HDMI ARC Output as Audio Input?

Question:
My Sony DAV-DZ640K home theater in a box (HTIB) includes a receiver with HDMI Audio Return Channel on its HDMI output. Can this serve as an HDMI audio input? After all, HDMI ARC basically transfers audio from TV to the receiver.
– Srijan Saha

Answer:
Sadly, no. ARC is designed to convey audio from the HDMI input of an ARC-capable TV back to the HDMI output on an ARC-capable receiver, traveling in the reverse direction compared with the normal signal flow from the receiver’s output to the TV’s input. ARC uses different pins within the HDMI connection than those used to carry audio from an output to an input—specifically, the only unlabeled pin in the diagram above and the one labeled “Hot Plug Detect”—and no conventional HDMI output sends audio using the ARC pins.

For those who aren’t familiar with HDMI Audio Return Channel, it sends the audio from a TV’s internal tuner or online streaming apps to an A/V receiver along the same cable that otherwise carries the receiver’s audio and video signals to the TV, as shown on the right of the diagram above. Without ARC, you’d have to connect a separate cable from the TV’s audio output to the receiver’s audio input, as shown on the left, to hear the sound from the TV’s internal tuner or online apps.