The HDMI ARC is the latest version of the HDMI cable. The cable is used for newer versions of HDTV (high-definition television), HTIB (home theater in a box), receiver, and sound bar. HDMI 1.4 introduces the feature known as ARC (abbreviation for Audio Return Channel) among other features, and it uses two pins from the connector – first is the hot plug detect pin and second is the previously unused pin.
As an audio link, the main purpose of the "ARC" feature of the HDMI ARC is to act as a replacement for the other cables between the TV and the A/V receiver or speaker system. Such direction is utilized when the television acts as the generator or the receiver of the video stream rather than the other equipment. This is applicable in cases like when a particular app is being run on a smart TV like Netflix (a provider of on-demand Internet streaming media available to viewers from North and South America, United Kingdom, the Caribbean, and other countries), but the audio reproduction is taken care of by another device.
Without the Audio Return Channel, the audio output from the TV needs to be routed by using another cable (typically the TOS-Link or coax) into the speaker system. In terms of the pins being used, the HEC (abbreviation for "HDMI Ethernet Channel") and the HDMI ARC have something in common. Furthermore, the HEC and ARC support combined via one port or cable is also known as the "HEAC", or the "HDMI Ethernet Audio Control".