In article ,
Mark Lloyd wrote:

That reminds me of the "ring control"cords" I've used in the past.
These consist of a DPDT switch and a full-wave rectifier. When only DC
is passed to the phone it works but won't ring.

I hired-on as one of Omaha's first, male long distance operators with the old
Northwestern Bell Telephone Company. Affirmative Action was 4-months old.

The job was right out of The History Channel: 20-30 of us, elbow-to-elbow, on
non-padded (wicker seat) chairs plugging cords into jacks on a half-block
long, black switchboard. I began wearing the "modern" (Mercury 7 era)
headset. It was eventually replaced by a Plantronics "Starset".

It was a trip. After several INCREDIBLY boring months of this, I amazed all
the women that had been plugging-away for 30 years, and had never seen such a
thing, by drawing an half-inch long ARC by leaning on the ringing key and
using another cord as the ground. Ahhhhh, the good, old days...

TeleTrivia: Although the first telephone operators were men, they were
eventually replaced by women because women were less likely to swear at the
customers or whittle on the switchboard.
--

JR