Shawn, I really appreciate your and Darrel's input on this. I reviewed the websites you both pointed to and have some questions.
1) I presume that in my application, the temperature datalogger becomes the USB host and my 18F2550 becomes the slave with a UART that is bridged to by the VNC chip...is that correct??
2) Since my application has to provide an interupt to the temperature datalogger when it wants the latest temperature sent via the USB to my application, how can I get the interrupt to the datalogger....it appears that the total interface using the UART<---VNC<---->USB Host is only uni-directional between the UART and VNC and would prevent me from sending the interrupt to the USB Host via the VNC. Don't quite understand how I am going to handle that if I use VNC. Can you elaborate??