Automatic Switching for Nationwide Telephone Service

Abstract

A plan for automatic long distance switching, which will ultimately embrace the entire area of the United States and extend into Canada and perhaps Mexico, has been formulated and important steps have been taken toward its realization. The plan contemplates that when a telephone customer places a call with a long distance operator, this operator will be able to establish a connection to any desired telephone simply by playing a 10 or 11 digit code into an automatic mechanism. She will receive distinctive signals when the called telephone answers or when the telephone or the toll circuits are busy. She will completely control the establishment of the connection and will have available to her the information necessary for proper billing of the call. The plan also contemplates that telephone customers will ultimately be able to dial long distance calls themselves, wherever may be the locations of the calling and called telephones.

Operations Research at Bell Laboratories Through the 1970s: Part I

“…Alva B. Clark and Osborne (1952), with J. J. Pilliod (1952), used these technologies to design a new switching network.…”