GB1493622A - Time division multiplex data exchanges - Google Patents

Abstract

1493622 Data transmission; multiplex exchanges GENERAL ELECTRIC CO Ltd 18 Feb 1975 [18 Feb 1974] 7301/74 Heading H4P A data multiplex exchange has a plurality of grouped input subscribers, individual groups 10 being unirate, multiplexed at 1 over paths 11 to respective circuits 2 which arrange/rearrange time slot occupancy and performing further multiplexing of streams on to highway 5, with a selector 3 providing at 19À2 b/s a signal path and sub address memory controlling timing selection of the various channels, the number of streams being dependent on input bit rate at 10 and include idle channels. Non idle channels have all zeros inserted when not in use at any time. Highways 5 are applied to a cross point space switch controlled by a cyclic store of cross point addresses, one for each channel, which are written in under control of 8 and processor 9, there being 32 inputs with 32 outputs to highway 7. For a particular input highway 5, each channel is transmitted through a particular one of the 32 cross points for the duration of transmission; each cross point may be used several times within a 320 channel frame so that several channels may have the same path through the space switch. An output highway 7 therefore carries at 1À92 MHz a selection of channels from different input highways 5. An output circuit 12 corresponding to 2, one for each highway 7, comprises an output store 14, sub address memory 14 effecting the first stage of demultiplexing to produce streams of 60 Kb/s and may switch time slots on 7 to any selected slot on 19 before application to final demultiplexer 15. The various streams are then distributed amongst 320 subscribers. The arrangements are described in greater detail in relation to Figs. 2 and 3 (not shown).