A computer program product has a check routine and an active part. When the computer program product is called, a computer, while processing the check routine, initiates a transmitter to send a launch signal. A transponder receives this signal, checks whether a time-dependent and/or usage-dependent transmission...http://www.google.com/patents/US7555654?utm_source=gb-gplus-sharePatent US7555654 - Apparatus, transponder, computer program product and method for enabling an active part of a computer program
