950-770-100
March 14, 1997
Revision 01
PG-Plus PRL-770
PairGain Engineering-Plant Series
Page 13
8. Fault Isolation
8.1
The circuit board metal enclosure has a System Status window through which Status LEDs may be
viewed. The Status LEDs indicate different system states such as status of power, and subscriber line
activity including on-hook, off-hook, ringing, and subscriber drop test activity. The top portion of
the PRL-770 reference label provides a guide to what the Status LEDs indicate (Figure 11).
Figure 11. PRL-770 Status Window
If the PRL-771 fails to indicate power on (as evidenced by the Power LED being off), perform the
following diagnostic and repair operations:
1
Verify that the PRL-771 and its corresponding COLU are installed on the same pair.
2
Verify that the corresponding COLU is installed and turned up, and that the HDSL Periodical
Power Up option is enabled.
3
Verify that the signal loss on the pair is no more than 41 dB at 130 kHz.
4
Replace the PRL-771.
5
Replace the corresponding COLU.
6
Check for a short placed on the HDSL Tip and Ring conductors, and remove if necessary.
7
Check for HDSL cable fault, and replace if necessary.
Summary of Contents for PRL-770
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