M025 RS232 / Ethernet converter, Modbus router

RS232 / Ethernet converter, Modbus router

Same as M020, firmware extended by Modbus RTU / TCP routing functionality. Supply 10..35 V DC / 24 V AC. DIN rail mounting, dimensions 90 x 58 x 35 mm


M025 is a RS232 to 10/100 Mbit Ethernet converter,  also called „terminal server“, configurable as Modbus RTU/TCP router.

  • remote Modbus RTU / RS232 device to SCADA Modbus IP connection via Ethernet network

The M025 module is able to connect a Modbus RTU RS232 device to a PC with Modbus TCP master via an Ethernet network. Maximum RS232 communication speed is 230400 bps. Default IP address is, subnet mask All parameters are accessible over the web interface at port 80. Default user is root, password dbps. Detailed description of the settings is to be found in digi_manual.pdf. 

The main difference between M020 and M025 is the industrial automation profile selection option for M025. This is the Modbus RTU/TCP router functionality. On the  TCP side the modul acts as slave (server) and sends the requests as master (client) to the serial line with Modbus RTU. 

The module parameters and functions are configured over a secured web communication (HTTP / HTTPS protocols). Default IP address is, or use configuration utility which is available at www.rcware.eu, Download, Software, Digi utility. Power presence is indicated by a green LED close to the serial connector. The Ethernet connector provides two LEDs: Link and Network activity. The network switches automatically between 10 and 100 Mbit/s. 

The Modbus RTU slave at RS232 with CANON 9M device connects through a nullmodem („crossed“) serial cable with CANON 9F connector at both sides. A CANON 9F device connect through a modem („straight“) serial cable with CANON 9M and CANON 9F connectors. All RS232 signals except for RING (TXD, RXD, RTS, CTS, DTR, DSR, and DCD) are transmitted.