Year: 1886

page_text: I CORNELIUS HERZ, of 1 Boulevard St-Denis, Paris, France, Doctor do hereby
declare the nature of this invention to be as follows:-
The object of this invention is to improve and simplify house telephone installa-
tions and other telephonic appliances.
It has a three-fold purpose, viz:-
1st To replace the ordinary call buttons as well as the apparatus called "telephone
buttons" by a new apparatus which I call the micro-telephone button and which
acts at once as a call button, a telephone receiver, and a microphonic transmitter.
2nd To give direct telephonic communication from one: room to another without
the intermediation of a central office or exchange and without the aid of other
batteries than those used for the operation of the ordinary call buttons.
3rd To reduce the number of conducting wires to the strict minimum.
The micro telephone button is a telephone button with which I have combined a
microphonic transmitter, the telephone of the button serving as a receiver only.
A commutator automatically establishes all the necessary connections. The
apparatus which will be permanently or temporarily fixed against a wall, or on a
movable support, comprises the following essential parts:
A carbon diaphragm.
A carbon plate formed with holes in which freely rest rods, likewise of carbon
and furnished with small leaden weights.
An induction coil.
A commutator the action of which I will proceed to explain. It is formed
of a spring fixed at one end and carrying, at the other end a small rod, which
projects at the front part of the microphone. When the telephone button is in
place, that is to say, when it is in the position of rest, the commutator wakes com-
munication between a line wire (which for the sake of distinction I will call B) and
the wire (C) which goes to the bell, and this by the intermediation of the spring.
When the telephone button is lifted in order to speak the commutator comes against
plate to which one of the ends of the secondary winding of the induction coil
eads. The other end of this winding is connected by a wire which I will call n to
he telephone. Always following the same circuit, we come by another wire which
will call m to a line wire which I will call D. The commutator has then already
eparated the bell from the line circuit, substituting for it the secondary winding
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page_text: of the coil and the telephones, but at the same time, an insulated plate fixed to the
commutator has established communication between two springs one of which is
connected by a wire which I will call A to one of the poles of the battery, the
positive for example, while the other spring communicates with the carbon
diaphragm of the micro-telephone. The carbon plate is connected with one of the
ends of the primary winding: the other end of the same winding being attached by
a wire which I will call E to the negative pole of the battery; the primary circuit
is then closed. The wire m before entering into the winding of the telephone is
connected in the interior of the telephone button with the spring to which the call
button is fixed. The contact which serves to close the circuit when it is wished to
sound the bell is connected by a wire to a circular insulated contact, fixed to the
outer box of the telephone button.
The diaphragm of the microphone is held by a brass washer, also insulated and
connected in the interior of the microphone to the wire E. This arrangement
allows of dispensing with a wire between the fixed part and the movable part of
the micro-telephone button, because there is no need of sounding the bell when the
telephone has been removed in order to speak.
I also construct my apparatus in the following manner in order to save a line
wire and ensure good contacts :-
The button of the apparatus which contains also the telephone is attached to the
base of the apparatus, which holds the microphone, by means of bayonet joints, of
which the action is easily understood and need not be described. When the
apparatus is open for speaking the telephone button is removed from its seat in
order to be held to the ear.
When the button is on its seat any of the other stations can be called by means
of the call buttons and bell.
Suppose station No I calls station No II. The call button is pushed inwards and
presses a spring at station I against a screw contact thus breaking the previously
existing contact and putting the bell of station I out of circuit, while establishing
communication through the bell and station II as follows:-
From the screw contact by a wire (C) to the negative pole of the battery, the
positive pole of the battery is connected with a wire (B) which is attached to the
commutator at station II; from thence to a spring contact through the bell and to
other spring contacts and by a wire (A) establishing the return to the station I,
then by the spring which rests on the screw contact.
In taking off the telephone button the bell is put out of circuit by the movement
of the commutator which leaves its spring contact and makes contact with two
other spring contacts, thus closing the primary and secondary circuits.
The primary circuit is established as follows:-From the positive pole of the
battery to the wire B, to the commutator, to one of the spring contacts last referred
to, then through the bobbin, of which the second end is connected with the
diaphragm, from the diaphragm the circuit follows the carbon contacts to the
wire C which is connected with the negative pole of the battery.
The secondary circuit follows the other of the spring contacts, the commutator,
the wire B, to station II, then goes by the commutator at station II to a spring
contact, the bobbin, the receiver; and from thence to the wire A, returning to the
receiver at station I the bobbin at this station and a spring contact.
The wire connecting the telephone button with the base containing the micro-
phone, can either hang loosely between its two ends, or can be concealed in any
manner, for instance, by winding it into a box provided with a spring, like those
used for spring tape measures.
The ordinary telephonic apparatus consists of a number of independent distinctive
parts which are located near each other, but still at different points of the station;
each element of the apparatus preserves its independent individuality and all are
connected with each other by conductors and switches. These connections are
always more or less complex, and in the higher organised instruments, they become
quite confusing to such an extent so that very frequently the best electricians find

page_text: it very difficult to trace the circuits. Thus, when an apparatus is being mounted
at a station those having charge of the work are continually seen in search of the
proper connections: much time is thereby lost, and the cost of the installation is
proportionally increased. Another source of inconvenience in the ordinary tele-
phonic apparatus is found in the considerable size of the transmitter and in the fact
that the operator is compelled to assume a certain definitive position in relation to
the same; holding the receiver to his ear, he must turn his head toward and approach
closely to the transmitter. The attention of the operator which should be confined
to the conversation is in a great measure diverted toward the proper management
of the instruments, as is well known, and whenever the operator fails to properly
divide his attention, the conversation becomes a source of annoyance. By the
person with whom he is in conversation, he is constantly requested to speak louder
or lower, to retreat from or to approach to the transmitter more or less, and he is
obliged to make the same requests.
It is an object of my present invention to overcome in a great measure all these
difficulties, and to this end I have constructed an apparatus which comprises, in
one individual structure, a transmitter, a receiver, and a push button, and I have
succeeded in embodying all these parts in a form similar to the ordinary magneto-
receiver, all of which will more fully appear from the following description. The
instruments are the same at each station and I shall therefore confine myself to the
description of the instrument at station I.
The exterior of the apparatus is very similar to the ordinary magneto-receiver.
It consists essentially of an elongated shell which is contracted at one end, and
flaring at the other end; of a cylinder which is connected to the flaring end of the
shell by a screw ring, and of a mouthpiece. The shell contains the inductorium or
induction coil, a push button or press key, a switch button or key, an elastic switch
arm and the microphone. The diaphragm of the microphone is applied to the open
flaring end of the shell by screws or otherwise. Behind the diaphragm which is
made of conducting material, and parallel thereto, is a bar of insulating material
fixed to the walls of the shell, and in the centre of said bar is located a small tube
of carbon or other microphonic substance. A carbon pin passes loosely through this
tube and is at one end in contact with the diaphragm; this contact is maintained.
and regulated by a spring having a button at one end which presses on the pin
within the tube. The spring is secured to the rear of the bar by means of two
screws, and by tightening or loosening one of these screws, the contact is adjusted.
Other suitable means of adjustment may however be employed.
To a flange on the cylinder there is secured a magnet having the form of a flat
rectangular fraine which is axially polarised and to which polar extensions are
secured to the ends of which the cores and magnet coils are applied. The diaphragm
of the receiver is held in place by the mouthpiece. The shell has a series of per-
forations immediately behind the bar, and the screw ring has similar perforations
which communicate with the space between the microphone diaphragm and the
flange of the cylinder. These perforations are the sound openings for the micro-
phone and through them the sounds emitted by the operator are conducted to the
diaphragm, while the instrument is held to the ear, as will be more fully explained
further on.
The push button when depressed establishes contact between a spring and a fixed
contact piece. The elastic switch arm before mentioned is fixed at one end and is
operated by the switch button, projecting through the side of the shell, like the
push button; the said switch arm has secured upon one side, but insulated there-
from, a metal plate which is adapted to make contact with fixed contact pieces;
on the same side of the switch arm there is also a contact piece, while on the other
side there is a contact piece on the path of the end of the switch arm. The
tendency of the elastic switch arm is to make contact with the last named contact
piece, but when the switch button is depressed the said contact is broken while
contact of the arm with the contact piece on the other side is established and at
the same time the metal plate makes contact with the fixed contact pieces.

page_text: The circuit connections within the instrument need not be specifically described,
but they will be referred to in the description of the operation.
When there are only two stations there are four line wires, which I will call
A, B, C, D; between C and D is placed the battery, and from the line wires
branches, which I will call A, B, C, D¹, run to the telephone. These wires are in
practice bunched together and are distinguished from each other by different colors.
A signalling bell connects on one side with branch wire D¹ and on the other side
by a wire which I will call E, with the contact piece of the telephone.
The operation of this apparatus is as follows:-If station I desires to establish
communication, the operator grasps the instrument so as to press on the push
button without touching the switch button, contact between the spring and the
fixed contact piece is thereby established, which closes the bell circuit for station II
viz From the positive pole of the battery over line D to and through wire D¹ of
station II, through the bell of that station; wire E; telephone contact; switch
arm, wire B¹ to line B back to station I; at this station the circuit proceeds over
wire B¹ to the fixed contact and spring of the push button, wire C¹ and line wire C,
to the negative pole of the battery.
The operator at station II being thus notified that station I desires to speak,
will grasp the instrument so as to depress the push button without, however,
touching the switch button. This closes the bell circuit for station I, which circuit
need not be here described since it is in all respects like that of the bell circuit of
station II. Both operators now relieve the pressure upon the push button, and
each of them depresses the switch button, whereby the microphone circuits for both
stations, and also the common receiver circuits, are closed. For station I the
microphone circuit is:-From the positive pole of the battery over line wire D,
branch D¹ to the diaphragm of the microphone, through the microphone, and from
tube of the same by a wire to one of the fixed contacts over the insulated plate to
the other fixed contact and by a wire to and through the primary circuit of the
inductorium, from where it issues and runs to the fixed end of the spring of the
push button then over wire C¹ and line wire C, back to the negative pole of
the battery. The microphone circuit for station II is quite similar and need not be
described.
The common receiver circuit is:-From the secondary circuit of the inductorium
of station I by a wire to and through the magnet coils to the fixed contact of the
push button, over branch B₁ and line wire B to station II, where it enters at B¹,
which at that station connects by a wire with the switch arm: from the switch
arm the circuit is over the contact, and by a wire to and through the secondary
circuit of the inductorium and by a wire, to and through the contact of the push
button from this contact the circuit continues over branch A¹ and line wire A. back
to station I where it enters by. branch A¹ running by a wire to the switch arm,
and thence back to the secondary circuit of the inductorium.
During conversation the instrument is constantly held against the ears, and the
words are uttered in the ordinary tone of conversation without directing them to
any particular point; the sound waves emanating from the mouth of the speaker
expand in concentric spheres, and, entering through the holes, operate the micro-
phone in the ordinary manner.
In instruments which I have constructed, I bave found that conversation can be
carried on with great comfort without at any time removing the same from the ear.
I can modify at will the arrangement of the microtelephone buttons: thus I can
. place the induction coil in the box of the bell or on the annunciator board, if there
is one, or I may place it near the central battery. I can also replace my microphone
by any other known microphone. I can vary the relative dispositions of the parts
that constitute the microtelephone buttons, and, lastly, I can change my commu-
tator as well as the contact between the fixed part and the movable part of the
apparatus.
When it is desired to make several stations communicate with each other by
employing for the telephones a circuit absolutely. independent of the battery and

page_text: by making use of an annunciator board, when there is one, I arrange my apparatus
so that the microphone is submitted to the action of only a part of the battery.
The number of wires necessitated by this arrangement is: n (n-1) + 3, where n
is the number of stations. When microphones are employed which, like mine, can
support the whole current from the battery, I adopt an arrangement which requires
a number of wires represented by the formula n (n-1) + 2.
In these arrange-
ments I employ a commutator to establish communication with the station that it
is wished to call or with the station from which a call comes, and the number of
which is given by the annunciator board.
B
When it is wished to do without an annunciator board by arranging, for
example, for the purpose of knowing from where a call comes, that the first station
shall always ring once, the second twice, and so on, the installation can be con-
siderably simplified, and the number of wires reduced to n + 2. I will show with
what facility a telephonic and microphonic installation can be made in this way
from an existing electric bell installation.
I replace first all the bell buttons by a microtelephonic button, a bell and a
commutator, to as many directions as there are stations less one. I connect wires,
which I will call A and C, to the-bell; a wire D to the axis of the commutator
and a wire E to one of the existing wires that lead to the battery.
I connect the other existing wire to the same binding screw of the bell on the
wire A. I then take a cable containing as many wires as there are stations and
make it pass through all the rooms that should communicate with each other.
I number the rooms and the wires of the cable. I attach the wire which bears the
number of the room, where I happen to be, to the wire of the microtelephone
button; finally. I connect the free binding screws of the commutator to the other
wires of the cable. I also combine the call bell, or gong, as the case may be, with
the combined transmitter, receiver and switch, as described, thus forming one
device of the four organs.
To this end I sometimes make the external case of the
telephone button the call bell, the hammer being actuated by the call signal
currents in a manner well understood In other dispositions I place the bell
elsewhere in the apparatus, the novelty consisting in the embodiment of the call
bell or gong with the transmitter, receiver and switch as one instrument.
I can, if I so desire, suppress the bell and produce the call by the vibration of
the telephone membrane either by means of a special induction coil or by using the
coil of the microphone.
A modification of the microtelephone button, to which I give the name of
automatic microphone station, allows of the employment of an annunciator board
while reducing the number of wires to n ("21) + 2. There is still a commutator,
but this time, I replace the single button of the microtelephone and the commutator,
for establishing communication with the station that it is wished to call or with
the station from which a call comes, by as many buttons as there are lines.
The lines lead to the annunciator board and traverse a small electro magnet
whose plate or armature closes the circuit of the bell when a current passes through
the electro-magnet. The object of this is to prevent the bells of all the stations
being put in action when any one station calls another.
I can replace the electro-magnet by a solenoid and an iron core or by any other
electrical or mechanical arrangement that will effect the same purpose.
Again, instead of employing as many electro magnets as there are lines, I can
have only one and pass over it all the windings corresponding to the different lines.
When a call button is depressed the circuit of its own bell is opened and the
number of its annunciator board which corresponds with the station called is
short circuited in order that it may not itself cause numbers to appear at its own
station. The commutator acts as before, but the call button should be kept
depressed all the time the conversation lasts.
In an automatic microphone station arranged in the manner I have just de-
scribed a contact serves to withdraw the presented numbers. An abutment of the

page_text: telephone carrier hook is a spring fixed at one side only, which does not touch the
contact under the unaided action of the weight of the telephone, but it is sufficient
to press lightly when hanging up the telephone after a conversation to effect the
momentary closing of the circuit of the recall coils and withdraw the presented
numbers.
In an arrangement which I employ to automatically keep the call buttons
depressed while the telephonic communication lasts and to return them when the
conversation is finished, the commutator controls by means of a rod a series of bent
levers movable around a common axis. When the telephone is hung up the levers
permit of calling freely but when the telephone is unhooked the levers shift in a
manner to prevent depression of the lifted buttons or the rise of those that are
depressed. It is thus easily understood that it suffices to depress a button with
the one hand and to unhook the telephone with the other to establish the corre-
sponding telephonic communication. The communication is self-maintained until
the telephone is hung up after the conversation is finished. This being done the
numbers that have appeared are withdrawn, the depressed button is raised and
the instrument is thus automatically put at the position of rest.
I can modify the form and the arrangement of my microphone stations. Thus
for example, I can place the bell in the station itself or outside. I can also replace
the electric devices for withdrawing the presented numbers by a mechanical device
actuated by the commutator.

page_text: and Systems and Telephonic Appliances.
I CORNELIUS HERZ, of 1 Boulevard St Denis, Paris, France, Doctor do
hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:
The object of this invention is to improve and simplify house telephone
installations and other telephonic appliances.
It has a three fold purpose,-viz :-
1st To replace the ordinary call buttons as well as the apparatus called "telephone
buttons" by a new apparatus which I call the micro-telephone button and which
acts at once as a call button, a telephone receiver, and a microphonic transmitter.
2nd To give direct telephonic communication from one room to another without
the intermediation of a central office or exchange and without the aid of other
batteries than those used for the operation of the ordinary call buttons.
3rd To reduce the number of conducting wires to the strict minimum.
The micro telephone button-see Figures 1, 2, 3 and 4-is a telephone button
with which I have combined a microphonic transmitter, the telephone of the button
serving as a receiver only. A commutator T automatically establishes all the
necessary connections. The apparatus which will be permanently or temporarily
fixed against a wall, or on a movable support, comprises the following essential
|parts:
A carbon diaphragm V.
A carbon plate W formed with holes in which freely rest rods S, likewise of
carbon and furnished with small leaden weights P.
An induction coil I.
A cominutator T the action of which I will proceed to explain. It is formed of
a spring fixed at one end and carrying at the other end a small rod t, which
projects at the front part of the microphone. When the telephone button is in
place, that is to say, when it is in the position of rest, the commutator makes
communication between the line wire B and the wire C which goes to the bell,
and this by the intermediation of the spring. When the telephone button is lifted
in order to speak the commutator comes against a plate U to which one of the
ends of the secondary winding of the induction coil leads. The other end of this
winding is connected by a wire n to the telephone. Always following the same
circuit, we come by the wire m to the line wire D. The commutator T'has then
already separated the bell from the line circuit, substituting for it the secondary
winding of the coil and the telephones, but at the same time, an insulated plate
fixed to the commutator T has established communication between the two
aprings g and c, one of which, g, is connected by the wire A to one of the poles of
the battery, the positive for example, while the other spring c communicates with '
the carbon diaphragm V. The carbon plate W is connected with one of the ends
of the primary winding, the other end of the same winding being attached by '
the wire E to the negative pole of the battery; the primary circuit is then closed..

page_text: The wire m before entering into the winding of the telephone is connected in the
interior of the telephone button with the spring to which the call button is fixed.
The contact b which serves to close the circuit when it is wished to sound the bell
is connected by a wire to a circular insulated contact o, fixed to the outer box of
the telephone button.
The diaphragm V of the microphone is held by a brass washer o¹ also insulated
and connected in the interior of the microphone to the wire E. This arrangement
allows of dispensing with a wire between the fixed part and the movable part of
the micro-telephone button, because there is no need of sounding the bell when the
telephone has been removed in order to speak.
I also construct my apparatus in the following manner in order to save a line
wire and ensure good contacts :—
Figure 5 is a perspective view shewing the apparatus in the position of
waiting.
The button of the apparatus which contains also the telephone is attached to
the base of the apparatus, which holds the microphone by means of bayonet joints,
as shown, of which the action is easily understood and need not be described.
Figure 6 shows the apparatus open for speaking the telephone button being
removed from its seat in order to be held to the ear. Figure 7 is a back view of
the apparatus. Figure 8 shows the connections.
!
When the button is on its seat, the apparatus being as shown in Figure 5, any
of the other stations can be called by means of the call buttons and bell.
In Figure 8, station N° I calls station No II. The call button (Figure 5) is
pushed inwards and presses the spring b (Figure 8) at station I against the screw
contact thus breaking contact with r and putting the bell of station I out of
circuit, while establishing communication through the bell and station II as
follows:-
From the contact by the wire C to the negative pole of of the battery; the
positive pole of the battery is connected with the wire B which is attached to the
commutator T at station II; from thence to the spring contact.1 through the bell
and to the spring contact r, from thence to the spring band by the wire A, estab-
lishing the return to the station I, then by the spring 6 which rests on the
contact v.
In taking off the telephone button the bell is put out of circuit by the move-
ment of the commutator which leaves the spring contact 1 and makes contact
with the spring contacts 2 and 3, thus closing the primary and secondary circuits.
The primary circuit is established as follows:-From the positive pole of the
battery to the wire B, to the commutator T, to the spring contact 3, then through
the bobbin, of which the second end is connected with the diaphragm; from the
diaphragm the circuit follows the carbon contacts to the wire C which is connected
with the negative pole of the battery.
The secondary circuit follows the spring contact 2, the commutator T, the wire B,
to station II, then goes by the commutator T at station II to the spring contact 2,
the bobbin II, the receiver R; and from thence to the wire A, returning to the
receiver R at station I by the bobbin II at this station and the spring contact 2.
It is understood that for the arrangement, as represented in Figures 5 and 6, the
wire connecting the telephone button with the base containing the microphone can
either hang loosely between its two ends, or can be concealed in any manner, for
instance, by winding it into a box provided with a spring, like those used for spring
tape measures.
The ordinary telephonic apparatus consists of a number of independent distinctive
parts which are located near each other, but still at different points of the station;
each element of the apparatus preserves its independent individuality and all are
connected with each other by conductors and switches. These connections are
always more or less complex, and in the higher organised instruments, they become
quite confusing, to such an extent so that very frequently the best electricians find
it very difficult to trace the circuits. Thus, when an apparatus is being mounted

page_text: at a station those having charge of the work are continually seen in search of the
proper connections; much time is thereby lost, and the cost of the installation is
proportionally increased. Another source of inconvenience in the ordinary tele-
phonic apparatus is found in the considerable size of the transmitter and in the fact
that the operator is compelled to assume a certain definite position in relation to the
same; holding the receiver to his ear, he must turn his head toward and approach
closely to the transmitter. The attention of the operator, which should be confined
to the conversation, is in a great measure diverted toward the proper management
of the instruments, as is well known, and whenever the operator fails to properly
divide his attention, the conversation becomes a source of annoyance.
He is
constantly requested, by the person with whom he is in conversation, to speak
louder or lower, to retreat from or to approach to the transmitter more or less, and
he is obliged to make the same requests.
It is an object of my present invention to overcome, in a great measure, all
these difficulties, and to this end I have constructed an apparatus which comprises
in one individual structure, a transmitter, a receiver, and a push button, and I
have succeeded in embodying all these parts in a form similar to the ordinary
magneto-receiver, all of which will more fully appear from the following description.
The instruments are the same at each station and I shall therefore confine myself
to the description of the instrument at station I.
The exterior of the apparatus is very similar to the ordinary magneto-receiver.
It consists essentially of an elongated shell F (Figure 9) which is contracted at
one end, and flaring at the other end; of a cylinder G which is connected to the
flaring end of the shell by a screw-ring K, and of a mouth-piece H. The shell F
contains the inductorium or induction coil, I, the push button or press key L, the
switch button or key M, an elastic switch arm T, and the microphone. The
diaphragm N of the microphone is applied to the open flaring end of the shell by
screws or otherwise. Behind the diaphragm, which is made of conducting material,
and parallel thereto, is a bar O of insulating material fixed to the walls of the
shell, and in the centre of said bar is located a small tube a of carbon or other
microphonic substance. A carbon pin passes loosely through this tube a and is at
one end in contact with the diaphragm; this contact is maintained and regulated
by a spring c having a button 6 at one end which presses on the pin within the
tube a, as shown. The spring c is secured to the rear of the bar O by means of
two screws, and by tightening or loosening one of these screws, the contact is
adjusted. Other suitable means of adjustment may, however, be employed.
To a flange on the cylinder G there is secured a magnet P, having the form of a
flat rectangular frame, which is axially polarised and to which polar extensions g
are secured, to the ends of which the cores and magnet coils R, R are applied. The
diaphragm S of the receiver is held in place by the mouth-piece H. The shell F
has a series of perforations V immediately behind the bar O, and the ring K has
similar perforations W, which communicate with the space between the diaphragm N
and the flange of the cylinder G. These perforations are the sound openings for
the microphone and through them the sounds emitted by the operator are
conducted to the diaphragm N, while the instrument is held to the ear, as will
be more fully explained further on.
The push button L when depressed establishes contact between the spring d and
the fixed contact piece e The elastic switch arm T is fixed at one end, and is
operated by the switch button M projecting through the side of the shell, like the
push button L; the said switch arm has secured upon one side, but insulated
therefrom, a metal plate f which is adapted to make fixed contact with fixed
contact pieces gland h; on the same side of the switch arm there is also a contact
piece i, while on the other side there is a contact piece j on the path of the end of
the switch arm. The tendency of the elastic switch arm is to make contact with j,
but when the button M is depressed the said contact is broken while contact of
the arm with is established and at the same time the plate f makes contact with
g¹ and h.
3

page_text: The circuit connections within the instrument are very clearly illustrated, and
need not be specifically described, but they will be referred to in the description of
the operation. When there are only two stations connected as shown in Figure 9,
there are four line wires, A, B, C, D; between C and D is placed the battery, and
from the line wires branches A¹ B¹ C¹ D¹, run to the telephone. These wires are
in practice bunched together and are distinguished from each other by different
colors. A signalling bell connects on one side with branch wire D¹ and on the
other side by a wire E, with the contact piece ; of the telephone. The line
wires A, B are crossed in the drawing for convenience of illustration.
The operation of this apparatus is as follows:-If station I desires to establish
communication, the operator grasps the instrument so as to press on the button L
without touching the switch button M; contact between d and e is thereby estab-
lished, which closes the bell circuit for station II, viz: From the positive pole of
the battery over line D to and through wire D¹ of station II, through the bell of
that station; wire E; contact j; switch arm T; wires and B' to line B back to
station I;
at this station the circuit proceeds over wire B¹ to contact e, spring d,
wire C¹ and line wire C, to the negative pole of the battery.
The operator at station II being thus notified that station I desires to speak,
will grasp the instrument so as to depress the button L without, however, touching
the switch button M. This closes the bell circuit for station I, which circuit need
not be here described since it is in all respects like that of the bell circuit of
station II. Both operators now relieve the pressure upon the push button and
each of them depresses the switch button, whereby the microphone circuits for
both stations, and also the common receiver circuits are closed. For station I the
microphone circuit is-From the positive pole of the battery over line wire D,
branch D to the diaphragm N of the microphone, through the microphone, and
from tube a of the same by a wire m to contact g¹, over the insulated plate / to
contact, and by wire 1 to and through the primary circuit of the induction coil,
from where it issues at 1' and runs to the fixed end of spring d, then over wire C¹
and line wire C, back to the negative pole of the battery. The microphone circuit
for station II is quite similar and need not be described.
The cominon receiver circuit is:-From the secondary circuit of the induction
coil of station I by wire 2 to and through the magnet coils R, R to the fixed
contact e, over branch B¹ and line wire B to station II, where it enters at B¹, which at
that station connects by the wire with the switch arm T; from T the circuit is
over contact i, and by wire 21 to and through the secondary circuit of the induction
coil and by wire 2, to and through the contact e; from this contact the circuit
continues over branch A¹ and line wire A back to station I where it enters by
branch A running by wire to the switch arm T, and thence by contact i and
wire 2 back to the secondary circuit of the induction coil.
During conversation the instrument is constantly held against the cars, and the
words are uttered in the ordinary tone of conversation without directing them to
any particular point; the sound waves emanating from the mouth of the speaker
expand in concentric spheres, and entering through the holes V and W, operáte the
microphone in the ordinary manner.
In instruments which I have constructed, and of which Figure 9 is a slightly
enlarged illustration, I have found that conversation can be carried on with great
comfort without at any time removing the same from the ear. Figure 10 is a
diagrammatic view of two micro-telephone buttons joined together. I can modify
at will the arrangement of the micro-telephone buttons just described; thus I can
place the induction coil in the box of the bell or on the annunciator board, if there
is one, or I may place it near the central battery. I can also substitute any other
known microphone for my microphone. I can vary the relative dispositions of
the parts that constitute the microtelephone buttons, and, lastly I can change my
commutator T as well as the contact between the fixed part and the movable part,
of the apparatus.

page_text: Figures 11 and 12 show how I would arrange my apparatus when it is desired
to make several stations communicate with each other by employing for the
telephones a circuit absolutely independent of the battery and by making use of
an annunciator board, when there is one.
In the case of Figure 11 the microphone is submitted to the action of only a
part of the battery current. The number of wires necessitated by this arrange-
ment is n (n-1)+3, where n is the number of stations. When microphones are
employed which, like mine, can support the whole current from the battery, I
adopt the arrangement, shown in Figure 12, which requires a number of wires
represented by the formula n (n-1)+2.
Figure 13 represents the whole of the connections of the micro-telephone button,
of the bell of the battery and of the annunciator board. The arrangement of the
annunciator board can however be modified.
The object of the commutator H, which is seen in Figures 11, 12 and 13, is to
establish communication with the station that it is wished to call or with the
station from which a call comes, and the number of which is given by the
annunciator board.
When it is wished to do without an annunciator board by arranging for example,
for the purpose of knowing from where a call comes, that the first station shall
always ring once, the second twice, and so on, the installation can be considerably
simplified, and the number of wires reduced to n+2. Figure 14 represents this
arrangement sufficiently clearly to render it unnecessary to give further details.
I will only show with what facility a telephonic and microphonic installation can
be made in this way from an existing electric bell installation.
I replace first all the bell buttons by a microtelephone button, a bell and a commu-
tator to as many directions as there are stations less one. I connect the wires A
and C to the bell; wire D to the axis of the commutator and wire E to one of the
existing wires that lead to the battery.
I connect the other existing wire to the same binding screw of the bell on the
wire A. I then take a cable containing as many wires as there are stations and
make it pass through all the rooms that should communicate with each other.
I number the rooms and the wires of the cable. I attach the wire which bears the
number of the room, where I happen to be, to the wire B of the microtelephone
button; finally I connect the free binding screws of the commutator to the other
wires of the cable. I also combine the call bell, or gong as the case may be, with
the combined transmitter, receiver and switch, as described, thus forming one
device of the four organs.
To this end I sometimes make the external case of the
telephone button the call bell, the hammer being actuated by the call signal
currents, in a manner well understood. In other dispositions I place the bell else-
where in the apparatus, the novelty consisting in the embodiment of the call bell
or gong with the transmitter, receiver and switch as one instrument.
I can,
if I so desire, suppress the bell and produce the call by the vibration of
the telephone membrane either by means of a special induction coil or by using
the coil of the microphone.
A modification of the microtelephone button to which I give the name of
automatic microphone station allows of the employment of an annunciator board
while reducing the number of wires to n ("² = 1) + 2.
The arrangement of the circuits in this case is shown diagrammatically in
Figure 15. There is still the commutator T, but this time, I replace the single
button of the microtelephone and the commutator H by as many buttons as there
are lines.
The lines lead to the annunciator board and traverse a small electro-magnet
whose plate or armature closes the circuit of the bell when a current passes
through the electro-magnet. The object of this is to prevent the bells of all the
stations being put in action when any one station calls another..

page_text: · I can replace the electro-magnet by a solenoid and an iron core or by any other
electrical or mechanical arrangement that will effect the same purpose.
Again, instead of employing as many electro-magnets as there are lines, I can
have only one and pass over it all the windings corresponding to the different
lines.
When a call button is depressed the circuit of its own bell is opened and the
number of its annunciator board, which corresponds with the station called, is
short-circuited in order that it may not itself cause numbers to appear at its own
station. The commutator T acts as before, but the call button should be kept
depressed all the time the conversation lasts.
Figure 16 is a diagram representing an automatic microphone station arranged
in the manner I have just described. The two binding screws marked M are those
to which the wires of the microphone lead. The contact Y which is shown in
detail in Figure 17 serves to withdraw the presented numbers. The abutment e
of the telephone carrier hook is a spring fixed at one side only, which does not
touch the contact Y under the unaided action of the weight of the telephone, but
it is sufficient to press lightly when hanging up the telephone after a conversation;
to effect the momentary closing of the circuit of the recall coils and withdraw the
presented numbers.
Figures 18 and 19 represent an arrangement which I employ to automatically
keep the call buttons depressed while the telephonic communication lasts and to
return them when the conversation is finished. The commutator controls, by
means of a rod B, a series of bent levers l, movable around a common axis o.
When the telephone is hung up as in Figure 18 the levers permit of calling
freely, but when the telephone is unhooked as in Figure 19 the levers rise so as to
lock all the buttons in the positions they then respectively occupy whether
depressed or not. It is thus easily understood that it suffices to depress a button
with the one hand and to unhook the telephone with the other to establish the
corresponding telephonic communication. The communication is self maintained
until the telephone is hung up after the conversation is finished. This being done
the numbers that have appeared are withdrawn, the depressed button is raised and
the instrument is thus automatically put at the position of rest.
I can modify the form and the arrangement of my microphone stations. Thus,
for example, I can place the bell in the station itself or outside. I can also use in
place of the electric devices for withdrawing the presented numbers a mechanical
device actuated by the commutator.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim, in respect of electric bell and house telephone apparatus and systems and
telephonic appliances, is :-
1. The combination of a microphonic transmitter with a receiving telephone
and a call button, forming what I have termed the micro-telephone button, as
set forth.
2. The annular contact of the fixed part and movable part of my micro-telephone
button, as set forth.
3. The combination of a microphonic transmitter with a receiving telephone, a
call button, and a commutator or switch, in a single fixed or movable device,
substantially as described.
4. In a telephone the combination of a microphone transmitter with a receiving
telephone, a call button, a call bell or other alarum, and a commutator or switch, in
a single fixed or movable device, substantially as described.
5. The arrangement of my automatic microphone stations, and especially the
employment of the telephone carrier commutator to hold the call buttons during
the conversations and to withdraw the numbers that have appeared at the indicator
boards, as set forth..

page_text: 6. The arrangement of the systems hereinbefore described and especially those
which allow of the employment of n+2 wires with my microtelephone buttons and
of n("") +2 wires with my automatic microphone stations.
7. Constructing or fitting commutators with two press keys or push buttons
to open or close the primary and secondary circuits separately, substantially as
described with reference to Figure 9.
8. Arranging the telephone button so that parts, such as b and r, Figure 8, can
be put in connection, whereby the bell of the station which calls can be excluded
and the use of a line wire saved.
9. A portable telephone apparatus comprising a microphone-magneto receiver,
and push button, substantially as described.
10. A portable telephone apparatus consisting of a magneto-receiver, a micro-
phonic transmitter arranged behind the same, a signalling push button, and suitable
connections, substantially as described.
11. In a portable telephonic station apparatus, the combination of a microphone
with a magneto receiver covering the same, and sound openings between the
receiver and microphone, communicating with the latter, substantially as described.
12. A hand telephone consisting of a case containing a microphone receiver, push
button, and switch, in combination with an induction coil, also located within the
case, substantially as described.
13. In a hand telephone the combination of a microphone and a magneto-
receiver with a push button or press-key for signalling projecting through the
handle of the instrument, and another push button or key operating a switch
within the case for closing and opening the microphone and line circuit, sub-
stantially as described.