ADSL is the perfect high-speed Internet solution for home and small businesses. The following outlines the service so that you can see if DSL is right for you.
What is DSL?
It is an "always-on" internet connection. DSL stands for Digital Subscriber Line. It provides high speed and secure Internet connectivity over existing copper telephone wires.
Is it really so much faster than my dial-up modem?
Yes! With DSL, surfing the web and sending e-mail occurs at almost instant speeds.
Is DSL reliable?
Yes! DSL is a dedicated line.
Will it tie up my phone lines?
No. DSL is always on, but your regular telephone service will remain uninterrupted. Because of this, you can still use your telephone for talking or sending faxes while surfing the Internet. You don't have to dial-up each time you want to check your e-mail or visit a website.
What gives DSL such great value?
Low price, high performance! Before DSL, dedicated high-speed service (such as a T-1 line) could cost over $1000 a month! Customers who didn't need the extremely high reliability of a T-1 solution were left to rely on dial-up connections, dramatically reducing efficiency, effectiveness, and their ability to make money while waiting for downloads of graphic-intensive web pages or e-mails with large attachments. DSL is the answer to this problem, providing affordable, high-speed Internet access at a low monthly cost.
How does DSL compare to Cable Internet services?
DSL is a fast, secure, one-to-one connection. Cable has some inherent drawbacks. First, the cable network is shared, which means as the number of cable users increases, the speed on each individual's line decreases. Second, a shared network is less secure than a dedicated service like DSL, as neighboring cable customer can more easily intercept data or hack into another user's computer.
How DSL works
Original Telephone Technology
- Traditional phone service (sometimes called "Plain Old Telephone Service" or "POTS") connects your home or small business to a telephone company office over copper wires that are wound around each other and called twisted pair. Traditional phone service was created to let you exchange voice information with other phone users.
- The type of signal used for this kind of transmission is called an analog signal. A telephone takes an acoustic signal (which is a natural analog signal) and converts it into an electrical equivalent in terms of volume (signal amplitude) and pitch (frequency of wave change). Since the telephone company's signaling is already set up for this analog wave transmission, it's easier for it to use that as the way to get information back and forth between your telephone and the telephone company. That's why your computer has to have a modem - so that it can demodulate the analog signal (lots of noise) into its digital equivalent (which is what your computer understands).
Limitations of Analog Data Transmission
- An analog transmission only uses a small portion of the available "bandwidth" copper wires are capable of transmitting. The maximum amount of data that you can receive using ordinary modems and analog signals is about 56Kbps.
- The ability of your computer to receive information via phone line is constrained by the fact that the telephone company's equipment filters information that arrives as digital data into analog form only. Your modem must change the signal back into digital. In other words, the analog transmission between your home or business and the phone company is a bandwidth bottleneck.
The DSL Difference
Digital Subscriber Line (DSL) is a technology that assumes digital data does not require conversion into analog form and back. Digital data is transmitted to your computer directly as digital data and this allows the phone company to use a much wider bandwidth for transmitting it to you. Meanwhile, if you choose, the signal can be separated so that some of the bandwidth is used to transmit an analog signal so that you can use your telephone and computer on the same line and at the same time.
Factors Which Affect Data Rates and Availability
DSL modems follow the data rate multiples established by North American and European standards. In general, the maximum range for DSL without repeaters is 5.5 km. As distance decreases toward the telephone company office, the data rate increases. Another factor is the gauge of the copper wire. The heavier 24 gauge wire carries the same data rate farther than 26 gauge wire. If you live beyond the 5.5 km range, you may still be able to have DSL if your phone company has extended the local loop with optical fiber cable.
What Does the "A" in ADSL Mean?
The "A" stands for "asymmetric." This means that the download speed and the upload speed on the DSL connection are not the same. This is a standard configuration. Most Internet activities (such as browsing web pages, reading email, etc.) demand a fast download speed. The upload speed is not critical, since you generally won't be sending vast amounts of data.
Does Everyone Qualify for DSL?
DSL is a technology that is limited by the distance of your residence or business from the telephone company's Central Office and certain devices on the telephone lines. In some cases, a location may be too far from the Central Office, or certain devices on the phone lines may prevent DSL service.
Why Is DSL Distance Sensitive?
DSL is an electric signal that travels over a copper phone line. The physical properties of the copper limit the distance the signal can travel without becoming distorted or faded.
What Is the Distance Limit for DSL Service?
Distance is measured by the length of the cable that twists and turns underground. The limitations are different for the different flavors of DSL. The closer you are to the telephone company's Central Office, the more DSL options you have.
Does a Computer Need to Be Upgraded to Use DSL?
Most new computers come with a Network Interface Card (NIC, or Ethernet card) pre-installed. If your computer doesn't have a NIC, you can purchase one at any computer electronics store. Once the NIC is installed, it provides a jack on the back of the computer allowing the End User to connect your new DSL modem to the computer.