Hello, I have ST121HD20V boxes to connect an HDMI / RJ45 / HDMI laptop to a video projector. When I connect the computer just after powering the transmitter box, the image is transmitted to the video projector. But if I disconnect the computer or if it goes to sleep, as soon as I plug the computer back in, I no longer have an image. I have to unplug and replug the power supply of the box for the image to come back. Do the boxes go to sleep? Can it be disabled?
Thank you in advance for your help
Hello @Adrien and thank you for your interest in our Community.
Have you tried to change the EDID setting on your Transmitter? Simply toggle the little small white switch and let us know if this resolves the issue.
Emmanuel B., StarTech.com Support.
Hello, Thank you for your response. Yes, I tried in RX and TX mode but the problem is the same. For your information, I also tested with another set of boxes and the problem is the same. The boxes seem to go into standby if a video is not passing through. To reactivate them, I have to electrically disconnect the transmitter box and reconnect it to restore the signal. Since the boxes are installed in a false ceiling, it’s not very convenient…
Hello @Adrien,
Here is another solution: you can force a signal to remain active by connecting a display (monitor or TV etc.) on the TX’s local output and switching the EDID to “TX”. If you do not want or have the space for a display at the local side, you can also use a small EDID dongle instead.
This will ensure that the signal remains active throughout the connection chain despite losing the source device. This should resolve the issue for hard disconnects or energy-safe devices.
Emmanuel B.
Thank you for your response. I would like to try what you are suggesting but I cannot leave a screen connected to the HDMI output of the transmitter. You mentioned another solution which is to use an EDID dongle instead. I don’t understand? Do I need to put a second receiver on the HDMI OUT output?
Hello @Adrien,
Not a second HDMI receiver, simply an EDID dongle, or also known as “HDMI Dummy Plug”. These cost very little and will emulate a monitor being plugged and ensure a constant signal.
Emmanuel B.
Thank you very much for this very good idea! I was not aware of the existence of this emulator. I ordered it and will test it as soon as I receive it. Once again, thank you for your support.
Hello,
I tested with an EDID Dongle but the problem is that the signal is prioritized on the EDID. So, when I connect the boxes without the EDID, I have a display on my video projector but as soon as I plug in the EDID, the display disappears; I think it is sent on the EDID. My computer enters on the HDMI IN, and the signal is sent normally on the RJ45 but if I plug in the EDID on HDMI OUT, it must go to the EDID and not to the RJ45. I tried TX and RX, but the problem is the same. Is it possible to prioritize the signal output? Through the mini usb connector?
Thank you for your help
Hello @Adrien,
The signal is always sent through both. If you lose the signal when connecting the Dongle, it may be because the EDID Dongle is set for a higher resolution than what the projector can support (like if you have a 4K Dongle but 1080p projector). All you have to do in this case, is reduce the resolution and/or refresh rate so that the output signal matches what the projector usually receives. This only needs to be done once, as your computer will remember to match that resolution for the Dongle.
One more thing: when changing resolution, please make sure to verify the Advanced display settings and look under the “Active signal mode”.
Windows has a tendency of lowering only the Desktop mode, but still sending a 4K signal unless you force it under Display adapter properties.
You want Desktop mode and Active signal mode to both be set to your wanted resolution and refresh rate.
I hope this helps. Have an excellent day!
Emmanuel B.
Hello,
Thank you very much for your valuable advice. I will try this and let you know.
Have a nice day.
Hello, following your advice, I lowered the frequency from 60Hz to 50Hz on the second screen and the problem is solved! I have the display with the HDMI dongle. Thanks again for all your good advice.
Glad to hear it all works great now. Have an excellent day!
Emmanuel B.
