AT&T TL7612 - Manual (Page 19)

Adjust the corded handset audio
. Make sure that
LIFTER MODE light on
the headset base is on. Press the MODE
button on the headset base to change
the mode.
. Lift the corded handset to release
the switch hook. Place the corded
handset aside.
. Place the headset earpiece in your ear.
. Press
ON/
OFF
on the headset to listen for a dial
tone. If there is no dial tone or the dial tone is
unclear, slide the
LIFTER AUDIO ADJUST switch
on the side of the headset base from A to G until
the dial tone is clear.
Headset base and handset lifter installation