Mitsubishi Electric MELSEC IQ-R series Reference Manual page 262

Mode No.
Specify the communication protocol setting after switching the C24 mode.
Mode No. Operation mode
01H MC Protocol (Format 1)
02H MC Protocol (Format 2)
03H MC Protocol (Format 3)
04H MC Protocol (Format 4)
05H MC Protocol (Format 5)
06H Nonprocedural protocol
07H Bidirectional protocol
09H Predefined protocol
FFH MELSOFT connection, GX Developer connection
■Data communication in ASCII code
Convert the numerical value to 2-digit ASCII code (hexadecimal), and send it from the upper digits.
■Data communication in binary code
Send a 1-byte numerical value from lower byte (L: bits 0 to 7).
Ex.
When mode No. is '1' (MC protocol (Format 1))
ASCII code
0 1
30 31
H H
13 SERIAL COMMUNICATION MODULE DEDICATED COMMANDS
260
13.4 Mode Switching Function
Binary code
01
H