Digital Distribution

Computer network techniques, specifically those used for the internet, are beginning to provide new ways of distributing information of many types: sound, image - both still and "moving," formatted text like documents, games, and software. Though the protocols were created to help computers exchange data, they work just as well for home entertainment networks.

Digital data transfer works in a way that is distinctly different from older ways of sending an audio or video signal. In "analog" systems, some part of the "carrier" changes to indicate a change in the data. Changes to the carrier's strength (AM) or it's frequency (FM) are the two most common ways of carrying sound and pictures. An AM signal must be strong enough to still be received when it's strength is the lowest. An FM signal needs enough "bandwidth" to carry the lowest and highest frequencies in the data. In contrast, a digitized signal has the same strength and little change in frequency to convey the same information. Rather than representing the changes in the data, a digital signal uses a number to represent "samples" of the data (which are taken often enough that they are meaningful). Each number, in binary, is a string of ones and zeros. They can be sent as signal-high and signal-low. There's hardly any depth of frequency at all. The same bandwidth carries much more data in the new scheme.

It's worth noting that although a distorted analog signal results in distorted music, snow on the screen, or other annoying but tolerable problems, a digital signal has a higher tolerance for noise, right up until the number becomes undecipherable. The data becomes meaningless, and there's no music, picture, or anything else. But the extra bandwidth makes it possible to correct many data errors by having error checks and correction codes. Unlike an over the air broadcast signal, data sent over a network can be acknowledged as being ok or not, so that the sender can resend. This involves breaking the data up into pieces called packets, and the receiver saying which packets were ok and which ones weren't. The rules that describe how the data is broken up, packaged, verified, and put back together again are some of the protocols mentioned earlier.

IP Control

Just as streaming audio (or video) takes advantage of internet protocols to transport music, as digital data, from a source location to a listener somewhere else, similar methods can convey control information from the listener or viewer back to the source. In fact, some of the most versatile remotes are really palm-top sized computers. They have touch-screens, a small operating system like Windows CE, and a stripped-down web browser. When you touch a "button" on the screen, the browser software sends information over a network (often wireless) to a server, just like when you click on a link while surfing the web. When the remote is simpler, the commands that a browser would generate are built into or programmed into the device.

Either way, the server interprets the information, sends a response back to the remote, and performs the action or actions that were specified. Since the command stream (the data) is via the internet, the command string can be as long and as complicated as needed. It doesn't matter if you put the remote down before everything is sent. It doesnt't matter if you're in another room or walking around. You can even control several different devices in different rooms.