Telephones and Calculators: Why Different Keypad Arrangements?

If you think about it, it is a little strange that the calculator and the touch-tone telephone have keypads that share many identical components and yet for some unknown reason, have exactly opposite layouts for their keypads. Both the touch-tone keypad and the calculator were made available to the general public in the early 1960s and they were both descended directly from earlier prototypes.

Although no one can say for sure, theories abound. Some say the reason for the disparity between keyboard arrangements lies in the telephone’s circuitry and tone-recognition hardware. This technology could not operate as fast or as efficiently as data entry professionals could dial the numbers. The telephone designers came after the calculator and its creators feared interference with the layout might adversely affect dialing speed.

While the above theory makes perfect sense, so does the next one. A study done by Bell Labs back in 1960 entitled: Human Factor Engineering Studies of the Design and Use of Pushbutton Telephone Sets involved testing of different telephone-keypad layouts to determine which was the easiest to use. The three-by-three matrix that had 1, 2 and 3 across the top turned out to be the simplest to master.

Still others believe that the answer to this conundrum lies in the basic layout of the rotary telephone itself. The 1 is at the top right and zero is on the bottom on a standard rotary dial, but due to the fact that Western writing is read from left to right, the creators of the newer touch-tone keypads did not consider such a placement practical. Instead, they placed the 1 on the top left and all subsequent numbers to the right. This version gave the zero its very own row at the bottom.

As it stands, no one theory can remain any more than just that. The telephone-keypad layout is often used today when designing new products that utilize a keypad, such as Automated Teller Machines.

Why aren’t all such devices created equal?

It would appear that the answer, my friends, is anyone’s guess.

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