Ddc ci in monitor

DDC (Display Data Channel) is a special interface created in order to transmit information between a PC and a monitor.

There are several main varieties: DDC 1, DDC 2B and DDC2A / B.

So what exactly is DDC CI?

DDC 1 is designed to exchange information unilaterally from the screen to the PC. Usually contains information about the screen and its parameters. This encoding is standard for older models and was very common until newer technologies replaced it.

DDC 2B provides two-way transmission of information from a monitor to a computer, and from a PC to a monitor. Differs from DDC 1 of an additional information transmission line of one of the command systems (DID, ExtEDID, VDIF)

DDC 2A / B is similar to the previous one, but is based on a different interface and provides a higher data transfer rate.

There are several standards for transmitting information, the main ones: VGA and VESA DDC / CI. This article will discuss the second format.

Display Data Channel Command Interface (DDC / CI) this technology generates and sends information to the display, as well as receiving response information. The general encoding and instruction set are standards and are described in the MCCS technical documentation. The information on this documentation is closed, but the ACCESS.bus documentation exists for general use. Specifications Version 3.0 which sets out the device and a list of commands, as well as their capabilities and functions application.

What is DDC CI for?

The main function of the DDC is the transmission of image parameter information. This is necessary to debug the picture and adjust the screen modes depending on the computer connected to it. This function provides two-way transmission of information, both from a computer to the screen, and from a monitor to a PC, which allows for the management and debugging of two devices simultaneously.

In order to make the setup more comfortable, there are various utilities that allow you to control the monitor through the channel of information transfer.

One such program is ddccontrol. It provides the user with several basic features, such as:

• Adjust brightness and contrast. What does these parameters change in hardware on the screen itself (by changing the backlight). Also for the user there is the possibility of changing the color scheme.

Important! Changing the brightness of the backlight is possible only if there is such a function in the screen itself.

• The ability to switch between different operating modes on the screen. Be it a preset movie \ game \ user \ text and others.
• Change the language setting. Including those languages ​​that are not available for this region.
• Lock any buttons on the device. Including the button responsible for turning on and off.
• The ability to remotely turn on and off the monitor.
• The ability to move the image.

Also, thanks to this utility, many possibilities are opened for the user. which were not reflected in the instructions or other documents, and the possibility of their inclusion using the control buttons on the device itself was not. For example, the inclusion of the Japanese language in the settings, which is impossible in the European region.

Important! In order for all these functions to be available, the user needs to make sure that the monitor supports DDC / CI.

How to configure DDC CI

In order to use all the functionality that DDC CI technology provides, the user needs to run the ddccontrol utility. Then load the required module: modprobe i2c-dev.

After that, the user needs to find the connected monitors. After the search, their list will open, as well as parameters and functionality.

Attention! There are models of devices that are not in the database of this utility. In this case, the user needs to independently look for options in the registers.

Below is a list of basic commands for functions.

• ddccprobe –d dev: / dev / i2c-2 This command displays a list of all possible commands for the monitor, if this device is in the database.
• ddcontrol –r 0xf5 –w 1 dev: / dev / i2c-2 Menu blocking command. After –w 1 - lock the menu, –w 0 - unlock the menu.
• -r 0xCC –w 0 dev: / dev / i2c-2 Set the menu language. For 0 - Chinese, 1 - Japanese, 2 - English... 9 - Russian.

Important! In manual monitor settings, there may be no settings in Chinese or Japanese.

• -r 0xEE –w 55 dev: / dev / i2c-2 This command allows you to shift the image. A feature of this feature is that it allows you to perform this action on any connection, not just VGA.
• -r 0xdc –w 2 dev: / dev / i2c-2 Set the Internet mode. –R 0xdc register for the message. –W command, which takes values ​​from 0 - user to 5 - movie.

Differences ddc ci in different operating systems

To control the screen, there are a variety of applications, both from the manufacturers themselves and from third-party developers.

The most universal solution to the management issue is the ddccontrol utility. It is universal on both Windows and Linux; it also provides the greatest functionality even with devices that are not in the database.

Separately for Windows users, Samsung has released the magic tune application. This program allows you to manage screen settings, its interface is simple and straightforward. But this program has a major, and obvious, flaw. It only works with devices from Samsung, which reduces its functionality.

LG also has similar programs - forteManager (exclusively for Windows), as well as NaViSet from NEC / Mitsubishi. The latter is not only on Windows, but also on MacOS X.

For users of the operating system from Linux, there are several programs from third-party developers. These are: Linux DDC / CI Tool, Linux DDC / CI control and DDCcontorl. The latest program has not been updated since October 2006, and the development status is unknown.