Question: what is the difference between hdmi 1 and 3?
Answer: HDMI 1 and HDMI 3 can be used for connecting any device to your TV. HDMI 2 MHL (Mobile High-Definition Link) is used for connecting compatible tablets, smart phones or other devices to your TV. HDMI 4 ARC (Audio Return Channel) offers two way communication between devices over a single HDMI connection.