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This story has been updated. It was originally featured in the June 2004 issue of Popular Science magazine and involves outdated technologies and services.

While number portability may have freed your cell digits, your phone is still a ball and chain, locked into one carrier’s service. These subsidy locks keep you from walking away before the provider can recover that big discount you got when you bought the phone.

  • Dept: Void Your Warranty
  • Tech: cellphone unlocking
  • Cost: free to $50
  • Time: 15 minutes
  • Difficulty: dabbler | | | | | master (Editor’s note: 1/5)

But it doesn’t have to be so. If you have a GSM phone, you can unlock it and switch to any GSM network carrier (the big three are AT&T, Cingular, and T-Mobile). You can also take an unlocked phone overseas (most of the world uses GSM) and use it on a local network to avoid paying for international roaming, or even buy a European phone (they tend to be ahead of us in cell tech) and use it here. Have an old phone lying around? Unlock it and keep it as a spare.

The key is the subscriber identity module, or SIM, card, which stores the essential information—carrier, number, contacts—in all GSM phones. So once your phone is unlocked, switching carriers or phones simply means popping in a new SIM (available at any cell store here or overseas).

The phone’s lock is defeated by inputting a special code (see “Unlocking the 3595,” below). For Nokia phones, you can find free software at unlockme.co.uk that will calculate your phone’s code, or just post a request on the site’s forums and wait for a friendly hacker to reply.

If your phone is from any other manufacturer, check out gsm-software.com, which will email you a code for $10 to $20. A few hard-to-crack models require a data cable that sends the phone a code from software on your computer.

Of course, there are a couple of catches: Even within the GSM network, carriers use different frequency sets (see list, below), so if your phone only supports one band, your coverage area may suffer. Also, special carrier-specific features like picture messaging may not work on an unlocked phone. But hey, every freedom has its price.

Unlocking the 3595

We unlocked a Cingular Nokia 3595 to pop in a prepaid Vodafone SIM from New Zealand. The screen below left is what we saw with the new SIM inserted before unlocking. To get the unlock codes, we posted a request at unlockme.co.uk with the 3595’s serial number and carrier. The next morning, we had two codes:

  • pw+197824120263746+1#
  • pw+807711135262232+7#

1. To enter a code, the phone must be on, with no SIM inserted. Our Cingular card was behind the battery.

2. Next we punched in the first code, hitting the * key several times to get the p, w and + symbols (don’t ask why; that’s just how it works).

3. When we finished, a “Restriction Off” message flashed, and when we inserted the Vodafone card, the phone began searching for a signal.

What’s the frequency, Kenneth?

  • Cingular and AT&T: 850/1900MHz
  • T-Mobile: 900/1900MHz
  • European: 900/1800MHz
  • U.S. tri-band phones: 850/900/1900MHz
  • European tri-band phones: 900/1800/1900MHz
  • Quad-band “world phones”: 850/900/1800/1900MHz

Other phone hacks

Just about every cell has its hacker’s bag of tricks—things like adding custom games and wallpaper, using MP3 snippets as ring tones or even (don’t do this) stealing service.

To figure out what can be done—and how—on yours, try cellphonehacks.com, which has forums for each phone company and provider. If you dig through the cell-geek boasting matches that fill many of the threads, you can usually find some how-to’s for your phone.

I got lucky and found sites dedicated to hacking my Verizon LG VX4400 using a $23 data cable from RadioShack and a free program called BitPim. So far I’ve used the phone as a modem, removed the Verizon banner, added a shot of Johnny Cash at Folsom Prison to my wallpaper and changed my ring tone to The Jeffersons’ theme… probably all child’s play to a hardcore hacker, but it feels like movin’ on up to me.

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