If you have a broadband internet connection in your home [or is that "boat" in your case Jim?],
you can put a Ethernet card in your Tivo [turbonet] and Tivo can use that to connect to Tivos site for upgrades and guide data - much faster/better etc than dial up.

But of course you need a Ethernet board in your Tivo and broadband [always on] internet at home, plus some sort of in-home LAN.

If you've got a series 2 Tivo, soon, you won't even need to pop the covers to put your Ethernet in - just add a supported USB Ethernet adaptor and away you go.