Instruction manual

FUNCTIONAL DESCRIPTION
Common Control
The Common Control circuitry consists of a single ZTN142 CPU/MEM (Call Processing
Unit/Memory) circuit pack (CP).
CPU/MEM CP
The CPU/MEM runs the system feature code for the system and provides for the storage of
software associated with system operation. This CP is powered from the backplane by +5 and –5
volts. It also draws -48 volts from the backplane to drive the Emergency Transfer Unit. The CP,
shown in Figure 3-2, includes the following circuits:
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Microprocessor
A 68010 16-bit microprocessor that executes call processing and data processing features.
This includes all maintenance, administration, testing, and reporting software.
Memory Management
Memory management separates the on-board Random Access Memory (RAM) into 1024
memory pages of 256 bytes each. Each page is read and write protected and generates
bus errors when violated.
On-Board Memory
On-board memory includes 1 Mbyte of Read Only Memory (ROM) containing the powerup
tests, the switch operating system, and the system operation software. In addition, there are
192k bytes of protected RAM containing writeable data storage for call processing. The
RAM is backed up by an on-board trickle-charge battery that maintains memory contents
for up to two months. Of the 192k RAM, 32k is dedicated to translation data. The remainder
is dedicated to call status data and the operating system message queues.
EIA Channels
Four asynchronous RS-232 EIA ports (1-4) are included to permit communication with an
administration terminal, a Station Message Detail Recording (SMDR) device, and a digital
tape unit. (The fourth port is reserved for future use.) Each port can support 300, 1200,
4800, or 9600 baud rates.
Network Controller
The network controller transmits control channel messages between the Call Processor and
the port circuits over the TDM bus. The controller also monitors system clocks. The
controller includes an 8-bit microprocessor that acts as a throttle passing messages
between the Call Processor and the port board microprocessors.
3-2
November 1995