I worked on a project that replaced an electromechanical Telex switch. Four racks of microcomputer based hardware replaced an entire floor of mechanical relays.
However it was a marvel to see and hear that thing click and clack all day, with technicians with their ear trained to detect issues and replace relays by listening to the switch.
Of course billing was done through a guy on top of a ladder taking large format B&W pictures of the bank of user's (mechanical) counters.
I wish I had. That was my first job out of school, and I developed the UI for commands and reports, all through the BAUDOT-code based terminal. Our field test switch sat on a corner, with some more modern electronic telex terminals (they were blue), along with EPROM burners for patching, etc. The big switch was the rest of the floor. So many things I participated in 30+ years ago and didn't have the idea of taking at least a couple of pictures. Such is life.
However it was a marvel to see and hear that thing click and clack all day, with technicians with their ear trained to detect issues and replace relays by listening to the switch.
Of course billing was done through a guy on top of a ladder taking large format B&W pictures of the bank of user's (mechanical) counters.