An apparatus and method for locking and unlocking mobile telecommunications handsets or other devices is disclosed. Each handset is unactivated at the time of purchase. Other than emergency calls, or account activation, no calls can be made using the handset unless it has been unlocked. The handset is...http://www.google.de/patents/US5864757?utm_source=gb-gplus-sharePatent US5864757 - Methods and apparatus for locking communications devices
