Microwave Data Systems MDS 4310, Installation, Operation & Field Maintenance

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MDS 05-2415A01, Rev. A C-1
APPENDIX C
9600 BPS FSK MODEM
Optional System Equipment
Assembly P/N: 03-1833A01
INTRODUCTION
The 03-1833A01 modulator/demodulator (modem) was designed specifically for use with the
MDS 4300 Series Transceivers, allowing it to be mounted within the transceiver housing.
This modem is capable of synchronous or asynchronous operation at 9600 bits-per-second
(bps). With this option mounted within the transceiver enclosure, the MDS 4310 Transceiver
can still be programmed via the RS-232 connector, without the need to remove the housing
cover.
SPECIFICATIONS
Current Drain: 30 mA from the primary power source
Data Rate: 9600 bps Synchronous or Asynchronous
INSTALLATION
The 03-1833A01 modem installs within the transceiver housing on the transceiver main
board at jacks J6 and J8. The modem contains an eight section set-up and test switch, S1,
which is used to configure the modem for operation in a number of installation arrangements.
Table C-1 describes the function and recommended setting of each of these eight switch
sections.
ALIGNMENT
There is no alignment of the MDS 9600 bps modem required. However, should the modem
be added to a radio that previously did not have a modem, or a defective modem is replaced
with a new one, it is advisable to check the radio’s deviation and frequency setting before
returning the radio to service. Details on setting the deviation and frequency are covered in
Chapter 4—Field Tests & Adjustments.
THEORY OF OPERATION
Transmit Data
CTS is factory set to go high 10 ms after transmit data is received from the external system
via Pin 2 on the
INTERFACE
connector. The time period is controlled by micro-controller U16
on the transceiver board, but the period is user programmable (2 to 255 ms). This data goes
through U31 on the transceiver main board for the RS-232 configuration or through bypass
jumpers in place of U31 in the TTL configuration. The transmit data is fed into the data
processor U6.