When not in the navigation mode, the arrow buttons all take on a different purpose, bringing up keystone correction. BenQ emphasizes that while we serious enthusiasts avoid using Keystone correction because it diminishes image quality, they point out that the kids just won't notice.
With keystone correction you can do some creative placement of the projector, for example having it lined up near the right side of the screen, rather than with the center. Use it if you must, as it does soften/degrade the image.
My only complaint is that BenQ didn't need to make all four arrow keys capable of bringing up the keystone correction menu. A better design would be to have two of them handle volume Up, and Down. And perhaps use just one for Keystone correction, and the last one for toggling between Basic and Advanced menus? (Sorry, just thinking out loud!)
HT1075 Inputs and Connectors
Let's consider all of the BenQ's connections on the back panel. We'll start on the far left, with the pair of HDMI inputs. Note that HDMI2 is the one that supports MHL, and therefore can accept a Roku stick, some Android tablets, and other MHL devices, which essentially make this projector "smarter". MHL is primarily used for streaming content.
Next over is a 12 volt screen trigger for controlling a motorized screen (or some other function). A pair of USB ports comes next. The USB - A can be used for sources, while the USB - B type is used as a service port for the projector.
Next is an HD15 connector - your standard connector for analog computer sources, and often called a computer input, or VGA input, while below it is a DB9 connector which is a serial RS-232 port, normally used for "old school" command and control, such as controlling this projector from a room control system such as Crestron, Control4, etc.
The six RCA jacks that come next consist of R,G, and B which make up your component video input, and a Yellow one for composite video while the white and other red jacks are for stereo audio input.
Finally, on the far right are two more jacks, both stereo mini types. The upper one provides a second stereo audio input (I'm not counting HDMI inputs which also carry sound), while the lower one is a stereo audio out.
Time for me to complain about the stereo audio out. Like just about every other manufacturer sporting a stereo audio out, BenQ got it wrong.
When you have a projector like this, with one or two internal speakers, and you want to watch a movie, the speaker system may have the volume to do good job, but let's face it, there's no chance of the kind of wall rattling bass that one should have with most action flicks (or, for that matter, music videos).
But the BenQ when you plug a jack into the Audio out, it turns off the internal speaker, and that's the problem. On or off should be a user choice. If this BenQ had that, I'd be able to recommend to everyone to go out and spend say $50 for a small, powered subwoofer, to complement the internal 10 watt speaker, and provide some of that wall rattling bass. Instead, you have to feed the output to a complete sound system to get that extra bass.
BenQ, if you are reading this, how about you get it right next time (and you competitors as well). Who knows, perhaps that could even be a firmware fix.
It should be noted that the back panel also has a power receptacle, and a Kensington lock slot for security.