Protocol Structure - AEG ARE H9 HF User Manual

7.2 Protocol structure

All the commands have the following structure:
STX, command in ASCII, CRC in ASCII, ETX
The following answers are possible:
A Record with the structure given above,
ACK
BEL
NAK
Except STX and ETX, the total content of the commands are composed in
ASCII characters.
This procedure has been chosen explicitly, as a large number of host Operating
Systems react with their own functions, when they see characters outside of 0x20
to 0x7F.
The CRC is applied only on the characters of the „command", STX and ETX are
not
The 4 nibbles of the CRC are transmitted in form of 4 ASCII characters. By
doing so, the CRC is in conformance with the ASCII standard as well.
Control Control Hex Hex
Control Control Hex Hex
characters characters characters characters code code code code
STX 0x02
ETX 0x03
BEL 0x07
CR 0x0D
ACK 0x06
NAK 0x15
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Designation Designation
Designation Designation
Start Of Text
End Of Text
buzzer (bell)
Carriage Return
Acknowledge
Negative Acknowledge
included.
Function Function
Function Function
Begin of a Records
End of a Records
Signaling a specific condition, e.g..
if the interrogated memory site is
not occupied.
End of string
The command has been executed
successfully
The command was not recognized
and consequently has not been
executed (syntax error)