The size of a deck of cards, it plugs into a PC, which needs a broadband Internet connection. The device then detects when a compatible cell phone comes within 8 feet, and places a call to it. The user enters a short code on the phone. The phone is then linked to the magicJack, and as long as it's within range (YMax said it will cover a 3,000-square-foot home) magicJack routes the call itself, over the Internet, rather than going through the carrier's cellular tower. No minutes are subtracted from the user's account with the carrier. Any extra fees for international calls are subtracted from the user's account with magicJack, not the carrier.

what about Vonage for cell phones? If you have unlimited data, then that is all you need.