Affordable budget optical SPDIF connection cable for digital audio transmission for sound cards, CD/DVD drives, DVD stand-alone devices, hi-fi systems etc. Optical connection cable for digital audio transmission. Optical connection cable for digital audio transmission. For example, for sound cards, CD/DVD drives, DVD stand-alone devices, hi-fi systems etc. This signal transmission is often referred to as optical SPDIF, not to be confused with electrical SPDIF via RCA/cinch coaxial cable.