US1387229A - Telegraph system - Google Patents

Description

.I. H. BELL.

TELEGRAPH SYSTEM.

APPLICATION FILED/APR. 9. I918.

1,387,229. Patented Aug. 9, 1921.

JOHN H. BELL, 0E sourn: oEAneE, -1\TEW JERSEY, Ass r'enoElT-o WESTERN ELEcrnrc comrnnr, INCORPORATED, or NEWMYOIRKIV. A CORPORATION or NEW YORK.

TELEGRAPH SYSTEM.

Application filed April 9,

' To all whom it may concern:

Be it known that I, JOHN H. BELL, a citizen of the United States, residing at South Orange, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telegraph sys? tems and more particularly to telegraph transmitting systems.

An object of this invention is to'provide an effective and reliable remedy for the socalled wandering zero effects commonly experienced in connection with telegraphic service over conductors having high electrostatic capacity, such as long land lines or cables and submarine cables.

Another object is to provide a remedy for leakage effects on telegraph circuits as usually causedon open wire lines due to dampness or wet weather conditions, the term leak nullifier being commonly employed in the art in. referring to arrangements for overcoming such leakage efiects.

In accordance with the present invention thereis provided an arrangement whereby an impulse of clearing current having a polarity opposite to the polarity of a preceding signaling impulse will cause a properopposing, neutralizing or current balancing effect in the hue circuit.

v This invention is illustrated diagrammatically in the accompanying drawing in which for the sake of clearness only so muchof av telegraph system has been shown aswill be necessary to a clear understanding of the invention;

In Figure 1 there is shown a terminal equipment for a telegraph line circuit which consists of a single line c'onductor and the usual earth return, arranged in" a manner suitable for carrying out the features of this invention' In F ig. 2 there is shown an arrangement similar to that shown in Fig. 1 except that the terminal" equipment provides for operation over a metallic telegraph circuit formed of two line conductors.

I Fig. 3 illustrates the theoretical effects of current impulses in a telegraph conductor in which no provision is made for clearing or compensating for the :usual wandering zero effects, while in Fig. 4 ofthe drawing, there a is shown a theoretical condition of the cur- Specificationof Letters Patent, 7 Patented Aug. 9, 1921.

1918. SerialNo. 227,567.

rentsin a telegraph conductor on which the ero balancing and the leak nullifying fea tures of the present invention have been applied.

v Aline conductor 1 (Fig. 1) extends from a distant station (not shown) through the windlng of a line relay2, the contacts 4 of a telegraph key 3 anda line battery 6, to

earth.- The battery 6 is also connected over. i

contacts 5 ofvthe key 3through the winding of a relay 7 and a resistance 10, to earth. In transmitting signals from the present statlon, the key 3 may be operated in the usual manner- At eachclosure of the contacts 4L of this key the battery 6 will be connected in series with the relay 2,'t0 the line conductor 1. 5 Contacts. controlled by the linerelay 2 will be understood as arranged for the control of a reading sounder or other suitable telegraph receiving device. In addition to connectingthe battery 6 with the line conductor, eachclosure of the key 3 also connects this battery through the. local relay 7 as already described. Energization of'this relay connects a battery Il1 over the'relay contacts 8 to charge a condenser 12'. The batteries :6 and-11 are of opposite pOlarities.

Therefore, when the key 3 is released to separate its contacts 4: and 5, in addition to cessation ofcu'rrento-f the battery 6 to the" line conductor 11, the relay 7 is released to separate its contacts8 and establish its normal contacts 9. This action of the. relay connects the condenser12 in derived'relation tothe line conductor 1, causing the condenser to discharge and-send to line 1, an impulseof a'polarity opposite .to-that of the preceding signaling impulse fromjthe negative battery 6.

Referrlng to straight line A represents the true Zero potential point: of the line conductor, while the solidline Brepresents the theoretical effectof current impulses. at the transmitting end oft-he line circuit and reading from left to rightgcorrespond with two dots, a dash-and a spacing interval: fThe dotted curved line C represents theoretically, the shape of, current waves at a distantor receiving station on the line, circuit, the electricalcharacteristics of the line having transformed or distorted the current waves B into the condition in which theyare shown by this line C. The current line G, as the'impulses ,c'ontinueto be trans- F ig. 3 of the drawing, the I i Fig. 3, while the solid line D corresponds with currents set up at the transmitting-end of the line by the discharge action of the condenser 12. The dotted line C shows the shape of the resulting wave at a distant receiving station after it has been transformed or reshaped due to the electrical characteristics of the line, as well understood in the art. The current wave C in this figure of the drawing corresponds with the shape of a received current wave, the transmitted impulses forming which have been acted upon by the current clearing or comoensating effects as applied by the presentinvention. This resultant current wave,-

in addition-to showing a better definition between impulses, also continues substan tially balanced with respect to its current values on the respective positive and negative sides of the true zero line A.

Referring to Fig. 2 of the drawing, this alternate arrangement is in general similar to the first arrangement already described except that the line relay is provided with two coils respectively indicated as 2 and 22, while additional contacts 28 and 29 are provided for the relay 7. In tracing a circuit through this terminal equipment, the first line conductor 1 incoming from a distant station is connected through the coil 2 of the line relay, thence through the telegraph key 3, the line battery 6 and the second winding 220i the line relay, to the line conductor 21 which also extends to the assumed distant station. In transmitting message impulses from this station the key 3 con trols the inclusion of the battery 6 in series relation with the line conductors 1 and 21 over the circuits already traced. At each closure of the telegraph key, in addition to establishing the line'circuit through its contacts t, its contacts 5 also complete a circuit through which current from the battery 6 may traverse the resistance unit 10 and the winding of the condenser control relay 7.

-During the time the relay 7 is energized current from the line battery 6 is connected over the contacts 8 and 28 of this relay 1n forming a circuit to charge the condenser 12. On the key 3 being released to separateits contacts 4: in disconnecting the battery 6 from the metallic line circuit, sepa ration of the key contacts 5 also disconnects relay 7, are such that the condenser will be charged in opposite polarity relation with respect to the current impulses, from'the battery 6 to the line circuit. Therefore, at the instant the relay 7 is disconnected the condenser 12 will discharge over the metallically connected line conductors in a direction'opposite to thatof the signaling currents over these conductors.

As indicated in the drawing, thelresistance 10 and condenser 12 may be of variable types and the potential of the battery 11 may also be varied. In this manner a circuit relation may be obtained whereby the relatively short current interval present when the condenser 12 discharges would be such that the residual current remaining in the line circuit following a signaling impulse would be suitably counteracted or neutralized by the current from the condenser. Such condition ofbalance would result in securing the well defined current line' C as shown in Fig. 4: of the drawing.

In describing the manner in which the present system may fulfilthe requirements of a leak nullifier, let it be assumed that the line 1 (Fig. 1) is routed through several intermediate or way-stations, thence through a distant terminal station at which a line battery similar to, but oppositely poled with respect to the line battery 6, is included in the circuit in the same manner as the battery 6. It will, therefore, be clear that during such time as the line circuit may be idle, the batteries at the remote stations form an accumulative series to retain all of the line re-.

sulation may be present due to wet Weather along the route of the line circuit, it now the key 3 is opened as in the operations of sending a message the battery 6 will stand disconnected and the home relay 2 will be re leased. It will be obvious that thepositively poledbattery at the distant end of the line may then continue to flow outwardly over the linecircuit and through the various relays at the way-stationsin proportion to the leakage present along the line conductor. This current will havea tendency to retain the armatures of the line relays at the way-stations and at the distant terminal station irrespective of the open moments of the key 3 at the present terminal station. As a remedy for this condition as applied by the present invention, it will be clear that on the key 3 being released to disconnect the relay 7, a discharge from the condenser 12 outwardly over the line circuit 1 will be in opposite phase or differential with respect to the line battery at the remote terminal station, thereby causing a sufficient cessation in flow of current from the distant line battery to permit the relays at' the way-stations and the distant terminal station to release. In a converse manner, the employment of equipment at the distant terminal station similar to that shown in the drawing will serve as a remedy for line leakage when messages are being sent from that station in a manner similar to that described for the transmission of messages iron the station shown in Fig. 1.

Referring to Fig. 2 of the drawing, the equipment for metallic circuit working shown therein may also act as a remedy for line leakage troubles which may occur from the metallic circuit formed of the line conductors 1 and 21. Inthis arrangement it will be understood that the line relays at the intermediate stations may be connected inseries with the line conductors in the same man ner as the line relay coils 2 and 22 and that a similar but oppositely poled battery may be serially connected in the line loop at a distant terminal station to normally form an accumulative series with the line battery 6. Operation ofthe key 3 in controlling the transmission of impulses and also working the relay 7 to establish counter electromotive forces, results in the condenser 12 momentarily opposing the battery of the distant terminal station, thereby causing a corresponding cessation of current from that battery over the leakage present along the line circuit. In this manner, the relays at-the intermediate stations and also at the distant terminal station may be released and therefore conditioned to respond to the key?) irrespective of the leakage condition of the line circuit, this remedy being eiiective from the distant terminal station when messages may be under transmission therefrom in a manner similar to that described in connection with the present station;

Although .the arrangements shown and described appear to constitute a preferred embodiment of this invention, it will be understood that various departures from this embodiment may be made without departin g from the spirit of this invention.

What is claimed is: s

1. In a telegraph system, a line circuit, equipment comprising transmitting and receiving devices and a source of current serially connected wtih said line circuit for the handling or" message impulses, a condenser, a relay for respectively including said condenser in bridge of said source of current or in bridge of said equipment, and means operated by said transmitter for controlling the operation of said relay.

' '2. In a telegraphsystem, a'circuit formed of two line conductors,'a telegraph transmitter and a source of current serially connected with said line conductors for the transmission of message impulses, a condenser, a relay ior respectively including said condenser in bridge on said source of current or in bridge on said line circuit, and means oper-.

ated by said transmitter for controlling the periods said source of current may be disconnected from the line.

a. A telegraph system comprising a line,

a source of current, a condenser normally connected with said source of current, a transmitting key, and a relay controlled by said transmitting key and adapted upon its deenergization to connect said condenser with said line whereby a current impulse of a polarity opposite to that of the line current present atthe remote station traverses said line. r I I 5. In a telegraph system, a metallic line circuit "formed by two conductors, a terminal station comprising a receiving means, a transmitting means and a source of line current included in series with said line conductors, intermediate stations comprising receiving and transmitting devices connected tical with the station described, at which the line battery is connected to form an accumuloo serially withsaid line conductors, a distant terminal station equlpped' in a manner ideniative series with the line battery at the first terminal station, a condenser'and a relay at each terminal statlon, and means controlled by the ZLSSOOlfiiZGd tl'ELHSHllttGI for rendering said relay effective to respectively 3 connect said condenser to be charged from the associated source of current or to dis- I charge in series with said line conductors in opposite polarity relation with respect to the line battery at the-distant terminal station.

6. In a telegraph system, a line conductor, a terminal station comprislng receiving and transmitting devices, and a source of current connected serlally with said llne conductor,

intermediate 1 stations comprising receiving 7 and transmitting devices connected serially with said line conductor, a distant terminal station comprising equipment identical with the equipment described at which the polar- .ity of the line battery is such that an accumulative series will be formed between the batteries of the terminal stations, a condenser and a relay at each terminal station, means controlled by said relay for connecting said condenser to receive a charge from the associated battery, means operated by a terminal transmitter for controlling the associated relay, and means controlled by said relay for connecting said condenser to discharge over said line circuit in opposing polarity relation with respect to the line 10 battery at the distant terminal station. n

In Witness whereof, I hereunto subscribe my name this 5th day of April A. D., 1918. JOHN H. BELL.

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