When I went to college I operated the college telephone cordboard for extra money. All manual, even party lines with special rings like two short and one long. I enjoyed every minute of it! So much so I spent 20+ years in the telephone industry.
Since there is so much interest in the old analog electro-mechanical phone network, check out this Youtube site by Evan Doorbell who made thousands of hours of recordings of the network when he was in high school.
And finally for a bit of nostalgia this link will take you to a stereo recording of the sounds of a step CO. Here is the text that accompanied the file.
Inside a Bell 355A step CDO in Brunswick, Md (March, 1984)
Phone tripper Trace McCall sent us a recording he made inside a step by step central office, and he promised to send us more. The pulse repeating followed by the loud chattering was a CAMA trunk MF sending to the Frederick Tandem office. At the beginning of the segment, in the background you can make out a "snoring" sound. That's a linefinder group running a switchman-started test.
Jim - KD9DO