US1868680A - Three-unit, three-element code and its application to submarine telegraphy - Google Patents

Description

July 26, 1932. M. H. WQODWARD lLso THREE-UNIT, THREE-ELEMENT CODE AND ITS APPLICATION TO SUBMARINE TELEGRAPHY MARION H. WOODWARD ATTORN EY [BY/LOF l July 26, 1932. M. H. woowARD 1,868,680

THREE-UNIT; THREE-ELEMENT CODE ANI ITS APPLICATION TO SUBMARINE .TELEGRAPHY FIG. Z

nil

INVENTOR MARION H; WOODWARD I'H" VS ATTORN EY H- u y K l BAYC/ I Patented July 26, 1932 UNITED STATES PATENTy OFFECE MARION E. WOODWARD, OF BROOKLYN, NEW' YORK, ASSIGNOE. T0 INTERNATIONAL COMMUNICATIONS LABORATORIESx'y INC., 0F NEW YORK, N. Y., A CORPORATION OF NEW YORK THREE-'UN IT, THREE-ELEMENT CODE AND ITS APPLICATION T0 SUBMARIN E e TELEGRAPHY i Application filed January 6, 1931.

This invention relates to telegraph systems and more particularly to a system for increasing the eiiiciency of transmission over systems comprising cables connected with land lines.

It is well known in the art that the standard two-element five-unit multiplex code such as used in land line telegraphy is not suitable for use over long submarine cables, be-

1 cause of the inefficiency of the multiplex code in comparison with the standard three-element cable code. The output in letters per minute which may be obtained with the standard three-element code (plus, minus or Zero impulses) is in the ratio of to the output which may be obtained by using the multiplex two-element code (plus or minus only) with the same signalling frequency applied to the line.

It is also Well known in the art that the standard cable code is not as suitable for transmission over land lines as is a two-element code because of the extraneous interference induced mto the signalling line from power lines or from other slgnalllng lines.

It :7s usually the practice to operate land lines with a two-element code and to use line currents suiiiciently strong to override the eX- traneous interference. This line interference causes serious trouble in lines operated with the three-unit cable code because during the intervals of the Zero impulses in the code,

'i land line is automatically translated into a Serial No.A 506,879.

three-element three-unit code for transmission over a connecting cable. In such a system a short three-element code may be used on the cable which will be more eicient than the standard three-unit cable code in the ratio of The connecting land line may also be more efhciently operated, because 'asa two-element code will be used, the signalling currents will be less aiiected by extraneous interference. The fact that the six-unit two-element code transmission over the land lines is less efcient in output in letters per minute with the same line frequency than the three-element cable code is not a disadvantage as the operating speed oit' the entire system is limited by the speed of the cable section, which is usually much lower than the operating speed of the connecting land lines.

The six-unit two-element code may be used at the receiving terminal of the system for operating a two position six magnet printer in a manner well known in the art.

One object of this invention is, therefore, to provide means whereby a'six-unit two-element code is automatically translated into a three-unit three-element code for transmission over a cable.' v p A further object is to provide a system which will automaticallytranslate the re-V ceived three-unit three-element code into six-A unt two-element code for retransmission or for operating a six-unit two position printer mechanism.. y

A still further object is to provide means for substituting positive and negative current impulses in the two-element codef Jfor Zero current impulses in the three-element code;`

A still further object is to provide means for reversing the above substitution when in the six-unit two-element and the threeunit three-element codes.

Figure 2 discloses a translator at the transmitting end of a cable.

Figure 3 shows a translator at the receiving end.

Figure 4 shows a typical line signal using the three-unit three-element code and the same signal translated into the two-unit code.

In Fig. 1 is disclosed a series of characters of the three-unit three-element and the sixunit two-element codes. The characters. A, B, C, D and E are in the three-unit code, i. e., each character comprises three impulses of unit length of either positive, negative or zero current. Characters F, G, H, J and K are similar characters in the six-unit code,

i. e., each comprising six impulses of unit length of either positive or negative current. It will be noted that characters A and F and B and G correspond, with the exception that the unit impulses of F and Gr are half the length of the units in A and B. C and .H represent the same character in each code and it will be noted that a positive and negative unit of current has been substituted in H for each unit of zero current in C. J and 'f' ing line and 2O is the outgoing cable. The

line relay is shown at 2 and operates in accordance with the line signals, connecting either positive or negative current to the solid ring of receiving segments M of dis- "I tributor 0, and to the tongue of relay 7. The

alternate receiving segments 5 and 6 are connected to the windings of polar relays 7 and 8 respectively and the tongues of these relays transfer the impulses to the operating windings` 14 and 15 of the dot and dash locking relays 9 and-11 and thence to the segments 12 of the translating ring N of the distributor. Segments 17 of this ring are unlocking segments for energizing the unlocking windings 18 and 19 of the locking relays.

These relays also have biasinnr windings 21 and 22. Locking windings 23 and 24 are also provided which are under the control of their respective relay tongues. These tongues also control the operating windings 25 and 26 of the dot and dash relays 27 and 28, which in. turn control the transmission of impulses to the cable 20.

When a line signal in the six-unit code similar to 29 shown in Fig. 4 is received, the irs't impulse which is positive causes the line relay 2 to operate, moving its tongue to the spacing contact, thereby closing a circuit from positive battery, solid ring, the distributor brush and segment 5 through the winding of relay 7 to negative battery. This relay will move its tongue to the spacing contact where it will remain until an impulse of opposite polarity is-received. The. next impulse which is negative will move the tongue oie relay 2 to the marking contact and close a circuit through segment 6 to positive battery through the winding of relay 8, which will move its tongue to the marking contact. With the tongue of relay 7 on spacing` and the tongue of relay 8 on marking, the circuit for the windings 14 and 15 at relays 9 and 11 is opened, preventing these relays ,trom operating and a zero current impulse is sent out on the cable.

The next unit impulse which is positive again moves the. tongue of relay 2 to the spacing contact and a circuit is closed through the second segment 5 operating relay 7, the tongue of which remains on the spacing contact. The nent pulse being positive, the tongue of relay 2 remains on the spacing Contact and a circuit is closed through the second segment 5 operating relay 8, moving its tongue to the spacing contact.

A circuit is now closed from positive battery on the spacing contact of relay 2 through the tongue and spacing contact of relay 7, spacing contact and tongue of relay 8, windings 14 and. 15 of relays 9 and 11, segment 12 and solid ring to negative battery. Since relays 9 and 11 are polar relays and the windings 14 and 15 are oppositely poled, the tongue of relay 9 will move to the marking Contact .and that of relay 11 to the spacing contact, closing a circuit from positive battery, marking contact and tongue of relay 9, windings 25 and 26 of relays 27 and 28 spacing contact and tongue ot relay 11 to negative battery, thereby moving the tongue of relay 28 to its spacing Contact and that of relay 27 to its marking contact, and thereby closing a circuit from positive battery, tongue and spacing contact of relay 28, to cable 20, through ground, tongue and marking contact of relay 27 to negative battery thus transmitting a positive impulse to the cable 20. Simultaneous with the closing of the circuit for windings 25 and 26, a second circuit was closed through the locking' windings 23 and 24 of relays 9 and 11, holding these relays operated even after the brushes leave segment 12. Positive battery is connected to the cable until the brushes reach segments 17 when unlocking windings 18 and 19 are energized over a circuit from negative battery solid ring, segment 17, winding 13 and 19 to positive battery. The current in these windings overcomes the effect of the locking windings 23 and 24 and together with the biasing windings 21 and `22 move the tongues of relays 9 and 11 to their spacing contacts, thereby releasing relays27 and 23 whose biasing windings move their respective tongues to the spacing contacts and remove positive batteryfrom the cable.

The next two impulses being negative, the tongues of relays 7 and 8 both move to the marking contacts and the tongue of relay 9 will remain on its spacing contactw hile that of relay 11 will move to its markingcontact. The tongue at relay 28 will now move to the marking contact while that of relay 27 remains on its spacing contact and4 negative battery will be connected to the cable until the distributor brush reaches the next unlocking segment 17.

1t will be noted from the above that when consecutive pulses of the same polarity are received, impulses of the same polarity are transmitted over the cable and when consecutive pulses of alternating polarity are received, a zero current pulse is transmitted. The resulting signal is shown at 30 (Fig. 4).

In Fig. 3 is shown the circuit for retranslating three-unit three-element signals into six-unit two-element pulses for operating a two position printer 40. The retranslation of the above designated signal 30 into sir:- unit two-element pulses will be used as an illustration.

The signals are received from the cable 2() by the line relays 31 and 32 which control the operating circuits of the locking relays 33 and 34 through the medium of the regenerating rings R of the distributor 35. Normally the armatures or tongues of the line relays 31 and 32 are held against the spacing contacts, by reason of the energization of the biasing' windings b, as shown. Relays 33 and 34 in turn control the operation of the printer relay 36 which has a second operating winding 37 under control of the translating rings T. The tongue of relay 36 controls a circuit through the selecting rings S for operating three storing relays 41, 42 and 43 which in turn operate the first three printing magnets 44, 45 and 46 and also controls the last three printing magnets 47, 43 and 49. The printer operating magnet 50 is under the control of the local operating rings L.

For the first two impulses oi signal 30, which are Zero current pulses, the line relays 31 and 32 and the locking relays 33 and 34 remain unoperated. The zero current oiE the three unit code must be translated into alternate impulses of positive and negative current. This is vdone by the alternate segments 33 and 39 of the translating ring T iirst connecting negative and then positive current through thewinding 37 of relay 36, causing its tongue to move first to its spacing contact and then to its marking contact.

1/Vhen the tongue rests on the spacing contact, a circuit is closed from positive battery through the solid ring and brush of rings S, segment winding of relay 41 to negative battery. This circuit causes the tongue of relay 41 to move to its marking contact, thereby establishino a circuit from positive battery through the winding of printer magnet 44, to segment 59 of rings L. As the brush of the distributor has not reached segment 59 at this time, magnet 44 will not operate. Due to the fact that relays 41, 42 and 43 are polarized relays their tongues will remain on their marking contacts until an iinpulse of opposite polarity causes the tongue to move to spacing. This maintains the circuit for relay 44, and 46 until the brush associated with rings L reaches segment 59.

The positive impulses from segment 39 of rings T above referred to will now cause relay 36 to move its tongue to the marking contact, closing a. circuit for relay 42 from negative battery through segment 53 to positive battery thereby maintaining the tongue of this relay on its spacing contact and no circuit will be closed for the operation of magnet 45.

The next impulse received over the cable according to signal 30 is a positive pulse which will cause relay 31 to move its tongue to marking and relay 32 to move its tongue to spacing', thereby closing a circuit `from positive battery through the operating windings 60 and 61 of relays 33 and 34, segment 63 and solid ring of rings R to negative battery. This causes the tongue of relay 33 to move to its marking contact and the tongue of relay 34 to remain on its contact thereby closing a circuit from positive battery through the tongue and marking contact of relay 33, winding 64 of relay 36, spacing contact and tongue of relay 34 to negative battery, thereby causing the tongue of relay 36 to move to the spacing Contact and close a circuit rom positive battery through the solid ring and segment 54 of rings S for operating relay 43. This causes the tongue of relay 43 to move to its marking contact and establish the circuit for operating magnet 46.

The second part of the positive impulse of the signal holds the relays 31, 32, 33, 34 and 36 in their same positions, thereby closing a circuit through solid ring and segment 55 of rings S for opera-ting magnet 47.

The third portion of the incoming signal which is negative causes relay 31 to move its tongue to the spacing contact and causes relay 32 to move its tongue to the marking contact thereby closing a circuit from negative battery through the operating windings 60 and 61 of relays 33 and 34, moving the tongue of relay 34 to marking and holding llU the tongue of relay 83 on spacing. A circuit is now closed from positive battery through the marking contact and tongue of relay 34 through winding 64, spacing contact and tongue of relay 33 tol negative battery, causing the tongue of relay 36 to move to its marking Contact. As negative battery is connected to both the marking contact of relay 36 and to printer magnet 48, no circuit will be established and thus magnet 48 will not be operated.

In the meantime the distributor brushes have reached segment 59 orp rings L, thereby completing the operating circuit for magnet 44 and 46 as described above.

The neXt pulse which is again negative `vill hold the tongues of relays 31, 32, 33, 34 and 36 on the contacts as described above and magnet 49 will not be operated. When the brush reaches segment 58 of the operating rings L the printer magnet 50 will operate in a well-known manner.

What is claimed is:

l. Ina telegraph system, the method of translating from a three-unit three-element code of positive, negative and Zero current impulses to a six-unit two-element code of positive and negative impulses by substituting a positive and negative current impulse for each Zero currentv impulse.

2. In a telegraph system, the method of translating from a six-unit two-element cooleY of positive and negative current impulse to a three-unit element code of positive, negative and zero impulses by substituting a Zero current impulse for a positive and negative current impulse.

3. In a telegraph system, a pair of stations, a line connecting said stations, means at said first station for translating a six-unit twoelement code into a three-unit three-element code of retransmission over said line, and means at said second station for retranslating said three-element code into said two element code.

4. In a telegraph system, a signalling line using a two-element code of positive and negative current impulses, a second line connected to said first line and using a three-element code of positive, negative and zero current impulses, and means at the junction point of said lines for substituting for the alternating impulses of positive and negative current of said first line zero current impulses for transmission of said second line. j

5. In a telegraph system, a long signalling line using a three-element code of positive, negative and zero current impulses, a shorter line connected to said first line using a twoelement code of positive and negative current impulses, and means at the end of said line for substituting short alternating impulses of positive and negative current for said Zero current impulses.

6. In a telegraph system, a pair of stations,

a long line connecting said stations, a translator at one of said stations for translating a three-element code of positive, negative and zero impulses into a two-element code of positive and negative impulses, and means in said translator for substituting short impulses of alternate polarity for said zero ourrent impulses.

7. In a telegraph system, a pair of stations, a long line connecting said stations, a translator at one of said stations for translating a two-element code of positive and negative impulses into a three-element code of positive, negative and zero current, and means in said translator for substituting Zero current for impulses of alternate polarity.

8. In a telegraph system, a translator for translating two-element code into three-element code, a line relay controlling the operation oi a pair of control relays, a pair ot regenerating relays under the joint control of said control relays and a commutator having positive and negative battery connected thereto, a pair of transmitting relays controlled by said regenerating relays and adapted to transmit zero current when consecutive positive and negative impulses are received by said line relay.

9. In a telegraph system a translator for translating two-element code int-o three-element code, a line relay cont-rolling the operation of a pair of control relays through alternate segments oi a commutator, a pair of regenerating relays under the joint control of said control relays and a commutator having positive and negative battery connected thereto, said control relays having their contacts interconnected to supply current of different potential, a pair of transmitting relays under control of said current and being adapted to transmit Zero current when consecutive positive and negative impulses are received by said line relay.

l0. In a telegraph system, a translator for translating three-element code into two-element code, a pair of line relays, a pair of locking relays operatively controlled by said line relays, a'single regenerating relay under the joint control of said locking relays and of a commutator having positive and negative battery connected to alternate segments thereof, said regenerating relay being adapted to transmit short positive `and negative impulses when zero current impulses are received by said line rela-ys.

ll. In a telegraph system a translator for translating three-element code into two-element code, a pair of line relays, a pair or" locking relays having c-peratin g windings under control of said line relays and locking windings under control of a commutator, a regenerating relay under the con trol of said locking relays and a second commutator having positive and negative battery connected thereto, said regenerating etAV ibo

izo

relay controlling a plurality of printing mag nets through a third commutator and a series of control relays.

l2. In a telegraph system a line using sixunit two-element code, a cable using threeunit three-element code, a line relay in said line controlling the operation of a pair of control relays, a pair of regenerating relays under the joint control ot' said control relays and a commutator, a pair oi' transmitting relays controlled by said regenerating relays and adapted to transmit three-unit code to said cable, a pair of cable relays, a pair of locking relays jointly controlled by said cable relays and a commutator, and a regenerating relay jointly controlled by said control relays and a second commutator having positive and negative battery connected to alternate segments thereof, said regenerating relay operating a plurality of printing magnets in accordance with the translated three-unit code received by said cable relays.

In Witness whereof, I hereunto subscribe my naine this 5th day of January, 1931.

MARION H. WOODWARD.

Images