I'm not up on all the cell phone stuff,this is what little I do know about our area.We have Verizon towers and AT&T towers.Verizon of course is cdma AT&T gsm.With some of these pay as you go phones,cdma models can get a signal almost anywhere in the county,GSM cannot.You can be at the foot of an Verizon tower with an ATT (gsm) phone and not get one bar,on the other hand with a CDMA you get full bars at either tower.A regional cell company here called Carolina West nearly has a monopoly on all the towers,and they use cdma,that's another reason cdma is so prevalent here.