ATT GSM Phone will not work Non-ATT SIM Cards

[Jaywant]

I bought ATT GSM Service + the newly launched Pocket PC Siemens SX-56 phone. Cool phone and the GSM service works ok in the Bay Area + on a recent trip to London worked well. The only issue is that Siemens SX-56 will ONLY work with ATT SIM Card. I tried inserting a T-Mobile SIM card in the UK - it prompted me for a CODE, which as per the ATT Customer Services agent, ATT will not give out. So essentially you are forced to be able to use the phone *only* where ATT GSM has service or partnerships with foreign carriers (at high rates of $2.99/minute intl calls !!)

Question for all: Has anyone figured out the code required to be able to use the ATT Siemens SX-56 phone with a Non-ATT SIM card ? Any ideas / leads would be appreciated

[HoOn]

You need to unlock your phone. Thats why the non ATT sim card didnt work.

[Matt]

Go to http://www.howardforums.com and search for the user "lvwireless" He (I think his name is Adam) is the only person who can unlock AT&T phones - AT&T won't do it. I think there may be a forum dedicated to this stuff over there.

[yummyads]

on the flip side, is it possible to use an AT&T sim chip in a non-AT&T device? I want to use the chip in a gsm-based handspring phone.

Please cc reply with email if possible (jonathan@adcrobatics.com)

[cryogenic]

Again, this is something that's phone dependent and if the phone is unlocked, you'd be able to use an AT&T SIM in that particular phone. If the phone was bought from T-mobile or Cingular, for example, that phone would be locked and would have to be unlocked. You can get the SIM unlock code from either carrier just by calling customer service and requesting it. I would think you would have to be a customer in order to get it, though. [img]i/expressions/face-icon-small-smile.gif[/img]

[md]

so does anyone know if the unlock code is phone dependent or model dependent.... that is, would one code work in any t720... and then the next question is would the tmobile obtained unlock code for the t720i work for our ATT t720 gsm phone?

[sd]

The code is phone dependent. Not model nor brand nor company dependent. If you buy a phone and i buy the same phone, in the same store, sitting right next to your phone, with almost exact serial numbers, and i get the code for mine, that wouldn't help you any.

[pang]

London and Europe and the rest of the gsm world operate on different gsm bandwidths than U.S. gsm. Check to see that Siemens phone is a tri-band first.

[pang]

Hummm, I checked the Siemens specs and that phone should work there. Tell ATT you want to be able to use that phone with other sims and to give you the code. Otherwise you can always buy another tri=band or a GSM phone with the 2 European bands and use that phone overseas. I have one that I use while in the rest of the world. I always just buy a local prepaid card for each country, makes it cheaper to call around locally and for local friends to call you otherwise they have to call all the way back to U.S. if you're in London and they are in London.

[Simon5282]

Shouldnt all this unlocking and locking be illeagel? It is the cell phone companys way to steal from us. If you buy a discounted phone, they have a right to make you sign a one year contract to recoup thier loss, but they are crossing the line and stealing by carrierlocking (simlocking) the phones.