Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
The basic objective of any troubleshooting procedure is to determine the type and location of a problem. Once
this is accomplished, taking one of the following actions will usually restore the IMUX 2000 M-DACS system:
1. For setup problems, re-configure the IMUX 2000 M-DACS multiplexer or multiplexers that are not set
up correctly.
2. For public network problems, work with your Local or Inter-exchange carrier to correct the situation.
For private network problems, consult the network manager.
3. For equipment problems, replace the bad module or modules with spares.
8.2.2 GENERAL TROUBLESHOOTING HINTS
Use the following hints as general guides when troubleshooting an IMUX 2000 M-DACS system:
1. At each location, verify that the POWER LED on the IMUX 2000 M-DACS Shelf is on. If the POWER
LED is off, then there is a power-related problem.
2. In general, alway
s check for setup errors before performing in-service or out-of-service tests. This is
especially true during the check-out of a new installed sy
stem.
Setup problems may not appear immediately. For example, if at installatio
n time both
multiplexers in a point-to-point system are incorrectly configured for AMI operation
(instead of B8ZS), errors may not occur until later when a data pattern with very low ones
density is transmitted.
3. If a trouble occurs on a single channel, always check to see if similar troubles exist on other channels. If
troubles exist on multiple channels at the same time, then the source of the channel troubles is probably
a T1 circuit failure, a CM4 failure or a DACS module failure rather than several simultaneous channel
module failures.
4. To isolate a "soft" trouble
such as a low bit error rate on a data channel, or occasional clicks or pops on
audio channel
s
, try in-servi
ce T1 circuit monitoring before performing out-of-service testing. This can
minimize overall circuit down-time. Use the procedure in paragraph 8.2.6.
5. To isolate a "hard" trouble, as for example when troubleshooting a system that is unavailable because of
a high error rate or loss of frame synchronization, use the loopback procedure below. If a T1 test set is
available, perform an out-of-service test using the procedure in paragraph 8.2.7. Once a system is in
hard failure, you incur no additional downtime by using these techniques.
6 If any of the ports on the M-DACS is receiving a bad signal (or is not properly configured). Using the
IMUX 2000 NMS, verify that the DACS module settings are correct. Under the DACS module General
Status screen, verify that the DACS module does not have any alert or alarm. Under the Port Status
screen, the Port diagnostics counters can be monitored for any T1 errors. If the T1 signal coming into
the port is confirmed to be faulty, the problem lies either at the remote end of the link, or in the link
itself (for port 5 & 6, the problem could be coming from the CM4s).
If the signal is determined to be valid but the DACS module is erroneously reporting faults, the output
of the port should be looped-back using a loopback connector (for port 5 & 6, a Line Loopback can be
performed at the CM4). If the port continues to report problems, the DACS module should be replaced.
If the errors clear with the loopback, the configuration of the local and remote ends should be checked
again (For port 5 & 6, the CM4s should be checked again).
M-DACS-T1 RFL Electronics Inc.
October 25, 2004 8-2 (973) 334-3100
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