Abstract: This paper describes the architecture and initial implementation of an experimental telephone system developed by the Computer Science Laboratory at the Xerox Palo Alto Research Center (PARC CSL). A specially designed processor (Etherphone) connects to a telephone instrument and transmits digitized voice, signalling, and supervisory information in discrete packets over the Ethernet local area network. When used by itself, an Etherphone provides the functions of a conventional telephone, but it comes into its own when combined with the capabilities of a nearby office workstation, a voice file service, and other shared services such as databases. Most of the work so far has gone into the basic provisions for voice switching and transmission. Today the system supports ordinary telephone calls and simple voice message services. We will expand these functions as we explore the integration of voice with our experimental office systems.

Lawrence C. Stewart received the S. B. degree from the Massachusetts Institute of Technology, Cambridge MA, in 1976 and the M.S. and Ph.D. degrees from Stanford University, Stanford, CA, in 1977 and 1981, respectively, all in electrical engineering.

Since 1977, he has been with the Xerox Palo Alto Research Center, Palo Alto, CA, joining the Computer Science Laboratory there in 1981. His current interests are in data compression, voice communications, computer networks, and computer systems.