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 other products, such as taximeters. In 1976 Rockwell decided to exit the calculator market, by which time cheap calculators had markedly reduced the profitability of the industry. Sumlock Anita Electronics was closed down and the ANITA name was sold to a marketing company and soon disappeared. The rest of the Bell Punch Company, which was completely independent of Rockwell, continued in business to about 1986 when it was closed down. Sumlock-Anita Electronics also assembled in Britain some of the Rockwell hand-held calculators, including Rockwell models "8R", "10R", "18R", "20R", "21R", "30R", "31R". The "Panaplex" is a gas-discharge display, using 7