Home » Why do numpads on keyboards and phones have reversed layouts?

Why do numpads on keyboards and phones have reversed layouts?

Solutons:


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.

One additional possible explanation is that with the calculator layout many calculations can be performed along the bottom two rows and the plus button only; zeroes, decimal points and the enter/equals button.

Since the main buttons are all at the bottom, it makes reasonable sense that the other numbers would count up from the bottom too.

I suspect (but have no proof) that the phone keypad layout would make typing on a calculator more difficult for most simple calculations.

I have a reasonable explanation. Since I come from mathematics background, this is the first thing that comes to mind.

Calculators

You probably have heard of the Benford’s law, also known as the “First digit law”. It says, that digits 1,2,3 occur more often than 7,8,9 when dealing with random, arbitrarily big numbers, which numbers that users type into calculators, in fact, are.

The graph is something like this and shows heavy bias against the digit “1”. Therefore it’s sensible to put digits 1, 2, and 3 to the bottom row, as it’s closer to the enter and also user reaches them easier.

enter image description here
Benford’s law (wikipedia)

Phone numbers

Since phone numbers are have limited number of digits and are in fact, randomly scattered, the Benford’s law doesn’t apply here, which means all the digits occur with similar frequencies. This might be the reason that the more natural ordering is used, since there’s no reason to complicate.

Related Solutions

Extract file from docker image?

You can extract files from an image with the following commands: docker create $image # returns container ID docker cp $container_id:$source_path $destination_path docker rm $container_id According to the docker create documentation, this doesn't run the...

Transfer files using scp: permission denied

Your commands are trying to put the new Document to the root (/) of your machine. What you want to do is to transfer them to your home directory (since you have no permissions to write to /). If path to your home is something like /home/erez try the following:...

What’s the purpose of DH Parameters?

What exactly is the purpose of these DH Parameters? These parameters define how OpenSSL performs the Diffie-Hellman (DH) key-exchange. As you stated correctly they include a field prime p and a generator g. The purpose of the availability to customize these...

How to rsync multiple source folders

You can pass multiple source arguments. rsync -a /etc/fstab /home/user/download bkp This creates bkp/fstab and bkp/download, like the separate commands you gave. It may be desirable to preserve the source structure instead. To do this, use / as the source and...

Benefits of Structured Logging vs basic logging

There are two fundamental advances with the structured approach that can't be emulated using text logs without (sometimes extreme levels of) additional effort. Event Types When you write two events with log4net like: log.Debug("Disk quota {0} exceeded by user...

Interfaces vs Types in TypeScript

2019 Update The current answers and the official documentation are outdated. And for those new to TypeScript, the terminology used isn't clear without examples. Below is a list of up-to-date differences. 1. Objects / Functions Both can be used to describe the...

Get total as you type with added column (append) using jQuery

One issue if that the newly-added column id's are missing the id number. If you look at the id, it only shows "price-", when it should probably be "price-2-1", since the original ones are "price-1", and the original ones should probably be something like...

Determining if a file is a hard link or symbolic link?

Jim's answer explains how to test for a symlink: by using test's -L test. But testing for a "hard link" is, well, strictly speaking not what you want. Hard links work because of how Unix handles files: each file is represented by a single inode. Then a single...

How to restrict a Google search to results of a specific language?

You can do that using the advanced search options: http://www.googleguide.com/sharpening_queries.html I also found this, which might work for you: http://www.searchenginejournal.com/how-to-see-google-search-results-for-other-locations/25203/ Just wanted to add...

Random map generation

Among the many other related questions on the site, there's an often linked article for map generation: Polygonal Map Generation for Games you can glean some good strategies from that article, but it can't really be used as is. While not a tutorial, there's an...

How to prettyprint a JSON file?

The json module already implements some basic pretty printing in the dump and dumps functions, with the indent parameter that specifies how many spaces to indent by: >>> import json >>> >>> your_json = '["foo", {"bar":["baz", null,...

How can I avoid the battery charging when connected via USB?

I have an Android 4.0.3 phone without root access so can't test any of this but let me point you to /sys/class/power_supply/battery/ which gives some info/control over charging issues. In particular there is charging_enabled which gives the current state (0 not...

How to transform given dataset in python? [closed]

From your expected result, it appears that each "group" is based on contiguous id values. For this, you can use the compare-cumsum-groupby pattern, and then use agg to get the min and max values. # Sample data. df = pd.DataFrame( {'id': [1, 2, 2, 2, 2, 2, 1, 1,...

Output of the following C++ Program [closed]

It works exactly like this non-recursive translation: int func_0() { return 2; } int func_1() { return 3; } int func_2() { return func_1() + func_0(); } // Returns 3 + 2 = 5 int func_3() { return func_2() + func_1(); } // Returns 5 + 3 = 8 int func_4() { return...

Making a circle out of . (periods) [closed]

Here's the maths and even an example program in C: http://pixwiki.bafsoft.com/mags/5/articles/circle/sincos.htm (link no longer exists). And position: absolute, left and top will let you draw: http://www.w3.org/TR/CSS2/visuren.html#choose-position Any further...

Should I use a code converter (Python to C++)?

Generally it's an awful way to write code, and does not guarantee that it will be any faster. Things which are simple and fast in one language can be complex and slow in another. You're better off either learning how to write fast Python code or learning C++...

tkinter: cannot concatenate ‘str’ and ‘float’ objects

This one line is more than enough to cause the problem: text="რეგულარი >> "+2.23+ 'GEL' 2.23 is a floating-point value; 'GEL' is a string. What does it mean to add an arithmetic value and a string of letters? If you want the string label 'რეგულარი...