Sagem MorphoAccess 200E, Руководство по установке

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Communication protocol
The communication protocol available allows the terminal to
send commands to a host through the communication
COM1/RS485.
All the commands will be formatted with an "Identifier Length
Value" structure as described below:
Identifier Length Value
Identifier called I This is the identifier of the command.
Length called L This is the length of the Value field in bytes.
Value called V The parameters or data.
The commands will be encapsulated in a packet structure
described on the next figure.
STX ID RC ILV CRC DLE ETX
CRC : Compliance CRC16 V41
Fields name Definition Value
<STX> Start Text 0x02
<ID> Packet Identifier 0xE1
<RC> Request Counter Unused byte
<ILV> Identifier Length
Data (DLE data
bytes arestuffed)
I:
0x00 for ASCII
0x01 for Hexa
0x02 for BCD
L: 2 bytes
V: Value of identifier
<CRC> Transmission error
control
Depends on the
frame
<DLE> 0x1B
<ETX> End Text 0x03
Communication protocol