ARC Issue using Room Kit Plus and non-Cisco HDMI cables or HDMI to Cat 6 adapters

[David Kos]

Hi Cisco,

I have a client that had another integrator try and install a Room Kit Plus where the room kit codec was located under their conference table with the camera/soundbar located above their 86" Samsung monitor.  They are having an issue with the ARC based audio making it back to their Camera/soundbar, they get no audio.  They are using 15ft HDMI cables that advertise ARC compatibility but don't seem to be passing the audio back to the Cisco soundbar.  They did a test with a 3 meter Cisco HDMI cable and the ARC signal passed without issue.  Do you know if there is a length limitation in regards to ARC over HDMI?  or how the Cisco 3 meter HDMI cable may differ from another off the shelf HDMI cable.  I know that Cisco has a 5 meter HDMI cable option will that cable be able to pass the ARC signal as effectively as the 3 Meter Cisco cable that they used for testing.  I look forward towards any information that can be provided in regardsa to my questions, thanks for your time.

[Jonathan Schulenberg]

The two Cisco cables you specify are not active cables so it’s simple copper passthrough (the eight and nine-meter directional cables are active). I have seen lots of non-Cisco HDMI cables used without issue; the go to I see used a lot are Liberty Cable. The FSR fiber ribbon cables are also a popular choice for longer runs.

[Wayne DeNardi · Accepted solution]

It's not about the length of the cable, its about the signal attenuation.  The length of the cable will affect this, but so will the quality of the cable that's being used.

You will need to also check out the Category of the HDMI cable you are using - and for longer lengths (and higher bandwith to support higher resolutions), make sure you're using a Category 2 or Category 3 cable.  These should be able to be recognised as being marked as HDMI 2.0 or HDMI 2.1 compliant (The older Category 1 / HDMI 1.3 cables won't be good enough).