Multiswitch hooked up backwards, it is important?

[geoffhazel]

I have DirectTV with 2 3x4 multiswitches, each fed by a 1x2 splitter from the cables off the dish. They feed 3 two cable tivo units and one plain receiver. Well today two tivos off one MS started having fits about their signal strength, but the other tivo was fine on all transponders, so I figured the issue was somewhere with one multiswitch that was feeding the other two tivos.
And while fiddling with things, I put my multimeter on the outputs from the 1x2 splitters, and found 18v on one cable, 13v on the other one. That matched up very nicely to the 18v and 13v labels on the inputs of the multiswitch. But when I went to connect a replacment multiswitch, I found that the 18v and 13v had been connected to the opposite inputs, and HAD BEEN that way for months. And yet somehow it worked most of the time. But it wasn't working now. when I matched the input voltage to the labels, it all worked flawlessly.
So what I'm wondering is, how did it work in the first place? How important is it to get the cables put on the "right" inputs?

[JimSpence]

With your setup using splitters to feed two multiswitches it is very important. The outputs of the splitters must connect to the same inputs on the switch. In other words, one splitter feeds the 13v inputs and the other feeds the 18v inputs. It is also recommended that the splitter only pass DC on one leg. Are you sure that everything worked okay before? No anomalies?

[geoffhazel]

Yeah, it seemed to work pretty well, in fact. We would occasionally get a channel act like it wasn't getting a very clear signal and get all blocky and such, but not very often. Then the other day, we just lost signal. I have two multiswitches, and since I had one good tivo with two clear signals on most transponders, I figured I was good from antenna down to the splitters and that one multiswitch had gone bad. I swapped switches with a new one and it didn't help; that's when I realized the inputs on one were swapped. So I had one bad m-s, and one wired incorrectly. Since putting in a new m-s and wiring them the same, everything is fine. But one of them had been wired wrong for at least a year.

[sxrxrnr]

For several years I ran 8 receivers off a single dish by daisy chaining three 2 into 4 switches. However if I did not have them hooked up exactly correct, I would often have "searching for sat" messages. I never did figure out why as all the switch makers said it should not make any difference. One thing I did learn early on, was that they must be able to pass the 22HZ single or HD channels would not work, also some other oddities like channel 384(NASA) would not come in. I assume had something to do with sat 119 and commands being given to the lnb to look at this sat for HD and some other odd channels. Been running a 4 into 8 for sometime now and also am running another dish(D* 5 lnb) so all is ok and simpler now.