The ESS, or electronic switching system, developed by the Bell System over a period of about 20 years, revolutionized communications in this country. This film footage (there is no sound), found in the AT&T archives, shows the grand opening on May 30, 1965, of the first implementation of an ESS switching office in the United States. These were the obvious benefits to the customer that the ESS made possible: three-way calling, call waiting, and speed dial. But the ESS streamlined internal functions as well-it paved the way for remote electronic monitoring and maintenance, providing modern diagnostic tools and requiring far fewer technicians to maintain the system. The implementation of ESS was tied to the development of the transistor. Though the transistor was first invented in the 1940s, a first test ESS office was online by 1958 in Morris, Illinois still retained some vacuum tube technology. Before the 1965 ESS installation, a private business, the Brown Engineering Company, in Cocoa Beach, Florida, tested an intermediate system in 1963. The commercial installation in Succasunna, New Jersey, was the very first of the No. 1 ESS. It initially served only 200 customers (of the town's 4,300) immediately after opening, but was designed to serve 65,000 phone lines, and switch 100,000 calls per hour. The second No. 1 ESS office was installed in Maryland in 1966. By 1974, there were 475 No. 1 ESS offices around the country, serving 5.6 million phone lines. The No. 1 ESS also became the basis for an iteration of AUTOVON, the military's own communications network. (AUTOVON was eventually replaced in the early '90s by DSN, the defense switched network.) The No. 1 ESS was superseded in 1976 by the invention of the #1AESS. The Succasunna central office's original No. 1 ESS depicted in this 1965 footage was finally taken out of service in 1992. Footage Courtesy of AT&T Archives and History Center, Warren, NJ