I know I asked this a while back, but I'm stubbornly going to keep at it.
There are more than a few entities on fedi that are into standing up old phone networks, ranging from military field comms, business PBXes, even homelab ESS implementations.
But I can't find a dedicated hashtag for the life of me, so I'm going to pick one and run with it.
#OtherNetworks is a great catch-all for the more esoteric, #RetroLab is broad but you get the idea, and #HomeLab is *really* broad.
#Boost maybe? ❤️