The HHI service integrated optical broadband communications system-results of a long time operation and review

The communications system is a service integrated network combining a digital net and an analog net, both furnishing the services telephone, data, videophone, stereo broadcasting and television. The digital system consists of different subscriber loops at 10 Mbit/s, 17 Mbit/s, 140 Mbit/s and 280 Mbit/s transmission rate (according to the PCM hierarchy), which are linked to each other via a local trunk (280 Mbit/s) and a long distance trunk (560 Mbit/s). A gateway to the analog net is installed. While the analog net is a traditional star type network with central exchange, totally distributed control is employed in the digital net. The communications system makes use of digital as well as analog optical broadband transmission, where the amount of glass fibers in the whole system comes up to 150 km, employing 36 regenerators at variable repeater distances (100 m up to 4.6 km).