Abstract: An activity detector for the recording and transmission of activity data of an animal to a reader unit is described. The activity detector comprises a movement sensor, a recording and transmission unit connected with the movement sensor, and an energy source with an energy store supplying the recording and transmission unit. The activity detector furthermore includes an electrical generator converting kinetic energy into electrical energy, which is connected via a rectifier with the electrical energy store.

Abstract: A security system includes a base station and at least one transponder. A data dialogue takes place between the base station and the transponder in which the transponder sends back data to the base station on a carrier frequency in the RF (radio frequency) range. The transponder comprises a first transmitter and a second transmitter for data transmission to the base station and/or to a read/write device. The second transmitter sends on an electromagnetic carrier frequency in the LF (low frequency) range, and an audible carrier frequency in the ultrasonic range or an optical carrier frequency in the infrared range.

Abstract: The invention is a process to transmit data between a read/write device and a transponder. The data is transmitted by a change in field strength of an electromagnetic or magnetic field, and the times between sequential field strength changes are evaluated. At least at the beginning of data transmission, the systematic time deviation from the setpoint is determined that arises upon a switching threshold in the field strength changes. A correction value is derived, and the subsequently determined times are changed by the correction value. This correction allows for a greater amount of data to be transferred from the read/write device to the transponder.

Abstract: The invention relates to a device and process for data transmission. The data is transmitted by changes in the field strength of an electromagnetic or magnetic field, and then the times between at least two sequential field strength changes are evaluated. A frequency serving as the time base for evaluating the times between the field strength changes is calibrated at least at the beginning of data transmission so that it has a set relationship to the cycle duration of the field strength changes.

Abstract: In a circuit for supplying power to a subscriber telephone device connected to a central office via a two-wire line, which circuit includes a main power supply at the central office and a switching unit at the telephone device actuatable to place the device in operation and to connect an electrical load in circuit across the line, there are additionally provided an auxiliary power supply disposed at the central office and connected across the line when the telephone device is not in operation, and a circuit connected for selectively connecting the main power supply to the line when the telephone device is in operation.

Abstract: In a circuit for supplying operating power from a power supply at a central office to a telephone device at a subscriber location via a two-wire line, and including a switching unit at the subscriber location actuatable to connect the telephone device to the power supply to place the device into operation, there are further provided a first switching device connected between the power supply and the line for controlling the supply of power to the line, and a second switching device connected between the line and the telephone device for controlling the delivery of power from the line to the telephone device, with each switching device being connected to respond to the traversing of a threshold by a parameter of the power from the power supply.