be able to use a rated mobile device successfully. Trying out
the mobile device with your hearing device is the best way to
evaluate it for your personal needs.
M-Ratings: Wireless mobile devices rated M3 or M4 meet
FCC requirements and are likely to generate less interference
to hearing devices than mobile devices that are not labeled.
M4 is the better/higher of the two ratings. M-ratings refer to
enabling acoustic coupling with hearing aids that do not
operate in telecoil mode.
T-Ratings: Mobile devices rated T3 or T4 meet FCC
requirements and are likely to generate less interference to
hearing devices than mobile devices that are not labeled. T4
is the better/higher of the two ratings. T-ratings refer to
enabling inductive coupling with hearing aids operating in
Hearing devices may also be rated. Your hearing aid
manufacturer or hearing health professional may help you
find this rating. Higher ratings mean that the hearing device
is relatively immune to interference noise.
Under the current industry standard, American National
Standards Institute (ANSI) C63.19, the hearing aid and
wireless mobile device rating values are added together to
indicate how usable they are together. For example, if a
hearing aid meets the M2 level rating and the wireless
mobile device meets the M3 level rating, the sum of the two
values equals M5.
Under the standard, this should provide the hearing aid user
with normal use while using the hearing aid with the
particular wireless mobile device. A sum of 6 or more would
indicate excellent performance.
However, these are not guarantees that all users will be
satisfied. T ratings work similarly.
The HAC rating and measurement procedure are described in
the American National Standards Institute (ANSI) C63.19
Health and Safety Information