Why pin 2 missing in these HDMI adapters? - AVS Forum
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post #1 of 18 Old 07-06-2014, 08:56 AM - Thread Starter
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Why pin 2 missing in these HDMI adapters?

On a quick look, all the adapters of this kind on eBay are missing pin 2 (seems to be Data2 shield). Any idea why?
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post #2 of 18 Old 07-06-2014, 12:46 PM
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Originally Posted by shae View Post
On a quick look, all the adapters of this kind on eBay are missing pin 2 (seems to be Data2 shield). Any idea why?

That is pin 18, not 2. Your picture is of a plug, not a receptacle. It is a 5v pin, missing in many circuits.


http://www.hdmi.org/installers/insidehdmicable.aspx
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post #3 of 18 Old 07-06-2014, 12:52 PM - Thread Starter
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Thanks. What uses it in practice? And why would it be missing, to save a quarter of a cent?
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post #4 of 18 Old 07-06-2014, 12:59 PM
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Perhaps to preclude the source being used as a power supply?
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post #5 of 18 Old 07-08-2014, 02:00 AM - Thread Starter
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I don't think it's the business of a simple physical adapter to decide what the connected devices should or shouldn't do.
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post #6 of 18 Old 07-08-2014, 07:37 AM
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You can probably find a comparable adapter from another vendor that has the full compliment of pins that you desire/require.

Or... just contact the EBay vendor of that particular adapter and ask them.
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post #7 of 18 Old 07-08-2014, 12:23 PM
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Quote:
Originally Posted by Ratman View Post
You can probably find a comparable adapter from another vendor that has the full compliment of pins that you desire/require.

Or... just contact the EBay vendor of that particular adapter and ask them.

Hmm...I wonder why HDMI's parent site (HDMI.org) shows that pin missing in its cable diagram?


http://www.hdmi.org/installers/insidehdmicable.aspx
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post #8 of 18 Old 07-08-2014, 12:43 PM
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Quote:
Originally Posted by shae View Post
I don't think it's the business of a simple physical adapter to decide what the connected devices should or shouldn't do.
The entire purpose of HDMI was to enforce the HDCP protocol by licensing. "The industry" didn't want to see an open source plug like DVI become the standard.

Sorry, but I'm sure you too have never seen an HDMI "Record IN" jack

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post #9 of 18 Old 07-08-2014, 01:02 PM
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Quote:
Originally Posted by domino92024 View Post
Hmm...I wonder why HDMI's parent site (HDMI.org) shows that pin missing in its cable diagram?
Golly! I don't know! Contact HDMI.ORG and ask them to explain.

Maybe it's just bad lighting.

Last edited by Ratman; 07-08-2014 at 01:07 PM.
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post #10 of 18 Old 07-08-2014, 03:36 PM - Thread Starter
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So that's the key to defeating HDCP: the missing pin 18!

And asking Chinese eBay sellers on the items they sell will likely result in:

"Hi friend, I don't know, I only paste the description from the supplier. I don't even have the items available directly to me so I can't check."
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post #11 of 18 Old 07-09-2014, 04:07 AM
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Junk...don't buy it.

http://www.hdmi.org/learningcenter/kb.aspx?c=6#68

Quote:
The HDMI specification requires all source devices to provide at least 55mA (milliamps) on the 5V line for the purpose of reading the EDID of a display.
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post #12 of 18 Old 07-31-2014, 09:23 PM - Thread Starter
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I got one of these adapters. Looks like the pin isn't missing, it's just recessed further in. I guess it's supposed to connect last.

But there's another problem: the adapter sticks out too much because of that L shape. I didn't find so far a more compact version.

Last edited by shae; 07-31-2014 at 09:54 PM.
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post #13 of 18 Old 08-01-2014, 05:31 AM
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post #14 of 18 Old 08-01-2014, 09:15 AM - Thread Starter
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Thanks. The L-shaped ones are exactly like the one I have, the rest aren't better. I found on eBay more compact adapters from HDMI Micro (D) to normal HDMI, as well as HDMI male/male, but not male/female. It's a conspiracy.
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post #15 of 18 Old 08-01-2014, 10:26 AM
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Yeah... well, good luck and keep looking.
https://www.google.com/webhp?sourcei...20port%20saver
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post #16 of 18 Old 08-01-2014, 03:58 PM
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Quote:
Originally Posted by speedlaw View Post
The entire purpose of HDMI was to enforce the HDCP protocol by licensing. "The industry" didn't want to see an open source plug like DVI become the standard.

Sorry, but I'm sure you too have never seen an HDMI "Record IN" jack
There are many devices with HDMI inputs. Some even HDCP compliant like video processors and scalers.

There are also HDMI capture cards and USB3 interfaces. But of course these don't support HDCP. Some pro (not broadcast) video cameras use HDMI.

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post #17 of 18 Old 08-02-2014, 06:00 AM
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Quote:
Originally Posted by speedlaw View Post
Sorry, but I'm sure you too have never seen an HDMI "Record IN" jack
Err - I'm sitting looking at one now. My BlackMagic Ultrastudio Express has both HDMI and HD-SDI inputs for recording, and outputs for replay.

It's a common requirement to be able to record the HDMI output from cameras and camcorders - particularly those which don't have HD-SDI outputs. The popular Convergent Nanoflash (which arguably created the sector) and current Odyssey 7 both have HDMI inputs as well. People use external HDMI recorders to record at higher quality (say ProRes or DNXHD) than the internal recorders of some cameras which may use poorer quality codecs like AVCHD. This can often allow you to record 4:2:2 rather than 4:2:0, or to record at higher resolution.

For example, the current Sony A7s is a 4K camera which has stellar low-light performance, and will output a 4K 4:2:2 signal, but will only record 1080p internally. There are plenty of reasons to have HDMI "Record In" jacks...

And the other widespread use for HDMI "Record In" is to allow gamers to record their gameplay.

(Of course this has nothing to do with HDCP - as the cameras and camcorders have HDMI outputs without HDCP)
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post #18 of 18 Old 08-04-2014, 04:13 AM - Thread Starter
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Originally Posted by Ratman View Post
Yeah... well, good luck and keep looking.
https://www.google.com/webhp?sourcei...20port%20saver
Thanks. I think I'll have to wait until a new supplier starts feeding all the Chinese eBay sellers.
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