G4 Monitor troubleshooting

Hello folks, we just picked up a G4 and it came with a BIG ASS monitor 23 inch or something but not a thin thing it is deep and wide.

We know that it works, it was my the computer my wife used at her job, it has power but no display. It has what looks like a USB cable comming out of the back of the monitor and we might not have it in the right hole but danged if I see an “monitor” port other than where the 15 pin monitor cable goes.

Any mac dopers out there that can help a brother out?
Thanks
ad

anyone?