Originally published at: http://www.howtogeek.com/171687/phone-button-history-how-the-number-pad-layout-was-chosen/
During the early part of the 20th century, the only way to call someone was via a rotary dial telephone, but by the 1950s research for the first number pads for telephones had begun. Numberphile looks at the original research and number pad designs that were put forth and tested, all leading to the layout we are familiar with today.
I was a consultant at Bell Labs when the phone button layout was chosen and worked closely with the Human Factors department, The driving force behind the change was not the development of a faster keyboard but the elimination of the very complex and costly mechanical system of the dial. Take a dial phone apart and you will see what I mean. The dial mechanism is a kudge of gears, governors, and contacts. Not only was it the most costly part of the telephone but it was the part most prone to failure. Multiply the cost by 200 million telephones and you have a powerful incentive. ANY of the pushbutton concepts would have been acceptable. The engineers in the group far preferred the calculator keyboard but management felt that the phone using public was too stupid to use it.
Seriously? Filled with gears? Yeah! Now I know where to get the gears for my DIY toy car!
I was working for the old AT&T/Ma Bell back when the changeover from dial to "touchtone" began (yes, I'm well-aware it was a very long time ago).
It wasn't only the phone dials that were full of gears, but the central offices worked on the old "step" system - rotary switches by the thousands having to rotate, move, make connections to other switches every time some one picked up a phone. When you dialed, as your dial clicked and returned, these office switches were also clicking up, down, or over in response to your dial. This took many, many employees just to keep these mechanical switches working correctly - a never-ending task. However, the old offices, which were everywhere, would not work with the tone pulses sent out by the new TT phones (there were some temp. fixes possible during the changeover of offices, sort of). Regardless, the phone company Central Offices were all eventually cut over at first to what I believe were called "Crossbar" offices. As more and more were switched over, there was less and less need for men to do the work. In the small town of Moraga, California, there were, at one time, two full-time employees just running wires and maintaining the electro-mechanical switches - after the cutover, there were none; it was handled remotely. Eventually, it was all solid state, all done remotely from centralized computers.
One other thing - at first, if you wanted to change over to push button, you not only paid a service fee to change, but you also paid a monthly fee for having this fancy new style of phone.
There WERE people like my mother - she absolutely refused to get a "push-button" phone, and kept her old black rotary dial wall phone until the day she died.