Your cellphone is more powerful than you probably know Your cellphone is an amazing device — perhaps more amazing than you realize. It's got all sorts of features, and I'm not talking about playing music or shooting videos. We keep learning about our phones' undocumented features, and the ways they can be used to help or hurt us. Back in January, for example, when Jason Cochran's car was stolen from outside his home in Eastvale, Calif., with his 10-month-old son in it, Sprint was able to track it through the phone's GPS unit. Unfortunately, the comapny refused to disclose the car's location to deputies without their filling out forms and paying a $25 fee. (Despite Sprint's refusal to help locate the boy, he was soon found unharmed.) More recently, during the search for Jerry Cooke, Brian Hall, and Kelly James — the hikers who became trapped on Mount Hood — one of the early hopeful signs came from T-Mobile, James's cellphone provider. It detected his phone turning on and off, although he was apparently unable to make a call. At the time, it was a sign that he was at least alive and trying to send a message. That your cellphone company detects your signal even if you aren't making a call is pretty obvious, of course. The network needs to know where you are in order to route your calls. If the authorities are looking for you (for good or bad), simply turning on your phone could clue them in to your location. And, of course, let's not forget the staple of many a cop show and science-fiction movie: triangulation. It's true. If you're using your phone, you can be tracked by measuring the strength of your signal at different locations. Celebrated hacker Kevin Mitnick was captured in 1995 in just that fashion, and Verizon Wireless uses it to supplement the GPS for its VZ Navigator service. All of these are somewhat obvious, if undocumented, features of your cellphone. But we learned earlier this month that there are some other tricks your phone is capable of — and not simply telling the repair guys that you've gotten it wet. Working with Nextel, we learned, the FBI was able to turn a suspected Mafia member's cellphone into a listening device, although the phone wasn't even turned on. Nextel sent it a signal (presumably when it was on), and suddenly the phones of John Ardito and his attorney became bugs. In this case, the government went through the trouble of getting a warrant for the procedure, though we've learned how much the current Administration hates dealing with those pesky civil liberties. That's not the only way the government can use your phone against you. It doesn't need a warrant to demand that your cell-phone provider tell it where you've been — and thanks to the Patriot Act, your provider can be prohibited from telling you its turned over that information. That's because in December 2005, a federal judge ruled that the government can track citizens' locations via their cellphones without probable cause. Ain't that dandy. Naturally, the government said that this technology would only be used against bad guys ... or people it thinks might be bad guys. Or people it thinks could someday be bad guys. It's not like it has a history of abusing its powers or anything. Like most people, I suspect, I hadn't considered that a turned-off phone could be used to listen to me. (Note to self: Remove batteries before discussing you-kn0w-what with you-know-who.) And I would have liked to believe the Feds would require some oversight before demanding to know where I am at any moment. But things, we're told, are different now. It's for our own good. If all this doesn't give you pause, consider this: Your phone most likely has a lithium-ion battery — the same kind that was catching fire in all those laptops. A special circuit keeps them from overheating and, potentially, exploding. I wonder if that circuit can be disabled with a remote command. Have a nice day. America prevails. Andrew Kantor is a technology writer, pundit, and know-it-all who covers technology for the Roanoke Times. He's also a former editor for PC Magazine and Internet World. Read more of his work at kantor.com. His column appears Fridays on USATODAY.com.