Comtech EF Data CRS-200 - Manual (Page 66)

Remote Control CRS-200 Redundancy Switch
B–6 Rev. 1
The * code (target to controller) is only used as follows:
If the controller sends an instruction to set a parameter to a particular value, then, if the
value sent in the argument is valid, BUT the modem will not permit that particular
parameter to be changed at that time, the target will acknowledge the message by
replying (for example) with TFQ* (with no message arguments).
The ! code (target to controller) is only used as follows:
If the controller sends an instruction code that the target does not recognize, the target
will acknowledge the message by echoing the invalid instruction, followed by the !
character with. Example: XYZ!
B.5.5 Message Arguments
Arguments are not required for all messages. Arguments are ASCII codes for the
characters 0 to 9 (ASCII 48 to 57), A to Z (ASCII 65 to 90), period (ASCII 46) and
comma (ASCII 44).
B.5.6 End Of Packet
Controller to Target: This is the ‘Carriage Return’ character (ASCII code 13)
Target to Controller: This is the two-character sequence ‘Carriage Return’, ‘Line Feed’.
(ASCII code 13, and code 10).
Both indicate the valid termination of a packet.