Bit -- The most basic unit of measuring information flow. Any voice, data, or video information can be turned into a stream of bits. Narrowband telecommunications moves thousands of bits (kilobits) per second, which is considered slow, but good enough for voice calls.

Broadband -- is one million bits (megabits) per second or faster. A gigabit network moves billions of bits per second.

Digital telecommunications -- an information transmission, storage and processing method that uses electronic or optical pulses, also called bits. Digital switching technology transmits and processes calls faster and better than its electromechanical predecessors. This improves both the capacity and the efficiency of the network.

Exchange -- the local area served by a central office or switching center. An exchange can be identified by the area code and first three digits of a phone number. Exchanges are grouped to form a Local Access and Transport Area.

Fiber ring -- a fiber-optic cable arrangement that sends every customer's data in two opposite directions toward another destination connected to the ring. This redundancy guarantees that an accidental cut in the ring will not stop the customer's data from reaching its destination.

ISDN (Integrated Services Digital Network) -- a digitally switched network that provides very fast, simultaneous transmission of voice, data and images over a single telephone line.

LATA (Local Access and Transport Area) -- Any of 161 local telephone serving areas in the United States. When the local and long-distance phone businesses were split up in 1984, LATAs were established to create boundaries that distinguish between local and long-distance service. Calls between LATAs are switched by long-distance companies.

Microwave -- a way of providing telecommunications bandwidth via a series of antennas, transmitters and reflectors on towers. Voice, data, or video communications travel in a straight line from tower to tower. Microwave can be made fully compatible with digital service.

POP (Point of Presence) -- the site where an interexchange carrier's equipment connects to a local exchange carrier's network.

Redundancy -- backup equipment cabling in a network designed to take over instantaneously and keep information flowing in case the main equipment or cable route fails.

SONET (Synchronous Optical Network) -- a technical standard for transmission of light signals over optical fiber. SONET allows different fiber systems or networks to interconnect efficiently with a high level of accuracy and customer control.

Switched 56 service -- a data communications service that transmits digital information at 56,000 bits per second using ordinary copper cable. Current technology allows video to be transmitted over telephone lines employing Switched 56 service.

Telecommunications infrastructure -- the cables, switches, radio towers, and other facilities and equipment that are required to make telecommunications work. Cables and wires that connect customers to switching centers are called outside plant. Equipment under the roof is inside plant.

T-Carrier services -- a family of high-capacity digital telecommunications services requiring leased private lines. The most common T-carrier is called T-1, or DS1. It provides 24 separate channels of high quality voice connections, or can be set up as 1.5 megabits per second of data communications bandwidth. T-3 (DS-3) is a leased line service with approximately 30 times the bandwidth of T-1. Fractional T-1 is a service that enable businesses to lease incremental bandwidth, generally in increments of 128 kilobits per second, on a T-1.

WATS (Wide Area Telecommunications Service) -- a fixed-rate long-distance calling service offered by local and long-distance phone companies. WATS service allows calls to be made and received without users being charged for each call. Toll free numbers are one type of WATS.