AT&T 3.0 Telephone User Manual


 
Trunk Errors
NOTE:
Maintenance-busy does not apply to DID trunks, since DID trunks cannot be
used to make outgoing calls.
While the trunk is in a maintenance-busy state, the software periodically runs
tests, attempting to seize the trunk:
If the seizure is unsuccessful, the trunk stays in a maintenance-busy
state.
If the seizure is successful, the trunk is placed back in service.
If a test is running when an incoming call is received on the trunk, the
test is dropped and the call is processed.
No more than 50 percent of trunks in a pool can be maintenance-busy at one
time. The only exceptions are as follows:
User-imposed maintenance-busy (for example, module replacement)
Module maintenance-busy (for example, a loss-of-service alarm in the
100D module)
No external release at the central office end of the line
Permanent Errors
A permanent error is entered in the error logs when more than 50 percent of
the trunks in a pool are maintenance-busy. When the maintenance-busy level
falls below 50 percent, the system automatically removes the permanent error.
NOTE:
Make sure that modules are not in a maintenance-busy state during a backup
procedure. Any module in a maintenance-busy state is recorded as such on
the backup disk.
Maintenance-Busy Causes
The causes of maintenance-busy vary according to the type of trunk and are
detailed in the following sections.
Central Office Problems 5-5