US942208A - Duplex cable telegraphy. - Google Patents

Description

I. KITSEE. DUPLEX CABLE TELBGRAPHY.

APPLICATION FILED MAY 20, 1908. RENEWED APR. 29, 1909.

942,208. Patented Dec. 7, 1909.

ISIDOR KI'ISEE, OF PHTLADELPHIA, PENNSYLVANIA.

DUPLEX CABLE TELEGRAPHY.

Specification of Letters Patent.

Patented Dec. '7, 1909.

Application filed. May 20, 1908, Serial No. 433,806. Renewed April 29, 1909. Serial No. 492,991.

To all whom it may concern:

Be it known that I, Ismon Krrsnn, a citizen of the United States, residing in the city of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Duplex Cable Telegraphy, of which the follow ing is a specification.

My invention relates to electric telegraphy and more particularly to duplex telegraphy over long lines or circuits, such as long land lines, submarine, subterranean, or aerial cables, or, in fact, any circuit or conductor, especially when having great capacity.

My invention resides in a duplex telegraph system, particularly for use over lines or circuits of the character above described, in which impulses alternating in polarity are impressed upon the line and the reception of signals effected by means of a transformer in whose secondary circuit is connected the receiving apparatus, there being a third coil on the transformer, or associated therewith, for rendering the receiving apparatus at a given station unresponsive to impulses transmitted from that station. And it is characteristic of my system of duplex telegraphy for use on lines or circuits of the kind described that there is no artificial line employed.

My invention resides also in other features hereinafter described and claimed.

For an illustration of one of the forms my invention may take, reference is to be had to the accompanying drawing, in which:

Figure 1 is a diagrammatic view of the circuits and apparatus at two stations adapted to communicate with each other. Fig. 2 is a view of one of the forms of transformer that may be employed.

Referring to Fig. 1, L represents a line conductor, which may be that of a land line, a submarine, an aerial, or a subterranean cable, or, in fact, any conductor, especially when of such length or so disposed that it has relatively great capacity. This conductor L joins two stations, the apparatus at both being similar.

Connected in the line are opposed sources of energy B and B connected in opposition to each other, and one of greater electro-motive force than the other, the line circuit extending through these sources to the earth E, or any suitable return conductor. Connected in shunt to one of the sources, as B is an operators key 70 and a resistance 1, this resistance serving to prevent complete short circuit of the source B when the key is is closed. The two sources B and B with the key 73 and the resistance r, serve as transmitting apparatus whereby impulses alternating in polarity are impressed upon the line. For receiving messages from the other station, there is provided a transformer T whose primary winding P is connected in the line circuit and whose secondary S is closed through the polarized relay R, whose contacts control a local circuit containing a source of current 6 and an electro-magnet m of a sounder, recorder, or any other suitable type of signal translating instrument. In shunt to the primary winding P is connected a condenser K of suitable capacity. This condenser is found to be desirable, though it may be entirely omitted. A third winding, the primary P is associated with the magnetic circuit of the transformer T and is, therefore, in inductive relation with the secondary S. The primary P is connected in circuit with a source of current 13 and the adjustable resistance 1.

While an open magnetic circuit transformer may be employed, I prefer one having a closed magnetic circuit, as shown in Fig. 2, where the core C forms such closed magnetic circuit, the primary P and the secondary S being disposed upon the middle limb of the core, while the primary P may be disposed as shown, upon one of the outer limbs.

The operation is as follows: The operators at the two stations manipulate their keys is in the usual manner to represent dots and dashes, and thereby impress upon the line impulses alternating in polarity. The line having great capacity or great KR (product of capacity and resistance), the impulses received from a distant station are quite feeble but, by means of the transformer T, the first arriving increment of each impulse is transformed and impressed upon the polarized relay R to actuate the same and thus control the local circuit, as explained in my co-pending application Serial No. 422,619. But, while these impulses are being received from the distant station, the operator at the home station may transmit a message to the distant station without interfering with the message coming from that distant station. To this end, the primary P is employed, the manipulation of loo the key is serving to open and close the circuit through the primary P and thereby impress impulses upon the secondary S. The source of energy B is so connected with relation to B and the number of turns in the primary P so adjusted, that the impulses transmitted to line are, so far as the secondary S is concerned, entirely neutralized by the effect produced by the primary P, so that the home receiving instrument does not respond to impulses transmitted to line at the home station. To adjust this neutralizing effect, the number of turns in the primary P may be adjusted, or the source B may be adjusted, or the resistance r may be adjusted. Therefore, it follows that over a line or cable of the character described two messages may be transmitted simultaneously Without interference with each other. And it is apparent that in this system no artificial line or cable is employed.

What I claim is:

1. In duplex telegraphy, the combination With the line, of receiving apparatus comprising a transformer Whose primary is associated With said line, a receiving instrument controlled by the transformer secondary, and a third winding upon said transformer associated with the transmitting apparatus for neutralizing in the transformer secondary the effect of the transmitted impulses.

2. In duplex telegraphy, the combina tion With the line, of transmitting apparatus comprising means for impressing upon said line impulses alternating in polarity, and receiving apparatus comprising a transformer Whose primary is associated With said line, a signaling instrument controlled by the transformer secondary, and a third Winding on said transformer and associated With said transmitting apparatus for neutralizing in the transformer secondary the effect of the transmitted impulses.

3. In duplex telegraphy, the combination With the line, of a receiving instrument connected in a circuit in inductive relation With said line, transmitting apparatus for impressing upon said line impulses alternatmg in polarity, and an inductive connection between said receiving instrument and transmitting apparatus for neutralizing in said receiving instrument the effect of the transmitted impulses.

4. In duplex telegraphy, the combination with the line, of a receiving instrument, oppositely disposed sources of energy, a circuit in shunt to one of said sources including a key, a circuit including the primary of a transformer and said hey, said receiving instrument being included in a circuit in inductive relation to said line and in inductive relation to said primary.

5. In duplex telegraphy without an artificial line, the combination with a line or cable having great capacity, of a receiving instrument connected in a circuit in induct ive relation with said line or cable, transmitting apparatus for impressing current impulses upon said line or cable, and a winding associated with said transmitting apparatus and in inductive relation with the circuit including said receiving instrument for neutralizing in the circuit of said receiving instrument the effect of the transmitted current.

6. In duplex telegraphy, the combination with the line, of a closed magnetic circuit transformer, the transformer primary connected in said line, a receiving instrument connected in the transformer secondary circuit, transmitting apparatus for impressing current impulses upon said line, and a winding associated with the magnetic circuit of said transformer and controlled by the transmitting apparatus for neutralizing in the transformer secondary the effects of the transmitted impulses.

In testimony whereof I have hereunto affixed my signature in the presence of the two subscribing witnesses.

ISIDOR KITSEE.

lVitncsses Amen S. MARsII, ANNA E. Srmnnomc.

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