GSM phones can be "locked", that is made to accept only SIM cards belonging to a specific network. Typically, this is done so that phones will work only on the network of the carrier. SIM-locked ...

With LTE being built off of GSM and HSPA standards, and not CDMA standards, LTE networks do require SIM cards. And since most major carriers and countries around the world have adopted LTE over ...

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 ...