英译汉。LANs consist of carefully selected groups of components (hardware and software).
英译汉。7 Most wide area networks, such as the PSTN, use a mesh (sometimes referred to as a network)topology.
英译汉。8 Twisted pair, coaxial cable and optical fibre are the three main types of transmission medium used for LANs.
英译汉。9 The Internet is used by millions of people across the world to communicate business and personal information.