How to support two (dual) USB ports?

[spcw1234]

With this kind of a configuration can't I program each of the PICs with PBP to download the temperature readings from their respective USB ports without having a "Host Mode"?

USB requires a host. The PIC using the on-board USB or a USART to USB interface, and your temperature sensors are not capable of doing this. The VNC2 that Darrel linked to looks like it might work for your application though.

They even have precompiled rom's available. This one looks like it will do what you need, it is a USB host bridged to a UART port.

http://www.ftdichip.com/Support/Docu...ost_Bridge.pdf

[jellis00]

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??