Abstract: A lock cylinder comprises a profile housing (1) with a cylinder core (9) disposed rotatably therein, and tumblers (15) which are controllable by a flat key. Disposed on the profile housing (1) is an information detector (37) which responds contactless to control information signals of a control circuit of the flat key, which is connected to an electronic control and power-supply circuit having at least some of its circuit components disposed separate from the lock cylinder. These circuit components are connected by a cable (43) and a plug connector (45) consisting of two plug parts (49, 51) complementary to one another. A first plug part (49) is mounted fixed on the profile housing (1), and the cable (43) bears a second, loose plug part (51) capable of placement on the first plug part (49).

Abstract: A method and an apparatus are provided for data transmission between a transceiver located in a drill hole and an above ground transceiver which are connected together by a two-wire line composed of an armoured, insulated copper core cable. The data are transmitted between the two transceivers via the two-wire line by successive, essential current-carrying time intervals. In the current-carrying time intervals, the portion of the transmitted energy is stored in the transceiver located in the drill hole, being stored therein for the current-free time intervals. The data are transmitted from the transceiver located in the drill hole to the transceiver disposed above ground by interrupting the current flow in the two-wire line or by short-circuiting the ends of the two-wire line, and are transmitted in the reverse direction by interrupt current feed of the two-wire line.