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
Tmark 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 ensure that the Hearing Aid
Compatibility rating for your phone
is maintained, secondary
transmitters such as Bluetooth
components must be disabled
during a call.
T3+T2=5
119
For information about hearing aids and digital wireless phones
Wireless Phones and Hearing Aid Accessibility
http://www.accesswireless.org
FCC Hearing Aid Compatibilityand Volume Control
http://www.fcc.gov/cgb/consumerfacts/hac_wireless.html