1) My technical dictionary says signal path, which is confirmed by a large number of Google hits, e.g.:

When you push in the "EQ to SC" switch, the two mid-band sections get routed to the sidechain input of the compressor. The Treble and Bass sections remain equalizers in the final signal path and retain the ability to switch them in/out and pre/post.
www.barryrudolph.com/mix/avalon.html

2) However, not being a sound studio expert, I suppose, you might also need signalling route, which Eurodicautom defines as "a predetermined path to be taken by signal messages sent from a specified node to another specified node,but which may be dependent on the condition of the signalling network at the time of use"

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As also appears from the first example, the difference would be that "signal path" is the more concrete term and would refer to cables etc.

With so little context it is difficult to decide which term - "signal path" or "signalling route" - you need, but I hope this helps.