Digital audio standard, the European Broadcast Union proposes this format to the Audio Engineering Society and approves it in 1986, called the AES / EBU standard. It allows to transfer digital audio with a sample rate of 32, 44´1 or 48 kHz and a quantization of 16 or 20 bits. Two audio channels are transferred along a line, to achieve this, the channels are multiplexed by time division, so that four audio channels can be worked through two XLR-type connectors similar to those used for analog audio. The connectors must have greater impedance since the digital audio has greater bandwidth.