Bell Designing The Telephone Keypad

This layout is so standardized that we think about it as almost inevitable. But the layout was, in the 1950s, the result of a good deal of strategizing and testing on the part of the people of Bell Labs. And Numberphile has dug up an amazing paper – published in the July 1960 issue of “The Bell System Technical Journal” – that details the various alternative designs the Bell engineers considered for the layout. Among them: “the staircase” (II-B in the image above), “the ten-pin” (III-B, reminiscent of bowling-pin configurations), “the rainbow” (II-C), and various other versions that mimicked the circular logic of the existing dialing technology: the rotary.