Improvements in Electric Telephone Switches and Systems.
Year: 1891

page_text: Date of Application, 7th Aug., 1891
Complete Specification Left, 4th May, 1892-Accepted, 4th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Electric Telephone Switches and Systems.
I, THOMAS BEAVAN SLOPER, of 14 and 15 Brittox, Devizes in the County of
Wilts, House Furnisher, do hereby declare the nature of my invention to be as
follows:-
This relates to electric telephone switches and the system of working them the
arrangement being such that any two lines of the whole system may be connected
as required and the talking can be effected through the wires of the instruments of
both stations; in carrying the. invention into effect I prefer to proceed as
follows:-
I provide a preferably circular plate of wood, vulcanite or other suitable material
bearing upon it the numbers or denominating symbols of the various circuits, the
nu.nber in the series of the instrument itself and preferably a separate reply
symbol. In the centre of this plate I have a rotary piece preferably in the form of
a disc with a projecting contact point on the back or inner side of the plate the
point being adapted when required to be revolved and make contact with other
contact plates which are respectively in connection with the wires appertaining to
the other stations of the system. The hook upon which the ordinary telephone
receiver may be hung is pivotted in the plate and may be in the form of a three-
arned lever, one of the arms being the hook, another one caused by a spring to
make contact with an insulated contact plate connected with the telephone
appertaining to the instrument in question, or when the weight of the telephone
receiver upon the hook overcomes the spring to make contact with another insulated
contact plate connected with the bell appertaining to the same instrument.
The
third arm is adapted to move the disc longitudinally upon its axis so that its contact
point will be in the proper plane to make contact with any one of the contact plates
of the respective line wires of the system, when the receiver is off the hook. By
means of the same arm or of a separate spring when the telephone receiver is upon
the hook the disc is so moved that its contact point is clear of all the other contact
plates but so soon as the weight of the receiver is removed the disc moves forward
projecting the point into the plane of the other plates. These contact plates are
preferably arranged radially upon the back of the circular plate which may be
recessed for the purpose a projecting ring being preferably left to prevent these
points, which may with advantage be in the form of springs, from getting into the
plane occupied by the disc and its point when the telephone receiver is upon the
hook. In addition to the radial contact plates above described there is preferably
another point carried in yet another plane with which the disc can be brought into
contact when pushed in for the purpose; this contact is in direct connection with
the battery appertaining to the station and through it the battery current can be
carried to any of the wires of the system in order to ring the bell. Each of the
various contact plates of any one instrument of the system is connected with the
hook arm of that instrument of the system to which its number appertains. Thus
plate No. 5 has a wire lirect to the hook arm of the instrument of No. 5 station
and so on.
The operation of this instrument will be well understood. The receiver being
upon the hook the hook arm is in connection with the bell plate so that a current
coming to the hook arm from any one of the other instruments of the system would
ring the bell; upon the receiver being lifted off the hook the bell is cut out of the
circuit and connection is made between the distant station and the home station
telephone, the return being through the earth wire. It will therefore be seen that
in this instrument if both stations speaking are pointing to each other's numbers the

page_text: talking may be carried on either through the contact plate and the disc contact
points of the two instruments and the connecting wires, in which case the currents
would be divided between that circuit and the home wire and earth, or if one of the
contact points, say at the distant station, was placed out of connection with the
contact plate the talking would only be through the distant wire. and earth.
secret
As it is sometimes desirable to confine the communications between two particular
instruments of the system and cut out all the rest I employ what I call a
circuit which may be effected as follows:-In connection with each station I have
a switching device consisting of two spring contacts, one connected with the earth
wire and the other with the main wires appertaining to all the other instruments of
the system. In any suitable manner, conveniently by employing the hook arm
which may be employed ordinarily to carry the second receiver of the telephone
instrument the contacts above mentioned may be broken say by the reverse end of
the hook arm engaging with one of the contacts breaking its contact with the earth
wire and moving it into contact with the other contact point which at the same time
is disconnected from its contact with the main instrument to which it appertains.
By this arrangement-the currents flow normally through the usual course but if a
secret connection is desired or if other stations are interrupting, the two stations
talking point to each other's numbers, then upon the removal of the second receiver
or when by other means the normal connections are broken and the abnormal
connection is made the two instruments concerned are cut out of the earth or return
circuit and conversation can be carried on only between those two instruments and
no signals of any kind can be made between them and the other instruments, until
the two in communication have re-hung their receivers. It will be observed that
when the secret switch is in use, the currents flow by the line of one station and
return by that of the other.
In applying this system of working to apparatus of the ordinary construction the
line wire instead of being dependent upon the contact arm is carried direct to the
hook lever, the "secret circuit" being introduced if needed.
Where only one receiver is used I may employ an extra lever which is put out
of use by hanging the receiver upon its hook, but is brought into use only by the
special act of the operator; this extra lever is so arranged as to effect the makes
and breaks required for the introduction of the "secret circuit."
Any line outside the system may be connected to any line in the system through.
holes in the front of, the switch case. In this case a plug or jack in connection
with the outside line would be inserted in the hole required.
Dated this. 7th August 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electric Telephone Switches and Systems.
1; THOMAS BEAVAN SLOPER, of 14 and 15 Brittox, Devizes in the County of
Wilts, House Furnisher, 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 :-
This invention relates to electric telephonic switches and the system known as the
inter-communication system, of working them, the arrangement being such that any
two lines of the whole system, which may include any desired number of instru-
ments may be connected directly with each other without an intermediate station
and if desired the talking effected through the wires of the instruments of both
stations.
The invention will be best understood by reference to the accompanying
drawings in which

page_text: Figs. 1 and 2 are respectively a front and back elevation of one form of the
switch adjusted as when ready for ringing-up No. 6 station.
Fig. 3 is one half of a back elevation showing the switch as when it has received
a call and is being talked through.
Fig. 4 is a section taken on line 4-4 of Fig. 2.
Figs. 5 and 6 are sections taken on line 5-6 of Fig. 2, Fig. 5 showing the switch
as when adjusted for ringing-up No. 6 station, and Fig. 6 as when such ringing-up
is in operation.
Figs. 7 and 8 are similar half-back elevations of a switch constructed on the same
principle as that shown in Figs. 1 to 6 but in addition provided with a switch or
bridge for cutting off the earth or return wire altogether from the two com-
municating stations and connecting them in such a manner that the current between
the two stations pass by one wire and return by the other thus isolating the two
instruments being conversed through from all the others of the series, Fig. 7
representing the switch in its normal position & Fig. 8 as when it has been rung-up
and adjusted for private conversation with station No. 6 by the person at the
called-up station.
Figs. 9 and 10 are views showing the two different positions of the additional
switch or bridge for forming the "secret circuit."
Fig. 10 is a section drawn to a smaller scale than Figs. 1 to 10 showing the
switch arranged with the hook arm in the form of a three-armed lever.
Fig. 1 is a diagram showing an installation of six stations provided with the
switch shown in Figs. 1 to 6 and
Fig. 12 is a similar diagram showing an installation of six stations provided with
the switch shown in Figs. 7 to 10.
Like letters indicate like parts throughout the drawings.
Throughout this Specification and in the accompanying drawings each of the
switches shown in Figs. 1 to 10 is described and illustrated as adapted for an
installation of six instruments but it will readily be understood from the following
description that by increasing or decreasing the number of contacts the switch may
be constructed for an installation of a larger or smaller number of instruments.
Referring to Figs. 1 to 6, A is a preferably circular block or plate of wood,
vulcanite or other suitable material recessed at its back to receive the various
contact devices and perforated and preferably metal-bushed at its centre to admit
of the spindle B being moved longitudinally and rotarily therein. On the outer
end of the spindle B are secured a head or press-button B an index or pointer B2
and a crank handle B7 which may be formed in part with the pointer B and on the
outer face of the block A are depicted numbers A' or other denominating symbols
corresponding to the several stations in the installation less that of the instrument
itself which may advantageously be more boldly depicted as at A². The pointer B
may be turned by the handle B7 to any of the numbers A' as also to a plate bearing
the word "reply or other symbol A³ Fig. 1 to which it should though not
compulsorily be directed when the instrument is not in use.
21
CC2 C3 CC and C are six contact plates to five of which are fitted contact
springs each for convenience marked with a corresponding small letter e etc. these
when hereinafter collectively mentioned being referred to as the contact
springs &c., the index numerals of these large and small reference letters in this
description serve also to identify the various contacts with the different instruments
of the installation. Each of the six contact plates C' C² C³ C C & C as also
the contact plates D F and G are provided with binding screws e for connecting
the various conductors to them as hereinafter explained. B³ is a metal disc secured
by a screw B on a squared or equivalently shaped part of the spindle B and which
is provided with an arm or projection B adapted to make electrical contact with
the inner ends of the springs c or c² etc.; the arın or projection B instead of being
formed in part with the disc B³ may be integral with the spindle B. His a spring
which bears upon the head of screw B so as to tend always to press the spindle B.

page_text: outwards and the disc B³ against the contact I as shown in Fig. 4 and returns said
parts to said respective positions after having been pressed inwards as shown in
Fig. 6 by a person ringing-up another station and in which inner position the
contact between B³ and I is broken. The spring H does not act as an electrical
conductor; if desired a helical spring encircling the spindle B may be substituted
for the spring H.
J is the hook arm upon the outer or hooked end of which as ordinarily the
receiver is hung as shown in Figs. 1 and 2 and which is pivotted at J and which
a spring J attached thereto always tends to draw to the position shown in Fig. 3.
Fis a contact spring upon which the arm J bears when held down by the weight
of the receiver K, and G and I are two other contact springs the latter of which
is connected by wire L' with the contact I and both of which are normally, that is,
when the arm J is in its lowered position, out of contact with each other and with
the hook arm J as shown in Fig. 2 but which, when the receiver K is removed
and the spring J2 allowed to raise the arm J, are pressed into electrical contact
both with each other and with the arm J as shown in Fig. 3.
The contact plate C2 is electrically connected by a wire C and through the
pivot with the hook arm J, and the contact plate D which as hereinafter
explained is connected to the local battery, is provided with a metal blade D¹
which as shown in Fig. 5, is out of contact with the disc 133 when said disc is
pressed forward by the spring H but with which the disc B³ makes electrical
contact when it is pushed back by the operator for calling-up a distant station.
The inner end of each of the contact springs e¹ &c. is preferably. provided with a
rib or projection as shown clearly in Figs. 5 and 6 and the arm B³ is also
provided with a groove B for receiving this projection so that it may readily
be felt by the resistance to further rotation when the arm B³ is in proper contact
with any required contact spring but other equivalent means may be provided for
this purpose.
The switch shown in Figs. 7 to 10 differs from that before described only in the
addition of the isolating switch or bridge now to be described and in some of the
electrical connections which are altered to suit this addition.
In Figs. 7 and 8 M M¹ represent a bell-crank lever pivotted at M³ and is
constructed preferably of insulating material such as vulcanite and to the arm M'
of which is secured a metal plate M³. The arm M like the hook arm J projects
through a slot in the block A to the outside of said block and is so arranged that
after the receiver K has been removed froin off J and the lever arm M has been
raised by hand from the position shown in Fig. 7 to that shown in Fig. & the said
lever arm M will be moved to its original position (Fig. 7) whenever the receiver K
is again hung on arm J. NN are two contact springs the free ends of which are
normally in contact with two plates O O' respectively. The contact springs N N'
as shown clearly in Figs. 9 and 10 are bent so as to allow the metal-plate-carrying-
lever arm M to work beneath them and while in the position shown in Figs. 7 and 9
to be out of contact with them and allow them to rest in contact with the
plates OO, and so that when the lever M M is moved to the position shown in
Fig. 8 the arm M' will raise the springs N N' out of contact with plates O O¹ and
make electrical contact between them through the plate M³ which at that time
bears against the underside of both of the springs.
In this arrangement the pivot J' of arm instead of being directly connected
to the plate C as in the former example is indirectly connected to it by wire O*
leading from to O, contact spring N, and conductor 03 leading from N to C² the
circuit through these conductors being broken as soon as the spring N is raised off'
plate O. The plate O¹ is connected with a plate E by wire O and the contact
spring N is connected by a wire O with a plate P which like the other similar
plates before described is provided with a binding screw c.
In Fig. 10 the hook arm upon which the telephone receiver K may be hung is
pivotted in the plate A so as to project out through the front of it and is in the

page_text: form of a three-armed lever, the arm J having the hook formed upon it, the arm J³
being caused by the spring J2 to make contact with the contact plate or spring GI
connected with the telephone appertaining to the instrument in question, or, when
the weight of the telephone receiver K upon the hook overcomes the spring J the
arm Ja as shown in Fig. 10, makes contact with the contact plate or spring F
connected with the hell appertaining to the same instrument. The third arm L
(referred to by these two letters because it fulfils the functions of the before
described contacts I and L) is adapted to move the disc B³ longitudinally upon its
axis so that its contact projection 135 will be in the proper plane to make contact
with any one of the contact plates & &c. of the respective line wires of the system,
when the receiver K is off the hook. By means of the same arm I L or of the
spring H similar to that before described and shown in Figs. 2 to 8 when the
telephone receiver K is upon the hook, the disc B³ is so moved that its contact
projection B is clear of all the other contact plates or springs c' &c. but so soon
as the weight of the receiver K is removed, the disc B³ moves forward, projecting
the arm B into the plane of the plates or springs . In addition to the radial
contact plates or springs c' &c. there is also provided the metal blade D' with
which as in the before described examples, the disc B³ can be brought into contact
when pushed in for the purpose; this contact is in direct connection with the battery
appertaining to the station and through it the battery current can be carried to any
of the wires of the system in order to ring the bell at a distant station.
Referring now to Fig. 11, which diagrammatically represents an installation of
six telephone stations numbered from 1 to 6 and each provided with a switch
similar to that shown in Figs 1 to 6, it will be seen that all the contact springs c¹
except at station No. 1 where such spring is not necessary are connected together
by conductor P¹ and that this conductor is connected through plate C and wire C
with hook-arm pivot J of said No. 1 station. Similarly all the contact springs c
except at No. 2 station where it is not necessary are connected together by
conductor P which is connected through plate C2 with pivot as shown clearly
in Figs. 1 and 2 which represents this No. 2 switch. All the contact springs c³
except at No. 3 station where one is not necessary are connected together by
conductor P3 which is connected through plate C³ with pivot J of No. station,
and so on throughout the series of switches.
Each of the contact plates F is connected by a wire F with one terminal of
the coils of a call bell Q, Q, Q³, Q, Q, or Q the other terminal being connected
by a wire Q to earth. Each of the plates G is connected by wire R to one
terminal of the appropriate telephone R1, R2, R3, R*, R³ or R the other terminal
of which is connected through wire S to earth. Each of the blades D₁ is
connected by wire T to one pole of a local battery T'T' T³ T₁ T' or T the
other pole of which is connected to earth by a wire T.
The operation of the installation shown in Fig. 11 is as follows,
Supposing the operator at No. 1 station requires to call up No. 3 station he
first turns round the index B until it points to the number three (A') so as to
bring the arm B3 into contact with and then presses the button B so that the
disc B³ bears against the blade D¹. The current from battery T₁ now passes
through the blade D' disc B³ and contact spring of No. station along wire P³
to No. 3 station where it passes through plate C³, pivot J, hook-arm J spring F',
plate F, wire F to bell Q3 the circuit being completed through wires Q of No. 3
station, earth and T' of No. 1 station. In this manner the bell Q³ will be sounded
and all the operator at the called up station (No. 3) has to do is to take the
receiver K off hook-arm J at that station and preferably place the index B² at
"reply as shown with regard to the arm B in Fig. 3 when he can talk through
the telephone as usual. This operation at No. 3 station by allowing the hook-
arm J to be raised by its spring J2 out of contact with spring F breaks the
circuit through the bell Q³ The operator at No. station by removing the
pressure of his hand from the knob at that station allows the spindle B to be
returned by its spring H to its normal position when the contact with blade D'
::

page_text: and consequent circuit through the battery T will be broken; he then removes
his receiver K from the hook-arm J at his (the No. 1) station so that by the
ascent of the hook-arm J out of contact with spring F the circuit through the
bell Q is broken and the telephone circuit between the two instruments R' and R³
is completed in the following manner,
One terminal of each of the telephones R', R³ is connected to earth by one of
the wires S and assuming the current through the switches to pass from station
No. 1 to station No. 3 it will leave the telephone R by way of the appropriate
wire R pass to switch of No. 1 station through plate G and the spring contacts G¹
and L which are then pressed together by hook-arm J, contact I disc B³ disc-
arm 135 contact and leave station No. 1 through the wire P³ which conducts the
current to the plate C3 of No. 3 station. The current then passes through wire C
to pivot and through hook-arm J, contact G plate G and wire R to the
telephone R³.
If when the operators at say the No. 1 and No. 3 stations are speaking the
arm B at No. 1 station be in contact with the spring e as before described and
the arm B at No. 3 station be in contact with spring d then the currents will
pass between the two instruments partly through the wire P and partly through
the wire P returning through earth, the hook arm J of No. 1 instrument being
then clectrically connected with No. 3 switch and the hook arm J of No. 3
connected with No. 1 switch.
With the last described system and because one terminal of each of the
telephones is connected to earth it is possible for the conversation between two
stations, say Nos. 1 and 3 as before, to be heard through the instrument of a third
station by the operator at that third station say No. 2 turning the arm B until
it makes contact through one of the springs in this example either e¹ or with
one of the wires P or P³ through which the telephonic currents pass. It is to
overcome this that I devised the system illustrated in Figs. 7, 8, 9, 10 and 12 and
which I call the "secret circuit system" and by which any two stations of the
series may be completely cut out of communication with the others.
In this system as shown in Fig. 12 the bell-circuit is completed and broken in
precisely the same way as in the arrangement shown in Fig. 11. None of the
telephones R &c. are however directly connected with earth.
66
22
Supposing now that the operators at stations Nos. 1 and 4 desire to employ the
secret circuit system and they have placed themselves in communication as
before described, by lifting their respective receivers off the hook arms J and
turning the arms B into contact with the springs c and c¹ respectively both of
which in this instance must be so adjusted, they each then raise the lever arm M
at the respective stations. The telephone currents then pass between the two
stations No. 1 and No. 4 as follows, assuming that they first pass from the
telephone R through the wire R. They pass at No. 1 station through plate G
and through the spring contacts G' and L which are pressed together by hook
arm J, through wire L³, contact 1, disc and disc-arm B³ B5, contact c¹ and leave
No. 1 station and pass to No. 4 station by wire P. At this station No. 4 the
currents pass through plate C wire 0³, spring N, plate M³, spring N¹, wire 0%,
plate P from which the currents pass to the telephone R through wire S. The
currents then in the reverse manner pass from the telephone R₁ to telephone R¹
by way of the following of the No. 4 station connections viz.,-plate G, spring
contacts G and L, wire L', contact I, disc and disc-arm B³ B³, contact c¹. The
currents then pass from No. 4 station to No. 1 station by the wire P¹ and at
No. 1 station they pass to the telephone R' through the following of the
No. 1 station connections viz.,-plate C, wire 0³, spring N, plate M³, spring N¹,
wire O, plate P, and wire S.
If the lever arms M of any two stations in communication are not raised as last
described then the "secret circuit system" is not brought into operation and the
conversation carried on between those two stations may as in the arrangement
shown in Fig. 11 and after similar adjustment of the contacts be overheard at

page_text: another station. In Fig. 12, stations Nos. 2 and 6 are shown connected in this
manner, without employing the secret circuit system "with the two stations
connected in this manner and the arms 15 at each station being respectively in
contact with springs and ² and assuming the current to How first from
telephone R through wire R at that station it will take either of two courses at
station No. 2 in one of which it will pass through the following connections of said
station No. 2 in the order in which they are named ria-plate G, contacts Gland L,
wire L', contact I, disc and disc-arm B3 B contact. The current thus leaving
station No. 2 will be conducted to station No. 6 through wire P and will then
pass through the following connections of station No. 6 in the order in which they
are named viz.,-plate C, wire O³, spring N, plate O wire 0%; pivot J', hook
arm J and contact G, plate G, wire R, telephone R, wire S, plate P, wire ()³,
spring N, plate O¹, wire O, plate E, wire U to earth, through which the current
passes and returns to telephone R2 through the following connections of
station No. 2 viz.,-wire U, plate E, wire O, plate O', contact spring N¹, wire 05,
plate P and wire S. The other alternative open to the passage of the currents
between No. 2 station to No. 6 is first from telephone R² through wire R and
through the following of the No. 2 station's connections riz.,-plate G, contact G',
hook arm J, pivot J', wire O², plate O, contact spring N. wire 3. plate C², wire P
which conducts the currents to contact plate C2 at No. 6 station. At this station
the currents thus conducted pass through the following of the No. 6 station
connections vispring contact ², disc-arm and disc B B, contact I, wire L,
contacts L and G₁, plate G, wire R, telephone R", wire S, plate P', wire 0³,
spring contact N1, plate O', wire O, plate E and wire U to earth with which the
telephone R2 is also connected as before explained.
The before described apparatus instead of being constructed with an adjustable
arm B for making contact with the distant line termini which however is the
preferred arrangement, may be provided with an adjustable plug for this purpose,
and in other respects the invention may be modified without departing from the
spirit of the invention, for example, if desired the contacts F¹ Gand L and the
hook arm J may be mounted on a block or frame independent of the block A
upon which are mounted the switch contacts c &c. and parts co-operating
therewith. For the sake of facilitating the understanding of the invention no
mention is herein previously made to the use of microphones in conjunction with the
before described apparatus, when such however are used an extra contact as usual
is required for closing the circuit when the receiver is off the hook.
In cases where no microphone is used one battery may if desired be arranged
to ring all the bells in the system.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is,-
1. An intercommunication telephonic system in which each switch is insulated
from its home line, its telephone its bell and the earth or return wire when the
receiver is on its hook, so as to avoid the necessity of replacing the switch after a
conversation substantially as described.
2. In a telephonic installation the combination with a switch board at each
station of a contact permanently connected with the telephone a movable hook
arm and another contact which may be connected through the switch with any
of the distant lines each of the contacts being out of contact with the other and
with the home line when the receiver is on the hook arm and each of which when
the receiver is removed from the hook arm makes contact with the other and with
the line wire substantially as described.
·
3. In a telephonic switch-board the combination with a hook-arm J of a
contact such as G' permanently connected with the telephone and contact such as L
which may be connected through the switch with any of the distant lines both of
the contacts being out of contact with each other and with the home line when

page_text: the receiver is on the hook arm and both of which when the receiver is removed
from the hook arm make contact with each other and with the line wire
substantially as described and illustrated in the accompanying drawings.
4. In an intercommunication telephonic system the combination with a look arm
such as connected with the line wire of a contact such as L connected to the
switch used for connecting with different lines and another contact such as G
connected to the telephone so arranged that both contacts are out of contact with
the hook and with each other when the receiver is on its hook and both when
the receiver is removed from the hook arm make contact with each other and with
the hook arm J substantially as described.
•
5. In a telephonic switch board apparatus the combination with a disc such
as B3 or spindle such as B having an arm such as B³ of a number of spring
contacts such as c &c. surrounding it and constituting the termini of the distant
lines a home-line contact such as I with which the disc B³ is normally in contact
and a battery contact such as D¹ with which the disc B³ is normally out of
contact substantially as described and illustrated in the accompanying drawings.
6. In an electrical switch for connecting the home telephone line with either
of a number of other lines a spindle such as B having a projection such as 135 which
when revolved makes contact with either one of a series of springs in connection
with the distant lines, so arranged that it may be temporarily pressed out of its
normal plane and that in so doing it will break contact with the home line and
telephone and will make contact with the battery thus sending a current to the
distant line substantially as described.
7. In an intercommunication telephonic installation in which several stations are
connected directly with each other the complete cutting out or insulating of two
communicating stations from the circuit of the other stations by cutting out the
earth or return wire and allowing the current to pass and return respectively by
the two wires connecting the two stations substantially as described.
8. The combination with a telephonic switch board of two spring contacts such
as N N corresponding plates 00' and adjustable lever such as M M M³ so
arranged that by operating said lever at each of two communicating stations the
earth or return circuit is altogether cut out the current then passing and returning
respectively by the two wires connecting the two stations substantially as
described and illustrated in the accompanying drawings.
9. The combination and arrangement of parts constituting the complete
telephonic switch board apparatus substantially as described and illustrated in
Figures 1 to 6 of the accompanying drawings.
10. The combination and arrangement of parts constituting the complete
telephonic switch-board apparatus substantially as described and illustrated in
Figures 7 to 10 of the accompanying drawings.
11. The combination and arrangement of parts constituting the complete
telephonic system substantially as described and illustrated in Figure 11 of the
accompanying drawings.
12. The combination and arrangement of parts constituting the complete
telephonic system substantially as described and illustrated in Figure 12 of the
accompanying drawings.
Dated this 20th dex of Anul 1000