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Island Health

Presentation Source Not Detected on SX20

My organization is currently deploying a large number of SX20's to replace our aging Video Conferencing equipment, and I've run into an issue with the SX20's not detecting the presentation source.

Our standard configuration for the SX20 presentation cables is a DVI-to-HDMI adapter in the codec, with an HDMI cable running to the meeting room table. At the meeting room table we are attaching a ring of adapters for presenters to use, including an apple adapter, and various sizes of Display Port and HDMI adapters. The HDMI-to-Display Port Mini adapter is the most commonly used within our organization. In a couple of instances (but not all) when presenters have connected their laptops to the HDMI cable using the Display Port Mini adapter the codec does not detect a presentation source. This issue appears to be intermittent - one codec was not displaying content, but is now responding, and hasn't failed in a couple of weeks.

I recently deployed another endpoint where the presentation source wasn't being detected, tried multiple laptops, nothing. I replaced the HDMI cable and adapters with a DVI-VGA cable and it now works fine. My question is - do these adapters interfere with sending content to the codecs? Is the configuration we are attempting to deploy going to continue to run into these issues?



Are the laptops using a supported resolution?  Refer to Table 2 of the SX20 Data Sheet.

What happens if you connect directly to the codec, removing any adapters or converters that is being used?

Are the laptops sending HDCP content?  If so, the codec cannot accept HDCP content and will show a blank screen.

Is the video signal progressive or interlaced?  The codec and only accept progressive video.

Thanks for your response,

The laptop is using a supported resolution, and is not sending HDCP content. The signal is also progressive, and not interlaced.

When swapping the presentation cable from the HDMI cable with adapters to a DVI-VGA cable there are not issues presenting content. However, we are trying to move away from VGA as it is an old, analog, technology, and we are seeing and increasing number of guest presenters bringing laptops that don't have VGA ports.

Additionally, we currently have two codecs deployed that are running with the above described configuration that aren't having issues displaying content.

Macs like to require HDCP even though you are not "sending HDCP content".

Also, VGA>>DVI uses entirely different pin outs than the HDMI>>DVI adapter. If your laptop is working in other rooms, then you need to verify the cabling in the problem room and also check the codec config.

Go to System Config>>Video>>Input DVI2, verify "type" is on auto or DVI.

Also, go to Peripherals and tell us if anything is showing on the Input 2/DVI for resolution. If its just a dash then the codec is not seeing signal at all. Input 1/HDMI should be showing 1920x1080/60

Aaron Wilson

Patrick hit some of the main answers. I have adapted a lot of DP/HDMI/DVI over the years and taken many classes on it, here are some additional insights:

-When dealing with blank screens for the PC into 1080p and 720p mode.

-Make sure you are not using incorrectly installed Redmere (directional) cables

-Macs are notorious for requiring HDCP even when no application has triggered it. I have most my experience with Lenovo/Thinkpads and have not ran into this issue with them. Force disable HDCP to see if the image comes back

-Verify what the codec shows as an input res. If HDCP is doing screen blanking you should see registered resolution on the codec. Screen blanking is literally a black image over a valid video signal, so resolution still passes.

-In order for a PC to support a mDP/DP to HDMI/DVI (these two are the same type of TMDS signal) adapter, it needs to be dual-mode DP connector, usually marked with DP++

-Make sure your HDMI run is not too long. You should be able to do 30-50ft passively with a proper HDMI cable. Over 50ft you want Redmere. Over 75ft I would go HDBaseT.

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