Table of Contents
1General
2Characteristicsofinterfaces
2.1CharacteristicsofinterfaceC[2]
2.1.1Exchangeimpedance
2.1.2Impedanceunbalanceaboutearth
2.1.3Relativelevels
2.2CharacteristicsofinterfaceZ
2.2.1Exchangeimpedance
2.2.2Impedanceunbalanceaboutearth
2.2.3Relativelevels
3Characteristicsofhalf-connections
3.1Characteristicscommontoall2-wireanalogueinterfaces
3.1.1Transmissionloss
3.1.2Groupdelay
3.1.3Singlefrequencynoise
3.1.4Crosstalk
3.1.5Totaldistortionincludingquantizingdistortion
3.1.6Discriminationagainstout-of-bandsignalsappliedtothe
inputinterface
3.1.7Spuriousout-of-bandsignalsreceivedattheoutput
interface
3.1.8Echoandstability
3.2CharacteristicsofinterfaceC[2]
3.2.1Nominalvalueoftransmissionloss
3.2.2Noise
3.2.3Valuesoftotaldistortion
3.3CharacteristicsofinterfaceZ
3.3.1Nominalvalueoftransmissionloss
3.3.2Noise
3.3.3Valuesoftotaldistortion
AppendixI-Impedancestrategyin2-wirenetworks
I.1Introduction
I.2Generalequationsforunloadedcables
I.3Generalimpedanceconsiderationsofahybrid
I.3.1CableinputimpedanceZ[2]andthehybrid
inputimpedanceZ[T]
I.3.2BalanceimpedanceZ[B]
I.4Echoconsiderations
I.4.1TalkerecholoudnessratingTELR
I.4.2SidetonemaskingratingSTMRandlistener
sidetoneratingLSTR
I.5Applications
I.6Analysisofloopimpedancevariationbymeansof
aspecialimpedancediagram
I.7Conclusions
I.8ExamplesofimpedancesZ[2]andcompromisenominal
impedancesZ[T]andZ[B]
I.8.1CableinputimpedanceZ[2]andhybridinput
impedanceZ[T]
I.8.2BalanceimpedanceZ[B]
I.8.3Applicationofthespecialimpedancediagram
I.8.4Echoconsiderations Abstract
Gives characteristics for 2-wire analogue interfaces, input and output connections with 2-wire analogue interfaces and half-connections with 2-wire analogue interfaces as specified in Rec. Q.551. Valid for equipment that may terminate an international long-distance connection via 4-wire circuits interconnected by 4-wire exchange. Also covers, in a separate category, characteristics for interfaces which cannot terminate an international connection and are therefore entirely national in application.
