High Speed HDMI Cable with Ethernet: The Forgotten Channel
The cable contains an extra data pair that was meant to share internet between devices. In practice it found a more useful job carrying audio backwards.
Quick Answer
| Feature | Status today | Practical effect |
|---|---|---|
| Ethernet channel for networking | Rarely implemented | You almost never use it as a network |
| The same pair for audio return | Widely used | Carries television audio back to a soundbar |
| High Speed class | Up to 8.2 Gbps | 1080p and limited 4K |
| Premium High Speed | 18 Gbps | 4K at 60 Hz with HDR |
| Ultra High Speed | 48 Gbps | 4K120, 8K60, variable refresh |
For a modern system, a certified Premium or Ultra High Speed cable is the sensible choice, because it includes the pair and has the bandwidth the video needs.
Identifying the Right Cable
Certification wording
Look for the certified class name rather than a version number printed on the packaging.
Bandwidth for your signal
Match the class to the display resolution and refresh, not to the label on the box.
Length
Higher bandwidth reduces usable passive length. Long runs need an active or optical cable.
Return path support
Check that an optical or active cable explicitly supports the audio return path, since not all do.
Where It Matters in Practice
- Soundbars and receivers using the television audio return path.
- Any installation where only one cable fits behind a wall mounted television.
- Systems where lip sync correction is desirable.
- Long runs where an optical cable must carry audio back as well as video forward.
Choosing and Installing
- Identify the highest resolution and refresh in the chain.
- Choose the certified class for that requirement.
- Keep the run within passive limits, or go active.
- Verify the audio return path is supported if you rely on it.
- Test the highest mode and the audio format after installation.
Real-World Applications
- Television to soundbar with one cable.
- Receiver handling audio from television apps.
- Wall mounted displays with concealed cabling.
- Simple home cinema installations.
Related Guides
For classes, read HDMI adapter coupler. For conversion, see AV adapter. For adapters generally, start with USB adapter kit.
FAQ
Does the Ethernet channel share my internet?
In principle, but almost nothing implements it. Treat the channel as an audio return path.
Do I need a special cable for audio return?
It must include the extra pair. Certified High Speed and above cables do.
Is an Ethernet cable the same as an HDMI with Ethernet cable?
No. They are unrelated. An Ethernet cable is a network cable.
Will a cheap cable work?
For 1080p often yes. For 4K with HDR, use a certified class.