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DX80 HDMI Input causes flickering




I have a MAC plugged into my DX80 as a second screen but the picture keeps flickering or going off for a split millisecond then returning..


While the picture is on its clear and correct and running at 1080p but the flickering is every 10 seconds or so


I am sure i read this was a bug in a previous version but i am on 10-2-4-46 now and i still have the issue.


Any ideas



17 Replies 17

Cisco Employee
Cisco Employee

Hi Andy, There was a bug created for a issue similar to yours, however it was cancelled after we were not able reproduce it. 

You have likely already seen this on the DX80 datasheet, but here are some of the resolutions supported on the HDMI input. 

Supports formats up to maximum 1920 x 1080 @ 60 fps (HD1080p60), including:

  640 x 480 @ 60 fps
  1280 x 720 @ 60 fps
  1920 x 1080 @30 fps
  1920 x 1080 @60 fps

High-definition inputs use progressive video formats


Ensure that the HDMI output on your MAC is using progressive scan, since using interlaced with the DX80 could cause this issue.  Either that, or lower your resolution  and see if that works.


Darren McKinnon

Cisco TAC




yes it's running at 1080p 60..


i have tried other resolutions but it's still the same..


could it be an HDCP issue?



No, I can't see HDCP being the issue here. Have you had this same experience on older software versions on the DX80?  Can you get the syslog from the DX and attach it for review?



yes I have hence I tried the latest Fw..


happy to get syslogs. Does the DX store them local as have not done it on a DX yet or do I need to use an external syslog server and turn on debug?


ps I don't have this issue on an Mx200 alough I know this is a different hardware / software stack as its not android based. 



You can get the syslog by browsing to the IP address of the DX80.  On the left, under Device Log, click Console log.  Now select syslog.txt.  When it opens in a new window, right click and save as syslog.txt.

Darren McKinnon

Cisco TAC


We were able to replicate the issue quite similarly if not worse. Here are the details:

2015 Macbook Retina 12" (USB Type C Machine) - OSX 10.10.5

Test 1 - Macbook plugged into the DX80 via a USB Type-C Adapter to HDMI. - Lags system and flickers blue every few seconds. - Recognized as 1080p 60Hz

Test 2 - Macbook plugged into a Generic 1080p HDMI monitor via the same USB Type-C Adapter to HDMI. - No lag, No blue flickering - Recognized as 1080p 60Hz

Test 3 - Macbook plugged into the DX80 via a USB Type-C Docking Station with HDMI (OWC Dock)  -  Same lag of system and flickers blue every few seconds. Recognized as 1080p 60Hz

Test 4  - Macbook plugged into a USB-C > Apple VGA Adapter > VGA Cable to a Crestron HDMI Scaler (HD-SCALER-VGA-E) > HDMI out to the DX80 - No lag, No flicker.

All of that said, I believe we have distilled it down to there being an issue with data coming out of the DX80 causing the issue. As the moment we strip away the extra information that HDMI carries and switch to analog, the monitor works fine. A unit as high-end as this shouldn't need a $1000+ scaler sitting between it and it's signal to produce a passable image with a newer Macbook.

If you have any further suggestions I am all ears.

Michael M | Broadcom Limited 

Hi All,

Understand that this is an old thread. I just upgraded my Mac for a 2016 Pro . I use a DX80 as an extended screen. I am seing exactly the issue that is described here. Was there ever a resolution found ?

What software version are you running on the DX80?

Are you running the old Android software which had an end of support announcement in April 2017, or are you running the new CE9.x software?

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

I also realize this is an old thread but I started having this same problem with the constant flicking every 3-5 seconds on my DX80 connected to my new Macbook over the past month.  DX80 is running the latest firmware version "Spark Room OS 2018-02-21 7a86dbf1037".  


Any help would be greatly appreciated.



Since your a Cisco employee, you should be able to open an internal ticket to have someone help you. It also appears that your DX80 is registered to Spark, since you're running the Spark Room OS software, in which case there isn't much, if anything a typical user can do since the web interface of the endpoint is locked down.


I'm also having the same issue.  I'm using a Macbook Retina with the USB-C to HDMI adapter and my screen flickers every 10-15 seconds.  I can confirm this is only on the DX80 (I test three of them) and is not the cable or adapter as that combination produces flicker-free image son other 1080p displays.  

Exact same with me.  I upgraded to and it's even worse.  My DX80 screen freezes.  If I stop displaying and then start again it refreshes only to freeze again in less than 5 minutes.  Back rev'd to and now only have the flickering issue.

Cisco Employee
Cisco Employee

I have the exact same problem now :( any idea what to do about this?



Can you check the bug described on the following link:



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