Wow, I've seen some pretty bad ones, but this is worse. The pipe and sealing in the house are probably a joy, too.

:gasp:

Stay tuned: I am going to visit the property soon!

Not sure where or how (or if) this connects to the house, as this box is about 25 ft away from, and 15 ft lower than the back of the house!

I would be interested to see if you put a fan on it what the static pressure would be or if there is any pfe below the slab.

That looks like an early system installed in the mid 80s. I've seen a few of those in the Richmond, Virginia area. The ones I've seen are vented quite some distance away from the house, typically in the woods. There was a lot of digging and trenching involved...... We've come a long ways baby!

It was not unusual to connect to a footing drain where it day lighted in the early 90s.
Typically a PVC T was installed so the fan could be mounted vertically and a 4" check valve was installed downstream of the T. I attended certification class in 1990 that demonstrated that type of system on the field trip. The enclosure was a little more professional.