Abstract: In a communication network for transferring signals, e.g. according to the SONET or SDH standards, interconnecting node devices are provided consisting of parallel processing modules (9-T, 9-R). A plurality of processing modules with first and second interfaces rearrange/insert/extract tributary signals and configurable multiplexing/de-multiplexing components enable each processing module to access any portion of an arbitrarily preselected tributary signal. In a SONET/SDH system, signals between SONET/SDH frames are rearranged on incoming (20) and outgoing (26) main lines=Digital Cross-Connect, or tributary signals are transferred between frames and local lines (16-i-T, 16-i-R)=Add/Drop Function.

Abstract: In a local area communication system comprising token rings (11) with synchronous bandwidth managers SBM (15) for issuing priority tokens for quasi-synchronous frames at regular intervals, the rings are interconnected by a time division muliplex PBX unit (21) via their SMB units. Buffers are provided in each SBM for synchronous information blocks transferred from and to the ring, and the TDM control (31) can independently access these buffers for TDM switching of the individual bytes of said information blocks. Besides this PBX interconnection for synchronous information or voice, the rings are also interconnected by a backbone bus or ring for transfer of asynchronous data between rings. A special slot rearrangement procedure is provided to improve the filling of time slots in the quasi-synchronous frames that are no longer used after release of a connection, to allow for adapting the frame length (number of issued slots) to the number of existing connections.