US2104273A - Start-stop regenerative repeater - Google Patents

Description

Jam-4,1938. L. M. POTTS 3 START-STOP REGENERATIVE REPEATER I Filed Feb. 16, 1934 INVENTOR LOU/5 M.

' POTTJ ATTO EY Patented Jan. 4, 1938 SPATENT .QFFICE START-STOP REGENERAT'IVE REPEATER Louis M. Fctts, Evanston, 111., assignor to Tele- Qorporation, Chicago, 111., a corporation or" Bela-Ware February 16, 1934, Serial No. 711,479

30 Claims;

This invention pertains to telegraphy and more particularly to the automatic transmission of telegraphic signal codes from one line section to another.

In telegraph systems using comparatively long signal impulses, relay repeaters which renew the current value in each impulse but which may modify the length of the impulses slightly have been found satisfactory for some telegraphic purposes, but in systems where transmission, is effected at high speeds, it becomes necessary to preserve the relative lengths of signal impulses well as to renew the current strength thereof. Accordingly, an object of this invention is to provide a repeater for start-stop systems of automatic telegraphy in which received signal impulses are reproduced and retransmitted in renewed strength and in faithful reproduction of their relative time value, thereby producing a complete regeneration of the signal impulses and signal conditions as originally created and transmitted.

Further features are to repeat and regenerate the start and stop control impulses as, well as the intelligence impulses and to provide a startstop regenerative repeater in which relative lengths of retransmitted impulses are determined locally by mechanical means, but in which an electrical characteristic of each repeated impulse is determined by a received signal impulse to which the retransmitted impulse corresponds.

These and other objects are attained by utilizing the principles of a speed regulated motor shaft and start-stop control for synchronizing the receiving and retransmitting functions taken in connection with cam controlled retransmitting contacts which, by start-stop principles, are kept in synchronism with the incoming signal impulses.

The system of this invention comprises a regenerative repeater which is associated with a circuit arrangement to repeat in but one direction, but it is to be understood that the apparatus is such that it may be used in circuit systems in which repeating in both directions upon a single telegraphic line system may be conducted. Apparatus achieving such an object is disclosed in copending application Serial No. 755,253, filed Nov. 30, 1934. a

A The apparatus of the present invention comprises astart-stop cam or set of cams with a driving motor and with a clutch which permits the cams to be normally stopped but in condition to be started in response to a received signal.

In response to a received starting impulse, the

cams start and continue in motion for a complete code cycle of operation, then come to rest in readiness for the next cycle. Retransmitting contact points are arranged to be dually controlled, first by the cams to determine the length of every signal impulse and second, by means responsive to received signal impulses to determine the electrical characteristic of each retrans mitted impulse according to the received impulse which it represents, the start impulse and stop impulse being repeated as well as the intelligence impulses of each code group of impulses.

A better understanding of the invention may be had from the following description, taken in connection with the accompanying drawing, 15 wherein :Fig. 1 shows a telegraphic system comprising two line circuits associated in signal repeating relation by a repeater of preferred type according to the present invention;

Fig. 2 shows an alternative type of repeater;

Fig. 3 shows a detail of the repeater of Fig. 2;

' Fig. 4 shows a modification of the repeater of Figs. 2 and 3;

Fig. 5 shows an alternative type of repeater;

Fig. 6 shows a detail of the repeater of 5;

Fig. 7 shows a modification of the repeater of Fig. 5; and- Fig. 8 shows a starting latch.

Referring to Fig. 1, a controlling line circuit includes battery I, receiving magnet 2', line wire 3, remote transmitter 4, and ground 5, and a controlled line circuit includes battery ti, resistor 'I, contact 8, contact 9, line wire H3, receiver magnet II; and ground I2. Magnet 2 has an armature i5 pivoted at I6 with retractile spring I'I having selective abutments I8, I9, and with a striker 20 for controlling a starting mechanism, not shown, for starting a cam sleeve 2!. The starting mechanism may be of the type shown in Patent No. 1,783,382, issued to H. L. Krum and comprising in part a friction clutch and a clutch releasing latch, although any other type of clutch and latch suitable for printing telegraph equipment may be used. In Fig. 8, upon release of .45 armature I5, striker 2|] pushes pin H5, which rotates levers IIS and II! to release a starting latch IIB whose tooth II9 releases arm ill! fixed upon friction-urged cam sleeve 2|. Cam sleeve 2i is associated through a friction clutch with a constantly operating power shaft 26, and carries a multiple cam 21 having lobes which consecutively engage a cam follower 28 pivoted at 29 with retractile spring 30. Follower 28 has also a-socket arm 33 which surrounds a disc like head 34 of T-member 35 which has abutment extensions 36, 3? and a slotted arm 38. Within the slotted arm 38 is contained an operating pin 42' fixed upon lever 43, pivoted at 44, and having jockey 45. Striker 46 secured to member 35 engages contact 41 to move it into engagement with contact 9 normally in engagement with contact 8.

In operation, the structure shown in Fig. 1 normally has magnet 2 energized, its controlling circuit being normally closed at transmitter 4 as shown, with its armature in operated position as shown. Signal impulses are transmitted over line 3 in code groups of seven impulses per group, each group beginning with a spacing or open impulse and terminating with a marking or current impulse. The first signal, spacing, of a re ceived code of signals will deenergize magnet 2 and release armature l5, thus causing striker 20 to start cam sleeve 2! and also will position abutment l9 in apposition with abutment 36. Immediately cam 21 starts revolving and lobe 50 operates follower 28 to operate T-member 35, which causes abutment 36 to engage abutment IS and which rotates member 35 upon abutment l9 as a fulcrum, so that slotted arm 38 acts through pin 42 to rotate lever 43 which is locked in its operated position by jockey 45 and which, in its operated position, operates contact 4'! to engage contact 9 and to lift contact 9 away from contact 8, thus opening controlled line circuit I0 and repeating a spacing signal of nocurrent in controlled line circuit In in response to a similar spacing signal in controlling line circuit 3.

The above described action comprises repeating the starting signal impulse of a code, following which. five intelligence impulses and a stop impulse are repeated by cam lobes 5| to 56 inclusive in cooperation with armature I5 controlled by magnet 2. As each lobe 50 to 55 inclusive opcrates follower 28, the member 35 is moved to engage either abutment IE or abutment l8 and therefore operates lever 43 to or from its marking position as shown accordingly as a received signal impulse is-marking or spacing in nature. A signal in controlling line circuit 3, whether marking or spacing, determines the condition of magnet 2, whether energized 'or deenergized, which determines the position of armature l5, whether attracted for marking or released for spacing, which determines the efiectively positioned one of abutments l8, [9, whether [8 for marking or H] for spacing, after which the retransmitted impulse will be determined in feature of its duration and in feature of its elapsed time relation to the starting impulse wholly by the mechanical action of the cam 2'! which is driven by a local motor running at a constant speed, and the retransmitted impulses thus are given relative lengths determined by local mechanical means at the repeating apparatus regardless of the relative length of the marking and spacing signals as received by magnet 2 over line circuit 3.

In an apparatus for polar working, magnet 2 may be of polar type and contact 41 may be con-' nected through a resistor as 1 to a battery as 6, but of reversed polarity, the contact 9 then cooperating with contacts 8 and 41 to produce polar reversals of current in line IE as the contacts are operated by lever 43.

An alternative mechanical form of the invention is shown in Figs. 2 and 3. For a more comprehensive explanation of the mechanical details of this structure, reference may be had to Patent No. 1,821,110 issued to S. Morton et al. September l, l931,'and to Figs. 1 and 3 thereof particularly. Cam barrel 5| symbolizes a complete printer such as disclosed in the patent to Morton et al. and when taken with the addition of signal lever 52 and multiple lobe earns 53 and 54' for marking and spacing signals respectively, Fig. 3 discloses a combination printer and start-stop regenerative repeater. Cam barrel 5| has stop arm 55' which engages a fixed stop dog 56 and a signal lever 52', corresponding to signal lever 43' in Fig. l','has jockey 51 corresponding to jockey 45 in Fig. 1, and has striker 58 corresponding to striker 46 in Fig. 1 whereby contacts 41', 9', and 8' are operated as in Fig. 1.

In the Morton et al. printer, the cam barrel 5! has sixlp-airs oi cams 50' which control six selector levers in accordance with six received intelligence impulses, operating the selector levers sequentially to register each impulse as the intelligence impulses are received, after which a transfer action occurs which transfers the six registrations simultaneously to the selectorand printing mechanism'of the printer. Added to the Morton et al. mechanism is the special signal lever 52' for repeating the received impulses. The special lever 52? is coaxial with the six regular selector levers of the printer, and operates to marking and to spacing positions in a manner similar to the operation of the printer se- 7 lector levers but operates for every impulse of the entire signal including start and stop impulses. With every movement of the special signal lever 52 it changes the contactual relations of the contacts 8, 9', and 41' and causes them to transmit to the controlled line section I0 a signal impulse corresponding to the instant signal impulse in the controlling line section. The special signal lever 52' is not associated with the transfer mechanism which cooperates with the six signal levers of the printers printing mechanism, so that the transfer action and subsequent actions of the printer are not effective upon the retransmission mechanism.

V In operatic-n, as a repeater, the structure shown in Figs; 2 and 3 normally has cam barrel 5! in position toward the left as shown, it being held in that position under control of an energized line magnet corresponding to magnet 2 in line circuit 3 of Fig. 1. Signal impulses are transmitted over line 3 in code groups of seven impulses per group, each group beginning with a spacing or open impulse and terminating with a marking or current impulse. The first signal, spacing, of a received code of signals will release cam barrel 5i, as will be understood from the Morton'et al. patent. The cam barrel will move toward the right to clear stop dog. 56, will move marking cam 53 away from upper cam follower 59 of lever 52', move spacing cam 54' into position'to engagelower cam follower 60 of lever 52,

and will begin a revolution at regulated speed. Immediately thereafter, a lobe of cam 54' engages follower BD and moves lever 52' into its alternative position and operates striker 58 and contacts 41' and 9, thereby disengaging contact 6 from contact 8 and opening controlled line circuit l0 and repeating a spacing signal impulse of no-current in controlled line circuit ID in response to a similar spacing signal impulse in controlling line circuit 3. The above described action comprises repeating a starting signal impulse of a code, following which five intelligence impulses and a stop impulse are repeated by cam barrel 5! in cooperation with contacts 41, 9,

and 8'. As each impulse, whether marking or spacing, operates cam barrel 5! to left or to right accordingly as the controlling impulse is marking or spacing, lever 52 is brought under control of cam 53 or 54 accordingly as the impulse is marking or spacing, and a lobe of the then effective cam 53 or 54 determines the position of lever 52, which in turn determines the operation of contacts 41', 9', and 8. The time duration and electrical nature of a retransmitted impulse, and its time relation to its starting impulse, will be determined wholly by the mechanical action of cam barrel 5! which is driven by a local motor running at a constant speed, while the electrical nature of each retransmitted impulse will be determined by the left or right position of cam barrel 5i as determined in turn by the marking or spacing nature of a signaling impulse of the instant electrical signal in the controlling line.

In Fig. 4 is shown a development of cams 53 and 54 shown in normal form in Figs. 2 and 3. A modification is shown in cam lobes 53A and 54A in that the two said lobes are extended in axial dimension in such manner that lobe 54A always engages cam follower 60 to operate signal lever 52 whether cam barrel 5!! is positioned to right or to left by a received signal, and lobe 53A always engages cam follower 59 to operate signal lever 52 whether cam barrel 50 is positioned to right or to left. Thus, start and stop signals of proper timing and of proper electrical characteristic are sent to line H) independently of control by any received signal, and only the intelligence impulses are repeated under direct control of received signals.

A further mechanical type of the invention is shown in Fig. 5 with a detail in Fig. 6. For a more comprehensive explanation of this structure, reference may be had to Patent No. 1,370, 669, issued to L. M. Potts, March 8, 1921, and to Fig. 18 thereof particularly. In the Potts patent is disclosed a method of operating a receiving device in which a detector lever is supported loosely at both ends and is spring tensioned near one end and between the supports. A can: applies power to a median point of the lever and the non-tensioned end ope-rates if the lever is unrestrained, but should the non-tensioned end be restrained as a result of a line signal, then the tensioned end of the lever will respond to the cam. Thus a spacing signal impulse of no-current in the line circuit will restrain the nontensioned end of the detector lever and cause the cam to operate the tensioned end of the detector lever to operate in turn a signal lever to register a space signal, while a marking signal impulse of current in the line circuit will not restrain the detector lever and will permit the cam to operate the non-tensioned end of the detector lever to operate in turn a signal lever to register or indicate a marking signal impulse.

In the structure of Figs. 5 and 6, illustrated in two sectional views in exploded arrangement of upper and lower views a continuously operating motor power shaft BI is connected through a friction clutch with a single cam sleeve 62 which sleeve is integral with one cam 63 in the upper view and with five pairs of mated cams as and 65 in the lower view, the eleven cams cooperating spring 59 against stop l0 and pivotal stop H with cam follower l2 projecting into the path of lobes l3 and M of cam 63. Striker 17 on cam follower lever 68 may engage lug 18 on signal lever 15] pivoted at 8% to rotate lever 'Hl clockwise, and striker 8! on cam follower lever 68 may engage lug 82 on signal lever 19 to rotate lever 19 counterclockwise. Signal lever 19 is normally restrained by jockey 83 and operates contacts 84. Magnet 85 shown in the lower view has an armature E36 which is pivoted at B? and which has retractile spring 88 and which has also an operating edge 90 shown in both upper and lower views which normally is out of the path of ends ill of lever 63 in the upper view and Q 5 in the lower view, and normally is held in that position by energization of magnet 85 corresponding to magnet 2 of Fig. l. Armature 35 has also a cam-starting striker 92 corresponding to striker Zll in Fi 1.

Cam 64 cooperates with a cam follower lever 95 which is held yieldingly by spring 96 against stop H3 and pivotal stop 1! with cam follower 91 projecting into the path of cam 64. Striker as on cam follower lever 95 may engage lug 99 on signal lever [02, pivoted at 88, to rotate lever 32 clockwise.

Gain 65 cooperates with a cam follower lever lot which is held yieldingly by a spring similar to 9 3 against stops 1B and ii with a cam follower similar to an projecting into the path of cam 55.

Striker led on cam follower lever I63 may engage lug 595 on signal lever N52 to rotate lever H12 counterclockwise. Lever I03 is largely obscured by lever 95 in Fig. 5. The contour of lever IDS is similar to the contour of lever 95 except that lever H33 terminates at I06 and has neither operating end 9! nor striker 98 for rotating lever sea clockwise, but has instead striker lil l for rotating lever lllZ counterclockwise. Both levers 95 and it? are guided by comb Hl'l, Fig. 5, in which lever 95 moves freely in a deep notch and in which lever M13 is restrained by a shallow notch against movement in response tocam 65, Fig. 5.

Signal lever 12 operates contacts Hi8, there being five pairs of cams 64, 65, five pairs of cam follower levers 95, N33, five signal levers H32, and

five pairs of contacts H28 all corresponding to five intelligence signal impulses in a received code of impulses, additional similar equipment being provided when longer codes are served. Successive pairs of cams $4, $5 are spaced at successive angles upon cam sleeve 62. A controlled line circuit extends from ground Hi through battery H2 and resistor H3, then through all contacts I08 and 84 in parallel to line wire H4.

In operation generally, in the structure of Fig. 5, cam lobe 73 operates lever 19 to open contacts 84 to repeat a starting signal of spacing or open electrical nature, followed by successive operation of five levers M2 to operate five pairs of In operation specifically, when a starting signal impulse of open circuit condition deenergizes magnet 85, armature 86 is operated by spring 88 and striker 92 operates a clutch (not shown) to start cam sleeve 62 and its earns 63, i5 5, and 65. Armature 86 being deenergized, operating edge 90 now is positioned in the path of all ends 9| and cam lobe 13 engages follower l2 and operates lever 68 which being restrained at end 9| by edge 90 rotates upon edge 90 as a fulcrum and causes spring 69 to yield, thus causing striker 8| to operate lever 19 which rotates upon its pivot and operates contacts 84 to open retransmission circuit IE4. This constitutes the repeating of the starting impulse of a code now being received. At a time instant thereafter, during a median part of the first intelligence impulse signal, signal receiving magnet 85 will be energized or deenergized according to the marking or spacing nature of the first intelligence signalimpulse, armature 86 will be attracted or unattracted according to the marking or spacing nature of the impulse, edge 90 will be out of or in the path of end 9| of the first lever according to the marking or spacing nature of the impulse, first cam 64 will engage first cam follower 91 and willoperate end 9! on H as a fulcrum or will operate end I20 on Silas a fulcrum according to the marking or spacing nature of the impulse, as a,

result of which the first lever I02 will be moved clockwise by engagement of striker 98 with lug 99 or will not be moved according to the marking or spacing nature of the impulse, by which the first pair of contacts I98 will be closed or will remain open according to the marking or spacing nature of the first intelligence signal impulse, thus repeating in the controlled circuit I I6 the instant marking or spacing signal impulse of a controlling circuit in which magnet 85 is included. Thereafter at a similar instant of the second intelligence signal impulse, cam 65 invariably will engage cam follower (not shown) of lever I83 and invariably will operate striker we to operate lever I02 counterclockwise to permit the first contacts IRS to open, this restoration of the first pair of contacts occurring simultaneously with the operation of the second lever 102 by the cam 64 of the second pair of cams, thus terminating the first retransmit-ted intelligence impulse and initiating the retransmission of the second 7 intelligence signal impulse. In like manner the third, fourth, and fifth intelligence I signal impulses are repeated, and as the fifth cam 55 terminates the fifth retransmitted intelligence signal impulse, cam lobe 14 operates lever 68 for retransmission of the stop signal impulse which always is of marking nature with magnet 85 energized, with armature 8 5 attracted, and with edge 90 out of the path of end 9| of lever 68 and striker Tl invariably is operated to engage lug 73 to rotate lever 79 to cause contacts 84 to close, thus retransmitting the stop signal. In the transmission of the code as described, each instant of beginning and ending ofevery retransmitted signal impulse has been timed by local mechanism driven by a local speed regulated motor, and every impulse including starting and stopping impulses have been governed in electrical nature by an electrical signal instantly existing in a controlling circuit.

By positioning each cam 65 in an angular position between its preceding cam 5-! and its following cam 64, there will be attained the effect of opening the controlled circuit H4 after each and every intelligence impulse and therefore between consecutive impulses when such form of signal transmission is desired.

A modification of the structure of Fig. 5 is shown in Fig. 7 wherein all contacts I08 and all levers 95, I03, I02, are omitted and all cams 65 are omitted, the cams 64 being transferred to tacts 34 will be closed or will be permitted to open according to the natureof the received intelligence impulse. In each retransmitting operation, the time is controlled by local rnotor and cam and the nature of the retransmitted impulse is controlled by the instant received signal impulses in the controlling line circuit.

Throughout the several species and modifications in which the present invention has been illustrated for purpose of complete description, the following generic features will be noted. mechanical design for cam starting, cam driving, and cam controlling has been taken in conformity to designs of selectors for receiving printers, and in each species a design shown suitable for attachment to a receiving printer to form a combined receiver-printer-repeater. In each species the retransmission is effected by power. driven contacts, the control of the received signal being exercised in the function of determining whether attaining a condition for utilizing contacts of considerable mechanical strength, of firm contact pressure, and of great reliability. Designs are shown in which but a single contact tongue is used, thereby achieving great simplicity.

Reference is made to application Serial No. 712/51 to Walter J. Zenner, filed February 23, 1934 which discloses one form of a start-stop regenerative repeater,

. What is claimed is:

1. In a telegraphic repeating device, a contact member for retransmitting a received signal, an armature controlled by a received signal, and a timing. cam started into operation under the control of said armature fortlmlng retransmitted signals and cooperating with said armature for operating said contact member in accordance with the instant position of said armature to control the character of the retransmitted signals.

2. In atelegraphic repea device, a contact member for retransmitting received signals, an element controlled by successive received signals, a locking member restraining 1 contact member in its set position, and a tim 1 cooperating with said element operating said contact member repeatedly to ccntroi t .ng of successive retransmitted signals determined by said element.

3. In a telegraphic repeating device for equal length signal intervals, a contact member for retransmitting received signals, an armature controlled by successive received signals, a locking member restraining said contact member, a multiple lobed timing cam, a latch operable by said armature to start said timing cam at the beginning of'each signal interval, and a cam follower for said timing cam releasing said contact member successively during each cycle of rotation of said cam to control timing of successive retransmitted signals during each signal interval.

4. In a telegraph device, a single contact member for retransmitting a received signal, an element controlled by a received signal, a cam controlled by said element, and means dually controlled by said cam and said element and oper- The ating said contact member at a predetermined instant to retransmit an instantly received signal.

' 5. In a telegraphic repeating device, a contact member for retransmitting received signals, an armature controlled by successive received signals, a start-stop multiple lobed cam, and means dually controlled by said cam and by said armature and operating said contact member repeatedly at predetermined inst-ants to retransmit directly a group of received signal impulses during a single cycle of said cam. V

6. In a telegraphic repeating device, a contact member for retransmitting received signals, an armature controlled by successive received signals, a multiple lobed cam, means dually con trolled by said cam and by said armature and operating said contact member at predetermined instants to retransmit a plurality of received signal impulses during each cycle of said cam, and a latch operable by said armature in response to a received timing signal to start said cam.

'7. In a telegraphic repeating device, an armature controlled by a received signal, a contact member, and cam operated mechanism started under control of said armature and cooperating with said armature for operating said contact member to retransmit said received signal under instant control of said armature.

8. In a telegraphic repeating device, an armature controlled by successive received signals, a single contact member, cam operated mechanism started by said armature and adapted to operate said contact mechanism at successive instants of beginning of a plurality of signal time intervals, and means associated with said armature for controlling said cam operated mechanism in accordance with the electrical nature of an instantly received signal, a

9. In a telegraph repeater, a signal timing device. comprising a multiple lobed timing cam, means for starting said cam upon receipt of a received timing signal, means for retransmitting signals under control of said cam at each instant of beginning of time intervals of a plurality of signals, and means controlled by successively received signals at the instant of beginning of retransmission of each received signal and controlling said retransmitting means to' determine the electrical nature of each retransmitted signal.

10. In a regenerative repeater, a retransmitting contact, a motor driven cam to operate said retransmitting contact to retransmit start and stop signals invariably at fixed time intervals after receipt of a starting signal, and means under control of other signals to render sai-d cam effective to operate said retransmitting contact variably at other fixed time internals and in ac-.

cordance with received signals.

11. In a regenerative repeater, a transmitting contact, a motor driven cam barrel to operate said contact invariably to transmit start and ly by said armature, and a second means to retransmit said code signals controlled jointly by the rotary member and the position of said armature at the instant of beginning of repeating each signal impulse.

13. In a regenerative repeater, a magnet controlled by received signals, an armature for said magnet, a motor driven rotatable cam controlled to start into rotation by said magnet, and a retransmitting contact whose position in successive intervals of time is determined by said armature and the time of beginning and end of the irltervals is determined by said rotatable cam.

14. In a regenerative repeater, a magnet controlled by received signals, an armature for said magnet, a motor driven rotatable cam controlled to start into rotation by said magnet, and a retransmitting contact whose position in succesretransmitting intervals of time is determined by said armature and the length of the retransmitting intervals is determined by said rotatable cam.

15. In a telegraph system, means controlled by a received line signal, a contact element adapted to transmit regenerated impulses, a start-stop rotary member, means to lock the contact element in either marking or spacing position, and means to change the contact element from one position to the other under the. dual control of said rotary member and said first mentioned means Within intervals of control which are small in comparison with the length of the said regenerated impulses.

15. Telegraphic apparatus including a member having motion in lineal and rotary directions, power driven means to move said member, yielding means opposing the motion of said member in rotary direction, selectively operated means controlled by received signals to oppose the. motion of said member in lineal direction to cause it to move in rotary direction against said yielding means,,and a retransmitting contact operable by said member.

1'7. Telegraphic apparatus controlled by received signals, including a member having motion in first and second directions, power driven means to move said member in first direction and operating for each received signal independently of the electrical character of the received signal, yielding means opposing motion of said member in second direction, selectively operated means to oppose motion of said member in first direction to cause it to move in second direction against said yielding means, and a signal retransmitting contact operable by said member.

18. In a regenerative telegraphic repeater, a multiple cam, a signal controlled member, a se ries of contacts closable under control of said cam in variable sequence according to control by said signal controlled member, and invariable means to open the closed contacts ofsaid series in sequence.

19. In a telegraph repeater system for retransmitting signals each composed of a start impulse, a rest impulse, and a plurality of variable code impulses, a start-stop cam, an armature controlled by received signals, a retransmitting contact, and means controlled by said cam and said armature jointly to operate said contact to transmit corresponding signals under the control of said original signals, said armature exercising control for a small part only of each elementary impulse.

20. In a start-stop telegraph repeating system, start-stop means to transmit telegraph signals each composed of a start impulse, a rest impulse, and a group of code impulses, a retransmitter, means to bring said retransmitter under control of said several impulses for a period in each impulse short in comparison with the duration of an impulse and substantially in the middle of each impulse and thereby retransmit a duplication of the original signal lagging substantially one-half of an impulse behind the received impulses, and locking means for said retransmitter effective between said periods.

21. In a telegraph system adapted for the transmission of signals each composed of an invariable start pulse and a plurality of variable code impulses, a cam member, a constantly rotating shaft, means to start said cam member by coupling said cam member to said shaft for each start impulse and maintain the coupling while the code impulses are being received, means controlled by the received signals to transmit a new set of signals corresponding electrically to the original signals, and means controlled by the cam member to time every individual impulse forming the signals. 7

22. In a telegraph system adapted for the transmission of signals each composed of an' invariable start impulse and a plurality of variable code impulses, a constantly rotating shaft, a rotary member adapted to be coupled to said rotating shaft, a magnet operated by said signals, means controlled by the magnet to start said cam member by coupling said member to said shaft whenever a start impulse is received, cams carried by said member, a contact, and means controlled by the magnet to cause said cams to operate said contact to retransmit signals corresponding to the original signals.

23. Repeater mechanism for regenerating start-stop codes, which comprises, a transmit ting cam started directly by a received starting impulse of a code, means associated with said cam for timing every impulse retransmitted including start and stop impulses, and means including a receiving magnet for determining the electrical nature of every retransmitted impulse.

24. In a telegraph repeater, a cam having an apex for each impulse of a start-stop code, means for starting said cam in response to a received starting impulse, and means controlled by received impulses and cooperating with each apex of said cam to transmit impulses corresponding to received impulses.

25. In a telegraph repeater, a cam having an apex for each impulse of a start-stop code,

means for phasing said cam in response to a received timing impulse, and means controlled by received impulses and cooperating with each apex of said cam to transmit impulses corresponding to received impulses.

26. In a telegraphic repeating deviceyan electromagnet responsive to groups of signals, each group consisting of synchronizing and selecting signals, means for controlling the beginning of the synchronizing and selecting signals of each group, mechanism controlled by the electromagnet in response to a synchronizing signal for rendering said means efiective, a retransmitting contact, and means controlled by the electromagnet after said means has been rendered effective for determining the operation of the retransmitting contact to retransmit synchronizing and selecting signals. a

27. In a regenerative telegraph repeater, a signal controlled member, a series of cam projections corresponding to impulses of spacing character, a second series of cam projections corresponding to impulses of marking character, a retransmitter, and means including a member engageable by all of said cam projections and engaging said retransmitter to control the retransmitter from onecam or the other according to the operation of the signal controlled member.

28. In a regenerative start-stop telegraph repeater, a signal controlled member, a series of parallel connected retransmitting contacts, one corresponding to the start and stop impulses, one corresponding to each of the code impulses, means to close and open the start-stop contact under control of the signal controlled member, means to close the code contacts under control of the signal controlled member, and means to open the code contacts independently of the signal controlled member.

29. In a start-stop regenerative repeater, a signal controlled member, a signal transmitting contact, a multiple lobed cam, means to initiate the operation of the multiple lobed cam under control of the signal controlled member, and means to operate the retransmitting contact under the joint control of the cam and the signal controlled member and effective to operate the retransmitting contact to retransmit a start,

impulse independent of the position of the signal controlled member and-to operate the retransmitting contact to transmit code impulses whose timingseverally is controlled by angular position of said multiple lobed cam and whose electrical characteristics severally are controlled by the position of the signal controlled member.

30. In a telegraphic repeating device, a contact member for retransmitting received signals, an element controlled by the received signals, a timing cam for determining an instant of beginning of retransmitted code signal impulses normally tending to rotate, means under control of said element for releasing said cam for rotation which cooperates during its rotation with said element for operating said contact member to control electrical characteristics in the retransmission of signals as'determined' by said element.

LOUIS M. PO'I'IS.

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