One ringy dingy

   This story was related by someone in Winnepeg, Ontario about 
a repair call he handled while living in England.  It's common 
practice in England to ring a telephone by signaling 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.  Pat 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, Pat found:
  
a. A 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.