Sony WI-C400 Help Manual page 4

Unable to connect the headset to a BLUETOOTH device with one-touch connection (NFC)
Unable to make a BLUETOOTH connection
Distorted sound
The BLUETOOTH wireless communication range is short, or the sound skips.
The headset does not operate properly.
No voice from callers
Low voice from callers
Resetting or initializing the headset
Resetting the headset
Initializing the headset to restore factory settings
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