On November 17, 1960, an Electronic Central Office at Morris, Ill., was formally dedicated. While this office was a Bell Telephone Laboratories experimental trial, it provided 24-hour-per-day commercial-grade service with no backup arrangements. The trial was of 14 1/2 months' duration and served the needs of 435 telephone customers. The majority of customers were also provided with one or more new services. Results of the trial furnished conclusive evidence as to the feasibility of electronic switching systems (ESS) and provided many answers needed in the design of future systems.