Roadmap to broadband ISDN

摘要

The two major emerging forms of ISDN (integrated services digital network), namely, narrowband and broadband (or B-ISDN), are contrasted. The authors note that although narrowband ISDN uses the technology of twisted pair loops, 64-Kb/s PCM (pulse-code modulation) circuit switches, and packet switches, B-ISDN will require fibre-optic links, digital cross connects, and optical switches; the probable network architecture of B-ISDN is asynchronous transfer mode (ATM) architecture with self-sorting mechanism, using asynchronous time-division (ATD) switching. Based on these needs, a four-step path from current service is outlined.