Nothing fancy, just a cable with a regular RCA jack (the one used for pretty much all audio/video cabling) at each end. Every cable you have except speaker wire is probably an "RCA patch cable"...

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8