What is a SIM card used for? A SIM card, or a subscriber identity module/subscriber identification module, is a tiny memory card that contains unique information and is linked to a particular network ...

Does anyone know or have first-hand knowledge about installing a Verizon SIM card of an A840 into an unlocked Motorola V635 -- In other words, will the unlocked V635 work in the U.S. using Verizon's ...

After you purchase and use your cellphone for an extended period of time, you can change networks. However, the phone that you're currently using may not be offered on that network. If you wish to ...