How Does DSL Work?by Tiesha Whatley
What is DSL?
DSL, Digital Subscriber Line, is a high-speed way to connect to the Internet through regular phone lines. Many people are finding advantages to DSL as opposed to the regular dial-up through a modem. For one, DSL doesn't tie up the phone line; you are able to stay connected to the Internet while talking on the phone. Long gone are the worries of being "kicked off" the Internet every time a call comes through. Another advantage to DSL is the speed at which web pages are loading; downloading and uploading times are exponentially reduced. Signing up for DSL is quite easy. There isn't any additional installation of cables and phone lines. There also isn't any pricey equipment to purchase either; the DSL company sends all the equipment needed for their service. Being able to receive DSL service isn't as easy as setting it up, though. Depending on the area that you live in, you may not be able to receive the service or get a very poor DSL service.
How DSL Work?
The way DSL works, and the reason why you can have it over your regular phone line, is by splitting the frequencies found in the phone line into two bands. The bands have a high frequency and lower frequency. The higher frequency (25 kHz or higher) carries the DSL service while the lower frequency (4 kHz or lower) carries the phone service. To avoid interference for each of the frequencies, filters are usually used on each phone in the house and not just the line to which the DSL equipment is connected. To make a regular phone line capable of carrying DSL, certain provisions have to be made to the local loop of the public switched telephone network. There are several different channels that were already available through the phone line but weren't being used. DSL uses these channels to continue to loop information through any available channel then go to the next one once the current one is in use.
Connecting the Equipment
The physical connection of the DSL equipment is fairly simple. Filters are connected to each phone line in the location that DSL service is being set-up. Through a regular phone cord, the DSL Transceiver, or modem, is connected and receives the higher frequency. The filter has two slots; one for the modem and the other for the phone. The modem is then connected to the computer with either an Ethernet or USB cable. Depending on the ISP, additional software may needs to be installed. There are several checks that the DSL Transceiver must perform before DSL service is viable on your computer. For one, it makes sure that power is being supplied to the modem. The next check is for Internet service; this checks that the account is active from the ISP (Internet Service Provider). The next check is for DSL service; this checks the strength of the DSL signal and makes sure that it is efficient for you to connect to the Internet. All of these checks returns a "go ahead'" and displays this to you either through lights on the front of the modem or the connection software that came with the modem. Other checks may include checking to see if the modem is connected to the computer through the USB or Ethernet cable. If you have wireless service, the modem also checks for the wireless connection.