>>I couldn’t believe I’d never noticed it!<<
Interesting, huh?
I was telcom manager at a major So Cal University for a while and learned all kinds of interesting stuff. Telcom lore is a lot of fun and more arcane than people know.
I still have, and can use, a toner to backtrack wiring — as well as Fluke meter to do distance, impedance and the like.
“Telcom lore is a lot of fun and more arcane than people know”
I know that in NJ at least there are a bunch of “telephone pioneer” clubs, I guess they are made up of folks that were in “telecom” before it was “telecom”!