Nortel Networks Circuit Card 311 - Manual (Page 24)

24 Overview
IPE digital line cards receive the data from the digital phone terminal
as 512 kHz Time Compressed Multiplexed (TCM) data. The digital line
card converts that data to a format compatible with the DS-30X loop and
transmits it in the next available timeslot. When a word is received from
the DS-30X loop, the digital line card converts it to the TCM format and
transmits it to the digital phone terminal over the digital line facility.
A separate dedicated DS-30X network loop is extended between each IPE
line/trunk card and the controller cards within an IPE module. A DS-30X
network loop is composed of two synchronous serial data buses. One bus
transports in the Transmit (Tx) direction towards the line facility and the
other in the Receive (Rx) direction towards the CS 1000E, CS 1000M, and
Meridian 1.
Each bus has 32 channels for Pulse Code Modulated (PCM) voice data.
Each channel consists of a 10-bit word. See
Figure 3 "DS-30X loop data
format" (page 25) . 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 eight-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.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
.