ECN Forum Forums General Topics of the Trade General Discussion Area Phone troubles

An elderly lady phoned her telephone company to report that her telephone failed to ring when her friends called - and that on the few occasions when it did ring, her pet dog always moaned right before the phone rang. The telephone repairman proceeded to the scene, curious to see this psychic dog or senile elderly lady.

He climbed a nearby telephone pole, hooked in his test set, and dialed the subscriber's house. The phone didn't ring right away, but then the dog moaned loudly and the telephone began to ring.

Climbing down from the pole, the telephone repairman
found:
1. The dog was tied to the telephone system's ground wire via a steel chain and collar.
2. The wire connection to the ground rod was loose.
3. The dog was receiving 90 volts of signaling current when the phone number was called.
4. After a couple of such jolts, the dog would start moaning and then urinate on himself and the ground.
5. The wet ground would complete the circuit, thus causing the phone to ring.

Which demonstrates that
some problems CAN be fixed by pissing and moaning.

... That was hilarious,..was it a true story??,....it had to be, ya can't make that stuff up...

Suppose:
- single conductor from street, return is via earth
- earth wire from phone connects to metal stake
- stake is driven into ground of poor conductivity (e.g. dry)
- dog's chain attached to same stake
- dog lays on slightly damper patch of ground (because it's cooler?)

48V DC doesn't cause dog any concern.

Phone rings - initially earth wire->dog->ground is lower resistance
than earth wire->stake->ground, and dog gets jolted by ring voltage
(90V AC superimposed on 48V DC, which _does_ cause him some concern).
Dog pees, ground around stake becomes damp, stake->ground resistance
drops below dog->ground resistance, dog ceases to be significant part
of circuit, and sufficient current flows for ringer to do its thing.

The story makes some sense if you accept the possibility of telephone
installations not up to current (or indeed within-a-couple-decades)
standards.

This is one of those stories that has been around with minor variations in the details for a long time.

The local ground rod connection would be used on either (a) a very old single-wire line, or more likely (b) a party line.