There is a port for an external power source but its connected straight to the 5V line Therefore if you should externally power, we recommend prying open the situation and cutting the pink 5V line with the USB link. https://nicolasonov481471.activosblog.com/29690543/a-simple-key-for-iogear-2-port-full-hd-kvm-switch-with-hdmi-and-usb-unveiled