Multiplex concept for a digital optical subscriber network

摘要

Multiplex concept for a digital optical subscriber network, comprising a broadband communications central unit and subscriber connection devices. In the broadband communications central unit, the input bit flows O1 originating from the distributive services (15 TV channels) and the outgoing communications services (BiF), in each case with high bit rates, are each converted according to the invention, after passing through a plesiochronous standard multiplexer (MUX C), into a respective standard bit flow O1<+> with the central clock of the broadband communications central unit. These, for example, 16 standard bit flows are fed to a subscriber-individual distribution exchange (TV-VSt) in which the subscriber can select three standard bit flows simultaneously via a backward channel standardised with the incoming communications services (BiF, ISDN). In one of the three selectable standard bit flows, the input bit flow O2 leaving the low bit-rate communications services (ISDN) is inserted, following preceding frame identification, in the position of an unoccupied additional capacity ( DELTA O)2. The three selectable standard bit flows are present in a synchronous multiplexer (MUX A) and, in conjunction with a fourth standard bit flow with distributive services of low bit rate O3 and an additional capacity, produce the bit flow O4 (Fig. 1). In the subscriber connection device, the input bit flows O1, O2, and O3 are retrieved in corresponding reversal from the incoming bit flow O4 in a synchronous demultiplexer (DEMUX A), three standard demultiplexers (DEMUX C) connected downstream, a special plesiochronous demultiplexer (DEMUX C) and a special plesiochronous demultiplexer (DEMUX C'). The bit flows leaving the subscriber for high bit-rate (BiF) and low bit-rate (ISDN) communications services and the control signals (S1-S3) for selection of the standard bit flows are combined in a standard multiplexer and transmitted in wavelength division multiplexing to the broadband communications central unit. <IMAGE>