After entering the business of timepieces in 1974, Casio released watches with various advanced features, including a calculator function (C-80 released in 1980), and a dictionary function (T-1500 Walking Dictionary released in 1982). The company wanted to see the wristwatch evolve from a simple device for telling time to an information device on the wrist.
As part of this progress, the Databank Telememo 10 (CD-40) released in 1984 had a databank function that could save and recall 10 groups of 16 letters or numerals, thereby eliminating the need to carry a personal phone-number organizer. This watch further advanced the concept of an information device on the wrist, and became a major hit product, selling a record total of six million units in the five years after its release. After that, Casio put out a whole series of databank watches, featuring Japanese kana display, timetable, autodial, and other functions.