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New Member

C20 and SX20 no longer support HDMI digital audio from a laptop


If anybody has run into this problem or has a solution for it I would be very appreciative.


I recently encountered problems with an SX20 and a C20 where the digital audio from our PC, connected to input 2 (the DVI connector with a passive HDMI adapter) "was" passing digital audio from the PC to the codec and from there to our display monitors but both units stopped about a month ago.

No changes have been made to the codecs, no firmware updates have been performed and there is no reason for anything to change.

The Windows PCs and laptops that we use are standard but now Windows no longer detects an "audio display device" on the SX20 and C20 DVI inputs, this was not the case when the equipment was installed.

In troubleshooting I also plugged the laptop into input 1 the HDMI camera input and Windows detected an audio display device right away

"C20" or "SX20" are clearly available in the windows mixer.

I also have noticed that I no longer have an on screen menu option for changing the connector on input 2 from "DVI" which does not support digital audio to "HDMI" which does support digital audio.

I have scoured the API guide and found nothing that will correct this problem.

If anybody has a resolution to this problem please share it with me.


Thank you




Hi Dan, Currently I have same

Hi Dan,


Currently I have same issue with you,

have you solve this issue?





VIP Green

If you're expecting to feed

If you're expecting to feed Audio in via the DVI connector, that will never work.  DVI is for Video only.  You'll need to connect the audio in separately.

If your issue is about being able to see the different sources, then you may need to check the "Visibility" of the source - it may be set to "Never", or, more likely, "IfSignal" which means it'll only be shown if the endpoint detects a valid input signal - it won't be shown if there is nothing connected.

The other issue, trying to feed audio in over HDMI may be bug CSCuh72577.

Please remember to rate responses and to mark your question as answered if appropriate.

Please remember to rate responses and to mark your question as answered if appropriate.
New Member

Wayne,  you are absolutely

Wayne,  you are absolutely incorrect.  We have it functioning just fine on an SX20 with an HDMI to DVI-I converter.  

New Member

I cant find a Audio pin in

I cant find a Audio pin in the dvi connector...

You can use the Audio Input (3) to transmit some aux(iliar) audio




Network (RJ45)


Loudspeaker (3.5 mm mini-jack)


PC video input (DVI-I input)


PC audio input (3.5 mm mini-jack)


Second monitor (HDMI 2 output)


Microphone 1 (3.5 mm mini-jack)


Main monitor (HDMI 1 output)


Microphone 2 (3.5 mm mini-jack)


Camera input (custom)


2 USB (for future use)


Kensington lock

Thats an example of a cisco sx20 connecting cable, take a look of the DVI-I Connection.

Wayne is 100% correct, the

Wayne is 100% correct, the DVI standard NEVER included audio; just look it up.  You either have a magical SX20 or you are missing an audio cable being connected...

Thank you,
Justin Ferello
Technical Support Specialist, ScanSource KBZ



None of this is possible, the DVI standard has NEVER included audio.  Also, the SX20 & C20 only have a DVI input for the second source, you could NEVER switch from HDMI to DVI for the source 2 input.

Both codecs have an HDMI input for source 1 and a DVI input for source two.

The only way this could possibly work is you would have a DVI cable off the HDMI converter to the codec and then a 3.5mm stereo cable off the HDMI converter to the codec.


Thank you,
Justin Ferello
Technical Support Specialist, ScanSource KBZ
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