Abstract: A method is specified for operating a communication and/or control system via a line network equipped with socket outlets, in which for the supply of a standardized supply voltage at least one transmission line is connected to at least one socket outlet, which line is connected with an apparatus via a plug connected into the socket outlet and on which apparatus-specific signals are transmitted. The transmission takes place according to one of at least two selectable transmission protocols, whereby one of the two transmission protocols is selected according to the type of device which is connected.

Abstract: In a method for operating a digital data transmission network, and in a digital data transmission network operating according to the method, in an initial part of a transmission event between a control unit and at least one user unit in the network, a first data block containing data and a second data block containing data are transmitted from the control unit to the user unit. In the control unit, a first reference number is prescribed as a first transmission parameter in the first data block, which identifies a number of bit places provided for subsequent data transmission of the data contained in the first block from the user unit in a first useful channel. The control unit also prescribes a second reference number as a second transmission parameter in the second data block, identifying a number of bit places for subsequent data transmission of the data contained in the second block from the user unit in a second useful channel.

Abstract: A procedure for the transmission of digital data in a control/monitoring system of a building in which a number of room-specific nodes, one of which operates as a central node, are interconnected by cables and used as control units, which form a loop. Data flows in the system in the form of packets including the fields required for data transmission in the system, as well as fields for commands and corresponding data transfer required by the system. The fields for commands having leading and trailing flags indicating the status of such fields. When a receiver releases a field for commands for a following user, this is done by means of a status bit acting as a trailing flag and being the last in the time scale. This status bit is then transferred by the central node so that it becomes a status bit preceding the released field and acting as a leading flag. This method of handling the status information provided by the flags reduces the need for data buffering at the nodes.

Abstract: A method and apparatus for measuring the tension of a thin, plane membrane (1). In accordance with the method, a burst of a membrane wave (2) is generated by a transducer element (3) e.g. a loudspeaker (3). The velocity of the membrane wave (2) is measured. The velocity measurement value of the membrane wave (2) is squared and multiplied by the basis weight of the membrane (1) in order to determine the tension. According to the invention, a light beam (10) is generated by at least one light emitting element (5), each light beam (10) is projected with help of projecting members (6 or 14, 15, 17) onto the membrane (1) in order to generate a light spot (4 or 19), the light spot (4 or 19) vibrating on the membrane (1) is converted into an electrical signal dependent on the position of the light spot (19) by means of at least one detector element (8 or 18 ) in order to determine the membrane wave (2) and the signal is processed in a processor (9) in order to determine the velocity of the membrane wave (2).