Assistive devices and technical aids (Additional references)

Types of commonly-used assistive devices

Assistive Devices and Technical Aids

Assistive Listening Systems
systems that are used to augment regular audio systems – primarily used by persons who are Deaf, deafened, or hard of hearing. There are four commonly-used types of assistive listening systems (see next heading for further information).
Electronic Communication
the transfer of information via telecommunication technologies (e.g. the internet, fax machines, remote video/audio conferencing, e-mail, mobile and smart phones, text and instant messaging, etc.).
TTYs / TDDs or Textphones
a teletypewriter (TTY) or a telecommunications device for the Deaf (TDD) that transmits written text via the telephone line – primarily used by persons who are Deaf, deafened, or hard of hearing, persons who have a speech impairment and by people who wish to phone a Deaf, deafened, or hard of hearing person who uses a TTY.
Telephone Relay Service
a service that allows real-time conversation by providing a third party who acts as a bridge between telephone users who communicate by voice and those who communicate by TTY – primarily used by persons who are Deaf, deafened, hard of hearing, persons who have a speech impairment or people who wish to phone a Deaf, deafened, or hard of hearing person.
Visual Aid
a device that helps a person to see better, such as a magnifying glass or a video telescope – primarily used by persons who are partially sighted.
Volume Control Phones
telephones that allow the user to adjust the volume of sound received through the telephone – primarily used by persons who are hard of hearing.
Volume Control Telephones with Flux Coil
flux coils located in telephone receivers which convert magnetic energy into electrical energy that can then be picked up by hearing aids equipped with a "telephone" switch (T-switch), which amplifies sound – primarily used by persons who wear hearing aids.
Smart phone, tablet, or e-reader
these are mobile devices which combine the functions of a personal digital assistant, a wireless device (capable of sending and receiving wireless data), and, in some cases, a cellular phone (capable of placing phone calls). These devices can provide useful features for persons with disabilities. On some devices, people who are blind or partially sighted can access voice over technology, zoom functions, large text, white on black, speaker selection and speak auto-text features on their mobile device. For people who are Deaf, deafened, or hard of hearing, there are custom vibration settings that can be assigned according to preference, and LED flash alerts for incoming phone calls or emails. Often, mobile devices employ the use of "apps." Some apps pull content and data from the Internet and others contain all of the data within the program so that it can be accessed offline. Some of these apps are specifically designed for persons with disabilities.

Assistive Listening Devices

Assistive listening devices (ALD) are used to augment regular audio systems and are used primarily by persons who are Deaf, deafened, or hard of hearing. These devices assist with person-to-person communication, reception of digital media (e.g. a watching a film at a movie theatre), communication via a telephone, and wayfinding (e.g. proximity alerts). The following are examples of commonly-used ALDs:

FM System
assistive listening systems that transmit sound via invisible FM radio waves. The systems consist of a transmitter and receiver. The receiver picks up the speech signal and sends it to the listener's ears through attached earphones. The FM receiver may also be coupled to T-switch-equipped hearing aids.
Magnetic (Induction) Loop System
assistive listening systems that transmit sound via invisible inductive (electromagnetic) energy. Induction loop systems consist of a "loop" of wire that is placed around the listening area (such as a ticket counter), a special amplifier and a microphone for the primary speaker. Speech signals are amplified and circulated through the loop wire. The resulting signal is picked up and amplified by the T-switch found in many hearing aids, vibrotactile devices, cochlear implant systems, or by induction loop receivers with headphones.
Infrared System
assistive listening systems that transmit sound via invisible infrared light waves. Infrared systems consist of one or more infrared light emitters which broadcast the speech signal. The speech signal enters the emitter microphone and is sent to the infrared receiver worn by the person who is hard of hearing, via either headphones or T-switch-equipped hearing aids.
Direct Wire System
hardwired or Direct-Audio-Input assistive listening systems that require a direct electronic connection between the source and the listener. The typical hardwired system consists of a microphone wired to an amplifier. One person wears a receiver (i.e. headphones, hearing aid, neckloop), which is connected to the amplifier.
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