Take the shackles off your cellphone

This article has been updated. The original version, published in the June 2004 issue of Popular Science, discusses outdated technology and services.

Tired of being locked into a single carrier? While number portability offers some freedom, your phone remains tethered to its original provider due to carrier subsidies. This prevents switching until the provider recoups the discount offered at purchase.

• Project: Cellphone Unlocking
• Technology: SIM unlocking
• Cost: Free to $50
• Time: 15 minutes
• Difficulty: Beginner to Advanced (Editor’s note: 1/5)

But liberation is possible! GSM phones can be unlocked, allowing you to switch to any GSM carrier (e.g., AT&T, T-Mobile). Unlocking also enables international use on local networks, avoiding roaming charges, or even using a foreign phone domestically. Have an old phone? Unlock it for backup use.

The key is the SIM (Subscriber Identity Module) card, containing carrier, number, and contact information. Unlocking lets you simply swap SIM cards for easy carrier or phone changes.

Unlocking requires a special code (see "Unlocking Your Phone," below). For Nokia phones, free unlocking software is available at unlockme.co.uk, or request the code via their forums.

For other manufacturers, gsm-software.com provides codes for a fee ($10-$20). Some phones require a data cable and specialized software.

Caveats exist: GSM networks use different frequency bands (see below), so single-band phones may have limited coverage. Also, carrier-specific features (e.g., picture messaging) might not function.

Unlocking Your Phone

We unlocked a Cingular Nokia 3595 using a prepaid Vodafone SIM from New Zealand. The image below shows the phone before unlocking. We obtained unlock codes from unlockme.co.uk using the phone's serial number and carrier information.

• Code 1: pw 197824120263746 1#
• Code 2: pw 807711135262232 7#

1. Power on the phone without a SIM card.

2. Enter the first code, using the * key to access the p, w, and symbols.

3. Upon successful entry ("Restriction Off" message), insert the Vodafone SIM. The phone should search for a signal.

Frequency Bands

• AT&T/Cingular: 850/1900MHz
• T-Mobile: 900/1900MHz
• European: 900/1800MHz
• U.S. Tri-band: 850/900/1900MHz
• European Tri-band: 900/1800/1900MHz
• Quad-band (World Phones): 850/900/1800/1900MHz

More Cellphone Hacks

Numerous cellphone hacks exist, such as adding games, custom wallpapers, using MP3s as ringtones, or (strongly discouraged) unauthorized service access.

Explore cellphonehacks.com for phone-specific forums and tutorials. While many threads are filled with boasting, useful how-to guides can be found.

I successfully modified my Verizon LG VX4400 using a $23 data cable and BitPim software. This allowed modem use, Verizon banner removal, custom wallpaper, and ringtone changes—a taste of the possibilities available to more experienced users.

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