Bell Labs’ Portrayal of Switching as Computing (or Not)

Abstract

Bell Labs was eager to apply evolving computing technologies and electronics to the Bell System, particularly for enabling the Bell System to be able to handle the rapidly increasing demands on the telephone network. By the mid-1940s and into the 1950s, Bell Labs had begun multiple efforts to develop electronic switching. In the late 1940s, the Switching Research group led by Deming Lewis was investigating the use of pulse code modulation (PCM) as a way of digitizing speech and building systems to leverage electronics not only for the control systems but for the switching fabric as well, particularly in the Experimental Solid State Exchange (ESSEX) [6], [23]. With the transistor’s invention in 1947, there was an eagerness to apply this technology once it became reliable enough to replace vacuum tubes, which were considered less reliable and more power hungry than relays.