Why do numpads on keyboards and phones have reversed layouts?

  • I came across this on the web. It's supposed to be funny, but we all know better :)

    enter image description here

    So, why are the numpad layouts different, and what are the reasons behind each?

    +1 to you sir; I too have so often wondered this and been frustrated by it.

    What's really going to bake your noodle later on is, why is the zero placed at the bottom in *both* layouts?!

    @Rahul I'm actually pretty sure about that one :). On the kbd it's because it's the most frequently used digit (in "real-life" numbers but not in phone numbers), and on the phone - so as to not break apart the row of *0# - which would be bad for all kinds of reasons. And you're not going to place that row above the other digits, because it's hardly ever used.

    @Rahul Gotta love a Matrix reference! +1

    There is also now a nice numberphile video which summarizes the history behind this "inconsistency". My personal theory is that numbers used for calculations, or just as a symbol collection are different enough use cases, that they might warrant different interfaces.

    Surprised no one mentions you generally dial a phone with your thumb and type on a keyboard with your fingers. It changes your perspective to the numbers. I prefer them different the way they are.

    @JoeMcGrath How old are you, if you don't mind me asking? :)

    @VitalyMijiritsky 29. I realize the downvoted answer at the bottom says same thing. A keyboard is going away from you. A phone is going top to bottom.

    @JoeMcGrath I'm only asking because it sounds like the question of someone who's never used a stationary phone, but grew around mobile or at least wireless phones. The fingers were heavily used on stationary phones (and actually the thumb - not so much).

    @VitalyMijiritsky Most phones are still "infront of you" (phone on a wall, pay phone, desk phone with a lot of tilt) . A flat desk phone may be closest to a keyboard. I've just never had a problem thinking of a keyboard being right and a phone being right. Now I've given it more thought than I ever wanted to.

  • dnbrv

    dnbrv Correct answer

    10 years ago

    There's this humongous article called Keyboard Trivia that has collected many of the theories and stories. The summary of facts:

    • Touch-tone key pad was designed to mimic the rotary dial with the "1" on top and the 7-8-9 on the bottom, and AT&T conducted user testing to confirm that this configuration helped eliminate dialing errors.
    • By the time when the touch-tone telephone was being designed in the late 1950s, the calculator and adding-machine designers had already established a layout that had 7, 8 and 9 across the top row.
    • Back then, the industry-standard typical calculator had nine columns of numbers, with 10 numbers in a column, the lowest digits at the bottom, starting with 0 and moving up to 9, and was basically a mechanical adding machine that closely resembled a cash register.
    • It is common practice today to use the telephone-keypad layout when designing new products that utilize a keypad, such as Automated Teller Machines.
    • When Bell Labs began exploring keypad layouts in the late 1950s they contacted all of the leading calculator manufacturers to find out why they had chosen to put low numbers at the bottom and high numbers at the top rather than the other way around. The answer, apparently, was a big shrug. It turns out that decision was largely arbitrary: no one had done any research about which layout was most convenient for users. Still, when it came time to place a numeric keypad on a computer keyboard, the calculator model with 7-8-9 at the top prevailed.

    There's also a theory that phone engineers wanted to slow down people who were fast at entering numerical data, which would jam lines and produce dialing errors, so they reversed the layout. However, records of AT&T Labs' research clearly invalidate it.

    In a left to right / top to bottom culture the telephone layout is more logical...123,456,789

    @PhillipW: That's what the AT&T research has shown.

    PhilipW: tell that to an accountant that is subject to Benford's law http://en.wikipedia.org/wiki/Benford's_law

    Here's a video explaining Bell Labs' usability studies which led to the decision. http://www.wimp.com/phonebuttons/

    isn't it a hypothesis rather than a theory about the phone engineers, i.e. something that might be true, or makes sense, sounds possible etc, but has no evidence (yet), whereas theories are often the best interpretation of a wealth of evidence and actually very close to fact in many cases ?

    I wonder what the % probability of dialling error is for each layout and vice versa for data entry with a telephone number pad.

    @PhillipW: Whether 1 to 9 goes up or down, 0 should be closer to 1 than to 9 to be more logical, as 0…9 is a natural and logical increasing order, while 1…0 is not.

    @musiphil: best argument ever heard

    @PhillipW - actually, if you understand the mechanics of the early direct-dial phone system (pre-touch-tone, and rotary dials rather than buttons), 0 at the bottom makes sense - on rotary-dial phones, 0 was after 9 because it generated _ten_ pulses on the line for dialling - so it's not really a zero, it's a ten, even in these touch-tone days.

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Content dated before 7/24/2021 11:53 AM