The Serial Slave mode is used to connect one or more serial ports with the internal registers . The external devices connected to the serial ports are modbus masters and the terminal acts as a modbus slave.
A connection between a master serial port and internal registers is configured using a row in the form. Access to the internal registers is enabled using the check box.
| Port | Serial port number in the range 0 to 1. |
| RTU ID | Modbus address in the range 1..247. |
The example in this figure shows two serial masters accessing internal registers. The RTU ID on the form is set to 1 and is enabled using the check boxes.