US2446943A - Automatic radio call apparatus - Google Patents

Description

Aug. w, 1948. w. w. M GOFFIN AUTOMATIC RADIO CALL APPARATUS 2 Sheets-Sheet 1 Filed Oct. 28, 1944 nukuuwu o.

ATTORNEY.

Aug. 10, 1948. w. w. M GOFFIN 2,445,943

AUTOMATIC RADIO CALL APPARATUS Filed Oct. 28, 1944 2 Sheets-Sheet 2 Wu T11050 '7? Patented Aug. 10, 1948 QFFICE AUTOMATIC RADIO CALL APPARATUS William Walter McGoflin, Olympia, Wash, as-

signor of one-fifth to S. S.,Baker, New York,

Application October 28, 1944, Serial No. 560,862

8 Claims. 1

This invention relates to a selector of a special type to interpret long and short pulsations, such as the dots and dashes comprising the international Morse code.

An object of this invention is to provide a special selector which is comprised of standard parts embodying a stepper or steppers so interconnected with relays of slow closing and slow opening type with special contact arrangement and connections to thereby form a new unit capable of interpreting dot and dash pulsations.

Another object of this invention is to provide a device which may be preset to any call or letter combination at the will of the operator to give an alarm or operate a local circuit only when the preset combination of pulsations is transmitted to the selector.

A further object of this invention is to provide a selector of a special type that has a very wide tolerance in code speed variation, in which the timing of the dot and dash lengths is not accumulated when a preset arrangement is used.

A further object of this invention is to provide a selector with a preset arrangement that immediately returns to starting position upon receipt of the first pulsation which is not in accordance with the preset combination, and remains at the starting position until another character group of pulsations has started. When the selector has once been stepped up to its final position to operate the local or alarm circuit the selector remains in the final position until manually reset. This selector when not arranged in a preset circuit continues to advance and differentiates in electrical pulsations on the stepper contacts depending on whether or not the selector was pulsed by dot or dash operating circuits to interpret the code, and automatically returning to the starting position immediately on the space or pause which signifies the end of a character or letter.

To the foregoin objects, and others which may hereinafter more fully appear, the invention consists of the novel construction, combination and arrangement of parts, as will be more specifically referred to and illustrated in the accompanying drawings, but it is to be understood that changes, variations, and modifications may be resorted to which fall within the scope of the invention as claimed.

In the drawings:

Fig. 1 is a schematic diagram of an automatic call selector constructed according to one embodiment of this invention.

Figure 2 is a diagrammatic view of the selector arrangement to interpret the code.

Referring to the drawings and first to Figure 1, the numeral 50 designates a conventional radio receiver which has connected to the output side thereof a relay RI by means of wires II and i2. The relay Ri has associated therewith a springpressed armature 13 which is normally held out of engagement with a pair of contacts l4 and I5. Armature I3 is connected by means of a wire I6 to a wire ii and the latter is connected at one end to an armature l8 associated with a signal relay R8. Armature I8 is spring-pressed and'normally engages a double contact l9 connected by means of a wire 21! to wire 2!, which is connected to the negative side of the source of electric current supply. A stepper relay R3 which is adapted to operate a swinging contact arm is connected at one side thereof to a wire 22, and the latter is connected to the positive side of the electric current supply.

A slow acting dash relay R2 is connected at one side thereof to wire 22 by means of a wire 23. The other sides of relays R2 and R3 are connected together by means of a wire 24. Wire 24 has con nected. thereto one end of a wire 25, which at the opposite end is connected to a contact 26. A spring-pressed armature 21 normally engages contact 2% and is associated with release relay RT. Armature 2'! has connected thereto a wire 28, which is connected to a wire 29. Wire 29 at one end thereof is connected to contact i5, and at the other end thereof is electrically connected with a swinging contact wiping arm 35. Arm 30 is mounted on a shaft 3| and shaft 3! is normally biased to rotate in a counterclockwise direction by means of a spring 32.

Shaft 3! has fixed thereon a ratchet 33 and a spring'pressed pawl 34, which is carried by an armature 35 adapted to be drawn towards stepper relay R3 when the latter is energized, is adapted to rotate shaft 3! and swinging arm 30 step by step as relay R3 is energized. Ratchet 33 is held against counterclockwise rotation under the tension of spring 32 by means of a springpressed rocking dog 36. Arm 30 is adapted to Wipe a plurality of contacts 31, which have conwires 39 are connected to a wire 4|. Wires 38 are associated with the dot circuit, whereas wires 39 are associated with the dash circuit. Wire 40 3 is connected to a spring-pressed armature 42 which is insulated from a second armature 43 by insulation 44. The two armatures 42 and 43 are spring-pressed away from relay R2 and are drawn toward relay R2 when the latter is energized.

A contact 45 is disposed in a position for engagement with armature 42 when the latter is drawn towards relay R2. Contact 45 has connected therewith one end of wire 45and the latter is connected to one end of release relay R1. The opposite end of release relay R1 has con.- nected therewith one end of wire 41 and the other end of wire 41 is connected to wire 22;

A contact 48 is disposed in a position to engage armature 43 when relay R2 is de-energized and contact 48 is connected to Wire 41'by means'of a wire 49. Armature 43 is connected to one side of relay R4 which is a quick acting relay by means of a wire 50. The opposite end of relay R4 is connected by means of a wire to wire 41". A resistance element 52 is interposed in wire 45 for reducing the current voltage to relay R4. Wire II- is-connected to a contact 53, which is normally disengaged from a spring-pressed armature 54.

A second armature 55 is fixed to armature 54, there being insulation 56 between the two armatures 54 and 55. Armatures 54' and 55 are connected together by means of a wire or electric conductor 51, and a wire 58 is connected at one end to wire 51 and at the opposite end to contact 59. Contact 59 is normally disposed in spaced relation to an armature 60 associated with relay R5 and armature 60 has connected thereto one end of a wire 6| which is connected to a wir 62. Wire 621is also connected to wire I 1.

Relay R5 is connected by means of a wire 53 to wire 22 and the opposite side of relay R5 is connected by means of a wire 64 to contact I4. Wire 62 is connected to an armature 65, which is insulated from armature 60 by insulation 66, and is normally disengaged from a contact 61 which has connected thereto one end of a wire 68. The other end of wire 68 is connected to an armature 69' correlated with release relay R1 and normally disposed out of engagement with a contact 10. Contact is connected by means of a wire 1I to-a release circuit wire 12.

Aspring-pressed rockable switch arm 13 is connected by means of a wire 14 to wire 68, and has mounted on the free end thereof a contact 11. Contact 11 is adapted to engage a stationar contact 18 when switch arm 30 moves upwardly. Contact 18'has connected thereto one end of wire I1.

An insulating member I9 is carried by switch arm 13 and is disposed in a position whereby arm 30 will engage therewith when the latter is in its released or starting position, so as to thereby break the circuit between contacts 11 and 18,

Armature 55 is normall disposed out of engagement with a contact 80, which has one end of a wire 8| connected therewith. Wire 0| is connected at the opposite end to a contact 82 and the latter is disposed in a position for engagement with an armature 83 insulated by insulation 84 from armature 35. Armature 83 has connected thereto one end of wire 12.

A second contact 85 is disposed in normally spaced relation to armature 83 and has connected thereto one end of a wire 86. The opposite end of wire 86 is connected to an armature 81 which is spring-pressed away from rela R5. A contact 88 is disposed in a position to normally engage armature 81' and contact 88has connected 4 thereto one end of a wire 89. The other end of wire 89 is connected to a wire 90. Wire 90 at one end is connected to an armature 9I associated with relay B5.

A contact 92 is disposed in a position to normally engage armature 9| and has connected thereto one end of a Wire 93, The opposite end of wire 93 is connected to a second armature 94 correlated with relay R6, and insulated from armature 81 by insulation 95. A contact 96 is disposed in a position normally disengaged from armature 94, and is connected to wire 89 by means of a wire 91. Relay R6 is connected to Wire 93 by a wire 98 and the opposite end of relay R6 is connected to positive wire 22 by means of a wire 99.

A wire I00 is connected at one end to wire 46 and the opposite end to a contact IOI. Contact IIlI is disposed. in a. position normally engaging an armature I02, which is insulated from armatures SO'and 9! by insulation I03 and I04, Armature E02 has connected thereto one end of a wire I05, and the opposite end of wire I05 is connected to a plurality of adjustable connectin wires- I00, which are adapted to adjustable or detachable engagement with a plurality of spaced contacts I01.

Wire 90 is connected'at the opposite end thereto to a wire I08, which may be adjustably connected to a selected one of contacts I01. Wire 90'is interposed in the space circuit, whereas wire I05 and wire I06 are interposed in the no space or interval circuit. A rockable switch arm I 09 is mechanically connected with and electrically insulated from shaft 3|, being rockable therewith, and arm I09 has connected'thereto one end of a wire H0. Wire H0 at the opposite end thereof is connected to wire 2|, which is negative side of the current source.

The last one I01 of contacts I01 has connected thereto a wire III. Wire III is also connected to a contact II2 normally engaged by an armature II3 associated with relay R5, and insulated from armature 9! by insulation II4. Armature I I3 has connected thereto one end of wire I I 5 and the opposite end of wire H5 is connected to one side of signal relay R8. The opposite side of signal relay R8 is connected by means of a wire IIB to positive wire 22. An armature or switch arm H1 is moveable with armature I 8 being insulated therefrom by insulation H8 and armature H1 is connected by means of a wire II9 to an audible signal member I20. The opposite side of signal I20 is connected by means of a Wire I2I to positive wire 22.

In order to provide for the automatic return of switch arm 30 at the end of a letter or when an improper signal is received in receiver I0, I have provided a combined armature and lever I22, which is insulated by insulation I23 from armature 39 and is disposed in confronting position with respect to release relay R1. Armature I22 is formed with a lever arm I24 and a pair of push rods I25 and I26 are connected to lever arm E24 and engage dog 36 and pawl 34 respectively, Release relay R1 ma have the circuit thereto manually closed by means of a manual switch I21 interposed in wire 12 and normally biased to an open position.

Referring now to Figure 2, there is disclosed a modification of this invention wherein the signal impulses are adapted to be interpreted and imprinted by means of a teletype apparatus, or the like. The signal impulses are transmitted over wires I28 and I29, wire I28 being connected to wire I30, which is connected 'between a stepper relay I3 I and a second relay I32.

The opposite sides of relays I31 and I32 are also connected together by means of a wire I33. Wire I29 is connected to negative wire I34 which is connected to a source of current supply, and wire I33 is connected by means of Wires I35 and I36 to a positive wire I31. Relay I32 has asso ciated therewith an armature I38 connected by a wire I39 to wire I29, which is connected to wire I34. A contact I4! is disposed in normally spaced relation to armature I88, the latter being springpressed to circuit breaking position and contact I4! is connected by means of a wire I42 to a swinging switch arm I43. Arm I43 is secured to a shaft I44, which has fiXBCI thereto a ratchet I45, and ratchet I45 is normally urged to rotate in a counterclockwise direction by means of a spring I48.

A dog I41, which is carried by an armature I48 associated with relay I3I, engages ratchet I45 to move switch arm I 43 step by step in a clockwise direction. A plurality of cont-acts I 49 are disposed in a position for Wiping engagement by switch arm I43 and contacts I49 are connected by means of wires I59 to one side of a plurality of solenoids I5I. Solenoids I5I are provided with movable cores I52, which are extended from the solenoids and provide a locking means for a plurality of series of type bars I53, I54, I55, I56 and I51.

The opposite sides of solenoids I52 are conneoted by means of wires I58 and I59 to wire I38, which is connected to positive wire I31. The type bars I53 to I51 are actuated by means of solenoids I59, IGI, I92, I63 and IE4, respectively. The solenoids I59 to I54 are connected to Wire I59 by means of a wire I55. The opposite ends of solenoids I59 to I54 are connected to spaced contacts I55, I51, I68, I59 and H4 by means of wires I1I, I12, I13, I14 and I15, respectively.

A switch arm I18, which is mechanically connected to and insulated from switch arm I43 and shaft I44, is adapted to wipe over contacts I 55 to I18, respectively, upon rocking .or rotation of shaft I44. Switch arm I15 has a wire I11 connected thereto and wire I11 is connected to a contact I18 normally engaging an armature I19 disposed in confronting position to a relay I80.

Armature I19, which is spring-pressed to engage contact I18 is connected by means of a wire I'SI to negative wire I34. Relay I89 is connected by means of wire I49 to wire I28, and is connected by means of a wire I32 to wire I35.

In order to provide for the release of switch arm I43 so that spring I48 may return this arm and also arm I15 to a starting position, I have provided a relay I83 which is connected at one side to wire I31. The other side of relay I83 is connected by a wire I84 to wire I11. A springpressed armature I85 is correlated with relay I83 and is mechanically connected by means of a flexible connector or other suitable mean I85 to armature I48, so that when armature I85 is drawn in the direction of relay I83 when the latter is energized, armature I48 will be pulled away from relay I3I and pawl I41 will be pulled to a di engaged position with respect to ratchet I45.

In operation this device will function as follows: The impulses are received by receiver I and these impulses activate relay RI. On each impulse, that is either a dot or dash impulse, negative potential is set up through armature I3 and contact I4 to relay R5. Relay R is a quick closing but slow releasing relay and will stay closed so long as impulses are received in receiver III in the absence of a letter space. At the same time that relay R5 is energized, stepper relay R3 is energized and after release thereof at the end of an impulse moves stepper swit'ch arm 39 for- Ward one step through spring action. Relay R3 receives negative potential from contact I5, wire 29, wire 28, armature 21, wire 25 and wire 24.

When relay R3 is energized, relay R2, which is a slow closing relay, is also energized, and if the impulse is a dot impulse, the duration of the impulse is not sufficient to activate relay R2 so that negative potential from wire 49 remains broken at contact 45.

Dot operation Dash operation After stepper switch arm '39 moves forward three steps, it will engage the fourth contact 31 with which the first dash. wire 39 is connected. Assuming that, as shown, the next three impulses are dash impulses, relays RI, R5, R4, R2, and R3 will be energized and will operate. Stepper relay R3 will move stepper arm 3% forward three steps in sequence at the termination of each clash impulse.

At the beginning of each impulse on a dash connection, negative potential is continued from stopper arm 50, through wire 39, wire II, resistor 52, relay R4, armature 43 and contact 48 to positive wire 22. Armature 43 and contact 48 are engaged at this time because the timing relay R2 has not yet closed. Relay R4 closes at the beginning of the dash impulse and continues the negative potential from armature 55 to contact 88, through wire 8I to contact 82 of relay R3. R3 being closed with the impulse, armature 83 is disengaged from contact 82, thu withholding the negative potential from the release relay R1. If the impulse were to be of short duration so that armature 83 engages contact 82 while 55 and 89 are engaged, the release relay R1 is opera'ted.

When relay R2 .is operated by a dash impulse, the circuit to release relay R1 is opened by the de-energization of relay R4 which thereupon disengages armature 55 and con-tact 80. Such deenergization of relay R4 is effected by the disengagement of armature 43 and contact 48 when a dash impulse operates relay R2.

Rejection-Dash impulses Assume that, as shown, the device is set to initially receive three dot impulses, but actually one of these impulses is a dash impulse. When the improper dash impulse is thus received, release relay R1 is energized as follows: Relay R2 will be permitted to close and armature 42 will engage contact 45 so that negative potential to release relay R1 will flow from arm 30, wire 38, wire 45, armature 42, Contact 45 and wire 46.

When release relay R1 is energized, stepper dog 34 and holding dog 36 are disengaged from ratchet 33 so that spring 32 will return arm 38 to starting position. At the same time, negative en a es:

potential to relays R3: and R! will be broken bysmovement of armature 2-1 away from contact 28. The operation of relay R'I closes armature 69 with contact II! which electrically locks relay R1 providing a negative return through armature 6'9, wire'88, armature I3, contacts 11, I8, wire II. This lock is retained until stepper arm 30 is returned by spring 32 to starting position. In the event the pulsations are still coming in and relay R5'is closed, the electrical lock is still maintained after stepper arm 30'moves armature 13 to circuit breaking position inasmuch as relay R5 will hold armature 65 against contact 61, and negative potential is maintained through wire 68. to wire 62. When the impulses cease',"reiay-' R5 will open when a letter space occurs and negative potential to release relay R! will be broken so that relays R2, R3, R4 will again be set up for operation. This assures that after a reset of the stepper arm, the device will not recommence operation on part of aletter.

Rejection-dot impulse Assuming that, as shown in Fig. 1, the device is set to receive three dots followed by three dashes, and the first three impulses are dots so that stepper arm 30 will have moved up three steps as previously described, the next impulses must be dash impulses. If one of the impulses is a dot and arm 30 is in circuit with a dash wire 39, relay R2 will not close, but relay R4 will close and negative potential at the end of such dot will be supplied release relay R'I from wire 62, wire BI, armature 80, contact 58, wire 58, armature 55', contact 80, wire 8I, contact 82, armature 03, wire I2 and wire 48, the latter being connected to wire 12. It should be noted that at the end of the dot, relay R3 is released so as to engage contact 82 and armature 83. Relay R! will then operate as hereinafter described to release arm 30 for operation by spring 3| to starting position.

Space check (relay R6) The function of relay R6 is to check the spaces or lack of spaces between characters or combinations of characters and impulses in cooperation with relay R5. Arm I09 is mechanically connected with arm 30, but is insulated therefrom and moves step by step with arm 30. Wires I06, which are in the no space circuit are connected to selected contacts I01, and at least one wire 838 is connected to a selected contact I01, as shown in Fig. 1.

Negative potential to release relay R1 is supplied from wire 2I, wire IIO, arm I09, contact I01, wire I08, wire I05, armature I02, contact IOI, wire I00, and wire 46. With no space between the impulses, relay R5 will remain closed so that negative potential is broken between armature I02 and contact IOI, and relay RI does not close.

If a space is made while arm I09 is on no space contact I'I, negative potential is supplied release relay R! as follows: Relay R will open and'a-rmature I02 will engage contact IOI.

Space acceptance Wire I08 is in the space acceptance circuit and. when arm I09 engagescontact I 01 with which wire I08 is connected, if a space is made between impulses relay R5 opens and armature 8I engages contact 92. Negative potential is supplied to relay R6 as follows: Wire IIEI; arm I09, wire I08, wire 90, armature 9|, contact 92, wire 93, wire 98. Relay R6 will close and armature 84 will engage contact 88'. Negative circuitwillbe broken at 81, 88, and as relay R3 is open, armature 83 will be disengaged from contact 85 so that negative potential to release relay RI will be broken. Thus, at the beginning of the next pulsation, when R3 closes, armature 83 engages contact 85 but relay R1 is not operated because R6 is still closed and the negative circuit is broken between armature 81 and contact 88;

Assuming, however, that there is no space between the impulses when arm I09 is associated with wire I08, the release relay R1 is closed as follows: Negative potential passes from arm I08, wire I08, wire 90, wire 89, contact 88, armature 8?, wire 88, contact 85, armature 83, wire "I2 and wire 46. This occurs at the beginning of the next impulse which comes in without a sufficient space to allow R5 to release.

What is claimed is:

1. In a signalling system for identifying a transmission of Morse code letters constituting a desired call, the combination of an alarm, electrical circuit means to operate said alarm, a dual selector device connected on the one hand to dot or dash, and on the other hand to interval or space circuits, and operating to effectively advance from a starting position to a position where it closes said electrical circuit means when a complete desired transmission has been received first relay means for actuating said selector device in the desired advance, se-cond relay means for returning the device to said starting position when an improper signal is received during said transmission, a first time delay relay closing onincoming signals of dash length whereby the operation of said first time delay relay characterizes the reception of a dash as distinguished from a dot, non-operation thereof determining the dot character of the pulsation and being operative to withhold operating power from said second relay means so as to permit the advance of said selector device when said selector device has been set to a dot position, and operation thereof permitting the advance of the selector device when it has been set to a dash position by similarly withholding operating power to said second relay means, a second time delay relay operated by incoming signals and releasing at signal interruptions of space length whereby the release of said second time delay relay characterizes the reception of a space as distinguished from an interval, non-release thereof determining the interval character of the interruption so as to permit the advance of said selector device when it is set to interval position by withholding operating power from said second relay means and operation thereof permitting the selector device to advance when set to space position by similarly withholding operating power from said second relay means whereby both of said time delay relays are operable on said second relay means so as to cause said selector device to be returned to starting position when an improper character or interruption is received.

2. In a signalling system for identifying a transmission of Morse code letters constituting a desired call, the combination of an alarm, electrical circuit means to operate said alarm, a selector device operating to'progress in steps from a starting position to a position where it closes said electrical circuit means when a complete predetermined transmission has been received, a release relay'for returning said selector device to said starting position when an undesired call is received, said selector device comprising a first series of switch elements for pre-selecting the desired dot and dash characters, a second series of switch elements for pre-selecting the space and interval interruptions and a pair of mechanically ganged switch arms for progressing along the respective series of switch elements as the proper pulsations from said transmission are applied to said system, a slow closing relay energized by said pulsations and operative to close when a pulsation of dash length is received, said release relay being operated by said slow closing relay through said. first series of switch elements according to the pre-se1ection of said dot and dash characters thereon, a slow releasing relay energized at each received pulsation and operative to open at a signal interruption of space length, said release relay being operated by said slow releasing relay through said second series of switch elements according to the pre-selection of said space and interval interruptions thereon, a spring normally urging said selector device to its starting position when an improper signal component is received during said, transmission, a pawl for maintaining sai-d selector device in a progressed position against the action of said spring, said release relay when operated by either said slow closing or slow releasing relay being operable upon said pawl so as to permit the return to starting position of said selector device.

3, In a signalling system for identifying a transmission of Morse code letter pulsations constituting a desired call, the combination of an alarm, electrical circuit means to operate said alarm, a selector device operating to progress in steps from a starting position to a position where it closes said electrical circuit means when a complete predetermined transmission has been received, release relay means for returning said selector device to said starting position when an I undesired call is received, said selector device comprising a first series of switch elements for pre-selecting the desired dot and dash characters, a second series of switch elements for pre-selecting the pace and interval interruptions and switch arm means for progressing along the respective series of switch elements as the proper pulsations from said transmission are applied to said system, a slow closing relay energized by said pulsations and operative to close when a pulsation of dash length is received, said release relay means being operated by said slow closing relay through said first series of switch elements according to the pre-selection of said dot and dash characters thereon, a slow releasing relay energized at each a received pulsation and operative to open a signal interruption of space length, said release relay means being operated by said slow releasing relay through said second series of switch elements according to the preselection of said space and interval interruptions thereon, non-operation of said slow closing and slow releasing relays respectively determining the dot and interval natures of a received pulsation.

4. In a signalling system for identifying Morse code signal transmissions, the combination of an alarm, electrical circuit means to operate said alarm, a selector device including a spaced series of contacts and operating to effectively progress along said contacts from a starting position to a position where it closes said electrical circuit means when a complete desired transmission has been received, an input circuit for feeding said transmission in the form of impulses to the apparatus, a slow closing timing relay connected to said input circuit so as to commence operation thereof each time an impulse is fed by said input circuit and whereby closing of said relay characterizes the reception of a dash as distinguished from a dot, a slow releasing timing relay operated by and closing with each said impulse, and opening at signal interruptions of space length whereby the opening of said slow releasing timing relay characterizes the reception of a space as distinguished from an interval, said spaced series of contacts serving as dot, dash, interval and space pre-connection means whereby said selector device may be electrically pre-connected according to the desired progression of signal components, each of said timing relays including electrical contacts for establishing predetermined electrica1 circuits according to the respectiv operation or non-operation of each of said timing relays as determined by said fed impulses, said predetermined electrical circuits being formed between said timing relays and said pre-connection means of said selector device during its progressive action, selector device actuating means for driving said selector device in the desired progression until said alarm is operated, release relay means operative on said selector device for returning it to said starting position when an incoming signal component does not correspond to the pre-connection of said selector device, sai-d release relay means having an operating winding included in, so as to be operated by, one of said predetermined electrica1 circuits according to the pre-connections of said selector device and the respective operation of said timing relays, said one predetermined electrical circuit being formed by said pre-connection means and the electrical contacts of said timing relays when the action of said timing relays as determined by said fed impulses does not correspond to the pre-connections of said selector device, non-operation of said release relay means permitting said desired progression.

5. A signalling system according to claim 4 and including a third relay controlled by said slow closing relay, said third relay having a Winding connected through said input circuit and said preconnection means so as to be energized at each incoming impulse when a dash character is preselected and being controlled by said slow closing relay so as to be de-energized when a dash is received, said de-energization thereof withholding operating power from said release means, and a fourth relay controlled by said slow releasing relay, said fourth relay having a winding connected through contacts of said slow releasing relay so as to be energized when a space is preselected and occurs in the transmission, the energization of said fourth relay similarly withholding operating power from said release means when said selector device is pre-connected to select spaces.

6. A signalling system according to claim 5 and wherein said selector device comprises two series of switch contacts, one of said series of switch contacts representing the dot and dash circuits of the system whereby the selector device may be pre-connected to select both the dots and dashes in a desired transmission, and the other of said series of switch contacts representing the interval and space circuits of the system whereby the selector device may be pre-connected to select both the intervals and spaces of the desired transmission, and a pair of mechanically linked switch arms for respectively progressing over both series of switch contacts.

7. Asignalling-system according .to claim6 and wherein said selector device actuating means comprises another relay, both of said timing relays, and said selector device actuating relay .being simultaneously fed bylincoming impulses from said input circuit.

8. 1m a signalling system for identifying a transmission of Morsecode letter pulsations constituting a desired call, the combination of 'an alarm, electrical circuit means to operate said alarm, aselector device operating to progress in stepsfrom astarting position to a position where it closes said electrical circuit means when a .complete predetermined transmission has been received, release relay means for returning said :selector device to said starting position whenan undesired call is -received,,said selector device comprising a first seriesof switch elements preconnected was to pre-selectthe desired dot and "dash characters, 'a'rsecond series of switch elemnents preconnect-ed so as to pre-select the space "and interval interruptions and switch arm means for progressing along the respective series of switch-elements as the proper pulsations from ---said transmission are applied to said system, a first ,timing relay op erating to :distinguish between received-:dot and :dash impulsespand being opercatively'connected to said "release relay means iaccordingivtoathe"preaselectionlof said dot and dash 'chara'cters, andrasecondtiming relay operating: to adistinguishbetween received space and interval interruptions, and .being operatively connected-to saidrelease relay-means according to the preesel'ection of said space and interval interruptions, said first timing relay being a slow closing relay which is energized by received pulsations and -has' a delay-time-so that operation or ions-operation of said slowclosing relay respectively determines ,thcdotor dash nature of a receivedpulsation, said ,second timing relay being a slowreleasingrelay energized at each received pulsation and having-a delay time so that-operation or non-operation of said slow releasing relay respectively determines the space or interval na- .ture of an interruption in the signal transmission, afirst associated relay cooperating-with said first timing relayand operative to withhold operating power to said release relay means when an incoming dot or-dash pulsation corresponds to the pro-connections of said first series of switch elements, and a second associated relay cooperating with said second timing relay so as to similarly withhold operating power to said release relay means when an incoming space or interval interruption corresponds to the ,pre-connections of said second series of switch elements.

WILLIAM WALTER MoGOFFIN.

REFERENCES CITED The following references are of record in the :file of this patent:

UNITED STATES PATENTS Number Name Date Re. 19,321 Reiber Sept. 18, 1934 1,287,396 Morse Dec. 10, 1918 1,628,653 Chauveau May 1-7, 1927 1,655,689 Chauveau Jan. 10, 1928 1,661,748 Chauvea-u Mar. 6, 1928 1,695,840 Chauveau Dec. 18, 1928 1,763,390 Davis June 10,1930 2,130,166 Wattanabe Sept. 13, 1938 2,201,561 Norrito May 21, 1940 2,334,575 'Neiswinter, ,Nov. 16,1943

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