Improvements in Telegraphic Apparatus.
Year: 1894

page_text: Date of Application, 20th Feb.. 1894
Complete Specification Left, 19th Nov., 1894-Accepted, 22nd Dec., 1894
PROVISIONAL SPECIFICATION.
Improvements in Telegraphic Apparatus.
We, THE PHONOPORE COMPANY LIMITED, of Faraday House, Charing Cross
Road, in the County of London, and EDWARD WYTHE SMITH, also of Faraday
House aforesaid, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to means of increasing the transmitting capacity of.
telegraphic and such like conducting lines. For this purpose we employ as a
transmitter an induction coil the circuit of the primary coil of which with the
battery is closed by operating keys and a vibrating tongue, so that as long as one
of the keys is depressed the tongue continues to vibrate. The secondary coil which
thus has alternating currents induced in it may form part of the line or it may
connected at one end with earth and at the other end with the line a condenser
being interposed in either or both branches. Also the secondary coil may be wound
double as in a phonopore transmitter, the two coils having no conducting connection
with each other, the one led to earth, the other to the line or both connected in
shunt to the line. The receiver may be a telephone receiver or like instrument of
any known construction giving audible signals corresponding with the vibrations
of the tongue of the transmitter or the receiver may be a single needle instrument.
In the latter case we employ two line wires and two relays each having its
armature which vibrates but is so adjusted by springs and stops that it exerts
greater alternating with less pressures in the contact stop in the circuit of a local
battery and the receiver the position of the needle depending on the differential
action of the relays. These relays are not in the line but are connected thereto
by any one of the transmitting devices above described. The telephone receiver
may either form part of the line or be connected to the line in like manner.
prefer to connect the receiver to the line through the transmitter. The line to
which transmitters and receivers as above described are applied is not interfered
with in its ordinary telegraphic use.
We
When the receiver is a telephone receiver, although one vibrating tongue of the
transmitter is sufficient we prefer to use two, so as to produce two distinct sounds ;
and in order to overcome the induction from other sources and to increase the
strength of the received signals we substitute for the telephone a relay similar to
those described, and place the telephone in a local circuit governed by this relay.
As sending key we use an instrument similar to the ordinary single needle handle
but having contacts so arranged that when the handle is in the middle position
the receiving instrument is in the circuit and the primary circuit of the coil is
closed without the battery, and that the battery circuit is closed through one of
the vibrators and the primary of the transmitting instrument in either of the
sending positions, the receiving instrument at the same station being at this time
cut out of circuit; and when using two line wires one only is connected with the
transmitter coil in each of the sending positions of the handle.
In order to prevent the ordinary signals in the line from interrupting those
transmitted as above described, we alter the ordinary instruments so that the line
circuit is never severed. For instance, in the case of an ordinary single needle
instrument, we arrange that the battery connections are made just before the line
is opened and that the battery is not disconnected until the line is closed. In the

page_text: case of a Morse key we arrange contacts as springs so that the front contact is
closed before the back one is broken; and we alter all other keys in like manner..
Condensers or phonopore coils may also be placed as shunts either to the keys
or to the whole of the ordinary instruments.
Dated this 20th day of February 1894.
ABEL & IMRAY,
Agents for the Applicants.
Improvements in Telegraphic Apparatus.
We, THE PHONOPORE COMPANY LIMITED, of Faraday House, Charing Cross
Road, in the County of London, and EDWARD WYTHE SMITH, also of Faraday
House aforesaid, Electrical Engineer, 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 :-
This invention relates to means of increasing the transmitting capacity of
telegraphic lines. For this purpose we employ as a transmitter an induction coil
the primary coil of which, with the battery, is closed by an operating key and two
vibrating tongues so that, whilst the key is depressed on either side, the corre-
ponding tongue continues to vibrate. The secondary coil, which has thus
alternating currents induced in it, is connected at one end with the line and at the
other end with earth or another point on the line, a condenser being interposed in
either or both branches.
The secondary coil may be doubly wound as a phonopore coil described in the
Specification No. 7799 of 188., the two wires having no conducting connection
between them, the beginning of the one and the end of the other being the
terminals; in this case no auxiliary condenser is required. As a receiver, which
is included in one of the branches of the secondary coil, we employ a telephone
receiver or like instrument of any known construction, giving audible signals
corresponding to the currents passing through it. In cases where the received
currents are not strong enough of themselves, we substitute for the telephone
receiver a relay and place the telephone receiver in a local circuit, governed by
this relay. As sending key we employ an instrument similar to the ordinary
single needle handle or double tapper key, but having contacts and contact pieces
so arranged that, when the key is in the receiving position, the primary circuit of
the coil is closed without the battery, and the battery is closed through one of the
vibrators and the primary coil, when the key is in either of the sending positions,
the receiving instrument at the same station is short circuited or shunted with a
resistance so that only a comparatively small part of the outgoing current passes
through the receiving instrument.
In cases where the ordinary signals in the line would interrupt those transmitted
as above set forth we alter the ordinary instrument so that the line is never severed.
For instance, in the case of the ordinary single needle instrument we arrange that the
battery connections are made just before the line is opened and that the battery is
not disconnected until the line is closed; when a Morse key is employed we use
springs as contacts so that the front contact is made before the back contact is
broken.
Condensers or phonopore coils may also be placed as shunts either to the keys or
to the whole of the ordinary instrument.
Fig. 1 of the accompanying drawings is a diagrammatic sketch of an instrument
and its internal electrical connections according to this invention. C and Z connect
to the terminals of the local battery, E connects to earth or line or return line,
L connects to line. R is the telephone receiver and H the handle. The handle H

page_text: g
is shewn in the middle position for receiving. Under this condition the primary
coil P P is short circuited through the springs p p by the insulated strap q.
When the handle H is held over to the one side, the strap 9 leaves one of the
springs p, and the battery circuit is closed from C through the primary coil P P
by the flexible conductor F to the spindle of the key thence through the contact
piece K to one of the springs a b, to a vibrator A or B back by Z to the battery.
The secondary circuit & ss is at its one terminal connected through the
receiver R to line L and at the other by E to earth, return line, or another point
in the line. When the instrument is sending, the receiver R is shunted through
the resistance by the flexible conductor and the insulated strap coming in
contact with the spring. If a coil with a single secondary used, we place a
condenser in the secondary circuit either between s' and E or s and L or in both
lines. We also use a small condenser or condenser coil c to diminish the sparking
at the vibrator contacts A and B.
The object of the resistance r is to allow enough of the outgoing current to pass
through the receiving instrument for the operator to know that his instrument is
working, but not so much as to produce an objectionable noise or to interfere with
the adjustment of the relay. We find that we get the desired result when the
resistance r does not exceed th of that of the receiver.
Fig. 2 is a diagram shewing how the instrument I is connected to line L
local battery B and earth E, an inductive resistance R¹ being interposed between
the point of the line to which I is connected and the ordinary needle instrument O.
Fig. 3 shews the instrument I connected as shunt to part of the line L the
resistance R¹ being in this case between the points of the line to which the
instrument I is connected.
Instead of the simple telephone receiver R shewn in Fig. 1 we may connect at
the points t t a combined relay and telephone receiver R in a local circuit as
shewn in Fig. 4. The contact K is preferably made of carbon and the receiver R
is placed in the secondary circuit of an induction coil Q.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The combination of an induction coil having two vibrators the secondary
circuit of the coil containing a condenser or being doubly wound with a telephone
receiver as receiving instrument and a drop handle key or double tapper key with
the necessary contacts, substantially as and for the purpose set forth.
2. In combination with apparatus such as is referred to a relay governing a local
circuit in which the telephone receiver is placed substantially as described.
Dated this 10th day of Nonmhow 1001
ABEL & IMRAY,
Agents for the Applicants.