Black Box LRU4240 - Manual (Page 103)

Dual Trunk E1 Router
Dual Trunk E1 Router User’s Guide TECHNICAL: 0118 96 56 000 91
The NET LED does not
illuminate.
• No incoming signal.
• Bad LED.
• Run a lamp test from Menu-9,
Diagnostics to make sure the LEDs
are working.
• Make sure the E1 line from your
service provider is connected to the
RJ-48C female connector on the
back of the LRU4240 NTU.
• Remove the E1 line from the back
of the LRU4240 and place the E1
test set in its place. Connect the
transmit of the E1 test set to the
receive of the network plug (pins 3
and 11, 3—tip, 11—ring). If the
NET LED changes to any color,
i.e., green or red, contact your
service provider for assistance with
cutting over the E1 line.
• Place the E1 loopback plug on the
network connector on the back of
the LRU4240. If it then changes
color, troubleshoot your test setup.
• If the NET LED never lights, call
Black Box Technical Support for
assistance.
The NET LED is constantly red. • Constant out-of-sync or out-of-
frame on E1.
• Misframe/FE.
• Carrier has problem.
• Configuration doesn’t match
framing.
• Make sure the E1 line framing
format matches the LRU4240’s
framing format.
• Check the LRU4240 for excessive
errors.
• In CRC4-Enabled mode, check for
CRC and CV; in CRC4-Disabled
mode, check for CVs only. If
excessive errors appear, place your
E1 test set or your loopback plug
on the RJ-48C or BNC socket on the
back of the system to see if the
errors stop.
• If they do, contact your service
provider for assistance.
• If the errors do not stop, call Black
Box Technical Support for
assistance.
Table 11-2 Network Problems (2 of 4)
Symptom Probable Cause Solution