I wasn’t familiar with stove-pipe terminology used for waste disposal systems. From what I was able to dig out (not much information about the stove sanitary drains) is tapered and inserted into the other one, and so on. Unlike two sections of PVC pipe which require a coupling to join them together.
The sanitary sewage lines are equipped with manholes that serve as an inspection access point and sewer gasses ventilation port. They pretty much play the same role as the vent stack
in the home’s plumbing system.
Let me know if this helped and if there’s anything else I can help you with.