Why is Telephone Keypad and Calculator Keypad Different?

Have you ever noticed that telephone keypad and calculator keypad are different? ;)

There are many theories explaining this difference, we will jot down some of the points.

The First Theory on Telephone Keypad

The first theory deals with the telephone's circuitry and tone-recognition hardware. When the touch-tone telephone were being designed in the years of 1950s, the calculator designers had already established a layout that had 7, 8 and 9 across the top row of the keypad, Data entry people and others who frequently used calculators were quite adapt to this keypad and its navigation style.
This was a problem because these people could hit up their numbers very quickly as they were quite comfortable with the navigation style of calculator keypads but the telephone keypad had a problem in it, The telephone keypads did not recognize the fast typed numbers, The tone dialing technology present in these keypads were not effective in picking up quick number dials on keypads hence the pace had to be slowed down to increase the effectiveness of them.

That is why the layout of telephone keypad had to changed (infact reversed) inorder to make them effective at their work with telephones.

The Second Theory

A second theory refers to a study done by Bell Labs in 1960. This study involved testing several different telephone-keypad layouts to find out which was easiest to master. After testing several layouts, including one that used two rows with five numbers each and another that used a circular positioning, it was determined that the three-by-three matrix that had 1, 2 and 3 across the top was the easiest for people to use.

The Third Theory

Another theory is based on the layout of a rotary telephone. On a rotary dial, 1 is at the top right and zero is on the bottom. When designing the new touch-tone keypad, putting the 1 on the top-right didn't make much sense, because Western writing is read from left to right. But putting 1 on the top-left, and the subsequent numbers to the right, did make sense. Using that formula, the resulting rows fell into place, with zero getting its own row at the bottom.

Well none of the above theories exactly tell us why the number pads of telephone keypad and calculator keypads are different. but it is a fact that telephone keypad layouts are used in the new ATM Keypads and other newly invented machines that use keypads, hence telephone keypad wins the battle! :D