A network lock, known by many names including SIM lock, simlock, or subsidy lock, is a technology that wireless communications carriers use to prevent the mobile phones they sell from being used on another network. Cell phones can be locked to a particular country, network, or subscriber identity module card. A locked phone is typically sold to customers at a discounted price, since the carrier expects to earn income from the customer by providing wireless service to the phone. An unlocked phone able to use any service provider sim cards. Most of the mobile phones have only 5 chances to enter wrong unlock codes. You must get correct unlock and enter or your phone permanently locked with current service provider. So you can get unlock codes from your current network provider or any online unlocking service providers. Mobile-Unlocker.com is one of the trusted unlocking service provider for most of the GSM mobile phones world wide..