US1842478A - Telegraph system - Google Patents

Description

Jan. 26, w T REA TELEGRAPH SYSTEM Filed April 23. 193].

INVENTOR ATTORNEY Patented Jan. 26, 1932 www STATES PATENT orricr: f

WILTON T. NEA, or nLnsHrNcr, NEW YORK, AssreNOR 'ro AMERICAN `TELEPHONE AND y 'rnrnsnnrn cOMPANmA- CORPORATION or Nnw YORK TELEGRAPH SYSTEM Application led April 23,

This invention relates to telegraph systems and, particularly, to breaking arrangements for'such systems. y In'telegraph systems" such als" duplex systems, it is often desirable for an Operator at one station `to break7 in on the line or to interrupt the operator who may be sending from a distant station in order to obtain Control of the circuit. `It is, in general, the

104 object of this invention to provide improved arrangements `for this purpose by providing at a telegraphl` station arrangements whereby the receivingrelay is maintained continuously in the marking condition whenever the 15, sending relay is in the spacing condition, thus rendering the incoming signals to the.. re-

ceiving relay inetectual` to the localcircuit and allowing a-spacing'signal to be sentto the sending operator, the spacing signal causing like `battery polarities tobe connected to both ends of theloop circuit and vinterrupting the sending.

The breaking `feature of the telegraph system is generally accomplished by a break relay which forms equipment furnished inaddition to the sending and receiving relays of the telegraph repeater. Another object of this invention is to do away with this additional equipment, i. e., the break relay,

. and to "accomplish the purpose voi? such a relay by means of the sending and receiving relay circuits. f

While this invention "will be pointed out with particularityin the appended claims, the inventionitself, both as to its Jfurther objects and features, will ber better understood from the detailed description hereinafter following whenread in connection with the accompanying drawingr which shows oneI embodiment of the invention given merely for the purpose of illustration.

\ lIn the drawing there is shown one terminal oi'4 a carrier telegraph channel at which there is a line L1 over which signals coming in from a distant station `may be received and a line L5 over whichsignals may be transmitted to a distant station. The pulses of carrier current incoming over line L1 flow through a. 5 receivingfilter F1 and an amplifier A and are t rectified' by a detector tube V; It will be 1931. serial No. 532,362.

apparent that pulses Vofdirect current oorresponding to the received pulses of alternating current will appear inthe plate circuit Of detector tube V, in which are included the main` winding W2 of a polar receivingzrelay R1 and the primary winding W1" of a kick transformer T2.

Each pulse of direct current flowing through the winding W2 tends to move `the armature of the receiving relay R1 to its marking contact M. lWhen ground is applied to the movable contact P1 of the key K1, either through the fixed Contact P2 or through the fixed contact P5 `and the armatureand marking Contact M of the sending relay' R2, current lows from the batteryv B3 through the winding W2 over the'resistance Z2 to ground, current also iiowing from battery B2 through the winding W5 over the resistance Z2 toground. The current in the winding W5 tends to move the armature toward the marking contact M with a force equal to half that produced by the winding W2. The current in the Winding W5 tends to move'the armature toward the 'spacing contact S with a force equal but opposite to that producedby winding W2. Itis thus apparent that the combined effect of windings fr and W5 tends to movethe armature, toward the spacing contact S Witha forcev equal to one-half the force which the current in winding W2 exerts toward the marking contact M. It will be seen, therefore, that with normal current flowing through thewinding W5, the armature of the receiving relay R1 will move back and forth bewteen the marking contact M and the spacing contact S in accordance with ther telegraph signals impressed upon the winding W2 The eiect of winding W3 is merely to accelerate the motion of the armature. The rise and decay of current flowing through the winding Vl of the kick transformer T2 induces in its winding W5 currents which, flowing through the winding W5, aid the signalingcurrents in moving the armature.

For half-duplex operation the key K1 is operated, thereby connecting the contact P1 P4 and disconnecting contacts P7 and P2.`

In this case the armature of the receiving relay R1 is connected to the local loop circuit L2, which includes the winding N7 and T8 of a polar sending relay R2, a key K2, a sounder N1, a battery B2 and the resistances Z5 and Z6. The batteries B2, B7i and B7 are of susbtantially equal voltages and in fact they may be the same battery. `With key K2 closed, as will normally be the case when the local operator isreceiving signals and when the armature of the receivingrelay R1 is on its marking contact M, current will flow from the battery B.i through the sounder N1', the' key K2, the resistance Zandthe Winding `W7, to the battery B6 and current will'iiow from ground` through the resistance Z6k and, the Winding. W2 vto *the battery- B6. Thecurrent through-winding vlsmill tend to movethe armature of the sending relay R2 to its-.spacing f contactl S andv the current through wind'- ingjVV'7.` will tend.- to move s-aid.ar1natureto its marking Contact M with tWicethe'orce exterted by windingA WS. /Vhenthef armature ofthereceivingrelay R1 is--onits-spacing contact S, currentwill flow from the-battery B7 through; the winding VS andI the resistance-Z2 to ground. 'llhiscurrent4 will tend to move thearmaturero--thesending relay B2j to its; marking? contact M1. No current will; liowthrough the; circuit including4 the Winding/V7,.the resistance Z5, .the key K2 and the 'sounder N1, Ysincebatteries-B7 and-.Bgk are mutually.. opposed., It Willthus be-apparent thaty asthe armature of thereceiving relay R51` alternates between itsv marking; and, spacing contacts-.in,accordance with l received/telegraph signals-,pulses of current will flow through the sounder Nhoperating iti. in .accordance with said-signals.v However, itis to be noted that'- the operationofthe armature ofthe receiving: relay will not' operate the sendingrelay R2 when.the key K2 is closed since the -winding'VV7 and NVS are then-in balancecl-.relationwith; respect to the armature of the receiving relay R7 vWhen the armature ofv the receiving, relay R2v is` at rest. ony its mar-king'contact M, as will normally bethe case whentheoper'- ator. at the local station.is-transmitting signals, current from-the batteries B12 and B6 whichare serially-aiding, will flow through the windinglVT of the sendingfrelay R2. As stated ,here-inbefore, Vthis current Willtend to movefthe-armature-of said relay to its-mark- "i" ing contact M. Current will iiow from the battery-BG vthrough the winding, W2 and the resistance ZG to ground, and this-current will tendftounove the armature of the-sending relay B2 to its.- spacing Contact Sl with half the force exerted.byfthecurrent through the winding 77. It will be apparent that the operation ofthekey- K2 willfinterrupt the current: throughtheuwindingfvlh and will i causev the'armature o-ffthe sendingV relay R2 to alternate between `its-1narki'ng and spacing contacts in accordance With the telegraph signals sent by the key K2. Said armature will alternately open and close a short circuit across the output of the alternating current generator G and will thus cause pulses of alternating current corresponding to said telegraphsignals to flow through the sending iilter F2 and over the line L3 to the distant station. The operation of the sending relay armature also alternately'connects to ground and disconnects from ground the circuit which includes the neutral sounder N2, the resistance Z7 and the battery B5, which is of the samevoltage and polarity as the battery B3 and'may, in fact, be the same battery. A resistance Z2.may, if desired, be use'd'to shunt the sounder i i2. The sounder N2 is caused to operate in4 accordance with the transmitted signals, as .described hereinabove. thev repeater station and its purpose is to allow the repeater attendant to .readthe outgoing signals.

Thevcurrent through the winding W5 oi the receiving relay R1 will now be dependent upon the positionof the armature of the sending relay R2, this current being`v substantiallyv Zerowhen. saidf armature is not` connectedto its-- marking contact-7M. Hence, it

will beapparent that when the armature of the sending relay R2 yis-onitsi spacing-,contact S,,the current through the winding-*W2 will cause the armature of the receiving-relay R1 to remain-on its marking. contact. M irrespective of; the pulses ot current. lowing thru Winding 72. If this were not. so, i. e., if the operation of receiving relay R1 Were independent of the position of the armature' ot the sending relay. R2 and if the operator should open'the key-K2 to breakthe distant operator while signals were being received by relay Rhitf would be seen that the sending relayfR1 might be operated by these incomingfsignals, as reversalsof. current would How from the armature of the' receiving relay through the winding l/VS of the sending relay R2 to ground and the current through the winding W7 would be substantially` zero. This-might cause a retransmission of signals back to the sending operator over the line L5, for a periody of time dependent upon the length of thefcircuit. In otherv words, a chattering or disturbance might take lplace on the line which would prevent a clean and effectual'break fromftaking place.

However, as stated above, when=the operator opens the key K2 to break the incoming signals, the armature of the sending relay R2 will move to its spacing contact S. The current through the winding W5 of the receiving relay R7 will drop to Zero and hence the current through the Winding 7.2 will maintain the armature of the receiving relay R7 on its marking contact M irrespective of the effect of incoming signals on theWindingWV2.

The sounder-'N21nay be locatedf at:

Current Will `thenviioW throughfground, the

resistance Z6, the Winding TV3, the contact P2, the contactP3, the receiving relay armature,

`the marking contact `M1 andthe 4battery B3,

. Thus, it is seen that Whenthe key K1 is operated, theloop L2 and the equipment at the repeater station, including the receiving and sending relays R1 and R2, respectively, are interconnectedfor half-duplex telegraphy as stated hereinabove. The operator at the loop L2 may transmit signals by operating his key K2 and pulses of alternating current will, accordingly flow over the circuit L3. l/Vhen the operator at the loop desires to receive signals, he Will close hisY key K2 and pulses of alternating current received over the circuit L1 Will be registered by the sounder N1 athis loop. The operator at the loop may obtain control of the circuit extending to the distant station, While signals are incoming, by opening his key K2. Irrespective -of incoming signals, this Will cause a spacing `signal to be transmitted to the distant station which Will interrupt the transmission of signals by the operator at said station by connecting like batteries to both ends of the distant loop. No break relay is required in this half-duplex telegraph system. The features of the break relay aresupplied by the circuits attached to the receiving and send-` ing relays R1 and R2, respectively. Moreover, the sounder N2 at the repeater station is continually operated and will register all signals transmitted by the local station.

The key K1 may be placed in its normal, unoperated position to provide a full-duplex telegraph circuit. The loop L2 Will then be the sending loop and the loop L,L the receiving loop. The key K2 at the loop L2 will be the essential element required for the transmission of signals over the Vcircuit L3 to the distant station. The sounder N3 Will be the essential element of the loop Lirfor receiving signals over the circuit L1 from the distant station. A key K3 may, if desired, be inserted in series With the sounder N3 at the loop L2. Since the properties of a breaking arrangement are obviously not required in a full-duplex system, the circuit including the Winding W3 of the receiving relay R1 is so arranged that current lows continuously through said Winding when the key K1 is unoperated. The resultant effect ofthe Windiings W4 and W3 Will then besuch as to tend to operate the armature of the receiving relay Rl to its spacing contact S. Thus the combination oi the windings 72 and W3 will serve as a biasing Winding for the receiving ture of the relay Rlthrough the contacts P3 and P3 of the key K1, and a battery B3, which may, if desired, be located at the repeater station, Will be in series With the loop L2. `When the armature of the relay R1 closes its marking contact M, the batteries B3 and B3 Will `bein series with each other and their eii'ects `Will be additive, thereby providing a substantial current through the sounder N3 of the loop L4. This current will create an audible signal at the loop L2. When the armature of the relay R1 closes its spacing contact Sythe batteries B7 and B3 Will then become connected in series relationship, and inasmuch as their voltages are substantially equal and their polar-ities opposite, practically no current Will i'iovv through the sounder N3 at the loop L4. Consequently, the sounder N3 will be unoperated, thus registering a sp acing signal. "Thus, it Will be apparent that the sounder N3 at the receiving `loop L2 will follow the signals received over `the circuit L1.

While the key K1 remains in its normal,

unoperated condition for full-duplex signaling, the battery B3 Will be connected through contacts P3 and P3 to the apex J of the balanced` loop L2. ,A ldeiinite current will flow unidirectionally` through the Winding W3 of the relay R2 and the eii'ect of this current will tend to move the armature of the `relay R2 to its spacing contact S. When the key K2 at the sending loop L2 is closed, batteries "B, and B3 Willbe in series With each other and their eH'ects will be additive, there,- by producing` a dominating magnetic Veifect in the Winding TVT Which will move the armature` of` the sending relay R2 to its marking contact M. The generator Gr` will then transmit current over the circuit L3. When the key K2 at the `loop L2` is opened, no current Will floiv through lthe Winding W7 and the magnetic effect of the Winding W3 Willdominate the armature of the sending relay and this armature Will close its spacing contact S. No currentivill then loivifrom thefgenerator `Gr over the circuit L3. 2

JTWhile this invention has been shown in certainparticular arrangements merely for the purpose oit' illustration, it Will be understood that the principles of this invention may be applied to other and `vvidely varied organizations Without departing from the spirit of the invention and the scope of the appended claims. i 2 3 y Vhat is claimed is:

1. In a telegraph system, the combination of a sending relay, a receiving relay, a loop connected to thewinding of the sending relay, a key being included in the loop, means responsive `to the opening of the `key to y lbring the armature-of said sending relay into a predetermined position, `means responsive to the operation of `said-sending relay to bring the armature of the receiving relay intol a: predetermined position and to maintain these armatures in said positions while the key remains open, anda sounder connected in series withthe armature and oneof the contacts of the. sending relay.

2. In a telegraph system, the combination of a sending relay, a. receiving. relay, aloop yconnected to the winding of the sending relay, akey being included insaid loop, means responsive to the opening of the key to bring the armature of the sending relay into a predetermined position, means to subsequently bring the armature of the receiving relay into a predetermined:position,and tovmaintain the armatures of the sending and receiving relays in these positions while the key remains open, and a sounder connectedin series with the armature and one of the contacts of the sending relay.

3. In a telegraph system. havingsending and receiving relays arranged for half-duplex operation, the'combination of means to produce a break signal, said means comprising means to bring the armatures of" the sending and receiving relays successively into predetermined positions andv to maintain these positions forv an appreciable period of time, and a sounder controlled by the armature of the sending relay.

4. In a half-duplex telegraph system, the combination of a receiving relay having a main winding through which pulses of direct current flow and two auxiliary windings having a common terminal, one of the terminals of one of the auxiliary windings being grounded, a. grounded-battery connected to the terminal common to said auxiliary windings, a sending relay having a grounded armature, the contact: of said sending relay being connected to the ungrounded tei-- minal ofthe other ofthe auxiliary windings, a sounder, and a secondV grounded battery connectedto the contact of the sending relay through said sounder.

5. In a carrier telegraph system having sending and receiving relays arranged for half-duplex operation, the-sending relay in`1 cluding an armature and two contacts, the combination of means to produce a( clean-cut break signal, said means comprising means to bring the armatures of the sending and receiving relays successively into predetermined positions and to maintain these armatures in these positions for an appreciable period ot' time, a sounder connected in series w-ith the armature and one of the contacts of the sending relay, and a source of alternating current connected in series with the armature and the other of the contacts of the sending relay.

April 1931-.

WIL'ION T. REA.

6. In a half-duplex telegraph system the

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