Answer Geek: Calculator vs. Phone Layouts

<br> -- Q U E S T I O N: Why do the numeric keypads on computers and calculators reverse the configuration on a telephone? I’m certain that thousands of wrong numbers are dialed daily because of this. — David K.

Q U E S T I O N: Why do the numbers on telephones go from 1 in the top left corner to 9 in the bottom right, while calculators and computer number pads go from 1 in the bottom left corner to 9 in the top right corner? — Joel K.

A N S W E R: A wonderful question, gentlemen, and something that I have puzzled over myself. After all, here are three devices that we use on a daily basis, and they all share a basic layout — an array of 10 numbers in a three-by-three arrangement with the zero sitting down below. Yet the numbers are reversed. So what gives? Why aren’t all such devices created equal, anyway?

Let’s first set the context. The time is the late 1950s. The place, Bell Laboratories, where researchers are preparing to introduce an alternative to the rotary telephone, something they called push-button dialing (which later came to be marketed as “Touch Tone” dialing). The question: how to arrange the numbers.

There were two logical models, of course. The existing rotary phone with its circular dial and counterclockwise number arrangement, with the 1 sitting in the upper right, was one. The calculator was the other. 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.

One common explanation for the discrepancy between the phone and the calculator is that phone company engineers intentionally reversed the calculator layout because their research showed that people who were already adept at using a calculator punched the buttons too quickly for the telephone switching equipment to correctly register the numbers. But accounts from people who worked for Bell Labs at the time indicate that this version isn’t necessarily the case.