Hearing Aid Compatibility

Federal Communications Commission (FCC) requirements and ratings for telephones to work effectively with hearing aids and cochlear implants. HAC standards address acoustic coupling (how well the phone works with hearing aid microphones) and telecoil coupling (magnetic signal strength for T-coil users), as well as reduction of radio frequency interference that can cause buzzing in hearing devices. HAC ratings range from M1/T1 (lowest) to M4/T4 (highest compatibility).