RS485 bus protocol

Byte 1 : Message start = 0x7E
Byte 2 : Command is RPPduId
Byte 3 : Address 0x00 reserved for de busmaster
byte 4+ : Message
byte last - 1 : Checksum off preveiuis bytes
byte last : end of message = 0x7F



Commands
PDU_ID_0_RESERVED       = 0x00,
POLL_REQUEST            = 0x01,
STATUS_RESPONSE         = 0x02,
CREDENTIAL_NOTIFICATION = 0x03,
INDICATION_REQUEST      = 0x04,
SET_MIFARE_KEYS         = 0x05,
SET_PARAMETER           = 0x06,
GET_PARAMETER           = 0x07,
GET_PARAMETER_RESPONSE  = 0x08,
RESTART                 = 0x09,


PollRequest example
0x7E, 0x01, 0x00, 0x01, 0x6C, 0x07F  => reader 1
0x7E, 0x01, 0x00, 0x02, 0x65, 0x07F  => reader 2

Status response example
0x7E, 0x02, 0x01, 0x00, 0x01, 0x40, 0x07F  => from reader 1
0x7E, 0x02, 0x02, 0x00, 0x01, 0xFD, 0x07F  => from reader 2