Comtech EF Data SDM-300A, Installation And Operation Manual

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SDM-300A Satellite Modem Remote Control Operation
Rev. 4 B–3
B.2.3 Command/Response
The command/response portion of the message contains a variable-length character
sequence which conveys command and response data.
If a satellite modem receives a message addressed to it which does not match the
established protocol or cannot be implemented, a negative acknowledgment message is sent
in response. This message is:
•
>
add/?ER1_parity error'cr''lf']
(Error message for received parity errors.)
•
>add/?ER2_invalid parameter'cr''lf']
(Error message for a recognized command which cannot be implemented or has parameters
which are out of range.)
•
>
add/?ER3_unrecognizable command'cr''lf']
(Error message for unrecognizable command or bad command syntax.)
•
>add/?ER4_modem in local mode'cr''lf']
(Modem in local error; send the REM command to go to remote mode.)
•
>add/?ER5_hard coded parameter'cr''lf']
(Error message indicating that the parameter is hardware dependent and may not be changed
remotely.)
Note: “add” is used to indicate a valid 1 to 3 character device address in the range
between 1 and 255.
Example: Command: <3/REM_
Response: >3/REM_
B.2.4 End Character
Each message is ended with a single character which signals the end of the message:
•
“cr”
Carriage return character for commands
•
“]”
End bracket for responses