Cell Phones & Hearing Aid Compatibility
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Buzz... Whine... Hiss...
If you wear a hearing aid, or have an implanted hearing device, you already know that many hearing aid/cell phone combinations just don't work. You hear this hum, or whine, or hiss, which is very annoying. Sometimes you can't even understand the voice on the other end of the line.
This is caused by interference between your hearing aid, and the electromagnetic field and radio frequencies that your phone emits.
To resolve the interference problem, the FCC requires that manufacturers selling phones in the US make several models that are hearing aid compatible, and to rate their phones on a standard scale of compatibility.
Hearing Aid Compatibility (HAC) Ratings
Cell phones are rated M1 through M4, and T1 through T4. The M stands for the microphone rating, the T stands for the T-coil rating, 1 is for poor compatibility, 2 & 3 is medium, and 4 is the most compatible.
If you use your cell phone while your hearing aid is in 'microphone' mode, you will want to get a cell phone with an M3 or M4 rating. M4 being the better of the two.
If you use your cell phone while your hearing aid is in 't-coil' mode, you will want to get a T3 or T4 rating, with T4 being the better rating.
A phone rated T3 is also an M3 or better by design. A phone rated T4 is also an M4.
A rating of T4 gives you the most compatibility in either microphone or t-coil modes.
Hearing Aid Immunity Ratings
Hearing aids are also rated for immunity from interference, in the same M1/T1 to M4/T4 format.
For cell phone compatibility, select a hearing aid that has an immunity rating of at least 2 for whichever (microphone and/or t-coil coupling) applies. The rating should be with sales literature, in the owners manual, or available from your audiologist or hearing aid manufacturer.
Predicting Compatibility
To predict compatibility, take the rating from your cell phone, and the rating of your hearing aid, and add them together. A combined rating of 4 is considered 'usable', a combined rating of 5 is considered 'normal', and a combined rating of 6 or better is 'excellent'.
A good rating means that you will probably have a phone and hearing aid that are compatible. However, each phone and hearing aid combination is unique. Interference can also be situational (affected by distance from the cell phone tower and other factors). It's important to check the return policy and satisfaction guarantee on any phone you purchase. If you find that the compatibility in your real life situation is not good, you want to be able to return the phone at no cost to you.
Hearing Aid Compatible Phones
We have a list of hearing aid compatible cell phones, with their ratings. Phones available through our links have a 20 day customer satisfaction guarantee.
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