ASP and ISAPI or ASP.net or ????

I need to control a hardware device from ASP. I have done this a while back (5 years ago) using ISAPI... as I recall it was the only option I had to control a device on my serial port from ASP.

I am about to write a similar app and I want to know if there is a better way to go about this now? Will ASP.net allow direct communication with the serial port? Is ISAPI still a decent solution?

Also, the code which handles the communication is already written and tested. It exists as a stand alone app today... I just need to web enable it. It was all written in C++. C++ is my language of choice.

Thanks in advance!