Apple E2380B, E2380A HAC mode implementation

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Hearing Aid Compatibility

Version 1.0 August 6, 2011

Ben Juang Sherman Jin

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Overview

Hearing Aid Compatibility (also known as HAC mode) is a feature that requires digital wireless phones to be compatible with hearing-aids as indicated in FCC’s CFR Title 47 § 20.19. This

feature is intended to ensure that consumers with hearing disabilities have reasonable access to telecommunication services when using Apple’s iPhone 4. HAC mode feature is part of Apple’s iOS 5.0 software release for the iPhone 4. No additional

software installation is required.

Implementation

For the iPhone 4 and iOS 5.0 software release, the HAC mode feature is enabled through the use of a Hearing Aid Mode switch. For any “Out-of-the-box” device, the Hearing Aid Mode switch is set to OFF. A User can always enable this feature when required.

When the Hearing Aid Mode switch is set to ON and when the device is in a normal voice call, it will reduce the maximum transmit power by 2.5 dB in GSM operations in the 1900

MHz band. For any emergency calls, when the Hearing Aid Mode switch is set to ON, there is no reduction of the maximum transmit power.

The reduction of maximum transmit power in this band may affect the GSM cellular coverage in some areas.

The Hearing Aid Mode switch can be found in the User Interface of the iOS 5.0 software release, at the following location:

Settings --> General --> Accessibility --> Hearing Aid Mode --> On/Off

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