With the birth of NORAD and the SAGE system, 48 AN/FSQ-7s, the first mainframe produced by IBM, were used. With 25,000 vacuum tubes, it was the fastest and most expensive computer in the world. SAGE collected analog data, converted it to digital, and transmitted it over AT&T telephone lines. It also served as a development and testing laboratory for technologies that would dominate the Third and Fourth Industrial Revolutions.
