Sony MEX-BT4000U Mode D'emploi page 40

No ringtone.
 Adjust the volume by rotating the control dial
while receiving a call.
 Depending on the connecting device, the
ringtone may not be sent properly.
– Set "RINGTONE" to "1" (page 21).
The talker's voice volume is low.
 Adjust the volume level.
A call partner says that the volume is too low
or high.
 Adjust the volume accordingly using mic gain
adjustment (page 25).
Echo or noise occurs in phone call
conversations.
 Lower the volume.
 Set EC/NC Mode to "EC/NC-1" or "EC/NC-2"
(page 26).
 If the ambient noise other than the phone call
sound is loud, try reducing this noise.
E.g.: If a window is open and road noise, etc., is
loud, shut the window. If an air conditioner is
loud, lower the air conditioner.
The phone is not connected.
 When Bluetooth audio is played, the phone is
not connected even if you press
(handsfree).
– Connect from the phone.
The phone sound quality is poor.
 Phone sound quality depends on reception
conditions of cellular phone.
– Move your car to a place where you can
enhance the cellular phone's signal if the
reception is poor.
The volume of the connected audio device is
low (high).
 Volume level will differ depending on the
audio device.
– Adjust the volume of the connected audio
device or this unit.
No sound is heard from the Bluetooth audio
device.
 The audio device is paused.
– Cancel pause of the audio device.
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The sound skips during playback of a
Bluetooth audio device.
 Reduce the distance between the unit and the
Bluetooth audio device.
 If the Bluetooth audio device is stored in a case
which interrupts the signal, remove the audio
device from the case during use.
 Several Bluetooth devices or other devices
which emit radio waves are in use nearby.
– Turn off the other devices.
– Increase the distance from the other devices.
 The playback sound stops momentarily when
the connection between this unit and the
cellular phone is being made. This is not a
malfunction.
The connected Bluetooth audio device
cannot be controlled.
 Check that the connected Bluetooth audio
device supports AVRCP.
Some functions do not work.
 Check if the connecting device supports the
functions in question.
The name of the other party does not appear
when a call is received.
 The calling phone is not set to send the phone
number.
A call is answered unintentionally.
 The connecting phone is set to answer a call
automatically.
 "AUTO ANSWER" of this unit is set to
"ANS-1" or "ANS-2" (page 21).
Pairing failed due to time out.
 Depending on the connecting device, the time
limit for pairing may be short.
– Try completing the pairing within the time.
Bluetooth function cannot operate.
 Turn off the unit by pressing 
for more than 2 seconds, then turn the unit on
again.
No sound is output from the car speakers
during handsfree call.
 If the sound is output from the cellular phone,
set the cellular phone to output the sound from
the car speakers.