On Tue, 22 Jul 2008 19:24:34 GMT, "Eddie Bellass"
wrote:

Many years ago, when telephone lines were in
very short supply, 'party lines' were common.
A party line, officially known as 'shared service',
meant 2 premises sharing the same pair of wires.

Incoming calls to one or the other were separated
by arranging the 75 volt AC bell ringing current to
travel out via one or other of the pair of wires and
return to the exchange via 'earth'. This required
driving a metal spike into the ground and connecting
the bell's return path via 3-strand bare copper wire.

One day I was called to a farm which had reported
their dog howling in distress every time the phone
rang. We sometimes had a laugh at the wording of
some customer's reports but I went down to the farm
all the same. I asked the operator to ring me back
and sure enough, the dog gave first a little yelp and
then a painful howl. After a few trials I went out into
the yard to see the dog repeating the cycle, peeing
as it did so. This couldn't be a coincidence, nor was it.

The farmer had secured his dog with a new steel chain
fastened by an eyebolt to a flat steel bar spiked into the
farmhouse wall. In doing so he had broken the earth
wire for the telephone. Instead of the ringing current
going to earth via the spike it was travelling through
the chain and the dog. The tickling of the 16.333 cycle
75V AC made the dog pee and gave the return ringing
current an even lower resistance path to earth via its
bladder and its willie.

Given such circumstances, wouldn't we all howl? ;-)

Not so painful, but one day while I was doing my apprenticeship with
PO telephones, we received a "Fault for Special Investigation" form
for the local hairdressers. This was another installation using
earthed ringing (plan 107 = 1 main telephone plus 1 switched extension
at a different address) and the complaint was that it didn't work on
Monday and Friday mornings. We turned up on one of the appropriate
mornings and lo and behold it didn't work. Upon pulling out a few
hardboard panels to trace the earth connection we found that the earth
wire didn't go to any kind of proper earth connection but disappeared
down the shop's drain which on the day following the weekend or early
closing was dry and totally useless as a conductor.

"Older viewers" might remember manual telephones. One of the early
systems (Central Battery Signalling system No1 aka CBS1) also used an
earthed bell circuit (the "clear" signal was given by earthing one
side of the line via a low-resistance bell circuit) and in hot weather
subscribers would occasionally be asked to go out and water the ground
around the earth spike if they reported that their bell wasn't
ringing.