Telephone Keypads versus Calculator Keypads

Summary: If you’ve ever worked at a job that required you to switch off between a calculator and a telephone every now and again then no doubt you’ve noticed that the key pads are backwards: on the phone the number “1” is in the upper left and on a calculator it is in the lower left. So what gives?

The first keypads were created for cash registers and had the “1” in the lower left. When calculators were invented they followed suit. Enter the telephone system. When Alexander Graham Bell, the man who invented the telephone, came up with the idea, operators were used to connect people – you didn’t simply pick up your phone and dial with reckless abandon. But reach into the dark recesses of your memory – or your basement – and I’ll bet that somewhere back there there’s a rotary telephone. Not that cool, antique telephone of the candlestick variety that’s probably worth some money. I’m speaking of the big clunky kind that was frequently used to hit the bad guy over the head with on 1970s detective shows.

When we switched from the old telephones of the pulse (rotary) variety to the key pad (tonal) system the calculator key pad presented a couple of problems. First was that people were used to having the “1” at the top where the rotary “1” was. But the second, and more confusing, problem was with the letters assigned to each number. Phone numbers originally began with letters (KLondike 5, etc) and the number “1” was set aside for special functions, so the alphabet began with the number “2.” If the keypad was arranged with the “1” in the lower left, the letters would read left-to-right from the bottom up – not the most intuitive application of our alphabet.

So why not make it easy for all eternity and just rework the touch tone telephone keypad? Well, the decision wasn’t just random. Back in the 1960s when touch-tone telephones were not quite on the market, AT&T, the only telephone service provider available, had their industrial designers researching keypad designs and user interfaces. What they found was that there were far fewer dialing errors when the “1-2 & 3” were at the top rather than the bottom. In addition, according to Bob Ford of AT&T’s Bell Laboratories, when the research was conducted calculator companies were consulted and it was discovered that no research had been done on the layout of the calculator keypad, a story that both Sharp and Texas Instruments say is plausible.

So it’s really very simple: we’re not exactly comparing apples and oranges, but in spite of the fact that we’re looking at two identical things, in this case keypads, they evolved from two entirely different sources, cash registers and rotary telephones.

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