Decode

If phone was on ATT/Cingular originally, then you can buy UnLock code off ebay or net. If it is an older old BLUE ATT network, then the phone must be unlocked my using downloadable software you can use youself with an XP or earlier PC with an USB port. I don't know of any one selling unlock codes, based on phones IEMI code, that would work. Or at least get a guarantee if someone offers you this. If it is an ATT/Cingula or T-Mobile phone, then it can be unlocked using a code sent you base on IEMI number.

Google phones model and UNLOCK to find free downloadable software. This will also work on any HTC Typhoon phone, which the Audiovox SMT5600 is just one of many carriers that sold it.