I think the arrows are supposed to point in the direction that the signal will go like from the 990 to the 7125 and the sacd player to the 990 etc , thats how I have mine and it seems to work also ,you have to loosen the barrel ends a little bit and they go on easier hope I helped.
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Outlaw 990/7125,Denon 2910,Toshiba A3, Klipsch RF35,RC35,RS35,RW12,SMS-1