In telecommunications, a toll switching trunk or toll connecting trunk<ref>The Digital Future, 1979 Toll connecting trunk</ref> is a trunk connecting an end office 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.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>