Abstract: A digital data telecommunications system comprises a central switching system and a plurality of line terminators each connecting the switching system to a pair of incoming and outgoing lines and each designed to convert serial data transmitted along the incoming and outgoing lines into formatted message characters for transfer through the switching system, and vice-versa. Control data stored in a connection memory for the duration of a call enable the switching system to interconnect sequentially each calling line terminator with the respective called line terminator in a time multiplex mode for transmitting one message character at a time. An arrangement for establishing multi-address connections includes an additional line terminator connected to receive a character of a multi-address message from a calling line terminator across the switching system. A distributing data bus connects this line terminator in parallel to all line terminators entitled to receive a multi-address message.

Abstract: A modular telecommunication system comprises a plurality of switching blocks and a plurality of inter-connecting lines for interconnecting the switching blocks. Each of the switching blocks includes a multiplicity of line terminators each adapted to be connected to a respective data terminal. A communications controller is provided in each switching block for controlling local data exchange between pairs of line terminators connected thereto across real channels. A virtual channel controller is connected to the communications controller and controls remote data exchange across interconnecting lines via virtual channels between a locally associated data terminal and a data terminal associated with a different switching block. A central processing system is connected to the virtual channel controller and controls setting up switching operations within both the virtual channel controller and the communications controller.

Abstract: A modular telecommunication system comprises switching blocks interconnected by bus-oriented interconnecting lines. Each switching block includes line terminators each adapted to be connected to a respective data terminal and control means for controlling local data exchange between line terminators directly connected thereto and remote data exchange from local line terminators to a data terminal associated with a different switching block. The interconnecting lines include a plurality of individually controlled interlink buses, which are coupled to each switching block by a separate interlink-bus interface unit and a short distance transmission line. Data transfer across an interlink bus is performed under control of an interlink-bus controller associated with each bus, by scanning the interlink-bus interface units. Data characters are transmitted in time-multiplex mode together with address information of the receiving switching block for selecting the receiving interlink-bus interface unit.

Abstract: A modular telecommunication system comprises a plurality of switching blocks and a plurality of inter-connecting lines for interconnecting the switching blocks. Each of the switching blocks includes a multiplicity of line terminators each adapted to be connected to a respective data terminal. A communications controller is provided in each switching block for controlling local data exchange between pairs of line terminators connected thereto across real channels. A virtual channel controller is connected to the communications controller and controls remote data exchange across virtual channels to different switching blocks. Interface units are arranged between the virtual channel controller and a respective one of the inter-connecting lines for providing remote data exchange between data terminals each associated with a different switching block.