Skip to main content

Digital Trends may earn a commission when you buy through links on our site. Why trust us?

Addition of Cable Power to HDMI simplifies longer cable runs

According to the newly release HDMI 2.1a Amendment 1 specification, longer HDMI cable runs will soon be possible, even without the help of an additional power source. Amendment 1 introduces “Cable Power,” a feature that lets an HDMI source device, like an A/V receiver, game console, or streaming media device, provide the additional power needed to keep a signal strong enough to survive a journey that extends further than a few meters.

If you’re raising an eyebrow right now because you’re already using a really long HDMI cable with no problems, it might be because you’re only sending lower-bandwidth content, like 4K video at 30Hz, possibly with HDR10. That kind of content only needs a Premium High Speed-rated HDMI cable, and these cables can indeed run to lengths of up to 25 feet without the need of an active cable (a cable that gets a signal boost from an external power source).

Related Videos
The Vizio M-Series 2.1 soundbar has two HDMI ports.
Simon Cohen / Digital Trends

However, any content that requires the full 48Gbps of an Ultra High Speed-rated cable (think uncompressed 8K@60Hz, 4K@120Hz, Dolby Vision, along with Dolby Atmos in TrueHD) will struggle to make that same trip. Cable Power has been introduced as a way to make these longer runs possible, by injecting the extra power needed from a device’s HDMI output itself, no external power sources needed.

For the new feature to work, both the source device and the HDMI cable will need to be compatible with Cable Power. Hopefully, both devices and cables will be clearly labeled so you know if they support Cable Power, but no official logo or wordmark has been created to help us quickly identify the presence of the new tech.

When using a Cable Power-capable device and cable, only one end of the cable can be plugged into the source device — this is the end that is used to receive the extra power. If you get it backward, no harm will come to your gear, but the cable will not deliver any signal at all. For those who are contemplating cable runs inside walls or other confined spaces, getting the cable ends oriented correctly will be very important.

The Monoprice RedMere HDMI cable.
A Monoprice HDMI cable with RedMere technology.

If you buy a new device that is Cable Power-enabled, you don’t have to use a Cable Power-enabled cable — the new ports are backward-compatible and your existing HDMI cables will still do what they have always done.

And, by the same token, if you decide to buy Cable Power-enabled cables — perhaps as a way of future-proofing an installation, but you don’t own any Cable Power-enabled devices yet — that’s OK too: Cable Power-enabled cables come with separate power connectors so that you can power them with a 5-volt USB adapter (typically Micro-USB or USB Type-C). You must power these cables in order for them to work, but when you eventually upgrade your source device to one that is Cable Power-enabled, you’ll be able to ditch the USB power adapter, giving you a cleaner installation.

If this sounds suspiciously like RedMere technology — which some HDMI cables use to harvest a little extra power from the source device to allow longer runs — that’s because it’s a very similar idea. The difference is that RedMere cables aren’t able to harvest enough power to allow the full bandwidth of an Ultra High Speed cable to be extended.

Curiously, even though Cable Power is an amendment to HDMI 2.1a (which itself is an update of HDMI 2.1), you’ll be able to buy a variety of speed-rated cables that support the feature. In other words, if you don’t need to send very high bandwidth content over your HDMI cable, but you still want the ability to do a really long cable run without plugging the source end of your cable into external power, you’ll be able to buy Standard, High Speed, and Premium High Speed, (in addition to Ultra High Speed) cables that support the feature.

Cable Power-enabled cables will still work with HDMI ARC/eARC, as long as they have one of the following labels:

  • Ultra High Speed HDMI Cable
  • Premium High Speed HDMI Cable with Ethernet
  • High Speed HDMI Cable with Ethernet
  • Standard HDMI Cable with Ethernet

Like the idea of Cable Power but hoping to avoid a new product purchase? Unfortunately, it looks like new hardware will be needed on the device side of the equation. A spokesperson for the HDMI Licensing Administrator tells Digital Trends that Cable Power requires chips in the source devices that will need to be manufactured specifically for that feature.

Editors' Recommendations

T-Mobile customers can now get MLS Season Pass for free
MLS Season Pass on T-Mobile Tuesday app.

As was foretold, T-Mobile customers can now grab their free subscription to MLS Season Pass on Apple TV. It's part of the "T-Mobile Tuesdays" incentive that gives subscribers free stuff throughout the year, and the latest in a string of streaming-related freebies made available by the wireless provider.

All you'll need to make good on the promotion is a T-Mobile account and the T-Mobile Tuesday app. From there, you'll be prompted to redeem a unique code. Log in to your Apple account, use that unique code, and you're good t ogo.

Read more
Samsung’s 2023 Neo QLED TVs start at $1,200 — and you can buy them this week
Samsung's 2023 Neo QLED 4K and 8K TVs.

We got our first taste of Samsung's 2023 mini-LED backlit, Neo QLED TVs at CES 2023, and now we know what (most of) the new models will cost. The company has released pricing for its flagship QN900C Neo QLED 8K TV, as well as its 8K QN800C, and three 4K models: the QN95C, QN90C, and QN85C. All five TVs will be available in a variety of sizes at a mix of authorized retailers starting the week of February 20, 2023. Not every size will be available immediately and the king-of-the-hill 85-inch QN900C remains under wraps for now.

Though there are specific differences among the new 2023 Neo QLED models, all five possess:

Read more
Can we talk about wireless audio’s missing speedometer?

Imagine someone spending $150,000 on a Porsche that had no speedometer. “This fine sports car can do zero to 60 in under three seconds.” Uh, how do I know? “Doesn’t it feel fast when you drive it? Trust us, it’s under three seconds.” Probably wouldn’t fly, would it? 

And yet, this unlikely scenario is exactly what’s happening in the world of wireless audio. 

Read more