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Safety Guidelines
needs.
M-Ratings: Phones rated M3 or M4
meet FCC requirements and are likely
to generate less interference to hearing
devices than phones that are not labeled.
M4 is the better/higher of the two
ratings.
T-Ratings: Phones rated T3 or T4 meet
FCC requirements and are likely to
generate less interference to hearing
devices than phones that are not labeled.
T4 is the better/ higher of the two ratings.
Hearing devices may also be rated. Your
hearing device manufacturer or hearing
health professional may help you find
this rating. Higher ratings mean that the
hearing device is relatively immune to
interference noise. The hearing aid and
wireless phone rating values are then
added together. A sum of 5 is considered
acceptable for normal use. A sum of 6 is
considered for best use.
In the above example, if a hearing aid
meets the M2 level rating and the
wireless phone meets the M3 level rating,
the sum of the two values equal M5. This
should provide the hearing aid user with
“normal usage” while using their hearing
aid with the particular wireless phone.
“Normal usage” in this context is defined
as a signal quality that’s acceptable for
normal operation.
The M mark is intended to be synonymous
with the U mark. The T mark is intended
to be synonymous with the UT mark.
The M and T marks are recommended
by the Alliance for Telecommunications
Industries Solutions (ATIS). The U and UT
marks are referenced in Section 20.19
of the FCC Rules. The HAC rating and
measurement procedure are described in
the American National Standards Institute
(ANSI) C63.19 standard.
When you’re talking on a cell phone,
it’s recommended that you turn the BT
(Bluetooth) mode off for HAC.
For information about hearing aids and
digital wireless phones
When you're talking on a cell phone,
it's recommended that you turn the BT
(Bluetooth) or WLAN mode off for
HAC.