Skip to main content
  1. Home
  2. Audio / Video
  3. News

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

By

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).

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.

Recommended Videos

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.

Related

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. Image used with permission by copyright holder

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

Topics
Simon Cohen
Simon Cohen
Contributing Editor, A/V
Simon Cohen is a contributing editor to Digital Trends' Audio/Video section, where he obsesses over the latest wireless…
Epson Home Cinema LS11000: $3999 for 4K, HDR projection
Side view of Front view of Epson Home Cinema LS11000 4K HDR laser projector.

After debuting its $4,999 flagship Pro Cinema LS12000 4K HDR laser projector earlier this year, Epson is back with a slightly more affordable way to project 4K HDR images at home with the $3,999 Home Cinema LS11000 4K Pro-UHD laser projector (V11HA48020). It's available starting in late March through the Epson online store and select retailers.

Other than the colors (black for the more expensive model versus white for the Home Cinema) and some performance differences, the LS11000 and LS12000 share a lot of the same features. Both use Epson's multi-array laser diodes as their light source, which is converted into a viewable image through a triple-chip LCD system. The company claims this gives the projectors incredible picture brightness, black contrast, and color accuracy, with 100% of the RGB color signal for every frame. It also avoids problems like rainbowing or uneven color brightness that can affect some other projection technologies.

Read more
HDMI 2.1a is on its way. Here’s what you need to know
HDMI Cable

Most of the A/V industry -- and most of the folks who buy A/V products -- are still coming to grips with how the various features of HDMI 2.1 affect TVs, soundbars, and a whole slew of other devices. But you can’t halt progress, and the next version of the HDMI standard -- known as HDMI 2.1a -- has already started its slow roll toward certification and eventual adoption. What does this new specification include, how will it affect you, and what will you need if you want to take advantage of it? We’ve got everything you need to know.
A small upgrade for a small group of people
The first thing you should know about HDMI 2.1a is that you probably don’t need it. As a minor update to the HDMI 2.1 specification, it only introduces one new feature: Source-Based Tone Mapping (SBTM).

We’ll get into what SBTM is and how it works in a moment, but here’s the TL;DR: Unless you are a gamer looking for the ultimate in HDR performance, or a PC user who routinely works with a combination of SDR and HDR content, you can safely ignore HDMI 2.1a for a long time to come. You don’t need to buy new equipment and you don’t need to worry about compatibility with the new version.
What is Source-Based Tone Mapping (SBTM)?

Read more
What is HDMI 2.0b? Here’s everything you need to know
Three HDMI cables held in someone's hand.

Wiring up your TV is a fairly cut and dry process, and thanks to advancements in A/V technology, there's pretty much only one cable you'll need for any new home theater component, and that's HDMI.

The all-in-one digital connection has created a cornucopia of ways to make hardware ready for the expanding A/V world around us, allowing for innovations like 4K Ultra HD and 8K resolution.

Read more