Apple Power Macintosh 8100 Series - Manual (Page 15)

3 Plug in the monitor power cord.
Some monitor power cords are designed to plug into the back of your
computer. If you have an Apple AudioVision monitor, be sure to plug the
monitor power cord into the back of the computer, not into an outlet.
Some monitor power cords must be connected to a grounded electrical outlet,
not to the computer. Check the information that came with the monitor.
Monitor power socket Monitor power cord
5 Getting Started