As of September 2005, the FCC requires wireless Hearing X3 Review phone manufacturers to provide carriers with some cell phones with reduced RF emissions for each of the transmission technologies. Those that are considered passing (rated "good" or "excellent") for use with hearing aids set in microphone mode will be assigned a HAC rating of M3 or M4. There are also "T" ratings for telecoil coupling. Look for a cell phone with a rating of T3 or T4 for aids coupled inductively (telecoil).
M and T ratings range from 1 to 4. The higher the rating, the less likely the user will experience interference while using the cell phone. The M or T ratings should be used as a general guide when selecting a phone. You should always try out a phone before making a purchase to be sure it operates within acceptable standards. Most stores will allow hearing-aid users to try them before making a purchase. In addition, you should make sure the phone has easy-to-use volume controls.
In addition to buying the right phone, hearing aids should be designed to be resistant to RF interference. Hearing aids have the same rating scale discussed above, M1-M4 and T1-T4. Ask your audiologist for the rating on your hearing aid. The higher it is rated, the better it will work with a cell phone. If you add the rating for your hearing aid to the rating for your phone, you will get a combined rating which can guide you. A rating of 4 is considered "usable." A rating of 5 is "normal," and a rating of 6 is "excellent."