Patent ID: 6954007
Filing Date: 2005-10-11
Classification: G07C

Abstract:
1. A method for controlling access to a secured location, in which an electronic key and a base station wirelessly exchange authentication data between one another in one of an active communication mode and a passive communication mode, comprising the steps of: transmitting a call signal by the base station to the electronic key at a beginning of an authentication procedure; responding to the call signal by the electronic key with a reply signal; implementing a safety procedure against a radio link extension in the active communication mode; analyzing the reply signal of the electronic key received by the base station to ascertain in which communication mode the reply signal has been received; transmitting a first selection instruction by the base station to the electronic key if the reply signal from the electronic key has been received in the active communication mode to cause the electronic key to conduct subsequent communication in the active communication mode; and transmitting a second selection instruction by the base station to the electronic key if the reply signal from the electronic key has been received in the passive communication mode to cause the electronic key to conduct subsequent communication in the passive communication mode.