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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 calcualator.

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.

To learn more about the Compet 20, see the Old Calculator Museum exhibit for the Sharp Compet 20.