Old Calculator Museum Advertising & Documentation Archive
Sharp Compet 20 (Model CS-20A)
Advertisement for the Hayakawa Electric Sharp Compet 20 (Model CS-20A) Electronics Magazine, January 9, 1967
This is a most bizarre advertisement for the
Sharp Compet 20 electronic
calculator, from the strange ghostly curled appendage growing out of the
technician's hand in the photo, to the backwards Nixie tube displays at
the upper part of the photo, and the fact that the circuitry shown in the
photograph does not even closely resemble the circuitry used in the Compet
20 calculator.
Why such an awkward photo was used in this advertisement is unclear. It is
possible that the photo may have been flipped accidentally during
the setup of the ad for production, resulting in
the backward Nixie display. The strange ghost image could have been a
printing issue in the magazine that the advertisement appeared in. A copy
of this ad from another source has not been found to see if this same
artifact exists in other copies. Lastly, the photo may have been taken of
a pre-production prototype of the Compet 20's electronics long before the
design was finalized, or perhaps it is a photo of some other prototype
calculator that was under development at the time the advertisement was crafted.
At the time the advertisement appeared (January, 1967), the Compet 20 had been
on the market for quite some time, so it should have been easy to get a
photograph of a technician posed working on the actual Compet 20 electronics
rather than this photo which most certainly is not the insides of a Compet 20.
Perhaps Hayakawa Electric did not want to show the insides of an actual
Compet 20 in the advertisement for fear that competitors would closely
inspect the photograph to get clues as to the design of the calculator,
so an image of something else was used to throw off anyone with such intent.
The thought of a competitor doing such a thing is not just paranoia. In
the early days of the electronic calculator business, the designs of the
machines were considered to be trade secrets, to be carefully protected,
as, even back then, industrial espionage was not unheard of.
Whatever the reasons behind this rather odd advertisement, it does not
dilute the fact that the Sharp Compet 20 was a huge step forward from
Hayakawa Electric's first Sharp-branded calculator, the
Compet 10,
which was a lot larger and heavier, considerably less easy to operate,
had some reliability issues, and due to its lower-level of electrical safety,
was initially not able to be directly imported into many markets because
of higher electrical safety standards in other counties.
The Compet 20 addressed all of these issues, along with using a more
sophisticated architecture that set the stage for a fairly lengthy stretch
of follow-on calculator models based on the same general architecture.
At the time it was introduced, the Compet 20 was arguably the best
electronic calculator available, with great ease-of-use, an attractive
design that fit well in any office environment, a very easy to read
display, and very importantly, it consumed less space on the desktop than
other calculators on the market, was light enough to be easily moved
around as needed, was priced reasonably for its features, and was
designed for reliability and ease of service with a modular design
that significantly reduced time-to-repair if a problem did occur.
The Compet 20 is a four-function calculator with fourteen digits of capacity,
automatic or fixed decimal point, and negative number capability. The
calculator is made from a mix of discrete Silicon (the first use of
Silicon transistors in a Japanese-made electronic calculator) and
some older-technology Germanium transistors. The transistors used in the
Compet 20 were manufactured by Hitachi in Japan. The architecture of the
machine is based on on a digit parallel design, with math operations
performed a digit at a time. Digits are stored in the
calculator as four-bit binary-coded decimal numbers in transistorized
shift registers. The machine's logic uses approximately 620 transistors
and 1920 diodes, along with countless resistors and capacitors.
