I just got one of these and interfaced it with my existing Xantech system without any issues at all. I took the IR output from the Harmony Hub, cut up an existing audio cable I had with that connector, attached the ground (shielding) to the ground input and the other wire to the IR in. I didn't test the wires, but I would assume the tip was the IR in and the ground was the ring. If it's wrong, it shouldn't be doing any long term damage - it just won't work at all. Reverse them and you'll be fine.