What is HDMI? HDMI is a digital input. HDMI also carries the audio signal (as does DisplayPort). HDMI is a very popular input to use, some monitors have more than one HDMI port. Please always check the specification so that the monitor you purchase has a compatible signal port with your PC/Laptop. Converter cables can be used and purchased separately, in the event you cannot use a monitor singnal cable which has identical connectors on both ends.