DIRECTV's SWM Technology is awesome. With just a pair of wires, you can run 16 receivers. But what if you have 17? That's kind of a pain, right? I mean that would mean another whole SWM switch, right? WRONG.
If you're willing to put up with a few compromises you can have up to 20 receivers (1 tuner each) on each SWM-16. The secret is the legacy ports on the side of the SWM-16. You can hook a receiver up to each port and it will work just fine! Of course, you won't be able to share programming, so these ports are really best used for those rooms where you are using SD receivers that wouldn't share programming anyway. Older HD receivers (not Genies or H25s) can also use the legacy ports but will need a B-Band converter.
When you set up these receivers on the legacy port, you have to tell them they are not on a SWM system. Go into Satellite Setup and set the Multiswitch type to "Multiswitch" not "SWM." Yes, they clearly are attached to the SWM but really the signal is just being passed through the SWM and these receivers aren't using SWM technology.
Confused? Here's a diagram to show you how it's done!
Click the image to enlarge.