How Do I Know Whether My Hearing Aids Have T-Coils?

by Neil Bauman, Ph.D.

February 22, 2016

A man asked,

I just want to be sure I understand correctly that if there is no “T” switch on my hearing aid, then my hearing aid does not have a t-coil? The manual for my hearing aid says they “may” be equipped with a t-coil. They are 1996 Siemens with three programs. Could it be that the t-coil resides in one of the programs?

There is a lot of confusion about t-coils, those invaluable little coils of wire in most hearing aids that let you hear beautiful, clear sound via a loop system. neckloop or telephone.

Back in the “old days” of analog hearing aids (pre-1996), it was easy to tell whether your hearing aid had a t-coil in it or not. There was a switch on it with one position labeled “T”. This is how the t-switch got it’s name—it was a physical “T” switch.

Actually, the “T” position stood for “telephone”, not for “t-coil” because back in 1938 when t-coils were first installed in hearing aids, they had only one purpose—to let you hear on the telephone.

There were a number of variations of the t-switch. Early hearing aids had a special two-position switch labeled “M” (microphone) and “T” (telephone [t-coil]). Later, the hearing aid manufacturers combined the t-switch with the on-off switch, so it became a 3-position switch labeled “O” (off), “M” (microphone) and “T” (t-coil). (Note: sometimes the “T” position was put on the 3 or 4 position tone control rather than on the on-off switch.)

Still later, when the hearing aid manufacturers realized that there were times when a person wanted to hear via both their t-coils and their microphones at the same time, they added a fourth position to the O-M-T switch so it became O-M-MT-T, where the MT position had both the microphone and t-coil on at the same time.

This was how it was done in analog hearing aids. However, when digital hearing aids came out beginning in 1996, they dispensed with the physical switch, much to the chagrin of many hard-of-hearing people.

Instead of having a physical switch, they made it so the t-coil setting had to be programmed into one of the 3 or 4 memories these digital hearing aids now had. As a result, there no longer was any external evidence showing whether your hearing aid had a t-coil in it or not. You had to go to your audiologist or hearing aid dispenser and ask them—you couldn’t just see for yourself.

On of the “nasty” things that happened at this point was that since many audiologists and hearing aid dispensers had been brainwashed to believe that t-coils weren’t useful, they didn’t program them into any memory. Thus, you could physically have hearing aids with t-coils in them, but you couldn’t use them, because the t-coils weren’t programmed into a memory.

Unfortunately, this is still all to common today—so when you buy a hearing aid, you have to tell the dispenser to program the t-coils into whichever memory you want them in.

Now that the t-coil was programmed into a given memory, you had to remember which memory had the t-coils when you wanted to use them. Fortunately, some hearing aids tell you in plain English (not beeps). For example, my current aids say “t-coil” when I switch to that memory so I know I’m in the right memory.

Here’s something else you need to know. A few years ago, the hearing aid manufacturers in their great wisdom (and I use that word advisedly), decided that since t-coils were for telephones (so they thought), they would make them operate automatically. Thus, when you held a phone receiver up to your ear, your hearing aid on that side would sense the presence of the phone receiver and automatically (within 2 seconds or so) switch to t-coil mode. When you took the phone away from your ear in 2 seconds or so it would revert back to microphone mode.

This was great if you used the phone a lot, but there was a big problem. Automatic t-coils wouldn’t turn on automatically in the presence of a neckloop or a room loop. Thus, you could have hearing aids with t-coils in them—and yet you couldn’t use them for these purposes because they were exclusively turned on automatically.

As you can imagine, knowledgeable hard of hearing people made an uproar about these automatic t-coils. The upshot of it was that the manufacturers modified their software so the t-coils could be programmed into a given memory as either “automatic” or “manual”. This is the current state of t-coils today. Thus, if you want to, you can have one memory programmed for automatic t-coil mode and another memory program for manual t-coil mode so it will work in looped venues.

You can also have any memory programmed to work with both the microphone and t-coil turned on at the same time. Thus, if you had hearing aids with 4 memories, you could have them programmed such that memory 1 had microphone only, memory 2—microphone and t-coil together, memory 3—t-coil only (manual mode), and memory 4— t-coil only (automatic mode). (I’m not suggesting you have your memories programmed this way, but you could.)

One cool feature of some of the current hearing aids that “talk” to each other is that when you turn the t-coil on in one hearing aid, you can have it set up so it automatically pipes the sound to the other ear at the same time. This is useful when you are talking on the phone and need both ears in order to understand the person on the phone better.