Comtech EF Data CDM-IP 300L - Manual (Page 123)

CDM-IP 300L IP-Centric Satellite Modem Rev. 1
CD/CDMIP300L.IOM
97
5.3.1 S
TART
C
HARACTER
A single character precedes all messages transmitted on the remote link. This character
flags the start of a message. This character is:
“<” for commands
“>” for responses
5.3.2 D
EVICE
A
DDRESS
The device address is the address of the one satellite 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.
Note: 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 satellite modem, which is connected to a common remote communications link,
must be assigned its own unique address. Addresses are software selectable at the
modem, and must be in the range of 1 to 255.
5.3.3 C
OMMAND
/R
ESPONSE
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.)