Buying Used Phone Quandry
December 10, 2009 5:54 AM   Subscribe

Can a phone used with AT&T as a service provider then be used with T-Mobile? What does unlocked even mean?

I prefer buying used phones or cheaper phones for kids, as they are hard on them. It seems each week there are new features and options, but we have a plain phone plan for calls and texting.
posted by readery to Technology (4 answers total) 2 users marked this as a favorite
Cell phone service providers often "lock" the phones that they sell to you so that you can only use it with their service. This makes sense for phones that they have subsidized in exchange for you committing to a certain contract.

Unlocked means the phone can be used with any provider. Some phones can be purchased unlocked, but all phones can be unlocked with the right code. Sometimes your provider will be willing to just give you this code; when I left the US and had to switch off T-Mobile, they were really nice about giving me the code. (It probably helped that I had a pay-as-you-go phone which they don't subsidize much, and I had used it for a year). But when I called Rogers (the terrible Canadian provider) about a phone that was some 6 years old, they refused to even consider unlocking it.

So instead, I'll find an online service for unlocking - it's such an old phone that it should only cost about $5. I'll pay someone for the code (which is worked out from the IMEI number inside), and then unlock it myself.
posted by jb at 7:13 AM on December 10, 2009

Oh - by locking, I mean that the phone is programmed to only work with SIM cards from one provider. Though it turns out that T-Mobile US phones will work with a T-Mobile UK SIM card, even when locked.
posted by jb at 7:15 AM on December 10, 2009

I've gotten AT&T to give me the unlock code for my old phones, so that I could give them to my non-AT&T friends. If you are a T-Mobile customer, though, they may not be so kind.

I've also had a Rogers-locked phone unlocked by a sketchy cellular store in a bad part of town for a few dollars.
posted by Mountain Goatse at 7:41 AM on December 10, 2009

So do I understand that you currently have a monthly plan with Tmobile?

If that's the case, you can purchase a cheap prepaid phone directly from Tmobile and just put your current "postpaid" Tmobile SIM chip in it, no unlocking required. Tmobile prepaid phones start at $20 direct.

Both Tmobile and AT&T use GSM technology, but are locked to their prospective carriers. Some phones can be difficult if not impossible to unlock.

Another option if you want to purchase a phone outright is to find one that is unlocked out of the box, like these. You can use an unlocked phone on either Tmobile or AT&T just by putting the correct SIM card in.
posted by SteveInMaine at 10:33 AM on December 10, 2009

« Older What can you do to aid in the digestion of a whole...   |   Random piece of pork belly needs route to my... Newer »
This thread is closed to new comments.