HP Slate 21 Pro All-in-One User Manual page 17

4. If you want to use a keyboard and/or mouse, connect the keyboard and mouse to the USB ports
on the rear panel of the all-in-one after powering it on.
NOTE: You must power on the all-in-one before connecting the keyboard and mouse.
To use the keyboard and mouse in HDMI mode, they must be plugged into the USB ports on the
rear panel.
5. If you want to attach an HDMI device, connect an HDMI cable to the HDMI port on the rear panel
of the all-in-one (1), and then to an HDMI device (2).
NOTE: To use the HDMI device, you must switch to HDMI mode.
Connecting the cables 9