Why are the number pads of calculators and telephones the opposite way around

A.� There are several theories as to why these two systems that share the same ten digits in three rows with the zero on a row by itself have developed with the opposite configuration to each other.

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Q.� Like what

A.� Theory number one stems from research carried out at Bell labatories in the 1950's into developing keypad telephone to replace the circular dial.

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When it came to actually arranging the numbers on the pad there were two obvious choices: to either have the 1 in the top right hand corner with the rest of the numbers running right to left, as near as possible the circular dial, or to reproduce the same layout as the early calculators, with the 1 in the bottom left hand corner and 7, 8 and 9 running across the top.

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Q.� But neither was used

A.� No, on telephone number pads the 1 is in the top left hand corner.

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Q.� So why not copy the calculator layout if that was what people were used to regarding number pads

A.� The theory goes that it was precisely because people were used to this layout that an alternative was adopted. The telephone developers were concerned that people were so adept at pressing the numbers that they would dial numbers too quickly for the telephone system to cope. So the telephone manufacturers produced a keypad the reverse of the more familiar calculator pad.

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But of course this is just one theory.

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Q.� What are the others

A.� Another one merely suggests that research carried out by telephone companies suggests that the configuration that was adopted was the one that the majority of people could use. After all not everyone in the 1960's used a calculator on a regular basis.

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Q.� Rather boring

A.� Yes, but it also made sense to lay the numbers out in this way because when it came to matching them with letters it was much more logical to have the alphabet running left to right from the top to the bottom.

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�And so the third possible option, based on a row and column layout of the existing circular dial, with the 1 at the top right hand corner was also ruled out, as this would have meant that the letters were running right to left, the opposite direction to western writing.

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Want to know why a piece of modern machinery is configured the way it is Click here to ask The AnswerBank.

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by Lisa Cardy