Specifications

Alarms & Diagnostics
MP2100M-LS-2 Modules - Installation and Operation Manual 3-7
If the local subscriber receives its own signal when the local loopback is
connected, the problem is at the remote end. To check, repeat the procedure on
the remote MEGAPLEX.
For modules having built-in modems (e.g. LS-2/M), use the following
procedure:
• Request the user to perform a local loopback test on the external modem
connected to its equipment. If the user equipment does not receive its own
signal, the problem is in the connections between the user equipment and
the external modem to which it is connected, or in the external modem
itself. After correcting the problem, continue troubleshooting as explained
below.
• Send a remote loop command from the external modem to activate the
externally-initiated local modem loopback on the LS-2/M channel. The user
equipment connected to the external modem must receive it own signal.
If the signal is not received, the problem is probably in the connections
between the external modem and the LS-2M channel, or in the external
modem. If after checking these items the problem in the local modem
loopback persists, replace the local LS-2/M module.
• Activate the local digital loopback on the LS-2/M channel. The user
equipment connected to the external modem must receive its own signal. If
the signal is not received, replace the local LS-2/M module.
• Activate the remote digital loopback on the remote module channel
connected to the local LS-2/M channel (this is not necessarily another
LS-2/M module). The user equipment connected to the local external
modem must receive its own signal.
If the signal is received, the problem is in the equipment located at the
remote location, or in the connections of the remote user equipment.
• If the signal is not received when the remote digital loopback is activated,
activate the local main link loop on the local MEGAPLEX unit.
If the user equipment connected to the local external modem does not
receive its own signal when the main link loop is connected, the problem is
in the local MEGAPLEX unit.
• If the signal is received when the main link local loopback is activated,
activate the remote main link loop.
If the user equipment connected to the local external modem does not
receive its own signal, the problem is either in the time slot allocation, or in
the remote MEGAPLEX unit.