Yes, I am also talking about phone lock, not sim lock

Erm, if I am not mistaken phone lock works this way (at least for Nokia).

When you enter a sim card for the 1st time into a phone which is phone lock enabled, it will request for the security code. Once you have entered the code & successfully boot up the phone, it does not ask anymore until you insert a different sim card.

Please correct me if I am wrong...