You may want to consider the type of lap top you select to use. The IBM T43 laptop entrusted to me by my employer has a large fancy connector on the bottom that can engage with a docking station. The standard IBM docking station incorporates fully legacy compatible serial and parallel ports.

It would be interesting to query about just what your usage requirement is for a "real COM" port. What is the critical aspect?

I have done many many serial port things now with Windows apps written in C++ and in various flavors of Visual Basic and have had little to no trouble with generic ports versus USB serial cable ports. I have said before that there is a quite wide variation of quality and robustness of the Windows drivers that come with USB serial cables. Today I will generally only use adapters with the latest chips from FTDI and use the latest version of the drivers from their web site.

I may add that the sheer speed of today's computers also helps to eliminate many of the older strange problems of talking to COM ports with software that is isolated from the hardware like you are in Windows. This same comment applies equally to legacy or USB type COM ports.

Michael Karas