An optical ISDN S-bus extension in a private multimedia network

摘要

The communication network specified by CCiTT for the basic access to the S/T reference point of the ISDN covers distances up to several hundreds of meters in the passive bus configuration, or up to one kilometre for point to point connection. But for many applications much longer distances must be covered. Most PABX's currently available can only meet the requirements of long lines by using analog transmission techniques.The interface described in this paper offers the possibility to extend the S-bus of the public ISDN on 3 of the 24 channels of a multiplexer through singlemode or multimode fibres, and it performs a plesiochronous type of transmission.The ISDN frame at 192 KBit/s of the S-bus on 4 wires is transmitted completely transparently on 3 channels of the multiplexer. At the other end, all the signals as well as the power supply are restituted.The interface is, according to CCITT recommendations, so that all current and future basic access developments of the S-bus in the European public networks will be fulfilled.By replacing the optoelectronic interface of the multiplexer with an electric G703 interface, the multiplexer has access to a higher multiplex layer at 8 MBit/s (DMX-8).