Comtech EF Data SMS-7000 - Manual (Page 120)

Remote Control Operation SMS-7000 Modem Protection Switch
A–4 Rev. 3 Draft
A.2.1 Start Characters
A single character precedes all messages transmitted on the remote link. This character
flags the start of a message, as follows:
• “<” for commands
•
“>” for switch responses, or “>>” for modem responses through the
switch.A.2.2 Device Address
The device address is the address of the one switch or modem which is designated to
receive a transmitted command, or which is responding to a command.
Valid device addresses are 1 to 3 characters long, and in the range of 1 to 255. Address 0 is
reserved as a global address which simultaneously addresses all devices on a given
communications link. Devices do not acknowledge global commands.
Each switch which is connected to a common remote communications link must be
assigned its own unique address. Addresses are front panel software selectable, and must be
in the range between 1 to 255.
A.2.2 Command/Response
The command/response portion of the message contains a variable-length character
sequence which conveys command and response data.
If the switch 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/?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_switch not in remote mode'cr''lf']
(Switch not in remote error; use 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.)
•
>add/?ER6_busy'cr''lf']
(Error message indicating that the command sent cannot be carried out because local
processing is utilizing the modem control bus.)