The HDMI switches are mounted on the wall, and labelled so I know what does what, and don't have to guess any longer.Ultimately, these three switches determine what is fed into the USB capture.AV1 on the left switches between Station 201, or the set of switches on the other side of the BeebRoom.201A and 201B combine to set the output from Station 201, either proving the output to Station 201's monitor only, or providing output to both the monitor and the USB capture stick. I found that this was necessary as the monitor wouldn't display a picture without the USB capture software running on the PC so I needed to be able to split Station 201's output to provide a video feed into the monitor only.