US1724803A - Cable telegraphy - Google Patents

Description

Aug. 13, 1929. c. F. NELSON CABLE TELEGRAPHY Filed Jan. 15, 1928 2 Sheets-Sheet IMQIOONK OF 2E Q33 ...on

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C. F. NELSON CABLE lTELEGRAPHY Filed Jan. 13, 1928 CABLE POSITION OF RELAYS A-B FOR DOT SIGNAL III-III CABLE POSITION OF RELAYS A'B AT BEGINNING OF DASH SIGNAL CABLE POSITION 0F RELAYS A-B AT END 0F DASH SIGNAL CABLE POSITION OF RELAYS A- FOR sPAcE SIGNAL NIH I 2 Sheets-Sheet 2 'wl IW convtn'reo w suman.

DOT 2" ELEMENT oFA DASH I I Y ZERO OR SPACE ggy rnmsmrrso AND RECE' VED SIGNLS Jj@ z :Inventor Gtforncg Patented Aug. 13, 1929.

UNITED STATES PATENT oFFicE.

CRESCENT F. NELSON, OF NEW DORP, NEW YORK, ASSIGNOR TO THE WESTERN UNION TELEGRAPH COMPANY, OE NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

CABLE TELEGRAPHY.

Applicationlled January 13, 1928. Serial No. 246,580.

condensing it into a signal made up of av smaller number of signal impulses, in the ratio of 2 to 1 or any other suitable ratio, in

accordance with a predetermined conversion key, transmitting the condensed signal, receivingA the condensed signal and automatically converting it back into the original signal by a complementary l to 2, or the like, transformation.

Vhen applied to the conversion of a Wheatstone-Morse code signal into one utilizing cable Morse code signal impulses, the inven-V tion covers the use of a cable Morse code transmitter for transmitting a INheatstone-Morse code signal and a special receiver designed to convert the received cable Morse code signal impulses int-o a Wheatstone-Morse code signal.`

rlhe Vlieatstone-Morse code contains approximately 8.5 units per letter and the cable Morse code 3.7- units per letter.

In order to operate Ocean cables With Wheatstone-Morse code so that the output in letters per minute will approximately equal the output obtained with the shorter cable Morse code, it has been proposed to increase the rate of transmission to the necessary extent, but this method is possible only provided the signal thus distorted by rapid transmission is still receivable at the far end of the cable. A system for doing this is disclosed in a British patent. to Judd and Davies, No. 9768 of 1918. In their system they speed up the rate of transmission to twice that of the cable Moise code transmission or to a point where the single waves are so attenuated by the cable that they practically disappear at the receiving end of the cable and are filled in by local'apparatiis.

However, this method of speeding up the transmission has the disadvantage that vthe higher rate of transmission disturbs the 'cable duplex balance. The present invention avoids this undesirable feature while still providing the desired increase in output, by transmitting the Wheatstone-Morse code at the same fundamental rate of frequency as the cable Morse code. Analysis of the nature Aof the Wheatstone-Morse code will show how the desired result may be accomplished Without the accompaniment of the objectionable feature of high speed transmission.

It so happens that thel Wheatstone-Morse code can be arranged into three combinations o f currents, each combination containing two signal-impulse units as follows: For instance, in a letter A, Wheatstone-Morse code, we have the combinations Every other letter can be similarly analyzed into its component parts,

and these will be found to comprise variousarrangements of the two-unit combinations.

W 1th the Judd and Davies method the letter A, is transmitted with eight time units in a given time, and with the system accordin g to the present invention, it is transmitted with four time units in the same given time. In other words, the fundamental rate of transmission Witli the Judd and Davies method is twice that with the method according to the present invention.

To accomplish `the purpose, tlie invention provides that a Wheatstone-Morse code dot shall be produced at the far end of the cable by transmitting a single cable Morse code dot thereover, and a Vheatstone-Morsecode dash 1s produced by transmitting a cable Morse code dash and dot, and, finally, a Wheatstone-Morse code space is produced by transmitting a cable Morsercode space. At the end of the cablea single dot impulse is converted into one positive and one negative impulse, a single dash impulse into two positive impulses and a single space or zero impulse into two negative impulses. In this manner the original Wheatstone-Morse code message is built up at the receiving end of the cable, from the cable Morse code impulses into which it was condensed before' the apparatus forconverti'ng the signals received at the end of the cable into lfVheatstone-'Morse signals.

Fig. 2, Figs. 3a and 3b and Fig. 4 show the yposition of the transmitting relays for a dot signal, a dash signal and a space signal, re-

spectively.

Fig. 5 showsa convers1on key for changing from cable Morse code into IVVheatstone- Morse code, and vice versa. Fig. 6 represents the converted signal (in Wheatstone-Morse code).

Fig. 7 represents the transmitted and received signals (in cable Morse code). f In Fig. 1, the letter A is perforated on the Wheatstone-Morse code tape 10 which is being fed into the usual cable Morse co-de transmitter T. A specialreceiving apparatus R at the other end of the cable Lcooperates end of the cable 15 toearth at 16.v The armatures are spring held against these upper contacts in the non-energized condition of the relays.

An energizing circuit for relay 11 is provided from battery through a pair of contacts 17 and A18, and a similar circuit for relay 12 through a pair of contacts 19 and 20. The pair of contacts 17, 18 are closed when pin 21 penetrates a hole in tape 10 and, upon energization of relay 11 a circuit is closed from positive battery through armature. 13 to cable 15, the armature being held against its lower contact. When, on the other hand,

v pin 22 penetrates a hole in the tape, contacts 19, 20 are closed and a circuit is completed from battery through the closed contacts to the Winding of relay 12, and armature, 14 is moved against its lower Contact. The lower contact for armature 1'4 is connected to negative battery and if relay 11 is not energized, provides a path to cable 15 for negative current flow.

However, if relays 11 and 12 are both energized, armatures 13 and 14 both being held against their lower contacts, the circuit from negative battery to cable 15 is interrupted at the vupper contact of relay 11. Under these conditions the energization of relay 12 is nonelective, while the energization of relay 11 is effective to connect positive battery' to the cable.

The various possible positions of the transmitting relays 11 and 12 are shown in Figs. 2, 3a and 3b, and 4. They will be explained hereinafter in connection with the transmission of the letter-A by suitable perforation of the tape 1,0.

relay 23 controls, by its tongue 24, the opcontact 28, winding of dash relay 26`to. thev other terminal of battery.

The armature 29 of relay 25 through its lower Contact 31 connects battery by way of a conductor 32 to the segments 1, 2, 3 and 4 of a dot ring 33. Segments 1A,'2A, 3A and 4A adjacenttheabove mentioned segments are connected to a common conductor 34, while the rest of the segments 1B, 2B etc. and-1C, 2C etc. are dead segments, being unconnected in the circuit, for a reason which will be apparent from the description of the operation below.

The dot solid ring 35 is connected by way yof conductor 36 to the operating windings 37 and 38 of a dot locking relay 39 and a regenerating relay 40. The brush 41 completes circuit for the dot locking and regenerating relays infy series when itl bridges segment 1 and the dot solid ring 35. When brush 41 passes over onto segment 1A of ring 33 a locking circuit is i completed for the locking and regenerating relays 39 and 40 by way kof contact 43, armature of the dot locking relay, conductor 34, segment 1A, brush 41, dot solid ring 35, conductor 36, windings 37 and 38 of the dot locking and regenerating relays to battery.` This locking circuit is lmaintained until brush 4l passes off segment 1A onto the dead segment 1B. The dot locking and regenerating relays are therefore energized during the passage of the brush over segments 1 and 1A, but this energizing circuit is open while the brush is passing over dead segments 1B and 1C when the energizing circuit is open, biasing winding 46 of relay 40 causes a deflection of the armature of the regenerating relay 40 to its left hand or negative contact 42.

The -dot locking relay is providedalso with a winding 45 through which a spacing current provides a bias to normally maintain the armature of the locking relay in its left hand, non-operative position. A The regenerating relay 4() is also provided with a winding 46 through which a permanent spacing current flows to normally hold the armature of the regenerating relay on its left hand contact 42. The left hand Contact is connected to negative battery and the right hand contact 44 to positive battery, so that dellection of the armature connects one or the other battery to conductor 47. This conducy y .tor may lead to a recorder or the like, or At the receivmg end of the system, a cableto another transmission circuit, if desired.

. local dot relay 26.

The regenerating relay 40 has still a third winding 48, an operating winding which is under the control of the local dash relay 26 and a distributor comprising rings 49 and 50. As in the case of the local dot relay, operation of the local dash relay effects the connection of battery to lower contact 51 of armature 30 and by way of a conductor 52 to the segments 1, 2, 3 and 4 of dash ring 49. However, in this case all the other segments of the ring 1X, 2X etc., 1Y, 2Y, etc., lZ, 2Z, etc., are connected to a common conductor 54, there being no dead.

segments. The dash solid ring 50 is connected by conductor 56 to operating winding 57 of dash locking relay and to the second operating winding 48 of the regenerating relay 40. vA biasing winding 58 of the dash locking relay holds the armature normally against its left hand, non-operative contact. When brush 61 bridges segment 1 of ring 49 and solid ring 50, the dash locking and regenerating relays are energized.v When brush 61 passes onto segment 1X, a locking circuit is completed for relays 59 and 40 from battery and right hand Contact 60 of relay 59, conductors 54 and 56,

windings 57 and 48 back to battery. This locking circuit is maintained during the whole interval that brush 61 is passing over segment 1X, 1Y, 1Z of ring 49. It is apparent, therefore, that operation of local dash relay 26 produces twice as long an energization of the regenerating relay 40 as does operation of the Briefly stated, the receiving apparatus is so designe that operation of the local dot relay causes the regenerating relay to transmit a' positive impulse followed by a negative impulse,.while operation of the local dash relay causes the regenerating relay to transmit a prolonged positive impulse having a duration equal to that of both positive and negative impulses produced by .operation of they local dot relay, or in other words, equal to twice the duration of the positive impulse produced by operation of the dot relay. When neither local relay, dot or dash, is energized the' biasin'g winding of the regenerating relay is effective to cause the transmission vof a negative` spacing impulse.

The operation of the system to transmit a Wlieatstone-Morse code signal will be apparent from the following It is desired to transmit the letter A of the Wheatstone-Morse code, represented in Fig.. 6. Using the conversion key shown in 5, a cable Morse dot or positive impulse represents a dash or negative impulse represents +4-, and zero or spacing current represents the cable Morse code transmitter then becomes that shown in Fig. 7, adot or positive impulse equal in time value to -lfollowed by negative and positive impulses having a time value equal to and, finally, a zeroor spacing impulse having a time value equal to As The signal to be transmitted byl explained above, the Wheatstone-Morse code dash is represented by a cable Morse code dash and dot, so that the Wheatstone-Morse code dash may be treatedas comprising two elements, as represented in Fig. 7.

If the 'signal represented in Fig. 7 is transmitted at the same fundamental rate of frequency as a true cable Morse code signal; it is apparent that in effect, the rate of transmission of the signal, considered as a Wheatstone- Morse code signal, will be doubled.

The tape l having been perforated to represent the letter A according to the principles just explained, the strip is caused to pass through the cable Morse code transmit-- ter T. As indicated in Fig. 1, the dot holes will cause pins 21 and 22 to close both pairs of contacts 17, 18, and 19, 20, and both relays 11 and 12 will be energized, armatures 13 and 14 being moved to their lower contacts (see Fig. 2) However, energization of relay l2 is non-effective, and energizat-ion of relay 11 connect-s positive .battery to the cable. At the receiving end, the tongue 24 of cable relay 23 is deflected to its left hand dot contact and local dot relay 25 is energized. An energizing circuit is established for dot locking relay 39 and regenerating relay 40 by way of segment l of ring 33, and energization is maintained by the action of relay 39 ,in lock,- up over a circuit by way of segment 1A. n Up to this point the regenerating relay has transmitted a positive signal of two segments in length.

Now the brush 41 passes off segment 1A and rides over the dead segments 1B and 1C. The locking circuit is opened and the dot locking relay and regenerative relay are deflected to their left hand contacts by permanent spacing current in windings 45 and 46, during the .time that the brush 41 passes segments 1B and 1C. Up to this time the dot signal has been converted into a positive and negative signal of equal length as shown in Fig. 6 at WW.

Referring again to Fig. 1, the dash holes of the letter A as they pass over the pins 21 and 22, first Will cause the dash pin 22 to piercethe lower dash hole and operatethe dash transmitting relay 12. As shown in Fig. 3, this first part of the Wheatstone dash signal causes the transmission of a negative impulse or cable Morse code dash. t the receiving end, the tongue 24 of cable relay 23 is deflected to the right or dash contact, and the local dash relay 26 is energized. The armature 30 of the dash relay energizes segment 2 of the dash ring via its contact 51 and conductor 52. As the brush 61 of the dash ring passes segment 2 it connects current to the dash solid ring, and by way of conductor 56 causes energization of the dash locking relay.59 and regenerating relay 40. The armatures of these two relays move t0 their right hand contacts.

CTI

- tor 54 from right hand contact and armature When the brush 61 reaches segment 2X it /6 represents the received impulses converted picks up negative current by way of conducof dash locking relay 59 and keeps the dash locking relay and the regenerating relay 40 locked through conductor 56 by -way of the dash solid ring. Since there are no dead segments on the dash ring, the regenerating relay is held over on its rlght hand contact for the length of four segments. Up to this paint, the beginning or first impulse of the eatstone dash signal has been converted into a positive current signal equal in length f to the two units of the Wheatstone dot signal as shown at XX, Figure 6.

Referring again to Fig. 1, upon further -movement of the tape 10, the dot 1pin 21 pie'rc'es the upper dash hole, producing the second part of the Wheatstone dash signal. The dot transmitting rela-y 11 alone is energized, and, as indicated in Fig. 3", its operation causes a positive current to be sent into the cable by way of Ithe armature of relay 11. A t the lreceiving end, the cable relay is deliected to its left or dot contact and in turn operates the local dot relay 25. It has already been shown how a dot signal sent over the cable is converted into a positive and negative signal. The secondfpart of the Wheatstone dash signal, which was received on segment 3 of the dot ring, has been converted into a positive and negative signal as shown at YY, Figure 6.

The space signal of the letter A is sent with the transmitting relays in the position shown in Fig. 4. The space signal has no pin holes and therefore vthe pins 21 and 22 cannot close contacts 17, 18 or 19,20, and neither transmitting relay is energized. As shown in Fig. 4 the transmitting end of the cable is grounded at 16 to transmit the spacing signal.

yAt the receiving end of the cable, the cable relay is deflected neither to left nor right but takes up its position midway, at no-mansland, for the spacing signal. In this case neither the local dot nor local dash relay is operated, and no current is connected to either the dot or dash segments 4.l However, the permanent spacing current in the biasing windings 45, 46, 58 of thelocking relays and regenerating relay is free to operate these three relays to their spacing contacts where they are held for the length' of four segments or until the brushes pass from segments 4 to segments 1.

Up to this point the Wheatstone fspace signal lhaslbeen converted at the receiving end into afnegative current of two unitsj shown f at ZZ, Fig. 6.

The complete cycle of operation for-transmitting and receiving the letter A Wheatinto Wheatstone-Morse code.

It willbe perfectly obviousthat other assignments of the current signs may be made to accomplish the same results. For instance, a dot signal may be transmitted as the dash as and the zero as In this case the circuit arrangement for the transmitting relays and the receiving distributor-segments would be changed -correspondingly to make the necessary conversion at the sending and receiving ends.

The specific arrangement of circuits shown on the drawing is illustrative only as it will be obvious that other specific arrangements may be made wit-hout departing from lthe spirit of the invention. l'

I claim:

1. In a cable system, a cable. Morse code transmitter, a cable, and a receiver comprising a cable relay and `a regenerating relay,

means for operating said regenerating relay to produce positive andfnegative signal im- )ulses in accordance with the Wheatstoneorse code, and means responsive to received cable Morse code impulses in said cable relay for selectively controllingl operation of said regenerating relay.

2. In a telegraph receiving system, a cable 3. In a telegraph receiving system, a re? ceiving relay adapted to respond to current impulses of opposite polarities to close the circuits of either of a pair of local relays, means under the control of the first of said pair of relays for producing double actuation of a regenerating relay to transmit in sequence impulses of opposite polaritiesl and means under the control of the second of said pair of relays for producing a single actuation of said regenerating relay to transmit an impulse of one polarity only, equal in duration to the combined impulses of opposite polarities.

4. In a telegraph receiving system, a receiving relay adapted to respond to current lmpulses of opposite polarities to close the means operative during the non-operative to maintain a circuit through the operatingv condition of said receivin relay to produce a single actuation of sai regenerating `relay to transmit an impulse of the other polarity.

5. In a cable telegraph receiving system, a cable relay having a three position armature responsive to positive, negative and earthing impulses, a regenerative relay, means biasing the relay so as to-transmit an impulse of one polarity, means for actuating said regenerative relay to transmit an im-l pulse of opposite polarity, and means intermediate the cable relay and the regenerative relay for eecting alternate operation of said actuatingand biasingmeans upon receipt by the cable relay of aesignal impulse of one polarity, means for effecting prolonged operation of said actuating means upon receipt of a signal impulse of opposite polarity and means for effecting prolonged operation of said biasing means upon receipt of an earthing impulse.

6. In a cable telegraph receiving system, a regenerating relay having alternate contacts connected to sources of current of opposite polarity, a biasing winding adapted to close one contact to transmit current of one polarity, operating windings under control of separate distributors adapted to close the other contact to transmit current of the other polarity, a cable relay, a pair of local relays and a pair of distributors, means under control of the cable relay and a local relay to establish a circuit from a source of current through the corresponding distributor to an operating winding of the regenerating relay and means under control of the respective distributors for maintaining circuit through lll one operating winding of the regenerative relay for a period twice as long as that during which circuit is maintained through the other operating winding of the regenerative rela 7 .yIn a cable telegraph receiving system, a regenerating relay having alternate contacts connected to sources of current of opposite polarity, a biasing winding adapted to close one contact to transmit current of one polarity, operating windings under control of separate distributors adapted to close the other contact to transmit current of the other polarity, a locking relay for each operating winding of said regenerating relay and means under control of its corresponding distributor to establish an operating circuit and a locking circuit for said locking relay, a cable relay and a pair of local relays, means under control of thecable relay and a local relay to establish a circuit from a. source of current for said vlocking and regenerating relays through the corresponding distributor, segments of said distributor being so arranged that operation of one of said local relays causes' its locking relay ing adapted to cause actuation of the relay 13o winding of the regenerative relay for a period longer than that during which circuit is maintained through the other operating Winding of theregenerative relay upon operationof said other local relay.

8. The method of transmitting a Vheatstone-Morse code signal which comprises condensing said signal into a cable Morse code signal in accordance with a predetermined conversion key, transmitting said condensed signal and automatically expanding the received condensed signal into the original lVheatstone-Morse code signal.

v 9. The method of operating an ocean cable which comprises recording a Wheatstone- Morse code signal, transmitting in accordance with said record a cable Morse code signal whose signal impulses represent the impulses of the Wheatstone signal in accordance with a conversionkey, receiving said cable Morse code signal and automatically reconverting it into a Wheatstone-Morse code signal in accordance withsai'd conversion key.

10. The method of rendering the output of an ocean cable in letters per minute with the lVheatstone-Morse code equal to the output obtainable With the shorter cable Morse code, which comprises condensing a Wheatstone-Morse code signal into a signal having substantially half the number of signal impulses and transmitting the condensed signal at the same fundamental rate of frequency as that of the cable Morse code. C

11. The method of effectively increasing the speed of transmitting telegraphic signals which comprises transmitting'single signal impulses in predetermined order andsequence to represent each a characteristic combination of signal impulses, receiving the single signal impulses and controlling by each im- `pulses the further transmission of its characteristic combination of signal impulses.

12. In a cable system, a cable Morse code transmitter and in combination therewith a tape perforated in accordance with a Wheatstone-Morse code signal.

13. Ina cable system a cable Morse code transmitter comprising apair of relays, and in combination therewith a tape perforated in accordance with the Wheatstone-Morse code cooperating with the elements of the transmitter so that a dotv signal permits siltransmitter and a receiver including a regenerating relay adapted to send positive.

and negative impulses, said regenerating relay comprisingsthree windings, means responsive to an impulse of one polarity from said transmitter to permit energization of one of said windings, means responsive to animpulse of the opposite polarity from said transmitter to permit energization of two of said windings, and means normally biasing said relay by energization of the third Winding.`

16. In a cable system, a cable Morse code 'tion of the relay against the other contact,

a source of current having opposite poles connected to said contacts, means responsive` to a signal impulse of one kind in said receiver to permitv energization of one 'of said other two windings and means responsive to a signal impulse of another kind in said receiver to permit energization in sequence of the second of said other two windings and the biasing winding.

In testimony whereof I affix my signature.

CRESCENT E. NELsoN;

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