Yeah, it really depends on what he patches out of...
1) if he patches out of something with an analog line-out (generally a 1/8" trs), then you'll need a 1/8">1/8" stereo TRS cable. This is the simplest you can get.
2) if patching out of RCA line-outs, you'll need a RCA>1/8" TRS Y Adapter cable. Again, pretty simple.
3) if you are patching optical digital, you'll need a toslink>toclink optical cable, and at least 1x 1/8" TRS Optical adapter plug.
4) if you are patching coax, you'll need a coax digi cable, a Hosa ODL276 and the optical cable mentioned above.
But again, this is very general, what you need will depend on the individual situation, there is no "the cable" like there is with the Sony DATs and the 7-pins...
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