I must, like last year, offer congratuations to Panasonic for the PT-AE4000 having three HDMI inputs instead of the usual two. Most people won't care, but some with more HDMI sources than their AV receiver or HTPC can support, need extra HDMI inputs, and the Panasonic's three, should do the job, whereas most offer only two HDMI inputs.
The image above of the input/output panel is of the PT-AE3000. This image will be replaced shortly with the PT-AE4000 image, which is laid out the same but for the addition of two screen triggers.
In addition to the HDMI 1.3 inputs there is a computer input to the immediate right. That is followed by a pair of color coded (separate R, G, B, RCA jacks) Component Video inputs. Then, of course, the usual S-Video and Composite video inputs (one each). Finally, there is an RS-232 port for controlling the projector from a computer or room control system. There is also a Kensington Lock slot, the rear infra-red sensor for the PT-AE4000U remote control, and the power cord receptacle.
This year, the PT-AE4000 supports CEC for room control type setup, and that's something the PT-AE3000U did not do.
Also new for this year are the two 12 volt screen triggers, which can be used as input or the more traditional output switching. Considering Panasonic's "thing" with fancy lens controls (I do like the Lens Memory option), that makes sense.
In this day and age, most projectors have a single trigger, a few have two, and some have none. While convenient, they are not critical, as the types of devices normally controlled, like lowering or raising a screen, triggering an anamorphic lens sled, a screen masking system, or even just powering on and off other components, can be controlled with 3rd party "universal" remotes, room control systems, etc. In other words, definitley a nice touch, but one most people won't need to have.