What is a Carrier-Lock?
From EjWiki
SIM lock: A sim-lock, network lock, Carrier Lock, IMEI-Lock or (master) SUBSIDY lock is actually a technical constraint built into GSM and CDMA smartphones by producers to be used by service providers to limit the use of these phones to particular countries and/or networks. This is contrary to a phone (retrospectively called SIM-free or unlocked) that doesn't enforce any SIM constraints.
Many cell phones can be unlocked to work with any GSM mobile phone network provider, although the phone may still display the original logos and may not support features of the new carrier. In addition to the locking, mobile phones can also have firmware that come with 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. Virtually all handsets can be unbranded by re-flashing another type of firmware version, an operation suited to advanced users only.
Unlocking Technology: A phone can be unlocked by entering a code provided by the network operator. Different mechanisms consist of software working on the device or a computer or laptop attached to the handset, hardware devices that link to the mobile or over-the-air by the service provider. Most of the time the unlock process is permanent. The code required to eliminate all locks from a smartphone is referred to as the master code, network code key, or multi-lock code. Generally if the phone is carrier locked it will generally display one of these messages: SIM network PIN blocked, Enter lock PIN.
Economics: The main reason to unlock a mobile phone is going to be able to use it with an alternative SIM card. Users may wish to keep on using their cellphone but with a different service provider or while traveling in foreign countries they may wish to connect to a international network by using a pre pay subscription.
Unlocking Services: A certain amount of companies provide a on-line phone unlocking service. This service calls for all those who need to unlock a phone to give their IMEI number to a service supplier and often they will also require the country and service provider the mobile phone is locked to, frequently sent via email or submitted on their website. The supplier then will provide (in return for a fee) an unlock code for the handset.
Unlocking Service Providers: Regrettably there are a huge number of dodgy sellers active in the smart-phone IMEI unlocking industry. Consequently it is recommended to ensure you locate a genuine provider for this service. To aid with your search for a reputable supplier, we have provided a list beneath (and in no particular order) of several genuine organizations currently offering such services.
Reputable Mobile Phone IMEI Unlocking Service Providers: Unlock BaseUnlock RiverCell UnlockerMobile UnlockedDoctorSIMUnlock.Zone
