Using Direct Audio Input (Bluetooth) to Connect Hearing Aids to Cellular Phones

Curtis Dickinson

Copyright 2005

Direct Audio Input (DAI) is a way to connect hearing aids to Assistive Listening Devices and other devices such as recorders, MP3 players, computers, cell phones and most any other sound device that has an audio output port.

Two technologies utilizing DAI are considered either hard-wired or wireless.

Hard wired makes the connection of the hearing aid to device by plugging a cable to connect one to the other.

Wireless makes the connection via an invisible light (Infra-red) or radio waves (FM as we are familiar with it for Assistive Listening Devices and a newer FM technology called Bluetooth).

Bluetooth connections allow approximately 30 feet between the hearing aid and cellular phone. The connection is instant and interference free. A tiny microchip, with a built-in radio transceiver, is put into a module that is attached to the hearing aid via a DAI boot.

The Bluetooth technology makes the connections instantly and without a cable. It is fast and secure. This operates in a globally available frequency band, ensuring compatibility worldwide. Some assistive devices such as Phonak’s, (a hearing aid manufacturer) SmartLink provide a Bluetooth interface. This interface includes a microphone for two-way communication. It can also connect to audio sources and send that signal to your hearing aid. This means if your hearing aid is Bluetooth compatible, you can connect seamlessly to any bluetooth device worldwide.

For the rest of this column I will discuss the wireless connection called Bluetooth and how it provides a nice connection between a hearing aid and a cellular phone.

Many of the newer cell phones have Bluetooth. The Bluetooth logo is easy to recognize. (The logo is not stamped onto all cell phones or their boxes at the moment, though some are. If the phone is Bluetooth-enabled that information will be listed in the specification/feature list.)

Starkey, another hearing aid manufacturer, has designed a bluetooth module that will fit most Behind-the-Ear style hearing aids that accepts a standard 3-prong Euro plug. With this module you can make the connection to a cell phone. You can talk back and forth and enjoy excellent sound with no interference.

This module designed by Starkey is called ELI (Ear Level Instrument). It weighs 4 grams, and becomes an extension of your BTE hearing aid, powered by a rechargeable battery. It is attached to the hearing aid via a DAI boot, which can be purchased where you purchased your hearing aids.

ELI provides a two-way communication signal between your (bluetooth-enabled) cell phone and your hearing aid so that they will “talk” to each other. This provides an interference-free and hands-free compatibility. Instant connection.

If your current hearing aid does not have a connection for the Euro plug you may be able to have it modified. Or if you love using the telecoils in your hearing aids Starkey has designed a neckloop with the Bluetooth module.

A disadvantage of Bluetooth is that it may have a fast drain on battery life. But be sure this will be overcome in future Bluetooth designs. However, the ELI and the SmartLink themselves both use rechargeable batteries. A charger is included with these systems.

Whatever you decide for hearing aids, always remember that two hearing aids are better than one; that telecoils and DAI options are great and that if you don’t help yourself, who will?

DO-IT-YOURSELF-Bluetooth headset: Here is a great website that shows you how to make your own Bluetooth headset to work with your hearing aid. It is written by a man with inside knowledge at the laboratory.

PHONAKS' SmartLink Bluetooth interface:

STARKEY’S ELI: This website includes a list of Bluetooth cellular phones along with information about the ELI:

CONTACT: Curtis Dickinson can be contacted at

The PHONAK SmartLink and the Starkey ELI and Hearing Aid Boots can be purchased from the Hearing Loss Help Co at


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