Comtech EF Data CRS-400 - Manual (Page 77)

CRS-400 1:8 Redundancy Switch Revision 0
Remote Control MN/CRS400.IOM
61
All data is transmitted in framed packets. The controller is assumed to be a PC or ASCII
dumb terminal, that is in charge of the process of monitor and control. The controller is
the only device that is permitted to initiate, at will, the transmission of data. Targets are
only permitted to transmit when they have been specifically instructed to do so by the
controller.
All bytes within a packet are printable ASCII characters, less than ASCII code 127. In
this context, the Carriage Return and Line Feed characters are considered printable.
All messages from controller to target require a response (with one exception). This will
be either to return data that has been requested by the controller, or to acknowledge
reception of an instruction to change the configuration of the target. The exception to this
is when the controller uses Address 0 (universal address) in EIA-485 mode. In this case,
the target does not respond.
B.5 P
ACKET
S
TRUCTURE
Controller-to-target:
Start
of
Packet
Target
Address
Address
Delimiter
Instruction
Code
Code
Qualifier
Optional
Arguments
End of
Packet
Character < / = or ?
Carriage
Return
ASCII
Code
60 47 61 or 63 13
Number of
Characters
1 4 1 3 1 n 1
Example: <0000/RSH=30{CR}