On Sat, 12 Jan 2013 23:53:52 +0000, The Natural Philosopher
wrote:

On 12/01/13 22:47, Rick Hughes wrote:
On 12/01/2013 17:48, Charles Fearnley wrote:


These cables can sometimes be a bundle of thin enamelled copper wires,
with
the varnish in different colours for identification.


That what is appears to be ...


worse sometimnes it 'tinsel' which is wires interspersed with fibres
good for flexcibility: almost impossible to solder at all

Early telephone switchboard cords had to be highly flexible and
durable. They consisted of very fine strands of tinsel (cadmium copper
or bronze) spun around mercerised cotton. It was then served with
layers of silk or rayon, then covered with soft cotton braiding.
The only practicable way of terminating these reliably was binding the
end with fine tinned copper wire formed into a loop, virtually
crimping it, to attach to the screw connectors of a "jack plug", or
crimping on a spade connector for the fixed end of the cord.

Later cords used tiny crimped brass eyelets at the plug end.

Certainly solder didn't come into it at all :-)

Obviously all three conductors of the cord were then lapped in soft
cotton and finished with a layer of glazed cotton of the correct
colour.

It all kept the cotton industry going!

--
Frank Erskine