HDMI connection - straight, cross, odd?

[Artlav]

It's probably an obvious-answer question, but i couldn't google a definite answer to it.
How do you connect an HDMI output and input together, on signal level?

I got on a board an HDMI switch chip and a HDMI->LCD chip. Normally each of them are connected to n HDMI socket and they are linked with a cable.
But being on the same board, i'm just linking them directly.
That is, TMDS Data2+ to TMDS Data2+, TMDS Data2- to TMDS Data2-, and so on.
Is that the right way to connect them?

[Artlav]

Ok, i've realized i can just plug in the cable and probe it. 
Apparently all the lines are connected one-to-one.

[jbb]

All hail the continuity tester!
(It has saved my ass many times.)

[wraper]

HDMI is always straight.

[langwadt]

It's probably an obvious-answer question, but i couldn't google a definite answer to it.
How do you connect an HDMI output and input together, on signal level?

I got on a board an HDMI switch chip and a HDMI->LCD chip. Normally each of them are connected to n HDMI socket and they are linked with a cable.
But being on the same board, i'm just linking them directly.
That is, TMDS Data2+ to TMDS Data2+, TMDS Data2- to TMDS Data2-, and so on.
Is that the right way to connect them?

I think so, but maybe adding a DC blocking cap is not a bad idea.
So, TMDS TX--CAP--TMDS RX for all HDMI/DVI signal pins.

HDMI/DVI is meant to be DC coupled

[wraper]

It's probably an obvious-answer question, but i couldn't google a definite answer to it.
How do you connect an HDMI output and input together, on signal level?

I got on a board an HDMI switch chip and a HDMI->LCD chip. Normally each of them are connected to n HDMI socket and they are linked with a cable.
But being on the same board, i'm just linking them directly.
That is, TMDS Data2+ to TMDS Data2+, TMDS Data2- to TMDS Data2-, and so on.
Is that the right way to connect them?

I think so, but maybe adding a DC blocking cap is not a bad idea.
So, TMDS TX--CAP--TMDS RX for all HDMI/DVI signal pins.

HDMI/DVI is meant to be DC coupled

Yep, if you add capacitors, it will stop working. HDMI transmitter is only able to push down, pull up is provided by HDMI receiver.

[Leo Bodnar]

Yep, if you add capacitors, it will stop working. HDMI transmitter is only able to push down, pull up is provided by HDMI receiver.

This diagram has no 50R termination on TX side.  How is it going to work with Gbps signals?
Leo

[wraper]

Yep, if you add capacitors, it will stop working. HDMI transmitter is only able to push down, pull up is provided by HDMI receiver.

This diagram has no 50R termination on TX side.  How is it going to work with Gbps signals?
Leo

HDMI/DVI normally has no termination on TX side according to specification. Now recalling you sell HDMI lag tester, it's really strange to hear from you.

[Leo Bodnar]

HDMI/DVI normally has no termination on TX side according to specification. Now recalling you sell HDMI lag tester, it's really strange to hear from you.

It's complicated... We have an AC-coupled design that we use for 4K HDMI signal.  There is also an offical thing called "AC-coupled HDMI". I have not really researched in details how it works but I will now.  I have a suspicion that HDMI market quietly moved on to have TX-terminated side too.

This diagram is "conceptual" and has been dragging along since DVI and 25MHz dot clock days. 
With 600MHz rate and rubbish cables I don't believe the termination is now purely on RX side.  Leaving TX high impedance (essentially open circuit if drivers are true current source switches) would be suicidal for HDMI source manufacturers.  (This is my opinion - not a fact.)

The first thing I am going to do tomorrow is throw all HDMI sources I can find on the signal integrity rig and see if there is any signal present with no Rx side pull-ups.  This will show whether this diagram is "conceptual" or still used as shown. It is still there in HDMI 2.1.

Leo

[wraper]

It's complicated... We have an AC-coupled design that we use for 4K HDMI signal.  There is also an offical thing called "AC-coupled HDMI". I have not really researched in details how it works but I will now.  I have a suspicion that HDMI market quietly moved on to have TX-terminated side too.

As I understand from briefly reading that datasheet, it's basically HDMI over DP++ to HDMI level shifter.
From the datasheet:

8.3.8 Transmitter Impedance Control
HDMI2.0 standard requires a source termination impedance in the 75 to 150 range for data rates > 3.4Gbps.
HDMI1.4b requires no source termination but has a provision for using 150  to 300  for higher data rates

[Leo Bodnar]

Sorry, I have not yet had time to investigate thoroughly - my test jig does not have easily updatable EDID memory to make sources output various video modes.  I have seen both signal and no signal with no sink pull-ups. It's inconclusive at best at the moment.
This is of academic interest so not too high on my priorities list.
Leo