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DEFINITY Enterprise Communications Server Release 5
Maintenance and Test for R5vs/si
555-230-123
Issue 1
April 1997
Maintenance Object Repair Procedures
Page 10-1389TDM-BUS (TDM Bus)
10
TDM-BUS (TDM Bus)
The TDM Bus consists of a duplicated TDM Bus on each port network (PPN and
EPN): TDM Bus A and TDM Bus B. Each TDM Bus consists of 256 time slots. The
first five time slots on each bus are called the Control Channel. The Control
Channel is active on only one bus at a time in each Port Network. The next 17
time slots are reserved for dedicated tones (that is, dial tone). These time slots
are called the dedicated tone time slots and only one bus at a time carries the
dedicated tones. The rest of the time slots on each bus are for general system
use (that is, phone call).
On system initialization, the Control Channel is on TDM Bus A and the dedicated
tones on TDM Bus B in each Port Network.
Systems with High or Critical Reliability have the ability to set the Control Channel
and Tone Bus to a specific TDM Bus via the set tdm PC command, where P
stands for the Port Network Number and C stands for the TDM Bus A or B (A for
TDM Bus A or B for TDM Bus B). Throughout this document, PC is used to refer
to a TDM Bus.
Terminology:
■ Control Channel Bus - The TDM Bus control channel is on.
■ Non-Control Channel Bus - The TDM Bus control channel is NOT on.
■ Tone Bus - The TDM Bus dedicated tone time slots are on.
■ Non-Tone Bus - The TDM Bus dedicated tone time slots are NOT on.
TDM Bus Fault Detection and Isolation
Procedure
TDM Bus faults are most likely caused by a defective circuit pack connected to
the backplane or bent pins on the backplane. It is possible that a circuit pack
can cause a TDM Bus fault but still exhibit trouble-free operation. For example,
the insertion of an MBUS (Memory Bus) only circuit pack can bend the TDM Bus
pins on the backplane and short two leads together. The four circuit packs that
may cause this problem are the TN770 Memory circuit pack, the TN777 80286
Processor circuit pack, the TN772 Duplication Interface circuit pack, and the
TN777 Network Control circuit pack. The latter exists only on High and Critical
Reliability systems. Since the TDM Bus is a shared resource, automatic
MO Name (in
Alarm Log) Alarm Level
Initial Command
to Run Full Name of MO
TDM-BUS MAJOR test tdm P TDM Bus
TDM-BUS MINOR test tdm P TDM Bus
TDM-BUS WARNING test tdm P TDM Bus