Public switched telephone network (PSTN)
Public Switched telephone network (PSTN) is the global collection of interconnects originally designed to support circuit-switched voice communication. The PSTN provides traditional Plain Old Telephone Service (POTS), also known as "landline phone" service, to residences and many other establishmenADD MORE INFORMATION OF PSTN
ts. Parts of the PSTN are also utilized for DSL, VoIP and other Internet-based network technologies. One PSTN link supports 64 kilobits per second (Kbps) of bandwidth for data. In residences, the PSTN phone line typically carries this bandwidth over a copper cable. Traditional dial-up network modems utilize nearly 56 Kbps of this bandwidth when connected to a phone line.
Local area networks (LANs)
A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. A LAN is useful for sharing resources like files, printers, games or other applications. A LAN in turn often connects to other LANs, and to the Internet or other WAN. Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist.
Metropolitan area networks (MANs) A Metropolitan Area Network (MAN) is one of a number of types of networks (see also LAN and WAN). A MAN is a relatively new class of network, it serves a role similar to an ISP, but for corporate users with large LANs. There are three important features which discriminate MANs from LANs