AES3 is an industry-standard digital audio interface intended mainly for professional use. It transmits a serial data stream in balanced form over a screened twisted pair cable. The original idea came from a wish to re-use existing cabling in broadcast and recording studios, which typically contain miles of screened twisted pair cable already, used for balanced analogue signals. The data stream contains a stereo pair of up to 24-bit data, messages (to identify the data), status flags and synchronisation pulses (used to extract the word clock).
For reliable operation, the output stage impedance, the characteristic impedance of the cable and the load impedance at the receiver should all be 110 ohms. To avoid interference from other appliances, the screen wire must be securely connected to chassis at both ends. The interface is commonly used at sample rates up to 192kS/s.