I’m back to using a Treo 650 (GSM, Cingular) for the time being (yet another long story). I "acquired" this one from someone who was a AT&T subscriber. Even though the phone is branded as Cingular, it is locked to AT&T (blue) SIM cards only. So, when I put my Cingular (orange) SIM card in, it refused to get on the network.
I read a couple places that if you had a Cingular Treo, you could call them and request the code to remove the subsidy lock, if you provided a good excuse (such as travelling abroad, needing to use another SIM). Even though this was a Cingular phone and I just wanted it unlocked so I could use it with Cingular service, I figured they might question the origin of the phone and put up a hassle.
So, I decided I would try a for-pay unlocking service. I found several places that would do it by mail for $40 or $60. Being incredibly impatient, I wanted something quicker, and found some online unlocking services. The one I chose to go with was www.650unlock.com.
To do the unlock, you download an application to your machine, connect to the Treo over USB, extract the IMEI number, and verify that the phone can be unlocked. After this, you purchase a $15 unlocking license that allows the program to generate you the unlocking code. This is a sequence of digits, "#", and "*" characters that you type into the phone.
I was extremely happy that it worked and didn’t waste my time or money (or break the phone). I can now use my Cingular orange SIM card (or any other SIM card for that matter).
Don’t tell anyone I had to use my wife’s Windows box to do it, ok?