What is a sim lock

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SIM lock:

A SIM-Lock, NETWORK LOCK, carrier-lock, IMEI-Lock or (MASTER) SUBSIDY lock is a technical constraint built into GSM and CDMA mobile phones by manufacturers to be used by carriers to limit the usage of these phones to a particular countries and/or networks. This is as opposed to a cell phone (retrospectively called SIM-free or unlocked) which doesn't impose any SIM constraints.Unlocking a mobile phone is virtually universally legal. At the same time, it's legal for carriers to force SIM locks for certain time periods, differing by location.

Unlocking Technology:

Usually, a locked phone will show a message if a restricted SIM is used, asking for the unlock code. On new phone models working on Android os software, the smartphone should display a message saying “SIM network unlock PIN” or “Enter Network Lock Control Key” if it is 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”. Other models may well show differing messages as in "Enter special code" or "Enter unlocking code," or in some circumstances the device will probably display a message stating that it is locked. Whenever a valid code is entered, the mobile displays "Network unlocked” or “Network unlock successful”.


Handset suppliers have monetary incentives both to improve SIM lock security (which placates service providers and will allow exclusivity deals) as well as to weaken it (widening a handset's overall appeal to users that typically are not interested in the service provider that offers it). Moreover, making it too hard to unlock a smartphone could possibly make it significantly less appealing to mobile phone network service providers who have a legal responsibility to supply unlock codes for some handsets or in certain countries.

Unlocking Services:

Several companies offer a permanent unlocking service . This service calls for people who would like to unlock a mobile phone to supply their IMEI number to a service supplier and frequently they will also request the country and network the mobile is locked to, sometimes sent through email or entered on their web-site. The company will then provide (for a fee) an unlock code for the phone.

Unlocking Service Providers:

Regrettably there are a huge number of scammers organizations working in the cell-phone unlocking industry. Consequently it is prudent to ensure you locate a genuine supplier for this service. To aid with the search for a reputable service provider, we have supplied a listing beneath (and in no specific order) of a few genuine organisations currently offering such services.

Reputable Mobile Phone IMEI Unlocking Service Providers: