Abstract: An incoming interface for a cross-connect system comprises a first selector for coupling a signal from an incoming link to an STS-1 receive processor or to the first input of a second selector. A demapping circuit is connected to the STS-1 receive processor for extracting a DS3 payload signal and supplying it to the second input of the second selector. A DS3 receive processor is connected to the output of the second selector for processing a DS3 signal. A third selector has a first input connected to the STS-1 receive processor and a second input connected to the DS3 receive processor for establishing a connection between its first or second input to a cross-connect switch. An outgoing interface for the cross-connect system includes a DS3 transmit processor for processing a DS3 signal from the cross-connect switch. A third selector connects the output of DS3 transmit processor to a mapping circuit or one input of a sixth selector.

Abstract: A digital loop system with a distributed architecture that provides telephone services with high reliability and quality and is cost-effective to install. The system is central office powered and uses a trunk unit interface to interface with a wide range of mechanical and electronic switches. The trunk unit interface connects to remote terminals via digital transmission lines. The remote terminals drive a large number of subscriber circuits through short subscriber loops. The distributed digital loop system employs sealed and environmentally hardened packaging for flexible outdoor installation. The electronic circuitry used by the remote terminals is divided into modules for flexible, incremental deployment of the system.

Abstract: A large capacity switch architecture is disclosed, which uses a novel "split" interface. The first part of the split interface is called a Peripheral Shelf Link Interface Unit (PSLI) and is mounted remotely from the central control. The second part is called Peripheral Interface Unit (PIU) and is mounted locally to the central control. The PSLI and the PIU are available as a copper or fiber optics dedicated unit. By selecting the appropriate matching pairs, communication can be had over a copper or fiber optics transport medium.