H. Stephen Berger

Wireless hearing aid compatibility—handset testing requirements

The Hearing Industry and Wireless Industry has been working together since 1996 to develop a standard to resolve this issue. This paper reports on the technical challenges and the testing requirements for wireless handsets. It concludes with a brief discussion of the need for consumer education and involvement in order to achieve the optimal solution to this issue. Hearing aids operate in two modes. In their primary mode a microphone is used to sense acoustic signals. The secondary mode uses an inductive coil, known as a T‐Coil, to receive a magnetic signal which has been modulated by the audio signal. For the wireless handset, which may be used with a hearing aid, there are test requirements arising from both modes. The field strength of both the E and H field, in the area intended for use by a hearing aid must be measured and assured to be within specified parameters. For the T‐Coil mode a magnetic signal, modulated by the audio, must be assured. However, in T‐Coil mode there is also the issue of assuri...