Abstract: A tone relay system comprises a tone detector arranged to receive a sequence of signal samples and to provide a plurality of media descriptors, each media descriptor comprising a cell of one or more of the signal samples and a tone detection meta-information for the cell; and a tone relay module arranged to receive each media descriptor, to perform an evaluation of the meta-information and modify the meta-information depending on one or more preceding media descriptors when a result of the evaluation indicates an undetermined tone state, and to provide the media descriptors with a predetermined delay to a tone aggregator module, when the meta-information indicates a tone, for transmission over a network, and to provide the media descriptors without the predetermined time delay to an encoder module, for transmission over the network, otherwise.