IMPROVEMENTS IN TELEPHONIC APPARATUS
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine Lake
"
& Co Patent Agents, Southampton Buildings, London, for an invention of
"IMPROVEMENTS IN TELEPHONIC APPARATUS communicated to him from
abroad by Charles Edward Chinnock, of Brooklyn, New York, United States
of Amarios
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 23rd May 1882.
"
WILLIAM ROBERT LAKE of the firm of Haseltine Lake & Co Patent Agents,
Southampton Buildings London " IMPROVEMENTS IN TELEPHONIC APPARATUS
[A communication to him from abroad by Charles Edward Chinnock, of Brooklyn,
New York, United States of America.]
This Invention relates to telephonic apparatus and comprises the combination
in a telephone system, of a central office, a complete metallic circuit extending
between the central office and the places of business or residence of subscribers,
means in the central office whereby the subscribers may indicate to an attendant
there, that they desire to be put in communication with others, and means whereby
portions of said metallic circuit which extend between these subscribers and the
central office may be removed from the circuit aforesaid, the said circuit may be
closed at the place of removal and the subscribers thus cut out of the circuit may
be put into communication.
It also comprises the combination in a telephone system, of a central office, a
complete metallic circuit extending to the central office and to the places of
business or residence of subscribers, means in the central office whereby the
subscribers may indicate to an attendant there, that they desire to be put in
communication with others, and means whereby portions of said metallic circuit
which extend between these subscribers and the central office may be removed
from the circuit aforesaid, the said circuit may be closed at the place of removal
and the portions thus removed from the circuit may be united to form a private
complete metallic circuit affording communication between the subscribers to whom
the portions of the circuit so removed and united belong.

page_text: It also comprises the combination with telephone instruments in a central office
and at subscribers' places of business, or residence, of a complete metallic circuit
comprising pairs of wires extending between the central office and the several
subscribers' places of business or residence, means whereby any of the said pairs of
wires may be removed from the circuit, and means whereby on the removal of any
of the said pairs of wires the circuit will be closed at the place of their removal.
Preferably the means for closing the circuit will operate automatically on the removal
of the said pairs of wires.
It also comprises the combination with telephone instruments in a central office
and at subscribers' places of business or residence, of a complete metallic circuit
comprising pairs of wires extending between the central office and subscribers' places
of business or residence, means whereby any of the said pairs of wires may be
removed from the circuit, and connected electrically with another pair of the said
wires, and means for closing the said circuit at the point whence the said pairs of
wires were removed from it.
'
According to this invention I provide a number of telephone transmitters which
are severally located at subscribers' houses or places of business. These transmit-
ters may be of any approved kind.
A
The ends of the primary wire of the induction-coil of each transmitter are
connected by a wire with a battery and two contact pieces. From one end of the
secondary wire of the induction-coil, a wire extends to a telephone receiver.
wire extends from this receiver to the contact piece of a switch. From an opposite
contact piece a wire leads to one end of the wire of the electro-magnet of an
electro-magnetic call bell arranged on the box of the telephone transmitter. A wire
leads from the other end of the electro-magnet of this call-bell to a wire which
extends from the other end of the secondary wire of the induction coil to one of
the central offices. The switch consists of a metallic bar which is suspended by a
metallic spring at the upper end and is provided at the lower end with a hook on
which the telephonic receiver may be hung. To the switch-bar is attached a
metallic cross-bar having affixed to it, at one end, a metallic block which, however,
is insulated from it by a piece of insulating material. A wire extends from the
spring to the central office.
When the telephone receiver is hung on the hook of the switch-bar, the latter is
drawn down so that its cross-bar breaks contact with one contact-piece and makes
contact with another contact-piece and the block breaks contact with the other
contact pieces.
་
From wires adjacent to the telephone transmitter and receiver, branch wires
extend to contact pieces. A spring-switch connected with a ground-wire is
arranged adjacent to these contact-pieces and may be pressed against them by the
subscriber to establish communication between these wires and the ground wire.
These wires are provided at the central offices with flexible extensions which are
together enclosed in an insulating casing of any suitable kind and are connected
with plugs.
The plugs severally consist of two metallic terminal plates affixed to opposite
sides of a plug of insulating material; and their plates are electrically connected
with the flexible extensions of the wires. Except when subscribers are put in
communication with one another, the plugs are inserted in holes in a switch-board.
These holes are furnished with pairs of metal-contact pieces, which, when the plugs
are inserted in the holes, make electrical contact with their plates but which,
when the plugs are withdrawn, spring together, and make eléctrical contact with
one another. The contact pieces of each pair of contact pieces are connected by
wires with the contact pieces of the adjacent pair of said contact piecès. The
outer contact pieces of the pairs which are nearest the ends of the switch-board are
connected by wires with the secondary wire of the induction coil of a telephone
transmitter and with a telephone receiver both of which instruments are located in
the central office. The primary wire of the induction-coil of the telephone trans-
mitter is connected by a wire with a battery.

page_text: On the switch-board are metal bars arranged in pairs close together and secured
at the ends in such manner as to be insulated from each other. The spaces between
the pairs of bars are such that the plugs may be inserted between them; to cause the
bars to hug the plugs tightly when the latter are inserted between them, the spaces
between the bars of each pair are preferably somewhat narrower than the plugs, so
that when the plugs are inserted the bars will be slightly spread apart.
The circuit extends from the central office to the several subscribers without
going through the earth at all. If any of the plugs are withdrawn from their
contact pieces the latter make contact with each other and continue the circuit to
the next plug.
Communication is established between two subscribers by a private or special
circuit no part of which passes or is continued through the earth. There are pairs
of bars and one bar of each pair of bars is connected by a wire to one end of the
coils of electro-magnets comprised, in an electro-magnetic annunciator, the other
end of the said coils being connected with a battery and the ground by a wire.
The armature of the annunciator is pivoted to its support and normally raised from
the electro-magnets by a spring. It carries beyond the pivot a hook which
normally engages with the top of a plate that is hinged in place at the bottom and
has a tendency to drop forward.
When the subscribers who were conversing no longer desire to remain in
communication either pushes his spring switch down on its contact pieces where-
upon a circuit is established from the ground wire along a wire to one bar, thence
along a wire to the electro' magnetic annunciator, and thence along a wire to the
ground. Thereupon the armature is attracted by the electro-magnets, the hook is
disengaged from the plate and the latter drops forward and exhibits a number
indicative of the pair of bars with which the annunciator is connected. The
attendant in the central office then removes the plugs of these subscribers wires
from the bars and replaces them in the holes. I may, if desirable, employ in lieu
of the above described switch a switch which will be operated by the act of
putting away or hanging up a receiver.
Preferably I employ, in connection with the cased flexible extensions of the
wires, weights attached to pulleys which travel upon the said flexible extensions.
These weights are advantageous because they keep the same taut and prevent
them from becoming entangled.
i
As all the subscribers wires are included in the main circuit save while they are
connected to establish communication between them and other subscribers, it is
obvious that when any subscriber lifts his receiver off its switch bar and places it
to his ear preparatory to conversing with the attendant at the central office he can
hear any order given to the attendant by another subscriber and can defer
beginning conversation with the attendant until that order is finished. Thus,
much confusion in the giving of orders to the attendant may be avoided. When
two subscribers are put in communication in the manner before explained they
have a private circuit and nothing they may then say will be heard by other
subscribers.
On the switch-boards, in addition to the pairs of bars which are employed to
establish communication between two subscribers which are connected with the
same central office are other pairs of similar bars which are reserved for use in
establishing communication between the central offices.
These pairs of bars of each central office are permanently connected by pairs of
wires with the corresponding pairs of bars in the other central office.
In each central office there is a telephone transmitter and a receiver and these
instruments are connected together in any suitable manner by wires. At each
central office an attendant is especially assigned to these instruments and is kept
constantly listening at the receivers.
I

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
23rd November 1882.
"
WILLIAM ROBERT LAKE of the firm of Haseltine, Lake, and Co, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN TELEPHONIC APPARATUS
A communication to me from abroad by Charles Edward Chinnock, of Brooklyn
New York, United States of America.
This Invention relates to telephonic apparatus and comprises the combination in
a telephone system, of a central office, a complete metallic circuit extending
between the central office and the places of business or residences of subscribers,
means in the central office whereby the subscribers may indicate to an attendant
there that they desire to be put in communication with others, and means whereby
portions of the said metallic circuit which extends between these subscribers and
the central office may be removed from the circuit aforesaid, the said circuit may
be closed at the place of removal, and the subscribers thus cut out of the circuit
may be put into communication.
It also comprises the combination in a telephone system, of a central office, a
complete metallic circuit extending to the central office and to the places of
business or residences of subscribers, means in the central office whereby the
subscribers may indicate to an attendant there, that they desire to be put in
communication with others, and means whereby portions of the said metallic
circuit which extend between these subscribers and the central office may be
removed from the circuit aforesaid, the said circuit may be closed at the place of
removal and the portions thus removed from the circuit may be united to form a
private complete metallic circuit affording communication between the subscribers
to whom the portions of the circuit so removed and united belong.
It also comprises the combination, with telephone instruments in a central office
and at subscribers places of business or residences, of a complete metallic circuit
comprising pairs of wires extending between the central office and the several
subscribers' places of business or residences, means whereby any of the said pairs
of wires may be removed from the circuit, and means whereby, on the removal of
any of the said pairs of wires, the circuit will be closed at the place of their
removal. Preferably the means for closing the circuit will operate automatically on
the removal of the said pairs of wires
It also comprises the combination with telephone instruments in a central office
and at subscribers' places of business or residences, of a complete metallic circuit
comprising pairs of wires extending between the central office and subscribers'
places of business or residences, means whereby any of the said pairs of wires may
be removed from the circuit, and connected electrically with another pair of the
said wires, and means for closing the said circuit, at the points whence the said
pairs of wires were removed from it.
In the accompanying drawing
Figure 1 is a view of a telephonic apparatus embodying the said invention: and
Figure 2 is a diagram illustrative thereof.
Similar letters of reference designate corresponding parts in both figures.
I have drawn lines around all the devices which are located in the several
subscribers' places of business or residences and marked the said lines with the
word "subscriber." Likewise I have drawn lines around all the devices which are
arranged in the central offices and marked these lines with the words "Central
office No. 1" and Central office No. 2"
"
A, A, designate a number of telephone transmitters which are severally located
at subscribers' houses or places of business. These transmitters may be of any
approved kind.
The ends of the primary wire of the induction coil of each transmitter are
connected by a wire B with a battery C and two contact pieces a b. From one

page_text: end of the secondary wire of the induction coil a wire B' extends to a telephone
receiver D. A wire B2 extends from this receiver to the contact piece c of a
switch E. Froin an opposite contact piece d a wire B³ leads to one end of the
wire of the electro-magnet of an electro-magnetic call bell F arranged on the box
of the telephone transmitter. A wire B4 leads from the other end of the electro-
magnet of this call-bell to a wire B³ which extends from the other end of the
secondary wire of the induction coil to one of the central offices. The switch E
consists of a metallic bar which is suspended by a metallic spring E¹ at the upper
end and is provided at the lower end with a hook on which the telephonic
receiver D may be hung. To the switch bar E is attached a metallic cross-bar E²
having affixed to it, at one end, a metallic block E3 which however, is insulated
from it by a piece of insulating material e. A wire B6 extends from the spring E¹
to the central office
When the telephone receiver is hung on the hook of the switch-bar E, the latter
is drawn down so that its cross bar E² breaks contact with the contact piece c and
makes contact with the contact piece d, and the block E³, breaks contact with the
contact pieces a b The electric circuit then extends along the wire Be to the
spring E¹, thence along the switch-bar E, to its cross-bar E³, thence to the contact
piece d, thence along the wire B³, to the electro-magnet of the call-bell F, and
thence along the wire B, back to the central office. The call bell F is then in
circuit and the telephone transmitter A, and receiver D, are out of circuit. When
however the telephone receiver is taken off the hook of the switch bar E the latter
under the influence of the spring E¹, rises so that its cross-bar breaks contact with
the contact piece d and makes contact with the contact piece o, and the block E³,
makes contact with the contact pieces a, b. The circuit then extends along the
wire B6, to the spring E¹, thence to the bar E thence to the cross-bar E³ thence to
the contact point e thence along the wire B2 to the receiver D, thence along the
wire B¹, thence through the secondary wire of the induction coil, and thence along
the wire B5, back to the central office. The block E³, at the same time by connecting
the contact pieces a, b, completes the circuit through the primary wire of the
induction coil. The call-bell F, is then out of circuit and the telephone trans-
mitter A, and receiver D, are in circuit. From the wires B5, B6, adjacent to the
telephone transmitter and receiver, branch wires 65 66, extend to contact pieces g.
A spring switch G, connected with a ground wire H, is arranged adjacent to these
contact pieces and may be pressed against them by the subscriber to establish
communication between the wires B5, B6, and the ground wire H for a purpose
which I shall hereafter explain.
The wires B5, B6, are provided at the central offices with flexible extensions
which are together enclosed in an insulating casing of any suitable kind, and are
connected with plugs I. The plugs I. severally consist of two metallic terminal
plates ho, ho, affixed to opposite sides of a piece of insulating material 7; and the
said plates are electrically connected with the flexible extensions of the wires B5, B6.
Except when subscribers are put in communication with one another the plugs I
are inserted in holes j, in a switch-board J. These holes j, are furnished with pairs
of metal contact pieces kk, which, when the plugs are inserted in the holes, make
electrical contact with their plates h h but which, when the plugs are withdrawn,
spring together, and make electrical contact with one another. The contact pieces k
of each pair of contact pieces is connected by a wire k² with the contact piece k¹ of
the adjacent pair of contact pieces. The outer contact pieces k k¹, of the pairs
which are nearest the ends of the switch board are connected by wires K, K', with
the secondary wire of the induction coil of a telephone transmitter L, and with a
telephone receiver M, both of which instruments are located in the central office
The primary wire of the induction coil of the telephone transmitter L, is connected
by a wire K³, with a battery K³.
The
On the switch-board J, are metal bars l, l arranged in pairs close together and
secured at the ends in such a manner as to be insulated from each other.
spaces between the pairs of bars are such that the plugs I, may be inserted between

page_text: them, To cause the bars to clasp the plugs tightly when the latter are inserted
between them, the spaces between the bars of each pair are preferably somewhat
narrower than the plugs, so that when the plugs are inserted the bars will be moved
slightly away from each other,
The circuit extends along the wire K, to the first contact piece k, thence to the
plate 6 of the contiguous plug I, thence along the subscribers wire B6, which is
connected to that plug, thence back along the corresponding wire B5, to the plate h³, of
the said plug and from this-plate h³, to the contiguous contact piece k¹. From this
contact piece k³, the circuit extends along the wire which connects the said
contact piece with the contact piece k of the next pair of contact pieces, Thence
it extends along the plate h6, of the plug I, which fits between the said pair of
contact pieces, to the wire B6, which is connected with the said plate, then back
along the wire B³, to the plate h5 of the said plug and thence to the contact piece k¹
against which the said plate bears, In the same manner it extends to the
remaining pairs of contact pieces k, k¹, plugs I, and wires B6, B5, The contact
piece k, of the last pair of contact pieces is connected to the wire K', Thus it will
be seen that the circuit extends from the central office to the several subscribers
without going through the earth at all. If any of the plugs I, are withdrawn from
their contact pieces k¹ the latter make contact with each other and continue the
circuit to the next plug.
An attendant in each central office has, to constantly keep his receiver M, to his
ear, Any subscriber desiring to communicate with another subscriber who is
connected with the same central office takes down his telephone receiver and applies
it to his ear, thereby also switching his call bell out of circuit and his telephone
transmitter in circuit, He then tells the attendant in the central office what
subscriber he desires to converse with. The attendant then attracts the attention
of the latter by operating his call-bell and puts the two subscribers into com-
munication with each other by withdrawing the plugs I, from the holes j, in the
switch board and inserting them between a pair of bars l. 1. Communication is
thus established between two subscribers by a private or special circuit, no part of
which passes or is continued through the earth.
The bar of each pair of bars is connected by a wire n to one end of the coils
of electro magnets p comprised in an electro magnetic annunciator N the other end
of the said coils being connected with a battery and the ground by a wire o. The
armature q of the annunciator is pivoted to its support and normally raised from
the electro-magnets by a spring r. It carries, beyond the pivot, a hook 8 which
normally engages with the top of a plate t that is hinged in place at the bottom
and has a tendency to drop forward.
When the subscribers who were conversing no longer desire to remain in com-
munication either pushes his spring switch G, down on its contact pieces g where-
upon a circuit is established from the ground wire H along either wire B5 or B6 to
the bar thence along the wire n to the electro-magnetic annunciator N, and
thence along the wire o to the ground. Thereupon the armature q is attracted by
the electro-magnets, the hook s is disengaged from the plate t, and the latter drops
forward and exhibits a number indicative of the pair of bars l. 1, with which the
annunciator is connected. The attendant in the central office then removes the
plugs I, of these subscribers wires from the bars l. l', and replaces them in the
boles j.
In order that the said improvements may be more clearly understood I will
briefly recapitulate the primary features, referring to the diagram, Figure 2.
A designates the subscribers' telephone transmitters,' B5, B6, represent wires
extending therefrom to the central office; K K¹ are wires leading to the attendants'
telephone instruments at the central office. It will be seen that a complete metallic
circuit is obtained with but two wires extending between the central office and
each subscriber. All earth currents are, therefore, totally eliminated and much of
the induction ordinarily experienced is obviated.
3.
The dotted lines xx, indicate the connection which is made between two

page_text: subscribers when their plugs I, are inserted between a pair of bars 10. It will be
seen that in this way a complete metallic circuit is formed between two subscriber's
by means of their same two wires. The same good results are due to this complete
metallic circuit as to the main circuit which extends to the central office. The
dotted lines z, z, indicate the continuation of the main circuit by the contact
pieces k, l, at the place whence the two subscribers who were put into
communication with each other were withdrawn from the main circuit
"
In brief it may be said that a single continuous metallic circuit extends from
the central office to and from each of the subscribers. The wires leading to the
several subscribers may be regarded as bights or loops in the main circuit.
I do not confine myself to the use of both the branch wires 66 66, as either can
be made to suffice, but I prefer to use both, as then the plugs I, can be inserted
between the pairs of bars 1, 1, without regard to which of their plates ho, ho, makes
contact with the bar 1, so as to make it possible to operate the annunciator N.
I may if desirable employ in lieu of the switch G a switch which will be operated
by the act of putting away or hanging up a receiver.
Preferably I employ in connection with the cases flexible extensions of the
wires B5, B6, and weights W attach to pulleys which travel on the said flexible
extensions. These weights are advantageous because they keep the same taut and
prevent them from becoming entangled.
As all the subscribers wires are included in the main circuit except while they
are connected to establish communication between one subscriber and another it is
obvious that when any subscriber lifts his receiver off its switch-bar and places it
to his ear preparatory to conversing with the attendant at the central office he can
hear any order given to the attendant by another subscriber and can defer
beginning conversation with the attendant until that order is finished. Thus
much confusion in the giving of orders to the-attendant may be avoided. When
two subscribers are put in communication in the manner above explained they
have a private circuit and nothing they may then say will be heard by other
subscribers.
On the switch-board J, in addition to the pairs of bars 1, 1, which are employed
to establish communication between two subscribers which are connected with the
same central office are other pairs of similar bars 12 13, which are reserved for use
in establishing communication between the central offices.
The pairs of bars 12 13, of each central office are permanently connected by pairs
of wires P. P', with the corresponding pairs of bars in the other central office.
In each central office there is a telephone transmitter L', and a receiver M¹ and
these instruments are connected together in any suitable manner by wires O. 0¹,
At each central office an attendant is especially assigned to these instruments and
is kept constantly listening at the receivers.
When one of the subscribers, say for instance subscriber No 1 of central office
No 2 desires to communicate with one of the subscribers, say for instance sub-
scriber No 2 of central office No 1, the attendant listening at the receiver M', in
the central office first named notifies the attendant at the receiver M³, in the
other central office and thereupon the plugs I, of the wires B5, B6, of these
subscribers are inserted in the corresponding pairs of bars in the two central
offices. Thus a complete metallic circuit is formed between the two subscribers.
Having thus fully described the said invention as communicated to me by my
foreign correspondent and the manner of performing the same I wish it
understood that I claim :—
First. In a telephone system, the combination of a central office, a complete
metallic circuit extending between the central office and the places of business or
residences of subscribers, means in the central office whereby the subscribers may
indicate to an attendant there, that they desire to be put in communication with
others, and means whereby portions of the said metallic circuit which extend
between these subscribers and the central office may be removed from the
circuit aforesaid, the said circuit may be closed at the place of removal and the

page_text: subscribers thus cut out of the circuit may be put into communication, substantially
as specified.
Second. In a telephone system, the combination of a central office, a complete
metallic circuit extending to the central office and to the places of business or
residences of subscribers, means in the central office whereby the subscribers may
indicate to the attendant there, that they desire to be put in communication with
others, and means whereby portions of the said metallic circuit which extend
between these subscribers and the central office may be removed from the circuit
aforesaid, the said circuit may be closed at the place of removal and the portions
thus removed from the circuit may be united together to form a private complete
metallic circuit affording communication between the subscribers to whom the
portions of the circuit so removed and united belong, substantially as specified.
Third. The combination, with telephone instruments in a central office and at
subscribers places of business or residences, of a complete metallic circuit comprising
pairs of wires extending between the central office and the several subscribers places
of business or residences, means whereby any of the said pairs of wires. may be
removed from the circuit, and means whereby, on the removal of any of the said
pairs of wires, the circuit will be automatically or otherwise closed at the place of
their removal, substantially as specified.
Fourth. The combination, with telephone instruments in a central office and at
subscribers places of business or residences, of a complete metallic circuit comprising
pairs of wires extending between the central office and the subscriber's places of
business or residences, plugs I, provided with metallic plates connected with the
pairs of wires and insulated from each other, and the contact pieces k, k¹, substantially
as specified
Fifth. The combination, with telephone instruments in a central office and at
subscribers' places of business or residences, of a complete metallic circuit comprising
pairs of wires extending between the central office and subscribers places of business
or residences, means whereby any of the said pairs of wires may be removed from the
circuit, and connected electrically with another pair of the said wires, and means
for closing the said circuit at the points whence the said pairs of wires were
removed from it, substantially as specified.
Sixth. The combination, with telephone instruments in a central office and at
subscribers places of business or residences, of a complete metallic circuit comprising
pairs of wires extending between the central office and subscribers places of
business or residences, the plugs I, having metallic plates connected to the pairs of
wires but insulated from each other, the contact pieces k, k', and the pairs of bars l, l¹,
substantially as specified,
Seventh. The combination, with telephone instruments in a central office and
at subscribers places of business or residences, of a complete metallic circuit com-
prising pairs of wires extending between the central office and subscribers places of
business or residences, the plugs I, having metallic plates connected to the pairs of
wires but insulated from each other, the contact pieces k, k¹, the pairs of bars 1, l',
and the annunciators N, substantially as specified.
In witness whereof I the said William Robert Lake, have hereunto set my
hand and seal this Twenty third day of November in the year of Our Lord
one thousand eight hundred and eighty two..