Grant,

Sorry about all the TLA'S (Three Letter Acronyms):-). You are correct in that I would like a virtual Com port.

CDC = Communication Device Class
ACM = Abstract Control Model

Here are a couple of links that talk a little bit about how to do it.

http://www.atmel.com/dyn/resou...oc4322.pdf
http://www.atmel.com/dyn/resou...1_3_04.pdf

I was really close with the old demo. I had it enumerating correclty with windows and had a virtual com port. When I tried to open the virtual com port I got to the point where the PC was trying to set the baud rate on the USB device and for some reason the DK3420 wouldn't ack that packet??? I haven't had a chance to look at it in a few days but, will be back on it soon. Guess I'll have to port the code to the new demo.

I know I could use an FTDI chip to do this but, it would be nice to have a single chip solution and have some smarts to run a different protocol via RS485 rather than straight RS232.

Kim

PS I'm diseased alright;-).