Comtech EF Data SDM-2020 - Manual (Page 203)

SDM-2020 Satellite Demodulator Revision 4
Remote Control Commands MN/SDM2020D.IOM
A–3
A.1.5 Command/Response
The command/response portion of the message contains a variable-length character
sequence, which conveys command and response data.
If a satellite demodulator 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.