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B.5 packet structure, B.5.1 start of packet, B.5.2 target (base) address – Comtech EF Data PCB-4300 User Manual

Page 81

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PCB-4300 1:2 Phase Combiner

Revision

2

Appendix B

MN/PCB4300.IOM

B–3

B.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: <0412/MUT=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: >0412/MUT={CR}{LF}

B.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.

B.5.2 Target (Base) Address

Up to 9,999 devices can be uniquely addressed. In both EIA-232 and EIA-485 applications, the permissible range of values is 1 to 9999. It
is programmed into a Target unit using serial remote control.

IMPORTANT

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.