When it comes to starting using an HDMI cable, compatibility is one of the main concerns. Nowadays, there are many types of HDMI cables on the market: Passive Copper HDMI Cable, Active Copper HDMI Cable, and Active Optical Fiber HDMI cable. Regardless of the types you choose, most of us have a hard time trying to solve the compatibility issues.
Compatibility problems are related to two different systems, not being able to properly operate together. In simple words, a cable working with an HDMI device may not function with another device of the same kind.
In this article, we will give you some advice on how to solve HDMI cables compatibility issues by giving you more information about DDC, EDID and HDMI AOC cables.
Before talking about how to solve HDMI cables compatibility issues, let’s understand the difference between DDC and EDID. In most cases, when HDMI cables have compatibility problems during data transmission, it happens because of DDC.
The Display Data Channel (DDC) is a defined standard by VESA (Video Electronics Standards Association). It describes a physical connection between a display and a video card. The connection is finalized to the transmission of data identification and the screen video specifications. The DDC is a channel to send information such as the resolution, gamma values, and scanning frame to the monitor.
Among the different options, the physical connection can be guaranteed by HDMI cables. According to HDMI definition, all receivers must support the enhanced DDC defined by VESA ENHANCED DISPLAY DATA CHANNEL STANDARD Version 1. This version complies with the I2C standard, which means that data must be synchronized with SCL. The HDMI source side uses the I2C interface to read and receive E-EDID.
The standard HDMI interface has the function of hot plug detection, whose pin19 is the HPD signal. The hot plug detection allows the HDMI transmitter to judge whether the interface is connected to the HDMI display device.
HDMI devices use the signal Voltage to trigger the E-EDID reading. The signal drive low-level voltage should be of 100ms, and low-level output voltage within 0.4V.
To solve HDMI cables compatibility issues, we also need to know more about E-EDID. The real data that is exchanged between the screen and the graphic adapter is called EDID. The enhanced version, the E-EDID (Enhanced Extended Display Identification Data) is a VESA standard data format.
E-EDID must follow VESA E-EDID Standard Release A, Revision 1，and it both supports EDID 1.3 and EIA/CEA-861B.
The E-EDID includes basic information about a monitor and its capabilities: the display size, manufacturer, native resolution, color characteristics, frequency range limits, and more. Once this information is received, they can subsequently generate the necessary video characteristics to match the screen requirements.
Ultimately, E-EDID is a VESA standard data format used to communicate with the system via a DDC. To put it in simple terms, DDC is a road, while EDID is the information going through this road.
HDMI AOC Solution
A recommendation to solve HDMI cables compatibility issues could be using HDMI AOC. HDMI Active Optical Cable (AOC) is also a type of HDMI cable. It follows the HDMI standards and has the same requirements on the signal transmission system.
An example that has recently received high praise for its reliability is Smartavlink HDMI AOC cables. With its advanced optical engine, this new type of HDMI cables can provide full HDMI signal integrity without signal loss, delivering crystal clear digital images instantly. Up to 100m Maximum Length, it sees its application in TV broadcast station, conference room video equipment, airplane on/board video system, security systems, and much more.
Smartavlink started with HDMI AOC development over seven years ago. They have a rich DDC/EDID/I2C application experience in designing HDMI AOC. Smartavlink HDMI AOC is among the most competitive long reach HDMI interconnection solution on the market. The Company with its wide range of products provides OEM/ODM solution worldwide.
If you are interested in finding out more about how to solve HDMI cables compatibility issues, Smartavlink will be happy to assist you.