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From: hrs1@cbnewsi.att.com
Newsgroups: comp.dcom.telecom
Subject: Re: Which Came First?
Message-ID: <12877@accuvax.nwu.edu>
Date: 1 Oct 90 23:19:36 GMT
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X-Telecom-Digest: Volume 10, Issue 702, Message 1 of 12


In article <12837@accuvax.nwu.edu>, 0003209613@mcimail.com (Sandy
Kyrish) writes:

> Regarding why touch-tone pads put the "1" on the top left while adding
> machines put the "7" on the top left ... In 1983, I was doing
> historical research and I read that the early Touch-Tone pads WERE
> configured like adding machine pads -- but the early electronic
> switching systems couldn't handle rapid entry of DTMF, and people
> proficient with adding machines could literally "outdo" the switch.
> Bell engineers flipped the keypad to slow these people down.  If this
> is indeed true, will some loyal TC reader please tell me where I found
> that reference?  I've often wanted to quote this vignette but can
> never remember just where I read it.

An interesting story, but not true.  Research was done on button order
at (AT&T) Bell Laboratories in the late fifties by Dick Deininger and
others, and published in the Bell System Technical Journal.  They
found that the 1-2-3 order was best, i.e. faster with fewer errors,
for people who were not familiar with keypads.  In those days, of
course, calculators were mechanical and used by a relatively small
part of the population.  Individuals who were used to the 7-8-9 order
of course were faster on that pattern.  Since most of the population
of prospective telephone keypad users were not trained on 7-8-9, the
1-2-3 pattern was chosen.

Similar studies were performed in Sweden, with similar results.  It
was because of these human factor studies that CCITT standardized on
the now familiar 1-2-3 pattern.


Herman Silbiger
hsilbiger@attmail.com