IMPROVEMENTS IN DUPLEX TELEGRAPHY, AND APPARATUS USED THEREFOR. PRO SP
Year: 1879

page_text: LETTERS PATENT to Richard Theiler, of 86, Canonbury Road, London, N., and
Meinrad Theiler, of 24, Canonbury Park North, London, N., for the Invention
of "IMPROVEMENTS IN DUPLEX TELEGRAPHY, AND APPARATUS USED THEREFOR.
PROVISIONAL SPECIFICATION left by the said Richard Theiler and Meinrad
Theiler at the Office of the Commissioners of Patents on the 1st March 1879.
RICHARD THEILER, of 86, Canonbury Road, London, N., and MEINRAD THEILER,
of 24, Canonbury Park North, London, N. "IMPROVEMENTS IN DUPLEX TELE-
GRAPHY, AND APPARATUS USED THEREFOR."
Our Invention consists in a new method or methods of working a telegraphic
line "duplex," that is, of sending and receiving a telegraphic message simultaneously
through the same wire, by means of which method or methods the artificial line
hitherto in use for the said purpose is entirely dispensed with, and the working
and adjusting of the apparatus is thereby greatly simplified. To attain this object
the contact arm of an ordinary polarized relay (connected with a Morse or sounder)
and the lever of the sending key are connected and work together in such a
manner that when signals in opposite direction are transınitted simultaneously;
and the line current is therefore neutralized, preventing the receiving of such
signals, the contact arm of the said relay is moved against the marking stop
mechanically, and the signal of the sending station is in that case recorded me-
chanically by the receiving station. But as soon as the neutralization of the line-
current ceases, that is, when one of the two keys falls back upon its rest stop, the
key which is still sending into line is prevented by suitable means from moving the
relay arm of its own station, and works the relay of the further (receiving) station
only.
To effect this action of the sending key upon the relay arm of its own station
when the line current is neutralized and to prevent it taking place when such is
not the case, we employ an apparatus which may be constructed in various ways
without deviating from the main feature of our Invention. In whatever form the
said apparatus may be constructed, it is necessary that either the main line battery,
or earth can be brought into contact with the line without moving the relay arm,

page_text: and on the other hand the relay arm must be able to move either against the
marking stop or fall back upon its rest stop without affecting the mechanism which
connects it with the main line battery, or with earth.
One mode of constructing and connecting the said apparatus may be as follows:-
A lever whose movements correspond to and are controlled by the movements of
the key has two springs attached to it which are insulated from one another, one
being connected to earth, the other to the main line battery. These springs
impinge alternately upon the relay arm (which is connected to line) the earth
spring touching when the lever is at rest, the main line battery spring touching
when the lever is moved. The amount of pressure of these springs upon the relay
arm, and their distance from the same can be regulated; one spring does not leave
the relay arm before the other touches, so that the connection either with earth or
with the battery is at no time broken.
The apparatus of each station being connected in this manner, both stations are
always ready to receive. Upon sending a signal the lever which carries the two
springs moves, the main line battery spring touches the relay arm, and consequently
a current is sent through the electro magnet of the sending station relay to line,
and returns through the electro magnet of the receiving station relay, the relay arm
and the earth spring to earth. The current going to line through the electro
magnet of the sending station relay causes an increased pressure of the relay arm
upon the back stop, and thus resists the tendency of the main line battery spring
to move the relay arm against the marking stop, while the yielding of the said spring
enables the sending lever to move, although the relay arm upon which it impinges
stands still. At the receiving station the yielding of the earth spring enables the
relay arm to move against the marking stop, without moving the lever itself to
which the spring is attached. But when both stations send simultaneously, no
current goes to line because the batteries oppose one another; consequently the
electro magnets of the relays do not get charged, and as nothing now counteracts
the tendency of the sending lever to move the relay arm against the marking stop,
the signal is recorded mechanically at the receiving station by the action of the
sending key of the same station.
The two springs hereinbefore described may be attached directly to the sending
key, or the lever which carries them may be worked by the sending key electro-
magnetically.
Various means may also be employed to prevent the relay arm of the sending
station from being moved when working "simplex," and to withdraw such
prevention when the mechanical actuation of the relay arm becomes necessary
by the neutralization of the line current when working "duplex" It is, for
instance, not necessary that the electro magnet of the sending station relay should
perform the keeping back and letting loose of the relay arm, as an independent
electro magnet or other suitable means may be arranged to effect the same object.
When translation of the signals into a new circuit is desired, we use a second set of
apparatus similar to the first, but suitably connected for translation.

page_text: "
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Theiler and Meinrad Theiler in the Great Seal Patent
Office on the 29th August 1879.
86
RICHARD THEILER, of 86, Canonbury Road, and MEINRAD THEILER, of
24, Canonbury Park North, in the County of Middlesex. IMPROVEMENTS IN
DUPLEX TELEGRAPHY, AND APPARATUS USED THEREFOR."
Our Invention consists in a new method or methods of working a telegraphic line
duplex," that is, of sending and receiving a telegraphic message simultaneously
through the same wire, by means of which method or methods the artificial line
hitherto in use for the said purpose is entirely dispensed with, and the working and
adjusting of the apparatus is thereby greatly simplified. To attain this object, the
contact arm of an ordinary polarized relay (connected with a Morso or sounder) and.
the lever of the sending key are connected and work together in such a manner,
that when signals in opposite direction are transmitted simultaneously, and the line
current is therefore neutralized, preventing the receiving of such signals, the contact
arm of the said relay is moved against the marking stop mechanically, and the
signal of the sending station is in that case recorded mechanically by the receiving
station. But as soon as the neutralization of the line current ceases, that is, whon
one of the two keys falls back upon its rest stop, the key which is still sending
into line is prevented by suitable means from moving the relay arm of its own station
and works the relay of the further (receiving) station only. To effect this action
of the sending key upon the relay arm of its own station when the line current is
neutralized, and to prevent it taking place when such is not the case, we employ an
apparatus which may be constructed in various ways without deviating from the
main feature of our Invention. In whatever form the said apparatus may be
constructed, it is necessary that either the main line battery or earth can be
brought into contact with the line without moving the relay arm; and on the other
hand the relay arm must be able to move either against the marking stop or fall
back upon its rest stop, with affecting the mechanism which connects it with the
main line battery or with earth.. One mode of constructing and connecting the
said apparatus may be as follows:-A lever whose movements correspond to and
are controlled by the movements of the key has two springs attached to it, which
are insulated from one another, one being connected to earth and the other to the
main line battery. These springs impingo alternately upon the relay arm (which
is connected to line) the earth spring touching when the lever is at rest, the main
line battery spring touching when the lever is moved. The amount of pressure of
these springs upon the relay arm and their distance from the same can be regulated;
one spring does not leave the relay arm before the other touches, so that the
connection either with earth or with the battery is at no time broken. The
apparatus of each station being connected in this manner, both stations are always
ready to receive. Upon sending a signal the lever which carries the 2 springs
moves, the main line battery-spring touches the relay arm, and consequently a
current is sent through the electro-magnet of the sending station relay to line, and
returns through the electro magnet of the receiving station relay, the relay arm and
the earth spring to earth. The current going to line through the electro-magnet of
the sending station relay causes an increased pressure of the relay arm upon the
back stop, and thus resists the tendency of the main line battery spring to move
the relay arm against the marking stop, while the yielding of the said spring
enables the sending lever to move, although the relay arm upon which it impinges
stands still. At the receiving station the yielding of the earth spring enables the
relay arm to move against the marking stop, without moving the lever itself to
which the spring is attached. But when both stations send simultaneously, no
current goes to line, because the batteries oppose one another, consequently the
electro magnets of the relays do not get charged, and as nothing now counteracts

page_text: the tendency of the sending lever to move the relay arm against the marking stop,
the signal is recorded mechanically at the receiving station by the action of the
sending key of the same station. The 2 springs heroinbofore described may be
attached directly to the sending key, or the lever which carries them may be
worked by the sending key electro-magnetically. Various means may also be
employed to prevent the relay arm of the sending station from being moved when
working "simplex," and to withdraw such prevention when the mechanical
actuation of the relay arm becomes necessary by the neutralization of the line
current when working "duplex." When translation of the signals into a new
circuit is desired, we use a second set of apparatus similar to the first, but suitably
connected for translation. Having thus stated the nature of our Invention, we'
shall proceed to describe by the aid of the accompanying Drawings more fully in
what manner the same is to be performed. Fig. 1 shows how the different parts of
the apparatus for 2 stations are connected. Both keys are represented as being at
rest upon their back stops. The spring a is connected to earth, and its platinized
end touches the relay tongue l, when the key is at rest as shown. The spring 6,
which is connected to the copperpole of the line-battery and is insulated from a,
touches, when the key is depressed only. The polarized relay may be of any
form, but we prefer that shown, as the electro-magnet M can be easily and nicely.
adjusted. The polarized armature N, N, is induced at its axis o, and its oscillation
is limited in the usual way by the stops 1, 2. For the sake of clearness the local
apparatus is not shown in the Drawings. The stop 1 is connected to a Morse or
sounder in the usual manner, while stop 2 is merely a rest for the tongue b. That
part of the tongue 7, which is touched alternately by the springs a and b is of
course insulated from that portion of the tongue which is in local circuit. When
the key, say at station I., is depressed a current will flow in the following
direction-From the battery pole c, through the spring b, the tongue l, and the
relay magnet to line, it will enter the relay magnet at station II., and go thence to
earth through the tongue and spring a. But although the current thus traverses
the relay magnets of both stations, only the tongue of station II. will move, because
the current enters the electro magnet at station I., in a direction opposite to that at
station II. Thus, while the tongue at station II. is moved against the marking
stop 1, the tongue at station I., is pressed against the rest stop 2 by the current.
It will be seen from the Drawing that the key lever t when being depressed has a
tendency to force the relay tongue against the marking stop, this tendency is
counteracted by the magnetization of M at the moment the spring 6 touches 7,
which magnetization has the effect of keeping the tongue pressed against stop 2.
The depression of the key is however not arrested by this stability of the tongue l,
as the spring C will bend when meeting with an obstacle. The same action of
course takes place if station II. depresses its key, and station I. receives. But if
both stations depress their keys simultaneously, no current will go to line, as the
batterics will oppose one another and connection with earth will be broken at both
stations. In this case the signal could not be recorded electrically, as the relay
magnets do not get excited and cannot move the tongue l. But as nothing now
counteracts the tendency of the spring b to force against the marking stop 1, the
signal is now recorded by the mechanical action of the key. It will be seen in
Fig. 1, that the relay tongue 1, has, when moving against the marking stop 1, to
overcome the pressure of the spring a. This may be objectionable when working
on a long line or with a feeble current. Fig. 2 shows a set of apparatus in which
this possible objection does not exist, the relay tongue being free to move without
any impedient whatever. The spring a is done away with, and the connections
are somewhat different from those in Fig. 1. The copper pole of the battery is
connected to 7, the zinc pole (earth) to the key lever t. The platinized end 8 of
the lever t touches the spring b when the key is at rest, and the spring b is
connected to one end of the electro magnet wire, the other being to line as before.
Both stations being connected alike, each is in position to receive. Fig. 3 shows
the key at station II, depressed, and that at station. I. at rest. The current

page_text: established by the touching of e at 1, and the immediate disconnection of s with
the spring b causes the relay tongue at station I. to move against stop 1, while the
relay tongue at station II. is pressed against stop 2 thereby, as herein before
explained. The stability of the tongue t at station 11. causes the spring b to bend
and break contact with s, as shown in Fig. 3. Fig. 4 shows the keys at both
stations depressed. It will be seen that there is now no current to move the relay
tongues, as the batteries oppose one another, and connection with earth is broken
by the depression of the keys. But the tendency of the key to move against stop
1 when being depressed is now unchecked by any pressure of 1 in the contrary
direction, consequently the tongue is moved against the marking stop 1 by the
key mechanically, and a signal is thus recorded without any line current at all. In
the Drawings the key is shown as worked direct by hand, in order to make the
explanation of the system as plain as possible; but in practice we prefer to actuate
the lever t electro-magnetically by a simple make and break arrangement in
connection with a small local battery. In practice, we also make the contacts s
and e equidistant from the axis of the lever t, which could not be plainly shown in
a Drawing.
Having now fully explained the nature of our Invention and in what way the
same can be performed, we wish it to be distinctly understood that we do not
confine ourselves to the form and arrangement of the apparatus, as shown by
Figs. 1, 2, 3 and 4, as the form and construction of the apparatus may be varied
without deviating from the main and novel feature of our Invention, but that we
claim,―
First. The combination of a key with a relay for the purpose, and substantially
in the same manner as herein described and explained.
Second. The construction of any apparatus in which either the relay or the
receiving instrument itself is actuated mechanically, when two opposite stations
send a signal or signals simultaneously.
In witness whereof, we, the said Richard Theiler and Meinrad Theiler, have
hereunto set our hand and seal, this 29th day of August, in the year of
our Lord 1879.