FAQ - DSL
What is DSL?
DSL stands for "Digital Subscriber Line," a broadband technology that uses telephone lines and digital coding to create a connection to the Internet from your computer. That link can carry vast amounts of voice, video and data information at very high speeds.
How does DSL work?
DSL service providers use the same copper-based lines that let you make and receive telephone calls. To send data at high speeds:
- Carriers use the lines' higher frequencies that telephone service doesn't need.
- DSL modems are hooked up at both ends of a telephone line -- one at the business, the other in the nearest telephone company switching station.
- The modems digitally divide your telephone line into three channels: One handles telephone traffic, one handles upstream data from your computer to the Internet, and the third handles downstream data traffic from the Internet to your computer.
I understand that there are several forms of DSL service. What are they?
ADSL (Asymmetrical Digital Subscriber Line) is designed primarily for the residential consumer market. The "asymmetric" means that the connection transmits data at faster speeds downstream from the Internet to your computer than upstream from your computer to the Internet. The reason: DSL users rarely upload the same amounts of data as they download. ADSL can support speeds up to 8 megabits per second (mbps) downstream and up to 1 mbps upstream, although the connection rarely approaches those marks.
IDSL (ISDN Digital Subscriber Line) also offers equally fast downstream and upstream speeds, but it's pegged at 144 kbps.
SDSL (Symmetrical Digital Subscriber Line) offers similar upstream and downstream speeds ranging from 385 kbps to 2 mbps.
I sometimes see the term "xDSL." What's that?
It's a generic term for all forms of DSL service spanning transmission speeds from 128 kbps to 52 mbps.
What are DSL's major advantages?
It's fast. It's always on. It doesn't tie up your telephone while you're online as a so-called "dial-up" service does. And it won't interfere with caller ID, call waiting or other telephone features.
How fast is a DSL connection?
The technology can deliver data ranging from 128 kbps to 7.1 mbps. That's from six to 125 times faster than the standard dial-up connection's speed of 28.8 or 56 kbps. With a DSL broadband connection, you can:
- Download huge files from the Internet in a fraction of the time it takes a dial-up service.
- Move from Web site to Web site as if you were changing the channels on a TV set.
- Access a growing range of news, entertainment and information resources, including specialized services being developed expressly to take advantage of broadband's blazing speeds.
What does "always on" mean?
Once you've turned on your computer and clicked on your DSL connection to the Internet, that link stays on as long as your computer does. There's no need to dial a telephone number and then wait for your modem to connect you to the Internet -- often a time-consuming, frustrating exercise -- every time you go online.
An always-on connection lets you hop on and off the World Wide Web whenever you want with no delay; send an e-mail at a moment's notice; or access vast databases at the flip of a switch.
What are DSL's biggest drawbacks?
Probably the biggest one is the fact that it's not available everywhere, due to the technology's limits. Copper lines can carry data using DSL's high frequencies only so far -- say, three miles. Beyond that, the quality of the transmission erodes. That's why DSL service carriers say prospective subscribers must live or work within 12,000 feet or so of a telephone company central office (CO) to get a DSL link.
What kind of equipment do I need?
A DSL modem — commonly called a "router" — that's usually leased from IDC Global and included in your monthly bill. Your computer also must connect to the router, which is done through an Ethernet cable that is usually provided. To transform a telephone line into a high-speed data line, DSL equipment must be installed on both ends of the line — at the customer premises and the local telephone central office.
Can I use more than one computer on my DSL line?
Yes, but you'll need unique High Speed Internet User IDs and passwords for each computer if they're used at the same time. Be aware, also, that using more than one computer at a time probably will slow download speeds.
Should I worry about security issues with a DSL connection?
It depends on the level of trust you operate at in other areas of your life, your comfort level with technology, and the kinds of information you keep on your computer. Generally, it pays to take a few precautions — the online equivalent of locking your front door — to keep intruders at bay.
What precautions can I take?
- If you have a Microsoft computer, turn off the file-sharing function.
- Get a good anti-virus program and have it scan your computer each week.
- Don't run a program or open an e-mail attachment without first running a virus scan.
Anything else I can do?
You might consider a firewall. It monitors your Internet connection and refuses to let anything suspicious into your computer. Hardware firewalls are boxes that you plug your computer into. Software firewalls are programs that you download from the Internet to your computer. These applications scan for hackers, just as anti-virus programs look for bugs that can disable your PC.