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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.
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.
FCC Hearing-Aid Compatibility
(HAC) Regulations for Wireless
Devices
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.
To enter that the Hearing Aid
Compatibility rating for your phone is
maintained, secondary transmitters such
as Bluetooth and WLAN(this phone does
not have WLAN) components must be
disabled during a call. See page 118 for
instructions to disable these components.
