St. Johnsbury Caledonian. [volume] (St. Johnsbury, Vt.) 1867-1919, 1891-11-12
THE UNDERGROUND TELEPHONE
SYSTEM IN NEW YORK.

The underground cable portion of
the telephone system in New York is
the largest plant of this description
in the world, and a detailed examina
ton of it will be we'll worth while.
Starting from a subscribers tele-
phone, we find near the top of the
blackboard a couple of terminals or
binding posts, to which pair of in
sulated wires are attached. These
wires are led to the nearest under
ground cable terminal. perhaps
there is a terminal in the cellar or on
the roof of the building, in which
case the wires are taken to it by a
secure route along the walls and
shafts. Perhaps the cable terminal
is on another roof in the same block,
or, in a neighborhood where there
are few subscribers, on gigantic
pole, to which air lines converge to
dive underground. Then a short
length of overhead line carries the
subscribers wires to the terminal.
The terminal itself consists of a
long iron box Theoretically sealed to
protect the cable from the inroads of
moisture, and provided, either on the
front or at the sides, with rows of
brass binding posts. To these bind
ing posts, which are insulated from
the iron case by sleeve of hard rub
Der, the wires of the cable are per-
manently attached within, and the
subscribers wires are connected on
the outsidein regular order, the bind
ing post thus forming connecting
link between the lines leading to the
oh,
foreground to the exchange. There is
another connecting link in the box,
which protects the cable terminal
from the weather, and this is the
lightning and strong-current pro-
tector. This little device is inserted
in the line before it enters the cable,
its special function being to protect
the lines and instruments from the
assaults of lightning and other va
grant and powerful currents which
sometimes stray into wires, where
they have no other mission than one
Of damage and destruction.
The underground cable itself is a
very important part of the telephone
system of today, and a great deal of
ingenuity, time, and money has been
of cable suita BILE for telephone work.
The telephone current is very deli
cate form of energy, and it has to be
surrounded by the best of conditions
in order that it may live and thrive
and put forth its best efforts. 1t
thrives best in the free air on top of
an eighty-foot pole, above trees,
whose leaves seek to lead it astray,
and far from other wires, whose
strong currents fain would tyrannize
over it, and substitute for its timid
undulationS harsh and unintell1gible
gruinblings and roarings and NUT
terings of their own. Forced under
ground, it is choked and muff1ed and
subdued, like human life in a dark
cellar or crowded tenement, and in
The revengeful spirit aroused by un-
cOnSenial surroundings it becomes
perverted. and INDUCES in "cross-
talk" with the neighboring wires, to
the close proximity of which it is I'M
willingly condemned. But under
ground, in cities at least, mun1cipali-
ties have obliged it to go, and tele-
phone men have had to make the
best of the situation.
ne Underground telepnOne CaDle
is made up of a large nurnber-gener-
ally one hundred-of fine copper
wires. Each wire is insulated by a
wrapping of cotton or paper, and
the insulated conductors are then
twisted together in pairs. This
twisting is done as a preventive of
induction or "cross-talk" between
wire and wire, as, if two wires are
parallel with each other for any dis
tance, a current travelling in one
will set up a current in the other by
induction. The fifty pairs of conduc-
tors are made up into a flexible
cable, which is inca sed in a lead pipe,
and the cable is made. Almost every
New Yorker has seen these cables be-
ing drawn into the subways under
the streets, and these operations
were illustrated in Harper's Weekly