There are basically three main types of lock on mobile phones. They are: (1) Network Lock (2) Phone Lock or PIN lock (3) Restrict SIM lock. Network Lock restricts you from using other other network. For example the mobile phone from Australia Vodafone cannot be use with Vodafone New Zealand network. Do not be surprised that somtimes Kiwi cannot even use their Vodafone handset with the new Two Degrees Network as Vodafone New Zealand do lock up the handset they retails. Most of this lock can be unlock.
Caution: After unlock, you might lose all your data on the phone, you internet, MMS and GPS setting will be lost.
Phone Lock or PIN lock is whne the owner have forgotten the PIN or password on their mobile phone. In order to unlock this type of lock on your mobile phone, all pictures, database and data file. Unfortunately there might be a way around for not losing your data. However; there might be some exceptions (e.g. type of phone and unlock skill of the phone repair professional).
Restricted SIM Lock is the type of lock set up by owner or user of the mobile phone. This type of lock restrict the phone to recognise and allow phone started with only a specific SIM (not network dependent). This cab be unlocked but all phone data will be erased. This type of lock can be mistaken as "network lock"
