Cellphones w/o SIM cards-- how do they work?

What do verizon/sprint cellphones that do not have SIM cards have in place of SIM cards? And how does that work?

Cellphones w/o SIM cards-- how do they work?
They just have a protected area of memory on the phone itself that performs the same kind of functions as a SIM card. Phones from Verizon and Sprint can program themselves over the air -- they identify themselves by serial number to the network and the network sends the identity information back to the phone to be stored.





In contrast, on a GSM phone the identity information is stored on your SIM card, which gives you the advantage of portability between phones and of using a different card if you need to.
Reply:Sprint and verizon phones do not use any thing at all. What they do (at activation at a store) is....ok every phone has what is called an imei...its like a social security number for phones. At activation they scan the imei to the number that it needs to work with and voila. It magically works. They do this so that no other company can use their phones (unlike atnt or tmobile), so when u break ur phone you have to buy a new one from them....its basically so that they make more money...they also do it so that other people can't use their number on your phone unless they take it to a store...but if the phone is reported missing then they are screwed. With sim or "gsm" phone you can unlock them and swicth phones all you want as long as you take the sim and put it in the phone. Not good for the person that loses their very expensive phone unless they have insurance. Gsm phones are what the rest of the world uses...that's why u can travel with a atnt or tmobile phone and it will work while sprint and verizon won't.
Reply:there the same as any the thing is when u wanna change ur hone cuz u lost it or w/e the reason is u either have to call them or go on their website to change it not like a sim phone were u can just buy it and replace the sim card