AN IMPROVED METHOD AND APPARATUS FOR EFFECTING TELEPHONIC COMMUNICATIONS
Year: 1881

page_text: LETTERS PATENT to John Imray, of No. 28, Southampton Buildings, Chancery
Lane, in the County of Middlesex, for an Invention of "AN IMPROVED
METHOD AND APPARATUS FOR EFFECTING TELEPHONIC COMMUNICATIONS."
A communication from abroad by J. Milton Stearns, junior, of the City of
Brooklyn New York, United States of America,
PROVISIONAL SPECIFICATION left by the said John Imray at the Office of
the Commissioners of Patents on the 12th October 1881.
JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the County
of Middlesex. "AN IMPROVED METHOD AND APPARATUS FOR EFFECTING TELE-
PHONIC COMMUNICATIONS." [A communication from abroad by J. Milton Stearns,
junior, of the City of Brooklyn, New York, United States of America.]
For telephonic communication a number of subscribers usually have their instru-
ments connected by line wires to a central station or exchange, where an official
on being called by one subscriber puts his wire in connection with that of another
subscriber with whom the former subscriber desires to communicate. This Invention
relates to an arrangement of the line wires and their connections at the exchange,
and a method of operating there with so as to facilitate the making and breaking of
the telephonic connections, and to produce appropriate signals guiding the official
in his duties. A vertical board has fixed on its face a number of horizontal strips
of metal, each of which is termed a "level" There is a number of holes through
the upper level and through the board backing it, and on each of the lower levels
there is a corresponding number of projecting hooks or pegs. As there is a hole
for each subscriber, when the number of subscribers is large it is convenient to
make the board and its levels of concave, semicircular, or polygonal form, so that
the official occupying the centre can reach the different holes and pegs. The line
wire of each subscriber being brought to the back of the board, is connected to a
helical spring and flexible metallic cord clothed with insulating material, which is
passed through one of the holes in the board and upper level, and attached to a

page_text: ring. The spring keeps the ring in contact with the level, but admits of the ring
being pulled down and hooked on to a peg on any of the lower levels. Any two of
the subscribers can thus be put in communication. The official when called by the
one pulls down the ring belonging to that subscriber and hooks it on to a peg, and
he then pulls down the ring of the other and hooks it on to a peg on the same level
as the former; this level or metallic strip then constitutes the electric connection
between the wires of the two subscribers and the line battery. The top lovel is in
contact with an instrument which, in order that it may always be ready, is most
conveniently strapped or otherwise fixed on the official's head, presenting itself to
his ear; consequently when any subscriber calls, his ring being in contact with the
top level, the official hears and inakes the connection desired, or if he cannot then
make the connection, he so informs the calling subscriber by means of the exchange
telephone. The first effect of making the connection is to cause three electric bells
to sound, namely, that of the subscriber who calls, that at the exchange, and that of
the subscriber called. When the two subscribers take their telephones into use, the
increased resistance introduced causes the bells to cease, and thereupon the sub-
scribers communicate, the official not hearing what is said. When the subscribers
put aside their telephones the resistance is taken out of the circuit, and the bells
again sound, whereupon the official detaches the rings from the pegs, and the
springs draw back the rings to make contact again with the top level.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Imray in the Great Seal Patent Office on the 11th April
1882.
JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the County
of Middlesex, "AN IMPROVED METHOD AND APPARATUS FOR EFFECTING TELE-
PHONIC COMMUNICATIONS." A communication from abroad by J. Milton Stearns,
junior, of the City of Brooklyn, New York, United States of America.
For telephonic communication a number of subscribers usually have their
instruments connected by line wires to a central station or exchange, where an
official on being called by one subscriber puts his wire in connection with that of
another subscriber with whom the foriner subscriber desires to communicate. This
Invention relates to an arrangement of the line wires and their connections at the
exchange, and a method of operating therewith so as to facilitate the making and
breaking of the telephonic connections, and to produce appropriate signals guiding
the official in his duties.
The accompanying Drawings shew the arrangement according to this Invention
of the switch-board and its connections for use at a telephonic exchange. Fig. 1 is
a front view, and Fig. 2 a back view, and Fig. 3 is a vertical section. P¹, P³, &c.,
are wires leading to the instruments of different subscribers. Although the board
is shewn as for 8 subscribers, it might be extended to suit a greater number. When
the number is large it might be of circular form, in plan as shewn in Fig. 4, the
official occupying the centre O; or instead of being circular it might form a
number of sides of a polygon extending round or partly round O. At the back of
the board each of the wires P¹, &c., is attached to a spring S¹, &c., or to a weight
Ws, &c., and continued above these as a flexible conductor C₁, &c., covered by silk or
other smooth and flexible material, which passes through a hole at the top of the
board, preferably over a pulley, and is attached to a metal ring A¹, &c., having
a collar, which by the strain of the spring S or weight W is pulled against an
insulated metal bar T, so that all the wires P are normally in complete electrical
contact with this bar. Besides the upper bar T there are on the front of the board
a number of insulated bars D with metallic pegs or hooks d projecting from them,
so that any of the rings A can be drawn down and hooked on to one or other of
the pegs or hooks in line with it, thus putting the wire P in each case in electrical
connection with the bar D, on a peg of which the ring is hooked. In Fig. 1 the
ring A¹ belonging to the wire P¹ is hooked on a peg of one of the lower bars D,
whilst the ring A belonging to the wire P3 is hooked on a peg of one of the upper
bars D. Immediately on releasing the ring from the peg, the weight W or spring S
causes the ring to ascend and again make contact with the bar T. This bar T is
connected, as shewn diagrammatically in Fig. 5, through a call Q and telephonic
receiver R to the battery B, and the receiver R being always kept near the ear O of
the official (which is best done by having it tied or otherwise secured on his head),
when any subscriber signals, the official receives his signal and according to his
directions puts him in communication with another subscriber. For example, if the
subscriber No. 1 signals that he desires communication with No. 5, the official
pulls down ring A' and hooks it on to a peg on any one of the bars D, and also
pulls down ring A' and hooks it on to a peg of the same bar, the two subscribers
1 and 5 having their wires thus put in connection and all others as well as the
official being excluded.
When this mode of connecting subscribers is adopted, the official has to be
specially informed when their communication ceases, so that he may unhook their
rings. In order to avoid the necessity for such special notice to the official the

page_text: arrangement shewn diagrammatically by Fig. 6 may be adopted. The bars D¹, D³,
being connected together through an alarm bell H at the central office, two
subscribers, as for example, No. 2 and No. 3, are put in communication by hooking
their respective rings A² and A³, one on each of the two bars D1, D2, connected as
above mentioned. When the rings are thus hooked on, the bell H sounds and
also the bells of the two subscribers, and these bells would go on sounding as
long as the receiving instruments R² and R³ continued bung in their places,
shewn in Fig. 6, in which positions they are arranged to short circuit their
-respective lines. When however the subscribers take down their instruments R²
.and R³ in order to apply them to their ears, the additional electrical resistance
thus introduced in their lines causes all the three bells to stop sounding. When
again the subscribers hang up their receiving instruments the bells begin to sound
again, and the official hearing the bell H knows that the telephonic communication
of the two subscribers is at an end, and he consequently unhooks the rings A*
and A³, thereby disconnecting the subscribers, and also the bell H.
Having thus described the nature of this Invention, and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I
claim in respect of means for effecting telephonic communication at a central
station or exchange,―
First. The method of connecting the wires of subscribers' instruments with that
of the official or with each other by providing each of the wires with a weight or
spring, and with a collar ring or its equivalent for making electrical connection
with one or other of a set of insulated bars on a switch board, substantially as and
for the purposes herein set forth.
Second. The construction and arrangement of the switch board with its insulated
bars T and D in combination with the subscribers' wires P, their springs S or
weights W, flexible covered parts C and collar rings A, substantially as herein
described.
In witness whereof, I, the said John Imray, have hereunto set my hand and
seal, this Eleventh day of April, in the year of our Lord One thousand
eight hundred and eighty-two.