Florin, the head honcho over at www.c500-unlock.com has finally found a fix for the problem he ran into when SIM unlocking Audiovox SMT5600 Smartphones. Whereas before, the unlock would turn your phone into a paperweight, the unlock process now fully supports the SMT5600.
If you want to use an SMT5600 on a carrier other than AT&T Wireless (and who wouldn’t?), you can purchase an unlock from Florin, and then use the phone on any GSM network in the world (since it’s quad band).
Being able to unlock the SMT5600 for use on T-Mobile was one of my critical criteria, and I’m happy to see that this barrier has been lifted. Thanks, Florin!