Phonak Virto B-Titanium User Manual page 38

Note: the performance of individual hearing aids may vary
with individual cell phones. Therefore, please try the
hearing aid with your cell phone or, if you are purchasing
a new phone, be sure to try it with your hearing aid prior
to purchase. For additional guidance, please ask your
hearing care professional for the booklet entitled "hearing
aid compatibility with digital wireless cell phones".
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