Sony XR-5450 Operating Instructions Manual page 6

During tape playback
ATA (automatic tuner activation) button ®
During radio reception
Preset number buttons @
POWER SELECT switch (located on the
bottom of the unit)
See the description about the POWER
SELECT switch in the Installation/
Connections manual.
To mute the beep sound
Press L¢_} while pressing the SEL button.
To obtain the beep sound again, press these buttons
once more