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The immunity of these hearing aids is at least
M4. The equipment performance measurements,
categories and system classifications are based
upon the best information available but cannot
guarantee that all users will be satisfied.
The performance of the individual hearing
aids may vary with individual mobile phones.
Therefore, please try these hearing aids with
your mobile phone or, if you are purchasing
a new phone, please be sure to try it with
your hearing aids prior to purchase.
Mobile phone compatibility rating
Some hearing aid users have reported a
buzzing sound in their hearing aids when
they are using mobile phones, indicating
that the mobile phone and hearing aids may
not be compatible. According to the ANSI
C63.19 standard (ANSI C63.19-2011 American
National Standard Methods of Measurement
of Compatibility Between Wireless
Communications Devices and Hearing Aids),
the compatibility of particular hearing aids and
a mobile phone can be predicted by adding the
rating for the hearing aid immunity to the rating
for the mobile phone emissions. For example,
the sum of the hearing aid rating of 4 (M4) and
a telephone rating of 3 (M3) would result in a
combined rating of 7. Any combined rating that
equals at least 5 would provide “normal use”; a
combined rating of 6 or greater would indicate
“excellent performance.”
