Use Your Cell Phone as a Modem for Your PC

Picture this: You're on a commuter train with no access to a Wi-Fi hotspot, landline, or ethernet connection, and you have to get online now. Hey, is that a cell phone in your pocket? Then you may be just a couple of clicks away from the Internet.

Many of today's handsets pull double-duty as a phone and as a modem for connecting notebooks and PCs to the Internet. With a few noteworthy exceptions (can you say "Bluetooth"?), setup is quick and easy. All you need is a phone with modem circuitry enabled, a wireless data-access plan that supports using the phone as a modem, and software for your computer.

AT&T, Sprint, and Verizon sell monthly data plans designed for people who want to use their phone as a modem (a practice sometimes referred to as "tethering"). If you use your phone in this manner on a standard data plan--not the carrier's phone-as-modem service--you may incur additional fees (for example, charges per kilobyte of data transferred). Though T-Mobile doesn't offer phone-as-modem service per se, you can use its Dash, its Wing, or any of a few other handsets as modems. You're on your own for tech support and drivers, but abundant tips are available at Howard Forums and About.com's Mobile Office Technology guide.

The carrier typically provides free drivers as downloads from its Web site, or on a CD. If the service's tethering application doesn't work with your cell-phone model, try a third-party program. June Fabrics' PDANet runs on Palm and Windows Mobile phones, while MobiShark's Shark Modem supports specific BlackBerry models. If you plan to use your cell as a modem only occasionally and are already paying your carrier for a monthly data plan, one of these apps may help you avoid extra fees for using your handset as a modem.

Most cell phones connect to a computer via USB cable, and many PDA phones come with such a cable. If yours doesn't, you will have to spend about $20 for one, or rely on a wireless Bluetooth connection. I used USB cables to connect phones from AT&T, Sprint, T-Mobile, and Verizon to a laptop running Windows Vista. See "Connecting via Bluetooth" for details on linking by means of Bluetooth. If your cell phone supports high-speed 3G data service, and you're in an area where it's available, you'll get download rates of 220 to 700 kilobits per second, comparable to slowish DSL. T-Mobile hasn't yet deployed 3G technology; its EDGE service is only slightly faster than dial-up. If 3G is not an option for your phone, the connection slows to about 50 to 80 kbps, about the rate of a dial-up connection. Of course, in a pinch, dial-up speed is better than no connection at all.

Any calls you receive while using your phone as a mo­dem will go straight to voice-mail. And if you place a call, your modem connection will end automatically.