An Improved System for the Distribution of Electric Currents, and Apparatus therefor.
Year: 1897

page_text: Date of Application, 6th Nov., 1897-Accepted, 6th Nov., 1898
COMPLETE SPECIFICATION.
An Improved System for the Distribution of Electric Currents, and
Apparatus therefor.
I, GEORG MÖLLER, of 10, Svanegade, Copenhagen, in the Kingdom of Denmark,
Officer in the Danish Navy, do hereby declare the nature of this invention and in
what manner the same is to be performed. to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to an improved system for the distribution of electric
currents and to apparatus therefor applicable for various purposes and by means
of which considerable economy in the cost of installations can be effected.
The main principle of the invention is to obtain different results by sending
currents of different strengths through the circuit. These currents influence the
main device upon the operation of which the invention is based.
The said device consists mainly of a number of relays or solenoids arranged
in series or parallel and the armatures of which can influence the contact of the
adjacent armatures. In order that currents of different strengths be sent through
this series of relays or solenoids the latter are so arranged that only that relay
which corresponds to the strength of the current flowing at the time through
the circuit influences the contact.
After first describing the main device the use of the same for various purposes
will be more particularly described, for instance, its employment in an automatic
central telephone exchange, in telegraph stations and for signalling purposes.
In short the apparatus can be universally used where electricity is employed in
practice and will to a large extent reduce the cost of installations and simplify
their construction and operation.
The invention is illustrated in the accompanying drawings, in which :-
-:
Figure 1 is a diagrammatic view shewing the system of connections for the main
device:
Figures 2 and 3 are modifications thereof:
Figure 4 is a diagrammatic view illustrating a telephone instrument for use in
connection with the central telephone station illustrated in Figures 7 and 7":
Figure 5 is a detail view of one of the relays shewn in Figure 2:
Figure 6 is a view illustrating a telegraph system:
Figures 7 and 7* are a diagrammatic view of the connections for a central
telephone station or exchange:
Figure 8 is a detail view of the contact apparatus for the central exchange;
Figure 9 shews diagrammatically the main parts of a central telephone exchange
installation for a large number of subscribers:
Figure 10 is a view of a number board hereinafter described.
Figures 11 and 12 shew details thereof; and,
Figure 13 is a diagrammatic view shewing the system of connections therefor.
Figure illustrates the principle of the invention and in order that the same
may be understood the arrangement is shewn adapted for lighting four lamps a¹,
a², a, aby means of four contacts b¹, 63, 63, 64 although it will be obvious that
027

page_text: the said apparatus can also be employed for operating telegraphic or other electrical
apparatus.
In the
To obtain this result it has hitherto been necessary to employ five conductors,
namely, four forward conductors and one return conductor. This invention, how-
ever, enables the same result to be obtained by means of two conductors.
figure indicates the main battery and d, e, d³, d four resistance coils. The
four relays are indicated at e¹, e², e³ and e, f, f¹, f, f³, being the armatures thereof
whilst f is the contact device for the relay e.
In the accompanying description it is to be understood that the word "relay"
can be replaced by the word solenoid."
A battery g is connected up in the lamp circuit. When it is desired to switch
on the lamp a¹ the contact b¹ is pressed whereby a current is caused to flow through
the four coils d¹, d³, d³, d' and the relay e¹ to attract its armature and bring its
spring contact against the adjacent armature f¹. The current then flows through
the three other relays and back to the battery c but its strength is not sufficient
to attract the armatures f¹, f f³. By the contact of the spring-contact h¹ with
the armature f¹ a local current is caused to flow from the battery g through the
armature f, spring-contact h¹, armature f¹, lamp a¹ and back to the battery g and
the filament of the lamp a¹ is therefore rendered incandescent.
The arrangement is such that the current strength, for instance, which is
obtained by removing the resistance coils d', d² is just sufficient to influence the
relay . It will therefore be clear that if it is desired to switch on the lamp a³,
for example, this can be effected by pressing the contact 63. In this case the
current is caused to flow through the coils d³, d relays e¹, 3, e3 are then all
influenced and attract their armatures. The current from the battery g then flows
through the spring-contact 3, the armature f³ and the lamp 3.
Instead of the return line for the relay circuit it will be obvious that the said
circuit can be completed by the earth plates ª, 26.
As the difference between the various current strengths need not be more than
a milliampére or still less, the resistances in the relays and in the transmitting coils
can be so arranged that the current strength which is sent through the circuit is not
disturbed by accidental variations in resistance which may occur in the external
circuit.
Figure 2 shows a modification of the arrangement wherein the lamp battery g
is dispensed with and the main battery c is employed for supplying current to
the lamps.
In this case only three resistance coils d¹, d², dare employed for
controlling the distribution of current to the lamps but a regulating resistance ja
is connected up in parallel with the lamp circuit. The relays are somewhat
altered as indicated in Figure 5, that is to say, the armatures carry at their upper
ends an ebonite plate k to which are connected the contact plate 7, a metal piece m
which forms the upper contact point for the adjacent spring-contact and the
spring-contact h.
The relay coil is connected at one end to the piece m and at the other end to the
spring contact. The contact plate 7 is connected with the lamp. The operation
of the device will now be easily understood. If it be desired, for example, to
switch on the lamp a³ the contact 63 is pressed thereby causing current from the
battery c to flow through the resistance coil d³, all the relays and the resistance j
back to the battery c. The armatures f, f¹, f2 are by these means attracted whilst
the armature does not move as the strength of the current is too low. The
current from the battery now flows through the resistance d³ the relay c¹, spring
contact h¹, connection m³, relay e², spring contact h², connection m², relay e³, spring
contact 3 and from there to the contact plate 3 and lamp ³ to the return circuit.
In the arrangement illustrated in Figure 3 after the current is sent through the
lamp to be illuminated the requisite resistance can be disconnected whereby the
lamp is illuminated. The lettering of the figure is similar to that shewn in
Figure 2 but the contacts 61, 62, 63, 6 are here double contacts so that the middle
key puts the resistance in the circuit and the lower disconnects it.

page_text: 1'
1'
1'
If it be desired to switch on the lamp a³ the contact 63 is pressed and the first
operation results when the middle contact is closed. The current flows through
the resistance d³, relay e, spring-contact h₁₁, spring contact h², relay e², extra
spring-contact h₁, the spring-contact h³, relay 3, extra spring-contact, spring-
contact, relay e, extra spring-contact h₁, and finally through the return circuit
to the battery c. The armatures f, f, f are thereby attracted and the current then
flows through the resistance d³, line A" and the contact 13 and from there through
the spring-contact ³, relay e³, extra spring-contact ³, contact 13 through the
1'
If the contact & be completely
lamp a³ and the return circuit to the battery_c.
depressed the current is short circuited around the resistance d and the lamp is
illuminated.
It will be obvious that the arrangement can be modified in many ways without
altering the principle underlying the invention.
I will now proceed to describe the employment of the apparatus for various pur-
poses and I will first describe how an automatic central telephone station can be
arranged according to my system.
The exchange or station differs from those hitherto in use in that, being arranged
upon the above described principle, the arrangement is much simpler and that it
can at the same time produce results which were impossible with automatic central
exchanges as hitherto known, for instance by its use subscribers can be informed
that the subscriber who is rung up is engaged; two subscribers who are in com-
munication cannot be disturbed by a third and the central exchange itself effects
It is to be
the disconnection when the subscribers themselves forget to do so.
particularly noted that the time which is required to establish connection with a
subscriber is only a fraction of a second.
The arrangement for a telephone exchange is as above mentioned shewn
diagrammatically in Figures 4, 7 and 8 and the following is a description of the
same.
Figure 4 shews the connections of the telephone instrument of a subscriber, the
said instrument and the central exchange being shewn arranged, for the sake of
clearness, for four subscribers although it will be understood that the number of
such subscribers is optional. I have also hereinafter described how large central
exchanges with an unlimited number of subscribers can be fitted up.
When a subscriber desires to ring up another the operation is as follows,―The
current from the signalling battery of the central exchange is conveyed to the
terminal X" of the telephone instrument of the subscriber (Figure 4) and then
relay A, wires 63,
through the circuit 60, lever 61, contact F, line 62, "free"
The circuit
and 64, resistances d', d², d³, d, wire 65, contact G, wire 66, to water.
is thereby completed and the "free" relay attracts its armature and causes the
free" to fall and close the contact H.
disc or the like which covers the word
The bell Bb is then caused to ring by the circuit fed by the local battery of the
subscriber. The ringing continues until the subscriber raises the disc so as to
break the contact H. By now raising the receiving telephone conversation can
be commenced and when finished the subscriber who is rung up has only to replace
the telephone.
"
When a subscriber desires to ring up another subscriber the following is the
method of procedure. The subscriber moves his number arm to the contact button
which bears the number of the subscriber whom he wishes to signal, for instance
subscriber No. 2. By this means the contact G is broken and the subscriber then
pushes the arm C to its lowermost position, as shewn in dotted lines, so that the
inner end of the said arm seizes one of three hooks on the disc R'. This disc is
in connection with the contact disc C which is provided with three strips C, C², C¹³
in connection with the metal disc R. A spring presses against the metal disc
and two other springs and j press against the three strips on the periphery of
the disc C. If the arm be now released it is caused, by a small spiral spring,
to return to its original position and thereby rotate the disc R and the contact
disc secured to it through about one third of a revolution. The two phases in the

page_text: ringing operation are now successively passed through the first phase being as
follows; The contact strip C of the contact disc C makes connection with the
spring t and as the strip is connected to water through the spring v and the line 67
the negative pole of the telephone battery is connected to earth. The positive
pole of the battery PP is connected through the wires 68 and 63, the "free" relay A,
wire 62, contact F', lever arm 61 and circuit 60 to the terminal X" of the telephone
instrument. The current now flows through the line to the exchange which it
reaches through the line relay R² (Figure 7) through which it flows and from
which it proceeds to the tongue T2, the armature contact w', line 4 to the contact z
of the contact device m² from which it flows through 2 and 5 to the line 6 which
is connected to water through the resistance 7. The first phase is now over and
the second phase is passed through a fraction of second later, that is to say, when
the strip on the contact disc C, Figure 4, makes contact with the spring j and
the strip C has passed the spring so that contact is broken and the tongue T³
of the armature for the line relay 12, Figure 7, has been simultaneously attracted.
The tongue T of the armature is then brought against the contact w and the
negative pole of the communication battery B of the central exchange or station
sends current through the circuits 11 and 10, the contact y of the device m², then
through the line 9 and the disconnecting relay N2, line 8, contact w, tongue T2,
line relay R and through the line to the terminal X" of the subscriber.
there the current flows through the wire 60, (Figure 4,) arm 61, contact F, wire 62,
free” relay A, wire 63, wire 64, through the resistances d³, d³, and as the
number arm n, as above described, is against the contact knob of subscriber No. 2,
the current then proceeds through this and the number arm to the wire 69. It
then flows through the " engaged" relay, and, the contact with the strip C³ being
simultaneously operated by the breaking of the contact C with the spring t, further
through the spring and the line 67 to water. The positive pole of the com-
munication battery 15 (Figure 7^) is connected to water through the communication
relays e, e¹, e², e³, e and the resistance M and as the number arm m (Figure 4)
is connected to subscriber No. 2 as above described the resistance coils which are
dispensed with directly determine which armature of the communication relays is
to be attracted; in this case e, e¹, 2, so that the armature of the communication
relay alone can make contact with the next armature f³.
"
From
The operations which are still wanting in order that conversation can begin will
be mentioned when describing the central exchange or station.
When the apparatus is to be disconnected after conversation is finished, the
telephone is hung into its place and the subscriber who rang up presses the dis-
connection contact W. The telephone battery PP is then connected up with the
exchange in the following manner. The current flows from the negative
pole of the battery PP through the line 71, contact W, wires 72 and 67 to
water whilst the positive pole is connected up with the terminal X" by means of
the wires 68 and 63, the "free" relay A, wire 62, contact F, arm 61 and wire 60
and the subscriber's line to the central telephone exchange where the operations
of the current will be hereinafter explained.
In the central exchange or station, which will now be more fully described, there
are for each subscriber a line relay R (R¹ R2 etc.) and two other relays viz., an
intercommunication relay and an interruption relay the armatures of which can
operate a contact apparatus by means of rods or pins. On this apparatus is
arranged a pulley block for the movable telephone cable which ends above in a
cape Figure 8. When two subscribers are in communication with one another
the corresponding contact devices swing in such a manner that the two caps are
seized by the hooks on rods of conducting material so as to effect communication
for conversation. For carrying out the different operations at the exchange or
station, a signalling battery B6, a communication battery B³, an intercommunica-
tion battery B7, an interruption battery 18 and a rod battery B are necessary.
To clearly understand the operation of the central exchange, let it be assumed
for example that subscriber No. 2 wishes to ring up subscriber No. 4. In this

page_text: case the armature of the line relay R² of subscriber No. 2 is attracted as above
described. The communication battery then causes the current to flow through
the communication relays e, e¹, e, e³, e and the resistance M to water. The
relays e, e¹, e, e attract their armatures and the contact point 12 on the spring
contact 4 of the armature of the relay 3 is brought against the
armature f. The circuit from the signalling battery Be of the exchange
is then completed, the negative pole being in connection, through
the wire 6, and the resistance 7 with water, and the positive pole through the
circuits 13 and 14 and the contacts U and U upon the contact apparatus m¹ of
subscriber No. 4 and thence through the line 15, contact 12, spring contact h³,
line 16, contacts P and P1 on the device m and the line 17 with the line of
subscriber No. 4. The "free" relay of subscriber No. 4 is thus operated so
that the indicator falls (the contact H is closed) and his bell rings. The contact
devices of the two subscribers at the exchange are simultaneously swung by
means of the intercommunication battery B7. As to subscriber No. 2, the opera-
tion is as follows, The current goes from the positive pole of the intercommuni-
cation battery B7 through the wires 23 and 19 to the contact o¹; as the armature
of the line relay R2 is attracted, the current then flows through o, line 20,
intercommunication relay 02, lines 21 and 22 to the negative pole of the inter-
communication battery. As the current flows through the intercommunication
relay 02, the armature thereof is attracted so as to swing the contact apparatus m²
into the position for conversation. Current is simultaneously caused to flow
through the contact apparatus of subscriber No. 4 through the following
circuit; the positive pole of the intercommunication battery sends the
current through the lines 23 and 24, the extra spring contact h4,
contact 12", line 25, contact v of the contact apparatus mt, line 26, intercom-
munication relay 0+, lines 27 and 22 to the negative pole of the intercommunica-
tion battery. The contact apparatus m is thereby operated simultaneously with
the contact apparatus m². The two contact devices will now have assumed the
positions given by the two contact apparatuses m¹ and m³ in Figure and in
the following description it will be assumed that subscriber No. 1 has rung up
subscriber No. 3.
During the rotation of the discs mand m³, the contacts Q and Q thereof
touch one another for a moment. The rod battery 19 sends a current through
the rod relay 25 and the lines 31, 30 and 28. The relay is thereby caused to
attract its armature and the rod apparatus is thus raised through a distance equal
to the width of a tooth.
The detail arrangement by means of which this motion is effected is not shown
in the drawing but it is obvious that the power of attraction of the electro-
magnet can effect the lifting of all the rods 36 (Figure 8) to the extent required
by simple mechanical means. Two hooks on the rod 36 engage the two ball
caps at the end of the telephone cable and raise them so that the circuit is
completed through the two caps, the hooks and the rod 36 and the subscribers
can now speak with one another.
During conversation all the contacts of the contact apparatus of subscriber
No. and of subscriber No. 3 have been exchanged as follows. The contact
has come into connection with contact zb, contact P with 2; contact P¹ is free
whilst contacts Q and Q¹ have passed one another. The contact y is broken
and contact U is free, whilst the contact U has been brought against the
contact U2 and the contact is broken. If now current be conveyed through
the two contact apparatuses which are in connection with one another, the said
current will pass through the altered contacts. The telephonic current will
flow from the line circuit of subscriber No. 1 through the line relay R, tongue X¹,
contact W¹, line 34, contact z and contact zb through the cap line 35, cappin
or hook 36, rod 36, pin or hook 36°, cap a³, cap line 37, contact z, line 38,
contact w¹, tongue T of the line relay R, the line relay R³, and through the

page_text: line of subscriber No. 3 to the terminal of the telephone instrument of the
said subscriber.
Figure 8 is a side view of the contact apparatus. The armature O" of the
intercommunication relay 0 carries a rod which operates a ratchet disc (°
loose upon a spindle of the contact apparatus and the armature N° of the inter-
ruption relay N operates a second ratchet disc N keyed upon the spindle, the
pawls being set over against one another. When the intercommunication relay
attracts its armature in order to make connection, in addition to the ratchet
disc (c, there is an ebonite disc (d, which is fast upon the spindle, is operated
by means of a pin on the rod Ob which engages in a notch in the ebonite
disc so as to draw the latter and thereby the whole apparatus in such a manner
that the cap is taken out of the path of the pin 36". When breaking the
contact, if the intercommunication relay be operated the second time, the rod Ob
only advances the ratchet disc 0° to a slight extent so that one of the screws 0°
will close the contact whereby the interruption relay N will receive current
so that its rod will operate the ratchet disc Nb and the whole contact apparatus
will then be returned to its normal position or position of rest by the attraction
of the armature simultaneously with the breaking of the contact D.
It will be understood that as the ratchet disc is provided with a pin 0°
for every two teeth, the contact D is only closed every other time that the ratchet :
disc is advanced by the rod.
"
"
When two subscribers are speaking together, no one can become connected
up with either of them and I will now proceed to describe how a subscriber is
prevented from ringing up a subscriber who is engaged, and how the indicator
upon which engaged is inscribed, falls at the same time in the apparatus
of the subscriber who is ringing up thereby informing him that the telephone
of the subscriber whom he is ringing up is engaged. For instance, it can be
supposed that subscriber No. 2 rings up subscriber No. 3 who is engaged with
subscriber No. 1. The subscriber sends the current through his line relay R²
to the station and current from the telephone battery PP then flows through the
tongue T, the contact W', line 4, contact z, contact z", lines 5, and 6 and
resistance 7 to water. The circuit is therefore closed and the line relay R²
attracts its armature T2 so that the current then flows from the tongue Ta
through the contact w, the line 8, the interruption relay N, line 9, contact y
and the lines 10 and 11 to the communication battery through which it flows
and thence through the communication relay and the resistance M to the water.
The other pole is connected to water through the telephone instrument of sub-
scriber No. 2. The communication relays e, e¹, c²
attract their armatures
because subscriber No. 2 has placed his number arm against subscriber No. 3
whereby two resistance coils are cut out. The contact 39 is now closed and the
current, which flowed through all the communication relays, will now pass through
the contact 39 as follows. The current flows in the manner above described to
the communication relay e, from which it passes through the line 40 and rotates
the contact disc m³, then through the contacts H2 and H, the line 41, the
contact 39 to the spring contact 3, the line 42, the contacts P and 2 to the
contact apparatus m³ of subscriber No. 3 and thence through the wires 43 and 6,
and the resistance 7 to water. The current is thereby caused to flow around
the communication relay e³, the relay e and the resistance M so that the current
strength in the line is much greater. By these means the "engaged" relay B
of subscriber No. 2 (Figure 4) which is arranged to be operated by a current
of this strength, is actuated, the indicator drops by reason of the attraction of
the armature, and the word " engaged," is made visible, it being also made
impossible for subscriber No. 2 to effect connection with the subscriber who is
engaged as the current simultaneously with the fall of the indicator of subscriber
No. 2, flows as above described through the interruption relay № and as the
interruption relays are arranged to work with the same current strength as the

page_text: 86
engaged" relay of the telephone instrument of the subscribers, the said inter-
ruption relay N2 will attract its armature and its rod will then engage with the
toothed wheel of the contact apparatus m² and work as a stop so that the inter-
communication relay 03 which has simultaneously received current, cannot
attract its armature and the whole contact apparatus will then obviously remain
in its original position..
When the conversation has finished, the two subscribers can disconnect as
follows.
Subscriber No. 1, for instance, interrupts the connection with subscriber No. 3
as follows, it being assumed that subscriber No. 1 has rung up subscriber
No. 3. The subscribers hang up their instruments and subscriber No. 1 presses
upon the ringing off key W on his instrument whereby he sends a current from
the latter through the line relay R', the tongue T", contact w¹ and the line 34
to the contact on the contact apparatus m¹ and from there through zb, the cap
line 35, cap ¹, the hook 36", the rod 36, the hook 36°, the cap ³, the cap line 37,
contacts 2b and z on the contact apparatus m³, the line 38, the contact w₁ on
the tongue 13 for the line relay R3 and thence through the relay the line and the
telephone instrument of subscriber No. 3 to water." The circuit from the tele-
phone battery of subscriber No. 1 is then closed and the line relays R¹ and R³
simultaneously attract their armatures. The contact points o and o¹ on the
tongues T and T3 respectively, are thereby closed and the intercommunication
battery B caused to operate as follows. From the positive pole of the said
battery, a current flows through the lines 23 and 44, contacts o¹ and o, the line 45,
the intercommunication relay 0', the line 46 and the line 22 to the negative
pole of the battery. The intercommunication battery is also simultaneously and
in the same manner closed by the intercommunication relay 03. The two inter-
communication relays 01 and 03 will then attract their armatures and the rods
of the armatures will so operate the loose disc 0° upon the contact apparatus
(Figure 8) that one of the screws of the said disc will close the contacts D'
and D (Figure 7 and 7") upon the contact devices m¹ and m³. The interruption
battery B is now closed by the interruption relays N¹ and N as follows. The
current flows from the positive pole of the interruption battery through the
lines 50 and 51, the interruption relay N', line 52, and the contact 1 upon
the contact apparatus of subscriber No. 1 and thence through the lines 53 and 54
to the negative pole of the interruption battery. Current flows simultaneously
through the interruption relay N³ in an analogous manner. The two interrup-
tion relays will then attract their armatures in such a manner that the contact
discs m and m³ are swung into their normal positions. By these means the
hooks S and S3 will engage with the ratchet discs of the wheels Z and 73
and the two caps X and X³ can then no longer be carried by the rod 36 of the
rod apparatus. The latter is put into operation when the contacts Q and Q
upon the devices m¹ and m³ pass one another. The rod relay will then move
the rod apparatus through a distance equal to the width of a tooth whereby
the hooks upon the rod 36 will release the caps which are returned to their
normal position and the connection is broken. It is obvious that the other
subscriber can ring off in the same manner.
When two or more subscribers simultaneously press their keys no one of them
will be put into communication with any other as the currents from the tele-
phone batteries of the subscribers meet one another in the line 6 when flowing
in opposite directions so that not one of the line relays is operated; on that
account the resistance 7, and the signalling batteries, are arranged outside the
resistances d, d which are in the circuit when the instruments are not being
used.
This occurrence will be observed by the subscribers who are ringing up because
the indicator "free" does not fall and each subscriber will therefore ring up
acain

page_text: When two subscribers, for instance, Nos. 1 and 3 forget to ring off, the
exchange itself will do so after the lapse of a certain time, the length of which
can be predetermined. As seen in Figures 7, and 7, the rod devices continually
hold the caps but the latter will turn no more than the length of the cap
circuit permits, and when the caps have been raised to a certain position, the
contact E (Figure 8) on the plate C* (and in connection with subscribers 1 and 3,
the contacts and E³) is closed so that intercommunication is closed and the
ringing off is effected in the above described manner.
The above described telephone exchange is aranged for a single line, but it
will be obvious that it can be easily employed for a double line by doubling
the rods of the rod apparatus and providing a contact device with another cap
line. Furthermore, an arrangement of transformers can, when desired, be easily
arranged between the two rods of the rod apparatus.
When an exchange is to be installed for a large number of subscribers, it is
advantageous to choose the nearest square number or a multiple of a hundred.
If al square number be chosen, the exchange is provided with a
number of relays in rows and the number of relays in a row as also
the number of rows, is equal to the root number. If the exchange
is to be arranged for say 10,000 subscribers, the relays are best arranged in
100 rows with 100 relays in each row. Furthermore, the exchange is provided
with a number of " series relays, of water contact discs and of local batteries,
the functions of which are hereinafter described.
"
In the subscribers' telephone instruments an alteration is made by connecting
the contact disc C (Figure 9) with three instead of with two springs as above
described. Two number arms also are provided one of which is arranged for
thousands and hundreds and the other for tens and units. If, for instance, it is
desired to ring up subscriber No. 5748, one number arm is placed against 57
and the other against 48.
In Figure 9 I have shewn an exchange for nine subscribers and one subscriber's
instrument, and I will now describe how such an apparatus operates, it being
understood that the operation would be the same for an exchange with n sub-
scribers. If, for instance, subscriber No. 1 desires to ring up subscriber No. 5,
he places the uppermost number arm " opposite the cipher 2 and the lowermost
number arm nb also against the cipher 2 as the communication relay of subscriber
No. 5 is a second relay in the second row in the exchange. The three operations
for entering into conversation can be effected as follows. Subscriber No. 1 presses
upon the button C and the lever will then rotate until its other end engages with
a hook or tooth on the disc R. The strip on the contact disc C then engages
with the spring and the telephone battery circuit PP is completed as follows. The
current flows from the positive pole through the wire 81, the "free" relay, the
wire 82, the lever 61, the wire 60 to the terminal X* of the telephone instrument.
It then passes through the line to the central station or exchange where it flows
through the line relay R of the subscriber, the tongue T of the armature and
through the contact w to water. The first operation is thereby finished. The
other operation starts directly the strip C has released the spring and the
strip makes contact with j. The communication battery circuit is now com-
pleted as follows. The current flows from the negative pole of the said battery B³,
as above mentioned, over the contact y upon the contact device of the subscriber
through the interruption relay N, contact w, tongue T of the armature of the line
relay which is now attracted, thence through the line relay R and the line to the
terminal X of the telephone apparatus. The current then flows through the
wire 60, the arm 61, the wire 82, the free" relay, the wire 83, the wire 84 the
resistances d³ and, the number arm n, the wire 85, the spring ; the strip C,
the disc R', the spring and the line 79 to water. The positive pole of the com-
munication battery B5, is in connection through the lines 86 and 87, with the
" series
relays 1, 2, 3 and with water. These series relays have for object to
effect connection between the rows or series of relays which are to be used and
water. The said relays are arranged in a similar manner to the communication
"
*

page_text: relays and therefore make contact with their neighbouring armatures. The cur-
rent flows from the line 87 through the relay 1°, the lines 88 and 90, the water
contact disc, the line 91, the relay 3ª, line 92, water contact disc ³ and through
the line 93 to water. This is the other phase of the current. As the uppermost
number arm n is placed opposite the numeral 2, the current which flows through
the two resistances and d², in the telephone instrument will attract the arma-
tures of the two relays 1 and 2 in such a manner that the contact c2 is closed.
The small local battery B2 in the exchange has its circuit thereby, completed by the
relay which will attract its armature and the water contact disc 2 is, by means
of the rod extending from the said armature, turned through an angle of 90°
in such a manner that the contacts 15 are broken and the water contact disc will
in its new position make contact between P and J. The communication row No. 2
will now be connected to water and the third phase enters into operation. The
negative pole of the communication battery sends current to the telephone instru-
ment of the subscriber in the above described manner through the
wire 83, through the above described path, and the said current then
flows through the wire 94, resistances d³ and d², the number arm nb, the wire 95,
the engaged" relay B, the wire 96 and the spring H to the strip C³ of the
disc C. The disc C has turned to such an extent that C³ has released the spring j
and has made contact with the spring H². The current then flows further
through the disc R. the spring v, and wire 79 to the water. The positive pole is
connected to water through the lines 86 and 97, the communication relays es, e³, e6,
wire 98 and contacts P and J. As the current flows over the two resistances d³
and upon the number board of the subscriber, the communication relays c¹,
and attract their armatures and the relay e will effect contact with the next
armature. The same operations as described above with regard to the exchange
for four subscribers will now simultaneously take place so that the armature of
the communication relay e makes contact with its adjacent armature. The
armature of the communication relay e will then close the contact ³ and thereby
the circuit of the local battery B2 by means of the relay y2 which will attract its
armature for the second time and thereby rotate the water contact disc through
an angle of 90°. By these means the contact between P and J will be broken
and the contact 15 effected.
The bell of subscriber No. 5 has now rung and the exchange is made clear for
conversation. The three phases take place in less than a second. The ringing off
and the operation, when a third subscriber rings up an engaged subscriber, are
exactly as described with reference to the central station for four subscribers.
I will now proceed to describe the employment of my invention in respect to
telegraphy, and as an example, I will describe the arrangements for sending
several messages to several apparatuses through the same line.
The arrangement is shewn in Figure 6. The number of relays, with which the
main apparatus is provided, is dependent upon the number of telegraph appara-
tuses and the relation is given by the following formula, a = 21, where a
indicates the number of relays in the apparatus and n the number of telegraph
apparatuses. In the figure three telegraph apparatuses, a¹, a², a³ are shewn with
three contacts 61, 62, 63 and the connection is effected through the line I and the
return circuit II, which latter can be replaced by earth plates as shewn in dotted
lines.
The arrangement is otherwise a simple application of the main apparatus
and it consists in this case, of seven relays (a === 2-1). The resistances in con-
nection with the three contacts 61, 62, 63 are different and are related to one another
as a series of powers, the base of which is i and the highest power of which corre-
sponds with the number of telegraph apparatuses which is to be used. For in-
stance, the resistance at b' is similar to 23, at 62 to 2, and at 63 to ¹. This must,
therefore, be considered as the most advantageous relation between the resistances
when regard is had to the combination of resistances which is obtained when several
telegraph apparatuses are to be served at the same time.

page_text: As is to be seen from the figure, the current flows from the battery C, through
the line 100, contact 61, resistance 23, the line I, all the seven relays of the appa-
ratus and the return circuit II to the other pole of the battery. As the current
goes through the resistance 23 only the relay e¹, which is arranged to be operated
by the particular current strength corresponding to the resistance 3, attracts its
anchor so that the spring contact h¹ is brought against the contact plate. The
circuit of the local battery g is then completed through the wires 107 and 106,
the telegraph apparatus a, the wires 105, 104, 103, the contacts h₁₁, and the
wires 102 and 101. In the same manner the two other telegraph apparatuses are
operated by the depression of the corresponding contacts.
1'
If b and are pressed at the same time, a current is obtained, the strength of
which is determined by the product of the two resistances and divided by
the sum of the same. The whole resistance will lie between the resistances 2 and 2
so that the relays e¹, e², e³ will attract their armatures. The spring contact h³, then
makes contact with the plate 13, and h³ with 13³. The local battery g is thereby put
into connection with the two telegraph apparatuses a¹ and a². If now be
simultaneously operated by two armatures, the current will be so strong that all
the relays will attract their armatures and therefore the three springs will make
contact with the armature of e7 whereby the local battery g will be connected up
with all three telegraph apparatuses.
With regard to Figure 4, the resistance coils are made so that when the current
passes the coil 3 only the relay e¹, which is actuated by electric currents of this
strength, attracts its armature. If the current passes the resistance coils the
two relays e¹ and 2 are actuated and the contact 2 is switched on. If the current.
simultaneously passes the resistance coils 2, 3by pressing the contacts b¹ and 32
the three relays e¹, e, e will be actuated and the two contacts on the armature for
relay e will be closed. The resistance coils are constructed so that the resistance
coils and in parallel shunting will be larger than the resistance coil i¹, so
that the relay et will not attract its armature as et is made to work for a current
the strength of which is dependent upon the resistance i¹.
If the current passes the resistance the four relays e¹, e, e³, e will be actuated
and the contact at h4 will be closed. If the current passes the two resistance
coils and ³ the five relays e¹, e², e³, e¹ and e5 will be actuated whereby the double
contact between the armatures of e5 and e will be made ready. e6 and e7 will
not be actuated as they are constructed for higher strengths of current. If the
current passes and six relays are actuated and if it passes twelve, whilst
when it passes all seven relays are actuated in the manner above described.
In Figure 10 another arrangement of the main apparatus is shewn. Here it
is used to indicate, in ordinary telephone exchanges, what number a subscriber
wishes to show when a second subscriber who is rung up does not answer the
signal.
The figure shewn is a plan of the number board. Figure 11 shows a locking
relay with a corresponding series relay in the main apparatus. Figure 12 is a
detail of the lock, and Figure 13 is a diagram shewing a method of connecting up
the number board of a subscriber. Upon the front part of the number board
there are twelve contacts, bearing the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, the
words for correction" and a division plate. Furthermore, the contact arm can
be put into two positions "transmitting" and “receiving" according as it is
desired to transmit or receive the message.
In the case of the device there is arranged a row or series of horizontal cylinders
or sleeves 120 (twelve in all) which are provided with flat discs bearing the same
signs as the contact buttons outside the casing. A spiral spring arranged behind
the cylinders presses the indicators against the locking mechanism which is placed
against the front side. If the said mechanism is open, a dise falls through the
flat guide 121 which is provided with a glass front. The locking mechanism of
each cylinder consists of a small angle bar 123 which, by means of a rod device,

page_text: is in connection with the armature of the corresponding locking relay R³ so that
when the armature is attracted a disc drops whilst the other arm of the angle bar
prevents the other discs from falling.
Each of the relays R³ is operated by the corresponding series relay of the main
apparatus, the said series relays ei, e, e³ to e¹ operating as described with
reference to the apparatus as illustrated in Figure 1. When a subscriber leaves
his office, he places the contact 104 upon the knob 122 whereby his number board
is connected up in the circuit. A subscriber who, on ringing him up, receives no
answer although the connection is established, hangs his telephone in place and
presses upon his number contact; if, for instance, the subscriber who is ringing
up has the number 4514, he presses successively upon the numerals 4, 5, 1 and 4.
By these means a current is caused to flow from the telephone battery of the sub-
scriber who is ringing up to water through the relays el to e¹. When the contact
button 4 is depressed, the relays e¹ to attract their armatures and the current
will then flow from the telephone battery PP of the subscriber who is rung up
through the locking relay R so that the said relay will attract its armature
whereby the locking mechanism of the cylinder which contains the discs bearing
the number 4, is freed so that a disc can fall into the guide 121, the discs 5, 1
and 4 falling in the same manner. The button VI is then depressed and the
division plate drops so that any number which is afterwards added is separated
from the number just indicated: When an error is made, for instance, when the
subscriber depresses the wrong button, the indicator bearing the words "for
correction" and marked with IV is caused to fall and the number is then finished.
The guide 121 is provided at its underside with a hinged bottom so that the
discs can be removed and again placed in the cylinders through openings 125.
It is obvious that the number discs can be replaced by a series of type arms
arranged to strike against a strip of paper which moves in the same manner as
that of a typewriting machine. By such an arrangement a code can be so used that
a different arrangement of the numerals can indicate any message which it is
desired to impart to the subscriber who is rung up.
By a small modification of the above described arrangement, a telegraph type-
writing machine can be employed the key board being placed at the transmitting
station and the type machine at the receiving station.
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 is
1. A. system of distributing electrical currents wherein currents of different.
strength are sent through the same line and influence a number of relays or sole-
noids; the armatures of which can make contact with the adjacent armatures; the
said relays or solenoids being so arranged that only the arinature of that relay
which is designed to be operated by the particular current strength at the time
passing through the circuit makes contact with the adjacent armature, substan-
tially as, and for the purposes, herein before described.
2. An arrangement of relays, the armatures of which make connection by means
of spring contacts (h) between the adjacent armature, a local battery
and the device to be supplied with current when the contact corresponding to the
said relay is pressed at the transmitting station whereby current from the
transmitting battery (c) is caused to flow through one more resistances
So that the armature
at the transmitting station through the relays
ог
for the relay which is arranged to be operated by the particular current
strength at the time in the circuit, is attracted with the armatures of the relays
which are arranged to operate with weaker current strengths whilst the current
of the local battery is caused to flow through the device corresponding to the
contact depressed by means of the closing of the spring contact of the armature of
the relay corresponding to it upon the armature of the adjacent relay which is
not attracted, substantially as hereinbefore described and illustrated in the accom-
panying drawings.

page_text: 3. An arrangement of relays which are designed to be operated by particular
current strengths determined at the transmitting station by causing the current
to flow through one or more resistances whereby the relay which is designed to
operate with the particular current strength will, together with the relays
arranged to operate with weaker current strengths, attract its armature
whereby the contact (h) and the connection (7) Figure 2, will be constantly in
connection with the attracted armatures, the contact (h) of the armature of the
particular relay breaking contact with the connection upon the adjacent un-
attracted armature and making connection with one of the other contacts whereby
current is conveyed from the transmitting battery through the contact 7 and the
device to be supplied with current in such a manner that, as the resistances in
the relays correspond to the resistances in the transmitting station, each of the
devices is supplied with current of the same strength, substantially as herein-
before described and illustrated in the accompanying drawings.
4. The modification of the arrangement described in Claim 3, whereby current,
after the contacts have been closed, is conveyed through a double contact or key
at the transmitting station around the resistances at the same place and around
all the relays except that relay which, when the contact with the adjacent armature
has been closed, conveys current through the device which is to be supplied, sub-
stantially as herein before described and illustrated.
5. An arrangement of the kind described in Claims 1 to 4 for automatic electric
central stations wherein the relays, the armatures of which make contact with
the adjacent armatures, are employed for effecting the operations necessary for
an automatic central telephone station, substantially as herein before described.
6. In a central telephone station of the kind described in the preceding claim-
ing clause, the arrangement of a contact apparatus with an arrangement of con-
tacts which can be combined with the contacts of the main device in various ways
so that a current in one case is conveyed through the contact apparatus of the
subscriber who is ringing up through the main device (here called the communica-
tion relay) and by its operation causes a local current to flow through the contact
apparatus of the subscriber who is rung up and through the
line
of the said subscriber in order to effect the signalling operation, the said current
in another case, that is to say, in the case where a third subscriber desires to
become connected up with one of two subscribers engaged in conversation, being
conveyed through the contact apparatus of the said subscriber and through the
communication relay after which the said current, which has influenced the com-
munication relay of the subscriber who is rung up, is passed through resistances
at the central station (and without effecting connection with the subscriber who
is engaged) whereby the current strength is increased in the circuit so that a
relay in the instrument of the subscriber who is ringing up and which is arranged
for operating at the increased current strength, is influenced and causes an arm
to fall thereby informing the said subscriber that the subscriber he wishes to ring
up is engaged, substantially as herein before described.
7. In an automatic central telephone station of the kind described in Claims 5
and 6, the arrangement at the said station of a relay for each subscriber which,
by means of the small local battery of the subscriber, enables connection with the
large communication battery of the said central station to be effected, substantially as
herein before described.
8. In automatic central telephone stations of the kind described in Claims 5, 6
and 7, the arrangement whereby the connection between two subscribers is effected
by means of a movable rod apparatus with parallel loose rods provided with
hooks which seize conductor caps and raise the same, the said caps, when con-
nection is to be broken, being prevented from taking part in the movement of
the rod apparatus so that the hooks release the caps and break the connection,
substantially as herein before described.
9. In automatic central telephone stations of the kind described in Claims 5,
6, 7 and 8, the arrangement whereby the interruption of the connection between

page_text: two subscribers is automatically effected by the closing of a contact when the
rod apparatus is raised over a suitable device whereby the operations necessary
for the ordinary interruption are enabled to take place, substantially as herein-
before described.
10. In automatic central telephone stations of the kind described in Claims 5
to 9, the arrangement whereby the rod apparatus is provided with double rods
corresponding to the double contact apparatus for each subscriber so that the
double circuit can be employed, substantially as hereinbefore described.
11. In automatic central telephone stations of the kind described in Claim 10,
the arrangement whereby transformers are introduced and wherein the rods are
used as transformer cores, substantially as herein before described.
12. In a central tele; hone station for a large number of subscribers, the arrange-
ment wherein the communication relays are arranged in rows with a
"series" relay
with a water contact disc for each row and wherein the current from the com-
munication battery is first conveyed through the series relay so as to influence the
water contact disc which places the desired row of communication relays in con-
nection with water, the said water contact disc simultaneously interrupting the
current flowing through the series relay so that the said current is now conveyed
through the desired row of communication batteries to water and the communica-
tion relay of the subscriber whom it is desired to signal is influenced and the
water contact disc returned to its normal position.
=
13. In a central telephone station of the kind described in Claim 10, the
arrangement in the subscribers' instruments of resistances arranged upon a
number board in such a manner that one of two number arms represents thousands
and hundreds, and the other tens and units, substantially as herein before described.
14. A device of the kind described in Claim 1 for telegraphy wherein the
number of relays in the said device is determined from the formula, a 2º-1,
and the armatures of the relays are provided with contacts and together with a
relay are so arranged that the closing of the contact with the adjacent armature,
is effected in consonance with the closing of the contact at the transmitting
station whereby it is rendered possible to send a number of messages simul-
taneously through the same line, substantially as hereinbefore described and
illustrated in the accompanying drawings.
15. A device of the kind described in Claim 1 whereby a subscriber who has
rung up another subscriber can register his number on the instrument of the sub-
scriber he has rung up and wherein the telephone instruments are in connection
with a number of relays at the receiving station for opening a row of number
cylinders in order to allow discs bearing the numerals forming the number to
fall into a receiver, substantially as herein before described.
Dated this 6th day of November 1897
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.