Nortel Networks 1000 User Manual

Page 51

Operation

Eight of the 10 bits are for PCM data, one bit is the call signaling bit,
and the last bit is a data valid bit. The 8-bit PCM portion of a channel is
called a timeslot . The DS-30X loop is clocked at 2.56 Mbps (one-half
the 5.12 MHz clock frequency supplied by the controller card). The
timeslot repetition rate for a single channel is 8 kHz. The controller card
also supplies a locally generated 1 kHz frame sync signal for channel
synchronization.

Signaling data is transmitted to and from the line cards using the call
signaling bit within the 10-bit channel. When the line card detects
a condition that the switch needs to know about, it creates a 24-bit
signaling word. This word is shifted out on the signaling bit for the
associated channel one bit at a time during 24 successive DS-30X frames.
Conversely, when the switch sends signaling data to the line card, it is sent
as a 24-bit word divided among 24 successive DS-30X frames.

Figure 12
DS-30X loop data format

DS-30Y network loops extend between controller cards and superloop
network cards in the common equipment, and function in a manner similar
to DS-30X loops. See

Figure 13 "Network connections to IPE modules"

(page 52)

Essentially, a DS-30Y loop carries the PCM timeslot traffic of a DS-30X
loop. Four DS-30Y network loops form a superloop with a capacity of 128
channels (120 usable timeslots).

See Communication Server 1000M and Meridian 1 Large System Planning
and Engineering (NN43021-220) for more information on superloops.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311

02.06

Standard

27 August 2008