BenQ RP553K User Manual page 14

10 Parts of the display and their functions
TOUCH-USB2
15
TOUCH-USB3
16
TOUCH-USB4
17
TOUCH-USB1 must be used with HDMI 1, TOUCH-USB2 must be used with HDMI 2,
TOUCH-USB3 must be used with HDMI 3, and TOUCH-USB4 must be used with HDMI
4(MHL) or VGA.
Connects the USB cable from the display to a computer to use the
touch module.
Connects the USB cable from the display to a computer to use the
touch module.
Connects the USB cable from the display to a computer to use the
touch module.