Patent ID: 7023321
Filing Date: 2006-04-04
Classification: G07C

Abstract:
1. A method for transmitting and receiving signals between at least one first transmitting and receiving device and at least one further transmitting and receiving device, in particular for unlocking and/or locking a vehicle, a) monitoring with the first transmitting and receiving device, via a first communication path of a given frequency, for the presence of the second transmitting and receiving device, b) transmitting a request signal from the first transmitting and receiving device via the first communication path on detection of the second transmitting and receiving device, c) setting up a second communication path of a lower frequency than the frequency of the first communication path for a predetermined time interval between the first and the second transmitting and receiving devices as a function of the request signal, and d) measuring the reception power level in the second transmitting and receiving device by means of a measurement device.