There has been much buzz in the media recently regarding “Made for iPhone” hearing aids, much of it generated by ReSound’s participation in the Consumer Electronics Show in Las Vegas, where ReSound LiNX was introduced to a wider audience than we typically reach in the hearing aid industry. While ReSound LiNX is a high performance hearing instrument incorporating Surround Sound by ReSound technologies and wireless connectivity based on the proprietary ReSound 2.4 GHz digital wireless system, it has been getting attention mostly as the first hearing aid to allow direct connection to Apple devices. As we prepare for ReSound LiNX to become broadly available, it seems like a good time to review and hopefully clarify different ways that hearing aid wearers can interact with iPhone devices. Although other exciting audio streaming and data exchange-based features are possible with ReSound LiNX, the current discussion is limited to phone usage.
Use the phone with no special accessories and no digital wireless connections by holding the phone up to your hearing instrument microphone (acoustic coupling) or setting your hearing instrument to telecoil (inductive coupling).
The iPhone 4 and iPhone 5 are compatible with cell phones in accordance with FCC requirements. Depending on the particular model, they either have M3 or M4 ratings for acoustic coupling, and T4 ratings for inductive coupling. The rating may also be dependent on whether you have activated “Hearing Aid Mode”.
“Hearing Aid Mode” can be activated by choosing “Hearing Aid” in the “Hearing” section of the iPhone device’s “Accessibility” menu. If you have an iPhone 4, Hearing Aid Mode will reduce transmission power of the cellular radio and can result in better sound quality for acoustic coupling. If you have an iPhone 5, iPhone 5s or iPhone 5c, Hearing Aid Mode modifies the acoustic settings of the phone to improve sound quality for inductive coupling. Note that Hearing Aid Mode does not result in any kind of data exchange or streaming to the hearing aids, and is appropriate to use with any brand, style or model of hearing aid. It is not related to “Made for iPhone” functionality.
Receive the phone signal via a wireless phone accessory or streamer that connects to the phone via Bluetooth. Apart from the hands-free convenience, a great advantage of this in terms of hearing is that the signal is received in both hearing aids if the individual is bilaterally fit. All hearing instrument manufacturers with digital wireless systems have some kind of device that will do this. For ReSound, this is the Phone Clip+. The accessory or streamer accepts the Bluetooth signal from the phone and converts it to the appropriate wireless signal that can be received by the hearing aids. The Phone Clip+ converts the standard Bluetooth signal to the ReSound proprietary 2.4 GHz digital wireless signal for transmission to the hearing aids. In addition, the accessory must be worn or placed such that a built-in microphone in the accessory can pick up the voice of the hearing aid wearer, convert it to a Bluetooth signal, and transmit it back to the cell phone.
Pairing and connection between the Phone Clip+ (or other manufacturer’s phone accessory/streamer) is handled in the Bluetooth menu of the iPhone.
Receive the phone signal directly to the hearing instruments with no wireless phone accessory or streamer. This describes what a Made for iPhone hearing instrument can do. Apple has developed a proprietary audio streaming protocol in the 2.4 GHz band that the hearing instrument must be able to tap into in order to receive the phone signal directly. That means that the hearing instrument must have a 2.4 GHz radio, and must also have adopted the communication protocol developed by Apple. iPhone 5, iPhone 5s and iPhone 5c with a minimum iOS version 7.x can communicate with Made for iPhone hearing instruments, of which ReSound LiNX is the first. The hearing aid wearer speaks into the phone itself, so the phone can either be held normally or just placed nearby so that it can pick up the user’s voice. As of today, no cell phone manufacturers other than Apple have made this type of functionality available for hearing instrument manufacturers to connect to.
Pairing and connection between ReSound LiNX and the iPhone is handled in the same “Hearing Aids” screen as the Hearing Aid Mode. When discovered by the iPhone, the ReSound LiNX hearing aids appear in this screen under “Devices”, as shown below. The hearing instrument wearer’s first name as stored in the hearing instruments is shown along with the brand and model of instrument. In this example, a test client named “Aventa” was used, so the ReSound LiNX devices are identified as “Aventa’s Hearing Aids”.
©2014, Apple and iPhone are trademarks of Apple Inc., registered in the U.S. and other countries.
Bluetooth is a trademark of Bluetooth SIG, Inc.
 Other Apple devices are compatible with Made for iPhone hearing instruments, but we are limiting this discussion to phone use for the sake of simplicity.