A text telephone that allows people with very limited hearing or no hearing to communicate over the phone. Rather than speaking into the phone and listening, a person types and reads. It uses Baudot code which has largely been rendered obsolete by the widespread use of digital technology.

An optional accessory to the TEMPO cochlear implant by Med-El that allows the user to take advantage of two features–a built-in telecoil for accessing certain assistive listening devices, or an external microphone.

A telecommunication system that uses operators (called Communications Assistants [CA]) to facilitate telephone calls to or from people who are deaf or have limited hearing and also people with speech disabilities. This includes text to voice (TTY), Voice Carry Over (VCO), Captioned Telephone Service, Video Relay Service (VRS) and several other modes.

This term has fallen out of favor as the Deaf community never liked it. They use TTY, the abbreviation for teletype instead. (See Teletype.)

A tiny coil of wire built into many hearing aids that allows the hearing aid to pick up the magnetic fields emitted by telephones, various assistive listening devices, or induction room loops. Sometimes referred to as “t-switch” or “t-coil.”

Telecommunication Device for the Deaf. (See Teletype.)