Are you serial devices left out in the cold and can’t communicate over the telecommunication network? If you have a serial device and need to move serial (RS232, RS485 or RS422) data over the LAN, you can do so with a Serial-to-Ethernet converter. By turning a serial device into nodes on modern TCP/IP networks, these converters help meet the connectivity and conversion challenges and allow them to be directly accessible from the network. More commonly, industries need such devices with added security functions to remotely control, monitor, diagnose and troubleshoot equipment over a telecommunications network. Several advantages to using them include communication to multiple serial devices at the same time across a network and cable replacement.
If you want to have a detailed look at the design of Serial to Ethernet Converters, here are some ready-to-use reference designs from the industry with full documentation:-
UART/SPI/IIC To Ethernet Bridge:
Freescale offers a reference design for connecting your old MCU projects to the internet. It is a serial-to-Ethernet bridge which bridges UART, SPI and IIC to Ethernet easily. The design is built using the MCF51CN128, the open-source RTOS FreeRTOS and the TCP/IP stack LwIP. The microcontroller used in this application supports Ethernet-based connectivity. This implementation includes a small memory footprint web server and TCP/IP socket-to-serial communication for a low-end Ethernet-based microcontroller solution. Board schematics, layout, and gerber files are provided. More on this reference Design
UART to Ethernet Gateway for IoT:
This reference design from Atmel is intended for IoT applications or other scenarios which need both UART and Ethernet. The Gateway features one TCP server, one TCP client and one UDP server. This design describes how to use the LwIP stack to design a UART to Ethernet Gateway. Complete details are provided to help users make their own Gateway easily according to the real requirement. More on this Reference Design
Tiny Serial-to-Ethernet Module:
This tiny Serial-to-Ethernet Module from TI offers a complete, ready-to-implement solution designed to add web connectivity to any serial device. Applications include products that only contain a serial port for a configuration or control interface. In addition, some newer computers, especially laptops, do not necessarily have serial ports, and a serial connection is limited by cable length (typically 10 m). Simply installing a Stellaris Serial-to-Ethernet Module into the legacy serial device provides many benefits including no major board redesign or software changes, easy sharing on a network other than Ethernet, tiny form-factor, and 10-meter maximum cable length for serial connections is no longer a limitation. More on this Reference Design