User guide

6-4 Solo E1 DSU User Guide—June 1998
6
If the Solo E1 DSU still does not loopup, use your E1 test set to inject a
fractional loopback signal into the payload you wish to loopup.
The NET LED does not Illuminate
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 DA-15
female connector on the back of the Solo E1 DSU.
Remove the E1 line from the back of the Solo E1 DSU 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, 3Ñtip, 11Ñring). 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.
If the NET LED does not light, place the E1 loopback plug on the network
connector on the back of the Solo E1 DSU. If it then changes color,
troubleshoot your test setup. If no test plug is available, loopback pins 1
and 3, and pins 9 and 11. The NET LED should light green.
The NET LED is Constantly Red
Make sure the E1 line framing format matches the Solo E1 DSU framing
format.
Check the Solo E1 DSU for excessive errors.
In CRC4 mode, check for CRC and CVs; in unstructured mode, check for
CVs only. If excessive errors appear, place your E1 test set or your loopback
plug on the DA-15 female connector on the back of the Solo E1 DSU to see
if the errors stop.
If they do, contact your service provider for assistance.
The NET LED Remains a Constant Yellow
Check to see if the Solo E1 DSU is receiving a RAI alarm or an UA1 alarm.
Make sure the remote/far end Solo E1 DSU is receiving a proper E1 signal.
If it is not, it will be generating an RAI alarm towards your equipment.
If the Solo E1 DSU is still receiving an RAI alarm, place the E1 test set or
the E1 loopback plug on the DA-15 female connector on the back of the
Solo E1 DSU. If the RAI alarm stops, contact your service provider for
assistance.
If, after all above steps have been satisÞed, your Solo E1 DSU still shows a
yellow NET LED, call Digital Link Technical Support for assistance.