Comtech EF Data SDM-2020, Installation And Operation Manual

Page: 176 / 215

Rev. 3 B-1
B
Appendix B.
REMOTE CONTROL OPERATION
This appendix describes the remote control operation of the SDM-2020 demodulator.
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Firmware number: FW/7734-1
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Software version: 20.1.1
B.1 General
Remote controls and status information are transferred via an EIA-485 (optional EIA-232)
serial communications link.
Commands and data are transferred on the remote control communications link as
US ASCII-encoded character strings.
The remote communications link is operated in a half-duplex mode.
Communications on the remote link are initiated by a remote controller or terminal. The
demodulator never transmits data on the link, unless it is commanded to do so.
B.2 Message Structure
The ASCII character format used requires 11 bits/character:
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1 start bit
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1 parity bit (Not applicable to 8 information bit setup)
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2 stop bits
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7 information bits or 8 information bits with no parity bit