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I/O Interface cannot recover framing from signal from RCVR module.
1. Is DS3 AIS Detect alarm on?
Yes, check for upstream XMTR DS3 AIS Detect alarm.
No, go to 2.
2. Is DS3 AIS Ins alarm on?
Yes, check for upstream XMTR alarms. If any XMTR alarm is on,
troubleshoot upstream XMTR. No, go to 3.
3. Is radio hot-standby?
Yes
A. Are A and B alarmed?
Yes, troubleshoot XMTR. No, go to B.
B. Remove/replace RCVR module.
C. Remove/replace alarmed DS3 I/O Interface.
DS3 input data being written to elastic buf-
fer on DS3 I/O interface is a different rate
than data being read from elastic buffer.
1. Remove/re-seat off-line I/O interface.
2. Temporarily disrupt RCV signal to
off-line RCVR.
AIS (blue signal), inserted at MUX (ex-
ternal to the radio) has been detected
by DS3 I/O INTFC RCV circuits.
Troubleshoot external MUX equipment
(fault is not in radio).
If XMTR DS3 AIS Detect alarm is on,
troubleshoot external MUX equipment at XMT end.
If not, troubleshoot upstream XMTR.
DS3 Frame Loss
DS3 Buffer Spill
DS3 Degraded
DS3 AIS Detect
DS3 AIS Insert
Figure 5 - 5 Troubleshooting DS3 Radio RCV Alarms
Signal from RCVR module (input to DS3
I/O INTFC) has exceeded provisioned
BER threshold (typical fade condition).
Is DS3 Frame Alarm also on?
Yes, troubleshoot DS3 Frame Alarm .
No, and no-fade condition confirmed
LOS has been detected at RCV input of DS3 I/O INTFC
and AIS (blue signal) is being inserted. Check for LOS at
XMTR end of hop.
If not:
1. Check for upstream XMTR alarms. Any XMTR alarms?
Yes, troubleshoot XMTR
No, go to 2.
2. Replace RCVR module on alarmed side.
3. Replace alarmed DS3 I/O INTFC module.
1. Replace RCVR module.
2. Replace alarmed DS3 I/O
INTFC module.
MDR-1087
07/13/05
5-13
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Troubleshooting
