> He could pry the GPS receiver > apart and find if the GPS receiver spat out NMEA with an RS-232 > interface before the USB circuitry built into it, and a search yielded a > few pages that hinted that it was possible. To me, it wouldn't be worth > the effort or the risk.
I seriously doubt that. On all the USB chips my design team worked on the UART is incorporated onto the USB chip. As Scott mentioned, the USB protocol is a little complicated and in order to have the USB signal meet the proper signal integrity and format, it is imperitive that the UART be on board, especially for USB1.1 and USB2.0 full and high speeds. Moreso for USB3.0 which already in test. That was not necessarily the case for the early (circa 1995) low speed devices like mice. But even then everything we designed after 1996 had the UART on board. Larry K7YBZ
