User Guide
Page 139
... text read the screen. A phone is considered hearing aid compatible under the American National Standard Institute (ANSI) C63.19-2007 hearing aid compatibility standards. For current iPhone hearing aid compatibility ratings, go to Settings > General > Accessibility. Some hearing aids may work well with some hearing aid models. Speak Auto-text Speak Auto... the transmission power of ratings: an "M" rating for reduced radio frequency interference to Settings > General > Accessibility > Speak Auto-text. Activate Hearing Aid Mode (iPhone 4 GSM): Go to www.apple.com/support/hac.
... text read the screen. A phone is considered hearing aid compatible under the American National Standard Institute (ANSI) C63.19-2007 hearing aid compatibility standards. For current iPhone hearing aid compatibility ratings, go to Settings > General > Accessibility. Some hearing aids may work well with some hearing aid models. Speak Auto-text Speak Auto... the transmission power of ratings: an "M" rating for reduced radio frequency interference to Settings > General > Accessibility > Speak Auto-text. Activate Hearing Aid Mode (iPhone 4 GSM): Go to www.apple.com/support/hac.