Abstract: In a communications system with a plurality of subscriber stations independent of each other, where each subscriber station can access a joint duplex transmission channel according to a multiple access method, the probability of simultaneous attempts to get access becomes very image, and thereby the probability of signal destruction is particularly increased. In order to avoid a blockage of the service channel each subscriber station occupies the duplex transmission channel with a short access signal for initiating a transmission starting from the subscriber station. The subscriber station characterized by the position in time and/or the information contents of the short access signal is thereupon invited by the central base station to emit an access signal to join practical access to the communication exchange.

Abstract: A method for transmitting digitally coded analog signals which are combined in coding blocks in a digital packet multiplex system permits transmission of coding blocks having a length which does not correspond to the normal useful packet length. In such an instance, packets having a different content are generated and information identifying such packets is transmitted to the receive side of the system in the form of a designated number of bits in the existing available transmission capacity of the beginning of the packet, so that the beginnings of the coding block can be recognized at the receive side.

Abstract: The invention relates to a method for measuring impulse periods, faults locations and attenuations in cables and light wave conductors. The object is to provide a particularly simple method which can be realized with little expense. The solution basically consists in the fact that each measuring impulse releases a saw-tooth generator, that the time value of the voltage delivered from the saw-tooth generator is compared with an adjustable direct current voltage and serves to open a gate circuit at specific times, that the reflected impulse is compared by a second comparator with a second direct current voltage and that the thus separated signals are led to the gate circuit and displayed by an indicator. The invention will primarily be used in locating faults in light wave conductors under difficult conditions on the construction site.

Abstract: The invention relates to a method for measuring impulse periods, faults locations and attenuations in cables and light wave conductors. The object is to provide a particularly simple method which can be realized with little expense. The solution basically consists in the fact that each measuring impulse releases a saw-tooth generator, that the time value of the voltage delivered from the saw-tooth generator is compared with an adjustable direct current voltage and serves to open a gate circuit at specific times, that the reflected impulse is compared by a second comparator with a second direct current voltage and that the thus separated signals are led to the gate circuit and displayed by an indicator. The invention will primarily be used in locating faults in light wave conductors under difficult conditions on the construction site.

Abstract: The invention relates to a circuit for deriving output of signals and output counter cycle signals from a one-sided input signal.The circuit contains two transistors coupled to at least one current reflecting circuit. The two outputs of the current reflecting circuit are connected either with the emitters or the collectors of two transistors, whereby one connecting line at least one resistor is disposed. The interconnected bases of each of the two transistors are connected to an adjustable direct-current source. The equal electrodes of the two transistors which are not connected with the current reflection circuit form the signal output and the signal counter cycle output.

Abstract: A drive circuit for a step motor, where the stator windings of the step motor are in each case connected in series to a diode and where a capacitor is connected in parallel to the series of diode and winding. The above element is provided with power from a d.c. source via a thyristor switch. The circuit provides that upon firing of a thyristor the previously current conducting thyristor is switched off. Thus step motors can reliably be operated, where up to the switching to another winding still a holding current is to flow.