Mark,

>I would like to have two processes in the form that are reading different com ports. I dont have a problem reading port. But my problem is that I am using do while inside of the code that reads from a port. So when I start first process I cannot start the other. Any idea?
>

3 methods come to mind, assuming you are using MSCOMM32.OCX.

Use the control's ONCOMM event. Place your processing code in that method. With the RThreshold property set to 1 or greater, this event fires with each character received.

Use timer(s) as necessary to poll the ports for data.

Use a combination of the above 2. This file uses this method.

DO WHILEs are to be avoided, IMHO.