I received this from a (British)motorcycle list.
Gerhard Wiederholl
"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 signaled
without disturbing each other. Anyway, 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 dialed 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:
a. The dog was tied to the telephone system's ground post via an iron chain and
collar..
b. The dog was receiving 90 volts of signaling current.
c. After several such jolts, the dog would start barking and urinating on the
ground..
d. The wet ground now completed the circuit and the phone would
ring...
Which shows us that some problems can be fixed by just pi&&ing on
them. But only temporarily . . . . "
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