56K Line - A digital phone-line connection (leased line) capable of carrying 56,000 bits per second. At this speed, a megabyte will take about 3 minutes to transfer. The standard modem in use today is the 56 Kbps dialup modem.

ADSL (Asymmetric DSL) - ADSL offers differing upload and download speeds and can be configured to deliver up to 6 Mbps from the network to the customer ­ that is up to 120 times faster than dialup service and 100 times faster than ISDN. ADSL enables both voice and high speed data to be sent simultaneously over existing phone lines. This type of DSL is the most predominant in commercial use for business and residential customers around the world. ADSL is good for general Internet access and for applications where downstream speed is most important, such as video-on-demand.

Bandwidth - The data transfer capacity of an electronic communications system. When a measurement of bandwidth is given, it primarily represents the maximum data transfer rate of such a system measured in kilobits per second (Kbps) or megabits per second (Mbps).

Baud - Baud was the prevalent measure for data transmission speed until replaced by a more accurate term, bits per second (bits per second).

Bit - A bit is the smallest unit of data in a computer. A bit has a single binary value, either 0 or 1. In most computer systems, there are eight bits in a byte.

BPS (Bits Per Second) - In data communications, bits per second (abbreviated bps) is a common measure of data speed for computer modem and transmission carriers. As the term implies, the speed in bps is equal to the number of bits transmitted or received each second.

Byte - In most computer systems, a byte is a unit of data that is eight binary digits long. A byte is the unit most computers use to represent a character such as a letter, number, or typographic symbol (for example, "g", "5", or "?").

DSL (Digital Subscriber Line) - A technology that exploits unused frequencies on copper telephone lines to transmit traffic much higher speeds. DSL can allow voice and high speed data to be sent simultaneously over the same line. Because the service is 'always available,' end-users don't need to dial in or log on to the Internet.

Ethernet - Ethernet is the most widely-installed local area network (LAN) technology. The most commonly installed Ethernet systems are called 10BASE-T and provide transmission speeds up to 10 Mbps.

Fire Wall - A combination of hardware and software that separates a LAN into two or more parts for security purposes.

HDSL (High Data Rate DSL) - Available at 1.5 or 2.3 Mbps, HDSL does not provide standard telephone service over the same line. It is seen as an economical replacement for a T-1 line.

IDSL (Integrated Services Digital Network DSL) - Also called ISDN DSL. This is a form of DSL that supports symmetric data rates of up to 144 Kbps using existing phone lines. IDSL differs from its relative, ISDN, in that it is an "always-available" service, but capable of using the same terminal adapter, or modem, used for ISDN. Unlike true ISDN, it's only for data. It can reach farther distances than ADSL or SDSL.

IP Address - A unique number consisting of four parts separated by dots. For example: 123.45.678.9. 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.

ISDN - Integrated Services Digital Network. Basically a way to move more data over existing regular phone lines. ISDN is rapidly becoming available to much of the USA and in most markets it is priced very comparably to standard analog phone circuits. It can provide speeds of roughly 128,000 bits per second over regular phone lines. In practice, most people will be limited to 56,000 or 64,000 bits per second.

Kilobit - Approximately one thousand bits (1024 bits, to be exact). Data transfer rates are measured in kilobits per second, abbreviated as Kbps.

Kilobyte - Approximately one thousand bytes (1024 bytes, to be exact). While kilobits are used to measure data transfer, kilobytes are used to measure memory capacity. Kilobyte is usually abbreviated as K or KB. For example, 256K of RAM means a computer has 256,000 bytes of Random Access Memory.

LAN (Local Area Network) - A computer network limited to the immediate area, usually the same building or floor of a building.

Leased-Line - Refers to a phone line that is rented for exclusive 24-hour, 7-days-a-week use from your location to another location. Many of the highest speed data connections will require a leased line, such as T-1's and T-3's.

Megabit - Approximately one million bits. Higher rates of data transfer are measured using megabits per second, abbreviated as Mbps.

Megabyte - Approximately one million bytes. While megabits are used to measure data transfer, megabytes are used to measure memory capacity. Megabyte is usually abbreviated as M or MB. For example, 200 MB of disk storage space on a web hosting account means the account has 200,000,000 bytes of hard drive space upon which to store its files.

Modem - The term is taken from the first letters of "Modulator, Demodulator". A modem is a device that you connect to your computer and to a phone line that allows the computer to talk to other computers through the phone system. Modems convert the digital signal to analog so it can travel the phone line and then back to digital again for processing.

NIC (Network Interface Card) - A NIC is a computer circuit board or card that is installed in a computer so that it can be connected to a network. Personal computers and workstations on a local area network (LAN) typically contain a network interface card specifically designed for the LAN transmission technology, such as Ethernet or token ring. Network interface cards provide a dedicated, full-time connection to a network. Most home and portable computers connect to the Internet through as-needed dial-up connection. The modem provides the connection interface to the Internet service provider.

PPP (Point to Point Protocol) - A protocol that allows a computer to use a regular phone line and a modem to make TCP/IP connection and thus be really and truly on the Internet.

RADSL (Rate Adaptive DSL) - A non-standard version of ADSL that adjusts dynamically to varying lengths and quality of access lines. With RADSL, the modem will test the line at start up and adjust its operating speed to the fastest the line can handle.

SDSL (Symmetric DSL) - SDSL is a vendor-proprietary version of DSL that can provide the customer with speeds ranging from 128 Kbps to 2.32 Mbps. SDSL offers the same upstream and downstream speeds, but it can't share the line with voice communications.

T-1 Line - A leased-line connection capable of carrying data at 1,544,000 bits per second, or 1.544 Mbps. Generally, a T-1 line will move a megabyte of data in under 10 seconds. That is still not fast enough for full-screen, full-motion video, for which you need at least 10,000,000 bits per second. T-1 is the fastest speed commonly used to connect networks to the Internet.

T-3 Line - A leased-line connection capable of carrying data at 45,000,000 bits per second, or 45 Mbps. This is more than enough to do full-screen, full-motion video.

TCP/IP - Stands for "Transmission Control Protocol / Internet Protocol" - TCP/IP is a suite of communications protocols that forms the basis for and defines the Internet.

UADSL (Universal Asymmetric DSL) - UADSL can deliver up to 1.5 Mbps downstream and 512 Kbps upstream. Like ADSL, it's asymmetric and allows you to use the same telephone line for both standard telephone service as well as high speed Internet connectivity. With the speeds that UADSL provides, it is intended primarily for consumers rather than businesses.

URL (Uniform Resource Locator) - The standard way to give the address of any resource on the Internet that is part of the World Wide Web (WWW). A URL looks like this:

The most common way to use a URL is to enter into a WWW browser program such as the Microsoft Internet Explorer or Netscape.

VDSL (Very High Bit Rate DSL) - A new type of DSL that is still in development, VDSL can transmit in speeds up to 26 Mbps, over distances up to 50 Meters on short loops such as from fiber to the curb. The highest speeds are currently obtainable at short distance only.

WAN (Wide Area Network) - A term referring to any Internet or network that covers an area larger than a single building or campus.