I tried greating a short route using Mapsource then sending it to a Nuvi 660 (a venerable antique but still good stuff). All the Nuvi picked up was the start and finish points as custon POIs. The Nuvi then plotted a route similar to the one I'd selected with Mapsource. As far as I know, only devices sold with a copy of Mapsource (Zumos I believe) can accept routes. Anyone who knows better is obviously encouraged to illuminate us.