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 and took on Kitz as the leader of a project to develop an electronic version of the company's mechanical calculators. To help confidentiality the project was given the code-name ANITA. Since the company had production lines capable of manufacturing precision mechanical parts by the thousand, the first experimental models were mechanical and electronic hybrids. However, these proved impractical and a purely electronic design was pursued. Being the first in the field there were several major technical areas that required considerable development: However, the main constraint was to be the cost of the calculator. The cheapest electronic computer then cost approximately