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Health and Safety Information 89
: 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
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 is synonymous for T ratings. 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
is 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.
Other Medical Devices
If you use any other personal medical devices, consult the
manufacturer of your device to determine if it is adequately
shielded from external RF energy. Your physician may be able to
assist you in obtaining this information. Switch your phone off in
health care facilities when any regulations posted in these areas
instruct you to do so. Hospitals or health care facilities may be
using equipment that could be sensitive to external RF energy.
RF signals may affect improperly installed or inadequately
shielded electronic systems in motor vehicles. Check with the
manufacturer or its representative regarding your vehicle. You
M3 + M2 = 5
T3 + T2 = 5