consider a trade-in and upgrade to a T-Mobile phone or tablet. Youll need a number transfer PIN for this You may find it ...

A multi-carrier GSM phone with two, three or four SIM cards. Dual-SIM phones are popular with global travelers who use local and foreign carriers as well as people who want a business and personal ...

(Subscriber Identity Module lock) A function in GSM cellphones that restricts the phone's use to a particular cellular carrier identified by a SIM card. SIM locks are used to ensure subscribers ...