Wide Area Network (WAN) is the term employed to describe networks that connect Local Area Networks (LANs) or stand-alone systems via remote links, e.g. ISDN, X.25. Probably, the most extensive and familiar WAN is the analogue public telephone network, in which dial-up connections are established to provide mainly voice communication links. The use of this network as a platform for data transmissions via modem or facsimile will continue to be significant.