Before we begin, a quick note: much of the following information was gathered from several public websites and blogs. I’ve pulled it together here in plain language to help explain what T-Coils are and why they matter.

The history of T-Coils (short for telecoils) goes back to 1937, when Joseph Poliakoff of Great Britain patented the first magnetic induction loop communication system.

A T-Coil is a tiny copper wire coil built inside many hearing aids. Think of it as a miniature antenna. Its job is to pick up magnetic signals sent out by an induction loop (also called a hearing loop) and turn them into clear sound directly inside the hearing aid.

Originally, T-Coils were designed for use with telephones. They detected the magnetic field coming from the speaker coils in the phone, allowing the hearing aid to pick up only the phone’s signal—without all the background noise or echo. This made voices sound much clearer and conversations much easier to understand.

Over time, people found other clever uses for T-Coils. By the 1950s, they were being used to listen to radios and TVs through small “loop pads.”

For example, around 1956, the Sonotone Corporation of Elmsford, New York produced a miniature loop pad that connected to a radio or TV using two simple alligator clips. You’d clip the leads to the speaker terminals, switch your hearing aid to the “T” setting, and—voila!—you had an early version of a personal hearing loop system.

By the 1970s, room-sized hearing loops started to appear in public spaces. Later came low-powered radio frequency (RF) systems—small transmitters that send audio wirelessly to receivers.

When a venue uses one of these RF systems to meet ADA hearing access requirements, visitors can borrow a small, battery-powered receiver. These usually come with either:

• A wired earpiece, or

• A T-Coil-enabled lanyard (my personal favorite!).

Since my hearing aids are T-Coil compatible, I simply wear the lanyard and switch my hearing aids to the T-Coil setting. Instantly, the sound from the venue streams directly into my ears—crystal clear and free from background noise.

For those without T-Coil hearing aids, the other option is to use the provided “D-style” earpiece or plug in your own earbuds. And if you happen to know the exact radio frequency the venue uses, you can even tune in using a portable radio—just like the old days of the Walkman

Sample Assisted Listening Devices