Maintenance-Object Repair Procedures
555-233-143
8-574
Issue 1 May 2002
Loop Start Operation
Idle State: Tip = ground, Ring = CO Battery
Outgoing Call
1. PBX Off-Hook (Seize Message): Closes the Tip-Ring Loop CO Response:
DC loop c Dial tone
2. PBX On-Hook (Drop Message): Open Tip-Ring loop, no loop current CO
Response: CO goes to idle state (see Note)
Incoming Call
1. CO Applies Ringing Voltage PBX Response: Detect ringing current
2. PBX Off-Hook (Answer Message): Close loop CO Response: Trip ringing,
provide loop current
3. PBX On-Hook (Drop Message): Open Tip-Ring loop, no loop current CO
Response: CO goes to idle state (see Note)
Direct Inward Dialing (DID)
1. CO Applies Ringing Voltage
PBX Response: Detect ringing current and close loop
CO Response: Send DTMF digits
PBX Response: Acknowledge of Number dialed and open loop
2. PBX Off-Hook (Answer Message): Close loop CO Response: Trip ringing,
provide loop current
3. PBX On-Hook (Drop Message): Open Tip-Ring loop, no loop current CO
Response: CO goes to idle state (see Note)
NOTE:
CO does not normally provide an On-Hook (Disconnect) signal.
Summary of Contents for S8700 Series
Page 50: ...Maintenance Architecture 555 233 143 1 26 Issue 1 May 2002 ...
Page 74: ...Initialization and Recovery 555 233 143 3 12 Issue 1 May 2002 ...
Page 186: ...Alarms Errors and Troubleshooting 555 233 143 4 112 Issue 1 May 2002 ...
Page 232: ...Additional Maintenance Procedures 555 233 143 5 46 Issue 1 May 2002 ...
Page 635: ...status psa Issue 1 May 2002 7 379 555 233 143 status psa See status tti on page 7 406 ...
Page 722: ...Maintenance Commands 555 233 143 7 466 Issue 1 May 2002 ...