Digital Audio


'Sony/Philips Digital Interface'

IEC958 (named IEC60958 at 1998) is the standard for AES/EBU and S-PDIF. S/PDIF is the consumer version of the AES/EBU-interface. The two formats differ only in the subcode information and the connector.

Signal transport: 75-ohm coax cable with cinch or BNC connector. By specification, the max. length is 25 feet. With good 75-ohm cable and good 75-ohm connectors it is possible to run much longer lines. It depends also on the quality of the transmitter, the receiver and the impedance match for the entire line.

Optical version: plastic fiber cable with Toslink connectors, max. cable length 10 meters.

Cable 75ohm  
Line Driver Zout: 75ohm +/-20% (100kHz .. 6Mhz)    Vout: 0.4Vpp .. 0.6Vpp 
Line Receiver Zin: 75ohm  Vin: 0.2Vpp .. 0.6Vpp
Connector RCA (or BNC)  
Signal Level 0.5..1V  
Modulation biphase-mark-code  
Subcode information SCMS copy protection info  
Max. Resolution 20 bits (24 bit optional)  

Comparison between AES/EBU and S/PDIF
Cabling 110 ohm shileded TP 75 ohm coaxial or fiber
Connector 3-pin XLR RCA (or BNC)
Signal level 2..7V 0.5..1V
Modulation biphase-mark-code biphase-mark-code
Subcode information ASCII ID text SCMS copy protection info
Max. Resolution 24 bits 20 bits (24 bit optional)

Digital audio (SPDI/F and AES/EBU) contain frame rate (timing speed) information in the audio bit stream but not frame number (timecode) information. Therefore timecode can not be 'withdrawn' out of the audio bit stream.

S/PDIF to Toslink Converter, MIDIman

Full S/PDIF Information by EPANORAMA.NET