Comtech EF Data CDM-IP 300L - Manual (Page 122)

CDM-IP 300L IP-Centric Satellite Modem Rev. 1
CD/CDMIP300L.IOM
96
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.
A remote controller or terminal initiates communications on the remote link. 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