TR-4AU is designed to transmit 4 audio signals via twisted pair cableIn the audio path, galvanic separation takes place and the impedance of the 600Ω signal is matched to the impedance of the symmetrical cable, which allows the transmission of the audio signal up to 1200 metersTransferring the audio signal via twisted pair has the advantage over the shielded cable that any interference is eliminated, because the signal is transmitted differentially
Two such devices are required to build a full signal transmission path