@Gujite The Charge 5 does not have a microphone. From the C5 manual (https://help.fitbit.com/manuals/manual_charge_5_en_US.pdf) Answer or reject phone calls If paired to an iPhone or Android phone, Charge 5 lets you accept or reject incoming phone calls. To accept a call, tap the green phone icon on your tracker's screen. Note that you can't speak into the tracker—accepting a phone call answers the call on your nearby phone. To reject a call, tap the red phone icon to send the caller to voicemail. The caller's name appears if that person is in your contacts list; otherwise you see a phone number.
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