All-number calling is a telephone numbering system that was introduced in the United States in the 1960s and 1970s.
Until the 1950s, local telephone numbers consisted of an exchange and a 5-digit phone number. A New Yorker's phone number might be CHelsea 4-5034, which another user would dial (once dial service was available—until the 1930s use of panel switch, phone calls had to be manually connected by a switchboard operator) a two-letter code for the exchange followed by the 5-digit number. When the phone company began running out of memorable telephone exchange names, it tried to replace it with "all-number calling."[1] This sparked an intense outcry among urban users, who considered all-numeric calling to be dehumanizing. [2][3]
Opponents created a variety of organizations to oppose all-number calling, including the Anti-Digit Dialing League and the Committee of Ten Million to Oppose All-Number Calling to pressure AT&T to drop the plan.[4]