The two digital transitions
The country is beginning to hear about the coming Digital Television transition. Unfortunately, there are continuing areas of confusion, even (as pointed out previously) among experts. One of the key points that trip up people is that there are really two transitions. Let’s make one thing clear up front. If you get television from a cable operator (or one of our competitors), you probably lump all those channels together: CNN, Fox, Lifetime, ABC, it’s all the same, right? But some channels are from broadcast stations in your area: ABC, NBC, CBS, Fox, The CW. Those other channels, such as MTV and ESPN, are cable channels. The high-profile DTV Transition coming in February 2009 — as full power over-the-air broadcast TV stations switch to digital and turn off their analog broadcast signal — is the broadcast industry’s digital transition. And although cable is playing a role in that, the cable industry is going through its own transition. Let me explain the difference.
The broadcasters’ transition is about digital television, where the picture and sound information is expressed in the form of data bits representing, for example, a “1” or a “0”. You can think of this transition as analogous to the transition from vinyl records to CDs.
Cable operators are also transitioning some analog channels onto digital cable tiers in order to reclaim space. With digital cable, compression technology is used to allow more than one program service to be carried in the bandwidth space normally required for one analog program service. Typically, the signal is sent to the home, decompressed in the set-top box and changed into analog signals for display on the television. You can think of this transition as something like the manner in which you can compress large files for easier downloading, and then you decompress them for viewing.
Your local TV stations are offered in hi-def formats on digital cable, but digital TV and digital cable are two different animals.
As we’ve discussed before, part of the DTV Transition will require that you get a digital-to-analog converter box to continue watching full power over-the-air broadcast TV stations on an analog TV set. If all your TV sets are connected to cable, you won’t need to do anything to continue to watch your local broadcast stations.
However, some popular cable channels are only available on cable’s digital tiers. In addition, other popular cable channels may be moving from the analog tier to the digital tier because channel space is limited. In these circumstances, you may want to move up to digital service from your cable company — and a digital cable set-top box. But don’t confuse cable’s digital migration with the broadcasters’ digital TV transition.