Yes on a GSM network you should have simultaneous voice and data (assuming that network itself supports it).Instead of creating a new topic, I'd thought I post here.
Will an unlocked verizon cdma 5S being used with Tmobile or AT&T be able to have simultaneous voice and data then?
It looks like the 5S has the same exact radios with both GSM and CDMA 5S but the CDMA one just has the extra CDMA network.