How It Works - ACC RC-96 Owner's Manual

Chapter 9
How It Works
. The RC-96 Repeater Controller is centered around a microcom ­
puter with a software program contained in EPROM memory.
Program stored in EPROM means that the controller is ready to
go as soon as it's powered up. The microcomputer detects the
logic inputs to the system and the Touch-Tone decoder informa ­
tion and controls the logic outputs, audio switching and mixing,
speech synthesizer, and other circuits. More importantly, the
computer directs operation of the various features of the control­
ler, such as retpote programming, autopatch, remote base linking,
etc.
A block diagram of the RC-96 controller is shown on page 87.
The major functional blocks include the.microcomputer, audio
switching and mixing circuits, buffered I/O, speech synthesizer,
tone generator, Touch-Tone decoder, and telephone interface. In
addition, various protective circuits ensure reliable long tenn
operation with automatic error recovery.
The microcomputer consists of an 8085 microprocessor (U25)
with 80K bytes or more.ofEPROMprogrammemory (U29,
U34), 8K of E 2 PROM re-programmable non-volatile memory
(U31), 8K of RAM (U30), and various I/O circuits. Remotely
programmed information is stored in the E2PROM.
The CPU is automatically reset on powerup and will be reset
whenever the voltage to the CPU drops below its specification.
The 8085 multiplexed address/data bus is demultiplexed by the
74HC373 octal latch (U32), and its address space is decoded by
the PALlOL8 decoder (U33).
RC-96 REPEATER CONTROLLER OWNER'S MANUAL • 85