Comtech EF Data CRS-200 - Manual (Page 63)

CRS-200 Redundancy Switch
Rev. 1 B–3
reception of an instruction to change the configuration of the target. The exception to this
is when the controller broadcasts a message (such as Set time/date) using Address 0,
when the target is set to EIA-485 mode.
B.5 Packet Structure
Controller-to-target:
Start of
Packet
Target
Address
Address De-
limiter
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
code
61 or 63
(1 character)
(n characters)
Carriage Return
ASCII code 13
(1 character)
Example: <0000/RSH=30{CR}
Target-to-controller:
Start of
Packet
Target
Address
Address De-
limiter
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 code
61,63, 33 or
42
(1 character)
(From 0 to n
characters)
Carriage Return
Line Feed
ASCII code 3,10
(2 character)
Example: >0000/BBU=107{CR}{LF}
Each of the components of the packet is now explained.
B.5.1 Start Of Packet
Controller to Target: This is the character ‘<’ (ASCII code 61)
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.