Telephone devices for the deaf (TDD)
TDDs let you call another person who has a TDD. You can type messages that are displayed on a screen. TDDs come in many different models. They can also be used with telecommunication relay services.
Another telephone device, a telecoil, can be used with certain hearing aids. The telecoil is a small magnetic coil in the hearing aid. It helps improve sound during telephone calls.
Amplifiers that are portable or built into the receiver of a phone can help increase the volume for the listener. Some people may have trouble hearing a phone's high-pitched ring. That sound can be replaced with a lower-tone bell or buzzer. Or with a visual alert.
Radio, stereo, and TV amplifiers
These amplifiers can connect with hearing aids. They send audio signals directly from a radio, stereo, or TV with a receiver. Whether using headphone devices or wireless devices, these amplifiers let a hearing-impaired person listen to radio, stereo, or TV at a comfortable level. There is no background noise.
Visual signaling devices can alert a hearing-impaired person to auditory signals he or she can't hear. Visual signaling devices that flash a light are available for phones, doors, alarms, baby monitors, and more. Other signaling devices include a vibrating option that can wake up a hearing-impaired person.
Captions for the hearing-impaired
Captions are the words shown on a TV screen that follow along with the audio part of the program. Hearing-impaired viewers can read the captions to follow the dialogue and action at the same time. Captions also describe sound effects that are important to the story line.
Captions can be open or closed. Open captions are on every TV. Closed captions require a set-top decoder. Or built-in decoder circuitry. Closed-caption technology is widely available now. So open-caption technology is rarely used.