On Sunday, April 28, 2019 at 8:25:39 PM UTC-4, wrote:

They certainly only looked like a carbon/graphite rod that connected
the signal lines to ground to me. I suppose you could "fire" them up
but they were still just resistors that bled static off the line. I
may still have one here somewhere because that was what UTS was using
here until Sprint gave me a new Dmark. I doubt I threw it away. As
long as I was just using old school phones I didn't care but when I
hooked up a modem I had them change the protection.

They, in their new state, were just high resistance carbon rods. But they didn't bleed off static. They were primary lightning protection that basically shorted when the big lightning spike came in. That's how they bled off the big spike. It certainly wasn't because they were a high resistance resistor. They gave their lives to protect the equipment.

In the old days after a storm, and your phone didn't work or had a big hum on it, that's what the repairman changed out on the box on the outside of your house to fix it. That's what carbon protectors do.