LG 49UT340H0UA Guide De Configuration Rapide page 20

External Speakers
EXTERNAL
SPEAKER OUT
or
SPEAKER OUT
LINE OUT
VOLUME
CONTROL
Control port for Speaker out
+
-
GND
RIGHT
LEFT
GND
: Depending upon model
• Use only with the 3 pole 3.5 mm stereo jack.
• Do not connect your headphones or earphones to
the port for connecting an external speaker.
12
UP
DOWN
Method of volume control port
(Depending upon model)
• Cable Spec.
GND / UP / DOWN
Each Up / Down pin
is pulled to 3.3 V with
CPU GPIO.
CPU detects transition
from 3.3 V to GND
level for volume
control.