IMPROVEMENTS IN TELEPHONES
Year: 1883

page_text: LETTERS PATENT to Charles Almon Jackson of Laurence in the County of
Essex and State Massachusetts United States of America for an Invention of
"IMPROVEMENTS IN TELEPHONES
"
3
COMPLETE SPECIFICATION filed by the said Charles Almon Jackson at the
Office of the Commissioners of Patents on the 19th November 1883.
CHARLES ALMON JACKSON of Lawrence, in the County of Essex, and State of
Massachusetts, United States of America, "IMPROVEMENTS IN TELEPHONES,"
The objects of this invention are first to avoid the waste of time now consumed
in waiting for an opportunity to call up any given subscriber on a telephonic
circuit or series of circuits and to do away with the central office, so called, now
extensively in use-secondly in means for enabling a subscriber upon one line to
communicate directly with a subscriber upon another line, for instance in a different
city and thirdly to enable two or more subscribers to communicate with different
subscribers from the same instrument at the same time.
In my present system I discard the central office, as before stated, and in lieu of
the ordinary circuits having their termini massed in such office, I employ a number
of closed circuits sufficient to enable any subscriber under ordinary circumstances
to find some one of them unoccupied, or to greatly multiply the chances of his
thus finding one, and I run the entire series of these wires through each subscriber's
instrument. Moreove I furnish to each subscriber an adjustable or movable
switch board carrying a wire in which is included a receiver and transmitter and
whose ends are connected with conductors secured to such switch board, these
conductors being so arranged as to close the circuit through the wire when the line
is broken, thereby enabling any subscriber to put himself in communication with
and operate over any circuit wire.
'
By this means any subscriber is enabled to ascertain at once directly from his
own instrument which of the circuit wires are in use, and communicate directly
with any other subscriber on any of said wires without recourse to a central office.
The conductors of the switch board operate, when intercepting a key placed in

page_text: each one of the circuit wires, to break the circuit of such wire and reestablish such
circuit through the wire carried by the switch board; the wire thus becomes for
the time a part of the circuit, and as it carries a receiver and transmitter
conversation may be had directly with any circuit not occupied.
The drawings accompanying this specification represent in Figure 1. a plan, and
in Figure 2. a cross section of a device embodying my improvements. Figure 3. is
an underside view of the movable switch board. Figure 4. is a plan of the
registering device-Figure 5. is a view of its dial. Figure 6. is a diagram showing
the operation of several instruments.
In said drawings A represents 'a tablet upon the top of which are placed a
number of telegraphic keys B B B etc. arranged in a straight row and parallel to
each other, the number of these keys being determined by the extent of business
carried on in any particular locality or localities. In the present instance I have
shown eight keys, each of which is composed of two plate springs a b of conducting
metal, the free end of one (for instance a) resting upon the free end of the other (b)
as shown in Figures 1 and 2. CCC etc. represent a series of telephonic circuit
wires, each wire being intercepted by a key B, as shown. When the two portions a b
of a key are separated, the circuit through the wire C is broken and vice versa.
D represents a switch board disposed above the range of keys B B etc. and supported
upon horizontal parallel rods E E in manner to slide upon the latter transversely
of the said range of keys, said switch board preferably carrying a pointer F to
enable it to be readily adjusted in position over any given key.
The switch board is composed of hard rubber or other material adapted to
insulate it from its supporting rods E E. G.in the drawings represents a wire the
two ends c d of which pass down through the switch board, the end c being
connected to a contact point or conductor fin the form of a knob secured to and
depending from the underside of said switch board. The end d of the wire G
connects with a contact point d¹ extending upward through the switch board.
Included in the wire G are a receiver H and transmitter I. e in the drawings
represents a second contact point in the form of a knob carried by and depending
from the underside of the switch board D, this knob being connected by a
conducting metal plate j with a second contact point k extending through the
switch board.
The two knobs e fare so arranged with respect to the keys B B etc., that is one
below the other, as when passing over any one of said keys to separate the two
parts of the latter and break the circuit through the wire C direct, and reestablish
such circuit through the wire G, thereby putting the receiver and transmitter
contained in such wire in communication through such wire C. As shown in the
accompanying drawings the knob f extends below the knob e and operates with
and serves to depress the lower leaf b of any key, while the knob e operates with
the upper leaf a of any key.
When the switch board is moved over any one key the knob e bears upon and
establishes communication with the upper portion a of said key, while the knob f
bears upon and establishes communication with the lower portion b of such key,
at the same time separating the two leaves by pushing down 6 and thereby breaking
the circuit through such key. P represents a vibratory arm of conducting metal
pivoted at its base to the contact point d'. The free end of the arm P is adapted
to be swung into contact with either of the points e or f. J in the drawings
represents a wire one end of which is connected with a third contact point or
conductor K secured to the top of the switch board, the opposite end of this wire
carrying for convenience in use a plug L adapted to be inserted in a socket i in the
top of either screw post M which is connected with one end of each key B.
By this simple device, when a subscriber desires to communicate with another.
he has only to place the arm in contact with the point k and move the switch
from one key to another, thereby for the time closing the circuit with some one
line C, at the same time placing the receiver H to his ear, and is thus enabled to
ascertain which wire C is unoccupied. When an unoccupied wire C is found the

page_text: subscriber allows the switch board to remain over such key and can then commu-
nicate directly with any subscriber on said line through the transmitter I. As
soon as the knobs e f pass by and release the key, the latter automatically closes
and the circuit is reestablished direct through the wire C.
I have described my invention as applied to a telephonic system which
necessitates the discarding of a central office and the employment of additional
circuit wires. The principle of my invention however is applicable to the present
system in which a central office is used, as it will be only necessary in this latter
system to mass the wires together at each subscriber's instrument in the manner
shown in the drawings in which the wires C C etc. may be the wires of the present
system.
Suppose for illustration the wire marked B¹ to connect the instrument with the
city of London and the wire marked B¹¹ to connect it with Liverpool, and a
subscriber in the former city desires to communicate with one in the latter city.
The arm P is swung into contact with the point K and the switch board moved
along until its pointer marks the said key B, and the plug L is inserted in the
screw post of the key B'. The electric circuit is now closed through the key B¹,
plug L, wire J, contact point K, arm P contact point d, wire G, contact point f,
and key B. Conversation may now be had by means of the receiver H and
transmitter I.
To enable two or more subscribers to communicate with different subscribers at
the same time from the same instrument, I employ two or more switch boards as
shown in the drawings.
In connection with the above improvements in the operation of telegraphic
circuits, I employ an instrument carrying a dial which contains the numbers of all
the subscribers on a given circuit or number of circuits, and an index hand or
pointer operating therewith capable of being set to any of said numbers, and
when so set of opening communication with the subscriber designated by said
number.
The construction of this device is as follows-A³ represents a tablet upon the
top of which is arranged an ordinary electric key A' and four screw cups B³ C³
DS ES. The bridge of the key is shown at F3 and the contact point of such bridge
at G. A spring Js is secured at its base to the top of the tablet, the free end of
this spring bearing upon the periphery of a toothed wheel K³ of conducting metal
secured to a horizontal shaft L³ supported in bearings in upright standards N³ N¹
erected upon a base plate 03 secured to the tablet, such standards being properly
bound together and like the base plate being composed of conducting metal.
Ps represents a scape wheel fixed to the shaft L³ alongside the wheel K³, and with
the periphery of this wheel operates an escapement Q3 formed upon one end of a
horizontal escapement lever R³, such lever being pivoted to a post S³ erected upon
the base plate O³ and its tail being lifted by a spring Ts connected with a post U³
erected above the lever.
V³ represents a horizontal armature secured to the tail of the lever R³, such
armature operating with a pair of electro magnets W³ X3 supported upon the base
plate Os. The battery for operating this instrument is shown at Ys. Its negative
pole connects with the screw cup B and this cup connects with the key A* by a
wire Z³. The contact point G³ of the key bridge F connects. by a wire a with
magnets W³ X³. The magnet X³ is connected by a wire b with the spring Js
before named. The standard N³ is connected by a wire c' with the screw cup C³
and the screw post Cs connects with the positive pole of the battery. Beneath the
free end of the key A* is a contact point H³ which connects by a wire d with the
screw post E and this post E³ connects with the screw post D³ by a wire e² in
which is included an electric bell f³.
The screw post D³ connects by a wire g² with a spring h³ secured at its base to
the inside of the standard N and insulated from such standard by a washer i³.
The free end of the spring h² operates with a contact point or pin ja carried by a
circular disk k² of insulating material secured to and rotating with the shaft L

page_text: before named. An additional spring 13 is secured at its base to the standard N*,
this spring being situated on the side of the disk k opposite its mate h* and like
the latter operates with the contact point 2 of such, disk.
C in the drawings represents a dial plate secured to the outside of the
standard N' the front end of the shaft L³ extending through this dial plate and
carrying an index pointer or hand D₁ to read the scale F' of divisions upon the face
of the dial plate. This scale is an annular one extending about the plate near its
circumference, such scale consisting of a number of equidistant divisions each of
which is numbered and represents a different subscriber.
The dials of every
subscriber's instrument are alike and the hands of all the instruments point to the
same division upon the scale, but the contact point of the disk varies with each
subscriber and is so adjusted that when the hand of any instrument is set to any
given subscriber's number the contact point corresponding to his number is
embraced by the free ends of the springs h² and 7³.
The two circuits are as follows-one, when the key is raised and in contact with
the contact point G³, is from the negative pole of the battery to post B³, thence by
wire Z³ to key A thence to bridge F³ through contact point G³, from the bridge by
wire a to magnets W³ X3, from X3 by wire 62 to spring J³, from spring Ja through
scape wheel P³ to the shaft L³ of such wheel, thence to standard Ñ³ and from such
standard by wire c² to screw post C³ and from the latter to the positive pole of the
battery. When this circuit is closed the hand and disk are in constant rotation.
When the key is depressed into contact with the point H³ the above circuit is
broken and the hand stops, and the current then takes the following direction-from
the negative pole of the battery to post B³, thence by wire Z³ to key A', and
thence to bridge F³, as before-the current now goes from the key A' to contact
point H³, from thence by wire d² to screw post E³, from E3 by wire e² to screw
post Ds (thereby ringing the bell f³) from post D³ to spring h³, from this spring
by contact point j³ of disk k³ to spring 12, from this spring to standards N' N³
and from N3 by wire c³ to screw post C³, and from the latter to the positive pole
of the battery.
When the key A' is in its normal position in contact with the point G³ the
pointer is rotated as follows-it being observed that the free end of the spring Js
bears upon the point of but one of the teeth of the wheel K³-and the armature V³
being raised by its spring T-the battery being let on the armature V³ is attracted
and lowered and the escapement advances the scape wheel P³ and the shaft L³ a
distance corresponding to one tooth of such wheel, thereby carrying the tooth
which is in contact with the spring J³ past the latter and breaking the circuit-the
armature is thus released and is lifted by its spring, thereby advancing the scape
wheel one tooth and bringing into contact with the spring Js the tooth next
succeeding the one last in contact with such spring, which again closes the circuit
as before and lowers the armature a second time, and these movements are repeated
in rapid succession, thereby intermittently opening and closing the circuit and
rotating the scape wheel and shaft.
When it is desired to call a given subscriber the caller stops the pointer at the
number on the dial denoting the subscriber he desires to call by depressing the
key A. This reverses the current and carries it through the course second above
described, thereby ringing the bell of the instrument of the subscriber being
called.
The more fully to explain the operation of my system I have shown in Figure 6.
of the drawings a diagram in which I have grouped a series of dials and pointers
and their connections.
A main circuit line is shown at d³. Four dial plates are shown at A5 A6 A7 A³
and their hands at a¹ a³ as a¹. A series of electric hells are shown on each side
these dials at Bº B B7 B8 and B° B10 B1 and B2. A fixed contact point is
employed upon each side each dial as shown at a³ as a³ a³ and a a10 all and a
and these contact points connect respectively with the bells before named in
the order shown by wires. 6° 6° 67 68 and c³ co c? c³. C³ Ce are ground wires, one

page_text: ees. Each dial
A screw .cup is
h³, and each of
upon each side the instrument outside of the bells. Moreover each bell connects
with the adjacent ground wire by wires d³ de d? ds and es
plate connects with the circuit wire d by a branch wire f³.
employed on each side of each dial.a
1.as at g g g' g³ and h³ h³ h²
these screw cups connects with the adjacent ground.wire C³ or, C by a wire i³.
To operate the various instruments Aº A etc., I connect each. dial plate and a
wire, this wire representing the circuit Z³ a² 63 c² in Figure 4. With each dial
plate I employ a key 'A' and two contact points G³ H³. The contact points H³ are
included in the wire d³-the points G³ are each connected with a dial plate by a
wire I. One end of each key is connected with a dial plate by a wire J.. The
pointers a, as before stated, are always in rotation. When one arrives opposite
the contact point a¹ of his instrument A5 lowers the key of his instrument against
the contact point H³. This opens the circuit through the dial and the pointers of
all the instruments stop on the contact a¹. Furthermore I employ with each dial
a plug, these plugs being shown in order at D³ D D7 D³-and each is connected
with the main line d³ by a wire jo.
The operation by this diagram is as follows-For instance if a subscriber who
is denoted by A³ desires to call another subscriber, say A8, he puts the pointer a
of his instrument at the numeral on his dial representing A³, which for illustration
may be 50 in the diagram. This sets the pointers of all the dials to the same
number and brings the pointer of A³ into contact with his contact point a¹³.
A³ now inserts the plug D5 of his instrument into the screw cup h³ thus
connecting such cup with the main wire d³, and thus closes a circuit from such cup
by way of the main wire d³ and branch wire ƒ³ to the dial plate As, from such
dial A by its pointer a* and contact point a¹ to the wire cs through the electric
bell B¹s and connects with the ground wire C by wire e³, and from this ground
wire by wire back to the screw cup h³ and by the wire 5 of the latter to the
main wire d³.
WHEN
1st. The combination with a series of telephonic closed circuit wires massed
together, with a circuit breaking key to each, of a movable switch board carrying
a device for breaking the circuit through any one of such wires and reestablishing
it through such-switch board.
2nd. A telephonic system embracing a series of telephonic line wires massed
together, a circuit breaking key interrupting each wire, a movable switch board
carrying a device for breaking the circuit through any wire at its key and
reestablishing such circuit through such switch board, and a receiver and trans-
mitter carried by said board.
3rd. In combination a series of telephonic closed circuit wires massed together,
each including a circuit breaking key, a movable switch board adapted to move
from one to the other of such keys, a conducting wire with its opposite ends
secured to conductors carried by said board, which conductors operate to open the
key and break the circuit thereat, and a receiver and transmitter included in the
latter wire.
4th. In combination the wires C, keys B, movable switch board D, con-
ductors ef, wire G, receiver H, and transmitter I, substantially as shown and
described.
5th. The combination with an electric armature escapement and its supporting
frame of an elastic or yielding finger connected with the two poles of the battery,
and in its normal position resting at its free end upon the periphery of the scape
wheel, such finger when in contact with a tooth of the wheel establishing the
circuit, and such circuit being broken when the finger and tooth separate,
substantially as explained.
6th. The combination with an electric armature escapement of a device operating

page_text: upon the scape wheel, substantially as explained, for alternately opening and closing
the circuit through such wheel.
7th. The construction and arrangement of parts, and the method or system of
operating telephonic circuits shown in Figure 4. of the drawings and described in.
the hereinbefore specification. In witness whereof I the said Charles Almon
Jackson have hereunto set my hand and seal this 6th day of November 1883.
CHARLES ALMON JACKSON (LS)
CHARLES ALMON JACKSON (LS)