Experimental single-chip PABX

Experimental VLSI techniques and an architectural concept are described which permit the realization of an experimental single-chip private automatic branch exchange (PABX) for switching voice and data. Analysis indicates that up to 40 telephones and 40 data terminals could be interconnected with a single chip. The architecture makes it possible to interconnect multiple PABX chips to form a larger system. The single-chip concept is made possible by distributed switching near the subscriber, digital interface, a new `orthogonal' RAM, and a low-power line-driving technique, all of which are included in this investigation.