Omaha daily bee., 1903-04-25
LAVISH TELEPHONE SERVICE
Gigantic Automatic Plant Beng Installed
in the Chicago Exchange
The HELLO" GIRL DISPENSED WITH
I~nsteuments By which Callers Make
Their own COnnections-Means
Of Indicating Busy Calls
and Breaks.

The perfection OF tbs automatic e1-
change IL a telephone Improvement which
will be accepted as a matter OF fact achieve.
ment, but associated with any other industry
this great Innovation would cause wide
spread comment and discussion. The con-
sentative electrical men and doubters Of
the practicabllity Of automatic exchanges,
says the Philadelphia Record, have been
quite sllenced by the successful operation
OF those In Fall River and New Bedford,
In this country, and In Berlin abroad. THIS
latter was installed under the auspices OF
the government and while merely an ex-
perimental exchange, vas SO successful
that 1t was purchased by the government
and added TO the imperial telephone sys-
tenn, The other exchanges named have been
In service for several years and are quito
As popular as the usual type. II not mUTs
Attention has been called to the remarka-
BILE preparations that are being made in
Chicago for the installation Of an auto
matte telephone system on a larger scale
than has heretofore been attempted or
deemed possible. It was alleged that the
automatic system might operate in mall
exchanges, but when It became necessary
10 multiply switches to the extent required
In a large metropolitan exchange, the cost
would be prohibitive. Contrary to expecta-
tton, the Chicago company has expended its
money lavishly in the best underground
construction, going to the expense of UNDER
mining the entire downtown section Of
Chicago with tunnels to carry the COM
pany's telephone wires. In many instances
these tunnels are large enough for miles
at a stretch almost to permit their use for
electric railways, and II was limited at first
that this was the ultimate purpose Of the
projectors.
Many miles of underground tunnel, meas
uRins seven feet six inches nigh, and six
User wide In the widest part, are ready to
receive the telephone cables. A tunnel car
ries the wires under the Chicago river.
Operating the Phone.
There Is a dial under the transmitter
containing a number Of finger holes, ten In
all. representing the digits from zero to
nine, and hence allowing any number to be
formed. The dial, which is locked while
the receiver is on the hook, ~revolves on a
pivot. To call a number, say 22-24, the
Ringer is placed in the No. . hole. and the
hial revolved until It reaches a stop pro-
Vided at the bottom. On releasing the dial
It returns to normal, being actuated by a
spring. This operation Ia repeated sue
cessively with 2, 2 and 4, after completing
which a push button Is depressed which
rings the bell of the subscriber wanted.
The impulses that are sent over the line
are selected by very ingenious switches at
the central, and by a system Of elimina-
ton all phones are cut out except the one
desired. About a second is required for the
manipulation OF each digit on the dial.
No "HeIlo Girls" Here.
The most unique part Of the system is
At the central exchange. where banks OF
switches similar to the one shown meet the
view instead of a room full OF busy tele-
phone girls. Withal, II Is not very large,
only measuring IS inches In height an
inches in depth and 4 inches In breadth. At
the lower part Of the figure will be seen
three banks Of contacts, containing 100 In
each group. The vertical rod seen at the
center Of the device has both a rotary and
a vertical movement. The two lower banks
serve only to select the ten and unit digits
that is. the last two digits Of the num-
Der. When "a Is called by som subscriber
on his dial, the rod Is lifted vertically by
the FIRST movement, which sends q current
over one eide OF the two-wire circuit, thus
raising the rod step by step to the proper
row Of contacts-iu this instance two. The
succeeding movement Of the callers dial
sends the current over the other side Of the
circuit. and this by means Of controlling
electro-magnets rotates the rod until the
coHtset arm reaches No. 4. thus effecting
IL oAA NbhhGNlAOhs "hNh NV NallN
hds ngs up his receiver after the conversa-
tldb. current is sent over both wires and
the seleetor rod falls back into normal po-
sition.
To secure connections In the hundreds and
thousands an extension Of the same prin-
ciple is provided. It has been found that
ten trunk lines are SUFFICIENT for sach 100
subscribers. The connecter switches are
arranged in groups OF 100 each, giving ia
a. 4 AAA L--
sJkpseriber calls a number In the hundreds,
sayS pa. the first movement Of the dial
selects through the ~selector switches. one
OF the lines feeding the 200 group. and the
following movements Of the dial complete
the connection, as already described. In q
10000 exchange there is simply q further
extension OF the same system, the initial
movement selecting the proper thousand
group. and 80 on as before.
II will Immediately be asked; Suppose
the called phone is busy7 Probably this
was one of the first problems encountered
by the inventors Of the system, and they
have solved It most adequately. Under such
circumstances the calling subscriber re-
eeives a buzz In his own phone. which In
dicates that the wire Is busy. The uppeI
bank of contacts in the ~seleetor switch q:
connected with this operator. Even the
contingency OF the subscriber leaving his
phone on the hook, so that be cannot b
reached by other subscribers. is provided
for. In such a case, II the subscriber dOei
not answer, and there is no busy signal
the trouble man" is notified, and he set
q bowler In operation. which calls thu
attention Of the negligent subscriber u
the fact that his line Is out OF service
This "howler" device merely vibrates tn
diaphragm OF the receiver very strongl!
and rapidly. making a peculiarly charac
~teristic sound. But there is still tn
ground and short circuit TO be taken car
OF. How Is a subscriber TO notify centra
that his wire IL In troubled As q matte
OF fact, Il b not necessary, as the con
dttion Of the line tells its own story an
calls the attention OF the repairman 3
the dihiculty. This is accomplished yer,
sngenionsiy. When a short circuit occur
an excess current is allowed to pas
through the selecting switches in the cen
trail exchange, This current blows a hea
coil. which operation releases a spring an
makes another contact, thereby lighting a
incandescent lamp on a 'tell-tale" board
sEl.A 49,. a. A. AnawaNaw ~ aoN