Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: One port is DDC. What is DDC?
Document: Ordered 4 total, 1 to start, then 3 more later. 1st one and 1 of 3 from the second shipment have a major bug, both sender and receiver sides' RJ45 ports are labeled in the same way i.e. "VIDEO" on the left and "DDC" on the right, if CAT6 cables are connected between the sender and receiver according to the labels on the enclosure, it will NOT work at all. The CAT6 cables must be crossed.
I would have assumed that you must connect the video to video and DDC to DDC. I did not connect the power supply to the device. The video looked the same with or without the power supply connected. I am using cat5e cables and generic HDMI cables. My setup is using a DirecTV cable box as my source. I have a 6' HDMI connected to a pass thru keystone wall jack with a 10' HDMI cable connected to the sender unit.
Of course after I ran the cables I realized the 580 has a mini-HDMI port instead of a standard but using a DVI-HDMI adapter worked fine. It even passes through sound without any extra sound cabling (unlike my older 9600 GT). Just ordered a wireless xbox controller for some steam big picture gaming.Pros:-  Only the receiver is powered.-  When the video cables are connected the sending unit has a LED that lights up.
I use this to send an HDMI signal to another room. I split the output of our TiVo using aViewHD 2 Port powered splitterand run the output from that device into this HDMI extender. The Ethernet cables I'm using are 50 ftUltraFlat Cat6which are great for running through walls or under carpet. The remote television supports up to 1080i and the picture on that set is beautiful. I can't tell that it's not hooked directly to the source.My only complaint is the small gap between the receiver and the power supply.
failed after one week. amazon processed a refund very quickly. amazon is great but the product stinks.
We bought two of these to connect projectors at church and both didn't work out of the box. After one month you are stuck with it without a return.
I order two, and only one works, the other didn't work.it light up but dont work, to bad because i was setting up a office screen setup
Tried adapters with multiple cables and they just refused to work.Maybe I just got a bad one, but I'm not going to buy a second to see
You need both ports if you want HD video and sound. Great Product!!! Easy to Install. There is a power adapter that comes with it and you have to power one end so leave room for that in your project.
Otherwise, I was hoping based on other reviews that this model would solve it completely especially considering the short run of 30-feet and that was why I had to dink it one star.
Answer: DDC - Display Data Channel - allows your display to communicate it's display modes to your graphics adapter.