Modem

A device for transmitting usually digital data over telephone wires by modulating the data into an audio signal to send it and demodulating an audio signal into data to receive it.

Local Area Conector

LANs are networks that connect devices, like computers and printers, over short distances typically within an office premises or campus.Communication devices are connected through cables within a distance of 2000 feet.

Intranet

An inhouse Web site on the company's local area network (LAN) that serves employees only, and almost every medium to large company has an intranet. Although intranet pages may have links to Web sites on the Internet, the intranet is not exposed to, or is accessed by, the general public.

Internet

An interconnected system of networks that connects computers around the world via the TCP/IP protocol

Hub

In an Ethernet network, a device to which all clients and servers are wired. Most Ethernet hubs are active hubs and regenerate the data bits on the output side in order to maintain a strong signal

Hacker

A person who uses a computer system without a specific, constructive purpose or without proper authorization.

Firewall

Any of a number of security schemes that prevent unauthorized users from gaining access to a computer network or that monitor transfers of information to and from the network.