Originally Posted by weekilter

GSM operators (basically either AT&T or T-Mobile for national carriers in the US) do not care what GSM devices are on their network and is part of the GSM interoperability. On the other hand CDMA operators (Verizon, Sprint and others) generally do not allow BYOD (bring your own device.) On CDMA operators unless the MEID is one that they have sold they will not allow them on their network even though Sprint and Verizon sold units should be able to be used on the other's network.