Modbus TCP terminal. Supported Modbus functions: 01 (0x01) Read Coils. 02 (0x02) Read Discrete Inputs. 03 (0x03) Read Holding Registers. 04 (0x04) Read Input Registers. 05 (0x05) Write Single Coil. 06 (0x06) Write Single Register. 15 (0x0F) Write Multiple Coils. 16 (0x10) Write Multiple registers. 20 (0x14) Read File Record. 21 (0x15) Write File Record.