Unlocked Galaxy S5 wont work on GSM

magenta2326639

    I have a T-Mobile Samsung Galaxy S5 that I have performed a successful unlock (message said successfully unlocked). I am trying to use the phone on Consumer Cellulars network which requires GSM. When I set the network to GSM only (settings/data usage/mobile networks/GSM Only) then check device status (settings/about device/status) it shows network:unknown, mobile network type:unknown, service state:out of service, and mobile network state:disconnected. The only way I can connect to a network is to select one of the network modes that contain CDMA (LTE/WCDMA/GSM, WCDMA/GSM or WCDMA only). Consumer Cellular is telling me this indicates the phone is still locked on CDMA network and isn't operating on GSM. Unless I can get the phone to connect to the GSM (only) network, picture texting will not work on Consumer Cellulars network either send or receive. With one of the CDMA networks selected I can text (no pictures), make phone calls, receive emails and browse the web. I need the phone to work on GSM only so I can get picture texting working. Help!

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      • lpat

        Re: Unlocked Galaxy S5 wont work on GSM

        Verify that your Galaxy S5 is either model SM-G900T (= T-Mobile) or SM-G900A (= AT&T).  T-Mobile and AT&T have GSM networks and Verizon has a CDMA network.  If you bought your phone from T-Mobile, it should be a G900T.  I have a Galaxy S5 G900T, unlocked, and it works fine on other GSM networks (i.e. T-Mobile, AT&T, European GSM networks).  I am unsure about how other US networks work, so can not help you there.  At least verify that your phone is truly a GSM phone.  Find the model number of your phone in the "About Device" (under Settings) and verify that that model number is a GSM phone.  You may have done all of the above already and, if so, ignore my suggestion.

        2 of 2 people found this helpful
          • magenta2326639

            Re: Unlocked Galaxy S5 wont work on GSM

            Thanks for the pointers. Yes the phone is a SM-G900T so theoretically it should be a GSM phone. It's just odd that the only time I can connect to a network is  when a CDMA option is included in the network mode. When it does connect with a CDMA mode it shows that I am on Consumer Cellular's network. Is there some way to tell if the phone is truly unlocked other than inserting a different SIM card - or a way to perform the unlock sequence again? I only have the T Mobile and Consumer Cellular SIM cards.

              • lpat

                Re: Unlocked Galaxy S5 wont work on GSM

                I'm thinking that you should be leaving your phone set to LTE/WCDMA/GSM so that it can negotiate with your local Consumer Cellular network for the supported data transfer mode in your area.  By selecting GSM (data transfer) only, you are forcing the phone to transfer data at GSM/2g speeds.  I think that Consumer Cellular uses the AT&T network, and if the AT&T network in your area has been upgraded to support 3 G (or faster) data transfer and no longer supports 2 G, then your selection of GSM will prohibit a connection.  This is a bit beyond my knowledge, but WCDMA is not the same as CDMA.  From what I learned on a web search, WCDMA has to do with 3 G data transfer, distinct from a CDMA phone used for voice connection.  I did a web search using keywords "difference between GSM and WCDMA" and "manual network mode" and one article explains the difference between GSM and WCDMA data transfer modes.  This is all pretty techy, so I question whether first level tech support at Consumer Cellular would understand WCDMA vs CDMA.  Hope this helps.

                2 of 2 people found this helpful
              • j.a.r.v.i.s

                Re: Unlocked Galaxy S5 wont work on GSM

                Here is a good site to check phone/carrier compatiblity.

                 

                FrequencyCheck - Mobile Network Compatibility Search for Unlocked Phones and Devices

                 

                One thing to note, as ipat said - make sure you use the exact phone model as sometimes they do have different radios/capabilities.

                 

                I usually leave my selection on Auto - LTE/WCDMA/GSM

              • tmo_marissa

                Hey, magenta2326639! Sorry to read about the trouble with your S5. I have to confess, lpat's research and replies here are definitely more helpful than my limited knowledge of what should happen after you complete your unlock could offer. What I can say is that for any part of the other carrier's service to be working, the unlock was successful -- and I do know that we advise users who bring unlocked equipment to T-Mobile that not all services will be compatible, but we offer a list of generic data settings that they can input in their equipment for the best possible outcome. Did you have any custom APNs or data settings that you were able to enter from the new carrier? How are you doing these days?

                 

                - Marissa

                  • magenta2326639

                    Re: Unlocked Galaxy S5 wont work on GSM

                    Thanks Marissa. You sort of hit it on the head. After several phone sessions with Consumer Cellular help (all levels ;<)), it was "decided" that the phone just wasn't compatible with their network for the picture messaging component. I thought this odd as they all stated that the S5 never had any problems normally. As a last resort I requested they send me a new SIM card on the off chance that the one I had was damaged. Got the new one today, installed it and configured the phone and now picture messaging is working, Thanks to all that responded to my post. 

                  • tidbits

                    Re: Unlocked Galaxy S5 wont work on GSM

                    WCDMA is NOT CDMA.  They are two different animals even if they share part of the same name.  WCDMA = UMTS/HSPA and not CDMA as found on Verizon or Sprint which theirs would be EVD

                     

                    these are comparable but are exclusive to their own.  Carriers are swicthing over to GSM for the future of their networks by going LTE, and dropping their legacy networks.