Output triggers

I’m a new SG preamp owner and first time poster. I have the preamp for a few weeks now and really like it, its a keeper. So much that i am very tempted to get the SG dac when i can get a good deal.

Anyway I am just curious about the 12v triggers on these units, why do they have two outs and no ins.
What if i want to turn them on from another component? One out and one in would be better.