I second Onhwy61.
The same applies for RCA terminated digital interconnects. They have to be 75 Ohms.
Thus any digital RCA interconnect may be used for analog duty, but not the other way around. Well, one could use an analog interconnect for digital duty, it will "work", but the sound quality will suffer from reflection-induced jitter if the cable is not 75 Ohms.
In the XLR world the same applies, only the required characteristic impedance is different.
The same applies for RCA terminated digital interconnects. They have to be 75 Ohms.
Thus any digital RCA interconnect may be used for analog duty, but not the other way around. Well, one could use an analog interconnect for digital duty, it will "work", but the sound quality will suffer from reflection-induced jitter if the cable is not 75 Ohms.
In the XLR world the same applies, only the required characteristic impedance is different.