Originally Posted by woshiahhao
Yeap, it's for a school project.
I've read that Verizon and Sprint phone uses CDMA and doesn't require SIM card. Is that true? How is the true user verified in that case?
Verizon and Sprint non-LTE devices do not use SIM cards.
Traditionally, CDMA devices in the US do not use SIM cards (Verizon and Sprint are CDMA, AT&T and T-Mobile are GSM).
Each phone has a built in identifier (called an ESN [Electronic Subscriber Number] or MEID [Mobile Equipment Identifier]) on top of the IMEI number that every phone in the world has. The phone is programmed on the computer to connect to a certain network (the APN and such are already filled in and usually not user-accessible on the phone itself, unlike with GSM devices).
Instead of swapping a SIM card, a user will go onto the website of the provider into their account and put in the device's ESN number. The device then provisions itself (known as activation) and is on the user's account.
However, all networks in the US, both CDMA and GSM, use LTE now. LTE is a GSM technology and therefore requires a SIM card to authenticate the device on the network. So even CDMA networks require SIM cards because their devices are LTE capable. Because of this, and because newer CDMA devices also support GSM (for traveling, since few countries use CDMA outside of the US), you can put a GSM SIM card in a CDMA/LTE device and it will work on GSM networks. Some networks, such as Sprint, try to counter this by artificially blocking out US SIM cards from other providers (so you can put in a Canadian SIM card for example and use a Sprint CDMA/LTE device on a GSM network, but the phone will not accept for example an AT&T SIM card).
The way everything is headed though is that everything (calls, text, mobile data) will be carried over LTE. Voice over LTE is called VoLTE.
HTC Evo 4G -> HTC Evo 3D/Nexus S 4G -> Galaxy S II -> iPhone 4S -> Galaxy S II -> Galaxy Nexus -> Galaxy S3 i9300 -> Galaxy Note 2 i317 -> Galaxy Note 2 T889