Sanyo SFX-33 Supplemental Service Manual page 6

3. OUTLINE (Page 14)
(1) Part names and functions
Rear view and left side
LINE
Monitor volume control
The switch has 3 stages.
Change the switch to the
position "H" to make louder.
Ringer volume control
The switch has 3 stages.
Change the switch to the
position "H" to make louder.
Telephone
line jack jack