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How Switched Digital Video Works

Switched Digital Video Advantages and Disadvantages

Switched digital video systems' most obvious advantage is that they address one of the biggest problems cable companies have -- running out of bandwidth. As more people sign up for HDTV services, high speed cable modems and VOD, cable companies have to find a way to deliver. An SDV system helps cable companies implement a solution without replacing miles of cable, since the system can work on top of an existing infrastructure.

Increased bandwidth can also lead to more services. A cable company could choose to increase the number of channels it offers, allowing it to compete more effectively with satellite television companies. Additional channels could include more HD feeds or programming catered to a particular region.

Cable companies provide Internet access in much the same way they provide television feeds. Companies feed Internet downstream through 6-megahertz (MHz) channels in the cable bandwidth. Upstream feeds, the information sent back through your modem to the Internet, goes into a 2 MHz channel. When customer demand gets heavy, the cable company creates a new 6 MHz channel to relieve stress on the system. With SDV, cable companies have more bandwidth available to convert into Internet channels during periods of high customer demand.

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A switched digital video system sends only the channels requested by viewers, saving the cable provider bandwidth. Click play to learn more.­

SDV systems provide some options that are more important to the cable company than the consumer. Using SDV systems, cable companies can get more information about what their customers watch -- most SDV systems preserve individual customer privacy, but they still allow cable companies to see which channels are in high demand in various regions. Some SDV companies offer systems that would allow a cable company to target specific regions, or even specific households, with local advertising based on viewing habits. That can be a powerful bargaining chip when the cable provider meets with potential advertisers, though consumers might not be as thrilled about it.

Increased bandwidth could also let cable companies offer more interactive options. Let's say you've decided to order a boxing match pay-per-view special. The cable company could process your request and send you a message that gives you the option to order pizza from a local restaurant. You use your remote control to navigate a menu, choose your pizza and toppings, and confirm your order. Half an hour later, you're watching the pay per view and enjoying a hot pizza pie.

The biggest disadvantage to SDV systems is that there are many components in the system. This means that when problems arise, cable companies might find it difficult to figure out the source of the issue. Problems could start in any section of an SDV system's architecture, and different problems require different solutions. Problems originating from the customer's STB will only affect that one household, but a problem with an SDV server or SRM has the potential to affect thousands of customers and might require teams of technicians to get it back on track. In many cases, cable companies will have to rely on products from multiple vendors to create one SDV system. Some products may have compatibility issues with others, making it challenging for cable companies to deliver reliable service. Even so, SDV systems are an attractive alternative to replacing fiber-optic and coaxial cables with higher capacity lines.

In the next section, we'll take a look at some markets that have SDV systems in place.