Siemens Aktiengesellschaft

Franz Fahrenschon

Hans Thinschmidt

Alfred Meier

Ewald Dotzauer

Horst Jager

Heinz Huettl

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. The exemplary disclosre is particularly suited for the coupling of a telephone system with a separate telegraphy exchange system, whereby the selection possibilities of both systems can be used for telegraphy traffic.

Circuit arrangement for telephone exchange systems, especially

Error and condition messages are transmitted from unmanned telecommunication facilities to a central exchange having a maintenance control station. In order to safeguard this interference data alarm system against interferences in the secondary station and in the telephone network, the transmitting test unit is inserted in several lines used for normal telecommunications traffic, said lines leading to the maintenance control station. In order to transmit the messages, any one of these lines can be automatically selected for maintenance purposes by the transmitting test unit, whereupon a connection to the maintenance control station is automatically established and the necessary data sent to such station. A data dialog for error analysis is possible.

Circuit arrangement for an interference data alarm system in

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. This signal automatically effects a changeover in the calling station to the desired mode of message transmission, and this changeover is likewise acknowledged by a back signal. The changeover is reported to both subscriber stations participating in a call as an inquiry for acceptance of the desired message switching.

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Neuried, Germany

Franz Fahrenschon