Mobile wireless service providers and device manufacturers are required to offer handsets that are compatible with (do not cause interference with) hearing aids and cochlear implants.
How does the FCC determine whether a handset is hearing aid compatible? There are two measures used. First, all digital handsets have a rating for their ability to reduce interference with hearing aids operating in acoustic mode – from M1 to M4, with M4 being the best. Handsets are also rated – from T1 to T4 – for their ability to operate with hearing aids that contain a telecoil (a tightly wrapped piece of wire that converts sounds into electromagnetic signals) and operate in inductive coupling mode. The FCC considers mobile handsets to be hearing aid compatible if they are rated at least M3 for acoustic coupling and at least T3 for inductive coupling. A specific number or percentage of the handsets sold by handset manufacturers and mobile wireless service providers must meet these ratings. These companies file Hearing Aid Compatibility Status Reports , which contain information on the hearing aid-compatible handsets that they offer.
Consumer Fact Sheet on Hearing Aid Compatibility
Hearing Aid Compatibility Status Reports 
- Reports by Handset Manufacturers 
- Reports by Service Providers 
- Filing Hearing Aid Compatibility Status Reports (FCC Form 655)
Hearing Aid Compatibility Rules  (CFR)
Orders and other FCC releases in the Hearing Aid Compatibility Proceeding (Docket No. 07-250)
Comments and other filings made in the Hearing Aid Compatibility Proceeding (Docket No. 07-250)