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 FAQ's

DSL Technology Overview

What is Digital Subscriber Line (DSL)?
How does DSL work?
Can I select an ISP other than NTC to provide Internet access with DSL?
How fast is DSL?
How does DSL support both voice and data on the same line?

 

 Answers

What is Digital Subscriber Line (DSL)?

  1. DSL is a modem technology that turns a customer's existing phone line into a three-channel data delivery system. One channel transmits voice services, so normal phone or fax usage continues whether or not you are accessing the Internet. A second channel transmits data downstream at high speeds, and a third bi-directional channel transmits data upstream. The downstream and upstream channels carry information to and from the Internet. Phone or fax calls occurring on the voice channel are not affected by your online activity occurring on the two data channels.

  2. There are modems at each end of the phone line. One is at your computer, one is in the NTC central office. Working together, they provide a dedicated connection that avoids the need to dial-up for access like with traditional analog modem Internet access. The modem in the NTC central office points your Internet traffic to the DSL network and on to the Internet.

  3. With DSL Internet access, you have a fast connection to the Internet. You just click on the desktop browser icon to get online without dialing-up and - without busy signals like you may get with analog modems.

How does DSL work?

NTC DSL is based on Asymmetric Digital Subscriber Line (ADSL), a super-fast modem technology that can provide data transmission at significantly higher speeds than your standard 56K modem. DSL transforms standard twisted-pair copper telephone wires into a high-speed digital pipe. Since this wiring is already in place in most homes and offices, millions of users can switch to DSL service without the need to run new wires to your location. DSL is designed to take advantage of the portion of the bandwidth not used for voice calls. DSL technology splits your phone line into three information channels. One carries data at high speeds from the Internet to your home computer. Another channel transports data at moderate speeds from your home computer to the Internet. The third channel handles regular phone calls and faxes. You'll be able to surf the Internet while making phone calls or sending a fax. Your regular phone line will continue to work in the event that a power failure affects your computer.

Can I select an ISP other than NTC to provide Internet access with DSL?

No. DSL technology utilizes higher frequency spectrums for data transmissions that are not being used by voice communications. This allows simultaneous analog voice or fax and DSL data transmission over the same telephone line. You still use your phone as you do now.

How fast is DSL?

NTC offers several packages, starting with maximum connection speeds of up to 1Mbps downstream and up to 512Kbps upstream. NTC DSL customers enjoy the ability to download files and surf the Internet at lightning speeds. Throughput speeds experienced will be lower than connection speeds based on factors including the distance between your home and the NTC central office; the condition of your line; traffic on the network and the Internet; and the performance of servers hosting Web sites you visit among other factors.

How does DSL support both voice and data on the same line?

A device called a "splitter" assigns voice and data transmissions to different frequencies. Digital bits travel on the inaudible frequencies of your phone line. That keeps them separate, and that's why all the signals - voice and data - can work in parallel without colliding with each another. A DSL modem spreads signals over many frequencies on the line, carrying many times more information than an analog dial-up modem.

 

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