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Mobile Phone
Some hearing aid users have reported a buzzing
sound in their hearing aid when they are using mobile
phones, indicating that the mobile phone and hearing
aid may not be compatible.
The ANSI C63.19 standard determines the prediction
of compatibility between a specific hearing aid and
a mobile phone by adding the numerical value of the
rating for the hearing aid 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 aid is usable; a
combined rating that equals 5 would provide normal
use; a combined rating of 6 or greater would indicate
excellent performance.
Whereas all hearing aids 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 coupling and T1-T4 for telecoil coupling,
respectively) and both ratings are therefore relevant
when predicting the compatibility of a particular
instrument.
