I have finally joined this group and hope to get and share lots of knowledge. My MADhouse Telephone Co is a 200 line SxS almost fully equipped with GTE/Automatic Electric gear. This includes access to C*NET via a GTE/Lenkurt T1 channel bank. Pictures of my switch and an ongoing history can be found on Facebook by searching MAD house Telephone. Also, videos have been published of the more unique items on YouTube under the same name.
ADavid
MADhouse Telephone Co.
https://www.facebook.com/madhousetel/
Dial Tone Delay Register (https://youtu.be/_LbROilbk7A)
The Automatic Line Tester (https://youtu.be/Wt1GGdDa5jQ)
The Audichron STM, history and how it works (https://youtu.be/0IHzWWMzqmI)
Had a look at your YouTube video on the Automatic Line tester. I've got one of those old "adding machine" printers. It was used in a Centrex (311?) Step office, possibly for the same purpose. I worked on the POTS step switches, but grabbed it when the Step Centex was removed about 1984. I modified it to print out outbound (9+) dialed numbers from my step switch, although that hasn't been used now for a while. Eventually, after a move, I may hook it up again.