LOCK OR WINDOW OR DOOR FITTING

For simultaneous detection of the state of a locking element (12) and the state of the window or door, a lock (11) or fitting is provided, in which at least one coil (13) is arranged on the face plate (14) or on the strike plate, on the respective outer face thereof, wherein the coil (13) is arranged around the opening for the locking element (12). To determine the state of the door and the state of the bolt, an alternating voltage signal is applied to the coil (13), the impedance of the coil is determined, and said impedance is compared to predetermined values. To increase reliability, successive signals having different frequencies can be applied to the coil (13) and the impedance can be determined at said different frequencies and compared to predetermined values. Alternatively, a plurality of coils can be provided, namely a transmission coil (13a) and at least one receiving coil (13b), and the voltage induced in the receiving coil (13b) can be measured when an alternating voltage is supplied to the transmission coil (13a).