Calculator watch financial functions (in the Casio CBA-10). Usually calculator watch operates with eight digits number, however, calculator watch can operate with 6 digits (for example, Casio C-801) or 10 digits (Casio CBA-10) numbers. Calculator watches first appeared in the mid 1970s introduced by Pulsar (1975, then a brand of the Hamilton Watch Company) and Hewlett Packard. Several watch manufacturers have made calculator watches over the years, such as Pulsar and Timex, but the Japanese electronics company Casio produced the largest variety of models. In the mid-1980s, Casio created the Databank calculator watch, which not only performed calculator functions, but also stored
Koyo Electronics Corporation Limited Koyo Electronics Corporation Limited Koyo Electronics (Kōyō Denki) and its subsidiary Koyo Electronics Industry (Kōyō Denshi Kōgyō), often collectively referred to as just Koyo, are Japanese electronics companies based in Kodaira, Tokyo that manufactured radios since 1955 until 1973, and now its subsidiary manufactures industrial electronics devices and factory automation control systems. Their first product was a vacuum tube radio released in 1955, and their first transistor radio was the KR-6TS-1 radio released in the spring of 1957 at the price of 14,000 yen. Through the 1960s, Koyo had manufactured and sold millions of portable transistor radios, particularly, their best-selling