Comtech EF Data CDM-600/600L - Manual (Page 195)

CDM-600/600L Open Network Satellite Modem Revision 3
Appendix D MN/CDM600L.IOM
D–3
D.5 Packet Structure
Controller-to-Target
Start of
Packet
Target
Address
Address
Delimiter
Instruction
Code
Code
Qualifier
Optional
Arguments
End of Packet
<
ASCII code 60
(1 character) (4 characters)
/
ASCII code 47
(1 character) (3 characters)
= or ?
ASCII codes
61 or 63
(1 character) (n characters)
Carriage Return
ASCII code 13
(1 character)
Example: <0135/TFT=1{CR}
Target-to-Controller
Start of
Packet
Target
Address
Address
Delimiter
Instruction
Code
Code
Qualifier
Optional
Arguments
End of Packet
>
ASCII code 62
(1 character) (4 characters)
/
ASCII code 47
(1 character) (3 characters)
=, ?, !, or *
ASCII codes
61,63,33 or 42
(1 character)
(From 0 to n
characters)
Carriage Return,
Line Feed
ASCII codes
13,10
(2 characters)
Example: >0654/RSW=32{CR}{LF}
D.5.1 Start of Packet
Controller-to-Target: This is the character '<' (ASCII code 60).
Target-to-Controller: This is the character '>' (ASCII code 62).
Because this is used to provide a reliable indication of the start of packet, these two characters
may not appear anywhere else within the body of the message.
D.5.2 Target Address
Up to 9,999 devices can be uniquely addressed. In RS-232 applications this value is set to 0. In
RS-485 applications, the permissible range of values is 1 to 9999. It is programmed into a Target
unit using the front panel keypad.
The Controller sends a packet with the address of a Target – the destination of
the packet. When the Target responds, the address used is the same address,
to indicate to the Controller the source of the packet. The Controller does not
have its own address.
D.5.3 Address Delimiter
This is the character ‘/’ (forward slash) (ASCII code 47).
IMPORTANT