Verilink NCC 2130 (880-503285-001) Product Manual User Manual
Page 51
Diagnostics
Verilink NCC 2130 User Manual
5-9
Figure 5-3
Sending Loop-up Code.
If the loop-up code reaches the far CSU and it is optioned to
respond to loop-up codes, then the far CSU enters a line loop
condition. Now the local CSU receives whatever it is sending.
NOTE: Whenever the Inband Up command is used to send a loop-up
code to a far end CSU, the Inband Down command must be
used later to send the loop-down code. Otherwise, the far end
CSU will be left in a looped condition.
Sending a Pattern
Begin transmitting a test pattern by using the qrss command.
Verify the pattern received matches the pattern transmitted by
using the show cntr command.
Figure 5-4
Sending and Receiving Pattern
If the QRSS pattern is received with no errors, the Test Error
Counter will not increment.
If the Test Error Counter does increment, one of the following
applies:
•
The far end CSU never went into a loopback and therefore the
test pattern being transmitted is not being received at all. This
would cause the Test Error Counter to increment at a rapid and
steady rate.
•
The far end CSU did go into a loopback, but the pattern
received at the local NCC 2130 does not match the pattern
transmitted. In this case the Test Error Counter might
increment in uneven amounts at virtually any rate.
Results
If the test passes, consider doing the same test with a different
pattern. Some patterns can fail on a T1 which passes other test
patterns. See
for details on the various patterns.
Loop-up code
Far CSU
Local NCC 2130
Test pattern sent
Far CSU
Test pattern received
(in Line Loop)
Local NCC 2130
Sends pattern
Checks pattern