T-Mobile Network SIM Card Lock Default Code [SOLVED]
If you have just got a new SIM card from T-mobile network and you have tried setting up SIM card lock then this code is the default and will work for you.
Default T-Mobile Network SIM card lock code is: 1210
This code allows you to change the sim card lock code so if you loose your phone and someone tries to power your phone on or put your SIM card in another phone it will ask for this code. It prevents people from running up your phone bill etc. Very useful!