Packet Structure; Start Of Packet; Address - Comtech EF Data LPOD PS-1 Installation And Operation Manual

LPOD C-/Ku-Band Outdoor Amplifier / Block Up Converter (BUC)
Remote Commands
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 broadcasts a
message (such as Set time/date) using Address 0, when the target is set to RS-485 mode.
3.2.4

Packet Structure

Controller-to-Target:
Start of Target
Packet

Address

<
ASCII code 60
(1 character) (4 characters)
Example: <0412/MUT=1{CR}
Target-to-Controller:
Start of Target
Packet Address
>
ASCII code 62
(1 character) (4 characters)
Example: >0412/MUT=1{CR}{LF}
3.2.4.1

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.
3.2.4.2 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
IM PORTANT its own address.
Address Instruction
De-limiter Code
/
ASCII code 47
(1 character) (3 characters)
Address Instruction
De-limiter Code
/
ASCII code 47
(1 character) (3 characters)
3–4
Code Optional
Qualifier Arguments
= or ?
ASCII codes
61 or 63
(1 character) (n characters)
Code Optional
Qualifier Arguments
=, ?, !, or *
ASCII codes
61,63,33 or 42
(From 0 to n
(1 character) characters)
Revision 0
MN-LPOD
End of
Packet
Carriage Return
ASCII code 13
(1 character)
End of
Packet
Carriage Return,
Line Feed
ASCII codes
13,10
(2 characters)