Abstract: A modular telecommunication system comprises a plurality of switching blocks connected in parallel by interconnecting lines. Each of the switching blocks includes a multiplicity of line terminators each adapted to be connected to a data terminal. In each switching block there are provided (1) a central processing system for establishing communication links associated with a respective call, (2) a communications controller for controlling local data exchange between pairs of line terminators connected thereto across real channels, (3) a virtual channel controller for controlling remote data exchange across virtual channels to different switching blocks and (4) interface units arranged between the virtual channel controller and a respective one of the interconnecting lines.

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.