Siemens Aktiengesellschaft

Siemens Aktiengesell Schaft

Norbert Wingerath

Robert Lechner

Hans-Werner Rudolf

Harald Stader

Nigel P Dyer

Pierre Albouy

Virgilio Mosca

Robert K Galpin

Christopher C Priest

Antonio Nicastro

Ramatchandirane Nadaradjane

Marcello Manca

Robert Le Gougnec

Thyristors utilized as protective elements receive trigger current by way of a respective semiconductor switch having a control electrode thereof coupled to a supply battery. The supply battery thus need only supply the sum of control currents for respective semiconductor switches whereas the current required by the protective thyristors is provided by the interfering source, for example, by a stroke of lightning.

Circuit arrangement for protecting electronic interface circuit of

A circuit for subscriber line interface circuits in a digital time-division multiplex communication switching center is disclosed. In the case of reception of the same information on the same time slot allocation via a number of subscriber line interface circuits, a transmit time slot as well as a receive time slot is alloted, but access of the transmit driver stages of the subscriber line interface circuits to the bus conductors leading to the switching center is prevented in order to avoid damaging interacting final stages in the transmit driver stages of the subscriber line interface circuits.

Circuit for subscriber line interface circuits in a digital

A digital interface between at least two subscriber line interface circuits and a processing unit is described. The interface is configured in the form of a parallel interface. The level of an input/output register and of a control register is allocated, as needed, to the connections of the processing unit. These connections can be operated selectively as inputs or outputs. They can also be operated in two modes, depending upon which type of subscriber line interface circuit (SLIC) is connected. The connections of the last-mentioned units are partially operable as inputs or outputs and partially operable only as inputs but in the input case, selectively for various types of input signals.

Digital interface between at least two subscriber line interface

A digital interface of an integrated subscriber line interface circuit is provided. The interface serves for the connection of a signal processor unit. Individual connections are used as signal inputs in signal entry operation of the interface, and as signal outputs in signal transmission operation. Other connections are used as signal inputs in both operating mode, but receive different signals in each operating mode. One group of connections includes two registers with respective associated decoders to enable switching from one to the other, so that the number of operating instructions that can be represented by means of binary signal value combinations applied to the connections is doubled.

Digital interface of an integrated subscriber line interface circuit

In a subscriber termination module for coupling a plurality of subscriber termination lines of a digital time multiplex telecommunications network, lines coupling a central portion and local portions individually allocated to at least one subscriber termination line are selectably utilized for the transmission of status setting information to the local portions for setting different operating conditions and for serial transmission, that is, successive transmission of information to be supplied to the individual local portions as well as for simultaneous information transmission from the local portions to the central portion, that is, parallel information transmission.

Method for the operation of an interface circuit between a central

The invention relates to a circuit arrangement for the indication of loop closure during the ringing condition for a subscriber circuit which is connected to the exchange of a digital time multiplex telephone system by way of a subscriber termination circuit comprising a subscriber line interface circuit which, in part, provides the ringing supply and signalling, and a signal processing unit which, in part, provides for analog to digital conversion and digital to analog conversion as well as for filtering. The circuit arrangement includes a changeover switch, by way of which, a signal representative of the subscriber termination line current is applied to the signal processing unit during the ringing condition, in place of the speech signal present during the speech condition. This voltage signal is subjected to analog to digital conversion and filtering as for the speech signal at other times except that the high-pass filtering otherwise employed is avoided, and in that the resulting digital signal is further summed over at least one period of the ringing signal frequency. The sum signal is compared with a reference value which provides a loop closure signal when the reference value is exceeded by the sum signal.

Growing community of inventors

Munich, Germany

Norbert Wingerath