I'm pretty sure the Roadmates can't output through the USB port. I know the Maestros can't. With Magellan you would have to use an Explorist or other handheld, because those were designed to output NMEA. I know certain Garmin Nuvi's (2xx, 7xx, and 9xx series IIRC) can be put into a 'test mode' that will turn on its GPS out (although it speaks Garmin, not NMEA, and its a pain in the kiester because its a 3 step process that has to be done each time you want to use it), and most Mio units as well. After I failed finding a way to make my Maestro unit work, I put up with using my old Nuvi 205 until I got my Yaesu FTM-350 radio, which can also output its GPS to the data port.