Issue No.06 - June (1979 vol.12)
J.M. Kasson , Rolm Corporation
The private branch exchange, employing pulse-code modulation and computer-controlled time-division multiplexing, is an increasingly popular tool for enhancing the flexibility and reducing the cost of business telephone operations.
J.M. Kasson, "The Rolm Computerized Branch Exchange: An Advanced Digital PBX", Computer, vol.12, no. 6, pp. 24-31, June 1979, doi:10.1109/MC.1979.1658776