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Telos Zephyr Xstream Two-Way Radio User Manual

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USER’S MANUAL

Appendix 10 – Glossary 354

ISDN30AtermusedinEuropeforISDNPRI.AlsocalledS2MSeePRI.

ISG–IncomingServiceGroupingAHuntGroup.SeeHuntGroup

IXC‐IntereXchangeCarrierSeeIEC

KbpsKiloBitsPerSecond.Measureofdigitalchannelcapacity.

KeyTelephoneSystemAsystemthatallowsmultipletelephonestosharemul

tiplepre‐

determinedtelephonelines.Thesystemprovidesindicatorstoallowtheuser’stounderstand

thestatusofeachlineavailableonagivenphone.InitsmostbasicformitisUSER’SMANUALup

totheusertoprovidetheintelligencetoselectanunusedline,oransweraringingli

ne,for

example.TheTelos10,DirectInterfaceModule,One‐x‐Six,TWOx12andSeries2101canbe

classifiedasKeyTelephoneSystems.SeealsoPBX.

LATA‐LocalAccessandTransportAreaTheareawithinwhichcallsareroutedbyyourLocal

ExchangeCarrier(LEC).UnderthedivestitureoftheBellSyste

mcallsgoingoutsideofthisarea

mustbehandledbyanInterexchangecarrier(IEC).Withthelatestroundofde‐regulationthe

usualIECcompaniesarebeingallowedtocompeteintheIntraLATAlongdistancemarketand

LECsarebeginningtobepermittedtohandleInterLATAcalls.

LDN‐ListedDirect

oryNumberWhenanumberofTelcochannelssharethesamehuntgroup,it

iscustomarytogiveoutonlyonephonenumberforthegroup,althoughgenerallyeachchannel

willhaveitsownnumber.Thenumbergivenoutisthe“ListedDirectoryNumber”sincethatis

thenumberthatwouldbelistedintheT

elephoneDirectoryandgiventocustomers.Sometimes

calledaPilotNumber.SeealsoDNandHuntGroup.

LE‐LocalExchange.EuropeantermforCentralOffice.SeeCO.

LEC‐LocalExchangeCarrierYourlocaltelephoneserviceproviderwhichiseitheranRBOCoran

Independent.Inotherwor

ds,atraditionalphonecompany.IncontrasttoCLECorIEC.

LineAnelectricalconnectionbetweenatelephoneserviceprovider’sswitch(LECorCLEC)anda

telephoneterminalorKeysystem.Anelectricalconnectionbetweenatelephoneservice

provider’sswitchandanotherswitchistechnicallycalledatrunk.Notethatso

metypeof

physicallinesoffermorethanonechannel.I.E.aBRIcircuithas2channels,calledBchannels.

Thistermisaconfusingone,sowetrytoavoidusingit.SeeChannel.SeealsoStationLine.

LinecardThecircuitintheTelcoswitchtowhichyourlineiscon

nected.OnanISDNcircuitthe

linecardperformsaroleanalogoustotheNT1inadaptingtoandequalizingthecircuitto

establishOSILayer1.

LineCoding,T1TheclocksignalforT1isderivedatthefarendfromthedatabitsthemselves.

Therefore,T1lineshavecertainrestrictionsastoth

edataallowed.Nomorethan15zerosshall

besentinarow;andaveragedensityof12.5%onesmustbemaintained.TheCSUisresponsible

toensurethattheserequirementsaremet.Thelineencodingmethod,AMIorB8ZSdetermines

exactlyhowtheserequirementsaremetwhilestil

lallowingrecoveryoftheoriginaldataatthe

farend.YourTelcowilldeterminethemethodusedonaspecificcircuit.B8ZSispreferred.E1

circuitshavesimilarrestrictions.HDB3ispreferredforE1circuits.

ListedDirectoryNumberSeeLDN

LineEncoding,T1SeeLineCoding,T1.

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