LG UN272 - Manual (Page 158)

Safety 158
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.