AT&T MERLIN LEGEND Installation & Maintenance Manual page 520

Maintenance and Troubleshooting
Manual Correction of Line/Trunk Problems
If the system cannot seize a line/trunk even after repeated
attempts, you may have to replace the module. To identify the
line/trunk problem, first check for a dial tone at the CU. If you do
not hear a dial tone, check the error logs and make a line/trunk
test call.
It is sometimes difficult for the customer to detect line/trunk
troubles. If a line/trunk is down, an error is recorded in the error
log and the line/trunk is taken out of service. If an incoming-only
line/trunk is down, however, the only sign of trouble is customer
complaints that incoming calls are not being received.
Check the error log for messages about trunk type (such as DID,
tie, and T1). Also check the wiring and the system parameters
(for example, touch-tone/rotary, toll restriction, and disconnect
time interval).
Outgoing Line/Trunk Problems
Symptom:
Outgoing lines/trunks cannot be seized.
Procedure:
1. At the network interface, check for a dial tone from the CO. If
a dial tone is not present, notify the customer.
Note: For GS lines/trunks, apply ground to the ring lead to
get a dial tone.
2. Pickup the handset at a test station to get a system dial tone.
3. For a Hybrid/PBX system, dial ∗03.
Note: Dialing ∗03 on a single-line telephone works only if the
line/trunk accepts touch-tone dialing. After you dial ∗03 on a
single-line telephone, you may have to wait for a "click" before
dialing the line/trunk number.
5-42 Maintenance