DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-1703TDM-BUS (TDM Bus)
9
TDM-BUS (TDM Bus)
Each port network has a pair of TDM buss es, designated TDM Bus A and TDM
Bus B, each with 256 time slots. This division allows for d uplication of c ontrol
channels and ded icated tone time slots. The first five time slots on e ach bus are
reserved for the control channel, whic h is active on only one bus at a ti me in each
Port Network. The next 17 time slots are reserved for system tones such as dial
tone, busy tone and so on. As with the c ontrol channel, these time slots are active
on only one bus, A or B, at a time. The rest of the time slots on eac h bus are for
general system use such as c arrying call-associ ated voice data. The 17
dedicated tone time slots that are inactive can al so be used for call p rocessing
when all other available time slots are in use.
When the system initializes, the control channel is on TDM Bus A and the
dedicated tones on TDM Bus B in each Port Network. If a failure occ urs on one of
the two busses, the system will switch any c ontrol, tone and traffic c hannels to
the other bus. Service will still be p rovided, though at a red uced cap acity.
The set tdm PC command has the effec t of putting both the c ontrol channel and
tone time slots on a specified bus, A or B. P specifies the p ort network number,
and C specifies the TDM b us, A or B. Throughout this discussion, PC refers to a
specific TDM Bus. References to

port circuit packs

include all circ uit packs that
terminate on the TDM bus, including the Expansion Interface TN570, and the
following service circ uit port boards: Call Classifier (TN744), Integ rated
Announcement (TN750), Maintenance/Test (TN771), Speech Synthesizer
(TN725B), Tone Detector (TN748 or TN420). Other terms used are:
■Control Channel Bus: the TDM Bus carrying the ac tive control channel.
■Non-Control Channel Bus: the tdm bus with the inac tive control channel.
■Tone Bus: the TDM bus carrying the active tone time slots
■Non-Tone Bus: the TDM Bus with the inactive tone time slots
MO Name (in
Alarm Log) Alarm
Level Initial Command to Run1
1. P is the Port Network number. Use list cabinet to find the port network(s) contained in a
given cabinet.
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