Crap! Here I thought this was a thread showing a bunch of samples of the pair!
Anyways...If I recall correctly, the 8 pin type contact came out with the Maxxum 7 and later versions of the Maxxum 9. It was dual purpose. First, I believe that it was to allow the 7 and 9 (and later bodies) to communicate with the new SSM lenses. This would definitely affect focus. Second, it allowed feedback from SSM lenses as to focus distance. This is how ADI works.
Back in the old days, flash photography involved taking measurements from film plane to subject, then doing the math as far as light falloff at that distance with the light output of the flash being used. Minolta then came forward with TTL OTF flash. This was cool. The flash would fire and the light would reflect off the subject, entering the lens and exposing the film. While this was occuring, a small portion of the light would reflect off of the film onto some sort of sensor. When the sensor received the correct amount of light, the flash was extinguished. While this works wonderfully, Minolta decided that their onboard computers were now quick enough to quickly read the focus distance of the lens, set the correct flash exposure and fire the flash without a serious lag time. They began to create new lenses with this "ADI" capability.
The added 3 contacts, I believe (and I could be completely wrong
) work with ADI and SSM both.
EDIT: Just as a post thought...ADI only works when the flash is fired directly at the subject, such as an onboard popup flash or an accessory flash pointed straight ahead. If an accessory flash is used wirelessly, in bounce mode, or in swivel mode, ADI does not work. The Flash tells the camera that it is wireless or that it is not pointed straight ahead. At this point, the camera body changes the flash type to TTL pre-flash. What happens then is a very short micro-burst is sent prior to exposure. The camera body measures the light that is reflected off of the subject during this pre-flash. It then sets correct flash output and the shutter is opened, the flash is fired for a correct exposure and the shutter is closed. This all happens in milliseconds.
I hope this helps. By the way, most of this can be found by looking up Gary Friedman Archives on the web, then searching his free articles on the Minolta Flash System.