A data communications network that serves users across a broad geographic area and often uses transmission devices provided by common carriers.
A large and diverse network connecting most major points in a company or other organization. Differs from a WAN in that it is privately owned and operated.
The sending and receiving of data between two endpoints.
A result-oriented unit of communication processing.
Voice over IP (VoIP)
The capability to carry normal telephony-style voice over an IP-based internet with POTS-like functionality.
A transmission system that multiplexes multiple independent signals onto the cable.
An employee who enjoys some flexibility in working location and hours. The daily commute to an office is replaced by telecommunication links.
A specially designed room used to wire a data or voice network.
The part of a network that acts as the primary path for traffic that is most often sourced from and destination for other networks.
Metropolitan-area Network (MAN)
A network that spans a metropolitan area.
An industry-standard switched data link layer protocol that handles multiple virtual circuits using HDLC encapsulation between connected devices.
Asynchronous Transfer Mode (ATM)
An international standard for cell relay in which multiple service types (such as voice, video, or data) are conveyed in the fixed-length (53-byte) cells.
High-Level Data Link Control (HDLC)
A bit-oriented synchronous data link layer protocol developed by ISO.
Customer Premises Equipment (CPE)
Terminating equipment, such as terminals, telephones, and modems, supplied by the telephone company, installed at customer sites, and connected to the telephone company network.
A communication path.
In IBM, the specific path between large computers (such as mainframes) and attached peripheral devices.
Data Communications Equipment (DCE)
The devices and connections of a communications network that comprise the network end of the user-to-network interface.
Data Terminal Equipment (DTE)
A device at the user end of a user-network interface that serves as a data source, destination, or both.
A line from the premise of a telephone subscriber to the telephone company CO.
A transmission medium of copper wire or optical fiber wrapped in a protective cover.
A communications line that is indefinitely reserved for transmissions, rather than switched as transmission in required.
Central Office (CO)
A local telephone company office to which all local loops in a given area connect and in which circuit switching of subscriber lines occurs.
A device that converts digital and analog signals.
A digital WAN carrier facility.
Transmits DS1 formatted data at 1.544 Mbps through the telephone switching network, using AMI or B8ZS coding.
A digital WAN carrier facility.
Transmits DS3 formatted data at 44.736 Mbps through the telephone switching network
Channel Service Unit (CSU)
A digital interface device that connects end-user equipment to the local digital telephone loop.
Data Service Unit (DSU)
A device used in digital transmission that adapts the physical interface on a DTE device to a transmission facility such as T! or E1.
A TDM transmission method that usually refers to a line or cable carrying a DS-1 signal.
A communications processor that connects asynchronous device to a LAN or WAN through network and terminal emulation software.
An ITU-T standard that defines how connections between DTE and DCE are maintained for remote terminal access and computer communications in packet data networks (PDN).
Public Switched Telephone Network (PSTN)
A general term referring to the variety of telephone networks and services in place worldwide.
Plain old telephone service (POTS)
Integrated Services Digital Network (ISDN)
A communication protocol, offered by telephone companies, that permits telephone networks to carry data, voice, and other source traffic.
Point of Presence (POP)
A point of interconnection between the communications facilities provided by the telephone company and the building's main distribution facility.
In a packet-switched star topology, a router that is part of the backbone and that serves as the single pipe through which all traffic from peripheral networks must pass on its way to other peripheral networks.
High-Speed Serial Interface (HSSI)
A network standard for high-speed (up to 52 Mbps) serial connections over WAN links.
Point-to-point Protocol (PPP)
A successor to SLIP.
Provides router-to-router and host-to-network connections over synchronous and asynchronous circuits.
A communications path between two or more points.
Time-Division Multiplexing (TDM)
A technique in which information from multiple channels can be allocated bandwidth on a single wire based on preassigned time slots.
A switching system in which a dedicated physical circuit path must exist between sending and receiver for the duration of the "call."
A networking method in which modes share bandwidth with each other by sending packets.
Uses packet-switching technology to transfer data.
A term used to describe data transfer without the existence of a virtual circuit.
A term used to describe data transfer that requires that establishment of a virtual circuit.
Data Link Connection Identifiers (DLCI)
A value that specifies a PVC or SVC in a Frame Relay network.
Virtual Circuit (VC)
A logical circuit created to ensure reliable communication between two network devices.
Permanent Virtual Circuits (PVC)
A virtual circuit that is permanently established.
Switched Virtual Circuits (SVC)
A virtual circuit that is dynamically established on demand and that is torn down when transmission in complete.
A transmission line reserved by a communications carrier for a customer's private use.
The science of converting sound to electrical signals and transmitting it between widely removed points.
Bearer (B) Channels
In ISDN, a full-duplex 64-kbps channel used to send user data.
The process of sending a transmission signal over a physical medium or purposes of communication.
Delta (D) Channel
A full-duplex 16-Kbps (BRI) or 64-kbps (PRI) ISDN channel.
Basic Rate Interface (BRI)
An ISDN interface composed of two B channels and one D channel for circuit-switched communication of voice, video, and data.
Primary Rate Interface (PRI)
An ISDN interface to primary rate access.
The establishment of common timing between sender and receiver.
A wide-area digital transmission scheme used predominantly in Europe tat carries data at a rate of 2.048 Mbps.
A wide-area digital transmission scheme used predominantly in Japan that carries data at a rate of 1.544 Mbps.
Call Setup Time
A time required to establish a switched call between DTE devices.
A cable consisting of a hollow cylindrical conductor that surrounds a single inner wire conductor.
A communication system in which multiple channels of programming are transmitted to homes using broadband coaxial cable.
The endpoint of a broadband network.
Electromagnetic waves in the range 1 to 30 GHz.
A router or access server designated as a buffer between any connected public network and a private network.
Serve as a central junction point for the wiring and wiring equipment that is used to interconnect network devices.
Metropolitan-area Network (MAN)
A network that generally spans a larger geographic area than a LAN but a smaller geographic area than a WAN.