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
Sumitomo Electric Industries in optical transmission networks and optical communication devices. The Sumitomo Electric Group's electronics division supplies various products to manufacturers of smartphones, flat-screen televisions, and other highly advanced electronic goods. Products include base material, wiring, and components for compact and lightweight devices with high functionality, such as flexible printed circuits (FPCs), electronic wires, heat-shrinkable tubing, fine polymer products, and compound semiconductors. Capitalizing on compound semiconductor development and manufacturing-knowledge accumulated over many years, Sumitomo Electric succeeded in developing and mass-producing the world's first gallium nitride substances. Sumitomo Electric also continues to be the leading manufacturer of composite semiconductors (GaAs, GaN, InP), which