Why are computer and telephone numerical keypads inversed?

Question

Why are computer and telephone numerical keypads inversed?

Answer 1

Good question.

I am guessing that it has to do with the fact that rotary dial phones pre-dated keyboards that had a numeric keypad on the side.  

In the old days rotary dial phones were numbered 1 to 9 with 0 at the end.  Letters were assigned to various numbers, 2 for example had abc assigned to it (as is the case today).  1 had no letter assigned to it so as not to be confused with the lower case l.  0 was saved to the end and was used to call the operator.

In any case when touch tone phones hit the market they needed to have both numbers and letters on them (legacy thinking I guess).

Because in English we read top to bottom, left to right, the 2 (abc) and 3 (def) needed to be on the top row, also the 0 needed to follow the 9 (as with the rotary dial phone) - which of course makes no sense numerically.

At the same time, an old underwood manual typewriter <for example> had the numbers above the qwerty keys.  These went from 2 to 9 then 0 (the lower case "l" key was used for the number 1 (and as mentioned above why the 1 on the phone was not associated with a letter)).

When keyboards with keypads to the right came out this whole convention was not required.  The grouping of all the numbers to the right, in rows of threes was great for the productivity ( of right handed people :-) ) .

I'm guessing at that time it just made sense to have the higher numbers up high and the lower numbers down low.  It also ment the 0 could be nestled underneath (before) the 1 rather than after the 9 which makes no sense at all numerically.

In any case, that’s my theory and I'm sticking to it.