If the Phone shows Invalid Sim message means it locked to some Network,find out the Country,it's network it locked now ..then get the Unlock code from here Onlinegsmunlock
and Unlock it....Then You can use any GSM Sim card....
Pantech Pursuit Unlocking Instructions
Do not enter any wrong unlock
codes on your Pantech Pursuit mobile phones. If you enter over a certain
amount of wrong unlock codes on your Pantech Pursuit mobile phone, your
phone may get hard locked and sometimes become unusable.
1. Switch ON your Pantech Pursuit with its ORIGINAL
2. Type *#865625#.
3. A SIM Unlock Menu will appear, press OK.
4. Enter Unlock Code.
5. Re-enter Unlock Code.
6. Pantech Pursuit will display Unlock Process Complete. Press OK.
7. Your Pantech Pursuit is now unlocked.
: We mean, to use the sim card that was
originally given to you by your network/service provider along with the