ADTRAN Total Access 372 - NET Status LED Off Troubleshooting

Troubleshooting
61287722G1-5B 41
UPS Communication Signals
ThecommunicationsignalsoftheUPSareisolatedfromtheinternalcircuitryviaopen
collectoropto‐coupledtransistors.Theconnection
SIG RTN(SignalReturn)isacommon
returnpointforallcommunicationsignals.Inthetypicalapplication,theattachedequipment
digitalgroundconnectstoSignalReturn,andpull‐upresistorsturntheopencollectorsignals
intologiclevels.
ApinoutofthecommunicationsignalsisshowninTable13.
Table 13. UPS Communication Signal Descriptions
Signal Description
+12VDC Vo+(+Voltageoutput)
12VRTN Returnpathfor+12VDC
SIGNALRETURN Signalreturn
ONBATTERY Lowwhenoperatingfromutilityline
Openwhenoperatingfrombattery
REPLACEBATTERY Lowwhenbatteryischarged
Openwhenbatteryfailsself‐test
BATTERYMISSING Lowwhenbatteryispresent
Openwhenbatteryismissing
LOWBATTERY Lowwhenbatteryisnearfullcharg
ecapaci
ty
Openwhenoperatingfromabatterywithlessthan20%capacity