I bought this back in 2016. It works well as a simple battery backup BUT if you want the functionality of automating the shutdown of your computer you need the comms cable to be plugged in. Having the cable plugged in causes the device detection noise to continually go on and off (about every 10 seconds) as it "plugs and unplugs" effectively. This is a real issue when you have the audio on your computer and you hear the connect and disconnect tone while trying to listen to something. Similar to if you plug in and pull out a USB stick into a slot. I thought there was something wrong with the unit so got in touch with the manufacturer to...view more