Programmable calculator to use magnetic strips were the HP-41C and TI-59. Continuous memory does not lose its content when the calculator is switched off. With continuous memory the user can, for example, change batteries without losing the entered programs. Compact Cassettes offered a simple, inexpensive alternative to magnetic cards. Usually, an interface module, such as the Casio FA-1, was used to connect the calculator to an ordinary cassette recorder and digital data were encoded as frequency-shift keyed audio signals. Sharp and Hewlett-Packard also sold dedicated micro- or mini-cassette recorders that connected directly to the calculator. These set-ups, while being more practical and
Sumlock ANITA calculator "no binary stunts here!". Similar to the Comptometer calculating machines of the time, the ANITA had a full keyboard, a feature that was unique to it and the later Sharp CS-10A among electronic calculators. Being silent and very quick in operation, and the only electronic desktop calculator available, the ANITA sold well, reaching nearly 10,000 units per year by 1964. 1961 was a doubly notable year for the Bell Punch Company since it then also amalgamated its calculator division with the British operation of Comptometer Corporation of Chicago, U.S.A. (formerly the Felt & Tarrant Manufacturing Co.), to form Sumlock Comptometer