We have a Zone Defense brand backup camera system that was installed by the factory that built the motor home. It is hard wired into the motor home. The power button is on the monitor. We manually turn it on and off while the iginition is on but powers off automatically when the ignition is turned off. I like to have it on at times while driving. Since we can't see out the motor home's rear window with the inside rear view mirror, I mounted the monitor where the mirror was. I also mounted a Scan-Guage-II on top of it as shown. Another feature I like about our unit is that it has built-in microphone in the backup camera in back. When backing up into a campsite, my wife stands behind the rig to spot trees, stumps, logs, boulders and such. I plainly hear her direction, very helpful when we pull in quietly after the campground is asleep. Though she'll talk quietly, I hear her loud and clear. The speaker and volume control is in the monitor itself. Actually everything is controlled on the monitor using those little white buttons on the right side.
