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4.8 MTCP/MRTU
When modem work in MTCP/MRTU mode,can support converting data from
modbus RTU to modbus TCP. This working mode is based on PROT
mode(transparent transmission)
Modbus RTU frame format:
Slave ID:
1 bytes, used to identify modbus frame transmitted on the TCP/IP stack
Function Code:
1 bytes, coding range 1-255
Data:
N*1 bytes, length and content are determined by the type of Function code
Error Check:
2 bytes, CRC check, used to check whether the received data is correct.