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.
The HAC rating and measurement procedure are described in the
American National Standards Institute (ANSI) C63.19 standard.
M3
M3
Draft, Not Final
