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Short answer: an induction loop (also called a hearing loop) is an assistive listening system that sends sound from a source such as a microphone, public address system or TV as an electromagnetic signal through a wire loop around a room. A telecoil inside many hearing aids and cochlear implants, or a separate loop receiver, picks it up directly (NIDCD, checked 2026-10-31). It reaches only people who wear such a receiver and are within or near the loop.
General information only, not medical advice. Whether a given hearing aid or implant has a telecoil is stated in that device’s own documentation.
What an induction loop system is
The U.S. National Institute on Deafness and Other Communication Disorders (NIDCD) describes hearing loop, or induction loop, systems as systems that “use electromagnetic energy to transmit sound.” It lists four parts: a sound source (a public address system, microphone, or a home TV or telephone), an amplifier, a thin loop of wire that encircles a room or branches out beneath carpeting, and a receiver worn in the ears or as a headset.
A hearing loop can be connected to a public address system, a television or any other audio source, and some loop systems are portable. NIDCD names hearing loop systems, frequency-modulated (FM) systems and infrared systems as the assistive listening device (ALD) systems used in large facilities.
The U.S. Access Board’s ADA standards (section 106.5) define an assistive listening system as an amplification system that uses transmitters, receivers and coupling devices to bypass the acoustical space between a sound source and a listener “by means of induction loop, radio frequency, infrared, or direct-wired equipment.”
How an induction loop works in practice
Amplified sound travels through the loop wire and creates an electromagnetic field. A telecoil, which NIDCD describes as a coil of wire installed inside many hearing aids and cochlear implants, receives that signal and turns it back into sound inside the device. NIDCD says this process eliminates much of the distracting background noise. To pick up the signal, the listener must be wearing the receiver and be within or near the loop.
The telecoil was originally designed to make sounds clearer over the telephone and is also used with other assistive listening devices. For listeners without a telecoil-equipped hearing aid or cochlear implant, NIDCD notes that loop receivers with headsets can provide similar benefits, without the customised sound that matches an individual’s hearing-loss pattern. For the device side in detail, see the guide to hearing aid telecoils.
A venue that has a loop can show it. NIDCD reproduces the hearing loop logo, which “informs people that a public area is looped.”
Where it sits among assistive listening systems
The table below maps the main assistive listening system types against two sources: NIDCD’s list for large facilities and the ADA definition of an assistive listening system.
| System type | Named by NIDCD for large facilities | Named in the ADA definition of an assistive listening system |
|---|---|---|
| Induction loop (hearing loop) | Yes | Yes (“induction loop”) |
| FM / radio frequency | Yes (frequency-modulated systems) | Yes (“radio frequency”) |
| Infrared | Yes | Yes |
| Direct-wired | Not named | Yes (“direct-wired equipment”) |
The loop is the type whose receiver is the telecoil many listeners already carry in their own devices. For the radio-based alternative, see what an FM system is.
The standard behind loop performance
The International Electrotechnical Commission publishes IEC 60118-4:2014 (edition 3.0, 2014-12-11), “Electroacoustics – Hearing aids – Part 4: Induction-loop systems for hearing aid purposes – System performance requirements.” Its scope covers audio-frequency induction-loop systems that produce an alternating magnetic field at audio frequencies and are intended to provide an input signal for hearing aids operating with an induction pick-up coil (telecoil) (IEC webstore, checked 2026-10-31). Because the standard is about the loop system as a whole, “conforms to IEC 60118-4” is a different statement from describing a single component.
Questions to settle for a facility installation
Facility readers can ask a supplier or installer to state the following in writing.
- Which audio sources will feed the loop? NIDCD lists a public address system, microphone, TV or telephone as typical sources.
- Is the system installed (wire around a room or under carpeting) or portable?
- Does the supplier state conformance to IEC 60118-4 for the installed system?
- Are loop receivers with headsets part of the offer, for listeners who do not have a telecoil?
- Will the looped area carry the hearing loop logo so listeners know to use it?
Clinics that stock hearing-related accessories can also see the audiology clinic supply checklist.
Common misunderstandings
A loop is not an FM or infrared system
A loop delivers sound through an electromagnetic field to a telecoil or loop receiver, while FM and infrared are separate system types in NIDCD’s list. They are alternatives for a venue, not names for the same thing.
A loop does not reach every hearing aid
NIDCD says telecoils are built into “many” hearing aids and cochlear implants, not all. Without a telecoil or a loop receiver the loop signal is not picked up.
Anywhere in the building is not “in the loop”
The listener must be within or near the loop. That is why the logo and a clearly defined looped area matter.
FAQ
What is a hearing loop system?
A hearing loop system is another name for an induction loop system: a sound source, an amplifier and a wire loop around a space that sends sound as an electromagnetic signal to a telecoil or loop receiver (NIDCD).
What is the difference between an audio induction loop and an induction loop system?
Both phrases are used for a wire loop that carries an audio-frequency signal as a magnetic field. The wording in the IEC 60118-4 scope is “audio-frequency induction-loop systems.”
Can a loop be connected to a TV or PA system?
Yes. NIDCD states a hearing loop can be connected to a public address system, a television or any other audio source.
Sources
- NIDCD, Assistive Devices for People with Hearing, Voice, Speech, or Language Disorders, checked 2026-10-31.
- IEC, IEC 60118-4:2014, Induction-loop systems for hearing aid purposes – System performance requirements, checked 2026-10-31.
- U.S. Access Board, ADA Accessibility Standards, section 106.5 definition of assistive listening system, checked 2026-10-31.
