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FCC CONSUMER FACTS Produced Jointly By: Office of Engineering and Technology · Consumer & Governmental Affairs Bureau
Federal Communications Commission
445 12th Street SW, Washington, DC 20554
1-888-CALL-FCC (voice)
1-888-835-5322 (TTY)
www.fcc.gov/cgb
Broadband Access for Consumers
What is Digital Subscriber Line (DSL)?
- Digital Subscriber Line is a technology for bringing high-speed and high-bandwidth, which is directly proportional to the amount of data transmitted or received per unit time, information to homes and small businesses over ordinary copper telephone lines already installed in hundreds of millions of homes and businesses worldwide. With DSL, consumers and businesses take advantage of having a dedicated, always-on connection to the Internet.
What is a Cable Modem (CM)?
- Cable modems are designed to operate over cable TV lines to provide high-speed access to the Web or corporate Intranets. A power splitter and a new cable are usually required. The splitter divides the signal for the "old" installations and the new segment that connects the cable modem. No television sets are accepted on the new string that goes to the cable modem.
What is the Difference between DSL vs. Cable Modem?
- Cable modem services offer shared bandwidth between your and your neighbors. Your speed will vary with how many people are on the cable modem network, which may be a disadvantage. With DSL service, you have a dedicated connection to your home.
How Does DSL Work?
- Traditional phone service connects your home or business to a telephone company office over copper wires that are wrapped around each other. The wires are called twisted pair. The digital modem, which may be purchased or rented, -- located at your location -- accesses the local telephone companies’ central office where a Digital Subscriber Line Access Multiplexer, which translates your DSL signal, has been installed. The signal is then transmitted from the copper telephone line onto a network backbone, and directed to the ISP’s location, where the ISP verifies the access to the network and delivers users to the Internet through the ISP’s relationship with a backbone network provider.
How Does the Cable Modem Work?
- The transmitted signal from the cable modem, which can be either purchased or rented, can be so strong that any TV sets connected on the same string might be disturbed. The isolation of the splitter may not be sufficient, so an extra high-pass filter can be needed in the string that goes to the TV-sets. The high-pass filter allows only the TV-channel frequencies to pass, and blocks the upstream frequency band. The other reason for the filter is to block ingress in the low upstream frequency range from the in-house wiring
What Types of DSL are Available?
- There are currently at least six different types of DSL. They are Asymmetric Digital Subscriber Line (ADSL), Symmetric Digital Subscriber Line (SDSL), ISDN Digital Subscriber Line (IDSL), High-bit-rate Digital Subscriber Line (HDSL), Very high-bit-rate Digital Subscriber Line (VDSL), and Rate-Adaptive Digital Subscriber Line (RADSL). Each one has different technical ranges, capabilities, and limitations.
What Types of Cable Modems are Available?
- There are three types of CM: external modem, internal modem, and interactive set-top cable box. A number of different cable modem configurations are possible. Over time more systems will arrive.
How Can I Get Digital Subscriber Line or Cable Modem (CM) Service?
- You should contact a provider in your geographical area. This entity may be your local telephone service provider (for DSL) or one of their competitors, or your local cable company (for CM). You can also find out whether DSL is available in your area by typing various keywords for Digital Subscriber Line (DSL) in an Internet search engine.
Can I Use the Same Equipment Everywhere?
- No. Because there are different DSL and CM systems available, equipment for one provider may not be operable in another area or with another provider. You should check with your current and/or prospected provider for technical compatibility and capability.
What are the Advantages to having DSL or CM?
- Faster
: DSL and cable modems are much faster than analog modems. Different varieties of DSL provide different maximum speeds, from twice as fast to approximately 125 times faster.- Always on
: Your DSL or CM connection is always there. There’s no need to dial up and listen to your modem squawk. And there’s no frustration about the line dropping.- Flat Rate Service
: DSL and CM typically don’t have usage-sensitive pricing, which means that the connection can be used any time for as long as you need without incurring usage charges. Technical advances enable prices to fall and gain in power, facilitating the creation and operation of global networks.What are the Disadvantages to having DSL or CM?
- Distance
: Distance between the user’s premises and phone company’s central office or cable installation is a primary factor deciding who can get these services and the speed of these services.- Limited Competition:
External providers must coordinate with local phone or cable companies to provide service, which may cause installation delays.- Security:
Because DSL and CM are always on, you may want to check with the provider about security vulnerability and precautions.- Technical Incompatibility:
DSL and CM equipment contain proprietary implementations, regardless if it is the same form of DSL or CM.How to Ensure You’re Satisfied with Your DSL or CM service?
- Prior to getting DSL, check with the provider to find out the "confirmed information rate," which is the minimum rate the provider guarantees to deliver data. You should contact the DSL or CM provider and make them aware of any adverse experience(s) you encounter after receiving the service. Many providers are interested in your experiences especially since the service is fairly new. You may also acquire service through a different provider in the event you are not pleased with your current service or service provider.
For general information on other telecommunication-related issues, you may contact the FCC’s Consumer & Governmental Affairs Bureau in the following ways:
Via the Internet at www.fcc.gov/cgb
Consumer Center, Voice: 1-888-CALL-FCC and TTY: 1-888-TELL-FCC
Address: Federal Communications Commission, Consumer & Governmental Affairs Bureau, 445 12th Street, SW, Washington, D.C. 20554
| last reviewed/updated on 02/12/02 |
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