US1936900A - Means of communication - Google Patents

Description

Nov.28,1933. v M BUGGE L93Q900 MEANS OF COMMUNICATION Filed Jan. 12. 1933 7 Sheets-Sheet l INVEN OR ATTORN EYS Nov. 28, 1933. v, M, B E 1,936,900

MEANS OF COMMUNICATION 4 Filed Jan. 12, 1933 '7 Sheets-Sheet 2 ATTORNEY NOV. 28, 1933. v BUGGE 1,936,900

MEANS OF COMMUNICATION Filed Jan. 12, 1933 7 Sheets-Sheet 3 SPAKCE Fig. 4

IN V EN TOR. W

A TTORNEYS.

Nov. 28, 1933. v. M. BUGGE 1,936,900

MEANS OF COMMUNIbATION a Filed Jan. 12,' 1933 7 Sheets-Sheet 4 II IIIIIIHIHI I INVENTOR ATTORNEYS NOV. 28, 1933. I V BUGGE 1,936,900

MEANS OF COMMUNICATION Filed Jan. 12, 1955 7 sheets-sheet 5 FL' .9 30 28 /29d /29C NVEN TOR. w

A TTORNEYS.

Nov. 28, 1933.

v. M. BUGGE MEANS OF COMMUNICATION Filed Jan. 12, 1933 7 Sheets-Sheet 6 m mww ATTORNEY5.

NOV. 28, 1933. v BUGGE 1,936,900

MEANS OF C OMMUN I CATION Filed Jan. 12, 1933 7 Sheets-Sheet 7 f WfNVE OR it ATTORNEY5 Fig; 1a

Patented Nov. 28,-1933 UNITED STATES MEANS OF COMMUNICATION Vernon M. Bugge, Southport, Conn., assignor to The Teletalk Corporation, Bridgeport, Comm, a corporation of Connecticut Application January 12, 1933. Serial No. 651,246

12 Claims. (Cl. 179-4) This invention relates to a method and means of communication making possible the transmission of messages between stations remotely situated over a two wire circuit, and whereby letters,

6 numerals, or other symbols may be correctly recorded at both the sending and receiving stations by means controlled by an operator at the sending station.

It is an object of the invention to provide an improved and simplified construction whereby an operator at a sending station, bymerely operating a keyboard similar to that of a typewriter, may record a message at the receiving station over a two wire circuit and may also, if desired,

record the same message at the sending .station.

It is also an object of the invention to provide such a system which may be used with a standard telephone circuit through a standard central exchange as the connecting circuit between the sending and receiving stations, and may be socontrolled' that if the called party does not answer at the receiving station the calling party at the sending station may leave a written message at the receiving station.

E Other objects and advantages of the invention will become apparent as the description proceeds.

The principle on which the system operates is based on the transmission of signals of predetermined current values over an electric circuit connected with apparatus which will give a definite and different response to each signal .value. The system comprises in general a keyboard at the sending station somewhat similar to that of a conventional typewriter provided with keys to establish electrical circuits for all letters, numerals and symbols it is desired to reproduce. The circuits are constructed and arranged to provide the proper circuit condition to supply the desired signals or current values to the main circuit connecting the stations, and also to establish a control circuit. Each key therefore sets up or completes two independent circuits. Connected with the main circuit at each station is a magnetically operated selector \unit consisting of a number of solenoid magnets operating to close various circuits in response to the signals 01 definite current values and thus operate a recording device, such for example as a printing machine having type bars, tape, inked ribbon, feed mechanismand shift mechanism. The mechanism also includes a magnetically operated interlock so arranged that when the selector has closed the circuit corresponding to the signal value and the.-

printer has operated to record the signal, it closes the circuit to a relaywhich opens the circuit to the selector magnets and printer thereby restoring the system to the normal condition for transmission of the next signal.

In the accompanying drawings I have shown 0 the mechanism and diagrams of the circuits for performing these operations. It will be understood that this mechanism is shown merely by way of example as numerous modifications and changes in the details of construction may be em- 35 ployed without departing from the principles of the invention.

In these drawings: Fig. 1 is a partial side elevation and partial section of an apparatus-which may be used at 7 both the sending and-receiving stations;

Fig. 2 is a front elevation;

Fig. 3 is a top plan view;

Fig. 4 is a side elevation of the selector mechanism looking toward the bottom of Fig. 3;

Fig. 5 is a top plan view of the base portion and showing the feed for the inked ribbon;

Fig. 6 is a vertical section substantially on line 66 of Fig. 5 but showing a type bar in position;

Fig. 7 is a detailed section through the selector mechanism; I

Fig. 8 is a front elevation thereof;

Fig. 9 is a partial section and a partial elevation on an enlarged scale of a portion of the selector mechanism;

Figs. 10 and 11 are detailed views of a ribbon feed mechanism;

Fig. 12 is a front elevation and partial section through the tape feed mechanism;

Fig. 13 is a detail of a shift mechanism in one position;

Fig. 14 shows it in another position;

Fig. 15 is a wiring diagram of a system connecting two stations;

Fig. 16 is a diagram showing a modification;-

Fig. 17 is a diagram of the selector; and

Fig. 18 is a wiring diagram showing how the device may be operated with a telephone circuit.

The same mechanism. as shown. is employed at both the sending and receiving stations and it is preferred that the devices be connected so that they both operatetogether to record the message at both stations. The mechanism illustrated comprises any suitable base 20 of any suitable material, such as wood. on which the various elements of the device are mounted making a unitary structure which can be installed as such at each station. This unitary structure can be constructed and assembled and tested at the manu-' facturing plant, and then installed at the station by merely making the necessary electrical conections.

Mounted on this base is a keyboard indicated at 21 and comprising any suitable number of keys 22, similar to typewriter keys, for operation in sending and recording the message. These keys may be constructed and mounted in various ways, but as shown they each comprise a rod 23 carrying the cap for the key and mounted for vertical movement in insulating supports 24 and 2411. On the underside of 24 is mounted a pair of spring contacts 25 for each key, each key operating a contact 26, which when depressed will bridge the contacts 25 to close a circuit. The keys are normally held in the uppermost position and return to this position after being operated by a spring 27. On the underside of 2411 are mounted spring contacts '76 adapted to be bridged by a contact 80 on the rod when the key is depressed.

Also mounted on the base is a recording mechaanism, in the present instance comprising a series of type bars and operating mechanism therefor. A type bar is shown at 28 pivoted at 29 and each bar is operated by a solenoid 30 controlled by the proper key and the selector mechanism, as will later be described. Associated with each solenoid is an armature 31 to be operated thereby, this armature being connected by a pivoted link 32 to a lever 33 pivoted at 34 ona suitable support 35, the other end of this lever being connected by a link 36 to the type bar 28. The type bar is normally held in a retracted position indicated in Figs. 1 and 6 by a spring 3'7, the backward movement of the bars being limited by a suitable stop 38. The core 39 of the solenoid 30 is extended'throughout the height of the solenoid but has a passage 40 leading from its upper end for the armature 31. This construction provides a stronger magnetic field with a given number of ampere turns in the solenoid eflective on the armature and gives greater operating force and requires less movement of the armature for operation of the type bar. The stop 38 is curved and the type bars all face toward a common center indicated approximately at 41 so that as the bars are operated the message will be printed in a straight line. However, as the bars swing backwardly from the printing position, indicated in broken lines, Fig. 6, to rest against the stop 38 they pass through and to the rear of the vertical line 42 through their pivots 29. Movement to the rear of this line causes them to separate somewhat and therefore a larger number of type bars can be mounted in a given space. Also, the solenoids 30 for operating the different type bars are arranged in a plurality of curved rows in staggered relation, as indicated in Fig. 5, which permits the. mounting of a much greater number of solenoids in the same space. There are only a few of the solenoids shown in the drawings but it is to be understood that there is an operating solenoid for each type bar. There are also solenoids for shifting the tape so as to type in upper 'or lower case as indicated at 43 in Figs. 6, 13 and as indicated in Fig. 13 and in dotted lines Fig. 6

to shift the tape 48 and the platen 50 to the left as indicated. This solenoid 43 is energized from a suitable control circuit as will later be described.

The type bars when operated also operate any suitable feed mechanism for the inked ribbon 51. For example they may engage a curved bar 52 mounted on vertically slidable supports 53 (Figs. 10 and 11) operating a suitable pawl and ratchet 54 to rotate a pulley 55 and through a suitable driving connection as a small belt 56 to operate pulley 57 to rotate the spools 58 on which the ribbon is coiled, the bar 52 being normally held in the upper position by springs 59.

The tape 48 on which the message is printed may be fed by any suitable means, but in this instance I have shown it as coiled on a spool within the casing 60 and running over suitable guides 61 and 62 to the upper side of the platen and feed roll 59. On the opposite side it may run under a guide roller 64 held against the top of the tape to press it against the feed roll 50 by a spring 65, and it may issue through a guide 66. The feed roll and platen 50 is operated by a step by step movement, such as a solenoid 6'7 energized each timea type bar or the spacer mechanism is operated to advance the feed roll 50 and the tape the space between successive symbols. The armature 68 of this solenoid operates a ratchet feed 69 engaging a toothed wheel '70 connected to the feed roll. A hold-back '71 engaging the teeth of the wheel '70 prevents the rolls turning backward on reverse movement of the ratchet 69.

An electrical system connecting two stations is shown in Fig. 15 and this figure also shows the apparatus and local circuit at the two stations. As shown, two stations are connected by a metallic circuit through the main line wires '72 and 73, a battery for supplying current to this main line circuit being shown at '74. The local or control circuit at each station is shown in the light lines, and current for each of these circuits may be supplied by battery '75. Two keys 22 of the typing or recording mechanism are shown at each station for illustration, but it will be understood that the number of keys actually used is much greater. It will be noted that contacts '76 controlled by these keys are connected across the conductors '7'7 and '78 and that there is a cross connection for each key. Thus in this system, if we use thirty-two keys there will be thirty-two of these cross connections. In the cross connection for each key is a series resistance '79 but this resistance for each key is different from that of each of the other keys so that when any key is depressed it closes the switch to bridge contacts '76 and the main line circuit through '72 and '73 is closed and a predetermined definite current value is supplied thereto if the relay switch 81 is closed. This relay 81 will be closed as soon as the switch 26 also controlled by the key 22 is closed as the key is depressed, the current being supplied to this switch and the relay 81 from the battery '75 through the leads 83, 84, relay 85, leads 86, 8'7, and 88. It will be noted on the drawings that the resistance '79 for the upper key 22 is different, in the present instance greater than that for the lower key.

Connected with one contact'25 of theswitch 26 as at 89 is a lead 90 leading to spring contacts or switch 91 which is normally in the open position but is operated by an armature 92 controlled by one of the coils 93, 94, 95 or 96 of the selector unit which will later be described. This selector in the present instance comprises four of these coils connected in parallel, although they may be connected in series if desired, or combination series and parallel, but as will later be explained the number of coils may be varied. These coils are in the main line circuit 72, '73 so that as soon as a symbol key 22 is depressed the predetermined definite current value sent out on the line passes through these coils, it being assumed that the hand switch 97 at the receiving station is closed and that at the sending station is open. The other lead from the switch 91 and indicated at 98 passes to the distributing relay 85.

Associated with each of the selector coils 96 is a neutralizing coil 99 wound in opposition to the associated coils 93, 94, 95 or 96, and are of definite values as will later be described. These coils are connected in parallel, but may be connected in series or combination series and parallel, and are controlled by the normally open relay switch 100 which is connected by the leads 90, 101, 102

and 88 to the battery 75. This switch 100 is controlled by a relay coil 103 in the main line circuit.

The switch 100 also controls the tape shift solenoid 43. The coil 104 of relay is connected by lead 105 to the one side of the battery 75 and on the other side by lead 106 to the contact 107 on the relay and also to one side of the switch 108. The other side of this switch is connected to the lead 84 and this switch is operated by one of the arrester coils l09 which are connected to a contact 110 in the relay 85 and to a switch or spring contact 111 controlled by the sliding bars of the selector mechanism indicated at 112 as will later be described. It will be understood that there is a switch or spring contact 111 for each type bar and that each one of these switches controls a given type bar operating solenoid 30. The other lead 113 from this solenoid is connected to the other side of the battery 75 by the lead 88. This same layout is duplicated in the other station as will be apparent from the drawings.

The function of the selector is to establish the correct circuit to a printer so that the symbol corresponding to a definite signal value is printed. As indicated above it comprises four solenoid magnets 93, 94, 95 and 96 and is shown more in detail in Figs. 1, 3, 4, 7, 8 and 9.

As shown in Figs. 7 and 9, each one of these coils embraces a core 114 in which is slidable an armature plunger 115, this plunger being normally held in the extended or outer position of Figs. 1 to 4 by a spring 116 between the inner end of the plunger and an adjustable sleeve 117 threaded at 118 into a mounting block 119. This sleeve may have a polygonal head 120 whereby it may be adjusted to vary the loading of the spring 116. The plunger 115 may have an extension 115a slidable in the sleeve 117 to form a guiding means for the plunger and maintain it central within the solenoid coil. The mounting block 119 has a threaded extension 121 passing through 'an opening in the mounting support 122 and by which it may be secured through a nut 123.

As mentioned above, one of these coils, in the present instance the coil 93, controls the armature 92 of the spring contact switch 91, and as shown in Figs. '7 and 9 this may be located at the opposite end from the plunger 115, but it will be evident that as soon as the solenoid 93 is energized the armature 92 is drawn inwardly to close switch contacts 91 as indicated in Fig. 9, these contacts being normally separated or in the open position. Connected to the outer end of each armature 115 as by a pin and slot connection 124 is a lever 125 pivotally mounted at 126. Eachlever is connected by any suitable means, such as a pin and slot 127 with a code bar 112. Each of these code bars is mounted to slide in a channel in the insulated support -128 and over a number of. contact making plungers 129 for operating the spring switch contacts 111. The

switch contacts 111 are normally in open position or separated so that as a plunger 129 is forced down by the code bars it closes the corresponding circuit. As indicated in Figs. 4 and 15 all the lower members 1111 of these switches may be connected to one side of battery '75 through leads 109a, 84 and 83 while the upper member of each is connected by a lead 113 to its proper type bar operating solenoid 30 and through lead 88 to the other side of the battery.

As shown in Figs. 3 and 17 each code bar 112 controls four plungers 129 each of which controls a switch 111. The plungers 129 are arranged in four rows of four plungers in a row, there being one row in the path of movement of each code bar so that as the code bar' is moved outwardly and the portion 130 stops overthe plunger, the code bar is depressed causing the corresponding circuit through a type bar solenoid 30 to be closed. The code bars are cut away on their under edges as indicated at 131 to give clearance for the upper ends of the plungers and permit them to move to their upper or open position for the corresponding contacts 111. The springs 116 for each solenoid 93, 94, 95 and 96 is so designed or adjusted that it permits movement of the corresponding bar 112 only a given amount for each definite predetermined current value that is supplied to the line 72. That is, each spring 116 has a different load characteristic so that although the magnet or solenoid coils 93, 94, 95 and 96 are identical as to electrical characteristics, subject to the same current the position taken by each core will be different from the others. As the code bars are connected to the cores their relative positions will also be different. Thus for example, for one key 22 its resistance '79 is such that as the circuit is closed on depression of the key a current value of only suflicient strength is supplied to the line to move the first code bar 112a forward over the first plunger 129a as in Fig. 17 and depress this plunger to close the corresponding circuit at 111. The other code bars do not move with this current value. If the key of the next larger current value is depressed then the code bar 112a is moved forward sufficient to depress the plunger 12% and so on, the first four current values moving the code bar 112a forward four different distances to correspond with the four plungers in line with it. If the fifth key 22 is depressed the current value is sufilcient to move the code bar 112a beyond its four plungers 129, as indicated in Fig. 7, but the next code bar 11% is moved forward sufficient to depress its first plunger 129a and so on throughout the entire series and corresponding to sixteen different characters, it being understood that each plunger 129 controls a circuit for a solenoid 30 of a type bar so that the corresponding type bar 28 at both the receiving and sending stations is operated on depression of the proper key to print the corresponding letter or symbol on the tape 48.

During the operation of these first sixteen keys the current values supplied to the line by these keys are not suflicient to operate the relay 103 and therefore the neutralizing coils 99 wound in opposition to coils 93, 94, 95 and 96 are not energized. The relay 103 is, however, designed to operate on depression of the next or seventeenth key and each of the following keys, and the neutralizing coils 99 when energized are sufficient to cancel out or neutralize the fields produced by the coils 93, 94, 95 and 96 when operating on the current equal to the sixteenth key. Therefore, on operation of the seventeenth key the relay 103 operates to close the switch 100 and energize the neutralizing coils 99. Thus the code bars for the solenoids 94, 95 and 96 do not move but remain in their retracted position while the first code bar 112a moves out to depress the plunger 129a, there being suflicient current passed through the resistance 79 for the seventeenth key to equal the cancelling effect of the neutralizing coil 99 for the solenoid 93 and sufficient additional current to move the code bar 112a to its first position. Operation of the keys above the seventeenth will add corresponding increments of current to again operate the code bars 112 to operate the sixteen solenoids 30 for the type bars.

- It will, however, be noted from Fig'. 15 that when the relay 103 closes the switch 100 to energize the neutralizing coils 99 it also closes the circuit through the shift solenoid 43 which will shift the platen and the. guide for the printing tape from lower to upper case to print a diiferent set of symbols or letters with the same type bars. Therefore with the sixteen solenoids and the sixteen type bars I can print thirty-twoletters or symbols.

The operation of sending a message is as follows:

We will assume that the station at the left of Fig. 15 is the sending station, while that at the right of this figure is the receiving station. The hand operated switch 97 is normally closed at each station, or one or both may be kept open if means is provided for signalling when a message is to be sent. This latter arrangement would save battery current when the system is not in use. A preferred arrangement whereby no signalling means is required and which will use only a small current when the system is idle is shown in Fig. 16. This latter arrangement will be described later. If we assume the switches 97 are closed, the party at the sending station opens his switch 97 when he desires to send a message. The system is now in condition for printing, the switch 97 at the receiving station remaining closed. If he depresses a key 22, corresponding to any given letter or symbol, a circuit is completed by switch 26 through its contacts 25 to the coil of the relay 81, thus closing this switch. A main line circuit is thus established through the switch 80 of this key, (as this switch was also closed when the key was depressed) its resistance '79 and relay switch 81 to the selector coils 93, 94, 95 and 96 of the sending station, through the line wire 72 to the selector coils 93, 94, 95 and 96 of the receiving station and through closed switch 97 back on the return 73. This will supply a current of a predetermined definite value to the selector coils at both stations, and the code bars of the selectors at both the sending and receiving stations will then be positioned according to the strength of this current as above described in connection with these code bars, thus causing the proper code bar operated contact switch 111 to be closed and the circuit established at both stations through the proper type bar operating solenoid 30 to print the desired letter orcharacter. Also, as soon as the solenoid 93 is energized the interlock 91 will close at both stations giving a parallel circuit for the switch 26. This is not needed at the sending station as closing of the switch 26 by the key has supplied current to the wire 84 and through the coils 109- to the code bar operated contacts 111, but at the receiving station the key operated switches 26 are all open and therefore closing of the interlock 91 at this station completes the circuit from the local battery '75 at that station through the wires and 98 to the relay 85 and contact 110, coils 109, and code bar controlled switch 111 to operate the proper type bar. Thus the circuits through the proper printing coils 30 are closed at both stations to operate the proper type bar. As the coils 109 are energized they draw down clamps 161 extending over the code bars 112 to hold them in the position to which they have been moved by the selector coils, and at the same time the movement of one of these armatures closes the interlock switch 108 which closes the circuit through the coil 104 of the distributing relay 85. This happens at both stations and the closing of this switch 108 by the interlock 109 causes the distributing relay to shift to engagement with the contact 107 and thus close and establish its own holding circuit. At the same time this distributing relay thus transfers the circuit it opens the circuit to the coil of the relay 81 thereby opening the main line circuit and deenergizing the selector coils 93, 94, and 96. It also interrupts the circuit through the code arrestor coils 109 and releases the code bars 112 and allows the switch 108 to open. The code bars 112 are then all returned to their normal retracted position by their respective springs opening the code circuit switch 111 which has been closed. This also, of course, opens the circuit through the type bar solenoids 30 allowing the type bar printer arm to be restored to its normal retracted position. The function of the code bar arrestor 109, 161, therefore is to prevent further movement of the code bars 112 after the correct'printer circuit has been established, and to cause deenergization of the selector coils and the type bar coil immediately after the printer has functioned. The function of the relay 85 is to interrupt the circuit of the selector coils, the type bar magnet or coil and the 'arrestor magnet. Release of the depressed key 22 will allow the distributor relay 85 to return to its normal position by opening the switch 26.

From this operating sequence it will be seen that as the operator depresses any givenkey the operation is automatic for the determination of the proper signal value for establishing the code circuit on both printers, the printing of the character and the clearance of the line circuit and all local control circuits except the coil circuit of the distributing relay 85 at the sending station. It is necessary tohave a different value of resistance 79 connected to each key for each character to be printed, and code contacts to correspond with the movement of the code bar for each increment of resistance placed in the main line circuit.

It should also be noted that operation of the relay 81 at the receiving station serves no useful purpose. Also that the clearing action of the distributing relay 85 at the receiving station is unnecessary, since the deenergization of the main line circuit causes an interruption at both the interlock 91 and the code bar controlled switch 7 teenth key and all above this number which would be from seventeen to thirty-two to thus energize the neutralizing coils 99 in the selector and to operate the printer shift magnet 43. Thus, if we assume there are sixteen code contacts or switches 111 operated by sixteen plungers 129, thirty-two characters of symbols can be printed because each can be used to print two characters. The first sixteen characters would be printed by current values insufficient to operate the relay 163 while the characters 17 to 32 would be printed by current values sufficient to operate the relay and energize the neutralizing coils 99, and printing these characters by code bars 112 repeating the original sequence of positions, but printing a difierent set of characters due to the printer shift operated by solenoid 43. Additional characters may be provided by adding more code bars or more contacts for the existing code bars.

The distributing relay is used to operate the tape feed roller and platen 50. As indicated, one side of the feed operating coil 67 may be connected to a contact 158 in the relay and the other side to the lead 88 from battery 75. Thus when relay 85 is operated by closing of switch 108 the feed will advance the tape. As the relay is operated with operation of the type bar this feed of the tape will take place immediately after the impression is made.

In Fig. 16 is shownan arrangement whereby the full battery current is not on the mainline circuit when the system is not being used to transmit a mesasge. I have not shown the entire sys tem in this figure but only sufficient to indicate the change. Here instead of the hand operated switches 97 I use relatively high resistances 160. These resistances are of such value that when the system is not being used the current over the main circuit is not sufficient to advance the code bars 112 by the selector coils. It will be evident that on depression of a key 22 at the sending station this resistance is shunted by the key controlled switch 80 and the corresponding predetermined definite current value is supplied to the main line circuit to operate the selector inthe manner above described. By this arrangement the main line circuit is maintained closed through the receiving station with minimum loss of battery current and the elements of the apparatus remain in the inoperative position when no message is being transmitted.

This mechanism can be applied to the ordinary telephone circuit so that any telephone subscriber can leave a message at any other subscribers station which is provided with this mechanism. The ciYcuitsfor' doing this are shown in Fig. 18. The local circuit comprising the printing mechanism, the key operated switches with different resistances in series to supply different predetermined definite current values to the line, the selector device, the code bars, the various relays, and type bar operating means at each station is the same as shown in Fig. 15. These stations may be connected through the central telephone exchange 157 as illustrated. The telephone box at each station is indicated at 132 to which is connected the usual ground 133 and the ringing lead 152 and the talking lead 153. There is also located at each station a transfer switch or relay 134 operated by the relay coil 135 connected through the leads 136 and 137 to the battery 75, which circuit is controlled by the telephone hook 138 on which the telephone receiver is hung when the instruments are not in use. The weight of the receiver depresses the hook so that it rests on the stop 139 and is moved away from the contact 140 to'open the circuit through the solenoid coil 135. The transfer switch 134 has two blades 141 and 142, the blade 141 being movable at one end between the contacts 143 and 144, while at the other end it is movable between the contacts 145 and 146.

.The other blade 142 is movable at one end between the contacts 147 and 148 and at its opposite end between the contacts 149 and 150. It is normally held in the position shown by a spring 151 with the blade 141 bridging the contacts 143 .and

145, and the blade 142 bridging the contacts 147 and 149. The lead 152 to the box 132 is connected to the contact 150 and also the contact 149, and the contact 149 is connected to the wire 73 from the battery 74 while the contact 145 is connected with a lead 72 from the selector coils 93, 94, and 96. The contacts 147 and 148 are connected by a ringing line Wire 154 while the contacts 143 and 144 are connected by the talking line wire 155 to the jack plug 156 at the central telephone exchange indicated at 157. These wires are extended on the switch board through .to the receiving station as indicated. The wires stalled as such as indicated on the drawings where the telephone receiver is indicated at 158 and the telephone transmitter at 159.

The operation of calling a station from any given station is as follows:

As in the discussion of Fig. 15, we will assume that in Fig. 18 the left hand station is the sending or calling station while the right hand station is the receiving or called station. As indicated above, the transfer switches 134 are normally in the positions indicated in Fig. 18. In this position the ringing line L2 is completed'from the central exchange 157 to the ground 133 through the switch blade 152 and therefore the central operator can ring the telephone bell at the called station. Now assuming that a party at the left hand station of Fig. 18 wishes to call a party at the right hand stat-ion, the calling party lifts the'130 receiver from the hook at his station. This per- 1 mits the telephone hook to rise and engage the contact 140 thus closing a circuit through the relay coil to a battery '75. This throws the switch 134 at the calling station so that the blade 141 now bridges contacts 144 and 146, while the blade 142 now bridges contacts 148 and 150. This places the telephone at this station on the talk-- ing line Ll completing the talking line to ground 133 and gives the usual calling signal to the operator at the central exchange. The operator plugs in on the exchange board to the called station in the usual manner and as the calling line L2 to this station is completed to the ground 133 by the switch 144 being in its normal position, the call bell is rung at this station in the usual manner. If the party at this station answers, as soon as he lifts his receiver from the hook 138 it rises to close the circuit from the battery 75 to the relay coil 135 throwing the switch 134 to its other position. This movement of the switch breaks the ringing circuit L-2 but establishes the talking circuit L-l as the switch blade 141 bridges the contacts 141 and 146. The conversation can then be continued in the usual manner, talking current being supplied at the central exchange. If, however, the called party does notanswer and the calling party wishes to leave a typed message hecan do so. In doing this, he opens the switch 97 at his station, the corresponding switch 97 remaining closed at the called station. He also replaces his receiver on its hook returning the relay switch at the calling station to its normal position shown. As the called party did not answer, his telephone receiver remains on his hook and the switch 134 remains in the position indicated. There isnow a complete metallic circuit between-the two stations and operation of the keys 22 at the calling station will operate the typing mechanism at the two stations as described above. After transmission of the printed message is complete the calling party can inform the operator at the central exchange and the lines cleared for another call in the usual manner.

Having thus set forth the nature of my invention, what. I claim is:

1. An apparatus for transmitting messages between stations comprising an electric circuit connecting said stations, controlled means at the sending station for supplying signals of predetermined definite current values to the circuit, a selector unit at the receiving station connected with said circuit and comprising a plurality of magnetically operated means having difierent characteristics to respond to said current values, a series of different circuits controlled by said selector, a relay controlling said latter circuits, and a magnetically operated interlock connected with the selector controlled circuits operated when the selector has closed the circuit corresponding to the signal value to operate said relay to open the selector closed circuit to restore the system tonormal condition for the next signal.

2. An apparatus for transmitting messages between stations comprising a main electric circuit connecting said stations, a plurality of local circuits corresponding to the symbols to be produced, a recording means controlled by each circuit, a selector unit connected to the main circuit comprising a series of solenoid magnets operating control elements of difierent characteristics responsive to different signals of definite current values, a plurality of keys, means controlled by the keys for supplying signals of predetermined definite current values to the main circuit to operate said selector, a relay adapted to open the circuits to the selector and the recording means, an interlock for closing the circuit to said relay when the selector has closed the recording circuit corresponding to a signal value of a given key, and means controlled by said key for energizing the local circuit.

3. An apparatus for transmitting messages between stations comprising a main metallic circuit connecting said stations, a plurality of keys for supplying signals of predetermined definite current values to said circuit, a control circuit controlled by each key, a plurality of printing devices operated by the control circuits, a selector comprising a plurality of solenoid coils connected in the main circuit, an armature operated by each coil against springs of differing characteristics, a code bar operated by each armature, a plurality of plungers arranged to be operated in succession by each code bar, and control contacts for the respective printing circuits controlled by said plungers.

4. A device for transmitting messages composed of a series of signals between stations comprising a single electric circuit connecting the stations, means at the sending station for supplying a plurality of signals of difierent predetermined definite current values to the circuit and of one current value only for each signal, and recording means at each station connected with said circuit giving an identical and simultaneous response at both stations to each current value.

5. An apparatus for transmitting messages between stations comprising an electric circuit connecting said stations, means at the sending station for supplying signals of predetermined definite current values to the circuit, a recording means at the receiving station including a plurality of printing devices adapted to print in upper and lower case, electrically controlled means for feeding a tape past said printing devices and shifting it so as to print in upper or lower case, a selector comprising a plurality of coils con nected with the main circuit, aplurality of armatures operated by said coils, a code bar operated by each armature, control'circuits for the printing devices, a plurality of code contacts controlling said latter circuits and operated by said bars, neutralizing coils for the first mentioned coils, and a relay operating only on a current equal to a given value to energize the neutralizing coils and operate the tape shift.

6. An apparatus for transmitting messages between stations comprising an electric circuit connecting said stations, controlled means at the sending station for supplying signals of predetermined definite current values to the circuit, a selector unit at the receiving station connected with said circuit and comprising a plurality of magnetically operated means having different characteristics to respond to said current values, a series of difierent circuits controlled by said selector, a relay controlling said circuits, printing devices controlled by said circuits, a printing tape associated with the printing devices, a feed means for the tape controlled by said relay, and a magnetically operated interlock controlled by said selector to operate said relay.

'7. An apparatus for transmitting messages between stations comprising an electric circuit connecting said stations, means at the sending station for supplying signals of predetermined definite current values to the circuit for different symbols, a selector unit at the receiving station connectedwith said circuit and comprising a plurality of magnetically operated means having different characteristics to respond to said current values, a slidable code bar operated by each of said magnetically operated means, a plurality of contacts 135 operated in succession by each bar arranged to close and open immediately as the bars pass over them, and recording means controlled by said contacts.

8. An apparatus for transmitting messages be- 14; tween stations comprising an electric circuit connecting said stations, means at the sending station for supplying signals of predetermined definite current values to the circuit for different symbols,

a selector unit at the receiving station connected with said circuit and comprising a plurality of magnetically operated means having different characteristics to respond to said current values, a plurality of recording circuits, control contacts for said circuits, a slidable code bar operated by each of said magnetically operated means, and a plurality of said contacts. arranged to be operated in succession by each code bar in its sliding movement.

9. A device for transmission of messages between stations comprising an electric circuit connecting the stations, means at the sending station for supplying a plurality of signals of different current values to the circuit, a plurality of selector coils at the receiving station energized by said currents, a code bar arranged to be shifted by each coil an amount depending on the value of the current in the coil, a plurality of switches controlled by each code bar in succession as the bar is shifted, and a recording device controlled by each switch.

10. In a device for transmission of messages between stations comprising an electric circuit connecting the stations, means at the sending station for supplying current to the line for the signals to be transmitted, a selector coil in the circuit at the receiving station, a code bar adapted to be shifted by said coil different amounts according to the current in the circuit, a plurality of switches operated in succession by the code bar as it is shifted and a recording device controlled by each switch.

11. In a device for transmissionof messages between stations comprising an electric circuit connecting the stations, means at the sending station for supplying current to the line for the signals to be transmitted, a plurality of selector coils at the receiving station in said circuit, a movable code bar for each coil adapted to be shifted thereby in one direction, a resilient means tending to shift each bar in the opposite direction, a plurality of switches operated in succession by each bar as it is shifted, and a recording device controlled by each switch.

12. In a device for transmitting messages between stations, an electric circuit connecting the stations, a plurality of selector coils in the circuit at the receiving station, an armature for each coil, 2. slidable code bar operated in one direction by each armature, a resilient means tending to shift the code bar in the opposite direction, a plurality of plungers at one side of each code bar to be operated in succession by the bar as it is shifted, means normally holding the plungers in the path of movement of the bar, a switch controlled by each plunger, and a recording device controlled by each switch.

VERNON M. BUGGE.

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