Short for Sony and Phillips Digital Interconnect Format, the S/PDIF or SPDIF interface is used to transmit digital audio, in a compressed form, between audio equipment and home theater systems. The S/PDIF interface can utilize a coaxial cable or a fiber optic cable to transmit the audio. Common equipment to use this interface are DVD Players and CD Players, connecting to a home theater system for Dolby Digital or DTS surround sound. High quality sound cards and laptops will also have this connector. In the first picture to the right, is an example of what the SPDIF connector may look like on your computer motherboard.
The audio transmitted is through the S/PDIF interface is defined by the IEC 61937 standard. The common formats transmitted are the 48 kHz sample rate (used in DAT) and the 44.1 kHz sample rate (used in CD audio). In the picture to the second picture to the right, is an example of a fiber optic connection on the back of audio equipment.