I am thinking of buying an unlocked GSM phone. I've been looking at Sony Ericsson and a few others, but I have some technical questions on what all it means to have an unlocked GSM phone. I understand the basic concept, but I keep seeing some inconsistencies with the details. For one: I see carrier compatibility issues with different phones. I've found a whole list of carriers with GSM compatibility in the US (AT&T, T-Mobile, Cincinnati Bell Wireless, ECT...). Now, does that mean that if I own, let?s say the Xperia x10a, I can use any GSM carrier? Will that vary from phone to phone? Will any GSM carrier accept any unlocked GSM phone? Also, if I own an Unlocked GSM phone with 3g and Wi-Fi capability, and dont want to pay for the mandatory data plan because I can do just fine with Wi-Fi for my needs, can I do that? Will that depend on the carrier? That's the big one for me. Any help on these questions would be greatly appreciated. Thank you in advance.
If you get an unlocked GSM phone, you can indeed use it with any GSM provider, regardless of model and brand. These days they're all quad band world phones so you no longer need to worry about supported bands for voice calls and EDGE (slow) data.
Unless you contact your carrier and change your plan, you do not need to get a data plan. Carriers only insist on a data plan when you buy one of their phones. However, you will probably want to turn off the cellular data option on your new phone to make sure it doesn't use your carrier's data network instead of WiFi.
-------------------- Lisa Gade Editor in Chief, MobileTechReview
Thank you Lisa. This really helps me to better understand my options. I was hoping this was the case, but started to get worried when I began reading that AT&T was somehow scanning its customers phones and arbitrarily adding data plans to people they deemed as using "Smart Phones" whether they were "branded" or not. So, either way, I have options. Thank you again and please keep up the great work. I am a big fan of your site and think your reviews are fantastic. I will certainly vet out my hardware options here before I make my purchase.