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Old December 2nd 18, 02:57 PM posted to alt.comp.hardware.pc-homebuilt
Paul[_28_]
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Default "HDMI with ethernet" feedback into DVI blowing up monitor ?

wrote:
I am newb to HDMI, apperently there are 4 types, the cable I used was described on the product box as:

"High Speed HDMI Cable with ethernet"

I am now worried that this might have caused damage somehow ? Hmmm...

4 types described here, with a 5th on the way:

https://www.pcworld.com/article/2030...s-supreme.html

"
Standard HDMI Cable: Provides sufficient bandwidth for only 720p and 1080i resolution video.

Standard HDMI Cable with ethernet: Has the same bandwidth, but adds support for 100Mbps ethernet.

High Speed HDMI Cable: Provides more bandwidth, and can carry video with a resolution of 1080p or higher (up to 4096x2160, or 4K, but at a maximum refresh rate of just 24Hz, which is fine for movies, but terrible for games). This type of cable can also handle 3D video.

High Speed HDMI Cable with ethernet: Supports the same resolutions as High Speed HDMI Cable, as well as 3D, and adds support for 100Mbps ethernet.
"

Bye,
Skybuck.


They need to make this stuff more complicated.

The "Ethernet" is a single twisted pair with
differential signaling. The real Ethernet in your room,
uses 4 wires (100BT) or 8 wires (GbE) on an 8 contact RJ45.
For the single twisted pair to work, it would have to be
half-duplex or something. The ARC (audio return channel
in SPDIF format) is sent by making both signals in the diff pair,
go up and down together (common mode). If a transformer is use
on the diff pair, it will remove (mostly) the common mode
ARC signal so the device on the other side of the transformer
won't detect the ARC. (It turns out below, they don't
use a transformer, but just AC coupling with capacitors.)

http://pinouts.ru/Video/hdmi_pinout.shtml

I couldn't tell you what the grounding philosophy of HDMI
is. The shield is likely to be a chassis ground thing,
at least on a PC it would be. To work well, that would
require all other devices in the ecosystem to float. And
since those other devices will have switching power supplies,
and would be dumping their "noise" onto the ground prong,
the peripherals could be ground referenced too. Which
isn't the best choice.

I don't really think this would blow anything up, but
then again, electricity in your apartment seems to be
a lot different than the wiring standards here.

When I am unsure about the quality of ground, I run
two devices from a common power strip. (One of those
extension cords with the box on the end with six outlet
holes.) The ground experienced by both pieces of
equipment is then equal. I would use such interconnect,
if running a USB laplink cable between machines (because
the laplink cable is a "violation" of the grounding
principles of USB).

(Common ground for up to six devices...)

https://www.apc.com/resource/images/..._5 00x500.jpg

*******

For the Ethernet to work, it requires a *different* cable.
The Ethernet pair are run as their own diff pair and
the cross-section of the cable is different. The
connectors on the end of the cable are standard,
but how the wires run inside, helps the electrical
scheme work. See the diagram at the bottom of this page.

https://superuser.com/questions/1264...called/1264709

*******

OK, try PDF page 32 here.

https://www.latticesemi.com/-/media/...ument_id=51621

"Fig 6.6 HEAC Interface"

It shows the HEAC pair is AC coupled, so there's no
DC flow. That would basically have as much "exposure"
as any other TMDS pair in the cable. Electrically
isn't any more risky than regular HDMI.

This is the page 32 figure, captured as a GIF.

https://i.postimg.cc/GpwhK1zh/HDMI-Ethernet-Pair.gif

Paul