Instruction manual

HARDWARE DESCRIPTION
Required Circuit Packs
The following CPs are provided with all Release 3 systems and must be mounted in Cabinet 1:
● ZTN142 CPU/MEM (Call Processing Unit/Memory)
The ZTN142 (one per system) provides a central processing unit, Random-Access Memory
(RAM) (memory) for call and feature processing, interrupt controller, programmable timers,
real time clock, status display, processor bus interface, and four interface ports. It also
provides Read-Only Memory (ROM) for translations and a 1200-baud answer-only modem
for Remote Initialization and Maintenance Service (RIMS) access. The five interface ports
provide the following interfaces:
— Port 1 - System Administration Terminal (SAT)
— Port 2 - Station Message Detail Recording (SMDR) equipment
— Port 3 - Digital Tape Unit
— Port 4 - Reserved
— Port 5 - RIMS
The CPU/MEM also provides -48 VDC control on ports 7 and 8 for Emergency Transfer
Units.
The CPU/MEM CP must be mounted in slot 1 of Cabinet 1.
● ZTN131 Service Circuit
The ZTN131 (one per system) provides four touch-tone receivers, generates all system
tones, and supplies the system clocks. The ZTN131 can support up to 75 voice terminal
stations.
The ZTN131 synchronizes the System 25 to a master DS1 data stream, monitoring the
reference clock, and maintaining a stratum 4 clock for synchronizing transmission on all
DS1 ports.
The Service Circuit CP must be mounted in slot 2 of Cabinet 1.
4-8
November 1995