Previously unlocked S5 help

[Kim Snyder2]

A few weeks ago my S3 decided to commit suicide. My husband gave me his old Moto E to use. This phone stinks, but the battery life is awesome. My Mom gave me her old S5. She bought this phone unlocked, but used it with Consumer Cellular, which I believe is AT&T. I have verizon as my carrier. Does anyone know if I can use this phone? I can change the network to CDMA, but I still cannot get the phone to work with my SIM card. If a phone was unlocked, then used with plan, does it have to get unlocked again? Is this even possible? If it is possible, how do I go about it? Will I ever be able to use this phone with my Verizon plan? I've been carrying 2 phones with me at all times! One for phone and text, the other for pictures and wifi.

 

[Rukbat]

An AT&T phone (even an S5, AFAIK) will have bands LTE bands 1(2100), 2(1900), 3(1800), 4(1700/2100), 5(850), 7(2600), 17(700) (and AT&T uses band 17 almost everywhere) - which is GSM. It sees CDMA signals as noise.

You can change the network (the software part, anyway) to CDMA, but the hardware in the phone is still looking for a GSM signal. (Hold the phone near an AM radio and call it from another phone. That's GSM - bursts of signal. CDMA is a continuous signal. (Sort of - it's in packets too, but it sounds more constant.)

It's like trying to get picture on an FM radio - even if you tune to 88 (the edge of TV channel 6) and hear the program, you won't get the picture (wrong hardware).

(Locking just prevents a "foreign" SIM card from being used. It has nothing to do with the type of hardware the radio uses.)