A KVM switch has a switching device, a first computer video interface, a second computer video interface, an image processing unit, and at least one console video interface. The switching device is arranged to select a first computing device and a second computing device from the computing devices. The first computer video interface is arranged to receive a first image from the first computing device, and the second computer video interface is arranged to receive a second image from the second computing device. The image processing unit is arranged to compose the first image and the second image to be a synthesized image. The console video interface is arranged to output one of the first image, the second image and the synthesized image to the set of user interface devices.