Bell Labs is known for the development of the transistor, C / C++ programming language, Unix, the laser, and – brought to my knowledge today – the design of the modern phone dial. 

old phone layout push button

The famous research and development laboratory tested more than fifteen phone dial button layouts, ranging from the familiar clockwise and anti-clockwise increasing numbers, to odd stair-like designs, and crosses.

After thorough experimentation, the list came down to just two layouts: the one we all use today, and the opposite layout used in calculators, and other generic number pads. Further testing proved the former one to be more efficient, and that’s the phone dial they used when switching from rotary dial phones to push button ones.

phone button layouts tested by bell labs

See the video embedded below to see a summary of the designs.

Source: Gizmodo

Image Source: David Merfield