Donald J. Leonard

Donald J. Leonard
Donald J. Leonard
New York, NY, USA
Associated organizations
Bell Labs
Fields of study
IEEE Simon Ramo Medal


Donald J. Leonard was born on July 11, 1933 in New York, NY. He received the B.E.E. and M.E.E. degrees from New York University in 1956 and 1960, respectively.

Mr. Leonard joined Bell Laboratories in 1956. His early work involved the design and development of amplifiers, circuits and networks for digital transmission systems, telephone signaling systems, and the Telstar Satellite. While in the Transmission Technology Laboratory at Merrimack Valley, MA, he designed and developed lumped element, active and microwave components, amplifiers and filters, including the introduction of new synthesis and analysis techniques. As Director of the Telephone Laboratory at Indianapolis, IN, Mr. Leonard led the design and introduction of electronics, electret microphones and miniature plugs andjacks in telephones.

From 1977 to 1980, he was responsible for the development of all toll network and switching operations support systems. Subsequently he led the introduction of modern technology to improve the production of fiber, circuit packs and software as Vice President, Engineering for the Western Electric Co. Returning to Bell Labs as Vice President, Switching Systems in 1982, he led the R&D programs for all AT&T public switching systems. From 1991 until his retirement in 1994, he was responsible for developing processes and core technologies in the area of quality and software for all of AT&T business units and divisions.

Mr. Leonard spent most of his professional career in digital communications, making contributions to the design, development and architecture of digital switching, transmission and signaling systems.

He invented the method to imbed signaling information in the digital speech bit stream in the first digital carrier system. He envisioned common channel signaling (CCS), prototyped a system in 1958, and led the development and introduction of CCS into the network. He made significant contributions to the network architecture that positioned the 800 and calling card data bases in the CCS network. Recognizing the need to have definable, distributed, modular software and hardware architectures in switching systems, he worked and interacted with his managers to make it happen. He also instituted quality and product management processes for all switching products. Under his direction, 5ESS, a small local switch in 1982, was evolved to become a metropolitan switch, a toll switch, an ISDN switch, an operator services switch and a gateway switch--the premier switch being used worldwide.

He is a Senior Member of the IEEE, a member of the New York Academy of Sciences, and of Eta Kappa Nu and Tau Beta Pi. He holds two patents and has authored numerous technical papers. In 1984 he was awarded Honorary Doctor of Engineering from Midwest College of Engineering.

He and his wife, Jeanne, reside in Chatham, NJ and have seven grown children. He presently devotes his time and energy volunteering as an EMT for the Chatham Emergency Squad, working at Corpus Christi Church, and as a member of the Board of Trustees and Chair of the Education and Faculty Affairs Committee at Monmouth University. He enjoys his children and grandchildren, exercising and ice skating, as well as playing bridge, hiking, walking and traveling with his wife.