Maintenance-Object Repair Procedures
555-233-143
8-1520 Issue 1 May 2002
3. If Stratum 3 is administered (display synchronization) and on-line
(status synchronization), check for DS1-BD or UDS1-BD slip errors for
the DS1(s) or UDS1(s) used as input to the Stratum-3 clock. Check the
LED indications on the Stratum-3 clock to determine which DS1 is
providing input to Stratum 3, and examine the cross-connect information
for that DS1.
4. Check for slips errors against EXP-INTF, SNI-BD, and TDM-CLK.
5. Check status synchronization for the current DS1 reference. If a DS1 or
UDS1 is on-line, check for slips on that DS1 or UDS1.
6. Check for LOS, Blue, Yellow, and Red alarms on the on-line reference
facility, and fix those problems first. See the DS1-BD and/or UDS1-BD for
the error log entries associated with the previously mentioned alarms.
Replace the circuit packs one at a time and wait at least one hour to
determine if the problem has gone away. This procedure is disruptive and
should be done after hours if possible.
An alternative to replacing the Tone-Clock circuit pack in systems where
the Tone-Clocks are duplicated, is to run the set tone-clock command to
interchange Tone-Clocks. If the problem goes away, the previously active
Tone-Clock should be replaced.
7. If a few facilities are experiencing slips or are unusable references, the
clock source for facilities with slips or that are unusable is not traceable to
the same ultimate source as the clock source for the on-line reference
facility.
Examine the overall timing network for the interconnected DS1 to
determine if the:
■ Clock can be traced back to a single source
■ Reference designations for each location in the distribution of timing
is supplied in accordance with the customer’s synchronization plan
Examine the capability of the external transmission equipment to pass or
provide timing.
Verify the integrity of the on-site hardware by using the technique, ‘‘Facility
Fault Sectionalization’’ on page 8-1522, which:
■ Loops the transmit signal to the receive signal
■ Verifies that the excessive slips or the unusable reference are no
longer observed
This is a time consuming process that disrupts service. You should
perform it after hours if the service being provided by the system is
acceptable as determined by checking with the customer.
8. Use status synchronization to determine the on-line reference. If a DS1
reference is not on-line and the local oscillator of a Tone-Clock board is
on-line, then the answer to this question is no.
To Next Page
Loading...
