if you want to see how complex and overbuilt it is, https://www.youtube.com/c/ConnectionsMuseum https://www.youtube.com/c/ConnectionsMuseum has coverage of all

if you want to see how complex and overbuilt it is, https://www.youtube.com/c/ConnectionsMuseum https://www.youtube.com/c/ConnectionsMuseum has coverage of all the old PSTN equipment you could ever want i can't claim to _understand_ it half the time, but there are big rows of mechanical automatons galore