Instruction manual

025-9209 47
THEORY OF OPERATION
BASIC FUNCTIONAL DESCRIPTION
The Models 1708 and 1716 Remote Terminal Units are microprocessor-based systems with a
software intensive architecture that greatly enhances the versatility of the RTUs and allows
them to be quickly adapted to varied tasks.
The microprocessor controls all internal operations, radio audio path control, RS-232 serial
port and external input/output interface operations.
FUNCTIONAL BLOCK DIAGRAM
Microprocessor
Input
Protector/
Buffers
RS-232
AUX Inputs
Transmit Request
COR
RS-232 In
RS-232 Out
Digital
Outputs/Inputs
A
nalog
Inputs/Outputs
Outside
World
Outside
World
Output
Latch/
Buffer
PTT
A
uxiliary
Control
Outputs
MSK
Modem
Audio
Processing
& Gain
Discriminator
Summing
A
udio
A
mplifie
r
External Audio
A
udio Out
(For local programming only)
Figure 7. RTU Functional Block Diagram