Maptwin: an 80s-era automotive navigation computer
A couple of years ago, I imported a Japanese-market 4*4 van into the US; a 1996 Mitsubishi Delica. Based on the maps I found in the seat pocket and other clues, it seems to have spent its life at some city dweller's cabin in the mountains around Fukushima, and only driven occasionally. Despite being over 25 years old, it only had 77,000 km on the odometer.
The van had some interesting old tech installed in it: what appears to be a radar detector labeled Super Eagle 
30" and a Panasonic-brand electronic toll collection device that you can insert a smart card into. One particularly noteworthy accessory that was available in mid-90s Delicas was a built-in karaoke machine for the rear passengers. Sadly, mine didn't have that feature.
But the most interesting accessory installed in the van was the Avco Maptwin Inter, which I immediately identified as some kind of electronic navigation aid, about which there is very little information available on the English-language internet.
When I first saw the Maptwin, I had thought it might be some kind of proto-GPS that displayed latitude/longitude coordinates that you could look up on a paper map. Alas, it's not that cool. It was not connected to any kind of antenna, and the electronics inside seem inadequate for the reception of a GPS signal. The Maptwin was, however, wired into an RPM counter that was attached between the transmission and the speedometer cable, presumably to delivery extremely accurate and convenient display of how many kilometers have been traveled since the display was last reset.
What I've been able to learn is that the Maptwin is computer that was mostly used for rally race navigation, precursor to devices still available from manufacturers like Terra Trip. Now, the Mitsubishi Delica is about the best 4*4 minivan you can get, but it's extremely slow and unwieldy at speed, so it would be pretty terrible for rally racing. My best guess is that the owner used this device as a navigation aid for overland exploration, as the name Maptwin" implies, to augment the utility of a paper map. On the other hand, I found an article that indicates that some kinds of rallies were not high speed affairs, but rather accuracy-based navigation puzzles of sorts, so who knows?
The Maptwin wasn't working when I got the van, and I don't know if it's actually broken or just needs to be wired up correctly. If any OSNews readers have any additional information about any of the devices I've mentioned, please enlighten us in the comments. If anyone would like to try to get the Maptwin working and report back, please let me know.