also why cant you recieve a signal from both the output and input?
You're kidding, right? I think that's what those rolling eyes are for.
can you explain your diagrams a little more because i thought the oade cable just split the incoming signal. would like to know how they actually work.
The Oade cable definitely does not just split the incoming signal.
[1] In order to pass a digital signal out of the Oade cables, the deck into which the 7-pin is plugged MUST be on and recording. If it is off or not recording, then no signal is passed out of the 7-pin. This is because the signal goes in the coax, through the 7-pin into the deck, then back out the 7-pin to the coax out.
[2] If the Oade cable just split the incoming signal, you'd be able to run signal in through the coax and out through the other coax without the 7-pin even plugged in (or the 7-pin plugged into a deck that isn't recording). However, that isn't how it works. This is why, when the lead deck's batteries die, the following decks in the chain get hosed as well. If the Oade cable simply split the signal, the downstream decks would be fine. Try it sometime when you have a couple decks available - it's easy to test that it doesn't simply split the signal.
The diagrams are just a way of expressing shorthand the signal paths [1,2] I described above (sorry, I screwed up my diagrams before...no wonder they were confusing!):
[1]
coax input > 7-pin into deck > 7-pin out of deck > coax output[2]
/ 7-pin into deck
coax input
\ coax output