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
Electric Telegraph Company descendant of Cooke's Electric Telegraph Company. Records of the Electric Telegraph Company (33 volumes), 1846-1872, the International Telegraph Company (5 volumes), 1852-1858 and the Electric and International Telegraph Company (62 volumes), [1852]-1905 are held by BT Archives. Electric Telegraph Company The Electric Telegraph Company was the world's first public telegraph company, founded in the United Kingdom in 1846 by Sir William Fothergill Cooke and John Lewis Ricardo, MP for Stoke-on-Trent. At creation the company purchased all the patents Cooke and Wheatstone had obtained to date. It merged with the International Telegraph Company in 1855 to become the Electric and International