Dell U2422H 23.8" 16:9 IPS Monitor - Manual (Page 45)

Setting Up the Monitor
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NOTE: When the monitor and PC are both at power OFF state at the
first time, it is recommended that you turn ON the monitor first, then
connect the USB-C cable from the PC to the monitor.
NOTE: You can power the Optiplex 7090/3090 Ultra platform using its
DC adaptor jack. Alternatively, you can power the Optiplex 7090/3090
Ultra platform using the monitor’s USB-C cable via Power Delivery
(PD); please set USB-C Charging
90W to On in Off Mode.
Using DPBS Function
When you connect the USB-C cable, the Monitor/PC state is as follows:
When you press the monitor power button or PC power button, the Monitor/PC
state is as follows: