> I'm trying to rediscover how to control the RS232 UART every PC has two > of. This powerful interface could be more useful, particularly for > process control or robotics. I'm not looking for a driver, unless it is > highly versatile. > > In the original PCs one simply input or output to the UART BIOS address > and the bit field was yours. The DOS driver for the COM ports began the > process of hiding control by adding a new layer. > > Pascal and C can be used to build drivers, such as the terminal driver or > modem driver. > > I am hoping someone in this group has some experience with this in Unix > (Linux). I've reinvented the wheel plenty of times. I wrote a C program not too long ago for the rapid application development of Linux RS-232 automated test, measurement, and control systems. It is stable and is currently being used in numerous commercial robotics and process control system applications. It is also suitable for hobbyists. It is command-line based and it is very easy to use with your favorite scripting language. The program is licensed under GPL, and the documentation can be found at http://sjinn.sourceforge.net/ and the project page is at http://sourceforge.net/projects/sjinn/ Other projects of interest might be Samplin at http://www.iaee.tuwien.ac.at/sensor/samplin/, the Puffin PLC project http://www.control.com/ (open source software for automation), and the Linux Lab project at http://www.llp.fu-berlin.de/. If you are using PIC's, BASIC stamps, or even Lego Mindstorm Robotics Invention Kit :) there are also GPL'd Linux projects for these. If you are interested let me know and I will send you the links.