HDMI Headaches

[Aprice]

Hi All,

 

Having just moved into a new building we are now having the dreaded issues with HDMI and Promethean boards.

 

The setup is as follows:

 

Promethean Board

5M HDMI Cable

Faceplate

HDMI cable to PC (Acer Veritron)

 

Sometimes when PCs go to sleep the board just won't detect. Restarting the machine generally gets it going again.

 

I've had these sorts of issues in the past with previous BSF builds, and never quite understood exactly what the issue was. usually a HDMI cable ended up being put in just going from the PC to the back of the board, messy but worked. Also same sort of problems with USB cables to the older projector based Prometheans, even active USBs never got it working perfectly.

 

We had a meeting with the AV company today who were all to aware of these sorts of issues. Lots of ideas and theories thrown around but no certainty. Currently Aura cables are fitted, they've put a Vision one in to test, so far so good but these I've seen these sorts of issues with as well in the past with.

 

The usual bits have been checked, BIOS updates, board FW e.t.c

 

My theory is it could be the number of connections in the cable, and that HDMI was designed for running 10M through trunking and faceplates.

 

Wondering who else has had these sorts of problems before? Did anything ever fix it or did users just give up reporting it?

 

Cheers Alex

[networkmangler]

We had an issue getting our new Smart Interactive panels to work

 

To solve the issue we had to make sure that the display settings were set to a refresh rate of 60Hz.

 

We also had the issue of the board sometimes not working after the PC had gone to sleep. We showed the teachers that if you press the windows key + P, it opens the display settings and if they selected duplicate it started working again

 

We haven't had any issues reported with them since

[Zourous]

I’ve had numerous issues down the years. Here are a few pointers:

 

Yes, more connections do not help so try to limit them, but then if you go a to b in one length and the laptop \ PC end gets broke…

 

Look to see if there is a maximum supported distance from the screen or projector. We had Smart E70 screens that caused me issues for years. When I looked in the manual the max distance was 3m which isn’t far at all.

 

You can get booster adapters, (yes another connection) but these helped in our situation above.

 

If you get a temperamental connection, where sometimes it’s ok but other days not, you are probably pushing the distance or number of connections.

 

General HDMI’s are not meant to go much further than 10m.

 

You can buy some HDMI over ethernet adapters that can go much longer distances but I haven’t much experience of these.

 

Expensive cables don’t mean better quality as such. I opened another thread on here some time ago debating this fact and that was the general opinion.

[slugshead]

Expensive cables don’t mean better quality as such.

 

Linus did a really interesting video on testing HDMI cables

 

[FN-GM]

We had problems like this. In short, this can happen due to low quality cables.

 

Interesting if using a DisplayPort (this side connected to the PC) to HDMI cable all the issues went away. No need to replace the cables in the wall.

 

I also had success with directional cables.

 

You can buy some HDMI over ethernet adapters that can go much longer distances but I haven’t much experience of these.

 

These work well if they are powered and using the Ethernet for IP traffic - via a switch. But they are expensive.

[caffrey]

Never really liked those HDMI over Ethernet, the last AV job I did we used Fiber Optic HDMI cables for long runs and they worked really well. The price was similar to a HDMI over ethernet adapter too

 

https://www.kenable.co.uk/en/search?controller=search&poscats=0&s=hdmi+fiber

[Aprice]

We do have a couple of the Fibre optic ones which so far have worked well, apart from one which may be intermittent. Possibly down to the faceplate it's plugged into though. I'm thinking they might be the way forward.

[Aprice]

 

 

My theory is it could be the number of connections in the cable, and that HDMI was designed for running 10M through trunking and faceplates.

 

 

*Correction*

 

Wasn't designed for running 10M through trunking and faceplates.

[Aprice]

We had problems like this. In short, this can happen due to low quality cables.

 

Interesting if using a DisplayPort (this side connected to the PC) to HDMI cable all the issues went away. No need to replace the cables in the wall.

 

I also had success with directional cables.

 

 

 

These work well if they are powered and using the Ethernet for IP traffic - via a switch. But they are expensive.

 

 

They did try this, swapped them all out for display port to HDMI, still doesn't seem to have solved it. We were all hopeful that would be the magic bullet.

 

Starting to think VGA might be the way forward!

[chazzy2501]

We've been having trouble with 4K interactive panels. I bought some EDID injectors that fool the laptop into only sending 1080p/60 making the connection more reliable.

 

https://www.amazon.co.uk/Hakeeta-Emulator-Displays-Support-Compatibility-default/dp/B07W6Q3CVN/ref=sr_1_10?crid=1X385GUKFCOM8&keywords=edid&qid=1641890000&s=electronics&sprefix=edid%2Celectronics%2C73&sr=1-10

 

also optical HDMI leads are a thing and should negate distance and interference issues. Some amazon basics are optical! (look for source and destination labels)

[synaesthesia]

Very aware of this - definitely use optical cables where you can. Apparently every join in a HDMI connection is the equivalent of 2 or 3 meters of cable in loss, and you have 2 of those in a faceplate setup (turning a 5m cable into 10-11m worth of loss), and some devices are more sensitive to this than others. For example, the Intel Iris chipset is bloody awful in that regard.

[Tom_P]

I had similar issues when we upgraded our boards.. Using HDMI to display port as @FN-GM suggested resolved ours.

 

By luck i grabbed a hdmi to displayport by mistake.. When i got to the board and reliased i had the wrong cable thought i would give it a go anyway (partly down to laziness on going back and forth to the office ).. sorted the problem. Ordered up these cables for the rest of the screens and havn't had these issues since.

 

Moral or the story.. Laziness isn't always a bad thing.

[synaesthesia]

Indeed - there's better shielding in Displayport which negates some of that, but again another meter or so and the problem re-appears (We have mostly DP to HDMI around the site)

[jmak]

The optical cables that caffrey mentioned look like a good option. I didn't find anything affordable when I was looking so I went with these Cat5 extenders (note that they use an "Ethernet cable" but it doesn't go anywhere near your network).

https://www.amazon.co.uk/dp/B08316HNQ6/ref=cm_sw_r_awdo_navT_g_dl_TEVYREBAG2YA21HH3TX9

 

Connection has been rock solid, but I did find that when they were left on for several days some funky artefacts appeared. Reboot fixed that.

[caffrey]

The other issues with those extenders is that they require power and if you haven't got spare you could run into issues

 

This is the one I used, it's handy as it's got a detachable plug for easier cable pulling

 

https://www.kenable.co.uk/en/hdmi-cables/hdmi-20-cables/hdmi-20-aoc-cables/10771-detachable-plug-hdmi-20-active-optical-cable-aoc-for-wall-installation-4k-50m-010771-5054338107714.html

Edited January 11, 2022 by caffrey

[Chris_Cook]

I'd also recommend the AOC fibre cables as well. CPC do some for not a lot. I was very impressed with how they just worked even on a 30m run.

[Aprice]

Thanks all, It seems optical is the way forward.

 

I think it’s definitely something the DFE should look at adding to a specification, having worked now in multiple new builds with the same issue everywhere.

 

While I don’t like the issues the faceplates bring, I do think they are somewhat required, especially if it’s protecting the more expensive optical cables in the trunking. Although a quick call with Promethean today, indicated that are aware of significant issues with faceplates and just recommended one cable from the board to the PC (ideally 3M or shorter), which is understandable.

 

The active adapters I like, however I suspect getting the added sockets required into the building spec may be a challenge, especially if it can be countered with just optical cables.

 

Thanks,

 

Alex

Edited January 11, 2022 by Aprice

[SamanthaD]

My recommendation has always been bin the faceplates. I work on each connection adding an extra meter to the chain, so a faceplate adds 2m plus the pigtail cable. Starts getting flaky over distance. I understand the concern over leaving expensive cables to be plugged in by users, but anything over 5m really has to be an active cable (the directional ones, though I'm being told nowadays the power output on HDMI on newer machines isn't really enough to power the amplifier) or fibre. CatX is great if you're running other data with it such as RS232 or multi channel audio (we use RS232 for projector / screen control) but otherwise is a bit expensive and clunky compared to fibre HDMI.

 

I recommend a USB-C dock (with a short, sacrificial USB-C extension) that then gives the user network, power, display and any in-room USB devices (touchscreen, cameras and microphones perhaps?). Plug the fibre HDMI into that which then goes directly to the display, no breaks in the chain. You provide the user with a 1 cable solution that gets around them having to carry video adapters, PSU's etc (also stops them unplugging power sockets to power their laptops!)

[chazzy2501]

as @SamDavis says, I have the single cable go from the output to the docking station. The dock is USBC and does power, picture(sound), Interactive, Network.

 

The cable can come out of a wallbox fitted with a brush plate for neatness.

 

and of course I have all staff with a USBC displayport alt mode laptop now. (the TAs got some of those DFE dynabooks

[ITGuyNW]

More expensive than a HDMI cable but I've used a Microsoft wireless adapter before now instead of HDMI without hassle on a Promethean Titanium.

 

Microsoft Wireless Display V2 Adapter - Black | Ebuyer.com