Abstract: An expansion network for increasing the number of subscriber terminations at a passive optical bus system comprising optical mixers is disclosed. The mixers are arranged in groups and the optical transmitters individually provided per subscriber are connected to the light receivers likewise individually provided per subscriber, being connected thereto in the manner of a mesh network via respectively only one of the mixers so that the attenuation of only one mixer is inserted into the optical path.

Abstract: For the purpose of expanding the connection capacities of optical mixers in order to form a large network, series connections of such optical mixers are provided. In such networks, such series connections are formed of optical mixers which produce signal transmission paths which are identical to one another. No different signal transmission paths are present in the network overall.

Abstract: Given a bus system comprising an optical waveguide, an electro-optical transmitter, and an opto-electrical receiver, the transmitter is constructed such that the light power coupled into the light waveguide and dependent on the information signal to be transmitted is variable in digital steps. The receiver is comprised of DC-coupled amplifiers without gain control. It contains a preliminary stage for generating a useful signal from the light signal, and has a first comparator stage for generating the information signal from the useful signal. The receiver also includes a second comparator stage to which a reference voltage variable in digital stages is supplied and which samples the level of the useful signal emitted by the preliminary stage. The second comparator stage emits a collision signal when the useful signal moves the reference voltage upwardly and thus indicates that at least two transmitters are coupling light into the optical waveguide.

Abstract: An optical passive bus control system includes an access coordinator and control unit which is connected to the passive network in the same manner as other connected devices of the network. The access coordinator control means is located spatially close to the optical mixer, over connecting light wave guides which are as short as possible. The access coordinator and control unit contains a collision recognition device for recognizing an access collision, and includes means for implementing an asynchronous access operating mode in response to a collision recognition. A switch means is provided for emitting a signal to the bus, signifying a change to a synchronous operating mode in which no access collisions can occur.

Abstract: A test facility is disclosed for error diagnosis in multicomputer systems, particularly in multi-microcomputer systems in which signal voltages on the system bus in the error diagnosis are made perceptible as optical signals by display devices directly controlled by the signal voltages. A decoupling device is provided for connecting an evaluation/control logic to the system bus and an address/data information display device, an access signal display device, a bus control signal display device and an interrupt signal display device are provided. At least one comparator module is provided whose first group of signal inputs receives a binary information corresponding to a selection address, adjustable by means of a selection switch, and whose second group of signal inputs receive information concerning the address line of the system bus.

Abstract: For extension of data traffic within a telephone exchange system to separate data exchange systems, special connecting sets, which are provided for data traffic within the telephone system, are fixedly connected via special facilities with subscriber exchange lines of the separate data exchange system. The special facility thereby takes over the function of the conversion from line and data signals from one system into the other and vice versa. For securing of telephone subscriber selection criteria in the case of arriving traffic from the data exchange system, arriving connection requests are only acknowledged if the selection digits which are necessary for the build-up of the telephone connection which conducts them further have arrived in the special facility. Besides this, the telephone ring signal for the desired telephone station is suppressed.

Abstract: Apparatus is described for telecommunication facilities having transmission paths capable of accommodating different types of message switching, e.g., voice communications and data communications. A changeover device in the subscriber stations in the system switches between the two modes of communication by means of a mode selector switch for causing manual or automatic switching between the two forms of communication. After switching through a call carried by a given connector set, a signal is automatically sent from the connector set to the called subscriber station. This signal causes an automatic changeover from the form of message communication being used to a second form, e.g., from voice to data. Upon completion of the changeover in the called subscriber station, acknowledgement of this fact is made by sending a back signal from the called station. Responsive to this acknowledgement, a signal is likewise sent to the calling subscriber station.