Samsung Vibrant and Captivate

In the realm of GSM smartphones, there's a phenomenon known as "SIM unlocked," which is the ability to use any SIM card in a phone, meaning you can easily swap from carrier to carrier. And it's pretty rare in the United States. If you buy a myTouch 3G, it's locked to T-Mobile. Same goes for the Motorola Backflip on AT&T. They're both GSM phones and share radio frequencies, but they're locked to the carriers. (The Nexus One is one of the few SIM unlocked phones available -- erm, once available -- in the U.S.)

In order to use one GSM phone on another's carrier, you'll need an unlock code. And obtaining that code (or cracking it) really isn't new. Been doing it for years on the Windows Mobile side of things, and there are websites that will unlock your phone for a small fee. (Or, if you're in good standing with your carrier, it may give you the unlock code.)

Now let's turn to the AT&T Captivate and the T-Mobile Vibrant. Both Samsung Galaxy S-class phones are of the GSM variety and share radio frequencies. And it turns out that the unlock codes are stored on the phones themselves in a hex file, and the fine folks at XDA Developers -- mad props to dagentooboy,, marcopon, Bowsa2511, RazvanG, chcp0112345 and galaxysguy -- have made it dirt simple to extract your phone's code and SIM unlock the beast. And even better is that you can relock them for warranty reasons if need be.

We've done both of our phones, and they worked just fine (though we're only getting EDGE on the Vibrant, for some reason). It's a pretty big step in the name of openness, since buying unlocked phones (which also would mean unsubsidized -- read: more expensive) is pretty much non-existent in the states.

Hit up the XDA Developers link for all the details, read the instructions, and get to unlocking! [XDA Developers via Engadget]


Reader comments

Samsung Vibrant, Captivate SIM unlock codes are hidden on the phones


Nothing new coming from europe that's old news. Just unlock them right away carries and stop being a pain in the butt. Shit like that isn't in europe. Every phone you get is unlocked. What a bunch of bs in the us. And it is easy to unlock them. Just tell your carrier you need to go to europe and they unlock the phone.

That's fine. You keep your high tax rates and we can keep the harder-to-unlock devices. I would take that any day over high tax rates.

That's strange. I saw a similar article over on engadget, only 3g worked on the Vibrant and not on the Captivate.

AT&T & TMobile use different bands.

T-Mobile has 1700/2100MHz bands
AT&T has 850/1900MHz bands

Vibrant GSM quad band 850/900/1800/1900MHz with EDGE
3G HSDPA/HSPA 7.2Mbps on T-Mobile's 1700/2100MHz bands

Captivate GSM quad band 850/900/1800/
3G HSDPA/HSPA 7.2Mbps on AT&T's 850/1900MHz bands1900MHz with EDGE

As a result you can only get Edge on the alternate carriers.

Just like if you took an iphone and used it on Tmobile, you will only get Edge.

Hooked up my friends vibrant work on rogers.

Couldn't unlock it for some reason but was able to use the code to lock it to rogers instead.

..."buying unlocked phones (which also would mean unsubsidized -- read: more expensive)"...

Really? I dare you to do an honest comparison! Add the cost of an unsubsidized phone with a service that does not subsidize phones - choose a service; don't choose an all-you-can-eat service, choose a service that covers what an average user REALLY consumes.

Now factor-in that during the period of the subsidized contract, you cannot use YOUR phone with any other carrier. Moreover, carriers eat away at precious apps memory by putting mostly useless bloatware and some even disable features YOU're PAYING FOR!

Do your readers a favour and do an honest comparison. For me the conclusion is simple: I'll take an unsubsidized phone any time - power to the people!

You don't get discounts on service with most carriers for full price phones. If they charged less, it may be worth it.

Here is my honest comparison for the purchase of my unsubsidized NexusOne.

Subsidized - Phone $179 ($196 including tax) + $79.99/mo (plus taxes and fees = $90/mo) 500minutes/unlimites text+web= $1080 for 12mos + $196 = $1276 for the first yea (plus I am locked into a 2 year contract with a cancellation fee)

Unsubsidized Phone $529 ($580 including tax)+ $60/mo (NO taxes or fees) with Unlimited Talk/Text/Web = $720 + $580 = $1300 just $24 more than subsidized and no contract.

But the second year is where you really get the savings

Second Year Subsidized phone contract = $90x12= $1276

Second year Unsubsidized NO contract = $60x12=$720

$556 in savings from subsidized contract and plenty enough to purchase a new Unsubsidized phone! Of course I don't need a new phone because I got the nexus one and it rocks!

Phone contracts seem messed up and expensive in the US. How should buying an unlocked phone and a SIM-only contract work out cheaper than getting a subsidised phone and, in return, being locked in? (I know it can, it just seems wrong.)

In T-Mobile in the UK, you could get the Galaxy S for free on a 2-year £35/month ($54/month, inclusive of taxes) contract which gives 1200 minutes, 500 texts, unlimited (3GB FUP) Internet and a "Flexible Booster", which you could use for unlimited texts or several other options. It's standard to get practically any phone free on £35-40ish tariffs.

Alternatively, you could buy the phone for £420 ($651) and get a £25/month ($39/month) 12-month SIM-only tarriff, giving 1200 minutes, 500 texts, a Flexible Booster and no inclusive unlimited Internet. Although you can use the Flexible Booster for Internet, you only get 1GB then, can't use IM on it, and can't use the booster for something else.

Over 2 years:
Subsidised: £0 phone + £840 tarriff = £840 ($1303)
Unlocked + SIM-only: £420 phone + £600 tarriff = £1020 ($1582)

So I've can save £180 ($279) and get inclusive Internet in return for locking myself in for twice the time. Fair trade-off for me.

It's true t mobile usa phones normally don't get 3g in europe. What is a bummer. You basically need to get a at&t phone. And same when you get a phone in europe you can use it in us but only get 3g on at&t.

Engadet said they got 3g with the vibrant on AT&T but edge on Tmobile using the Captivate. I'll be trying this out tomorrow when I see my friend with AT&T. If I can get 3g with AT&T on my Vibrant that would be awesome.

The Captivate and AT&T use 850mHz and 1900mHz for 3G so you will not be able to use 3G with the Vibrant unless there is a 1900mHz tower in the area.

EDIT: fixed a mixup

Correct. Its my understanding that their 850 band is far less used than the 1900. Im in Phx and am yet to find any 850 towers here.

Cool. In Australia Telstra's network has a much larger coverage of 850 band. I bought a Captivate on ebay as soon as I found out about this unlock method.

I plugged in my buddy's att sim card from his iphone and got 3g att signal on my vibrant. Since I was at work, where I never get 3g on tmobile, I was a bit excited. I'm thinking I may kill tmobile and get at&t sim for my vibrant. I didn't like the look of the captivate so this unlock is awesome. I get the phone I wanted and a decent network.

A.T.&T. Captivate:
A.T.& T. will Absolutely NOT Unlock my Captivate.
First I was told I must wait 90 days on the two year locked in contract. After 90 days I went back to the AT&T store (Diamond Center Mall, Anchorage, Alaska) to try again. There best tech & the store manager could not get there rep. (on the other end of there phone conversation) to get the unlock code. Twice. NO WAY, NO HOW, for NO BODY is AT&T going to unlock my Captivate phone. EVER!
The reason I was given was, it is the way AT&T + Samsung set up there exclusive rights to sell the phone.
I need this phone unlocked so I can use it in Ukraine, on vaction, they knew this fact, as well.
So trying the legal/proper ways did not work.
Now I am forced to go underground into the back allys.

Hello my new friends.
I am here for the long haul.