In the past two decades, legacy serial communication protocols such as Modbus have merged rapidly with modern TCP/IP communication, yielding benefits including widely available infrastructures and greater distance, reliability, and speed. The Serial-TCP program (Device Server) bridges your existing Serial COM port and TCP/IP without the need for changing existing protocol. It works seemlessly and transparently, just like a pair of passive RS-232 / RS-485 / RS-422 repeaters, while the difference is that one requires installation of cables and converters with limited distance; and the other simply makes use of the existing computers and networks and a transmission distance that has no limit.
The applications of the Serial-TCP program (Device Server) include extending serial (RS-232, RS-485, RS-422, and TTL, etc.) communication distance via TCP/IP; expanding the capability of your existing TCP/IP control software; and analyzing TCP/IP and COM network with the built-in "Ping", "Resolve IP Address / Host Name", "COM Port State LEDs", and "Data Logging" tools and features. The Serial-TCP program (Device Server) is also very helpful when you are developing your own TCP / COM control software. The Serial-TCP supports all major Windows OS, including Windows 8, 7, Vista, and XP, both 32 and 64 bits.
The Serial-TCP program is a FREEWARE, so feel free to use or distribute it.