They are banging away in the rooms adjacent to my office to remove a 1960s era telephone switching system. There are hundreds of these little capacitors (correction…) resisters that I think served to reduce the voltage down to what a 2 pair phone line would take. I dunno. I’m sure we have some senior phone company technicians in our MakerSpace community.
Thanks Ed, for finding the 1976 copy of Bell System Practices’ Special Services Consulting Guide and locating this little guy on page 238. That’s one fine piece of research!
