This document was generated from CDN thread
Created by: Kevin Huysegoms on 06-04-2011 05:08:32 PM
Hi,
A Tandberg C60 system has 2 HDMI inputs coming from a Crestron DigitalMedia switcher. The output of the Tandberg goes directly to a display. Turning off the C60 with the ON/OFF button on the back side, will cause the HDMI output on the switcher to fail. This part of the switcher needs a reboot before it regains its functionality.
This issue doesn't occur every time the C60 is powered off but it happens 3 out of 4 times depending on the firmware in the C60.
Trying to reproduce the issue with 2 C60's running different firmwares, gave us different test results:
- 4.1.0.247017: easy to reproduce
- 4.0.1.240265: hard to reproduce
After some debugging, we could conclude that pin 13 of the HDMI cable (CEC) was the culprit. Cutting the wire from the HDMI connector on the input of the C60 solved the issue.
I was wondering if someone could elaborate on the data being sent on the CEC channel and what happens on the channel when the unit is turned off.
Thank you in advance.
Regards,
Kevin
Subject: RE: Turning off C60 will cause input source to fail
Replied by: Roger Boe on 07-04-2011 09:08:47 AM
Hi Kevin,
This is strange as we currently does not use CEC in any of our products and hence we are not controlling this channel.
Best regards
Roger
Subject: RE: Turning off C60 will cause input source to fail
Replied by: Kevin Huysegoms on 11-04-2011 12:18:38 PM
Thank you for the answer Roger - I have some extra questions though.
If you're not using CEC in any of your products, could be that the CEC lines are used for something else?
How are you controlling a Tandberg camera connected to the HDMI input of the C60? Would that perhaps be over the CEC lines?
In case the CEC lines are not used at all, is the CEC pin connected internally to a pull-up resistor or is it grounded?
Thank you.
Regards,
Kevin
Subject: RE: Turning off C60 will cause input source to fail
Replied by: Roger Boe on 14-04-2011 10:50:20 AM
Hi Kevin,
The CEC is not used for something else. The plan is to start using CEC but it is not supported yet on any released software version. The Camera is controlled using RS-232 over a separate cable going to the camera.
The CEC line is pulled up to 5V internally, so when you turn off the equipment the pull up can become a pull down. So what you see here is possible as you can get power over the HDMI line from the other device that is not turned off.
Best regards
Roger
