John E. Karlin, Who Led the Way to All-Digit Dialing, Dies at 94

[CoalMinerRetired]

Highly interesting reading, IMO.

http://www.nytimes.com/2013/02/09/business/john-e-karlin-who-led-the-way-to-all-digit-dialing-dies-at-94.html?hp&_r=0

We tweak digit maps on out VoIP lines, this fellow tweaked the white dots in the holes in rotary phones, ... that's just one example. 

In 2013, the 50th anniversary of the introduction of the touch-tone phone, the answers to those questions remain palpable at the press of a button. The rectangular design of the keypad, the shape of its buttons and the position of the numbers — with "1-2-3" on the top row instead of the bottom, as on a calculator — all sprang from empirical research conducted or overseen by Mr. Karlin.

By the late 1950s, when touch-tone dialing — much faster than rotary — seemed an inevitability, Mr. Karlin's group began to study what form the phone of the future should take. Keypad configurations examined included Mr. Mallina's, one with buttons in a circle, another with buttons in an arc, and a rectangular pad.

The victorious design, based on the group's studies of speed, accuracy and users' own preferences, used keys half an inch square. The keypad itself was rectangular, comprising 10 keys: a 3-by-3 grid spanning 1 through 9, plus zero, centered below. Today's omnipresent 12-button keypad, with star and pound keys flanking the zero, grew directly from this model.

[MurrayB]

Thanks for posting this - great history. I was told that the keypad is the reverse of the calculator to prevent all the calculator operators "dialing" so rapidly due to their "touch calculating" ability they would outrun the systems capablity.

[giqcass]

It's funny how much went into something so seemingly simple that we now take for granted.

[ianobi]

A very good read. It shows how you have to consider human beings as much as technology when creating a telecom product.

I remember those first dial pads for telephones and switchboards. They were very clunky as they still had to produce loop/disconnect signalling. That was quite a few years ago ...

[Ostracus]

It's funny how much went into something so seemingly simple that we now take for granted.

The mark of a job well done is obscurity.