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General, Message structure, 2 general – Comtech EF Data CIM-300L User Manual

Page 92: 3 message structure, General 66

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CiM-300L IP Enabled Satellite Modem

Rev. 1

Serial Remote Control

CD/CIM300L.IOM

66

5.2 G

ENERAL

Remote controls and status information are transferred via an EIA-485 or EIA-232 serial
communications link menu selection.
Commands and data are transferred on the remote control communications link as
US ASCII-encoded character strings.
The remote control port baud rates can be selected from 110 to 19200 kbit/s.
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
modem never transmits data on the link unless it is commanded to do so.
The modem must be placed in Remote Mode by entering the REM command prior to
performing a configuration change.

5.3 M

ESSAGE

S

TRUCTURE

The ASCII character format used requires 11 bits/character:

!

1 start bit

!

Information and Parity bits (select one)

!

7 information bits and 1 parity bit (Odd/Even)

!

8 information bits (None)

!

2 stop bits

Messages on the remote link fall into the categories of commands and responses.
Commands are messages which are transmitted to a satellite modem, while responses are
messages returned by a satellite modem in response to a command.
The general message structure is as follows:

!

Start Character

!

Device Address

!

Command/Response

!

End of Message Character