HC3500 Inputs and Connectors
The Home Cinema 3500 is rather well equipped with inputs, etc.
Of course you can see the grills for the two 10 watt speakers on either side of the connectors.
Starting from the left top are a pair of HDMI inputs. HDMI 1 supports MHL. Moving down, on the far left is a 12 volt screen trigger suitable for controlling a motorized screen or some other devices. To the right of the trigger is an HD15 connector for an analog computer input (labeled PC), and right below it, an RS232 serial port for "old school" command and control.
Moving further to the right you'll find a yellow RCA jack for composite video and below it, a pair of RCA jacks (red and white) for the matching stereo audio. Next up (to the right and above) are three more RCA jacks, this time color coded red, green, and blue. Those are the component video.
Up next to the right is a small USB-mini jack which is the Service port. I used a similar connection recently on the HC5030UB to upgrade the projector's firmware. Next to it, is a USB Type A.
Just below is a stereo audio output (handy for "exporting" audio to an external stereo or surround sound system). Note that if using MHL, (or HDMI), audio comes over as well as video. If you are watching a movie, let's say, on Netflix, coming in on a Roku stick, and wanted bigger sound than the projector has, use the Audio out.
Every time I look at the functionality of an Audio out on home projectors I have the same old complaint. Plugging in a cable to run to your audio system turns off the internal speakers. Bummer, because if they could keep playing, then one could just plug in a small powered subwoofer to massively enhance the bass when watching movies, sports, etc.
That leaves only the Kensington security lock slot, the rear IR sensor for the remote control, and, of course, the main power receptacle.