US2262567A - Teletypewriter indicating system - Google Patents

Description

Y- c. J. VOTAW 2,262,567

- TELETYPEWRITER INDIC I XTING SYSTEM Filed May 25, 1940 a I 2 Sheets-Sheet 1 2/6 RECT- 222 I 3 226 228 INVENTOR By C. J. I/O TAW AT TORNE V NOV. 11, 1941. Q J. VQTAW 2,262,567 TELETYPEWRITERINDICATING' SYSTEM Filed Ma 25, 1940 2 Sheets-Sheet 2 FIG. 3

lNl EN TOR CiJ. V0 734 W Brig J2 ArroR/vE Patented Nov. 11, 1941 UNITED STATES,PATENT OFFICE TELETYPEWRITER INDICATING SYSTEM Clarence J. VotawsFo rt. Wayne, Ind., assignor to American Telephone and Telegraph Company, a. corporation of New York 7 Application May 25, 1940, Serial No. 337,167

' 3 Claims. ,lcl. 178-2) This invention relates to printing telegraph systems and, more particularly, to improved means for infallibly determining whether a teletypewriter motor located at a distant station'has actually been stopped in response to the transmission of a stop signal. I

Various arrangements have been designed heretofore for acknowledging the reception of a stop signal but such arrangements d not provide an infallible indication that the teletypewritermotor itself has actually stopped.

Consequently, it is an object of this invention to provide a teletypewriter system with means for infallibly indicating that the transmission of a stop signal has failed to stop a teletypewriter motor located at a distant station.

It is also an object of the invention to provide a teletypewriter system with improved means for indicating that a teletypewriter motor at a distant station is running and operating its teletypewriter.

In accordance with the invention; a printing telegraph system, whether polar or neutral, provides the control station with a jack in series with the line. To obtain an indiction of the condition of a teletypewriter motor at a distant station, an attendant at the control station connects an indicating device, such as an ammeter, into the line by plugging into the jack. Then, by employing any suitable means to change the normal marking condition of the line to a spacing condition, the line will be opened by the break contacts in the teletypewriter at the distant station if the motor at that station has not been stopped. This opening of the line will be indicated to the attendant at the control station by movement of the needle of the ammeter. However, if the teletypewriter motor has been stopped, then the break contacts will not be opened in response to the spacing condition of the line and there will be no fluctuation of the ammeter needle. If desired, an audible signal device may be either optionally or additionally inserted into theline forsimilar operation.

These and other features of the invention will be more fully described in connection with the following detailed description of the invention in Fig. 2 represents the invention applied to a neutral printing telegraph system; and b Fig. 3 shows the mechanism for'opening the break contacts whenever the blankfunc'tion lever 55 1,931,672 granted October 24,

distant station is 3 the left and is shown to include a teletypewriter T1 comprising a printer magnet l, sending cone tacts 2, and a break key 3. Teletypewrite'r T1 is connected to the contacts of a jack 4 which is connected to the operating winding of a polarized relay 5 and then to positive battery 6. Battery 6 is also connected through the biasing 'winding of relay 5 to ground. A dummy plug 1 is provided for insertion into jack 4 for opening the circuit leading from battery 8. to battery 6. "The armature of relay 5 is designed to fluctuate between its contacts to apply current from either battery 9 or [0 through a variable resistance H and a noise killer I2 and then over the contacts of jacks I3 and 25 to the communication channel. represented by line M. An ammeter I5 is designed to .be connected into the communication channel whenever plug I6 is inserted in the jack 13. A relay 26, which controls a bell 21, 15 connected to a plug 28 which is adapted for insertion into jack 25. i

A distant station, which may be a subscriber station, is represented at the right in Fig. 1 and is illustrated as comprising a telety e riter T2. The teletypewriter T2 is shown as a receivingonly machine and is equipped with a printer magnet l'l, a motor l8, stop-contacts l9, and a set of break contacts 46 which are shown in more detail inFig. 3. The communication channel is shown to extend from line I4 through a polarized relay 2| and then through the break contacts 46 to ground. A suitable source of power supply 22 is provided for operating the motor I8 and for energizing the rectifier 23 which supplies current over the armature of relay 2| to the printer magnet A manually operable switch 24 is provided for enabling the subscriber to disconnect the power supply 22 from the motor l8. The rectifier 23- is usuallyoperating continuously, but a manuallyoperable switch 40 is provided for enabling the subscriber to disconnectthe. power supply 22 fromthe rectifier 23 when desired.

In operating the system shown in Fig; 1, it will be noted that, in this embodiment of the invention, the communication line is normally closed with negative current from battery 9 passing over the armature of relay5, out over line H; through the winding of polarized relay 2|, and then over the break contacts 46 to ground. If desired, some suitable means, such as that disclosed. in Patent Morton et al;, may be employed for enabling an attendant at the central office to start the teletypewriter motor l8 at the distant subscribers station. The disclosure of this Morton et al.

Patent 1,931,672 is incorporated herein by refer ence as a part of this specification. In accordance with the Morton et a1. disclosure, the subscribers motor is started by means not shown in the drawings in response to an'openingof the communication line l lfor a preassigned interval of time followed by a closure of line M. The armature of relay 5 will now fluctuate between its contacts to apply current from either battery '9 H Thesi'gnificant current or it to the line I4. p v variations sent out over line I fl 'by'ithe fluctuations of the armature of relay 5 comprise-1ee1arjsigfie1s which correspond to the permutation code signals formed by the sen-ding contacts 2,

After communication has ended, or at end I i of a business day, an attendant may wish-to stop the-te e ew iie mor t. at t e istant. s b- "s'cr'ibers stationf This can be done by transries" withfthe' 'line circuit. e attendant then inserts the dunnnyplugfinto jalckq there-,

by opening thecircuitfroni the Central office tel'etypewriterffl to the polarizedeijel ay 5 The opningof this circuit permits the biasing wind i of i la iz d flayifto more hearmature i i I Iar s'ra s ntat t a ly/Pos ive ser ne c re t r l9 9 t e line.- 1 e'u'it. This positive spacing currentgon the line circuitcauses the polarized relay 3i alt-the; dis- W n 9 'mQ it armature. to its erasin 'contactl'lf u k u IJ-T l t r h m enstqeesd;e the cur-renttotheline circuit, V a w fw' nflam mpr per. ad u tment ji helw w a or er a ther ea on motor 18 failed to stopin response t QLtlilQ stop signal'fitwill be operating theteletypewriter Tz w e t e spacing ur e p PPl ed Q th nev q t The mon pa in urrent n the line .will now have the same effectas a so-called 'i l' i na n ll er se h et iemech= b ii t6 e eb li at biil oi' specific' accordingly, the'fir st phase of the motor starting anis'm in theteletypewriter Tz'tosel mhe blank fu'rfctionlever L03 in, the mariner described in November ai sseese to s. lv e ce a1; Both of tl'i'se"Morton etal. patents areincorporated he i r e s ar p rt; o t isisne i-fic zb eied s-elesg bea in h MOI: i f FQ .efisct h perat n of: t e contacts was. will be describedemorefully 'o'fftlieibreak contactsidfi opens theiline cira'ftl "inconnection'with FigTheopen e l il fi fli l e 3 w l come:

u l y penin 'the ammeter I5. This provides a visible indi cation to the attendant at the central ofiice that the transmission of the stop signal failed to stop 7 the motor H3 at the distant station.

As will be described hereinafter, the break contacts 46 only open momentarily and then close thereby'causing the needle of ammeter 15 to return to its initial position. However, since spacing current still remains on the line, the

selecting mechanism in the subscribers teletypewriter T2 will again select theblank function lever I03 for momentary operation to again open the break contacts momentarily to again move the needle of the ammeter [5. This causes a continuous fluctuation of the needle of am- Thecentral ofiice attendant then withdraws plug 16 rom c I3 and plug 1 from j 4 thereby restoring marking current from battery are the line circuit to discontinue the selection of the blank function lever 33 The attendant r smit aimth stop ignal and test 1 the j '3 e eie- If S r es 7 .v top na s. fails to stop motor IS, the attendant at the central ofiice may communicate by any convenient means, such as by telephoneywith the distant subscriber to inform him, that the motor 18 is running.v The subscriber can; then go to the teletypewriterTz and stop the motor l3 by man serting plug 28 into jack-25, to connect relay 26 into the line circuit. The line current energizes relay '26 which operates itsarmature. The attendant closes the manual switch 2!; to prepare a circuit for current from battery 30 to operate the signal bell 21. When the break contacts 46, open the line'circuit, relay 26- releases its armature. This completes the circuit for currentfrom battery 30 tooperate bell 21 to provide thecentral ofiice attendant'with an audible signal, .If: the mQtQI has Stopped in response to the H stopllsignal, aswill bev evidenced by steady defiec;

tion of ammeter [5, or no, responseofsig-nal bell 21; the attendant may remove plugs lfifand '28 b e l 19i remove umm l s 7 if i618: ypewriterTei to remain in outeof-serviceor non-responsive condition for a period of time. The reason for this that the spacingcondition into whichthe line is placedp fi aratory tow test-1 ingfor stopping of the motor corresponds to the condition which is establishedas the first phase of startingthe motorby remote control, and,

function as disclosed in Patent 1,931,672 isper-t' formed, the function being'incomplete, however. If, after the testgtheline is'restored to marking condition, the second phase of the motor starting function will be performedand the motorwill. ber'estarted. In order to avoid such restarting of the motorthe line shouldebe left in thesp'acing condition until the next transmission period, and this is the normal out-of-serviceconditior for systems of the type shown inFig. 1. a

The neutral printing telegraph system shownin; Fig, 2 'c omprises at the left a controlstation, such as a central ofiice, which is provided with a teletypewriter T3 having a printer magneti'fll,

sending contacts 202, and a break key 203. The

'teletypewriter T -isconnected over the inner left set of-contactsof control key 220 tolneg'a v tive markSng battery'ZOJS. Positive battery 210' is connectediover the inner'right set ofcontacts .S W-l 1.4.1 9. dis onn t. the

power supply 22 from themotor 18;;

An additional, or optional indication may be I obtained by thecentral ofiiceattendant by inof control key 220 to the contacts of jacks 2I3 and225. An ammeter 2 I is connected to a plug 2I6 which is adapted for insertion into jack 2I3. A relay 226, which controls a bell 221, is connected to a plug 228 which is adapted for insertion into jack 225.

A communication line 2I4 extends from the central ofiice to a subscribers station shown at the right in Fig. 2. The subscribers station is shown to be equipped with a receiving-only teletypewriter T4 having a printer magnet 2I1, a motor 2I8, stop contacts 2I9, and a set of break contacts 246 similar to the break contacts 46 shown in Fig. 3. The subscribers station is also provided with a suitable source of power supply 222 for operating the motor 2I8 and for energizing the rectifier 223. Rectifier 223 supplies current to the printer magnet 2 I 1 and also to the biasing winding of polarized relay 22I which has its operating winding connected into the line 214. A manually operable switch 224 is provided for enabling the subscriber to disconnect the power supply 222 from motor 2IB. Another manually operable switch 240 is provided for enabling the subscriber to disconnect the power supply222 from rectifier 223.

The system shown in Fig. 2 is also equipped with means, similar to those disclosed in Morton et'al. Patent 1,931,672, for enabling an operator at the central oflice to start the subscribers motor 2I8 by opening the normally closed line 2I4 for a certain length of time and then closing it again. After motor 2I8 has been started, the operator at the central oflice operates the sending contacts 202 to originate the transmis sion of permutation code signals out over line 2I4. In this connection, it is to be noted that the line circuit is normally closed by current passing from negative battery 209, over key 220, through the teletypewriter T3, out over the top side of line 2I4, through break contacts 246 at the subscribers station, operating winding of relay 22I, back over the bottom side of line 2I4, contacts of jacks 2I3 and 225, key 220, and then to positive battery 2 I 0. Permutation code signals composed of significant current variations can now be sent from the central oflice out over line 2I4 .to' the subscribers station. At the subscribers station, the significant current variations cause the armature of polarized relay 22I to fluctuate between its marking and spacing contacts thereby causing corresponding variations in the current passing through the printer magnet 2I1.

When the operator at the central ofiice wishes to shut down the apparatus at the subscribers station, a stop signal is transmitted which accomplishes the functions of the stop signal described in the Morton et al. Patent 1,931,672 since it is understood that the teletypewriter T4. is equipped with the features disclosed in the Morton et a1 patent. The transmission of the stop signal effects the opening of the stop contacts 2I9 thereby opening the circuit from the power supply 222 to the motor 2I8.

To detect the failure of the transmission of the stop signal to accomplish its purpose, the attendant at the central ofiice inserts plug 2I6 into jack 2I3 thereby connecting the ammeter 2I5 in series with. the line 2I4. The attendant then inserts plug 228 into jack 225 to connect relay 226 into the line circuit and closes the manual switch 229. The central office attendant next operates the control key 220 which connects the positive'battery 2 I0 over the outer left contacts of key 220 to the top side of line 2I4 and connects battery 209 over the outer rig-ht contacts of key 220 to the bottom side of line 2 I4, Thus, the operation of key 220 reverses the direction of the flow of current in line 2 I4. The line current energizes relay 226 which operates its armature to open the circuit from battery 230 to the bell 221. v

At the subscribers station, the reversal of current flow through the operating winding of polarized relay 22I assists the biasing current in moving the armature of relay 22I to its spacing con tact. This opens the path from rectifier 223 through the printer magnet 2I1. If motor 2I8 has been stopped by the transmission of the stop signal, there will be no reaction to this movement of the armature of relay 22 I.

However, if the stop signal failed to stop moto 2I8, then the teletypewriter equipment will be running at the subscribers station. In this event, the movement of the armature of relay 22I to its spacing contact will be registered in the teletypewriter T4 as a blank signal. This will effect the selection and operation of the blank function lever I03 which will, in turn, effect the momentary operation of the break contacts 246 in the manner described in the Morton et al. Patent 1,980,284 mentioned above. The opening of the break contacts 246 opens the line circuit therebycausing the needle of the ammeter 2I5 to move. This provides a visible indication to the central office attendant that themotor 2I8 at the distant station is still running and operating the teletypewriter T4. At the same time, the opening of the line circuit causes relay 226 to release its armature to close the circuit from battery 230 to the bell221. This causes the operation of bell 221 to provide an audible signal to the central oifice attendant. I

The central ofiice attendant may then withdraw plug 2I6 from the jack 2I3 and plug 228 from jack 225 and restore his control key 220 to its normal condition shown in Fig. 2. He may also open the switch 229 to discontinue the operation of bell 221. The attendant may then transmit more stop signals and test the motor 2 I 8 again. If the-attendant detects that the stop signals have failed to stop motor 2I8, he may telephone the distant subscriber to request him to manually open switch 224 to disconnect the power supply 222 from motor'2l8.

If the test indicates that the motor at station T4 had stopped as desired, he may remove plugs 2I6 and 228, leaving key 220 in the operated condition to maintain the communication circuit in spacing condition, which is the normal out-of-service condition for a system of the class disclosed in Fig. 2. Thus the completion of the motor start operation will be estopped.

The mechanism for opening the break contacts 46 and 246 in response to the selection and operation of the blank function lever I03 is illustrated in Fig. 3 which is somewhat similar to Fig. '1 of Morton et al. Patent 1,980,284 mentioned above. As is described in this Morton et al. patent, the transmission of a so-called blank signal effects the selection of the blank function lever I03 in the receiving teletypewriter which may be either T2 or T4. Since a blank permutation code signal comprises .a succession of spacing impulses, as is described in the Morton et al. patent, the application of spacing battery to the communication line instead of marking battery will simulate a blank permutation code signal. Thus, the'substitution ofspacing 'batterye nses a s cce on o blan signal unc ion lever I03 caus s i s xtension arm 1 o ti t arm o T-leve I08 d wnward. moveslever I08 counter-clockwise to its operated position where it is held by the spring washer 114. In rotating, arm N2 of lever I08 shoves. T- ver 89 and in rmedia e l ver 1.24 to the left. In moving laterally to the left, intermediate lever I24 rotates clockwise slightl .due to the pull exerted by spring -I3I, to cause its en p rt 8 to beara ainst he sid of t extension arm I06. I I

c mple es h first cycl of ions as the blank function lever I03 is now restored to its normal position by the function bail I38 thereby elevating the extension a m I95. T-lever I08 is held in its operated. position by the spring washer H4 but spring .831 i now abl o pull the intermediate lever 124 further in a clockwise direction, because the elevation of extension arm I06 ha disen d arm "36 from he tip of :the end portion I28 of lever L24, This permitszthe intermediate lever I24 to rotate sum-,- ciently tofiswing its end portion 123 into the d wnward path of the extension arm I06 of the blank function lever I03,

Since spacing battery still remains on the line circuit, the selector vanes 31 again set up. a

blankcode s nal to again sele t the blank function lever .I 03 for operation. The resultingdownward movement of extension arm I06 will now be intercepted by the end portion 1-28 of the intermediate lever I24. Lever I24 will now be urged downward to impart rotative motion a counter-clockwise direction to T-lever 89 about its pivotalconnection to lever I08, The consee 'quent downward movement of arm I I6 .of T -lever 89 will now impart through its laterally disposed portion I, which overlaps a laterally disposed portion "88 of arm 86 of lever 5.0, clo kw e motion to lever 56. This clockwise rotation of lever 50 causes its vertical arm..8'l with its laterally disposed arm 9I to moveto the right a suflioient distance to openthe break contacts 45 thereby opening the line circuit. In response to the opening of the line circuit by break contacts 46,

. the needle of the ammeter at the central otfice will move to indicate to the central ofiice attendant that the teletypewriter motor at the dis:

tant. station is still operating.

The-opening of the line circuit is only momentary because the function bail I38 restores the blank function lever I03 to its normal position thereby elevating its extension arm lot. This removes the pressure of arm I65 on the end portion I218 of the intermediate leverin thereby permitting spring I3-I to pull both the inter.- mediate lever I24 and the T-lever 89 clockwise to remove the downward pressure of portion II,

I of arm I16 of lever 89 on portion 68 of, arm 86 of lever 50. This allows spring 93,, which is attached to the laterally disposed portion .92 of arm I2 of lever 50, to restore lever 50 to its former position. The counter-clockwise movement of lever 50 causes its vertical arm 8'! to move to the left to allow the break contacts 45 to close the line circuit.

h conn ction it s to beno d that since the teletypewriters T2 and Trare of the IBCBiV-r ins-only type, they have been modified to :the extent that the latch II, spr ng 82 and the keys 4,9 and 69, allshown in Fig.6 of Morton et al. Patent 1,980,284, have been removed.

Since spacing current still remains on the line circuit, another blank signal will be set up .by the ,selectingvanes 31 to again select the blank function lever I03 which goes through the cycle of operations just described above to again open the break contacts 46v momentarily. This opens ing and closing of the break contacts 46 and the line circuit continues .until either the motor of the subscribers teletypewriter is stopped or'until the spacing battery is .removed from the line circuit and the. normal marking battery a plied thereto, V

It is to be understood that various modifications may be made in the circuits and apparatus shown in the drawings. For example, various other types of printing telegraph systems may be employed and other types of mechanical apparatus in the printersmay be used. Also other types of signaling devices other than an ammeter or signal bell may be used if desired. Consequently, it is to be understood that the above described circuits and apparatus have been shown for the purpose of illustrating the principles and'features of operation of the invention and that the invention is to be limited only by the claims appended hereto.

What is claimed is:

1. A printin tele ph system, compri ing in combination a control station, a distant station having a teletypewriter and a motor for operating the teletypewriter, a communication channel for connecting the two stations, means for applying current to the communication channel, operating means for operating the motor, means for transmitting S nificant current variations over the communication channel from said control statlon to the distant station, means for stopping the motor in response to the reception by the teletypewriter at the distant station'of certain .preassigned current variations transmitted from said control station, break means for opening the communication channel at the distant station, operatingmeans for operating said break means in response to a certain. variation of the current in the communication channel only when said motor is operating, an indicatorat the con.- trol station, and means for connecting said in.- dicator into the communication channel for in..- dicating an opening of the communication chan nel by the operation of the break means.

. 2. A printing telegraph system comprising in combination a first station, a second station hav. ing a teletypewriter and a motor for operating the teletypewriter, a communication channel for connecting the two stations, means for normally applying marking current to the communication channel, operating means for operating the motor, means for transmitting significant current variations over the communication channel from the first station to the second station, means for stopping the motor. in response to the reception by the teletypewriter at the second station of certain preassigned current variations transmitted from said first station, means for applying space ing .current to the communication channel in,- stead of marking current, break means for open.- ing the communication channel at the second station, operating means for operating said break transmission'channel connecting said stations, 0

said stations being provided with apparatus including a teletypewriter driving motor at one station having a normal condition in which said motor is stopped, means at said one station for controlling the operation of said motor, and means at the other station for indicating independently of said motor controlling means an abnormal running of said motor.

CLARENCE J. VOTAW.

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