Sonic Cheer 20, User Manual

Page: 51 / 64

51
USER GUIDE CPx BTE
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.