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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 telecoil mode.
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.
