Справочник Пользователя для IBM AC453A

gives you the following

options:

USA Broadcast 

USA Cable 

Japan

These are the only standards that
can be handled with an NTSC tuner. 

This brings up the Audio dialog box
to control the following audio
settings:

Volume

Mute

Bass

Treble

Balance

Changes in the volume are reflected
with a row of vertical bars at the
bottom left corner of the TV screen.
A red bar moves along the row to
indicate the current volume level.
The word Volume is displayed above
the row of bars. The volume can be
adjusted three ways:

Use the Volume button on the

remote. Pressing the top of the
button increases the volume and
pressing the bottom decreases it. 

Use the - (minus) and + (plus)

keys on the keyboard to decrease
and increase the volume,
respectively.

Select the Audio option from the

floating menu or from the
Configure 

menu in the menu

bar. This brings up a dialog box
with scroll bars for audio
adjustments. A Volume scroll bar
lets you adjust the volume level.

temporarily turns the audio

off. When mute is turned off, the
volume is restored to its original
setting. Mute can be turned on and
off as follows:

Use the Mute button on the
remote. This button toggles
mute on and off.

Use the M key on the keyboard
to turn mute on and off.

Use the Mute button in the
Audio dialog box reached the
Audio item in the floating menu
or from the Configure menu in
the menu bar.