It's a dual channel thing, though, and the GT-10 seems to only have tip->sleeve switching on its switch relay output (it can only control one switching function). If you use a regular patch cable to connect the GT-10 switch output to this, loop 2 will be permanently on. That means you'd either have to connect a patch cable from send to return on loop 2 (to get the signal through), or use a TRS plug (with the ring connection left open) in the switch input jack. You could also use an insert cable and skip the plug that connects to the "ring".