The
Telephone and the Dog
28-VII-2003
It's common practice in England to ring a telephone by sending extra
voltage across one side of the two wire circuit and ground (earth in
England). When the subscriber answers the phone, it switches to the two
wire circuit for the conversation. This method allows two parties on the
same line to be signalled without disturbing each other.
An elderly lady with several pets called to say that her telephone
failed to ring when her friends called; and that on the few occasions when
it did ring her dog always barked first. The telephone repairman proceeded
to the scene, curious to see this psychic dog.
He climbed a nearby telephone pole, hooked in his test set, and dialled
the subscriber's house. The phone didn't ring. He tried again. The dog
barked loudly, followed by a ringing telephone.
Climbing down from the pole, the telephone repairman found:
1. The dog was tied to the telephone system's ground post via an iron
chain and collar.
2. The dog was receiving 90 volts of signalling current.
3. After several such jolts, the dog would start barking and urinating
on the ground.
4. The wet ground now completed the circuit and the phone would ring.
Which shows you that some problems can be fixed by just pissing on
them. But only temporarily. |