IMPROVEMENTS IN AUTOMATIC TELEGRAPHY
Year: 1884

page_text: I WILLIAM PHILLIPS THOMPSON Fel. Inst. P. A. of the Liverpool and London
Agency for Foreign Patent Solicitors 6 Lord Street Liverpool in the county of
Lancaster, Civil Engineer do hereby declare the nature of the said invention for
IMPROVEMENTS IN AUTOMATIC TELEGRAPHY and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement :-
The invention relates to the class of telegraphs in which the electric impulses
employed for representing characters are automatically transmitted upon the maiu.
line, and similarly recorded at the receiving station.
The objects of the invention are, to provide means for insuring that the characters
which are employed to represent the messages to be transmitted, and which are
usually formed upon chemically prepared paper at the receiving station with great
rapidity, through the agency of electric currents transmitted from the sending
station, shall be clearly defined and of uniform distinctness, to organize a complete
office system, whereby any number of different operators may be simultaneously
engage in preparing the messages for transmission, and the messages thus prepared
be successively transmitted over a single main conductor without entailing any
material delay in changing from the transmission of one dispatch to another; to
provide means whereby different receiving inst: uments may be placed in circuit
with the main line with the same facility; and in general the aim of the invention
is to organize the apparatus at the station of an automatic telegraph system, in
such a manner as to meet all the requirements of a convenient, expeditious, and
available service.
-
In the system of automatic telegraphy to which the invention is especially
adapted, it is customary for different operators to prepare the messages for
transmission upon cylinders; the cylinders which contain the messages thus
prepared are successively placed in the circuit of the main line, and the contents
of each is then transmitted. When however the contents of any one cylinder has
been transmitted, it has been necessary to replace that cylinder by another, and
transmission has been delayed during this replacement, and the adjustment of parts
to accommodate the new cylinder. By placing each cylinder in the circuit of an
independent local conductor and providing it with the apparatus necessary to
prepare and to transmit the message which may be assigned to it, it is possible to
avoid all delay incident to transferring the cylinders, for each of these local circuits
is arranged to be placed in connection with the main conductor at the will of the
managing operator of the station. When any given conductor is thus placed in

page_text: circuit it forms a portion of the main conductor. After the contents of any
particular cylinder has been thus transmitted, a conductor including another
cylinder, upon which a message has been prepared, is substituted and the work of
preparing the exhausted cylinder with another despatch may at once be cominenced.
The organization therefore is such that the substitution of oue message for another
involves therefore merely the work of changing a switch from one contact-point to
another.
For the purpose of notifying the managing operator when a message is prepared,
an annunciator is placed at the central desk. and a system of local conductors
traverses the several compartments containing the transmitting apparatuses, and
each compartment is provided with a circuit-closer for actuating the particular
annunciator device corresponding therewith. A signalling device is also provided
"whereby the managing operator is enabled to communicate with the transmitting
operator, when the apparatus is ready for the transmission of the particular messages
which he has prepared.
The method of preparing the separate messages for transmission requires a local
circuit for each cylinder, and in each of these circuits is included a key and a
recording pen, adapted to be operated by an electro-magnet, and to register upon
the surface of the cylinder the operations of the key. This is preferably accomplished
by means of spaces corresponding to dots and dashes which are left between sections
of some non-conducting material applied through the agency of the registering pen.
For the purpose of thus registering upon the cylinder the message which is to be
transmitted, it is necessary only that a battery be so connected with the key that
a circuit may be completed thereby through the coils of an electro-magnet employed
for controlling the pen. As there are several of these instruments however, it is
preferable to so organize them that they may be all operated by a single battery..
The circuits are also rendered interchangeable by means of a switch-board so that
any key may be employed for preparing any of the cylinders. The switch-board
is further so organized that any of the registering circuits may be connected with
one of a series of line wires belonging to a minor system, such, for instance, as lines
in city districts, instead of being connected directly with the return conductor of
the battery. This organization renders the system of service for transmitting
directly upon any of the shorter lines of the system, without the intervention of
the automatic devices. A sounder or other receiving instrument is therefore
preferably included in each of the registering circuits for the purpose of rendering
each a complete circuit for manual transmission.
Each office is further provided with one, or more receiving circuits with which
the main line may be connected when imessages are being transmitted thereto from
a distant station. Each receiving circuit is preferably provided with two or more
independent automatic receiving instruments, which may be substituted the one for
the other in the event that any one becomes inoperative during the reception of a
dispatch. With the transmitting and receiving devices is combined an auxiliary
battery, having an electro-motive force less than that of the main transmitting
battery, and of reverse polarity thereto, and two branch conductors containing
artificial resistances extending to the earth from points in the main line near the
transmitting and receiving terminals thereof respectively. The auxiliary or opposing
battery is placed in the same circuit with the transmitting battery, and the currents
which are transmitted from the latter through the receiving instrument, reach the
earth by passing directly through the opposing battery. The circuit of the
auxiliary battery is permanently completed, independently of the transmitting
apparatus, through both branch conductors and artificial resistances. The strength
of this opposing battery is to be governed to accommodate the circumstances at
any time existing and it is found necessary to modify it frequently. For this
purpose it is divided into sections so organized that one, two or more sections may
be connected with the main line through the receiving instrument in series, by a
simple change in the position of a controlling switch.
It is well-known that in fast-speed automatic telegraphs, especially when electro-

page_text: chemical receivers are employed, it is difficult to cause the rapidly succeeding
impulses to be recorded in characters sufficiently distinct and sharply detined to
render the despatch perfectly legible. This difficulty is due to the fact that an
electric impulse, especially when transmitted through a conductor of great length,
becomes prolonged as to its duration, and the character which is recorded thereby,
instead of being a sharply defined dot or dash, is correspondingly lengthened out,
and becomes faint at its commencement and termination, while its interme liate
portion is comparatively distinct.
The action of the auxiliary battery at the receiving station is to normally
maintain upon the main line a continuous electric current of a negative polarity
which will not produce a mark upon the chemical paper. When the transmitting
battery is applied thereto, the excessive electro-motive force of the latter overpowers
the current from the auxiliary battery, and exerts, by means of a positive current,
an electro-chemical action upon the chemical receiving paper, producing a mark.
Immediately upon the interruption of the circuit of the transmitting battery, the
unopposed current from the auxiliary battery at the receiving station flows back
through the paper and into the main line, thereby both neutralizing the residual or
inductive current which tends to flow through the receiving instrument, and serving
to clear the main line from electro-static charge.
The invention will be more readily understood when considered in connection
with the accompanying drawing, in which Fig. 1. is a diagram illustrating the
organization of circuits and apparatus as adapted to the described automatio
system, and Fig. 2. shows certain details of construction. Fig. 3. is a theoretical
diagram illustrating the arrangement of the batteries at the transmitting and
receiving stations together with the circuits.
Referring to the Figs. 1 and 2, the apparatus grouped at A represents that
employed at the central desk in an office of an automatic telegraph system, and at
a¹ a² a³ is represented the apparatus at a series of sub-desks or transmitting desks.
These may all be in the same building or office, or they may be at different points,
forming different sub-stations. The main line of the system enters the office at
the central desk A, where it is connected with a switch B, adapted to continue the
connections of the same with either of the various transmitting instruments, or with
a receiving instrument C, also located at the office.
Considering first the apparatus at the transmitting desks a-Each of these
desks is provided with a cylinder D, of conducting material and preferably
constructed to be rotated slowly when the message is being prepared for trans-
mission and more rapidly while the message is being transmitted.
For the purpose of preparing the message, a marking-pen c is employed which is
adapted to apply a non-conducting ink or gum to the surface of the cylinder when
in contact therewith.
This marking-pen or stylus normally rests against the cylinder but is raised
therefrom through the action of an electro-magnet c' when the latter is vitalized.
The coils of the electro-magnet c' are respectively included in branch circuits of a
battery O, each circuit being also supplied with a key K, of any convenient form.
By simply completing and interrupting the circuit of the battery O!, through the
aid of any key K, the corresponding making-pen will alternately be raised from
and press against the surface of the cylinder, thereby causing spaces to intervene
between the successive sections of non-conducting material applied to the cylinder
by the marking-pen. These spaces depend for their length upon the time that the
key is kept depressed, and correspond thus to the dots and dashes of the telegraphic
code.
The marking-pen and electro-magnet of each cylinder is supported upon a
carriage (not shown) which is caused to move longitudinally with reference to the
cylinder by means of a threaded rod upon which the carriage is supported. The
marking-pen thus applies a spiral line of non-conducting material upon the surface
of the cylinder, as the latter is revolved, and the interruptions of this line caused

page_text: by the depressions of the key K, constitute the dispatch to be transmitted. The
method of transmitting consists in causing a contact-point c, which is connected
through a corresponding conductor or with the switch B, to traverse the
surface of the cylinder along the same line traversed by the marking-pen. This
contact point constitutes one electrode of the circuit of a battery Os, and the cylinder,
the other. The point c is for this purpose supported upon the same carriage with
the marking-pen c¹ each being constructed so that it may be raised out of contact
with the cylinder while the other is being employed. In connection with the
transmitting desk a³; there is represented, in addition to the key K, a key-board
transmitter k of well-known construction. It consists merely of a series of revolving
circuit-closing discs connected with one pole of the battery O¹ and a series of
contact-springs or brushes k³ connected with a conductor leading to the electro-
magnet c³. Each disc represents a different character and is constructed to complete
the circuit of the battery when the corresponding contact or circuit-closing spring
is thrown into the path of the projections, formed upon its periphery, thereby
transmitting impulses corresponding with the character which it is designed to
represent. A switch c is inserted in the branch conductor 3 leading to the key K
at the desk a. This switch is employed when it is desired to use the key-board
transmitter instead of the simple key.
As it frequently happens that it is desired to transmit from one of the desks a,
directly upon some subsidiary line, such for instance as a city line, a switch-board
E is provided. This board is provided with conducting-strips el respectively forming
the terminals of such city lines. The conductors 4 leading from the several desks
are connected with the intersecting rows of contact-dises e. Each transmitting
instrument K may then be placed in connection with any desired subsidiary line by
means of switch-plugs in the usual manner and dispatches may then be sent directly
from the key K without the intervention of the cylinders. To avoid the necessity
of transmitting through the electro-magnets c when this part of the system is
being employed, a switch c is placed in each conductor 4 for short-circuiting the
coils of the corresponding magnet. A relay or other receiving instrument c³ is
also inserted in each conductor 4 whereby the operator is enabled to receive
communications directly from any line with which he may be placed in connection.
The switch-board E is provided with a ground plate es which is connected directly
with the earth by a conductor 5. The conductors 4 are normally connected, by
means of the switch-plugs a directly with this ground-plate, and thus through the
earth with the negative pole of the battery O¹, the positive pole being connected
through the conductor 1 with the contact-points of the several keys K.
It may sometimes be desired to connect two of the local circuits with each other
for various reasons, as if, for instance, it is desired to employ the key-board
transmitter for the purpose of preparing a dispatch upon another cylinder than
that to which it is directly applied. To accomplish this end the switch-board E is
provided with an additional conducting strip e in connection with which any one
of the conductors 4 may be placed through the agency of the corresponding contact-
disc e and switch-plug x. Two conductors 4 being thus placed in connection with
the same strip the two lines will be connected in series.
Referring now to the plan of transmitting upon the main line the matter which
has been transcribed upon the various cylinders, the method whereby the managing
operator at the centrál desk is notified when any cylinder is ready for transmission
will first be considered. One pole of a battery 0 is connected through a conductor
6 with a series of branch-conductors 7 respectively traversing the transmitting
desks or compartments a and leading to the central desk A, where they traverse
the electro-magnets of an annunciator M. These magnets are arranged to control
the signal-drops corresponding to the desks in a manner well understood. At each
of the desks a is placed a push-button f, by means of which the circuit of the
'battery O' may be completed through the corresponding branch-conductor 7, when
it is desired to indicate to the managing operator that any particular cylinder is
prepared for transmissiou. Another system of branch-conductors 8 leading from

page_text: one pole of the battery 03 is provided for enabling the central operator to signal
any one of the transmitting operators when the apparatus at the central desk in
readiness for the transmission of the messages upon his particular cylinder. For
this purpose a push-button fis included in each of the branch-conductors 8 at the
central desk and a corresponding signal bell f is placed at each of the respective
transmitting desks. The push-buttons f may be marked in any convenient way
to designate the desks to which their respective conductors lead.
The conductors 11 etcetera, leading from the respective circuit-closing points c
are arranged to be connected with the main line L through the agency of the
switch B in the following manner: Each conductor leads to a corresponding
insulated contact-pin b projecting from the base 61 of the switch B. The switch-
arm B is pivoted at the centre of the base b¹, and the pins b are arranged in a
circular series so that the arm when revolved may be placed in contact with any
desired pin and allowed to rest upon the same, thereby completing the circuit from
the positive pole of the battery 0³ to the corresponding cylinder, and through the
conductor and switch B to the main line L, whenever the contact-point c* rests
upon the surface of the cylinder. When the contents of any cylinder has been
transmitted, the switch-arm B is moved into contact with any other pin b and the
contents of the corresponding cylinder is in like manner automatically transmitted
through the agency of the contact-point resting thereon. The managing operator,
it will be understood, is able to determine what cylinders are ready for transinission
by simply looking at the annunciator board, for the drops, which have been caused
to fall when the several operators have signalled the completion of the operation of
transcribing upon their respective cylinders the mes-ages assigned to them, are
allowed to remain exposed until the transcribed matter has been transmitted.
As it is frequently necessary for the managing operator to communicate directly
with the distant station, an independent battery O is provided, and one pole. of
this battery is connected with the earth while the other pole is connected with a
conductor 9, including a key F and sounder or other receiving instrument H. The
conductor 9 leads to an annular shoulder b on the switch B. This shoulder is of
such height as to afford a rest for the switch-arm B2, when the latter is placed
between any two pins but not to be in contact therewith when the arm rests upon
any one of those pins. Thus by simply moving the arm B₁ to a position between
any two pins b and allowing it to rest there, the instruments in the conductor 9
will be placed in readiness for use.
When instead of transmitting, it is desired to receive dispatches at the office.
represented in Fig. 1. the switch-arm B is moved into contact with a pin bo which is
similar to the pins b but which is connected through a conductor 10 with a
chemical or other suitable receiving instrument C of well-known construction.
The conductor from this receiving instrument preferably leads through a portion
of a battery 05 to the earth at G. This battery 0' is opposed to the battery
employed at the transmitting station and to a greater or less extent neutralizes
the currents therefrom. In practice it is frequently found necessary to adjust the
strength of the battery 05 and to more readily accomplish this end the battery is
5 divided into sections, a conductor being led from each section to a corresponding
contact-point p of a switch R. The conductor 10 leading from the receiving
instrument C is connected with the switch-arm P¹ of the switch R, and by moving
this arm into contact with one or another of the points p the amount of battery
forced opposed to the transmitting battery may be adjusted as required.
0
The method of receiving will be more readily understood by referring to the
diagram, Fig. 3. In this diagram A¹ and A' respectively represent a transmitting
and a receiving station of an automatic telegraph. These stations are united by the
main line L. At the transmitting station A¹ the battery 0³ has its positive pole
connected by a conductor 12 with the metallic transmitting drum D.
5 may be prepared with the message by means of non-conducting ink, as hereinbefore
described; or a transmitting slip P which has been perforated, in a well-known
manner, to embody the message in the dots and dashes of the telegraphic code,
This drum

page_text: may be drawn between the transmitting point c and the drum D. The negative
pole of the battery O³ is connected with the earth at G¹ by a conductor 15.
A strip of chemically prepared paper N is caused to pass rapidly and uniformly
between the drum M¹ and the stylus m of the receiving instrument C at the
receiving station A', in a well-known manner. The drum M¹ is connected with
the earth by conductors 14 and 13, between which is placed the auxiliary
battery 0s, the positive or marking pole of this battery being connected with the
dium and the negative pole with the earth. The electro-motive force of the
battery 0 is preferably made about one-third as great as that of the battery 0.
Extending from a point o in the main line, near the transmitting station, to the
earth at G¹, is a branch conductor L', containing an adjustable artificial resistance T.
A similar conductor L' extends from a point o!, near the receiving terminal of the
line L, to the conductor 13, in which an artificial resistance T¹ is also included,
this last named resistance being preferably approximately equal to the resistance T.
The proportions of the resistance of the main line and the artificial resistance which
it is preferred to employ, may be approximately indicated as follows: Assuming
the resistance of the main line to be 900 ohms, the resistances T and T' should be
each about 3000 ohms. The main battery O³ should then comprise about 90 cella
and the auxiliary battery 05 30 cells.
The operation of the system is as follows: While the apparatus is at rest,
a constant current from the battery 05 traverses the line L and the branch
conductors L' and L*, dividing itself between them, in inverse proportion to their
respective resistances, in accordance with the well-known law of Ohm. When
electric impulses are transinitted upon the line L from the positive pole of the
battery 0, they will traverse the main line L, the two branch lines L' and L' and
their included resistances, and also the receiving instrument C. The greater
portion of this current will, however, on account of the less resistance offered,
traverse the receiving instrument O and the auxiliary battery 0%. The current
from the last named battery will thus be neutralized and overpowered, and the
excess of current from the main battery O³ will act upon the chemically prepared
paper and record in the form of dots and dashes or like arbitrary characters, the
impulses which are transmitted.
Immediately upon the cessation of each impulse, the auxiliary battery 05 again
acts to send an impulse of positive polarity through the receiving paper and stylus
in the reverse direction and through the line L, which returns to the negative pole
of the battery by way of the artificial resistances T and T. Such an impulse
following immediately upon the interruption of the circuit of the transmitting
battery, acts to destroy the effect of the "tailing" or static discharge of the line L,
upon the receiving instrument, and also to neutralize the same throughout the line.
By thus opposing the discharge of the line by a reverse current transmitted directly
through the chemical paper, a sharply defined record will in all cases be obtained;
and by transmitting the opposing impulse through the line, the latter will be placed
in a condition to receive the next succeeding impulse and to record the same as a
sharply defined character.
The invention has been considered as organized for effecting the impressions by
closing the circuit of the main battery 03; it is evident however that the polarity
of the two batteries may be reversed, the negative poles of each being then applied
to the main line L, and the necessary electric changes produced by interrupting
the circuit of the battery O³. The circuit of the battery 03 will in this case be
normally complete and will be interrupted by the passage of a non-conducting
surface between the drum and stylus of the transmitting apparatus. At the
receiving station the current from the battery 0" will, so long as the battery 03 is
applied to the line, le overpowered and neutralized by the latter and no effect will
be produced upon the receiving paper, When however the battery (³ is
disconnected from the line, the current from the battery 0 traversing the
conductors L' and L' will produce upon the chemical paper a record corresponding
to the duration of the interruption of the circuit. The current from the battery 0

page_text: is immediately overpowered when the battery 03 is again applied to the line, in
the same manner as in the organization first described.
For the purpose of avoiding any possibility of delay occurring by the reason of
the inoperativeness of the receiving instrument C, another similar instrument C¹
(see Fig. 1.) may be placed in a branch circuit 11, and kept in readiness for use.
By simply changing the position of a switch-arms from its contact point s¹, to the
points, this receiving instrument may be substituted for the instrument C.
Although the invention has been described in connection with one particular
system of automatic telegraphy, it is evident that it may be applied with good
results to various other systems. It is evident moreover that more than one main
line L may enter the office at the central desk and be substituted one for the other
as desired.
Having now described the invention as communicated to me I wish it to be
understood that what I desire to protect under letters patent is :-
1st. The combination, substantially as hereinbefore set forth, of a telegraphic
main line, a main battery, means for transmitting electric impulses from said
battery upon said main line, a telegraphic receiving instrument, an opposing
battery having less electromotive force than said main battery through which the
impulses transmitted from said main battery to the receiving instrument are caused
to pass, and two branch conductors, each containing an artificial resistance,
permanently completely the circuit of the opposing battery through the line and
receiving instrument.
2nd. The combination substantially as herein before set forth, of a main circuit,
in which is placed a main battery, a transmitting instrument, an opposing battery
of less electro motive force than the main battery and a receiving instrument, with
two branch or shunt conductors permanently united with the main circuit, one of
which spans the transmitting instrument and main battery and the other the
receiving instrument and opposing battery.
3rd. The combination, substantially as hereinbefore set forth, of a main circuit, in
which is placed a main battery, a transmitting instrument, an opposing battery of
less electro motive force than the main battery and a receiving instrument, with
two branch or shunt conductors permanently united with the main circuit, one of
which spans the transmitting instrument and main battery, and the other the
receiving instrument and opposing battery, and an artificial resistance placed in
each of said branch or shunt circuits.
4th. The combination, substantially as hereinbefore set forth, of a main line,
a main battery, means for transmitting electric impulses therefrom upon said main
line a chemical receiving instrument, an auxiliary battery of reverse polarity placed
in the line adjacent to the said receiving instrument, a branch or shunt conductor
permanently completing the circuit of said opposing battery through said receiving
instrument and an artificial resistance included in said conductor.
5th. The combination, substantially as herein before set forth, of a main line,
a main battery, means for transmitting electric impulses therefrom upon said main
line, a receiving instrument, a series of battery sections adjacent to said receiving
instrument, conductors leading from said sections to a switch whereby one or more
of said sections may be connected in circuit with the main line conductor in such a
manner as to oppose said main battery, two branch or shunt conductors permanently
united with the main circuit, one of which spans the transmitting instrument and
main battery and the other the receiving instrument and the opposing battery
sections, and an artificial resistance placed in each of said branch or shunt
circuits.
6th. The combination, substantially as hereinbefore set forth, of a telegraphic
main line, a series of automatic transmitting devices, means for preparing said
devices with messages for transmission, and means substantially such as described
for connecting any one of said devices with said main line.
7th. The combination, substantially as hereinbefore set forth, of a telegraphic
main line, a series of automatic transmitting devices, means for preparing messages

page_text: to be transmitted from said devices, a receiving instrument, and means, substantially
such as described, for connecting said main line with any one of said transmitting
devices with said receiving instrument.
8th. The combination, substantially as hereinbefore set forth, with a telegraphic
main line, of a station provided with a central managing desk and two or more
subsidiary or transmitting desks each of said transmitting desks being equipped
with an automatic transmitting device, means for preparing messages for trans-
mission therefrom, electric signaling devices for communicating to and from said
central desk and means for connecting any one of said transmitting devices with
said main line.
9th. The combination, substantially as hereinbefore set forth, with a telegraphic
main line, of one or more stations each provided with a series of automatic trans-
mitters, a receiving instrument, and means for placing said main line in connection
with any one of said transmitters or with said receiving instrument and a series of
battery sections more or less of which may be included in the circuit with said
receiving instrument.
10th. The combination, substantially as hereinbefore set forth, at a receiving
station of a telegraphic system of two or more battery sections opposed to the
transmitting battery a receiving instrument, an artificial resistance and means
substantial y such as described for completing the circuit of one or more of said
battery sections through said receiving instrument and resistance.
11th. The combination, substantially as herein before set forth, of a main line an
artificial resistance throu.h which said line is permanently connected with the
earth at the transmitting station, two or more automatic transmitting instruments
and a switch lever through the instrumentality of which any one of said transmitting
instruments may be connected with said maiu line.
12th. The combination, substantially as hereinbefore set forth, of a main line, an
artificial resistance through which said line is connected with the earth, a series
of automatic transmitting devices, a switch for placing any one of said devices
in connection with said main line, and a system of signaling instruments for
communicating from said transmitting devices to said switch, and vice versa.
13th. An automatic telegraph sy stem in which the stations are provided with a
series of automatic transmitting devices, a battery, circuit-closing keys and trans-
mitting devices for prej aring the instruments with messages for transmission,
. a main transmitting battery conductors leading from the transmitting instruments
to a switch for connecting the respective transmitting devices with the main line,
and electric signaling devices for communicating between the points where the
transmitting devices and the switch are located, in substantially the manner
described.
14th. An automatic telegraph system in which the stations are each organized
with a series of automatic transmitting devices, local electric circuits and keys for
preparing such instruments with messages for transmission, conductors leading from
the transmitting instruments to a device for connecting them with the main line
and a switch-board adapted to place the local circuits in d.rect connection with
subsidiary main lines whereby the instruments employed for preparing the
automatic transmitting instruments with messages may also be employed for
telegraphic communication through the subsidiary main lines, all in substantially
the mauner described.