Improvements in Simultaneous Telephony and Telegraphy.
Year: 1889

page_text: Date of Application, 21st Jan., 1889-Accepted, 2nd Nov., 1889
COMPLETE SPECIFICATION.
Improvements in Simultaneous Telephony and Telegraphy.
I, EUGENE GWOSDEFF, of 39 Znamenskaya Street, St. Petersburg in the Empire of
Russia, Gentleman, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement: -
The object of this invention is to provide for the sending of telephonic and
telegraphic messages by the same wire at the same time.
In the accompanying drawing, I have shewn, in diagram, various arrangements of
telegraph line to effect the object of my invention, the several figures being referred
to as occasion may require.
A, A', A, A, represent telegraph stations, and I the telegraph line or lines con-
necting them. T, Tare telephones; K, K¹, K2, K³, are condensers; B, batteries,
and E represents the earth. M is an electro-magnet, and S. S' are keys, or telegraphic
instruments.
The mode of working the lines, to effect my object, will now be described.
Suppose there is a telegraphic line, L, between two stations, A. and A', and two
telephones, T and T, are connected to this line through condensers, K and K¹,
by connecting the other end of the wire of each telephone to earth, it is possible to
transmit conversation by these telephones, even while the ordinary telegraphic work is
going on between the two stations, see Fig. 1.
It is, however, indispensable that the telephonic currents, when entering the line L,
should not return to earth at the same station, and in order to prevent this, it suffices
that these currents shall encounter a sufficient resistance in the form of a telegraphic
instrument S, S', or an electro-magnet M.
But with this arrangement of the system, the working of the telegraphic instrument
will always cause noises in the telephone. These noises proceed from two causes, the
first of which is the breaking of the currents, which developes extra currents in the
electro-magnets of the telegraphic instruments, and the second cause is, that the line L
spontaneously is charged with electricity and discharges during the working of the
telegraph instruments.
To neutralize these defects, I employ the following means:-
1. When the telegraphic instruments work with continuous currents, I arrange the
electric batteries of these apparatus in such a manner that their positive poles are
connected with earth, and their negative poles to the line L, and in order to
neutralize the extra currents, I employ, in the telegraphic apparatus, double wire
electro-magnets, the wire being wound in opposite directions, and arranged as shewn
in Fig. 2.
One of these wires, I, is connected to the line L, and the other, II, is short circuited
on itself.
In this manner, the extra currents which are produced in the electro-magnets, will
be neutralised by induced currents in the same direction, which are produced in the
secondary wire of the electro-magnets at each break of the telegraphic current.
The number of coils in the secondary wire should be equal to that in the primary
wire.
When a line, I, serves more than two telegraphic stations, see Fig. 3, it should have
at-the-intermediate stations, A and A', bye-pass condensers, K² and K³, arranged in
such a manner that telephonic currents are not obliged to pass through the telegraphic
apparatus, A and A³, but can take a direct course, which is provided for by the
charges and discharges of the condensers, K' and K.
2. When employing the telegraphic system of working currents, the batteries, B,
at each station, should be arranged in the same manner as the preceding, that is to

page_text: say, the positive pole should be connected direct to earth, and the negative pole to
the line.
Besides this, it is indispensable that the key S should never connect the line L to
earth without the interposition of an electro-magnet.
It suffices for this, to insert a special electro-magnet M (Fig. 4) when using
the ordinary arrangement of telegraphic stations, or it would be well to modify the
arrangement by placing the key, S, between the telegraphic apparatus, A, and the
earth, as indicated at Fig. 5.
The resistance of the special electro-motor, or of the telegraphic apparatus, in this
case, should equal at least 600 Ohms.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The mode of providing for simultaneously telephoning and telegraphing through
one and the same line wire as herein described, the essential features of novelty being,
connecting the positive pole of the battery to the earth, and the negative pole to the
lino, and the employment of double wire electro-magnets for the telegraphic apparatus,
the primary wire being connected to the line, and the secondary wire being short
circuited on itself, as set forth.
Dated this 21st day of January 1889
NEWTON & SON,
Agents for the Applicant.