SX20 & C20 External Audio With or Without Content Sharing

[Dave Bohn]

We have a number of C20's and SX20's which some have a PC connected to the DVI external input (with audio) for content sharing.  The Rubbermaid carts these are on have a dedicated speaker for the PC and one for the codec.  I recently noticed we had audio coming from both speakers before and during a video call and also if we did not share content to the codec while not in an active call (PC had audio such as Youtube playing while we tested).  I assume the codec would control the audio feed and if we did not have sharing selected either with no active call or during a call it would be mute, that was not the case.  I looked around the settings and did not see a means to turn off the external audio unless we selected content sharing.  Did I miss something?  I assume the default would be no audio from an external input unless the content sharing feature was selected from the remote or touch panel.

[Acevirgil de Ocampo]

Hi Dave,

The scenario that you are experiencing is normal. Anything you plug-in as audio source  on the codec's line input will always be routed to the line output of the codec going to your speaker. Even without hitting the presentation button, the audio is always there. The only part you can enable/disable is the video content during presentation but not the audio.

This is normal for all Cisco Telepresence video codecs.

The only thing you can control for the audio is the volume and audio line input gain settings.

regards,

Acevirgil

[Dave Bohn]

I guess my only option on some of these carts is to pull the audio input from the PC.  We are getting audio feedback from the stethoscope mic since they are picking up their own feed from the codec.

Thanks for the fast reply.

[Wayne DeNardi]

Another option may be to feed the PC's audio in to the codec on one of the Mic inputs.  This then wouldn't play locally, but would be able to be transmitted to a far end endpoint.  You may need to tweak the levels if you do so.

Wayne
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[Getinge Technical Support]

Hello,

I need exactly this solution.

How can I connect a PC output to the Mic input of a SX-20.

We figured out that only on the Mic input the echo cancelling is possible.

In the data sheet is also mentioned that the Mic input needs a 4pin minijack cable.

We tried an adapter cable from TRS to TRRS, but it didn´t work.

Any idea what could help?

Best regards

Torsten

[Wayne DeNardi]

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@Getinge Technical Support wrote:

How can I connect a PC output to the Mic input of a SX-20.

There are a couple of issues you need to overcome to do that.  Firstly, the PC will generally output an unbalanced Stereo signal, and the Mic input expects a balanced mono signal, so you need to consider how you will convert the stereo to mono before sending it to the codec.  Once you have sorted that out, the 3-pole to 4-pole wiring should be a relatively easy thing to accomplish.

Note the old rules in the earlier posts (from back in 2015) about the line input always being active have changed in recent times with newer software versions.   In the CE9 software there are options under Configuration > Audio > Input relating to the Line 1 VideoAssociation where you can Mute the audio on inactive video, or tie it to a certain video input source.  You may have more luck with this than trying to adapt the signal to a mic input.