That takes us to the back of the HD4000 projector. There are a couple of minor surprises in terms of inputs. Let's start with the basics - from left to right:
There is a digital HDMI input, and next to it a standard HD15 connector for traditional computer analog signals. Alternately, that connector can be used to feed the HD4000 a component video source.
Below these two are a serial port for "command and control" of the projector by a computer, and a USB port. Moving to the right side at the top, is a separate component video input, so, overall, you can have a digital source, an analog computer, and a component video source all hooked up at once, or several other combinations using the same three inputs. You will also find below the component video (3 RCA jacks), the tradtional S-video and composite video inputs.
The other two items are the rear Infra-red sensor, and a 12 volt trigger for controlling properly equipped motorized screens. Having the trigger lends me to believe that Mitsubishi sees the HD4000 as a projector that will often be permanently ceiling mounted for business, matched with motorized screen, or being used for home theater, or, of course designed with both in mind. To round out the back, there is only the AC power recepticle.
I should note here, that the HD4000 uses a "sealed light path" no dust or dirt can get in between the lamp, dlp chip, color wheel and lens.
Hot air vents out the front, angled away from the lens. This makes the HD4000 suitable for mounting on a rear shelf, if the throw distances work with your room depth and screen size.
That pretty much covers the basic hardware. We'll look at the remote control in the Performance section.
Time to explore the HD4000's image quality. In this case we will consider it's capabilities for both business/education related use, and separately as a "bright" home theater / entertainment projector.