oticon Alta 2, Instructions For Use Manual

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56
Mobile phone
Some hearing instrument users have
reported a buzzing sound in their
hearing instrument when they are
using mobile phones, indicating that
the mobile phone and hearing
instrument may not be compatible.
The ANSI C63.19 standard deter-
mines the prediction of compatibility
between a specific hearing instrument
and a mobile phone by: adding the
numerical value of the rating for the
hearing instrument immunity to the
numerical value of the rating for the
mobile phone emissions. A sum of 4
would indicate that the combination of
wireless device and hearing instrument
is usable; a combined rating that equals
at least 5 would provide normal use;
a combined rating of 6 or greater would
indicate excellent performance.
Whereas all hearing instruments have
acoustic coupling, only the larger
instruments have the physical space
for telecoil (inductive) coupling. These
two types of coupling have different
rating scales (M1-M4 for acoustic cou-
pling and T1-T4 for telecoil coupling,
respectively) and both ratings are
therefore relevant when predicting the
compatibility of a particular hearing
instrument.
For a hearing instrument with both
acoustic coupling and telecoil coupling
with a rating of M4/T2 and with a tele-
phone rating of M3/T3), the combined
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