Abstract: Two-way time division multiplex (TDM) links interlace a plurality of digital exchanges such that the possibility of path selection is available for transferring information between two of the exchanges. Instead of conventionally selecting a path for each ordered call set up, the exchanges coact such that there is generally established a one-way TDM loop between all exchanges, this loop being established by parts of said links. For calls between arbitrary exchanges the loop only is used. The operational ability of the links is monitored continuously before and after establishment of the loop. It is possible to reconfigurate the loop during calls in progress for achieving improved information transfer quality.

Abstract: This invention provides a high-speed queue sequencer which may be employed as a component of a link switch or hub switch in a burst-switching communications system. When so employed, transmission speeds for integrated voice and data services over communications links between switches may be equivalent to the T1 rate or higher. A burst is a plurality of bytes which represents, for example, a block of data or a spurt of voice energy sensed by silence/voice detectors located at voice ports.

Abstract: A pair of integrated circuits are described which provide a digital link between a branch exchange and a voice and data channel using an ordinary twisted pair. The downlink circuit permits coupling to a serial asynchronous port of different protocol than that used over the link and for instance, this port may be coupled to a keyboard, display or data terminal.