Comtech EF Data HPCST-5000 - Manual (Page 182)

Remote Control Operation High Power C-Band Satellite Terminal
B–2 Rev. 0
B.2 Message Structure
The ASCII character format used requires 11 bits/character:
! 1 start bit
! 7 information bits
! 1 parity bit
! 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 the RFT-500 in response to a command.
The general message structure is as follows:
! Start Character
! Device Address
! Command/Response
! End of Message Character
B.2.1 Start Character
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
B.2.2 Device Address
The device address is the address of the RFT-500 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 RFT-500 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.
Note: Global address '*' is reserved for EXTERNAL KEYPAD commands.