Lexus IS 250C 2014 Manual page 334

3-4. Using the hands-free phone system (for mobile phones)
Automatic volume adjustment
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When vehicle speed reaches 50 mph (80 km/h) or more, the volume automati-
cally increases. The volume returns to the previous volume setting when vehicle
speed drops to 43 mph (70 km/h) or less.
When using a voice command
■
For numbers, say a combination of single digits from zero to nine, # (pound),
 (star), and + (plus).
Say the command correctly and clearly.
Situations in which the system may not recognize your voice
■
When driving on rough roads
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When driving at high speeds
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When air is blowing out of the vents onto the microphone
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When the air conditioning fan emits a loud noise
●
Operations that cannot be performed while driving
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Operating the system with
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Registering a mobile phone to the system
●
Changing the passkey
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