What is a imei lock

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SIM lock:

A SIM-Lock, Network Lock, Carrier-Lock, imei-lock or (Master) subsidy lock is really a technical limitation built into CDMA and GSM mobiles by manufacturers for use by carrier networks to limit the use of these phones to specific countries and/or networks. This is in comparison with a cell phone (retrospectively called SIM-free or unlocked) that does not impose any SIM constraints.

The vast majority of phones can be unlocked to operate with any GSM mobile phone network provider, but the phone might still show the original branding and may not support popular features of the new service provider. Apart from the locking, phones might also have firmware attached to them which is specific to the mobile phone network provider. This firmware is installed through the service provider which is separate from the locking mechanism. The majority of handsets can be unbranded by re-flashing a different firmware variation, a process suited to advanced users only.

Unlocking Technology:

Typically, a locked handset will show a message if a restricted SIM is used, requesting the unlock code. On new phone models working on Android operating system software, the cellphone will show a message stating “SIM network unlock PIN” or “Enter Network Lock Control Key” if it's network locked. Windows phones will display the message, “This SIM card can only be used on specific networks. Contact your customer service center for the unlock code”. Other models might show alternative messages like "Enter special code" or "Enter unlocking code," or in some circumstances the handset will simply present a message saying that it is locked. As soon as a valid code is keyed in, the mobile phone will display "Network unlocked” or “Network unlock successful”.


The primary reason to unlock a device is going to be able to utilize it with another type of SIM card. Users may need to continue using their mobile phone but with a new service provider or if traveling in another country they might want to connect to a international network by using a pay as you go subscription.

Unlocking Services:

A number of companies provide a remote phone unlocking service . This service needs all those who wish to unlock a phone to give their IMEI number to a service supplier and quite often they will also ask for the country and cellular network the mobile phone handset is locked to, often sent through email or submitted on their web site. The supplier then will supply (at a cost to you) a unlock code for the mobile phone. For a few manufacturers for example Nokia and Samsung several services also deliver unique remote-unlocking software with instructions, where a cable connection is required to remove the SIM lock at home. Such vendors may email the unlocking code or software that will remotely unlock the unit. The price for unlocking a telephone can differ depending on the network it's locked to and the phone model itself, as each unlock code is unique to each unique handset.

Unlocking Service Providers:

Regrettably there are lots of scammers sellers active in the smartphone unlocking industry. Consequently it is prudent to make sure you use a honest supplier for this service. To aid with a search for a reputable company, we've provided an inventory below (and in no particular order) of several genuine organisations currently offering such services.

Reputable Mobile Phone IMEI Unlocking Service Providers: