High Quality Content by WIKIPEDIA articles! In telecommunication, a toll switching trunk is a trunk connecting one or more end offices to a toll center as the first stage of concentration for intertoll or long distance traffic. Operator assistance or participation may be an optional function. In U.S. common carrier telephony service, a toll center designated Class 4C is an office where assistance in completing incoming calls is provided in addition to other traffic; a toll center designated Class 4P is an office where operators handle only outbound calls, or where switching is performed without operator assistance.Telecommunication is the transmission of messages, over significant distances, for the purpose of communication. In earlier times, telecommunications involved the use of visual signals, such as smoke, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded drumbeats, lung-blown horns, or sent by loud whistles, for example.

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