Compaq 7020 - Manual (Page 9)

Installation
Connecting the AC Power
1. Connect the power cord to the AC adapter. (See Fig. 1-6)
2. Connect the AC adapter's DC output connector to the DC
Power Jack of the monitor.
3. Connect the power cord to an AC power source.
Figure 1-6
WARNING: We recommend to install a "Surge Protector" device
between the AC Adapter and the electrical wall outlet for adding
protection against power surges to prevent the effects of sudden
voltage variations from reaching the monitor. Sudden power
surges may damage your monitor.
Compaq 7020 Flat Panel Monitor User’s Guide 1-7