Unitron Stride B9-UP Guide D'utilisation page 32

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. "
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.
52
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.
53