How Does DSL Work?
Traditional phone service, sometimes referred to as "Plain Old Telephone Service" (POTS), connects your home or small business to a telephone company office via copper wires. These wires are wound around each other in "twisted pairs". This enables you to exchange voice information with other phone users. The type of signal used for this kind of transmission is called analog. An input device, such as a phone set, takes an acoustic signal and converts it into an electrical equivalent in terms of volume and pitch. Since the telephone company's signalling is already set up for this analog wave transmission, it's easier to use that as the way to get information back and forth between your telephone and the telephone company. This is the reason why your computer must have a modem! The modem receives and translates the analog signal, and then converts the analog values into digital information.
Analog transmission only uses a small portion of the available amount of information that could be transmitted over copper wires. As a result, the maximum amount of data that you can receive using ordinary modems is only about 56 Kbps, a fraction of what is possible when using DSL. The ability of your computer to receive information is held back by the fact that the telephone company filters information that arrives as digital data, puts it into analog form for your telephone line, and requires your modem to change it back into digital. The result is slow downstreaming.
So, you see, modern science came up with a technological solution to all this - DSL! DSL is a technology that assumes that digital data does not have to be changed into analog form and back. Digital data is transmitted to your computer directly as digital data. This allows the phone company to use a much wider bandwidth for transmitting it to you. The signal can be separated so that some of the bandwidth is used to transmit an analog signal; The result? You can talk on the phone and use the Internet on the same line, and do both things at the same time!
What's a Splitter? And Will I Need One?
A splitter is a frequency filter that separates the high frequencies used for sending data upstream and receiving downstream data from the low frequency range used for voice. These high and low frequencies are transmitted at the same time. Most DSL technologies now require that a splitter be installed at a home or business. So, generally the phone company has to make a visit to install it. And, of course, you've gotta be home for the installation! It is, of course, worth the inconvenience and the small additional expense. However, with DSL Lite now currently on the market, it is now possible to manage the splitting remotely from the telephone company's central office. This is known as "splitterless" DSL, "DSL Lite," G.Lite, or Universal ADSL, and has recently been made a standard. G Lite eliminates the POTS splittter, but still does require the installation of a small filter device next to every POTS device (telephone, fax, or modem) sharing the G. Lite line.