| GSM stands for Global System for Mobile | | | | way, connected to each other and each other |
| Communications. And an Unlocked Phone is a GSM | | | | only. So if you're on the CDMA / iDEN network |
| cell phone that accepts the SIM (Subscriber | | | | and want to shift from say Verizon to Sprint (or |
| Identification Module) card of any compatible | | | | to Nextel), the most direct option you have is to |
| network carrier. | | | | buy a whole new cell phone for that new carrier. |
| Which means, if you have a GSM phone like Sony | | | | It's for this reason that those who continually |
| Ericsson P990i or Motorola RAZR V3 from | | | | "hop" between multiple carriers and do not want |
| Cingular (a GSM-compatible carrier) and you decide | | | | to be bothered with compatibility issues, Unlocked |
| one day to shift to T-Mobile (another | | | | GSM Phones from Cingular or T-Mobile are the |
| GSM-compatible carrier), all you have to do is to | | | | way to go. The only downside to this is, if you |
| remove the SIM card allotted to you by Cingular | | | | buy your phone from Cingular, all the features, |
| and load in any active SIM card from T-Mobile. | | | | services and buttons on the phone are already |
| That way, you don't need to buy a new phone if | | | | pre-configured to those offered by Cingular. So |
| you plan on using a different carrier. All you do is | | | | when you decide to use that same phone with |
| change the SIM card and you're on the other | | | | T-Mobile, those features (from Cingular) would |
| network, seamlessly using their services. | | | | technically be disabled on that new network. |
| However, this system doesn't work with CDMA | | | | But that's a minor downside to the flexibility and |
| or iDEN phones -- the two other kinds of wireless | | | | convenience that unlocked phones offer. And with |
| services. That's because, when you purchase | | | | the number of free cell phones (and almost free |
| these kinds of phones (from Verizon, Sprint and | | | | cell phones) available in the market, it shouldn't be |
| Nextel), your phone is basically "locked into" the | | | | hard to find the perfect fit between using your |
| service provider's database system and | | | | phone as-is with your default carrier, and making |
| parameters. The phone and the service are, in a | | | | it work with other services as well. |