Internet Definitions and Telecom Industry Terms

Written by: Internet - Oct 6, 2008

Common DSL Terms and Definitions

Access Method - A technology used to access the Internet (dial-up, ISDN, cable modem or DSL).

ADSL - Asymmetric Digital Subscriber Line. Usually meant for home usage, this DSL service has a faster download speed and a slower upload speed. Download speeds may range from 256 Kbps to 7 Mbps.

Broadband - Digital technologies that offer consumers a single way to access voice, high-speed data services, video services, and interactive information delivery services.

Bandwidth - How much information you can send through a connection. Usually measured in bits-per-second (bps), kilobytes-per-second (Kbps), or megabytes-per-second (Mbps). A full page of English text is about 16,000 bits. A fast modem can move about 15,000 bits in one second.

CLEC - A CLEC (Competitive Local Exchange Carrier) is a telephone company that competes with an Incumbent Local Exchange Carrier (ILEC) such as a Regional Bell Operating Company (RBOC), GTE, ALLNET, etc. With the passage of the Telecommunications Act of 1996, there has been an explosion in the number of CLECs. The Act allows companies with CLEC status to use ILEC infrastructure.

Cable Modem - A cable modem is a device that enables you to hook up your PC to a local cable TV line and receive data at about 1.5 Mbps. A cable modem can be added to or integrated with a set-top box that provides your TV set with channels for Internet access.

Central Office - Belonging to your local phone provider, this is the building that houses the phone equipment for your area, such as switches. DSL lines run from the customer's home to this office. It is the distance from this office that determines whether or not you can get DSL service in your home, and what speeds you qualify for. Usually, if you are within about 18,000 feet from the central office, you are able to get some form of DSL service.

Dedicated Line - A communications circuit or channel for the exclusive use of a particular subscriber. For example, dedicated lines are used for computers when large amounts of data need to be moved between two points.

DirecPC - Internet access that uses a satellite dish to receive data users request over the Internet. Outbound information (such as a URL request) is requested in the traditional way, usually via a dial-up connection.

DSL - A method for moving data over regular phone lines. A DSL circuit is much faster than a regular phone connection, and the wires coming into the subscriber's premises are the same (copper) wires used for regular phone service. A DSL circuit must be configured to connect two specific locations, similar to a leased line. However, DSL uses previously unused frequencies of the line so that a user may connect to the Internet and talk on the phone at the same time.

Ethernet - A very common method of networking computers in a LAN. Ethernet will handle about 10,000,000 bits-per-second and can be used with almost any kind of computer.

Fire Wall - A combination of hardware and software that separates a LAN into two or more parts for security purposes. Often used to separate an in-house LAN from the Internet.

G. Lite - A DSL service that offers a download speed that is slower than other forms (maximum of 1.5 Mbps). But, it is an ITU (International Telecommunications Union) standard, which means that DSL may soon be available from many vendors and may operate interchangeably. This may eliminate the need for multiple installation visits from providers.

HDSL - High bit-rate Digital Subscriber Line that delivers T1 speeds. This requires two lines at present.

IDSL - DSL transferred at 128Kbps on regular copper lines. This uses ISDN transmission coding, but no form of dial-up.

IP Address - Every machine that is on the Internet has a unique IP number - if a machine does not have an IP number, it is not really on the Internet. Most machines also have one or more Domain Names that are easier for people to remember.

ISP - Internet service provider. Where you get your Internet service.

LAN - A LAN (Local Area Network) is a computer network that spans a relatively small area. Most LANs are confined to a single building, connecting two or more computers. Each individual computer in a LAN has its own CPU with which it executes programs, but it is also able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as communicate with each other, by sending e-mail or engaging in chat sessions. LANs are capable of transmitting data at very fast rates, much faster than data can be transmitted over a telephone line. Because the distances are limited, there is a limit on the number of computers that can be attached to a single LAN.

Modem - Modulator-demodulator. A device that converts digital signals into analog signals and enables computers to receive data over telephone networks.

NIC Card - Network Interface Card. It plugs into a computer and adapts the network interface to the appropriate standard. ISA, PCI and PCMCIA cards are all examples of NICs.

PPP - Most well known as a protocol that allows a computer to use a regular telephone line and a modem to make TCP/IP connections and thus be truly on the Internet.

RADSL - Rate Adaptive Digital Subscriber Line. A version of ADSL where modems test the line at start-up and adapt their operating speed to the capacity of the line.

Router - This is your connection between networks for DSL service. It keeps packets flowing from everywhere, directing traffic according to programmed routing tables.

SDSL - Single Line DSL. Requires just one twisted line compared to other forms of DSL that might need two or three. It is also symmetric, which means that the maximum upstream and downstream speeds are the same.

SMTP - Simple Mail Transfer Protocol. The main protocol used to send electronic mail on the Internet.

TCP/IP - Transmission Control Protocol/Internet Protocol. The suite of communications rules and encoding specifications for sending data used to connect hosts on the Internet. The protocol defines a common set of rules and signals that computers on the network use to communicate.

T-1 - A leased-line connection capable of carrying data at 1,544,000 bits-per-second.

T-3 - A leased-line connection capable of carrying data at 44,736,000 bits-per-second.

Truck Roll - The term used for the necessary visit to the customer for installation