Communication equipments

The telephone is among the most widely used communication equipment in the world. The telephone system has been greatly enhanced and become a widely accepted communication apparatus in households and offices since its invention. The examples include the telephone answering system found in households, the voice mail system used in office environments. A significant contribution to the growth of telecommunications industry has been the high demand for radio communication services, such as cordless telephone service. Cordless telephones provide greater flexibility than traditional landline phones by permitting a user to move freely and not be physically restricted by a telephone cord. Wireless networks are an increasingly popular means of personal communications. People are using mobile terminals such as cellular telephones and fixed wireless terminals so that they can readily stay in touch with others. Cellular mobile telephony provides voice and data links between users of mobile devices and fixed devices on a network. It gives users mobility without regard to how they are actually connected to the network. Telecommunications networks are shifting from a circuit-switched architecture to a packet-switched architecture. The packet-switched networks allow dynamic bandwidth, and can be connectionless networks with no dedicated circuit or connection-oriented networks with virtual circuits having dedicated bandwidth along a predetermined path.