Real World Instrumentation with Python

Serial Terminal Emulators

When working with instruments and subsystems that employ a serial interface, it is sometimes possible to repurpose some commonly available tools to create a perfectly usable simulator.

One such tool for Windows systems is called Tera Term; this is the tool I will focus on in this section. Originally written by T. Teranashi in the mid-1990s (and last updated in 1999, when version 2.3 was released), Tera Term supports Telnet logins as well as serial I/O, but the original release of 2.3 does not support SSH.

Although there is no longer a big demand for serial terminal emulators, and Tera Term is getting rather dated, it has something that makes it particularly interesting: a powerful scripting language. When combined with a tool such as com0com, it is possible to use Tera Term to create a respectable simulation of a serial I/O instrument and communicate with it from your instrumentation software during development and testing. Tera Term works well at the other end of the communications link as well, and I’ve used it as a functional test driver for an embedded imaging system and a laser interferometer system, among other applications. Of course, I have also used it many times as just a terminal emulator.

You can download Tera Term and get more information about it from http://hp.vector.co.jp/authors/VA002416/teraterm.html. The source code is freely available, and there are some add-ons available as well. Check the website for details.

Installing Tera Term is easy. ...