MSDOS-based RS232 programs do not work on this laptop but OK on an old Dell 200MHz pc. Trying to use COM1 port which tests OK (pc diagnostics). On some MSDOS programs there is some sort of ASCI symbols being transfered. On others, nothing, either way. Perhaps the COM1 pinout is different for IBM vs Dell?

That's unlikely - it's a hardware standard, shouldn't vary from machine to machine. Not all old DOS programs work with newer operating systems. Are you booting to DOS or just using a 'DOS window'?

Have you configured the COM port with the mode command (see below). Check out dos help for info. mode/data/parity/retry A common mistake is to leave data set to default (which is 7) and your graphics are then a mess. Check the autoexec.bat on the original pc to see how that was set up. Good luck - keep us posted.

I may be confused here. However, I believe RS 232 is the designation for a parallel port connector. So RS232 based programs by defination are supposed to run on the parallel port. What is an example of a program like this?

Fred - The RS232 standard is nothing to do with the parallel port. If you look at the com ports they are usually a 25 or 9 pin RS232 (sometimes called D Type) connecter. The standard set purposes (e.g. TX/RX/RTS/CTS) for each pin, including the voltages involved. Although these are not necessarily adhered to. To use correctly often means having a crossover cable, rather than one to one. Originally, the parallel interface (which I believe was invented by Centronics for their printers) used a parallel connector which had over 30 contacts(not pins), many were not used, and different voltages were used to RS232. It was for reasons of economy that equipement makers bought in the 9 pin RS232 to replace the original 25 pin, and also started using a 25 pin RS232, with a different gender to the regular RS232 connector to replace the centronics interface. Care needs to be taken, not to connect a true RS232 serial device to the parallel port, as due to the different voltages something is sure to fry. And before you ask, yes I have made this mistake. Hope this is of some help. Good luck - keep us posted.