Optical (Toslink) connection

Toslink (Toshiba Link) is an optical digital audio connection. Uses a fiber-optic cable terminated with a square plastic connector to transmit S/PDIF digital audio as pulses of light.

Advantages

• Complete galvanic isolation – no ground loop possible
• Immune to electrical interference
• Cheap cables – $5 optical cable is fine for typical runs

Limitations

• Maximum ~96 kHz PCM (some modern implementations do 192 kHz)
• Cable length limited to ~15 feet reliably
• Fiber can crack if bent sharply

Use cases

Best for connecting TV to amp (bypasses AV receiver ground loops), CD player to DAC, older streamers. The AIYIMA A80, Fosi Audio S3, and most amps have optical inputs.