Improvements in Synchronous Multiplex Printing Telegraphy.
Year: 1885

page_text: Improvements in Synchronous Multiplex Printing Telegraphy.
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I, SYDNEY PITT of Sutton in the County of Surrey, Gentleman, do hereby
declare the nature of the said invention for IMPROVEMENTS IN SYNCHRONOUS
MULTIPLEX PRINTING TELEGRAPHY, a communication to me from abroad by
Patrick Bernard Delany of New York City, State of New York, United States of
America, Electrical Engineer and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement :-
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The general class of synchronous apparatus to which my invention more
especially relates is shown in my British Patent No. 4787 of Oct. 9, 1883, to
which reference is made for a full description.
In the drawings I have shown the application of my synchronous telegraph
system to printing telegraphy, by which the number of independent circuits may
be very largely increased.
In Fig. 1 two connected stations X and Y are shown each having a branch line
connected to a single contact. In this diagram the 9s and 10s on the table of
contacts A at each station are to be utilized for maintaining the synchronous
movement. When the trailing fingers A' are moving synchronously and come
upon corresponding contacts at the stations there will be momentarily a completo
and independent circuit from the branch line connected with one of the contacts
at one station to the branch line connected with the contact at the other station.
If a printing, registering or indicating telegraphic apparatus be connected with
each of the working contacts at these stations with suitable batteries and trans-
mitters such instruments will be placed in brief communication with each other
during each revolution. If the rotating circuit-completers A' rotate three times a
second each pair of branch lines will get three impulses a second. These impulses
may be utilized to actuate the sending and receiving apparatus. If such apparatus
is of the ordinary step-by-step character so as to be manipulated by successive
completions of the circuit to print, register, or indicate the letter or word trans-
mitted, it is obvious that messages may be transmitted as accurately between each
pair of corresponding instruments as if the line were devoted exclusively to their
use. Thus, with a table of 80 contacts connected by a single main line, 72 private
and independent circuits will be obtained between the two stations.
The transmitting and receiving apparatus at the two stations is preferably of the
simplest character, so that skilled operators may be dispensed with. Such
apparatus, either dial instruments or alphabet printers, are well known.
Referring specially to Fig. 1, a corresponding contact at each station is shown as
connected through the coil of a relay R to earth. A description of one pair of
branch circuits will of course be sufficient.
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From the relay R the line may be connected with the battery M B through a
key K. or put to ground by a switch S The key K stands for a letter-board of a

page_text: printing telegraph transmitter. The terminals of a local circuit are connected
respectively with the armature of the relay R and its back stop. An electro-
magnet B in this circuit actuates a pivoted push lever C acting on a toothed wheel
on a shaft c which carries the type-wheel. With the switch S at station X put
over so as to include the key and battery in the circuit, and the line put to ground-
at station Y, the operation is as follows:
[
When the
The key K at station X is normally open. A pointer on the end of the shaft c
of the printing apparatus, Fig. 3, traverses a dial bearing the letters of the
alphabet, or such other signs as are to be transmitted. The pointers at both
stations rest normally upon the zero point. If the key K at station X is depressed
the impulses transmitted over the main line to the relay R at station Y open and
close the normally closed local circuit and vibrate the lever C, thus causing the
dial pointer and type-wheel to rotate. This occurs at both stations.
finger on the dial therefore reaches the letter or sign which is to be printed, the
operator at X lifts his finger, opens the circuit, and the pointer and type-wheel at
both X and Y pause. The key is then depressed until the apparatus is rotated to
the next signal or letter. If it is desired to print as well as indicate a signal on
the dial, a strip of paper is fed between the type-wheel and the pivoted printing
lever F in the usual way. An arm G extends from the rocking push lever C
partly across the face of a disk H. This disk is carried upon a spindle I of the
clock-work. It is loosely mounted thereon, but is in frictional contact with a
disk i fast on the shaft. The amount of friction may be regulated by a thumb-nut
and spring on the end of the shaft. A pin h projects from the face of the disk into
the path of the arm G. The friction disk H also. carries a contact finger k which
is arranged in such proximity to another contact finger k' that a comparatively
small movement of the disk H is required in order to bring the contacts kk'
together and complete a local circuit m. This local circuit includes the coils of a
magnet which operates to throw the printing lever up against the type-wheel
and print the desired character. The pin h on the disk H is in such relation to
the end of the arm G that when the key at the transmitting station is kept closed
and the magnet B is energized with comparative rapidity-three times more or
less a second-to rotate the type-wheel, the pin his constantly snubbed back by
the end of the arm G so that the disk H is never permitted to rotate a sufficient
distance to bring the contacts kk' together; but when the key at the transmitting
station is opened to indicate or print a signal, one or more periodic impulses are
prevented from entering the line and the vibrating lever C and arm G carried
thereby remain at rest a longer period; and as the local circuit is completed the
magnet B keeps the lever C drawn down so as to elevate or move the arm G away
from the pin h. This permits the tardy circuit-completer to complete the local m
at the contacts k ke', when the strip of paper is thrown up against the type by the
printing lever F. When the transmitting key at the distant station is closed the
step-by-step rotation of the apparatus is again continued, the pin h being snubbed
back by the arm G so as to open the local m.
The printing apparatus described is well adapted for the purpose, but my
invention is not limited to this nor any particular apparatus.
Should an increased speed of the printers be desired, the corresponding branch
lines may be connected with two or more contacts in the circle. Under my
improved system a record of all messages transmitted and received may be
preserved by the parties. No spoken words are necessary, and the messages
transmitted can be kept absolutely secret. It is absolutely impossible for a line
at any point to be tapped.
My system contemplates the establishment of exchanges in cities connected by
one or more main line wires, so that the private line subscribers in both cities may
communicate with each other.
The apparatus above described is well adapted for carrying out my invention,
but I do not limit myself to it, nor to any particular form of tardy circuit-completer.
So far as I am aware I am the first to use a tardy circuit-closer..

page_text: One or more Morse circuits may be worked on the same wire in connection with
the printing circuits. Such an organization is illustrated in the diagram view,
Fig. 4, in which the stations marked 1 are connected in a printer circuit having
one impulse per revolution. The stations marked 2 are connected in another
printer circuit having three contacts in a series, as clearly illustrated; and the
stations marked 3 are connected for Morse transmission, as described in my patent
before mentioned. The Morse circuit is preferably provided with six contacts
taken at equal intervals in the circle so that when the apparatus rotates three
times a second, eighteen impulses will be transmitted over the Morse circuit, thus
giving a practically continuous circuit for telegraphic purposes. There may be
several Morse circuits and several printer circuits of different speeds.
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 as my Invention
1. The combination, substantially as set forth, of a main line, synchronously-
actuated apparatus at each end of the main line, a table of independent working
contacts at each end of the main line connected in branch lines at each station, the
corresponding branch lines being connected with one or more corresponding contacts,
and step-by-step printing, or indicating apparatus in the branch lines, for the
purpose set forth.
2. The combination, with the main line, of synchronously-actuated apparatus at
each end of the main line, a series of insulated contacts at each station, mechanism
for successively placing the main line in connection with each of said contacts,
step-by-step printing or indicating apparatus connected in branch lines at each
station, corresponding branch lines being connected with one or more corresponding
contacts at the stations, and other of said contacts placed at intervals around the
table through which correcting impulses of electricity are sent over the main line
to insure the synchronous rotation of the two apparatus.
3. The combination of the main line, the relay actuated by periodic impulses of
electricity transmitted over the main line, the actuating inagnet and its local
circuit which is made and broken by said relay as the impulses are transmitted
over the line, the print magnet, and the tardy circuit-completer which completes
the print magnet circuit when a more than normal period of time has elapsed
between said impulses.
4. The combination of the step-by-step mechanism of a printing telegraph, the
receiving instrument, an electric circuit over which impulses of electricity are sent
to advance said mechanism, the print magnet, its circuit, and a tardy circuit-
completer in the circuit of the print magnet, for the purpose set forth.
5. The combination of a single main line, Morse instruments at each station
connected in corresponding branches of the main line, step-by-step printing
apparatus at each station also connected in corresponding branch lines, and
synchronously-actuated circuit-apportioning or distributing devices at each end of
the main line by which the main line circuit is successively completed between
ench pair of corresponding instruments, whereby combined Morse and step-by-step
transmission is accomplished over a single main line.