HDMI logo – This changes everything! (Part II)

In part I of this series we introduced the High Definition Multimedia Interface (HDMI). This article delves into the features and functionality of the 2-way communication capabilities of HDMI, and illustrates how this feature will significantly benefit consumers.

The part of the HDMI specification that will have the biggest impact on consumers is the Consumer Electronic Control (CEC) specification. CEC is a technology that will allow components in a system to discover and communicate with one another. With this feature, consumers will be able to purchase a new component or even a complete system, hook it up, and enjoy their home entertainment system, without having to learn about the inner workings of the equipment. You just plug and play!

CEC will simplify hooking components together by using a technique that has been around for some time, known as a handshake. You have been using technology that uses the handshake technique without even knowing it. Computers use the handshake technique all the time to figure out how fast to send / receive information. If you have had the misfortune of answering your voice line when a fax machine calls, that is another (less sophisticated and painful) kind of handshake using DTMF tones. A handshake is just a communication protocol that devices use to inform other devices of its capabilities. When you get your new CEC enabled HD DVD player and connect it to your CEC enabled HDTV using an HDMI cable, the conversation would be something like this:


Hello, any CEC enable devices out there?


Hello, I am Sony KDS-Z60XBR5 HDTV, my display and audio capabilities are.....


Cool, I am a Toshiba HD-A35 HD DVD, I will send you a 1080p video signal, and...


Great, I can handle all of your audio and video signals; here is my power-on signal code and all of my remote control codes.


Thanks, here is my power-on code and my remote control codes...

At the end of the handshake process, the new component will be aware of the capabilities and the signal codes to send up the wire to all CEC enabled devices it will interact with in your system, and vice-versa.

The benefit of all of this 2-way communication to consumers is that device and system operation is greatly simplified. With CEC features like “One Touch Play” --- when you push one button on your remote, the HDTV changes its signal source to the HDMI input that the Blu-ray player is connected to, the player begins playing the movie, and the AV Receiver is switched to the appropriate input and surround sound signal processing. There is little or no need for user configuration; the components can control and configure each other. One touch play can work without the remote too; the act of putting a DVD in the drawer and closing the drawer, will be enough to have a HDTV and AV Receiver go from standby to on, and trigger a chain of events that will allow you to watch the movie --- optimum sound and picture quality happens automatically. Fast forward a year or two down the road when you change a component in your system, (perhaps a new 1440p Ultra HDTV), you just plug and play, and all your existing functionality plus the added functionality of your new component is there. You don’t have to know anything; the intelligence is built into the components.

The other features enabled by the CEC specification in version 1.3a are:

  • One Touch Record - Allows you to record whatever it is you are seeing on the HDTV screen to a selected recording device. For those of us old enough to remember trying to record TV programs with a VCR, only to find out later that we had the VCR on the wrong channel, this is a welcome feature.
  • System Standby - Enables you to switch all devices to standby mode with the press of one button.
  • Tuner Control - Allows a component to control the tuner of another component.
  • Timer Programming - Allows you to take advantage of the Event Programming Guides (EPG) that are built into many HDTVs, Satellite and Cable set-top-boxes, to program the timer in recording devices like DVRs.
  • Deck Control - Allows a component to interrogate and control the operation (play, pause, rewind etc), of a playback component (Blu-ray or HD DVD player or a Camcorder, etc).
  • Device Menu Control - Allows a component to control the menu system of another component by passing through the user interface (UI) commands.
  • Remote Control Pass Through - Will significant simplify the operation of complex multi-room systems. This feature allows remote control command to be passed through to other devices within the system.
  • System Audio Control - Allows the volume of an AV Receiver, Integrated Amplifier or Pre-amplifier to be controlled using any remote control from a suitably-equipped device(s) in the system.

All products using HDMI are required to pass mandatory testing to ensure compliance with the standard. The vast improvement in the signal quality, component intelligence and the accompanying simplicity of HDMI connectivity, will allow consumers to purchase products with HDMI version 1.3a connections with complete confidence in the end-to-end performance and interoperability of their systems; right? Well, almost! Many features (most notably the aforementioned CEC features) of version 1.3a are optional. System manufacturers are not required to implement the full feature set of HDMI 1.3a to be compliant. Consumers therefore, must shop for features not for HDMI version compliance when making a buying decision. By fear not, help is on the way in the form of SimplayHD. We will take a look at SimplayHD in the next instalment of this series.