Whenever you turn on the scanner using the switch on the volume knob, you need to set the volume level. If you put a switch in the power to the scanner, the volume will be the same as when you turned it off provided you do not touch the volume control. The BCD996P2 does not use an SD card, so there is no danger switching the power on and off. If using an AC adapter, switch the AC power so that the wall wart is not consuming power when the scanner is off. You can use an AC power strip with a switch. I had 2 BCD996XT scanners in my vehicle wired through the ignition switch. I never had any problem with the power switching on and off and the volume on both scanners was already set once they booted up.