HDMI leads - reasonably priced supplier of 15m HDMI 2.*?

I was referring to 'no maximum length for an HDMI cable is specified'

And plenty don't use full bandwidth anyway.

CCTV is unlikely to be 8K@120fps so doesn't need full bandwidth ...

That adapter is so wrong on many levels for reliable HDMI transfer.

But then ignoring the rest of the sentence which qualifies that statement.

Length you can use hdmi,and other typesignals does seem to be dependent on the suck it and see principal, IE although you can join the max length leads together the ability for them to work reliably can vary a lot. I don't know how they are terminated at the two ends in the equipment, but, its my guess its as cheap as they can get away with. Occasionally, with less than cable between a computer and Samsung tv, it won't switch, and yet pulling out the plugs of the hdmi and putting them back usually cures it again. Contact resistance maybe? Also a ticking nois is often heard on nearby radios when there is no signal when the cable is plugged in, once again wiggling the cable can sort that too, which suggests the screening connection is not as good as it could be. Brian

Maybe - but just....

Nope, not when you arent using the maximum bandwidth.

A lot of HDMI equipment won't power up the output drivers unless it sees something on the other end of the cable.

Laptops used to do that a lot with VGA ports, and I once encountered a monitor which did the same with its receiving circuits. I was unable to get the two to communicate. No combination of plugging in and powering up would work.

They're not great connectors, being basically what used to be PCB edge connectors. When PCBs started carrying high frequencies, they switched to proper connectors. There's no way that a connector of the HDMI type can terminate the cable really accurately, which is fairly important at the frequencies involved and the low signal levels that crawl out of a long cable. SDI works over about 100m reliably, and maybe up to 150m, but it does so on coaxial cables *and* connectors. And that's a single-ended signal, not balanced as HDMI is.

Following up with a global thanks to all for comments and suggestions. The intention is/was to be able to view the CCTV from the comfort of an armchair to be able to review and fast forward older footage that may not have triggered an alert. The number of occasions that this will happen are very limited so, on balance, I think I may simply stick with what I have already in the loft. Basically I was being lazy! and the costs look to be outweighing my laziness. Thanks again everyone, I do appreciate your time.

I don't for a moment dispute that. However, I do wonder whether it might still work OK for reasonable cable lengths. The reason I investigated such connectors was that a relative had an HDMI cable with a broken connector where the cable itself was plastered into a wall. The cable was only a few metres long. I haven't actually tried it yet as a different workaround was found. As for the "wrongness" of the connector:

So long as only one screw terminal adapter is used, with a properly constructed connector at the other end, the inevitable reflections from the mismatch will be absorbed by the source and destination termination resistances so multiple reflections are unlikely to be a big problem. Similarly, for long cable lengths the cables losses will absorb much of the reflected power so the main effect will probably be increased high frequency attenuation. This may or may not matter depending on the video resolution etc.

It does feel as if there are many situations where such a connector could usefully salvage an otherwise difficult situation and there is little to lose by trying. Does anyone have any actual experience with these?

John

Yes, I suppose I should be surprised that a breakout box like that even exists...

In the modern world, one would expect CCTV output to be stored on a HDD/SSD which can be served over a LAN, wireless or wired. Like a NAS.

You can go against the grain, but sometimes it is just better to bite the bullet and do it the standard way.

Are you sure this DVR doesn't already serve the discs on over Ethernet. In which case, you just need a cheap computer connected to the TV, even a Raspberry Pi, would do it.

There doesn't seem to be any compensation for path difference on the four pairs. At lower rates.

Whereas on PCI Express, the de-skew allows a seven inch path length difference between diff pairs. When you look at the totality of the feature set of PCIe, it's nothing short of amazing. The stuff it tolerates. You can even flip the bus, and connect 0..15 to 15..0 at the other end. PCIe uses diff pairs too.

Paul

Because it’s coming from Rod Speed. Do keep up. ;-)

Tim

I thought the practice in the past, was not to certify HDMI cables for anything. You just got a cable, and had to use customer comments as to how good the cable was.

Are the cables now "certified", have eye opening verified or BERT tested or the like, so we know they will work at the full rate ?

For things like SATA cables (6Gbit/sec transmission), the wire in all the cables is of the same construction.

HDMI allows manufacturers to screw around. They cannot modify the dielectric too much, or the characteristic impedance might be wrong. I understood, at one time in the distant past, there were some HDMI cables with lower loss than commodity cables. And were priced as such. But there were no specs attached, so you could know exactly what you were buying.

Paul

Does the box have a "remote-in" capability ?

Like an Ethernet cable on the back, that can be connected to your router ? Or Wifi even.

There might be other ways of doing this, that are in the realm of the "do-able".

Paul

There's an HDMI certification programme:

Theo

Currently there is a monitor and mouse in the loft to enable 'boundary lines' to be set and also to fast forward/'rewind'. An ethernet connection is made to router and I can then view notifications on my mobile. The notifications show a period before and after an 'event' and can be saved to my phone if necessary.

This all works well but the facility to set up or alter 'boundary lines' or to speed through older footage can only be done via a mouse connection to the box and via a larger screen than most mobile phones have (to be able to pick the specific areas to be protected and give alerts).

What I was seeking to do was to use the TV screen in the living room plus mouse to review older footage and set the 'boundaries.

The occasions that will require this are few and far between so its not worth me trying to set up something more complicated (for me, but probably not others) than running a couple of cables through existing ducts.

?? The signals aren't terminated by the connector, but by load resistors on the PCB or the receiving IC.

Singled ended signals do fine if using an appropriate cable type.