Lucent Technologies Release 7 TDM-CLK (TDM Bus Clock)

DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4 June 1999
Maintenance Object Repair Procedures
9-1720TDM-CLK (TDM Bus Clock)
9
TDM-CLK (TDM Bus Clock)
NOTE:
Replacing the tone/cl ock circuit p ack requires a spec ial procedure
described in the documentation for TONE-BD. That section also desc ribes
the LED displays for this board.
The Time Division Multiplex (TDM) Bus Clock resides on the Tone-Clock circuit
pack, providing clocking s ignals both for the TDM Bus and the LAN Bu s. The
Tone-Clock circuit pack is a c ritical component in the sy stem and is necessary to
ensure the operation of all port circ uit packs in the system. The TDM buses of the
PPN and any EPNs are synchronized together. The system timing reference c an
be derived internally f rom the Tone-Clock circuit pack in any PN, or from an
external (off-board) timing referenc e. Currently, the TDM Bus Clock supports
synchronizing the TDM Bus with interfac e rates from Digital Signal 1 (DS1)
facilities as primary or p rimary and second ary references, and from Stratum 3
Clock (STRAT-3) facilities. Only the TN780 tone-clock supports a Stratum 3 clock.
Moreover, the Tone-Clock circuit pack aid s in monitoring and selec ting
synchronization references. The Tone-Clock circuit pac k, after detecting tha t the
external source of timing is not valid , will automatically beg in its escalation
procedure, acc ording to the faciliti es administered. In the following table,
successive losses of sig nal cause escalation from left to rig ht.
NOTE:
Switching back to a DS1 source is handled by sync hronization
maintenance, once any p roblems with it have been correc ted and tested.
However, once synchronization has b een switched to the internal timing
source of the master Tone-Clock circuit pac k,
switch ing back to a St r atum 3
Clock must be initiated by a technician
after the external reference has
been repaired.
MO Name (in
Alarm Log) Alarm Level Initial Command to Run1
1. UU is the universal cabi net number (1 for PPN, 2 -44 for EPNs). C is the c arrier
designation (A, B, C, D, or E).
Full Name of MO
TDM-CLK MAJOR test tone-clock UUC short TDM Bus Clock
TDM-CLK MINOR test tone-clock UUC s hor t TDM Bus Clock
TDM-CLK WARNING release tone-cloc k UUC TDM Bus Clock