Verilink NCC 2130 (880-503285-001) Product Manual User Manual
Page 55
Diagnostics
Verilink NCC 2130 User Manual
5-13
A T1 loopback plug can be made by taking a male RJ-45 connector
and placing two short jumper wires where a cable would normally
go. One jumper is placed from pin one to pin five, the other jumper
connects pin two to pin four. See
for
a drawing of a T1
loopback plug.
NOTE: When using a T1 loopback plug it might be necessary to
temporarily change the timing selection in the IDCSU. If the
IDCSU is set to recover network clock, it will be trying to
recover a clock it is trying to recover. The clock frequency
will drift. For this test, set the IDCSU clock source to Internal.
Remember to change it back after the test.
Figure 5-5
T1 Loopback Plug
RJ -45
8
Cable Side
Connector
2
4
5
1
RJ-45 plug held with plastic latching tab unseen at bottom