A multi-carrier GSM phone with two ... and quad SIM phones support three and four carriers respectively. Following is the alphabet soup. See SIM card. THIS DEFINITION IS FOR PERSONAL USE ONLY.

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 ...

(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 ...