LG G3 User Manual page 136

Safety
136
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.
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.
To enter that the Hearing Aid Compatibility rating for your phone is
maintained, secondary transmitters such as Bluetooth and WLAN
components must be disabled during a call.
Wireless Phones and Hearing Aid Accessibility
http://www.accesswireless.org/
Gallaudet University, RERC
http://tap.gallaudet.edu/Voice/
In the example to the left, 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