I was rechecking the Atari 7800 expansion port story on AA and I read the story again, and I'm amazed to find that I have a console that potentially could handle external video signal from other equipment such as a Laserdisc player. I read the pinout chart that is already there, and I got the idea of checking myself the pins with a multimeter. I found the actual Audio and Video pins, and they go directly to the output Audio and Video signals of the console. They mix and output to TV. I don't need to test them as I have my console modified for AV output without a RF Modulator. The rest of the pins are routed directly to the MARIA chip. The Atari 7800 could've put to the same level as the MSX computers and the japanese Sega Megadrive if only Atari could've pushed for the Laserdisc technology.
I'm going to clarify one thing about the Video signal: I'm not sure what's going to happen with the video signal. I'm pretty sure that the audio signal might mix but that's just speculation.
they used Philips Laser disc units, they were normal LD units for home entertainment, but the laser games need LD units that can resist a lot of stress for long periods of time... probably Atari choose Philips "non Hi-Fi" units bcs there were a lot of service points, especially in Europe, while the more relaiable japanese units had no market and no stores outside Japan, the same market where Atari's games had no success at all.
LDs were expensive tho. They came in around 1k in 1983/84 which is nearly 2700 today. That's a very VERY expensive peripheral - for a very limited library of games (as others like Halcyon from RDI and Pioneer's LaserActive system which even in 1993, cost over 1800 in today's dollars would immediately discover). Presumably you could also watch movies - but at a premium price. I'd also heard rumors that Atari considered using the CED systems (which were discontinued in the spring of 84 but had a premium unit capable of random access - used in Bally-Midway's NFL football - but at a fraction of the price of an LD player). In-fact, from 1981-1985 our family enjoyed the CED system specifically because it cost a fraction of VHS/Betamax tape systems and the movies were in the 15-20 dollar range where tapes weren't mass produced in volume enough to cost less than 80-plus (80s dollars) a pop. We could also rent CED movies for 3-5 dollars a night vs 2-3X that for a VHS rental. So it wasn't a bad deal before cable TV became wide-spread and the cost of tape-machines and tape-movies came down (which they really didn't until the end of the 80s and the early 90s). CED players were the first to get stereo playback vs VHS and in an odd twist of licensing - had an exclusive lock on Star Wars' home release over tape (for a year if memory-serves). So it had it's perks along it's brief lifespan.
I doubt anyone would have been able to afford the expense of a laserdisc machine for the 7800. They were not cheap at a cost of $1000 or so. Would have been very niche indeed.
I wonder if anyone can make something that uses that expansion port used with the early Atari 7800 units but removed with the later units, time will Tell. (9:46)
I'm three blocks from MIT and there actually is a computer lab that uses cds and laserdiscs on the outside brick spelling out advanced computer research division, like fifteen feet high by about 20.....I'll work on converting it to meters for u lol