Communication between two serial devices via a serial interface (RS232, RS485, or RS422) has a limitation of distance (the distance is limited to 15m for RS232, and 2km for RS422/RS485). Serial Tunneling allows us to overcome this limitation. With Serial Tunneling, two serial devices can communicate with each other from anywhere.
Each Serial device will connect to a Serial-to-Ethernet or a Serial-to-WiFi converter. Two serial converters will connect to each other (TCP server-client model) via a local LAN/WLAN, or even the Internet. Two serial converters can also connect directly to each other via an Ethernet cable. This creates a serial tunnel between two Serial Devices.
Further more, the Serial tunneling is NOT ONLY created between two Serial Devices BUT ALSO created between a serial device and a serial software on PC. In this case, we provide a free software (namely ezVSP) that acts as a virtual serial-to-Ethernet/WiFi converter for your serial software
In the case serial device uses Modbus RTU, the Modbus Gateway should be used instead of general Serial Converter.