Ok lets all help to reboot this dinosaur and get a couple of barrels of oil out of it!! I don't know much, but know enough to be dangerous...
GND 10 and 20 GND -- Connect both of these pins to ground.
Batt 9 and 19 Batt -- Connect both of these to the +12V, +13.8 or +14.4V DC car battery or benchtop power supply. Be sure your bench top power supply can supply 5A to 15A of current if you turn up the volume. This power should be constantly on (ie. to the battery and not to a switched power line).
ACC 8 and 18 ACC -- This is the switched Accessory line in your car. Normally it's 0V/ground when you remove the key from the ignition. When you stick the key into ignition and twist/switch it to the Accessories position, or when the motor is running, this line becomes +12V/+13.8V/+14.4V. For indoor bench tests, hook this pin/line to a switch and this switch to your 12V power supply. Flip this switch to pretend you turn the ignition key.
REM 7 -- This is the Remote output line. Normally, people hook this line to a relay and then to the automatic antenna or the remote/turn-on line of the external amplifiers. Note that this is an output line and not an input line. You can leave this open/unconnected too. Hint... With the use of a relay (to supply larger current), this signal may be used to trigger/supply power to your reverse camera.
17 Dimmer -- This is the Dimmer line for those lights on the dashboard at night. Some headunits accept an analog/variable voltage input. When the voltage is higher, the lights on the dashboard becomes brighter and so will the display on the headunit. Sometimes it's the opposite on other headunits. When you turn on the headlights (and dash lights), it sends the appropriate voltage (either 12V or ground) to this line and will make the display/screen darker. All this is so that the screen does not light up the car's interior at night and we can't see the road ahead. You will have to experiment with this line to characterize your Alpine's feature (have to hook to the dimmer or dash lights line in the car). You can leave this open/unconnected too for initial tests.
G-Cont -- Must be a bus pin. Leave it open - do not connect to anything.
16 Park -- This is an input pin and goes to the Park wire on an automatic transmission. The Alpine lawyers and the traffic enforcement authorities don't want you to watch videos when you're driving. The video is only supposed to only work when you're safely parked (vehicle is stationary). For cars with a stick shift (manual) transmission, some people hook it to the parking brake signal. Ha ha you'll also never be able to watch the reverse camera if you're moving backwards. The workaround is to hook this to your reverse/backup light circuit. Depending on its polarity, you may have to add a relay to invert the signal. For bench tests, hook this to a switch and then to the 12V battery. This is to view if the video shows up on the screen. If it doesn't work, unhook this switch from the battery. Now the same line/switch goes to ground for tests. (Please read carefully - remove the connection from battery, then hook that switch to ground - not hook the positive battery line to ground which will cause a big problem.) After this you'll know which way to hook it up with the reverse light in your vehicle (with or without a relay to invert the signal). Of if you just want to watch the rear view all the time, hook it to a switch (either powered or grounded) and not mess with the reverse line/back-up light line.
D-Cont 5, 15 Mod-Cont, Bus+ 4, 14 Acc-Cont, Bus- 3, 13 B-Gnd, pin 2 and pin 12 -- Leave all these open too.
Video 1 -- This is an input. Hook this to the camera's video signal. It should be a standard composite video signal. Your camera should have a separate power input too.
V-Gnd -- Hook this to the ground of that video/camera's signal. It has a separate V-Ground (instead of going to the normal ground so that the signal is cleaner).
# include standard disclaimers here. I cannot be responsible how it turns out, but like to see it a success. (I'm probably unable to provide more info than the above here.) Good luck and have fun.