Placing a telephone handset up to the ear where a BTE (Behind the Ear) hearing aid is used results in a poor acoustic seal and it usually causes the hearing aid to go into oscillation. This is because most of us who need the increased power of a BTE hearing aid operate the hearing aid at max power... the point just below the start of oscillation. Anything that is brought up in the vicinity of the earmold and hearing aid shortens the acoustic feedback path and oscillation starts. The solution to this problem is to use an electronic coupling from the telephone handset to the hearing aid. This electronic coupling takes the form of a transmitting coil inside the telephone handset and a receiving coil inside the hearing aid. We call these coils "telecoils". This is the most common way BTE hearing aids are used with telephones, and it is a very effective way for many people. The HAC (Hearing Aid Compatibility) Act specified that all wireline phones purchased in the United States after 1991 must have a telecoil.
However, some people report poor results with this method and it can be caused by a weak telecoil in the telephone or a weak telecoil in the hearing aid, or both. If a person wants to use this method but has poor results with it, I can think of three ways to improve it:
A neckloop is an induction coupling device that is worn around the neck, like a necklace. It has a cable and plug to connect it to amplifiers, radios, tape players, etc. A hearing aid user has to have hearing aids with the telecoil feature to use a neckloop. The neckloop generates a strong electromagnetic field all around the head. Both hearing aids, if a person uses two hearing aids, can pick up the electromagnetic radiation with their telecoils. Listening with both ears is a definite advantage for many people because it really appears that listening with two ears is much better than twice as good, at least for me. I use both hearing aids in all other listening situations - so why not on the phone? It's just that traditionally, phones are made to hold up to one ear. Being a person with severe to profound hearing loss, I have to break with tradition and say that does not give me satisfactory access.
People who have only one hearing aid may find that some of the solutions below result in better communication because the signal is better or placement of the handset to the sensitive spot on a hearing aid is not necessary. Also people whose hearing aids have weak telecoils should find that these solutions make up for the hearing aid's lack of sensitivity, because it is possible to drive the neckloop at very high signal levels.
I welcome comments to anything in this article that points out the need for better explanation or to correct errors. Mention of a product does not necessarily imply endorsement or failure to mention a product does not mean a lack of endorsement. It is impossible for me to personally test all products available. Ron Vickery
Many people cannot use a phone even with the solutions below and they have to use a "Text Telephone". At one time, "text telephone" was abbreviated "TT", but now most people like to call them "TTY" or "TDD". Even people who can use a phone quite often find Email with a computer or using a TTY to be much simpler. Ordinary use of a TTY is very easy, but being what POTS (Plain Old Telephone Service) is, there are some difficulties that arise concerning call handling and answering machines. I refer the reader to an excellent article by Dana Mulvany that covers TTY Strategies.
Telephone pickup coil ========>Amplifier ========>Neckloop
The pickup is available for about $3-$4 at popular electronics stores. The coil is contained inside a plastic case with a suction cup on one end and a cable terminated with a 1/8" two-conductor plug on the other end. The amplifier can be a popular ALD (Assistive Listening Device) such as a PocketTalker, Sound Wizard, or homemade. These devices and neckloops are available from ALD dealers.
This method works fairly well on phones that have a HAC (Hearing Aid Compatible) handset. The suction cup pickup is attached to a smooth surface of the handset close to the earpiece. It works better on the old POTs (Plain Old Telephone) when the pickup is placed inside the POT next to the line transformer. It is bad about picking up hum if there is anything close by such as a computer monitor or fluorescent light. When used on a handset, this method often generates electronic feedback, because the pickup receives signal from the neckloop. To avoid feedback, the gain on the amplifier must be kept low, and/or the handset must be held in a funny way to separate the pickup from the neckloop. ---7/28/98 RHV
Oticon TA80 =====>Amplifier =======>Neckloop
I have written a separate page about this arrangement because an ordinary patch cable does not work. The page gives details about constructing a patch cable with a load resistor.
This method is much better than #1 above because the TA80 receives sound, rather than electromagnetic energy, from the telephone. It is better for two reasons: (a) It can be used on any phone that produces sound, so the phone does not have to be HAC, or it could have weak HAC. It may not be convenient to use it on all phones, depending on how a phone is physically designed. (b) It avoids the electronic feedback problem that is inherent with #1 above. ---7/28/98 RHV
Handset coupler =======>Amplifier ==========>Neckloop
Handset coupler =======>Wide Area Loop Driver ==========>Room Loop
Handset coupler =======>DAI Cable =========>Hearing Aid
Handset coupler =======>Patch Cable ========>Cochlear Implant
Handset coupler with built-in Amplifier ===========>Neckloop
A handset coupler is a device that goes between the deskset of a telephone and the handset. It has a modular plug on a cable that plugs into the deskset. The cable from the handset plugs into it. The signal to and from the handset is not altered in any way, so people with normal hearing can use the handset just as if the coupler is not there. The coupler taps off the signal to the earpiece and routes it to a cable or jack where an ordinary amplifier is connected. Some handset couplers have an amplifier built in, so only a neckloop is required.
This arrangement works very well on analog residential phones and on most digital phones too because the signal at the handset plug is just ordinary analog audio. By "digital", I mean phones used in businesses that have a centralized digital PBX. It does not work on one-piece phones, cordless phones, cell phones, or pay phones.
Examples of handset couplers: The Williams Sound "Telelink" and the AUX Telephone coupler from Centrum Sound. There may be others. Also the "Speech Adjust-a-Tone" unit appears to be a handset coupler with a built-in amplifier. It has equalization controls and a headphone jack, so I assume a neckloop can be plugged into the headphone jack. (But I don't know for sure.)
Examples of "Amplifiers" in the drawings above include SoundWizard, PocketTalker, Radio Shack mini amp, plus some others, and homemade.
By a "wide area loop driver", I mean any power amplifier that
has sufficient power to drive a room size or bigger induction loop. I need
to research this further and expand this description, but in general, bigger
looped areas require more amplifier power. A ten watt amplifier will probably
drive a chair pad size loop, and a 30 watt amplifier will drive a 90 foot
loop. The loop must be impedance matched to the amplifier for best results,
and this usually means the amplifier has to have a 4 ohm or lower impedance
tap and be ruggedly designed for continuous duty. There is a SHHH publication
that gives design specs for loop systems. There are some amplifiers especially
designed for loop operation such as the Oticon Minicom and Oval Window
Microloop II. - - - 8/8/98 RHV
Telephone with an output jack =======>Amplifier ========>Neckloop
Telephone with a built-in neckloop driver ==========>Neckloop
This item is almost a repeat of the item above, except that a handset
coupler is not needed. I can't give any definite examples of phones with
these features but I will keep looking and update this item. I have seen
cordless phones and cell phones with output connectors, but I have not
seen an ordinary wireline desk type phone with connectors or neckloop output.
Phone Line Tap ========>Amplifier ========>Neckloop
Phone Line Tap =========>Wide Area Loop Driver
Computers with telephony features ============> Neckloop
Computers with telephony features ============> Wide area Loop Driver
Computers with telephony features ============> Speaker Phone Function
Many Personal Computers with multimedia features have their sound card and modem configured to serve as a voice phone. Some of the multimedia powered speakers have a headphone output jack, so a neckloop can be plugged into the headphone jack. The jack is usually a three conductor jack (stereo) so a stereo to mono adapter should be used or a neckloop with a three conductor plug should used. A two conductor plug will short out one channel of the jack and it may damage the amplifier in the powered speaker. I have not found very satisfactorily results with this method because the output level of the headphone jack is not enough to drive my neckloop. Some brands of powered speakers may have a higher level on the headphone jack. Note: a "powered speaker" is a speaker in an enclosure that also contains the power amplifier neccessary to drive the speaker. Ordinary speakers like used on a home stereo are just speakers in an enclosure... they do not have the power amplifier. The power amplifier in this case is integrated into the stereo sound system.
Additionally, the output on the sound card is a "line level" output, so any ALD or external sound system that accepts line level can be plugged in directly to the sound card, bypassing the multi-media speakers altogether. One would have to get matching plugs or adapters to make this connection, observing the same precaution noted above about not plugging in a two conductor plug into a three conductor jack. If you want the flexibility to use either your external device or the powered speakers, you would have to devise a switching arrangement.
I have found very satisfactory results using my current computer system with just the powered speakers that came with it. Included with the system is a headset mike that has very good noise suppression. With this mike, I can turn the volume up on the speakers to a level loud enough for my hearing aids to hear it, and at the same time, not cause feedback, and it is full duplex. Quite amazing. I could not do this with my former system satisfactorily. The key to the way it works is that the mike has to be very close to my mouth, and it does not pick up sound from other sources. If it did pick up the sound from the speakers, it would produce feedback. There is a level where it does produce feedback, but that level is higher than I need to be able to hear, so I can keep it below this level. Using this method goes full circle with me. The first attempt I made at hearing with both ears was to use a speakerphone. The quality of sound with the multimedia speakers is much better than the old speakerphones I used to use. One shortcoming with speakerphones, however is that they do not allow privacy... the sound is so high up the entire neighborhood can hear it!
Another benefit to using a personal computer with telephony is that
they usually incorporate an answering machine function. If you use the
computer as your phone and it works well for you, then chances are you
will be able to use the answering machine too, listening with any of the
three methods above.
--- 10/13/98 RHV