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# Why do numbers on a telephone and those on a calculator start from opposite directions?

Question #52021. Asked by ranan. (Oct 29 04 4:38 AM)

gtho4

This is one theory:

Before 1964, calculators were either mechanical or electronic devices with heavy tubes. The key pads on the first calculators actually resembled old cash registers, with the left row of keys numbering 9 on top down to 0 on the bottom. The next row to the right had 90 on top and 10 on the bottom, the next row to the right had 900 on top, 100 on the bottom, and so on. All of the early calculators were ten rows high, and most were nine rows wide. From the beginning, hand-held calculators placed 7-8-9 on the top row, from left to right.

Before the touch-tone phone, of course, rotary dials were the rule. There is no doubt that the touch-tone key pad was designed to mimic the rotary dial with the "1" on top and the 7-8-9 on the bottom. According to Bob Ford, of AT&T's Bell Laboratories, a second reason was that some phone-company research concluded that this configuration helped eliminate dialing errors. Ford related the story, which may or may not be apocryphal, that when AT&T contemplated the design of their key pad, they called several calculator companies, hoping they would share the research that led them to the opposite configuration. Much to their chargin, AT&T discovered that the calculator companies had conducted no research at all. From our contacts with Sharp and Texas Instruments, two pioneers in the calculator field, it seems that this story could easily be true.

It has also been suggested that if the lower numbers were on the bottom, the alphabet would then start on the bottom and be in reverse alphabetical order, a confusing setup. This might have entered AT&T's thinking, particularly in the "old days" when phone numbers contained only five digits, along with two exchange letters.

http://www.vcalc.net/Keyboard.htm

 Oct 29 04, 5:40 AM

### Other Similar Questions & Answers

 Why are numbers 1-9 on a mobile phone arranged with 1,2,3 on the top line, 4,5,6 on the line underneath, then 7,8,9 on the bottom line, but on a calculator it's the opposite: 1,2,3 on the botttom line, 4,5,6 on the middle, then 7,8,9 on the top. Who decided this?

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