There's no code, but there's standard practices. Do a search on the net and you can see the best way to install low voltage/current wiring.
The main thing to keep in mind is routing of the cable/wire. Stay away from anything that can cause or induce noise/current in the wire. Like others said, stay away from metal ducting. As well, try not to run the cables along side power wires. If running along the inside of a joist, put them up on the side opposite the power. Try not to route through the same holes as well. Now, if drilling new holes, there are limitations of where you can drill and how big. That should be available in the regular code.
edit: I should read better today so I don't post the same info
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