Hearing Aid Compatibility Technical Bulletin
By Mike Sandman
New home and business phones
sold in the US have been Hearing Aid Compatible since the 1980's.
That's nice, but nobody really knows what Hearing aid Compatible
mean that every person with hearing problems will be able to hear from
every phone, even if it's Hearing Aid Compatible.
There are two ways for
modern hearing aids to pick up sounds:
Through an internal
Through a T-Coil (Telephone Coil) that hears sounds
inductively by magnetism.
Hearing Aid Compatible
in relation to phones simply means that the receiver in the handset not only plays the audio
of the conversation like a speaker in a radio (into your ear), but it
has a magnetic signal that you can't hear in
your ear as well.
The magnetic signal can be
picked up with a coil of wire attached to an amplifier that
turns the magnetic signal into an electrical signal, that can be sent to
a hearing aid or even a tape recorder. There used to be a little suction
cup gizmo that you would stick on a handset and then plug into a tape
recorder to record a conversation, which used magnetic induction just
like a T-Coil.
The T-Coil in a hearing aid
is a loop of wire that picks up the magnetic signal (through induction).
The real benefit is that the hearing aid wearer turns off the
microphone in the hearing aid while they're using the T-Coil, which
eliminates the annoying squeal every hearing aid without a
T-Coil makes - that the hearing aid wearer often can't hear.
The squeal is simply
feedback, like you'd hear if you stood too close to a public address
speaker while holding a microphone. When the user of a hearing aid without
a T-Coil turns up the hearing aid's volume, the microphone in the hearing aid can hear the
speaker in the hearing aid that much louder, so feedback occurs.
When the user of a hearing
aid with a T-Coil flips the switch from M (for Microphone) to T (for
T-Coil), the microphone in the hearing aid is turned off entirely, and
the only "sounds" the hearing aid can hear are the magnetic
signals coming from the receiver in the handset. Because the microphone
is shut off, feedback can't normally occur (unless there's feedback
between the telephone's handset microphone, and the hearing aid).
These are the controlling facts
of Hearing Aid Compatibility:
If the hearing aid
doesn't have a T-Coil, it won't work properly with a telephone
handset that's Hearing Aid Compatible.
If the telephone handset
receiver doesn't put out enough of a magnetic signal, it's not
Hearing Aid Compatible, and it won't work correctly with a hearing
aid with a T-Coil.
The history of Hearing
Aid Compatibility is interesting. For many years, all of the phones
rented out by Bell Telephone Companies were Hearing Aid Compatible. The
way the receiver element in the handset was made it put out a large
magnetic signal that hearing aid manufacturers took advantage of to
eliminate the feedback or squeal.
After the Carterphone
decision in 1968 which allowed you to connect your own phones to Bell
phone lines, Japan started selling phones in the US that were cheaper
than Bell phones. Some of the receivers in the Japanese handsets didn't
have the magnetic signal, which was taken for granted by that time in
the US, so hearing aids didn't work with those Japanese phones.
In the late 1970's, the FCC
made a rule that all phones being sold in the US had to have Hearing Aid
Compatible receivers in their handsets by the early 1980's. The Japanese phone manufacturers
simply added a coil to the receivers that didn't already meet the US
specs, and everything was back to where it was when all of the phones
were Bell phones - as far as hearing aids we concerned.
In the early 2000's, the FCC
made a rule that all of the phones sold in the US should be
"amplified." That meant that there had to be a volume button
or wheel to turn up the volume in the handset. In addition if the
volume could be set so it was very loud, the phone was supposed to return to
normal volume when it was hung-up so the next person using the phone didn't have their hearing damaged.
None of this
makes a difference whether the handset is "Hearing Aid Compatible."
Hearing Aid Compatible doesn't mean the handset is amplified. It only
means the handset puts out enough magnetic signal to be picked up by a
T-Coil in a hearing aid - not picked up the microphone.
This is confusing. If a telephone's
handset does contain a Hearing Aid Compatible receiver, and the phone or
handset has an amplifier, the magnetic signal from the receiver will be
stronger than from a non-amplified handset. An amplified handset isn't necessary to use the T-Coil in a
Even though all phones have
been Hearing Aid Compatible since the 1980's, hardly anybody knows what
Hearing Aid Compatibility really means...
simply means that the receiver in the handset
puts out a magnetic
signal for T-Coils, in addition to the audio signal.
The confusing part is that the
hearing aid has to be made with the T-Coil to be able to work
with a Hearing Aid Compatible phone. If it doesn't have a T-Coil, the
hearing aid can only use the built-in microphone that's also used for
normal conversations, and it will almost assuredly squeal and it will be
difficult to hear on a telephone handset.
Many of the
companies selling hearing aids don't educate their customers. If their
customer doesn't understand how to use their hearing aid or its
capabilities, the customer is definitely not making an informed purchase
and there's going to be bad blood down the road. Sometimes the hearing
aid dealer blames the hearing aid's limitations on the phone, which
usually isn't the case.
It would seem logical that when someone gets a new hearing aid
they bring one or more of their home phones with them to the hearing aid
store to have the salesman show them how the new hearing aid works with
their phones. I would do it if I was buying an expensive hearing aid
that the salesman told me worked with phones. If you don't bring in the
phones it's just constant finger pointing and nothing gets
resolved. Many hearing aid salesman just hope that their customer gives
up so he can go enjoy his commission. They don't seem to get that they'd
get a lot more commissions by having happy customers who referred others
If the hearing aid has a
T-Coil, it might have a little switch that the user can move to choose
between the microphone and T-Coil. With the constant miniaturization of
hearing aids, it's become difficult to put a physical switch on a tiny
device that a
user can actually move with a finger (it's easier with behind-the-ear
hearing aids because they're bigger and easier to get to). Some hearing
aids come with a remote control that lets the user manually turn on the
T-Coil. That's the hot setup.
When hearing aids really
got tiny and in the ear, the next innovation was the automatic
There is NO Standard for Operating
the T-Coil Automatically
when you put a Handset to your Ear
It turns out that most
receivers in handsets put out a permanent magnetic field
in addition to the magnetic signal (audio) that's picked up by the T-Coil. Most
handset receivers are a basically a tiny (dynamic) speaker with a
permanent magnet and a cone (diaphragm).
Hearing aid manufacturers
decided to make use of that permanent magnetic field to turn on the
T-Coil automatically when a telephone handset was put to
the ear (near the
hearing aid). When the wearer holds the handset to the ear that
the hearing aid is in, a little magnetic reed switch in the hearing aid is activated by the
permanent magnetic field, and the T-Coil is switched on automatically
(switching off or turning down the microphone at the same time).
That's a nice idea except
that there is no standard for how strong the permanent magnetic field is
in a handset.
It could be none, it could be a little, or it could be a
lot. The strength of the permanent magnetic field has no relation to
either the audio coming out of the handset receiver, or the magnetic
signal that the T-Coil couples to. It's just how the receiver
manufacturer decided to design their receiver - and it's likely that
when the handset for the phone was designed nobody gave any thought to someone using the
permanent magnetic field to turn on the T-Coil
automatically in a hearing aid.
Hearing aid manufacturers
picked some arbitrary amount of magnetism that's necessary to activate
the really tiny reed relay in the tiny hearing aid. That means the hearing aid may
or may not activate the T-Coil when the handset is held up to a
particular make / model in-the-ear hearing aid. If it doesn't, there's probably no
manual switch for the wearer to move unless the hearing aid has a remote
control, so the hearing aid wearer just
can't use a phone who's handset doesn't put out enough of a
permanent magnetic field (without taping a magnet to the handset, which
is described farther down the page).
I'd seriously suggest that
you get a remote control for the next hearing aid you buy that lets you
control the volume, has a tone control - which is like a mini-equalizer
built-into the remote, and a control that lets you turn on the T-Coil
manually instead of needing a magnet next to your ear. If you didn't get
one with your hearing aid, you might want to enquire whether one is
available for more money?
A benefit of being able to
turn the T-Coil on manually means you can use any Hearing
Aid Compatible handset from any phone no matter how much of a magnetic
field it puts out (by manually switching on the T-Coil), and
you can use a neckloop.
A neckloop is a wire that
you wear around your neck that has a small audio plug (usually 3.5mm,
2.5mm, or both), that after you turn on the T-Coil in your hearing aid
allows you to get audio from anything that has an earphone jack - like a
computer, some phones, some telephone amplifiers, TVs and audio / MP3
When you use a neckloop
there's nothing sitting next to the hearing aid to turn on the T-Coil
If there is no manual switch on the hearing aid to turn
on the T-Coil (there probably isn't one on a modern tiny hearing aid),
the remote is the only way to turn off the mic and turn on the T-Coil
which - lets you "hear" from the neckloop inductively, with no
background noise since the mic in the hearing aid is turned off
or down when the T-Coil is turned on.
If you can manually turn on
the T-Coil in your hearing aid, another benefit you get if you wear two
hearing aids is that you'll often get the same audio in both
ears. It won't be true stereo, but having the sound of your phone coming
through both hearing aids at the same time, with the mic turned off so
you don't get background noise, can make it substantially easier to
understand the person on the other end of the phone.
When you use a neckloop with
a phone, you still have to talk into the handset for the phone.
The audio from the handset receiver will be picked up by the neckloop
when you turn on the T-coil manually. Then, you don't have to hold the
handset right next to your ear but you still have to talk into the
mouthpiece for the person at the other end to hear you.
Andrew, a hearing aid specialist at the Loud & Clear
Hearing Aid shop in Berkeley CA, mentioned to me that
there's a push in the US to install In-building Hearing
Loops at public venues like churches and movie theatres,
and even in people's homes. The T-Coil in a hearing aid will
pick up the sound from the loop installed in the room's
ceiling, and the wearer will be able to hear without using
the microphone in the hearing aid... cutting out background
noise and squealing. For more information
checkout the non-profit HearingLoop.org website:
Getting a Hearing Aid to Turn on
the T-Coil Automatically
when the Handset is Placed to your Ear
In the past almost all
handsets looked the same. In the last ten years almost every handset
looks different - often a really strange shape. A lot of those handsets
are sealed so they can't be taken apart. If the handset can't be opened it's
difficult to replace the receiver in a handset with one that puts out a
stronger permanent magnetic field.
In many cases, another type of handset with a receiver with a stronger magnetic field won't
fit on the phone itself (won't hang-up).
The bottom line is that if a
hearing aid wearer has an automatic T-Coil switch, and the wearer is
trying to use a phone without enough of a permanent magnetic field to
turn on the automatic T-Coil switch, the wearer won't be able to use the
phone with the T-Coil even though the handset is Hearing aid Compatible.
A symptom of the automatic
T-Coil switch not working with a particular phone is squeal. If the
wearer is sure the hearing aid has a T-Coil and has an automatic
switch, you can tell it's not being activated if there's a squeal when the
hearing aid volume is turned up and the handset is held to the ear. That
means the microphone in the hearing aid is still live, and there's squeal
(feedback). The squeal will increase as you turn up the volume in your hearing
The microphone in the hearing aid
should be turned off or way down when the T-Coil is activated (that's what
prevents the squeal). A test you can do to see if the T-Coil is activated is
using your finger to scratch on the hearing aid. If the scratching always
sounds the same (loud), even when the T-Coil should be activated, the T-Coil probably
isn't activated. If the volume of the scratching is lower or gone when the handset is
next to your hearing aid, the T-Coil is activated.
The fix for a handset that won't
activate a hearing aid is to get a handset
with a receiver with a stronger permanent magnetic field. That's either
done by putting a different type of handset with the same electrical
characteristics - but a stronger permanent magnetic field (like from a
different manufacturer) on the phone, or replacing the receiver element
in the existing handset with one with a stronger permanent magnetic
field. See a solution that Phonak has for their automatic T-Coil,
taping a magnet to the handset, farther down the page.
Since it's possible that a
handset simply has a defective receiver element, the quickest test is
just to swap handsets with the handset on another phone to
see if it works with that handset. If it doesn't work, the hearing aid wearer is either
going to have to get a hearing aid with a manual T-Coil switch (or
the handset or receiver on the phone, tape a magnet to the handset, or use an entirely different brand
In some cases, it may be
possible to epoxy a small powerful magnet inside near the receiver of a handset
to activate the automatic T-Coil switch. These tiny powerful magnets are
often called "rare earth magnets." If the handset can be
opened, it may be possible to hot glue or epoxy the magnet inside, near the
My personal opinion is that
if the automatic T-Coil switch doesn't work it's not a shortcoming of the
phone, but of the design of the hearing aid.
Cell and Cordless Phones?
While this applies to corded
(and some cordless?) home or business phones, it doesn't apply to cell
phones. Each cellular provider should have a couple of
models of phones that are Hearing Aid Compatible, but they aren't
required to make all of the models Hearing Aid Compatible. If the phone
you like doesn't work with your hearing aid, you don't have any recourse
other than to use a different cell phone that does work.
Keep in mind that while a
couple of models of cell phones are supposed to be Hearing Aid
Compatible, that doesn't mean those phones will work with an automatic
T-Coil switch. There are no FCC rules that say anything about an
automatic T-Coil switch, so you may need a hearing aid with a manual T/M
switch or remote control to be able to use a particular model phone. Or
maybe tape a magnet to the phone near the receiver hole?
What kind of Home Phone Should I Buy?
While Clarity brand
amplified phones seem to be the most popular, I keep getting calls about
how they don't work well. I found that out myself by buying them for my
Mother and Uncle.
I sent my Uncle a Geemarc
phone I found on Amazon. He said it worked better than the half dozen or
so Clarity phones he has laying around (Geemarc
Ampli600 Single Line Phone). You can click on the Amazon link below and
to the right to see the phone.
It also has an
emergency notification dongle he can carry around the house, that doesn't require
He said that his neckloop works pretty well using the jack for the neck loop on that
The Geemarc also has a
pretty loud speakerphone. Speakerphones are difficult to make loud
enough for a hard of hearing person to use since when the speaker is
turned up very loud, the mic will hear the speaker and the phone may
squeal (feedback) or cut in and out from the speakerphone's voice
a speakerphone, the user can just use their regular hearing aids to
talk on the phone, without using the handset and the T-Coil. It doesn't
work for everybody, and definitely doesn't work on a cheap Wal-Mart
type speakerphone. In an office a loud speakerphone would really annoy
all the other workers, so that's not a good solution.
I got my Uncle an old AT&T
4B office type speakerphone (hasn't been make in over 20 years) which
has a very loud speaker. He said he can hear that pretty well. They are
difficult to find (used) and difficult to install, so I wouldn't recommend
that except for an old phone man who knows how to install it.
Our In-Line Handset Amplifier works with
nearly any phone with a dial in the base including business phones and VoIP
Just slide the volume control up
and down to change the volume...
Call 630-980-7710 to
In-Line Handset Amplifier
Includes 9V Battery
that lasts around a year
Number: XMT9A $27.95
Model with AC Power Cube
(doesn't need a battery, but you need an outlet near the desk)
Number: XMT9C $35.95
Phone Orders at 630-980-7710, or this item can
be ordered Online with Priority Mail shipping:
It takes under a minute to
plug into just about any phone...
Just unplug the handset cord, plug
the In-Line Amplifier back into that jack, and plug the
handset cord into the other side of the In-Line Amplifier. Move the
convenient slide volume
control to adjust the volume (it raises the volume by 18db).
We've been selling this
Amplifier for 15 years and it works! Others we found don't. Callers constantly tell
us that they've tried amplifiers from electronics or drug stores but they sound
terrible or don't work at all.
This device works on business and
VoIP type phones, but not on dial-in-the-handset (Trimline) type phones, not on
cordless or cellular phones, and not RCA and GE brand phones.
Phonak Automatic T-Coil Activation
My uncle has a bunch of
hearing aids, some as much as $5,000, that don't work. The hearing aid
dealers abandoned him after he paid them. He finally asked the VA for
help. They got him a sophisticated Phonak brand hearing aid (www.phonak.com)
with a small remote control that seems to have helped.
He mentioned that in the
instruction book he got with the hearing aid, it explained that he could
get a small magnet that could be attached to a handset that won't turn
on the automatic T-Coil in his hearing aid:
The handset that's pictured
is a T-Style handset for a Northern Telecom business phone - that's
sealed shut. We make the same handset with screws, so we can open the
handset and put in a receiver with more magnetism. If you don't have
that option, this little magnetic disk is a great idea!
Note that is has to be
glued/taped to the handset in the proper position to be close to the
reed switch in the hearing aid, and it has to be flipped to the correct
polarity, or it will pop right back off the handset because the magnet
in the handset is repelling the little magnet instead of attracting it.
have a limited number of T-Coil
(size may vary)
PAP4B - Limit 2 per order -
Phone Orders at 630-980-7710, or this item can
be ordered Online with Priority Mail shipping:
This is pretty scary...
It turns out that when my Uncle he
got this fancy hearing aid the VA didn't bother to activate the T-Coil when they
setup the hearing aid for him.
He only found out when I kept
sending him stuff to test that didn't work right. He finally went to the VA two
years later when he got them to turn on the T-Coil which now works in both
hearing aids when he holds the handset to his ear.
That seems to have made all the
difference in the world for his being able to talk on the phone, which was a
real struggle before!