What is a serial to Ethernet converter and how does it work?

A serial to Ethernet converter is a small electronic device that can convert Ethernet IP / TCP packets to RS232, RS485 or RS422 serial data signals and vice versa. It is also sometimes called a serial device server and it comes in different shapes and sizes.

A serial Ethernet converter can have one serial port or it can have multiple serial ports, up to 25 ports or more. The standard panel mount version is the most common, but it is also available with DIN brackets, so it can be easily installed on a standard DIN rail. It is also available as a wireless converter, in which case IP / TCP packets are transmitted over an IEEE 802.11a / b / g network link.

Some serial Ethernet converters have only one RS232 interface and some have one RS232 and RS485 interface, while others have all 3 interfaces (RS232, RS485 and RS422) built in.

So what is a serial Ethernet converter used for?

Typically used to connect an RS232, RS485 or RS422 serial device, such as a serial printer, barcode scanner, scale, GPS, sensor, or any other industrial or consumer device with a serial interface, to a computer over a standard LAN network. The advantage of this is obvious; you can control, monitor and communicate with your serial device remotely from a central computer. No need to walk to the other end of the factory to check your serial device.

How does a serial ethernet converter work?

The circuit inside the converter can convert IP / TCP packets to serial data and also convert serial data to IP / TCP packets, so it works in both directions.

Before you can start using the converter, you must install the driver software on your computer. This driver software is also called virtual COM software because it creates a virtual COM port in your computer's Device Manager when the converter is connected to your computer. Virtual COM software is usually included with the converter, at least if you buy it from a reputable seller.

Below is an example of what the virtual COM port software looks like.

Once the serial to Ethernet converters driver software has created the virtual COM port, the COM port will show up in your computer's Device Manager as if it were a standard built-in COM port, however it is actually the port COM into the converter at the other end of the Ethernet.

Most virtual COM software will also allow you to change the created COM port settings such as baud rate, flow control, parity bits, and stop bits to match your serial device settings. The IP address of the serial Ethernet converter itself can also be changed according to your preferences. Changing these settings is usually done by logging into the converter using a standard web browser.