Computer networks have been a boon for businesses because they connect different makes and models of microcomputers, minicomputers or even mainframe computers, allowing for shared communication, files and equipment. The first networks appeared in the 1960s when multi-user networks were introduced. In multi-user systems, dumb terminals, which do not have processing capabilities of their own, are connected to a central host computer, which shares processing time with these dumb terminals. Now much more popular are Local Area Networks, or LANS, which appeared in the early 1970s. A LAN is a communication network privately owned by the organization using it. LANs utilize stand-alone microcomputers rather than dumb terminals and can vary greatly in size, range and complexity. The actual distance and number of computers that can be connected is highly dependent upon the type of LAN and communication line used. Telephone lines are sometimes used and are...