Lexus OM53A24U Owner's Manual page 314

3-4. Using the hands-free phone system (for mobile phones)
■
Steering wheel switches
■
Microphone
312
Volume
During an incoming call:
Adjusts the ring tone volume
During an ongoing call:
Adjusts the receiver volume
The voice guidance volume can-
not be adjusted using this but-
ton.
Off-hook switch
Turns the hands-free system
on/starts a call
On-hook switch
Turns the hands-free system
off/ends a call/refuses a call
Talk switch
Turns the voice command
system on (press)/turns the
voice command system off
(press and hold)