Nortel NT1R20, Description, Page: 28 / 316

Page 4 of 290 Description
553-3001-105 Standard 5.00 June 1999
Meridian 1 architecture
A Meridian 1 switch is a digital telephone system that provides both voice
and data transmission. The internal hardware is divided into the following
functional areas (see Figure 1).
Common equipment
Common equipment circuit cards provide processor control, software
execution, and memory functions to the system. Meridian 1 processor
functions are executed by the system software in the CPU module (sometimes
called a Core module). This module is normally located at the bottom of the
Meridian 1 column. The CPU manages the telephone switching functions by
responding to interrupt requests from the network and peripheral equipment.
It also performs the following housekeeping functions:
— controls call origination, call termination, and feature operation for
switched voice and data calls
— executes system administration and configuration functions
— coordinates system diagnostic activities
— controls system utility functions such as software loading, initialization,
data dumping, traffic logging, and system auditing
Network equipment
Network interface circuit cards perform data and control switching functions
between the processor and peripheral equipment cards.
Note: As shown in Figure 1, the network interface function is generally
considered a subset of the common equipment functions.
Some of the functions that network equipment performs include the
following:
— hardware initialization and self-test upon power-up
— establishes call connections between stations connected to remote IPE
line cards and stations local to the Meridian 1
— establishes call connections to trunks for long distance trunk calls over
public or private networks
— provides local and remote loopback testing and fault isolation functions