNS , , and CC 4 CD to TO 40 CD extensions NNS . SENT Originally RB this DT equipment NN was VBD electromechanical JJ , , leased VVN from IN AT IN T NN and CC required VVD 25 CD pair NN cable NN to TO connect VV it PP . SENT It PP has VHZ been VBN functionally RB replaced VVN by IN low JJ cost NN , , 3 CD pair NN electronic JJ equipment NN . SENT Ku NP band NN Portion NN of IN the DT electromagnetic JJ spectrum NN , , being VBG used VVN increasingly RB for IN satellite NN communications NNS . SENT frequencies NNS approximately RB in IN the DT 10 CD to TO 12 CD GHz NP range NN . SENT L NP Top NP L NP band NN Portion NN of IN the DT electromagnetic JJ spectrum NN commonly RB used VVN in IN satellite NN and CC microwave NN applications NNS , , with IN frequencies NNS approximately RB in IN the DT 1 CD GHz NP region NN . SENT LAN NP Local NP Area NP Network NP LAP NN Link NN Access NP Procedure NN . SENT A DT term NN used VVN to TO describe VV a DT data NN link NN level NN used VVN for IN packet NN switched VVD networks NNS . SENT The DT CCITT NP X NP . SENT 25 CD packet NN switch VVP standard JJ uses NNS LAP VVP B NP LAP NN Balanced VVN and CC LAP VVP D NP is VBZ standardized JJ for IN use NN on IN the DT ISDN NP D NP channel NN . SENT LATA NP Local NP Access NP and CC Transport NP Area NP . SENT Defined VVN as IN part NN of IN the DT AT IN T NN Bell NP system NN breakup NN 1983 CD one CD of IN 161 CD local JJ telephone NN serving VVG areas NNS in IN the DT United NP States NPS . SENT A DT Local NP Exchange NP Company NP LEC NP has VHZ the DT exclusive JJ rights NNS to TO operate VV within IN a DT LATA NP , , subject JJ to TO the DT state NN PUC NP regulations NNS . SENT Any DT inter VV LATA NP communications NNS must MD be VB transferred VVN to TO an DT Inter NP eXchange NN Company NP IXC NP . SENT LASER NN An DT acronym NN for IN Light NP Amplification NN by IN Stimulated VVN Emission NN of IN Radiation NN , , a DT device NN which WDT transmits VVZ an DT extremely RB narrow JJ and CC coherent JJ beam NN of IN electromagnetic JJ energy NN in IN the DT visible JJ light JJ spectrum NN . SENT Primary JJ light JJ signal NN source NN for IN optical JJ fiber NN transmission NN . SENT Leased VVN line NN A DT dedicated JJ circuit NN , , typically RB supplied VVN by IN the DT local JJ exchange NN company NN . SENT The DT term NN applies VVZ to TO any DT voice NN , , data NNS , , modem NN or CC FAX NP circuit NN either CC Off IN Premises NNS Extension NP OPX NP , , Foreign NP Exchange NP , , Tie NN line NN , , T NN 1 CD or CC trunk NN circuit NN . SENT Light JJ Emitting VVG Diode NN LED VVD A DT semiconductor NN device NN that WDT emits VVZ incoherent JJ light NN formed VVN by IN the DT P NN N NP function NN . SENT Light JJ intensity NN is VBZ roughly RB proportional JJ to TO electrical JJ current JJ flow NN . SENT A DT principal JJ light JJ source NN for IN optical JJ fiber NN transmission NN used VVN mainly RB with IN multimode NN fiber NN . SENT Lightwave NN Referring VVG to TO electromagnetic JJ wavelengths NNS in IN the DT region NN of IN visible JJ light NN . SENT wavelengths NNS of IN approximately RB 0 CD . SENT 8 CD to TO 1 CD . SENT 6 CD microns NNS . SENT referring VVG to TO the DT technology NN of IN fiber NN optic NN transmission NN . SENT Line NN Refers VVZ to TO a DT channel NN or CC telephone NN line NN . SENT Line NN Overhead NN In IN SONET NP . SENT part NN of IN the DT transmission NN overhead NN , , between IN major JJ equipment NN such JJ as IN multiplexer NN to TO DXC NP , , mux NNS to TO mux NNS , , etc FW . SENT Provides VVZ timing NN alignment NN and CC protection NN switching NN . SENT See VV Section NP Path NP Link NN layer NN The DT logical JJ entity NN in IN the DT OSI NP model NN concerned VVN with IN transmission NN of IN data NNS between IN adjacent JJ network NN nodes NNS . SENT Dee NP data NNS link NN . SENT Loading VVG coil NN An DT induction NN device NN employed VVN in IN telephone NN local JJ loops NNS , , generally RB those DT exceeding VVG 18 CD , , 000 CD feet NNS in IN length NN , , that WDT compensates VVZ for IN the DT wire NN capacitance NN by IN adding VVG inductance NN . SENT Local JJ Area NP Network NP LAN NP Local NP Area NP Network NP . SENT A DT data NN network NN with IN transmission NN media NNS optimized VVN for IN high JJ speed NN , , short JJ distance NN , , multiple JJ access NN applications NNS . SENT Typical JJ applications NNS are VBP PC NN to TO PC NN , , PC NN to TO mini NN or CC PC NN to TO mainframe NN . SENT LAN NP standards NNS are VBP provided VVN by IN IEEE NP 802 CD . SENT X SYM documentation NN . SENT Local JJ Exchange NP Company NP LEC NP Local NP Exchange NP Company NP . SENT Name NN for IN the DT telephone NN company NN in IN which WDT local JJ service NN of IN your PP$ telephone NN is VBZ connected VVN . SENT Provides VVZ the DT first JJ level NN of IN connection NN to TO the DT Public NP Switched VVD Telephone NP Network NP PSTN NP . SENT Prior RB to TO 1996 CD was VBD protected VVN by IN law NN from IN competition NN in IN a DT specific JJ franchise NN area NN . SENT Local JJ Loop NP In IN telephony NN , , the DT wire NN pair NN that WDT connects VVZ a DT subscriber NN to TO a DT phone NN company NN central JJ office NN or CC remote JJ . SENT Typically RB operating VVG at IN 48 CD volts NNS with IN a DT 20 CD Hz NP 70 CD volt NN ring NN signal NN and CC limited VVN to TO a DT 5 CD mi NN length NN . SENT Logical JJ Link NN Control NP LLC NP A DT protocol NN standardized JJ by IN the DT IEEE NP 802 CD . SENT 2 CD common JJ to TO all DT LAN NP applications NNS and CC used VVN for IN data NNS link VVP level NN transmission NN control NN . SENT LLC NP works VVZ with IN the DT Media NP Access NP Control NP MAC NN protocols NNS . SENT Logical JJ Unit NP LU NP In IN IBM's NP SNA NP , , a DT logical JJ port NN through IN which WDT a DT user NN gains NNS access NN to TO the DT services NNS of IN a DT network NN . SENT Loop NN start NN In IN telephony NN , , a DT local JJ loop NN that WDT signals VVZ an DT off JJ hook NN condition NN by IN allowing VVG DC NP current JJ flow NN between IN the DT tip NN and CC ring NN conductors NNS . SENT Loop NN start NN is VBZ common JJ for IN single JJ line NN telephones NNS . SENT Loopback NP A NP testing NN procedure NN commonly RB in IN telecommunications NNS , , normally RB on IN full JJ duplex NN FDX NP channels NNS , , in IN which WDT a DT test NN message NN is VBZ sent VVN to TO the DT far JJ end NN of IN the DT channel NN and CC then RB resent VVP back RB to TO the DT originator NN and CC compared VVN with IN the DT original JJ test NN transmission NN . SENT Noise NN , , distortion NN , , signal NN loss NN , , BER NP etc FW . SENT can MD be VB determined VVN by IN loopback NN testing NN . SENT Loopback NP testing NN requires VVZ manual JJ or CC computer NN control NN patch NN panels NNS in IN order NN to TO connect VV test NN generation NN and CC measurement NN equipment NN to TO the DT channel NN and CC to TO establish VV the DT far JJ end NN loopback NN . SENT Loss NN Reduction NN in IN signal NN strength NN , , expressed VVN in IN decibels NNS . SENT also RB attenuation NN . SENT LRC NP Longitudinal JJ Redundancy NN Check NP . SENT Part NN of IN the DT original JJ Block NP Check NP Character NN BCC NP based VVN on IN longitudinal JJ and CC vertical JJ parity NN . SENT M NP Top NP M NP Mega NP The DT designation NN for IN one CD million CD e NN . SENT g NN . SENT Mb NP s PP . SENT M NP bit NN An DT X NN . SENT 25 CD feature NN , , or CC facility NN , , that WDT notifies VVZ the DT receiver NN all DT data NNS from IN the DT sender NN or CC transport NN layer NN entity NN has VHZ been VBN transmitted VVN . SENT MAC NN Media NP Access NP Control NP . SENT The DT lower JJR sublayer NN of IN the DT IEEE NP 802 CD . SENT X SYM defined VVN link NN layer NN , , which WDT complements VVZ the DT Logical JJ Link NN Control NP LLC NP . SENT This DT is VBZ a DT media NN specific JJ access NN control NN protocol NN within IN IEEE NP 802 CD specifications NNS and CC includes VVZ variations NNS for IN the DT token JJ ring NN , , token JJ bus NN , , and CC CSMA NP CD NP . SENT MAC NN deals NNS with IN the DT electrical JJ signals NNS and CC access NN protocols NNS of IN 802 CD . SENT X SYM networks NNS . SENT MAN NN Metropolitan NP Area NP Network NP . SENT A DT carrier NN operated VVD , , high JJ speed NN , , easily RB accessed VVN data NN network NN operating NN within IN a DT LATA NP . SENT See NP DQDB NP . SENT Main JJ Distributing NN Frame NP MDF NP In IN telephony NN , , a DT board NN containing VVG many JJ punch NN blocks NNS where WRB telephone NN PBX NP subscriber NN lines NNS are VBP terminated VVN and CC interconnected VVN by IN patch NN wires NNS . SENT Manchester NP encoding VVG Digital NP line NN encoding VVG technique NN in IN which WDT a DT transition NN occurs VVZ in IN the DT middle NN of IN each DT bit NN period NN . SENT a DT negative JJ to TO positive JJ voltage NN transition NN of IN the DT bit NN period NN designates VVZ a DT binary JJ 1 CD , , while IN a DT positive JJ to TO negative JJ transition NN represents VVZ a DT 0 CD . SENT Primarily RB used VVN on IN coaxial JJ wire NN systems NNS . SENT This DT encoding VVG technique NN also RB allows VVZ for IN network NN clocking VVG from IN the DT line NN frequency NN . SENT Differential JJ Manchester NP coding VVG , , used VVN on IN Token JJ Ring NP networks NNS over IN twisted JJ pair NN , , is VBZ nearly RB identical JJ except IN a DT relative NN as RB opposed VVN to TO absolute JJ change NN in IN phase NN indicates VVZ a DT binary JJ 1 CD . SENT MAP NN Manufacturing NP Automation NN Protocol NP . SENT A DT network NN under IN development NN by IN major JJ U NP . SENT S NP . SENT manufacturers NNS with IN the DT objective NN of IN combining VVG factory NN management NN and CC robotics NNS into IN an DT integrated JJ computer NN manufacturing NN process NN . SENT MAP NN utilizes VVZ the DT Token JJ Bus NP LAN NP technology NN . SENT Matrix NN In IN switch NN technology NN . SENT That DT portion NN of IN the DT switch NN architecture NN where WRB input NN and CC output NN are VBP physically RB interconnected VVN . SENT Megabyte NN Mbyte NN The DT basic JJ unit NN of IN measurement NN of IN mass JJ data NNS storage NN , , equal JJ to TO 1 CD , , 024 CD Kbytes NNS . SENT Message NN switching VVG A DT statistical JJ multiplex NN and CC switching VVG technique NN of IN storing VVG messages NNS today NN data NN packets NNS on IN hard JJ disk NN and CC , , after IN selecting VVG the DT proper JJ outgoing JJ channel NN , , placing VVG the DT message NN in IN queue NN for IN retransmitting VVG it PP toward IN its PP$ destination NN . SENT Micron NN Micrometer NN . SENT One CD millionth NN of IN a DT meter NN . SENT Microprocessor NN An DT electronic JJ integrated JJ circuit NN , , typically RB a DT single JJ chip NN package NN , , capable JJ of IN receiving VVG and CC executing VVG coded VVN instructions NNS e NN . SENT g NN . SENT , , INTEL NP 80286 CD , , 80386 CD , , Motorola NP 68000 CD are VBP popular JJ microprocessors NNS . SENT Microsecond NN One CD millionth NN of IN a DT second NN . SENT Microwave NN Portion NN of IN the DT electromagnetic JJ spectrum NN above IN about RB 890 CD megahertz NN . SENT Also RB describing VVG a DT line NN of IN sight NN open JJ air NN radio NN transmission NN of IN a DT radio NN beam NN of IN energy NN within IN the DT microwave NN frequency NN band NN used VVN as IN a DT carrier NN for IN multiple JJ communications NNS channels NNS . SENT Millisecond NN One NN thousandth JJ of IN a DT second NN . SENT MIPS NP Million NP Instructions NNS Per IN Second NP . SENT A DT general JJ comparison NN gauge NN of IN CPU NN raw JJ processing NN power NN . SENT Modem NN Modulator NN demodulator NN . SENT A DT Digital NP to TO Analog NP D NP A NP or CC A DT D NP converter NN that WDT alters VVZ a DT carrier NN signal NN to TO represent VV a DT binary JJ 1 CD or CC 0 CD . SENT A DT simple JJ example NN is VBZ On IN Off IN keying VVG , , where WRB the DT presence NN of IN the DT carrier NN signal NN is VBZ equal JJ to TO a DT 1 CD . SENT However RB , , any DT signal NN property NN s PP , , frequency NN , , phase NN , , amplitude NN , , may MD be VB used VVN . SENT Modems NNS are VBP used VVN over IN telephone NN wire NN lines NNS and CC other JJ transmission NN media NNS . SENT Modified JJ Huffman NP Code NP A DT common JJ data NN compression NN technique NN . SENT Modulation NN The DT process NN of IN placing VVG intelligence NN , , represented VVN by IN either CC an DT analog JJ wave NN or CC a DT digital JJ code NN , , on IN a DT transmission NN path NN . SENT Normally RB accomplished VVN by IN varying VVG a DT characteristic NN of IN a DT carrier NN wave NN in IN accordance NN with IN another DT signal NN wave NN or CC binary JJ digit NN . SENT In IN analog JJ transmission NN , , Amplitude NN Modulation NN AM NP varies VVZ the DT carrier NN amplitude NN . SENT while IN Frequency NN Modulation NN FM NN varies VVZ the DT frequency NN in IN accordance NN with IN the DT amplitude NN of IN the DT signal NN wave NN . SENT Carrier NN Wave NP CW NP also RB called VVD on IN off IN OOF NN keying VVG and CC phase NN modulation NN are VBP common JJ with IN digital JJ information NN . SENT Modulo NP N NP In IN data NN communications NNS , , refers VVZ to TO a DT quantity NN , , such JJ as IN of IN messages NNS or CC frames NNS , , that WDT can MD be VB counted VVN before IN the DT counter NN resets VVZ to TO zero VV . SENT Often RB referring VVG to TO the DT number NN of IN messages NNS N NP 1 CD that WDT can MD be VB outstanding JJ on IN the DT network NN before IN an DT acknowledgment NN is VBZ required VVN from IN the DT receiver NN . SENT e SYM . SENT g NN . SENT in IN HDLC NP related JJ protocols NNS , , Modulo NP 8 CD 3 CD bit NN counter NN and CC Modulo NP 128 CD 7 CD bit NN counter NN . SENT Morse NP Code NP The DT original JJ character NN code NN used VVN for IN the DT telegraph NN 1841 CD . SENT Morse NN code NN is VBZ composed VVN of IN long JJ dash NN and CC short JJ dot VVP electromagnetic JJ pluses NNS used VVN together RB to TO form VV characters NNS . SENT At IN first RB these DT were VBD actually RB written VVN on IN moving VVG paper NN tape NN . SENT Morse NN code NN became VVD very RB widely RB used VVN for IN radio NN telegraphy NN because IN of IN its PP$ ease NN of IN modulation NN , , but CC was VBD replaced VVN in IN telegraphy NN by IN the DT marks NNS and CC spaces NNS of IN Baudot NP Code NP 1870 CD . SENT MOS NNS Metal NP oxide NN semiconductor NN . SENT A DT semiconductor NN that WDT uses VVZ a DT thin JJ layer NN of IN metal NN oxide NN to TO conduct VV electrons NNS across IN P NN N NP junctions NNS . SENT This DT technique NN produces VVZ lower JJR heat NN and CC current JJ requirements NNS compared VVN to TO bipolar JJ construction NN , , thereby RB allowing VVG large JJ scale NN integrated JJ circuits NNS . SENT MTBF NP Mean NP time NN between IN failure NN . SENT The DT average JJ time NN between IN reported VVN equipment NN failures NNS . SENT May MD be VB calculated VVN for IN systems NNS by IN the DT formula NN 1 CD MTBF NN 1 LS A DT 1 CD B NN . SENT . SENT . SENT 1 CD X NN . SENT Multidomain NN network NN In IN IBM's NP SNA NP , , a DT network NN consisting VVG of IN two CD or CC more JJR host NN based VVN system NN services NNS control VVP points NNS . SENT typically RB , , a DT network NN with IN more JJR than IN one CD host NN mainframe NN . SENT Multidrop NP A NP communications NNS arrangement NN where WRB multiple JJ devices NNS share NN a DT common JJ transmission NN channel NN , , though RB only RB one PP may MD transmit VV at IN a DT time NN . SENT See VV multipoint NN . SENT Multimode NN In IN optical JJ fiber NN communications NNS , , describing VVG a DT lightguide NN optical JJ fiber NN , , with IN a DT 50 CD or CC 62 CD micron NN core NN capable JJ of IN propagating VVG light JJ signals NNS along IN various JJ paths NNS modes NNS . SENT Such JJ paths NNS modes NNS will MD differ VV in IN time NN delay NN thereby RB causing VVG pulse NN spreading VVG and CC limiting VVG the DT speed NN at IN which WDT the DT lightguide NN may MD be VB modulated VVN . SENT Compare VV with IN single JJ mode NN fiber NN . SENT Multipath NN Fading NN In IN microwave NN radio NN , , signal NN fading NN caused VVN by IN the DT reflection NN of IN part NN of IN the DT radio NN beam NN off RB of IN the DT ground NN in IN such PDT a DT manner NN as RB to TO arrive VV at IN the DT receive VVP antenna NN 180 CD degrees NNS out RB of IN phase NN thereby RB canceling VVG the DT primary JJ signal NN . SENT Multiplexer NN A DT device NN that WDT combines VVZ several JJ communications NNS channels NNS on IN to TO a DT single JJ channel NN of IN higher JJR bandwidth NN or CC line NN speed NN . SENT The DT term NN multiplexer NN commonly RB assumes VVZ both DT multiplexing VVG and CC demultiplexing VVG within IN the DT same JJ device NN . SENT See VV TDM NP and CC FDM NP . SENT Multiplexing VVG The DT combining VVG of IN multiple JJ data NNS channels NNS onto IN a DT single JJ high JJ bandwidth NN transmission NN channel NN . SENT Data NP streams NNS are VBP interleaved VVN on IN bit NN or CC byte NN basis NN Time NP Division NP Multiplexing VVG TDM NN while IN analog JJ signals NNS are VBP frequency NN translated VVN and CC placed VVN on IN a DT high JJ frequency NN carrier NN Frequency NN Division NN Multiplexing VVG FDM NP . SENT Multipoint NN line NN A DT single JJ communications NNS channel VVP typically RB a DT leased VVN telephone NN circuit NN to TO which WDT more JJR than IN one CD station NN is VBZ attached VVN and CC addressed VVN separately RB under IN a DT polling NN protocol NN controlled VVN by IN the DT master NN station NN or CC computer NN . SENT Mux NP Multiplexer NN MULDEM NP Multiplexer NN Demultiplexer NP Mu NP Law NP A DT speech NN companding NN algorithm NN used VVN for IN North NP American NP DS NP 0 CD PCM NP . SENT N NP Top NP Nanometer NP nm NN One CD billionth NN of IN a DT meter NN . SENT Nanosecond NN One CD billionth NN of IN a DT second NN . SENT Narrowband NP AMPS NNS NAMPS NN Designed VVN by IN Motorola NP as IN an DT interim JJ technique NN before IN digital JJ cellular JJ , , NAMPS NP used VVD a DT 10 CD kHz NN analog JJ voice NN channel NN instead RB of IN the DT 30 CD kHz NN uses VVZ in IN AMPS NNS . SENT It PP provides VVZ the DT same JJ spectrum NN use NN improvement NN as IN AMPS NNS but CC requires VVZ added JJ processing NN to TO maintain VV channel NN quality NN . SENT NAMPS NP degrades VVZ data NN capacity NN . SENT NATA NP North NP American NP Telecommunications NPS Association NP . SENT A DT trade NN association NN of IN telephone NN equipment NN suppliers NNS distributors NNS . SENT Trade NN show NN called VVN UNICOM NP . SENT NAU NP Network NP Addressable JJ Unit NN . SENT In IN SNA NP , , the DT combination NN of IN a DT logical JJ unit NN LU NP and CC a DT physical JJ unit NN PU NP that WDT allows VVZ the DT use NN of IN the DT SNA NP network NN services NNS . SENT NBS NP National NP Bureau NP of IN Standards NPS . SENT U NP . SENT S NP . SENT government NN agency NN that WDT maintains VVZ standards NNS , , operates VVZ WWV NP time NN station NN and CC distributes VVZ the DT Data NP Encryption NN Standard NP . SENT NETVIEW NP Trade NP name NN given VVN IBM's NP network NN management NN software NN package NN . SENT NETVIEW NP runs VVZ on IN IBM NP mainframes NNS using VVG SNA NP but CC will NN interface NN network NN equipment NN supplied VVN by IN many JJ manufacturers NNS . SENT NetWare NN Trade NP name NN given VVN to TO Novell's NP LAN NP software NN packages NNS . SENT Novell NP is VBZ the DT industry NN leader NN in IN LAN NP software NN . SENT Network NN A DT group NN of IN nodes NNS voice NN or CC data NN terminals NNS interconnected VVN by IN a DT series NN communications NN channels NNS . SENT through IN an DT assortment NN of IN modems NNS , , multiplexers NNS , , and CC transmission NN equipment NN . SENT Network NN Address VV A DT binary JJ address NN , , usually RB translated VVN from IN human JJ language NN by IN a DT communications NNS computer NN , , that WDT is VBZ placed VVN within IN the DT network NN call NN packet NN or CC datagram NN and CC allows VVZ that IN packet NN or CC datagram NN to TO find VV its PP$ intended JJ node NN . SENT The DT number NN of IN bits NNS required VVN will MD depend VV on IN the DT number NN of IN nodes NNS and CC sub NN networks NNS interconnected VVN . SENT CCITT NP X NP . SENT 400 CD seeks VVZ to TO find VV a DT global JJ data NN network NN addressing VVG system NN . SENT Your PP$ telephone NN number NN with IN country NN and CC area NN code NN is VBZ a DT global JJ voice NN network NN address NN . SENT Network NP Layer NP OSI NP layer NN 3 CD responsible JJ for IN routing VVG data NNS through IN the DT network NN . SENT Network NP Management NP System NP A DT comprehensive JJ system NN of IN equipment NN used VVN in IN monitoring NN , , controlling VVG , , and CC managing VVG a DT data NN communications NNS network NN . SENT Usually RB consists VVZ of IN testing NN devices NNS , , CRT NP displays NNS and CC printers NNS , , patch NN panels NNS , , and CC circuitry NN for IN diagnostics NNS and CC reconfiguration NN of IN channels NNS , , generally RB housed VVN together RB in IN an DT operator NN console VV unit NN . SENT The DT location NN of IN the DT network NN management NN system NN is VBZ often RB called VVN the DT Network NP Control NP Facility NP NCF NP . SENT Network NN Topology NN Describing VVG the DT physical JJ and CC logical JJ relationship NN of IN nodes NNS in IN a DT network NN . SENT the DT schematic JJ arrangement NN of IN the DT links NNS and CC nodes NNS of IN a DT network NN IBM NP . SENT networks NNS are VBP typically RB of IN either CC a DT star NN , , ring NN , , tree NN , , or CC bus NN topology NN , , or CC some DT hybrid JJ combination NN thereof RB . SENT Node NP A DT point NN where WRB one NN or CC more JJR functional JJ units NNS interconnect NN transmission NN lines NNS ISO NP . SENT A DT physical JJ device NN that WDT allows VVZ for IN the DT transmission NN of IN data NNS within IN a DT network NN . SENT an DT end NN point NN of IN a DT link NN or CC a DT function NN common JJ to TO two CD or CC more JJR links NNS in IN a DT network NN , , typically RB includes VVZ host NN processors NNS , , communications NNS controllers NNS , , cluster NN controllers NNS , , and CC terminals NNS . SENT Noise NN weighting NN A DT method NN of IN assigning VVG a DT specific JJ value NN , , in IN numerical JJ readings NNS , , to TO the DT transmission NN impairment NN due JJ to TO the DT noise NN encountered VVD by IN an DT average JJ user NN operating VVG a DT particular JJ class NN of IN telephone NN subset NN . SENT Noise NN Weighting NN has VHZ been VBN established VVN by IN the DT agencies NNS concerned VVN with IN public JJ telephone NN service NN . SENT They PP represent VVP successive JJ stages NNS of IN technological JJ development NN . SENT Non JJ blocking VVG In IN switching VVG , , describing VVG matrix NN through IN which WDT a DT traffic NN path NN always RB exists VVZ for IN each DT attached VVN station NN . SENT Generically RB , , a DT switch NN or CC switching VVG environment NN designed VVN never RB to TO experience VV a DT busy JJ condition NN due JJ to TO call VV volume NN . SENT NT NP 1 CD Network NP Termination NN type NN 1 CD . SENT In IN ISDN NP the DT principal JJ network NN to TO customer NN interface NN . SENT It PP is VBZ a DT rough JJ equivalent NN of IN a DT CSU NP . SENT Terminates VVZ the DT digital JJ subscriber NN loop NN and CC interfaces NNS to TO the DT CPE NN . SENT NT NP 2 CD Network NP Termination NN type NN 2 CD . SENT In IN ISDN NP a DT specified JJ interface NN to TO an DT NT JJ 1 CD from IN multiple JJ user NN CPE NN . SENT Normally RB , , the DT NT JJ 2 CD will MD be VB contained VVN within IN the DT PBX NP or CC other JJ customer NN node NN . SENT The DT NT JJ 2 CD provides VVZ local JJ address NN resolution NN and CC contention NN functions NNS . SENT Nyquist NP theorem NN In IN communications NNS theory NN , , states NNS that IN two CD samples NNS per IN cycle NN is VBZ sufficient JJ to TO characterize VV a DT band NN limited VVN analog JJ signal NN . SENT in IN other JJ words NNS , , the DT sampling NN rate NN must MD be VB twice RB the DT highest JJS frequency NN component NN of IN the DT signal NN e NN . SENT g NN . SENT , , sampling VVG at IN 8 CD kHz NN for IN a DT 4 CD kHz NN analog JJ signal NN . SENT O NP Top NP Object NN code NN Executable JJ machine NN code NN , , programs NNS that WDT have VHP been VBN compiled VVN or CC assembled VVN . SENT compare VV with IN source NN code NN . SENT OCR NP Optical NP Character NN Recognition NP . SENT the DT process NN of IN reading VVG characters NNS by IN scanning VVG text NN and CC converting VVG it PP into IN machine NN readable JJ digital JJ codes NNS , , OEM NP Original JJ Equipment NP Manufacturer NN . SENT The DT maker NN of IN equipment NN marketed VVN by IN another DT vendor NN , , usually RB under IN the DT name NN of IN the DT reseller NN . SENT The DT OEM NP may MD manufacture VV certain JJ components NNS , , or CC complete JJ systems NNS . SENT Off IN hook NN In IN telephony NN , , condition NN indicating VVG the DT active JJ state NN of IN a DT subscriber's JJ telephone NN circuit NN . SENT a DT line NN state NN that WDT signals VVZ a DT central JJ office NN that IN a DT user NN requires VVZ service NN . SENT opposite JJ of IN on IN hook NN . SENT Off IN line NN Condition NN in IN which WDT user NN , , terminal NN , , or CC other JJ device NN is VBZ not RB connected VVN to TO a DT computer NN , , or CC is VBZ not RB actively RB transmitting VVG via IN a DT network NN . SENT operation NN of IN a DT functional JJ unit NN without IN the DT continual JJ control NN of IN a DT computer NN . SENT compare VV with IN on IN line NN . SENT Office NN class NN Functional JJ ranking NN of IN a DT telephone NN network NN switching VVG center NN depending VVG on IN transmission NN requirements NNS and CC hierarchical JJ relationship NN to TO other JJ switching VVG centers NNS . SENT see VV Class NP X NP central JJ office NN . SENT On IN hook NN Deactivated VVD condition NN of IN a DT subscriber's JJ telephone NN circuit NN , , where WRB the DT telephone NN or CC circuit NN is VBZ not RB in IN use NN . SENT opposite JJ of IN off JJ hook NN . SENT On IN line NN Condition NN in IN which WDT a DT user NN , , terminal NN , , or CC other JJ device NN is VBZ actively RB connected VVN with IN the DT facilities NNS of IN a DT communications NNS network NN or CC computer NN . SENT pertaining VVG to TO the DT operation NN of IN a DT functional JJ unit NN that WDT is VBZ under IN the DT continual JJ control NN of IN a DT computer NN . SENT opposite JJ of IN off JJ line NN . SENT Operating VVG System NP OS NN The DT software NN of IN a DT computer NN that WDT controls VVZ the DT execution NN of IN programs NNS , , typically RB handling VVG the DT functions NNS of IN input NN output NN control NN , , resource NN scheduling NN , , and CC data NNS management NN e NN . SENT g NN . SENT , , CP NP M NP , , MS NN DOS NNS , , VM NP 370 CD , , UNIX NP . SENT Optical JJ fiber NN Any DT filament NN or CC fiber NN , , made VVN of IN dielectric JJ materials NNS used VVN to TO transmit VV laser NN or CC LED VVD generated VVN light JJ signals NNS . SENT Optical JJ fiber NN usually RB consists VVZ of IN a DT core NN , , which WDT carries VVZ the DT signal NN , , and CC cladding NN , , a DT substance NN with IN a DT slightly RB higher JJR refractive JJ index NN than IN the DT core NN , , which WDT surrounds VVZ the DT core NN and CC serves VVZ to TO reflect VV the DT light JJ signal NN back RB into IN it PP . SENT also RB , , lightguide NN . SENT OPX NN Off IN Premises NNS Extension NP . SENT An DT extension NN not RB located VVN in IN the DT same JJ area NN as IN a DT PBX NP . SENT the DT Local NP Exchange NP Company NP LEC NP provides VVZ a DT dedicated JJ leased VVN pair NN from IN the DT PBX NP location NN to TO the DT distant JJ location NN , , normally RB within IN the DT same JJ LATA NP . SENT Oscillator NN An DT electronic JJ device NN used VVN to TO produce VV repeating JJ signals NNS of IN a DT given VVN amplitude NN or CC frequency NN . SENT OS NN See VV operating VVG system NN . SENT OSI NP Open NP Systems NPS Interconnection NN . SENT Referring VVG to TO an DT International NP Standards NPS Organization NP ISO NP conceptional JJ model NN for IN data NN communications NNS protocols NNS . SENT The DT OSI NP reference NN model NN provides VVZ a DT logical JJ structure NN for IN data NN communications NNS network NN standards NNS . SENT The DT OSI NP model NN is VBZ based VVN on IN a DT seven CD layer NN architecture NN . SENT 1 CD Physical NP , , 2 CD Data NP Link NN , , 3 CD Network NP , , 4 CD Transport NN 5 CD Session NP , , 6 CD Presentation NP 7 CD Application NN . SENT Comment NN . SENT While IN an DT OSI NP standard JJ data NN communications NNS architecture NN may MD never RB materialize VV , , all DT future JJ data NN communications NNS standards NNS will MD be VB based VVN on IN the DT logical JJ approach NN of IN the DT OSI NP model NN . SENT Overhead RB In IN communications NNS , , all DT information NN , , such JJ as IN control NN , , routing VVG , , and CC error NN checking NN characters NNS , , in IN addition NN to TO user NN transmitted JJ data NNS . SENT includes VVZ information NN that WDT carries VVZ network NN status NN or CC operational JJ instructions NNS , , network NN routing NN information NN , , and CC retransmissions NNS of IN user NN data NNS messages NNS that WDT are VBP received VVN in IN error NN . SENT P NN Top NP PABX NP Private NP Automatic NP Branch NP Exchange NP . SENT See NP PBX NP . SENT Note NN . SENT Electronic NP Private NP Branch NP Exchange NP EPBX NP and CC Computerized JJ Branch NP Exchange NP CBX NP are VBP all DT identical JJ terms NNS . SENT Packet NN A DT group NN of IN bits NNS arranged VVN with IN a DT sync NN character NN s PP address VVP , , control NN , , message NN data NNS , , frame NN check NN sum NN and CC ending VVG flag NN . SENT The DT term NN packet NN is VBZ usually RB associated VVN with IN a DT network NN frame NN , , where WRB the DT address NN is VBZ the DT network NN address NN of IN the DT sender NN and CC receiver NN and CC control NN information NN is VBZ related VVN to TO the DT network NN as RB opposed VVN to TO the DT data NN link NN . SENT The DT network NN packet NN may MD contain VV combined VVN or CC segmented VVN data NN link NN frames NNS . SENT The DT packet NN can MD be VB sent VVN along IN a DT network NN , , stored VVN and CC forwarded VVN . SENT The DT term NN was VBD developed VVN with IN X NP . SENT 25 CD standard NN and CC applies VVZ to TO other JJ packet NN networks NNS . SENT Paper NN tape NN A DT system NN once RB used VVN to TO form VV a DT permanent JJ record NN of IN transmitted VVN and CC received VVN data NNS in IN telecommunications NN centers NNS by IN punching NN holes NNS representing VVG data NNS codes NNS , , normally RB Baudot NP , , on IN paper NN tape NN . SENT This DT technology NN became VVD obsolete JJ with IN advent NN of IN reliable JJ magnetic JJ storage NN media NNS in IN the DT 1960 CD s PP . SENT Parallel JJ processing NN Concurrent JJ or CC simultaneous JJ execution NN of IN two CD or CC more JJR processes NNS or CC programs NNS , , within IN the DT same JJ processor NN . SENT compare VV with IN serial JJ or CC sequential JJ processing NN . SENT Parallel JJ data NNS transmission NN A DT type NN of IN data NN transfer NN in IN which WDT all DT bits NNS of IN a DT byte NN or CC computer NN word NN are VBP sent VVN simultaneously RB during IN one CD clock NN cycle NN , , either CC over IN separate JJ conductors NNS or CC multiplexed VVN over IN a DT single JJ channel NN . SENT Parity NN bit NN An DT additional JJ non JJ information NN bit NN appended VVN to TO a DT group NN of IN bits NNS , , typically RB to TO a DT 7 CD or CC 8 CD bit NN byte NN , , which WDT indicates VVZ whether IN the DT number NN of IN ones NNS in IN the DT group NN is VBZ an DT odd JJ or CC even JJ number NN . SENT A DT basic JJ and CC elementary JJ mechanism NN for IN error NN checking NN . SENT Parity NN check NN Process NN of IN error NN checking NN using VVG the DT parity NN bit NN . SENT varied JJ methods NNS include VVP longitudinal JJ parity NN check NN and CC vertical JJ parity NN check NN . SENT Path NN The DT connection NN between IN two CD communicating VVG devices NNS . SENT Path NN Availability NN The DT calculation NN of IN the DT availability NN of IN a DT microwave NN radio NN path NN expressed VVN in IN the DT percentage NN of IN time NN per IN year NN the DT path NN is VBZ available JJ to TO the DT user NN . SENT This DT considers VVZ radio NN propagation NN only RB . SENT Thus RB , , a DT path NN with IN an DT availability NN of IN 99 CD . SENT 9999 NP has VHZ a DT propagation NN outage NN of IN . SENT 0001 CD X NP 525 CD , , 960 CD min NN yr NN . SENT 5 LS . SENT 26 CD minutes NNS yr NN . SENT Path NP Control NP layer NN In IN IBM's NP SNA NP , , the DT network NN processing NN layer NN that WDT handles VVZ primarily RB the DT routing NN of IN data NN units NNS as IN they PP travel VVP through IN the DT network NN and CC manages VVZ share NN link NN resources NNS . SENT Path NN Overhead NN In IN SONET NP . SENT the DT overhead JJ user NN device NN first JJ optical JJ mux NNS to TO user NN device NN . SENT Placed VVN in IN SPE NN , , it PP identifies VVZ the DT payload NN by IN trace VV number NN and CC contents NNS . SENT See VV Line NP Overhead JJ Section NN Overhead NN . SENT PBX NP Private NP Branch NP Exchange NP . SENT A DT telephone NN switch NN located VVN on IN a DT customer's NNS premises NN that WDT provides VVZ voice NN grade NN circuits NNS with IN advanced JJ features NNS for IN the DT local JJ premises NNS , , and CC is VBZ connected VVN to TO LEC NP and CC IXC NP service NN providers NNS by IN trunk NN access NN lines NNS , , and CC may MD also RB be VB connected VVN with IN other JJ PBX NP switches NNS over IN tie NN lines NNS . SENT Numerous JJ other JJ enhanced JJ features NNS , , such JJ as IN least JJS cost NN routing NN and CC call NN detail NN recording NN are VBP available JJ . SENT The DT PBX NP is VBZ the DT major JJ equipment NN requirement NN for IN a DT private JJ voice NN network NN . SENT Also RB called VVN Electronic NP PBX NP EPBX NP and CC Computer NP PBX NP CBPX NP . SENT PCM NP Pulse NP Code NP Modulation NN . SENT The DT primary JJ standard NN for IN voice NN digitization NN . SENT Based VVN on IN the DT Nyquist NP theorem NN , , the DT 0 CD 4000 CD Hz NP telephone NN voice NN signal NN amplitude NN is VBZ sampled VVN at IN twice RB its PP$ highest JJS frequency NN 8000 CD samples NNS second JJ and CC each DT sample NN value NN is VBZ assigned VVN an DT 8 CD bit NN binary JJ value NN . SENT At IN the DT receiver NN , , the DT samples NNS are VBP read VVN and CC converted VVN back RB to TO analog JJ voltages NNS which WDT are VBP passed VVN through IN a DT low JJ pass NN filter NN to TO recreate VV the DT original JJ voice NN analog NN signal NN . SENT PCM NP signal NN is VBZ comprised VVN of IN 8000 CD 8 CD bit NN bytes NNS per IN second JJ or CC 64 CD kb NN s PP . SENT Personal NP Communications NPS Network NP PCN NP See NP Personal NP Communications NPS Service NP . SENT Personal NP Communications NPS Service NP PCS NP The DT ability NN to TO provide VV PBX NP features NNS to TO a DT widely RB moving VVG Cellular NP Telephone NP . SENT This DT would MD include VV telephone NN , , voice NN mail NN , , FAX NP and CC Page NP services NNS to TO one CD instrument NN with IN plug NN in IN accessories NNS . SENT If IN this DT could MD be VB integrated VVN with IN office NN and CC residence NN wire NN telephone NN services NNS it PP would MD form VV the DT ultimate JJ PCN NN . SENT Phase NN jitter NN In IN telephony NN , , the DT measurement NN , , in IN degrees NNS out IN of IN phase NN , , that IN an DT analog JJ signal NN deviates NNS form VVP the DT referenced VVN phase NN of IN the DT main JJ data NNS carrying VVG signal NN . SENT often RB caused VVN by IN alternating VVG current JJ components NNS in IN a DT telecommunications NN network NN . SENT Phase NN modulation NN A DT data NN transmission NN encoding VVG method NN wherein RB the DT phase NN angle NN of IN the DT carrier NN wave NN is VBZ varied VVN to TO represent VV different JJ bit NN values NNS to TO the DT receiver NN . SENT Typically RB eight CD phase NN angles NNS are VBP used VVN to TO represent VV 3 CD bits NNS per IN phase NN shift NN . SENT Phase NN Shift NN Keying VVG PSK NP Phase NN modulation NN encoding VVG technique NN employed VVN by IN many JJ modems NNS . SENT See VV phase NN modulation NN . SENT Physical JJ layer NN Within IN the DT OSI NP model NN , , the DT lowest JJS level NN of IN network NN processing NN . SENT This DT level NN is VBZ concerned VVN with IN the DT electrical JJ , , mechanical JJ , , and CC handshaking JJ procedures NNS over IN the DT interface NN that WDT connects VVZ a DT device NN to TO a DT transmission NN medium NN . SENT Some DT physical JJ layer NN standards NNS are VBP RS NP 232 CD or CC V NN . SENT 21 CD . SENT Physical NP Unit NP PU NP In IN IBM's NP SNA NP , , the DT component NN that WDT manages VVZ and CC monitors VVZ the DT resources NNS of IN a DT node NN , , such JJ as IN attached JJ links NNS and CC adjacent JJ link NN stations NNS . SENT PU NP types NNS follow VVP the DT same JJ classification NN as IN node NN types NNS . SENT see VV node NN types NNS . SENT Picosecond NP One CD trillionth NN of IN a DT second NN . SENT one CD millionth NN of IN a DT microsecond NN . SENT Picture NN Element NN pel NP The DT smallest JJS discrete JJ scanning VVG line NN sample NN of IN a DT facsimile JJ system NN containing VVG only RB black JJ white JJ information NN . SENT PIN NN diode NN A DT device NN used VVN to TO convert VV optical JJ signals NNS to TO electrical JJ signals NNS in IN a DT lightwave NN receiver NN . SENT For IN relatively RB fast JJ speeds NNS and CC moderate JJ sensitivity NN in IN the DT 0 CD . SENT 75 CD micron NN to TO 1 CD . SENT 1 CD micron NN area NN wavelength NN , , the DT silicon NN photodiode NN is VBZ most RBS commonly RB used VVN . SENT Avalanche NN photodiodes VVZ APD NP combine VV the DT detection NN of IN optical JJ signals NNS with IN internal JJ amplification NN of IN the DT current JJ produce NN . SENT The DT internal JJ gain NN is VBZ realized VVN through IN avalanche NN multiplications NNS of IN carriers NNS in IN the DT junction NN region NN . SENT The DT advantage NN in IN using VVG an DT APD NP is VBZ its PP$ higher JJR signal NN to TO noise NN ratio NN , , especially RB at IN high JJ bit NN rates NNS . SENT Point NN of IN Presence NN POP NP In IN telephony NN , , the DT physical JJ access NN location NN within IN a DT LATA NP of IN a DT IXC NP . SENT the DT point NN to TO which WDT the DT local JJ telephone NN company NN terminates VVZ subscribers NNS circuits NNS for IN the DT IXC NP . SENT Commonly RB , , a DT distribution NN frame NN connected VVN to TO a DT lightwave NN transmission NN system NN . SENT Polarity NN Any DT condition NN where WRB there EX are VBP two CD opposing JJ charges NNS , , such JJ as IN positive JJ and CC negative JJ . SENT Polling NN A DT data NN communications NNS control NN procedure NN where WRB a DT master NN station NN systematically RB invites VVZ tributary JJ stations NNS on IN a DT multipoint NN circuit NN to TO transmit VV data NNS . SENT Port NP A DT point NN of IN access NN into IN a DT computer NN , , a DT network NN , , or CC other JJ electronic JJ device NN . SENT The DT physical JJ or CC logical JJ interface NN through IN which WDT one CD gains NNS access NN . SENT Postal NP , , Telegraph NP and CC Telephone NP PTT NP A DT government NN organization NN normally RB European JJ that WDT operates VVZ a DT nationalized VVN public JJ telecommunications NN network NN . SENT See VV CEPT NN . SENT Presentation NP Layer NP In IN the DT OSI NP model NN , , the DT layer NN of IN processing NN that WDT provides VVZ services NNS to TO the DT application NN layer NN , , allowing VVG it PP to TO interpret VV the DT data NN exchange NN and CC to TO structure VV data NN messages NNS to TO be VB transmitted VVN in IN a DT specific JJ display NN and CC control NN format NN . SENT Private JJ line NN A DT leased VVN telephone NN line NN , , attached VVD to TO one CD single JJ user NN . SENT Private JJ network NN A DT network NN established VVN and CC operated VVN by IN a DT private JJ organization NN or CC corporation NN for IN users NNS within IN that DT organization NN or CC corporation NN . SENT A DT private JJ network NN may MD contain VV circuits NNS leased VVN from IN public JJ carriers NNS . SENT Propagation NN delay VV The DT time NN it PP takes VVZ a DT signal NN , , composed VVN of IN electromagnetic JJ energy NN , , to TO travel VV from IN one CD point NN to TO another DT over IN a DT transmission NN channel NN . SENT normally RB the DT speed NN of IN light JJ delay NN through IN open JJ air NN or CC a DT vacuum NN , , or CC a DT slightly RB decreased VVN speed NN depending VVG on IN the DT propagation NN characteristics NNS of IN the DT transmission NN medium NN . SENT Protocol NP Formal JJ set NN of IN rules NNS governing VVG the DT format NN , , timing NN , , sequencing NP , , and CC error NN control NN of IN data NN exchange NN across IN a DT data NN network NN . SENT Note NN that IN many JJ protocols NNS may MD be VB required VVN and CC used VVN on IN a DT single JJ network NN . SENT The DT OSI NP model NN outlines VVZ a DT protocol NN for IN each DT layer NN . SENT Protocol NP Data NP Unit NP PDU NP Information NP delivered VVD as IN a DT unit NN between IN peer NN entities NNS layers NNS of IN an DT OSI NP network NN containing VVG protocol NN control NN information NN . SENT Pseudoternary JJ Coding VVG A DT data NNS encoding VVG technique NN used VVN in IN basic JJ access NN ISDN NP . SENT This DT is VBZ bipolar JJ alternate JJ space NN negative JJ inversion NN . SENT Replaced VVN in IN the DT U NP . SENT S NP . SENT by IN 2 CD B NN 1 CD Q NP coding VVG . SENT Public NP Data NP Network NP PDN NP A DT packet NN switched VVD data NN network NN publicly RB available JJ to TO subscribers NNS . SENT The DT term NN is VBZ more RBR commonly RB used VVN outside IN the DT United NP States NPS . SENT In IN the DT U NP . SENT S NP . SENT examples NNS would MD be VB Telenet NP or CC Compuserve NP etc NN . SENT packet NN network NN services NNS . SENT Public JJ network NN Generically RB , , a DT network NN established VVN and CC operated VVN by IN communications NNS common JJ carriers NNS or CC telecommunications NN administrators NNS for IN the DT provision NN of IN circuit NN switched VVD , , packet NN switched VVD , , and CC leased VVN line NN circuits NNS to TO the DT public NN . SENT compare VV with IN private JJ network NN . SENT Public NP Switched VVD Telephone NP Network NP PSTN NP The DT public JJ telephone NN network NN . SENT The DT term NN is VBZ more RBR commonly RB applied VVN outside IN the DT United NP States NPS . SENT In IN the DT U NP . SENT S NP . SENT both DT LEC NP and CC IXC NP carriers NNS combine VVP to TO form VV the DT PSTN NP . SENT Q NP Top NP Quadrature NN Amplitude NN Modulation NN QAM NP A NP modulation NN technique NN , , using VVG variations NNS in IN both DT signal NN amplitude NN and CC phase NN . SENT This DT technique NN allows VVZ up RP to TO 128 CD data NNS encoded VVD symbols NNS to TO be VB represented VVN per IN hertz NN and CC is VBZ used VVN in IN high JJ density NN digital JJ microwave NN radio NN and CC modem NN applications NNS . SENT Commonly RB implemented VVN as IN 64 CD QAM NP . SENT Queuing VVG In IN telecommunications NNS , , a DT feature NN that WDT allows VVZ calls NNS or CC packets NNS to TO be VB held VVN or CC delayed VVN at IN the DT origination NN switch NN while IN waiting VVG for IN a DT channel NN to TO become VV available JJ . SENT R NP Top NP Rayleigh NP scattering NN Scattering NN caused VVN by IN submicroscopic JJ particle NN fluctuation NN in IN material NN density NN causing VVG minute JJ changes NNS in IN refractive JJ index NN . SENT Reference NN noise NN The DT level NN of IN circuit NN noise NN that WDT will MD produce VV a DT measured VVN reading NN equal JJ to TO that DT produced VVN by IN 1 CD picowatt NN 90 CD dBm NN of IN electric JJ power NN at IN 1 CD , , 000 CD Hz NP . SENT Refractive JJ index NN The DT ratio NN of IN light JJ velocity NN in IN a DT vacuum NN to TO its PP$ velocity NN in IN the DT transmitting VVG medium NN . SENT Remote JJ Operations NP Service NP Element NN ROSE VVD A DT sub NN layer NN program NN within IN layer NN 7 CD of IN the DT OSI NP protocol NN . SENT Repeater NN In IN digital JJ transmission NN , , equipment NN that WDT receives VVZ a DT pulse NN train NN , , regenerates VVZ and CC retimes VVZ it PP , , and CC then RB reconstructs VVZ the DT signal NN for IN retransmission NN . SENT Response NN time NN For IN interactive JJ sessions NNS , , the DT elapsed VVN time NN between IN the DT end NN of IN an DT inquiry NN and CC the DT beginning NN of IN the DT response NN . SENT the DT interval NN between IN a DT user NN data NN entry NN and CC the DT reply NN from IN a DT CPU NN or CC destination NN device NN . SENT Return NN to TO Zero NP RZ NP A DT convention NN in IN digital JJ line NN coding VVG that IN returns NNS the DT signal NN voltage NN to TO a DT zero CD level NN after IN slightly RB more JJR than IN one CD half NN bit NN time NN . SENT See VV Non JJ Return NN Zero NP NRZ NP . SENT Ring NP Signal NP In IN telephony NN , , a DT 20 CD Hz NP , , 40 CD 105 CD volt NN 70 CD v NN . SENT typical JJ signal NN used VVN for IN on IN hook NN loop NN signaling VVG . SENT Distinctive JJ ringing NN is VBZ possible JJ by IN varying VVG the DT frequency NN within IN a DT 15 CD 68 CD Hz NP range NN . SENT Router NN A DT device NN used VVN to TO interconnect VV data NN communications NNS networks NNS with IN different JJ OSI NP level NN 3 CD protocols NNS . SENT The DT term NN is VBZ generally RB applied VVN to TO a DT device NN that WDT intragrates VVZ router NN and CC bridge NN functions NNS with IN leased VVN service NN interfaces NNS . SENT These DT Routers NNS often RB use VVP Internet NP Protocol NP IP NP to TO route NN datagrams NNS among IN networks NNS . SENT Also RB called VVN Internodal JJ Processors NNS INP NP , , the DT device NN can MD be VB interfaced VVN to TO SNA NP networks NNS and CC have VHP revolutionized VVD corporate JJ network NN design NN . SENT The DT leading JJ manufacturers NNS are VBP Cisco NP Systems NPS and CC Wellfleet NP Inc NP . SENT See VV Bridge NP and CC Gateway NP . SENT RS NP 232 CD D NP An NP EIA NP specified VVD physical JJ interface NN , , with IN associated VVN electrical JJ signaling VVG , , between IN data NN circuit NN terminating VVG equipment NN DCE NN and CC data NN terminal NN equipment NN DTE NP . SENT the DT most RBS commonly RB employed VVN interface NN between IN computers NNS and CC modems NNS . SENT RS NP 422 CD A DT Electrical JJ characteristics NNS of IN balanced JJ voltage NN digital JJ interface NN circuits NNS . SENT Utilizes VVZ the DT RS NP 449 CD interface NN standard NN . SENT RS NP 423 CD A DT Electrical JJ characteristics NNS of IN unbalanced JJ voltage NN digital JJ interface NN circuits NNS . SENT Utilizes VVZ the DT RS NP 449 CD interface NN standard NN . SENT S NP Top NP S NP Interface NP In IN ISDN NP , , the DT interface NN between IN the DT NT JJ 2 CD network NN adapter NN and CC the DT user NN often RB combined VVN with IN the DT T NN interface NN to TO connect VV the DT user NN directly RB to TO the DT NT JJ 1 CD . SENT The DT S NP connector NN is VBZ an DT RJ NP 45 CD connector NN and CC is VBZ considered VVN the DT normal JJ user NN interface NN . SENT Satellite NN communications NNS The DT use NN of IN geostationary JJ orbiting VVG satellites NNS to TO relay VV transmissions NNS from IN one CD sending VVG earth NN station NN to TO another DT , , perhaps RB multiple JJ other JJ , , earth NN stations NNS . SENT Scattering VVG Cause NP of IN lightwave NN signal NN loss NN in IN optical JJ fiber NN transmission NN . SENT diffusion NN of IN a DT light JJ beam NN caused VVN by IN microscopic JJ variations NNS in IN the DT material NN density NN of IN the DT transmission NN medium NN . SENT SDLC NP Synchronous JJ Data NP Link NN Control NP . SENT The DT bit NN oriented VVN IBM NP version NN of IN the DT HDLC NP protocol NN used VVN in IN SNA NP communications NNS . SENT SDN NP See NP Software NP Defined VVD Network NP . SENT Also RB VPN NP . SENT Section NN Overhead NN In IN SONET NP . SENT part NN of IN the DT transmission NN overhead NN , , from IN MUX NP DXC NP to TO Repeater NN and CC from IN Repeater NN to TO Repeater NN . SENT Provides VVZ error NN monitoring NN on IN each DT optical JJ segment NN . SENT See VV Line NP Overhead JJ Path NN Overhead NN Segmentation NN The DT process NN of IN dividing VVG a DT user NN data NN message NN into IN smaller JJR frames NNS , , blocks NNS , , or CC packets NNS for IN transmission NN , , where WRB each DT has VHZ an DT integral JJ sequence NN number NN for IN reassembly NN of IN the DT complete JJ message NN at IN the DT destination NN end NN . SENT Often RB called VVN fragmentation NN . SENT Serial JJ transmission NN The DT sequential JJ transmission NN of IN the DT bits NNS constituting VVG an DT entity NN of IN data NNS over IN a DT data NN circuit NN ISO NP . SENT Serving VVG area NN Region NN surrounding VVG a DT broadcasting NN station NN where WRB signal NN strength NN is VBZ at IN or CC above IN a DT stated JJ medium NN . SENT the DT geographic JJ area NN handled VVN by IN a DT telephone NN central JJ office NN facility NN . SENT generally RB equivalent JJ to TO a DT LATA NP . SENT Service NP Access NP Point NP SAP VV The DT interface NN point NN between IN layers NNS of IN the DT OSI NP model NN where WRB a DT protocol NN entity NN can MD access VV the DT services NNS of IN that DT layer NN . SENT Lower JJR layers NNS provide VVP SAPs NNS for IN the DT use NN of IN higher JJR layers NNS . SENT Session NN A DT connection NN between IN two CD stations NNS that WDT allows VVZ them PP to TO communicate VV ISO NP . SENT the DT time NN period NN that IN a DT user NN engages VVZ in IN a DT dialog NN with IN an DT interactive JJ computer NN . SENT in IN IBM's NP SNA NP , , the DT logical JJ connection NN between IN two CD network NN addressable JJ units NNS NAUs NP . SENT Session NN Layer NP In IN the DT OSI NP model NN , , the DT layer NN responsible JJ for IN binding VVG and CC unbinding VVG logical JJ links NNS between IN end NN users NNS and CC maintaining VVG an DT orderly JJ dialog NN between IN them PP . SENT Shielding VVG Protective JJ enclosure NN surrounding VVG a DT transmission NN medium NN , , such JJ as IN coaxial JJ cable NN , , designated VVN to TO minimize VV electromagnetic JJ leakage NN . SENT Simplex NN One CD way NN data NN transmission NN , , with IN no DT capabilities NNS for IN changing VVG direction NN . SENT Signal VV to TO Noise NN Ratio NN Relationship NN of IN the DT magnitude NN of IN a DT transmission NN signal NN to TO the DT noise NN of IN a DT channel NN . SENT measurement NN of IN signal NN strength NN compared VVN to TO error NN inducing VVG circuit NN noise NN . SENT given VVN in IN decibels NNS . SENT Single JJ mode NN A DT lightguide NN optical JJ fiber NN with IN an DT 8 CD micron NN core NN that WDT allows VVZ only RB one CD light NN path NN . SENT Used VVN in IN nearly RB all DT LEC NP and CC IXC NP applications NNS . SENT Normally RB requires VVZ a DT LASER NN source NN . SENT Current JJ technology NN allows VVZ approximately RB 2 CD Gb NN s PP with IN 35 CD miles NNS between IN repeaters NNS . SENT Single JJ sideband NN transmission NN Type NN of IN radio NN transmission NN where WRB one CD sideband NN of IN the DT carrier NN signal NN is VBZ transmitted VVN while IN the DT other JJ is VBZ suppressed VVN . SENT the DT main JJ carrier NN wave NN itself PP may MD either RB be VB transmitted VVN or CC suppressed VVN . SENT Sliding VVG Window NN A DT method NN of IN flow NN control NN used VVN between IN two CD DCE NP devices NNS that WDT regulates VVZ the DT number NN of IN unacknowledged JJ data NN packets NNS or CC frames NNS on IN the DT network NN . SENT Various JJ network NN protocols NNS have VHP specific JJ techniques NNS regulating VVG the DT window NN size NN . SENT SMDS NP Switched VVD Multimegabit NP Data NP Service NP . SENT Access NN to TO switched VVN data NNS service NN above IN 45 CD Mb NN s PP . SENT Initial JJ service NN will MD be VB accessed VVN by IN dedicated JJ DS NP 3 CD s PP , , later JJR through IN 802 CD . SENT 6 CD MANs VVZ . SENT Switching NN will MD be VB via IN Cell NN Relay NN . SENT SMTP NP Simple JJ Mail NP Transfer NN Program NN . SENT Part NN of IN the DT IP NP protocol NN suite NN , , an DT applications NNS level NN program NN that WDT provides VVZ electronic JJ mail NN services NNS . SENT One CD of IN the DT options NNS that WDT enhances VVZ the DT popularity NN or CC TCP NN IP NP SNA NP See NP Systems NPS Network NP Architecture NP IBM NP . SENT SNMP NP SNMPv NP 2 CD Simple JJ Network NP Management NP Protocol NP Version NP 2 CD . SENT An DT object VVP oriented JJ network NN management NN application NN protocol NN for IN use NN with IN TCP NN IP NP . SENT SNMP NP uses VVZ the DT connectionless JJ UDP NP protocol NN of IN the DT TCP NN IP NP suite NN with IN messages NNS formatted VVN by IN ICMP NP . SENT Objects NNS are VBP also RB available JJ to TO support VV OSI NP networks NNS , , making VVG SNMP NP very RB popular JJ among IN network NN users NNS . SENT Software NN Defined VVD Network NP SDN NP Also RB called VVD Virtual JJ Private NP Network NP VPN NP . SENT An DT offering NN of IN the DT public JJ network NN IXC NP LEC NP , , that WDT gives VVZ users NNS the DT appearance NN of IN a DT private JJ network NN . SENT The DT IXC NP or CC LEC NP allows VVZ the DT user NN access NN to TO partitions NNS within IN their PP$ DACS NP equipment NN so IN the DT user NN can MD reconfigure NN leased VVD circuits NNS within IN the DT public JJ network NN . SENT Network NN management NN information NN is VBZ also RB provided VVN to TO the DT user NN for IN their PP$ circuits NNS . SENT The DT result NN is VBZ a DT network NN that WDT appears VVZ private JJ in IN terms NNS of IN flexibility NN without IN requiring VVG the DT purchase NN of IN nodal JJ multiplex JJ equipment NN . SENT SONET NP Synchronous JJ Optical NP NETwork NN . SENT A DT set NN of IN standards NNS under IN development NN by IN CCITT NP ANSI NP aimed VVD at IN synchronizing VVG the DT information NN carried VVD on IN a DT optical JJ fiber NN network NN . SENT Before IN SONET NP , , optical JJ fiber NN signals NNS were VBD composed VVN of IN asynchronous JJ DS NP 3 CD s PP multiplexed VVD onto IN the DT optical JJ path NN by IN bit NN interleaving VVG . SENT DS NP 3 CD s PP are VBP also RB asynchronous JJ but CC are VBP composed VVN of IN synchronous JJ DS NP 1 CD s PP . SENT SONET NP will MD add VV path NN overhead NN bytes NNS identifying VVG each DT optical JJ system NN input NN , , DS NP 1 CD , , DS NP 3 CD or CC Cell NN . SENT Then RB a DT 125 CD microsecond NN wide JJ and CC 9 CD rows NNS deep JJ frame NN is VBZ constructed VVN , , where WRB the DT first JJ three CD bytes NNS of IN each DT row NN contain VVP , , among IN other JJ overhead NN , , pointers NNS to TO the DT start NN of IN each DT path NN overhead NN byte NN . SENT This DT procedure NN allows VVZ the DT direct JJ extraction NN of IN any DT input NN tributary NN within IN the DT frame NN . SENT SONET NP allows VVZ direct JJ tributary NN switching VVG without IN frame NN disassembly NN or CC electronic JJ demultiplexing NN which WDT is VBZ a DT significant JJ improvement NN over IN DACS NP switching NN . SENT Significant JJ network NN control NN advantages NNS are VBP also RB included VVN in IN the DT overhead JJ bytes NNS . SENT Therefore RB , , IXC NP and CC LEC NP carriers NNS are VBP rapidly RB installing VVG SONET NP equipment NN by IN using VVG the DT technology NN for IN all DT new JJ and CC replacement NN optical JJ equipment NN . SENT Space NP Division NP Switching NP A DT switching VVG term NN for IN a DT circuit NN switch NN . SENT a DT switch NN with IN an DT actual JJ physical JJ path NN through IN the DT matrix NN . SENT This DT may MD be VB time NN shared VVD see VV Time NP Multiplexed NP Switching NP but CC not RB time NN slot NN interchanged VVD . SENT Speed NN of IN light JJ 2 CD . SENT 998 CD x SYM 108 CD meters NNS or CC 186 CD , , 000 CD miles NNS per IN second JJ . SENT SPE NP Synchronous JJ Payload NN Envelope NN . SENT A DT SONET NP term NN for IN the DT data NNS carrying VVG part NN of IN SONET NP frames NNS . SENT The DT SPE NN contains VVZ the DT user NN data NNS and CC Path NN Overhead NN . SENT SSCP NP See NP System NP Services NPS Control NP Point NP . SENT Step VV Index NP A DT lightguide NN optical JJ fiber NN , , the DT core NN of IN which WDT exhibits VVZ a DT uniform JJ refractive JJ index NN . SENT Used VVN for IN single JJ mode NN fibers NNS . SENT Stop VV bit NN In IN asynchronous JJ transmission NN , , the DT last JJ transmission NN element NN in IN each DT character NN , , which WDT permits VVZ the DT receiver NN to TO come VV to TO an DT idle JJ condition NN before IN accepting VVG another DT character NN . SENT Store NP and CC Forward NP Describing VVG operation NN of IN a DT data NN network NN where WRB packets NNS , , messages NNS , , or CC frames NNS are VBP temporarily RB stored VVN within IN a DT network NN node NN before IN they PP are VBP transmitted VVN toward IN the DT destination NN . SENT Subarea NP In IN IBM's NP SNA NP , , a DT type NN 4 CD node NN , , defined VVN by IN a DT communications NNS processor NN 37 CD XX NP and CC its PP$ attached VVN peripheral JJ nodes NNS , , all DT of IN which WDT share NN a DT common JJ subarea NN address NN . SENT Superframe NP A DT group NN of IN 12 CD D NP 4 CD frames NNS used VVN together RB so RB that IN the DT framing NN bits NNS provide VVP a DT synchronization NN pattern NN . SENT Replaced VVN by IN the DT Extended JJ Superframe NN in IN 1983 CD . SENT Synchronous JJ Transmission NP Data NP communications NNS where WRB characters NNS or CC bits NNS are VBP sent VVN at IN a DT fixed JJ rate NN , , with IN the DT transmitting VVG and CC receiving VVG devices NNS synchronized VVN . SENT Significantly RB increases VVZ data NN throughput NN rates NNS . SENT Accomplished VVN by IN sync NN characters NNS , , flags NNS , , or CC digital JJ line NN coding VVG techniques NNS . SENT System NN A DT collection NN of IN components NNS that WDT perform VVP a DT defined VVN function NN , , as RB in IN a DT transmission NN system NN , , or CC a DT computer NN system NN . SENT System NP Gain NP The DT gain NN in IN db NP of IN a DT microwave NN receiver NN transmitter NN calculated VVN algebraically RB by IN adding VVG the DT transmitter NN power NN output NN to TO the DT receiver NN threshold NN . SENT System NP Services NPS Control NP Point NP SSCP NP In IN IBM's NP SNA NP , , a DT host NN based VVN data NN communications NNS subprogram NN that WDT manages VVZ the DT network NN configuration NN , , coordinates VVZ network NN operator NN and CC problem NN determination NN requests NNS , , maintains VVZ network NN address NN and CC mapping NN tables NNS , , and CC provides VVZ directory NN support NN and CC session NN services NNS . SENT Systems NP Network NP Architecture NP SNA NP In IN IBM NP networks NNS , , the DT layered VVN logical JJ structure NN , , formats NNS , , protocols NNS , , and CC procedures NNS that WDT govern VVP data NNS communications NNS and CC information NN exchange NN . SENT T NN Top JJ T NN carrier NN Another DT name NN for IN a DT T NN 1 CD . SENT T NN span VVP A DT telephone NN circuit NN or CC cable NN through IN which WDT a DT T NN carrier NN runs VVZ . SENT T NN 1 CD AT IN T NN term NN for IN a DT digital JJ carrier NN facility NN used VVN to TO transmit VV a DT DS NP 1 CD formatted VVD digital JJ signal NN at IN 1 CD . SENT 544 CD Mb NN s PP . SENT Assumes VVZ the DT use NN of IN two CD pair NN of IN copper NN wires NNS as IN the DT transmission NN medium NN . SENT T NN 1 CD C NP AT IN T NN term NN for IN a DT digital JJ carrier NN facility NN used VVN to TO transmit VV a DT DS NP 1 CD C NP formatted VVD digital JJ signal NN at IN 3 CD . SENT 152 CD Mb NN s PP . SENT Assumes VVZ the DT use NN of IN two CD pair NN of IN copper NN wires NNS as IN the DT transmission NN medium NN . SENT T NN 2 CD AT IN T NN term NN for IN a DT digital JJ carrier NN facility NN used VVN to TO transmit VV a DT DS NP 2 CD formatted VVD digital JJ signal NN at IN 6 CD . SENT 312 CD Mb NN s PP . SENT Assumes VVZ the DT use NN of IN two CD pair NN of IN copper NN wires NNS as IN the DT transmission NN medium NN . SENT TA NP Terminal NN Adapter NN . SENT An DT ISDN NP term NN for IN a DT standard JJ device NN used VVN to TO adapt VV non JJ ISDN NP data NNS equipment NN to TO an DT ISDN NP NT NP . SENT Tandem NP office NN switch VVP A DT telephone NN switching VVG center NN designed VVN to TO switch VV 4 CD wire NN trunks NNS among IN CO NP switches NNS or CC other JJ tandem JJ switches NNS . SENT A DT trunk NN office NN switch NN . SENT Primarily RB used VVN for IN long JJ distance NN service NN by IN IXC NP companies NNS but CC also RB used VVN within IN a DT large JJ LATAs NP to TO route NN calls NNS among IN CO NP switches VVZ . SENT Tariff NN A DT document NN filed VVN by IN a DT regulated JJ telephone NN company NN with IN the DT state NN public JJ utilities NNS commission NN or CC the DT FCC NP in IN order NN to TO establish VV rates NNS charged VVN for IN services NNS offered VVD . SENT A DT regulated JJ utility NN must MD provide VV services NNS to TO all DT who WP request VVP them PP at IN a DT fixed JJ rate NN . SENT The DT tariff NN defines VVZ the DT service NN and CC the DT rate NN . SENT Tariffs NNS are VBP approved VVN by IN a DT PUC NP based VVN on IN a DT formula NN that WDT allows VVZ the DT regulated JJ utility NN a DT certain JJ percentage NN of IN profit NN . SENT Tariffs NNS may MD be VB challenged VVN before IN the DT PUC NP or CC in IN the DT courts NNS . SENT If IN the DT court NN finds VVZ a DT tariff NN unjustified JJ or CC ithe JJ services NNS specified VVN were VBD not RB provided VVN , , the DT utility NN might MD have VH to TO refund VV moneys NNS collected VVN . SENT TCP NN IP NP Transport NP Control NP Protocol NP Internet NP Protocol NP . SENT A DT protocol NN suite NN developed VVN by IN several JJ universities NNS under IN government NN grants NNS that WDT became VVD the DT U NP . SENT S NP . SENT government NN data NNS network NN protocol NN until IN 1990 CD . SENT TCP NN IP NP is VBZ a DT connectionless JJ protocol NN system NN designed VVN to TO work VV with IN a DT very RB wide JJ assortment NN of IN computer NN equipment NN . SENT While IN it PP is VBZ not RB formally RB standardized JJ , , it PP is VBZ widely RB used VVN and CC highly RB developed VVN , , and CC therefore RB , , very RB popular JJ with IN private JJ organizations NNS . SENT Despite IN the DT U NP . SENT S NP . SENT government's JJ formal JJ announcement NN of IN its PP$ intent NN to TO switch VV to TO OSI NP protocols NNS , , TCP NN IP NP is VBZ the DT fastest JJS growing VVG network NN protocol NN in IN terms NNS of IN new JJ network NN users NNS . SENT OSI NP has VHZ adopted VVN many JJ of IN the DT features NNS of IN TCP NN IP NP , , but CC the DT protocol NN remains VVZ attractive JJ because IN of IN its PP$ ease NN of IN implementation NN . SENT TDM NP See NP Time NP Division NP Multiplexing VVG . SENT Time NP Division NP Multiple JJ Access NP TDMA NP A DT multiple JJ access NN technique NN where WRB multiple JJ users NNS of IN a DT radio NN channel NN share NN the DT channel NN by IN time NN usage NN . SENT Messages NNS are VBP always RB digital JJ and CC transmitted VVN in IN frames NNS . SENT Transmission NP time NN slots NNS are VBP controlled VVN by IN a DT master NN station NN either CC from IN a DT reference NN frame NN or CC from IN a DT echo NN of IN transmitted JJ frames NNS reclocked VVN by IN the DT master NN station NN . SENT Used VVN as IN a DT multiple JJ access NN technique NN in IN satellite NN and CC cellular JJ telephone NN systems NNS . SENT Telco NP Telephone NP central JJ office NN , , in IN most JJS usage NN . SENT but CC also RB , , generic JJ abbreviation NN for IN the DT telephone NN company NN or CC LEC NP . SENT Telecommunications NP Access NP Method NN TCAM NP A DT widely RB employed VVN communications NNS management NN software NN package NN from IN IBM NP that WDT runs VVZ on IN IBM NP 370 CD and CC compatible JJ mainframes NNS . SENT depending VVG on IN version NN and CC options NNS , , can MD support VV either DT SNA NP or CC pre NP SNA NP networking NN . SENT supplanted VVN by IN VTAM NP in IN recent JJ years NNS , , especially RB where WRB networks NNS are VBP primarily RB SNA NP . SENT Telephony NN Generic JJ term NN describing VVG voice NN telecommunications NNS . SENT Teleprocessing VVG Remote JJ access NN data NNS processing VVG ISO NP . SENT the DT use NN of IN data NNS link VVP communications NNS to TO accomplish VV a DT computer NN based VVN task NN . SENT distinguished VVN from IN distributed VVN data NNS processing VVG DDP NP , , where WRB remote JJ communications NNS are VBP not RB a DT prerequisite NN to TO all DT processing NN . SENT Teletypewriter NN Generic JJ term NN for IN a DT teleprinter NN terminal NN . SENT Teletype VV is VBZ a DT trademark NN of IN Teletype VV Corporation NP . SENT Telex NN Teleprinter NN exchange NN . SENT a DT worldwide RB switched VVN message NN exchange NN service NN , , characterized VVN by IN Baudot NP coded VVN data NNS though IN numerous JJ conversion NN facilities NNS are VBP now RB available JJ , , provided VVN worldwide RB by IN Western NP Union NP in IN the DT United NP States NPS . SENT Teletext NN A DT one CD way NN information NN retrieval NN service NN normally RB provided VVN by IN a DT cable NN TV NN channel NN with IN a DT special JJ decoder NN that WDT allows VVZ page NN selection NN from IN a DT computer NN . SENT Terminated VVN line NN A DT telephone NN circuit NN with IN an DT impedance NN of IN 600 CD ohms NNS and CC terminated VVN with IN a DT load NN having VHG the DT characteristics NNS of IN a DT standard JJ telephone NN set NN . SENT Tie NN line NN A DT leased VVN or CC private JJ dedicated JJ telephone NN circuit NN connecting VVG two CD PBX NP switches NNS . SENT Also RB known VVN as IN an DT interswitch NN trunk NN . SENT Time NN Compression NN Multiplexing VVG TCM NP A DT technique NN of IN time NN multiplexing VVG both DT the DT transmit VV and CC receive VV channel NN on IN one CD path NN using VVG a DT ping NN pong NN system NN of IN sending VVG frames NNS . SENT Used VVN for IN the DT ISDN NP Basic NP Access NP 2 CD B NP D NP . SENT Replaced VVN within IN the DT U NP . SENT S NP . SENT by IN the DT 2 CD B NN 1 CD Q NP procedure NN . SENT Time NP Division NP Multiplexing VVG TDM NP Interleaving VVG digital JJ data NNS from IN many JJ users NNS onto IN one CD two CD serial JJ communications NNS link VVP by IN dividing VVG channel NN capacity NN into IN time NN slices NNS . SENT Example NN DS NP 1 CD Time NP Multiplexed NP Switching NP TMS NP In IN space NN division NN switching VVG circuit NN switching NN where WRB , , under IN computer NN control NN , , the DT path NN through IN the DT matrix NN is VBZ time NN configured VVN for IN each DT TDM NP code NN word NN . SENT Used VVN in IN nearly RB all DT digital JJ telephone NN switches NNS . SENT Timeout NN Expiration NN of IN predefined JJ time NN period NN , , at IN which WDT time NN some DT specified JJ action NN occurs VVZ . SENT in IN communications NNS , , timeouts NNS are VBP employed VVN to TO avoid VV unnecessary JJ delays NNS and CC improve VV traffic NN flow NN . SENT used VVN , , for IN example NN , , to TO specify VV maximum JJ response NN times NNS to TO polling NN and CC addressing VVG , , before IN a DT procedure NN is VBZ automatically RB restarted VVN . SENT Time NP Slot NP Interchange VV TSI NP A DT switching VVG technique NN where WRB the DT TDM NP PCM NP channels NNS are VBP moved VVN in IN time NN between IN the DT input NN and CC output NN TDM NN data NN streams NNS . SENT This DT technique NN requires VVZ that IN each DT input NN data NN stream NN , , normally RB a DT DS NP 1 CD , , be VB buffered VVN , , then RB DO VVP 0 CD s NN are VBP interchanged VVN among IN various JJ DS NP 1 CD s PP . SENT Currently RB used VVN as IN initial JJ and CC final JJ stages NNS on IN large JJ switches NNS combined VVN with IN a DT TMS NP matrix NN . SENT Also RB , , the DT technology NN used VVN for IN DACS NP equipment NN . SENT TMS NP See NP Time NP Multiplexed NP Switching NP . SENT Token JJ Bus NN A DT local JJ network NN access NN media NNS and CC topology NN in IN which WDT all DT stations NNS actively RB attached VVN to TO the DT bus NN listen VVP for IN the DT broadcast NN token JJ or CC supervisory JJ frame NN . SENT stations NNS wishing VVG to TO transmit VV must MD receive VV the DT token JJ before IN doing VVG so RB . SENT however RB , , the DT next JJ physical JJ station NN to TO transmit VV is VBZ not RB necessarily RB the DT next JJ physical JJ station NN on IN the DT bus NN . SENT bus NN access NN is VBZ controlled VVN by IN preassigned JJ priority NN algorithms NNS . SENT Defined VVN by IN IEEE NP 802 CD . SENT 4 LS . SENT Token JJ Ring NP A DT local JJ network NN media NNS access NN control NN and CC topology NN in IN which WDT a DT supervisory JJ frame NN or CC token JJ is VBZ passed VVN from IN station NN to TO station NN in IN sequential JJ order NN . SENT stations NNS wishing VVG to TO gain VV access NN to TO the DT network NN must MD wait VV for IN the DT token JJ to TO arrive VV before IN transmitting VVG data NNS . SENT in IN a DT token JJ ring NN , , the DT next JJ logical JJ station NN receiving VVG the DT token JJ is VBZ also RB the DT next JJ physical JJ station NN on IN the DT ring NN . SENT compare VV with IN token JJ bus NN . SENT Defined VVN by IN IEEE NP 802 CD . SENT 5 CD . SENT Touch NP Tone NP Registered VVD AT IN T NN trademark NN for IN push NN button NN dialing NN . SENT see VV DTMF NP . SENT Transaction NN In IN data NN communications NNS , , a DT message NN destined VVN for IN an DT application NN program NN . SENT a DT computer NN processed JJ task NN that WDT accomplishes VVZ a DT particular JJ action NN or CC result NN . SENT in IN interactive JJ communications NNS , , an DT exchange NN between IN a DT terminal NN and CC another DT device NN , , usually RB a DT computer NN . SENT in IN batch NN or CC remote JJ job NN entry NN , , a DT job NN or CC job NN step NN . SENT Transceiver NN Generic JJ term NN describing VVG any DT device NN , , usually RB a DT terminal NN , , that WDT can MD both CC transmit VV and CC receive VV . SENT Transmission NP The NP dispatching VVG of IN a DT signal NN , , message NN , , or CC other JJ form NN of IN intelligence NN by IN wire NN , , radio NN , , telegraphy NN , , telephony NN , , facsimile NN , , or CC other JJ means NNS ISO NP . SENT a DT series NN of IN characters NNS , , messages NNS or CC blocks NNS , , including VVG control NN information NN and CC user NN data NNS . SENT the DT signaling VVG of IN data NNS over IN communications NNS channels NNS . SENT Transponder NN In IN satellite NN communications NNS , , the DT circuitry NN that WDT receives VVZ an DT up RB link NN signal NN , , translates VVZ it PP to TO another DT , , usually RB higher JJR , , frequency NN , , amplifies VVZ it PP , , and CC then RB retransmits VVZ it PP as IN the DT down JJ link NN signal NN . SENT Transport NP Layer NP In IN the DT OSI NP model NN , , the DT network NN processing NN entity NN responsible JJ , , in IN conjunction NN with IN the DT underlying JJ network NN , , data NNS link VVP , , a DT physical JJ layer NN , , for IN end NN to TO end VV control NN of IN transmitted JJ data NNS and CC the DT optimized VVN use NN of IN network NN resources NNS . SENT Trunk NN A DT dedicated JJ aggregate JJ telephone NN circuit NN connecting VVG two CD switching VVG centers NNS , , central JJ offices NNS , , or CC data NN concentration NN devices NNS . SENT Trunk NN exchange NN A DT telephone NN exchange NN dedicated VVN primarily RB to TO interconnecting VVG trunks NNS . SENT Trunk NN group NN Multiple JJ trunk NN circuits NNS between IN the DT same JJ two CD switching NN centers NNS that WDT can MD be VB accessed VVN by IN dialing VVG a DT single JJ trunk NN number NN and CC use VV the DT same JJ multiplexing VVG equipment NN at IN both DT ends NNS . SENT TSI NP See NP Time NP Slot NP Interchange VV . SENT TTL NN Transistor NN to TO transistor NN logic NN . SENT TTY NP transmission NN Teletypewriter NN communications NNS . SENT generally RB , , basic JJ asynchronous JJ ASCII NP coded VVN data NN communications NNS . SENT U NP Top NP UDP NP User NP Datagram NP Protocol NP . SENT A DT connectionless JJ datagram NN protocol NN that WDT is VBZ an DT option NN to TO TCP NN protocol NN for IN use NN with IN IP NP . SENT Used VVN with IN SMTP NP . SENT UHF NP Ultra JJ High NP Frequency NN . SENT The DT portion NN of IN the DT electromagnetic JJ spectrum NN ranging VVG from IN about RB 300 CD MHz NN to TO about IN 3 CD GHz NP . SENT the DT frequency NN band NN that WDT includes VVZ television NN channels NNS 14 CD through IN 83 CD , , and CC cellular JJ radio NN frequencies NNS . SENT UNI NN User NP Network NP Interface NP . SENT The DT term NN applied VVD to TO a DT user NN interface NN to TO ATM NN services NNS . SENT Belcore NP currently RB is VBZ looking VVG to TO a DT specification NN within IN SMDS NP for IN the DT UNI NN for IN ATM NN services NNS . SENT See VV ATM NN and CC SMDS NP . SENT USART NP Universal NP synchronous JJ asynchronous JJ receiver NN transmitter NN . SENT An DT integrated JJ circuitry NN common JJ to TO many JJ data NNS communications NNS devices NNS . SENT converts VVZ data NNS in IN parallel JJ form NN , , the DT CPU NN into IN serial JJ form NN for IN transmission NN . SENT USRT NP Universal NP synchronous JJ receiver NN transmitter NN . SENT An DT integrated JJ circuit NN that WDT performs VVZ conversion NN of IN parallel JJ data NNS to TO serial JJ form NN for IN transmission NN over IN a DT synchronous JJ data NN channel NN . SENT Ultraviolet JJ Portion NN of IN the DT electromagnetic JJ spectrum NN between IN the DT short JJ wavelength NN extreme NN of IN the DT visible JJ spectrum NN about IN 0 CD . SENT 4 CD microns NNS and CC 0 CD . SENT 04 CD microns NNS . SENT Unbalanced VVN to TO ground VV With IN a DT two CD wire NN circuit NN , , where WRB the DT impedance NN to TO ground VV on IN one CD wire NN is VBZ measurably RB different JJ from IN that DT on IN the DT other JJ . SENT compare VV with IN balanced JJ to TO ground NN . SENT Unix NP Bell NP Laboratories NPS trademark NN for IN a DT computer NN operating NN system NN designated VVN for IN telecommunications NNS and CC multi NNS user NN environments NNS , , developed VVN by IN Bell NP Laboratories NPS . SENT a DT popular JJ multi NNS user NN operating NN system NN for IN 32 CD bit NN computers NNS . SENT V NN Top NP VAN NP Value NP added VVD network NN . SENT A DT data NNS network NN that WDT sells VVZ services NNS to TO the DT public NN . SENT GTE NP Telenet NP and CC Timenet NP are VBP primary JJ examples NNS . SENT VHF NP Very JJ High NP Frequency NN . SENT portion NN of IN the DT electromagnetic JJ spectrum NN with IN frequencies NNS between IN approximately RB 30 CD to TO 300 CD MHz NN . SENT operating VVG band NN for IN television NN channels NNS 2 CD to TO 13 CD and CC most RBS FM JJ radio NN . SENT Vertical JJ redundancy NN check NN VCR NP A NP parity NN check NN performed VVN on IN each DT character NN of IN an DT ASCII NP block NN as IN the DT block NN is VBZ received VVN . SENT Videotex NP An DT interactive JJ data NN communications NNS applications NNS designated VVN to TO allow VV unsophisticated JJ users NNS to TO converse VV with IN a DT remote JJ database NN , , enter VV data NNS for IN transactions NNS , , and CC retrieve VV textual JJ and CC graphics NNS information NN for IN display NN on IN subscriber NN television NN sets VVZ of IN typically RB lower JJR cost NN terminals NNS . SENT Virtual JJ Circuit NN In IN packet NN switching NN , , network NN facilities NNS that WDT give VVP the DT appearance NN to TO the DT user NN of IN an DT actual JJ end NN to TO end VV circuit NN . SENT in IN contrast NN to TO a DT physical JJ circuit NN , , a DT dynamically RB visitable JJ network NN connection NN where WRB sequential JJ user NN data NN packets NNS may MD be VB routed VVN differently RB during IN the DT course NN of IN a DT virtual JJ connection NN . SENT enables VVZ transmission NN facilities NNS to TO be VB shared VVN by IN many JJ virtual JJ circuits NNS simultaneously RB . SENT Virtual JJ storage NN The DT concept NN of IN storage NN space NN that WDT may MD be VB viewed VVN as IN addressable JJ main JJ storage NN to TO a DT computer NN user NN , , but CC is VBZ actually RB auxiliary JJ storage NN usually RB peripheral JJ mass NN storage NN mapped VVN into IN real JJ addresses NNS . SENT amount NN of IN virtual JJ storage NN is VBZ limited VVN by IN the DT addressing VVG scheme NN of IN the DT computer NN . SENT VPN NP Virtual JJ Private NP Network NP . SENT An DT IXC NP service NN now RB offered VVN by IN LECs NP , , that WDT allows VVZ the DT customer NN to TO program NN portions NNS of IN the DT carrier's JJ DACS NP equipment NN to TO define VV the DT connections NNS and CC bandwidth NN required VVN by IN the DT customer NN . SENT To TO some DT extent NN VPNs NNS allow VVP the DT customer NN bandwidth NN on IN demand NN as RB well RB as IN alternate JJ routing NN and CC network NN management NN information NN . SENT A DT VPN NP brings VVZ with IN it PP far RB more JJR flexibility NN and CC reliability NN than IN a DT truly RB private JJ network NN , , because IN the DT customer NN has VHZ the DT use NN of IN the DT carrier's NNS resources NNS . SENT Also RB called VVN SDN NP . SENT Voice NP Frequency NN VF NP Describing VVG an DT analog JJ signal NN within IN the DT range NN of IN transmitted JJ speech NN , , typically RB from IN 300 CD to TO 3 CD , , 400 CD Hz NP . SENT contained VVN within IN a DT 0 CD 4000 CD z SYM channel NN . SENT Voice NN grade NN channel VVP A DT telecommunications NN circuit NN used VVN primarily RB for IN speech NN transmission NN typically RB supporting VVG frequency NN range NN of IN 300 CD to TO 3 CD , , 400 CD Hz NP . SENT also RB , , voice NN band NN . SENT W NP Top NP WATS NNS Wide NP Area NP Telephone NP Service NP . SENT An DT IXC NP service NN allowing VVG reduced JJ rates NNS for IN bulk JJ long JJ distance NN services NNS . SENT may MD be VB In IN WATS NNS , , or CC 800 CD number NN service NN , , where WRB calls NNS can MD be VB placed VVN to TO a DT location NN from IN anywhere RB at IN no DT cost NN to TO the DT calling VVG party NN , , or CC Out IN WATS NNS , , where WRB calls NNS are VBP placed VVN out RP from IN a DT central JJ location NN . SENT cost NN is VBZ based VVN on IN hourly JJ usage NN per IN WATS NNS circuit NN and CC on IN distance NN based VVN on IN zones NNS . SENT Waveguide NN A DT rectangular JJ metallic JJ pipe NN with IN the DT dimensions NNS of IN one CD half NN by IN one CD quarter NN wave NN length NN used VVN for IN directing VVG microwave NN electromagnetic NN radiation NN . SENT It PP has VHZ the DT advantage NN of IN low JJ signal NN loss NN per IN unit NN of IN distance NN . SENT Wavelength NN Distance NP between IN successive JJ peaks NNS of IN a DT sine NN wave NN . SENT Wavelength NN 1 CD frequency NN x SYM the DT speed NN of IN light NN . SENT Wavelength NN Division NN Multiplexing VVG WDM NP A DT technique NN for IN increasing VVG the DT fiber NN optic NN capacity NN by IN signaling VVG a DT more JJR than IN one CD frequency NN . SENT One CD fiber NN can MD be VB used VVN to TO send VV data NNS at IN multiple JJ frequencies NNS simultaneously RB . SENT This DT technique NN is VBZ similar JJ to TO frequency NN division NN multiplexing VVG but CC is VBZ used VVN in IN optical JJ transmissions NNS . SENT Wideband NP Generally RB , , a DT communications NNS channel VVP offering VVG a DT transmission NN bandwidth NN wider JJR than IN a DT voice NN grade NN channel NN . SENT Window NN A DT flow NN control NN mechanism NN in IN data NN communications NNS , , the DT size NN of IN which WDT is VBZ equal JJ to TO the DT number NN of IN frames NNS , , packets NNS , , or CC messages NNS that WDT can MD be VB sent VVN from IN a DT transmitter NN to TO a DT receiver NN before IN any DT reverse JJ acknowledgment NN is VBZ required VVN . SENT Wiring NN closet NN Termination NN point NN for IN customer NN premises NNS wiring NN , , offering VVG access NN to TO service NN personnel NNS . SENT generally RB serves VVZ a DT specific JJ area NN , , with IN multiple JJ wiring NN closets NNS that WDT are VBP cross NN connected VVN . SENT X NP Top NP X NP off IN X NP on IN Transmitter NN off IN transmitter NN on IN . SENT a DT commonly RB used VVN peripheral JJ device NN flow NN control NN protocol NN , , used VVN extensively RB for IN modem NN control NN by IN an DT attached VVN terminal NN or CC processor NN . SENT XC NP Cross NP connect VVP . SENT Z NP Top NP Zero NP transmission NN level NN point NN 0 CD TLP NN In IN telephony NN , , a DT reference NN point NN for IN measuring VVG the DT signal NN power NN gain NN and CC losses NNS of IN a DT circuit NN , , at IN which WDT a DT zero CD dBr NN 0 CD signal NN level NN is VBZ established VVN . SENT