Shanling UP4 - Call Switch; Ending Call; Refusing Call; Volume Control

During the call, quickly press the multifunctional button twice to switch
the call from the Shanling UP4 to the connected device. Repeat to
switch the call back to the Shanling UP4.
Call switch
Ending Call
Press the multifunctional button once to end the ongoing call.
Refusing Call
When a new call comes in, quickly press the multifunctional button
twice to refuse incoming call.
Volume Control
Turn the wheel clockwise to increase the volume or counterclockwise to
decrease the volume.
3. Press and hold the Mode button for three seconds to switch between
Digital Filters.
Amp Gain Mode and Digital Filter Switching
1. Press the Mode button once to display current Amp Gain mode.
2. Press the Mode button twice to switch between Amp Gain modes.