An electronic-mechanical device, also called a teleprinter, for preparing, storing, transmitting, and receiving messages over a telegraph or data communication circuit. The term teletypewriter was used first for teleprinters utilized in teletypewriter exchange (TWX) service in the early 1930s. It was later applied to terminals used in other services, and became interchangeable with the terms teleprinter and printing telegraph terminal. A generic term, it should be used instead of Teletype, which is a registered trademark of the AT&T Teletype Corporation. Teletypewriters were invented by several individuals in the early 1900s, initially being adaptations of the commercial typewriters of the day. Relays, magnets, and solenoids were added to provide telegraph signal generation from the operation of the typewriter keyboards, and caused the typebaskets or typewheels to print automatically on sheets of paper.