Unlocking means remove the Network lock from your phone.Your phone says Invalid sim means that your phone is locked to particular Network.To solve this problem You need to unlock your phone.You can unlock your phone easily using unlock code.Unlock code is the best and safest way to unlock phone.You can get the unlock code for your phone from your Network service provider or any third party online vendors like http://www.simpleunlocking.com/supported-phones/rs16wp7/ here you need to specify your phone model,country,current Network name,IMEI number of your phone.Then they deliver unlock code to you through mail with unlocking instructions.Using this you can unlock your phone easily.
sahana, September 2013
