Why Buy Unlocked Cell Phones

The GSM (Global System for Mobile communications) is the most accepted standard for mobile phones in the world. It is believed used by 80% of the mobile market or over 3 billion people in more than 212 countries and territories. Consumers benefit from the GSM standard from the capacity to roam and switch carriers without changing phones. Telcos on the other hand are able to select equipment from any of the suppliers employing GSM. GSM also led the way to short message service or SMS. The GSM standard includes one worldwide emergency telephone number, 112. This eases access by international travelers to emergency services without knowing the local emergency number.

GSM mobile phones use a Subscriber Identity Module or SIM Card, to work which can be removed and used in another phone. Phones sold by a network are often SIM locked under a contract as these are often subsidized. Resultantly, the network operator would want to recover the subsidy over the life of the contract. The customer in fact agrees to the "lock-in" just to get hold of a phone that would cost them more in the open market. Pre-pay phones are sold thru mobile phone stores and a variety of retail outlets. Due to the competitive market, they vie for the lowest price that also often has an operator subsidy that needs to be recouped. Thus, these are also often SIM locked. SIM lock is a capability embedded by mobile phone manufacturers into GSM mobile phones to restrict use to specific network providers and countries. 

The data of cell phones that do not operate with a SIM Card are embedded in their memory. A special digit sequence is used to access "NAM" as in "Name" or number programming menu. To prevent accidental disabling of the phone or removal from the network, the Service Provider places a lock on the data called a Master Subsidiary Lock or MSL. This also ensures that the Service Provider is paid for the phone sold or leased. A cell phone that sells for $500 for example may be sold to the subscriber for $200, the difference of which is paid by him in his monthly bill. A carrier who does not use a MSL could lose the $300 difference if the subscriber cancels the service and uses another carrier. The MSL only applies to the SIM and remains in force once the contract is completed. The Service Providers MSL locked by the manufacturer into the phone may be disabled so that it can be used by other Service Providers SIM cards. Any SIM card can be used on suitable mobile phone networks; most GSM and 3G phones can be easily unloked. 

The iPhone of Apple may be considered an exception. Apple continues to wage a war with hackers who  unlock the SIM of its subscribers. Apple comes up with a software to counter that used to unlock its iPhone while hackers come up with as a result with one that will break the iPhone’s lock.

A large number of online and retail businesses now have the ability to unlock a phone so that a different SIM may be used. This favors mobile phone users in general but is more particularly beneficial to international travelers who would want to use a local SIM card when in another country. This would reduce roaming charges.