Must I get a new GSM phone?

[sn1p3t]

I just bought the SMT5600 with AT&T service. I would like to switch to a lower monthly plan for my limited voice usage, which Cingular offers. Do I HAVE to "upgrade" my phone to another one to get a Cingular plan? Could I "upgrade" to a free phone, and then just use my SMT5600?

[seaflipper]

I just bought the SMT5600 with AT&T service. I would like to switch to a lower monthly plan for my limited voice usage, which Cingular offers. Do I HAVE to "upgrade" my phone to another one to get a Cingular plan? Could I "upgrade" to a free phone, and then just use my SMT5600?

You can do this, but you will have to unlock the phone in order to use it on the Cingular network. That will cost you about $40, about what you might be able to get on eBay for selling the free phone you get for re-upping with Cingular :D

Keep in mind that all of your network settings for AT&T (which will get deleted when you unlock I think) won't work for Cingular anyway. But check here or over at Howard Forums, there are plenty of posts about the correct Cingular network settings for the SMT5600