Direct distance dialing

Direct distance dialing (DDD) is a telecommunication service feature in North America by which a caller may, without operator assistance, call any other user outside the local calling area. Direct dialing by subscribers typically requires extra digits to be dialed as prefixes to the directory telephone number of the destination. International Direct Distance Dialing (IDDD) extends the system beyond the geographic boundaries of the North American Numbering Plan (NANP). The first direct-dialed long-distance telephone calls were possible in the New Jersey communities of Englewood and Teaneck. Customers of the ENglewood 3, ENglewood 4 and TEaneck 7 exchanges, who could already dial telephone numbers in the New York City area, could place calls to eleven major cities across the United States by dialing the three-digit area code and the seven-digit directory number. Local telephone numbers still consisted of the first two letters of the central office name and five digits. On November 10, 1951, Englewood mayor M. Leslie Denning made the first customer-dialed long-distance call, to Mayor Frank Osborne of Alameda, California. The destinations, and their area codes, equipped with a long-distance toll-switch at that time were: 617: Boston, Massachusetts 312: Chicago, Illinois 216: Cleveland, Ohio 313: Detroit, Michigan 414: Milwaukee, Wisconsin 415: Oakland, California 215: Philadelphia, Pennsylvania 412: Pittsburgh, Pennsylvania 401: Providence, Rhode Island 916: Sacramento, California 318: San Francisco, California Other areas could not yet be included in DDD as they did not have the necessary toll switching equipment, or because they still did not use a seven-digit local numbering plan. Montreal, Quebec, and Toronto, Ontario, in Canada, for example, had a mix of six- and seven-digit telephone numbers from 1951 to 1957, and did not have DDD until 1958. Whitehorse, Yukon, had seven-digit numbers starting in 1965, but the necessary switching equipment was not in place until 1972. San Francisco required the special area code 318 due to temporary routing requirements.