HDMI-CEC stands for High Definition Multimedia Interface – Consumer Electronics Control. It is a system for controlling multiple devices connected via HDMI; more on later.
The technology was developed and used en masse in HDMI 1.2 or higher ports. To orient yourself, if you have a TV or other device with HDMI ports and it is made after 2006, it probably has HDMI CEC. Although the first HDMI 1.0 standard was designed to use CEC, very often, manufacturers should have paid more attention to this requirement; there were many devices without CEC support in the HDMI ports.
History of HDMI CEC
The Consumer Electronics Control (CEC) system was first introduced in analog devices such as televisions and VCRs, and it operated through SCART connectors. This technology allowed users to control VCRs using their TV remotes, but it was not widely used as not all televisions had SCART connectors, and VCR remotes only had limited functionality. With the advent of HDMI ports, the CEC system was integrated into HDMI, making it an essential feature in all devices that have HDMI ports.
HDMI CEC explained with an example
I will try to explain it as simply as possible: HDMI CEC means that you have several devices, most commonly used as follows: you have a TV, a streaming device such as Roku or Chromecast connected to the HDMI port on the TV, and you have a sound receiver or soundbar connected to a second port labeled HDMI ARC (eARC). So if you enable HDMI CEC on all devices, you only have to turn on one device at a time to turn on all devices, for example, you can tell Alexa to turn on Chromecast, and then the TV and soundbar will automatically turn on. You can then control the streaming device with the TV remote.
How HDMI CEC physically works
To use HDMI CEC, several requirements must be met.
The HDMI cable must support CEC and use a separate wire to carry the signal over the cable. Some cable manufacturers may save money and not make this wire in the cable.
All devices you want to control must support HDMI CEC.
The control is done as follows. When you activate HDMI CEC mode on the devices, the HDMI port remains energized.
Let’s look at an example of turning on a TV with Chromecast. Just turn on the Chromecast; this device generates a control code (Power) and transmits this code to the TV; the TV receives this code and understands the signal to turn on and will turn on the TV. Similarly, in reverse, you turn on the Chromecast TV. Then, if you want to control some device, all signals from the TV will be transmitted via HDMI to the desired device.
For example, if you want to add sound to the soundbar, you take the remote from the TV and press the boost button. The command goes to the TV, and the TV broadcasts this command to all other devices. There is a slight nuance here; both devices will respond if they understand the command. For example, the Chromecast and the soundbar will add sound.
HDMI CEC structure for digital devices
When you enable HDMI CEC support on a device, the added device is connected to a single management bus of up to 15 devices. The new device is registered and assigned a logical address, and its type (TV, player, streaming device, audio device) is specified for proper operation. Since HDMI is primarily a video interface, a TV or monitor will always be selected as the primary device.
HDMI CEC Command Structure
HDMI CEC commands consist of 10 bits. There can be two command blocks; the first block tells which device initiated the command and for which device, and the second block transmits the command for execution.
But if there is no need to address a specific device, just the command block is transmitted; this is the case in most cases.
Example: You have a TV, a Chromecast, and a soundbar, as in the previous example. Regardless of which device you turn on first, the HDMI CEC will send a command from the activated device so that all devices connected to the CEC bus will turn on.
Next, while watching a video on the Chromecast, you want to pause watching. Take your TV remote and press the pause button; the TV generates a command to stop viewing and transmits this command to the bus; in this case, only the Chromecast can respond. Only it can recognize this command. The soundbar does not support this command and will ignore it.
What commands does the HDMI CEC support
The HDMI CEC can support many commands. All commands are assigned a specific code for proper communication. The commands are a list of commands but very conventional.
- Power control commands: Turn the device on and put it in standby mode.
- Commands to control video playback: start, stop, pause.
- Cursor control commands: Select a video through the streaming device menu.
- Audio control commands: audio control.
There are other commands, but they are rarely used in practice.
How to enable HDMI CEC on your TV and other devices
You should know that when HDMI CEC was introduced in 2007, TV sets had little to offer, so the companies’ marketing departments decided to call HDMI CEC support by its name. This allowed customers to present a unique technology when it was common to find TV commercials for Samsung mentioning that the TV supports Anynet + technology. And subconsciously, the consumer thought the TV had something special. This is just an advertisement, but as a result, TV sets have different names for HDMI CEC, but sometimes in brackets, they explain what it is. As a result, this is what HDMI CEC is called in some brands.
- Anynet (Anynet+) – Samsung
- Aquos Link – Sharp.
- BRAVIA Sync – Sony
- HDMI-CEC – Hitachi
- Kuro Link – Pioneer
- CE-Link and Regza Link – Toshiba
- RIHD – Onkyo
- SimpLink – LG
- HDAVI Control, EZ-Sync, and VIERA Link – Panasonic
- EasyLink – Philips
- NetCommand for HDMI – Mitsubishi
To begin using HDMI CECs, you must enable the HDMI CEC setting. Enabling HDMI CECs does not require additional settings. For example, you must find Anynet + on your Samsung TV and turn it on.
Similarly, you need to find and enable the setting on other devices. You need to go to the menu of the corresponding device and find the CEC setting. Since there are so many devices, I will not give you examples.
Problems when using HDMI CEC
What problems may you encounter when using HDMI СEC? You should be aware that equipment manufacturers stipulate the possibility of compatibility problems when using HDMI CEC with different equipment brands. The protocol is the same, but some manufacturers may only partially release some commands, which can cause problems. This can only be checked experimentally.
A second possible problem is using cables that need CEC support. Although by default, if you buy an HDMI 1.4 cable, it should support CEC, there are exceptions. Check the cable for HDMI support on other devices.
You may also run into problems if you are using equipment from different manufacturers and different years, especially if one of the devices is quite old.
How you can use HDMI CEC
HDMI CEC is a useful feature that allows for the control of multiple devices through one remote or device. For example, if you have a TV, Chromecast, and soundbar all connected via HDMI, you can turn them all on by simply turning on the TV.
Another way to use HDMI CEC is if your TV does not support voice assistants like Alexa. If you have a streaming device that can control Alexa, you can turn on the TV by activating the streaming device, which will then turn on the TV through HDMI CEC.
While HDMI CEC is also used in other systems like video surveillance, it is most commonly used on televisions. Overall, HDMI CEC is a convenient and efficient way to control multiple devices with ease.