Gnlb Loopback Test Procedures - PairGain HiGain HLU-319 Manual

150-319-142-01
jacks and another between the two SPAN jacks splits the XMT and RCV and
creates metallic loopbacks towards both the DSX-1 and the HLU-319
List 4B. If separate plugs are inserted into both SPAN jacks with their other
end disconnected, the BRG jacks can be used to send and receive test patterns
towards the DSX-1.

GNLB Loopback Test Procedures

To perform the GNLB loopback test procedure:
1 Have the CO tester send into the HLU-319 List 8B a (3-in-7) in-band
loop up code for five seconds. Verify, if possible, that an NREM
loopback is in effect. (Loopback states are indicated by the green LOOP
LED on the front panel display and on the Span Status screen.)
2 Have the CO tester transmit a T1 test signal into the HLU-319 List 4B
and verify that the returned (looped) signal is error-free.
3 If step 2 fails, have the CO tester transmit a (3-in-5) in-band loopdown
code.
4 Have the CO tester send into the HLU-319 List 4B a (4-in-7) in-band
loop up for five seconds. Verify that an NLOC HLU-319 List 4B
loopback is in effect. (Loopback states are indicated by the green LOOP
LED on the front panel display and on the Span Status screen.)
5 Repeat step 2. If the test passes, the problem is in the downstream
direction. If it fails, the problem is in the upstream (CO) direction.
HLU-319 List 4B
December 22, 1997
PairGain Engineering - Plant Series
Revision 01
33