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SIM lock:

A simlock, NETWORK-LOCK, CARRIER LOCK, IMEI-Lock or (MASTER) SUBSIDY lock is actually a technical limit built into CDMA and GSM mobile devices by manufacturers to be used by carriers to restrict the usage of these phones to specific locations and/or networks. This is contrary to a phone (retrospectively called SIM-free or unlocked) which doesn't impose any SIM constraints.The reason a lot of network providers SIM lock their handsets is simply because they offer cell phones at a discount to customers in return for for a contract to pay for the use of the network for a given period of time, in most cases between one to three years. This business model allows the organization to recover the price of a phone across the duration of the contract. These discounts are worth as much as hundreds US dollars.

Unlocking Technology:

Normally, a locked phone will display a message if a restricted SIM is used, asking for the unlock code. On modern phone models working on Android mobile phone software, the smartphone will display a message stating “SIM network unlock PIN” or “Enter Network Lock Control Key” if it's network locked. Windows phones should show the message, “This SIM card can only be used on specific networks. Contact your customer service center for the unlock code”. Some other handsets might show a variety of messages for example "Enter special code" or "Enter unlocking code," or in some cases the phone may simply present a message saying that it is locked. Right after a valid code is entered, the phone displays "Network unlocked” or “Network unlock successful”.


On many occasions a SIM-locked phone is offered for sale at a substantially lower cost than an unlocked one mainly because the supplier anticipates income through its service. SIM locks are used on less expensive (pay-as-you-go) units, though deals on higher priced handsets demand a subscription that provides guaranteed income. Unlocked phones have a improved market value.

Unlocking Services:

A certain amount of businesses offer a network unlocking service . This service needs people that wish to unlock a mobile phone handset to provide their IMEI number to a unlocking company and often they will also require the country and cellular network the device is locked to, often sent via email or submitted on their web site. The supplier then will provide (once you have paid) an unlock code for the device. For a few brands for instance Nokia and Samsung a variety of services additionally provide unique remote-unlocking software with instructions, when a cable is necessary to remove the SIM lock at home. Such organizations may email the unlocking code or software which can remotely unlock the unit. The cost for unlocking a phone may differ based upon the network it's locked to and the handset model itself, as each unlock code is unique to each individual handset.

Unlocking Service Providers:

Unfortunately there are lots of dodgy sellers active in the smartphone unlocking industry. As a result it pays to be sure you find a reliable service provider for such a service. To assist with the search for a legitimate company, we've provided a listing just below (and in no specific order) of several legit organisations currently offering such services.

Reputable Mobile Phone IMEI Unlocking Service Providers: