There is a resistor.
"A 75 Ohm resistor within an RCA phono plug for the termination of the unused digital output or input can avoid this problem. The result is a more accurate, cleaner and well-balanced sound."
"A 75 Ohm resistor within an RCA phono plug for the termination of the unused digital output or input can avoid this problem. The result is a more accurate, cleaner and well-balanced sound."