There’s a lot of confusion about that single, red-labeled port on a DIRECTV splitter. A customer recently asked if that’s where your Genie DVR goes, and that sort of makes sense.
The red port is the power-passing port. DIRECTV equipment needs power to function and rather than plugging your dish or multiswitch into a wall outlet, that power is carried through the coaxial cable. This makes it a lot easier to place the dish or multiswitch since there doesn’t need to be an outlet nearby.
Somewhere in your DIRECTV SWM system you may have a grey or black box that looks something like this:
This is the power inserter. It’s only job in life is to put power onto the coaxial cable. However, since that power could fry your receivers, the whole system is built with safeguards. Most of the ports on the splitter have built-in DC blocks that stop voltage from coming across the cable into your receiver. That’s a good thing. However, one of those ports needs to pass the power through… or else it can’t get to the dish!
That port that passes power has a red center to let you know that it has extra capabilities. The power inserter needs to be plugged into a red port, but if you already have the power inserter plugged into another splitter, you can use the red port for anything you need. (You don’t need a second power inserter just because you need another splitter.)
So now maybe you’re asking, if I plug a receiver into that red port, why doesn’t it fry since power could flow through it? The answer is simple. DIRECTV splitters are designed so the power flows “up” through the splitter toward the dish, not “down” to other splitters. So you’re completely safe.
HR54 and HS17 Genie DVRs
These two DVRs have a special extra superpower- they can power a dish as long as there is no external multiswitch. So everything I just said above doesn’t apply, if you want to run your system this way. You would plug the DVR into the red port, to let it power the dish. The upside is fewer cables and boxes, but the downside is that nothing works at all until that DVR powers up. So, if you have additional receivers on your system like H25s, they won’t work until the Genie DVR is ready.