If you wear hearing aids, you may experience audible interference when using a digital wireless telephone due to radio frequency (RF) emissions from the phone, regardless of whether the microphone or telecoil settings on the hearing aids are used.
As a result, when you hold a cell phone (or other wireless device) up to your hearing aid, you often hear annoying interference. This interference can make understanding speech difficult, communication over cell phones annoying and—in the most severe cases—render the phone completely unusable to the hearing aid wearer.
Fortunately, new rules adopted by the Federal Communications Commission (FCC) require cell phone makers and service providers to make phones work better for people using hearing aids and cochlear implants. These rules require:
• Less static
• Less interference
• Better telecoil connections
The FCC defines Hearing Aid Compatibility (HAC) for cell phones in terms of radio-frequency (RF) emissions—the "M" (microphone) rating, and the "T" (telecoil) rating. The rating scale ranges from 1 to 4. The higher the “M” rating, the less likely the hearing aid user will experience interference when the hearing aid is set in the microphone mode while using the cell phone. A higher M number means the phone will sound clearer.
If you have a hearing aid or cochlear implant with a telecoil, look for a phone that has a telecoil (T) rating of T3 or T4. The higher the “T” rating, the less likely the hearing aid user will experience interference when the hearing aid is set in the telecoil mode while using the cell phone. A higher T rating will make your conversations clearer.
Thus, if you use your cell phone while wearing your hearing aids in the microphone ("M") mode, look for one that is rated M3 or M4. If you use your cell phone while wearing your hearing aids in t-coil ("T") mode, look for a phone that is rated T3 or T4. (T4 is better.) The higher the rating, the less likely it is that you will experience interference.