US2260711A - Multistation communication system - Google Patents

Description

Oct. 28, 1941. F. G. HALLDEN MULTISTATION COMMUNICATION SYSTEM Filed Feb. 24, 1940 2 Sheets- Sheet l INVENTOR. fiEDEH/C/f 6. HALLDE/V fiw ATTORNE I IF I I I A I Um I I I L Oct. 28, 1941. F. G. HALLDEN MULTISTATION COMMUNICATION SYSTEM Filed Feb. 24, 1940 2 Sheets-Sheet 2 NGE A TTURNE Y.

Patented Oct. 28, 1941 MULTISTATION COMMUNICATION SYSTEM Frederick G. Hallden. Bellerose, N. Y., assignor to Postal Telegrap New York, N.

h-Cable Company (New York), p Y., a corporation of New York Application February 24, 194o, seria1 No. 3,20 ,554

9 Claims. (Cl. 178-2) This invention relates to printing telegraph circuits and more particularly to printing telegraph circuits utilizing a single line conductor to interconnect a multiplicity of printing telegraph instruments.

' In printingtelegraph systems it is often desired to have a plurality of way-stations'which may be selectively interconnected with a printer set at a main ofii'ce for communication. It is desirable that such systems be made as simple as possible and that a simplified selective arrangement be provided" atthe main office for selecting any desired one'of the way-stations for communication. It is also desirable that in such systems the operators'at any of the way-stations may be able to call the main station when they desire. Such systems. have been devised utilizing a separate wire other than the printer'signalling line for conducting the'call and selective operations. Howevenin the interest of simplicity it is desirable that the selection and calls may be made over the'same line that carries the usual communication. r

In accordance with my invention I provide a communication circuit such as a printing telegraph circuit of the general type described above, having a simplified selecting, calling and recording arrangement utilizing the common communicationlin'e.

- 'It is an object of ,myinventiorr to provide a selecting means under control of a main station for making operative the printingtelegraph apparatus at another station.

' Another object of my invention is to provide a simple, inexpensive selecting device and one a I which may be operated entirely by alternating current;

Another object of my invention is to maintain inoperative theprinting equipment at all stations except the one selected by the controlling p station.

A further object of my invention is to provide for recording calls from any of the stations at themain controlling station.

A' still further object of provide an arrangement for storing a code signal corresponding to a call signal when the circuit is in operative condition for communication, and to make this storage means operative to transmit the call signal immediately the communication circuit. k

According to amain feature ofmy invention the main or controlling station includes a message call circuit "register with an associated operating 'relay, a selector unit with its associated upon termination of relays and an answering jack and signal jack arrangement with an associated printer set. Each way-station includes a polar relay with a selector unit and associated alternating current relays, a code transmitter for transmitting calls to the centralstation with associated alternating my invention is to of plug J will complete battery through the winding of relay M, sleeve contacts of jack K, winding of relay L to ground.

the energizationof tery through contacts current relays and a standard printer; set.

* Further objects and features of my invention will 'becomeapparent from theparticular description'of my invention made in connection with the accompanying drawings, in which Figs. 1 and 1A taken together show a circuit diagram of an arrangement in accordance with my'invention, and

- Fig. '2 is a diagram indicating the line signals for selecting and calling. v

In Fig. 1-is shown a control; station l0, comprising a printer set N, a drop jack unit l2, and a main oflice selector connected over a line to a plurality: of way- stations 40, 60, and 80, Fig. 1A, the line-being grounded at 9!]. The wiring at station 40 only. has been illustrated, it being understood that stations and have substantially similarcircuits. I Y V In the normal idle conditionpositive battery extendsthrough winding of drop relay A, break and armature contactsot relay B, winding of relay C, breakand armature contacts of relay D toline 30. "At each station the line 30 extends through the-winding-of a polar relay E, armature andback contacts of relay F, break and armature contacts of 'relay G, and at the last station 80 to ground at 90. Polar relays E will operate whenever negative battery is appliedto the line from the control station l0.

p Method of selecting a station desired to select a particular H of a rotary selector switch Whenever it is station, the rotor 2| is turned to engage one of its contacts I to gage its contact 3, which contact corresponds to connected to main printthe jack K, The sleeve a circuit from negative way-station 40. Plug J er I l is then inserted into Relay L operates closing its contacts and causing the printer motor I3 over an obvious circuit and also connecting positive bat- M of theprinter tothe tip of' plug J which, since it is inserted in jack K, extends positive battery through the makediately and insure that the motor will rotate for one complete revolution of cams P and Q and the brush R. As soon as cam Q has rotated a short distance its contacts will close operating relay B over an obvious circuit, transferring the line from the break to the make contact ofthis relay, and negative battery will be applied to line 30 from negative source over contacts 3, 4 of relay M, and a make contact of relay B.

Relay B will be released immediately after cam Q is rotated past the small depression provided therein. This operation and release of relay B causes operation of polar relay E at each Way station. The short negative impulse produced by operation of relay B is represented by the start impulse 200 shown in Fig. 2. Relay E operates closing contacts I and 4, completing an obvious circuit to an alternating current source causing motor U to operate, rotating cams T and V with it. Contacts I and 2 on cam T will close almost immediately and insure that the motor U will run one complete revolution of cams T and V. The guard lamp X will also light at this time and serves as an indication that the line is busy. Contacts 3 and 4 of cam T also close causing operation of relay S.

As motor N at the selecting station continues to rotate the brush R will pass over commutator segments I to II, inclusive, in succession. As segment 3 is reached a circuit will be established from ground, brush R, segment 3, rotor H, winding of relay B to positive battery, operating relay B. Relay B will release as the brush R leaves segment 3. This sends out on line 30 another negative impulse, selecting impulse 20I, Fig. 2, which is shorter than the start impulse 200, this short impulse of negative current transmitted over line 30 reoperates relay E. As cam V has been rotating during this period, the indent 4| on its periphery will permit its contacts to close momentarily at this point in its revolution. At the selected station, in this instance station 40, this will occur at the time when the selecting impulses cause relay E to close its contacts. At the other stations the cams V are arranged so that their notches are in different positions so that the contacts will not be closed at any except the selected station. Alternating current relay G will operate from an A. C. source, winding of relay G, contacts of cam V, upper make contact of relay S, make contact of relay E to ground, and will lock up through its own make contacts and contacts 3, 4 to cam T. The other make contacts of relay G will extend power to the motor receptacle 43 over an obvious circuit for operation of the way-station printer motor, and the lower break contact of relay G opens,

removing the short circuit from the printer magnets 44 at the way-station.

Just before the end of the revolution of motor N at the selecting station, brush R will pass over segment II causing energization of relay D from ground, brush R, contact II, winding of relay D, upper make contact of relay M to posi tive battery. Relay D will operate and lock up through contacts I and 8. The line is transferred from contact 3 to contact 6 of relay D, the tip of jack K, plug J to the main oflice printer set. Contacts I and 2 of relay D, hold relay C in its operated position, contacts 9 and I 0 of relay D open. Almost immediately after this operation of relay D, contacts of cam P Will open thereby breaking the circuit for motor N causing it to stop. At this same time contacts I and 3 of relay E and the contacts of relay S have completed a locking circuit for relay S which will remain operated. The contacts of cam T will also open causing synchronous motor U to stop. Intercommunication may now be carried on between the main station I 0 and waystation 40. Cam V is adjustable on the shaft of motor U so that it may be positioned properly to close its contacts only when the selecting impulse corresponding to the station, is transmitted by the control station. As the cams V at the various stations are positioned to correspond to different station numbers only one can be selected at a time by the control station.

To terminate a connection, plug J is removed from jack K at the control station. As the plug is removed the inner spring contacts of jack K close. A moment later relays M and L deenergize. As relay M releases its contacts 6 and 1 open the circuit of relay D. Relay D is a slow release relay and will remain operated a short period after the circuit to its winding has been opened. During this interval a circuit is established from negative battery through contacts 4 and 5 of relay M, tip and inner spring of jack K, contacts 6 and 4 of relay D to line 36, sending a very short disconnect signal 202 of Fig. 2 to the line. Relay E is operated, opening contacts I and 3 of relay E and deenergizing relays S and G. Relay D then releases, restoring positive battery to the line at its upper break contacts and reestablishing the line circuit to its idle condition. This negative impulse 202 is shorter than the start or select impulses and does not maintain relay E operated long enough for motor U to start after relay S has released.

To call from a way-station Should a way-station desire to initiate a call, the operator thereat may operate the code transmitter provided at each station. The code transmitter is provided with a code wheel Z arranged to send several short impulses tothe line and. then a long impulse. The code wheel is adjustable on its motor shaft so that any predetermined number of short impulses may be transmitted to the line preceding the long impulse. For example, station 40 may cause the register to record 2- short impulses, 205, 206 and one long impulse 201, Fig. 2. Stations 60 and may have three short impulses followed by a long impulse and four short impulses followed by a long impulse, respectively. For the purposes of explanation, we will assume that way-station 40 is calling. The operator there presses the call key 45, assuming that at this time the line is in its idle condition. Alternating current relay F will operate from A. C. source to ground over key 45 opening its upper contacts and will lock up through its own contacts and contacts 5 and 6 of cam Y of the code transmitter. The closure of the lower outer make contacts of relay F completes an obvious circuit to an alternating current source causing synchronous motor 46 of the code transmitter to rotate. Cams Z and Y rotate with'the motor.

distinctly understood that this illustration wa's Contacts 3 and 4 of cam Y almost immediately close and insure rotation of the cams for one complete revolution. As the motor continues to rotate, contacts I and 2 of cam Z cause interruptions in the line circuit. These interruptions are a series of short'imp'ulses followed by a longer impulse caused by the projections on cam Z. Upon transmission over the line'these impulses will times and recorder 25 will record the call over a circuit extending from positive battery, contacts 5, 6 of relay M, contacts of relay C, winding of relay 22, to ground. The number of short signals preceded by the long signal determines which of the stations has called. The first interruption again operate and look through its o-wn'contacts and contacts 5, E of cam Y. Closure of theouter make contacts of relay F prepares a circuit from an alternating current source through the motor 46 of the code transmitter. However, the circuit cannot be completed at this time due tothe fact that the circuit is open at the lower make conacts of relay S. Relay S will be locked up at this time and the code transmitter cannot yet start. The moment the line circuit becomes idle by the removal of plug J at the main station, relay S will deenergize. This completes a circuit through the break contacts of relay S and contacts 3, l of relay E, causing synchronous motor and the code transmitter to rotate. The succeeding operations of recording the call are then the same as previously described.

If more than one way-station initiates a call when the line circuit is in the busy condition, relays F at each of these stations will lock up and prepare the circuits as previously described. As soon as the circuit becomes idle, the code transmitters at all such stations will become operative and will simultaneously transmit their code impulses to the line. Since mitters operate synchronously the record on the tape will indicate by the number and position of the long impulses, the number of each of the stations which is called. As an illustration, if stations 60 and 80 having their code signals when made operative would cause register 25 to record three short dashes followed by two long dashes indicating that both stations 4 and 5 had called. The operator then at the main selecting stat-ion could set rotor H to one of these stations answering. the call and when that call was terminated, set the rotor to the other station to complete a call there.

By use of this arrangement, it is seen that a simple operating printing telegraph system is provided, wherein calls from the way-stations may be initiated during periods when the line is busy and will be answered from the main station as soon as the busy condition of the line is terminated. Furthermore, a simple selective means utilizing merely the time adjusting of the cams is provided so that complicated code signal controls are entirely avoided.

While I have disclosed by way of single embodiment of my invention,

illustration a it should be cause relay C to operate a like number of' all of these code transthe codes previously set V forth had initiated a callduring a busy period stations, printing telegraph Til ' tively, means responsive and synchronous mademerely by way of example and not as alimitation of the scope thereof. Various'adaptations, modifications and applicationsof my invention may be made within the spirit and scope of this disclosure, as defined in the accompanying What is claimed is: 1

1. A communication system comprisinga main control station, adjustable way-station selective means at said control station, a plurality'of wayapparatus and selective call receivers at each of said way-stations, a communication line interconnecting said main station and "said way-stations, means at said main station for transmitting a start signalsaid main station and to said start signal for way-station selective call receivers respecto operation of said station selective means for transmitting over said line a selecting signal dependent upon the ad'- justment of said means, and means at the selected way-station controlled by said-selective signal and said selectivecall receiver 'for render ing the associated printing telegraph apparatus operative for communication over said line.

over said line, means at Way-stations responsive starting operation of said means and said selective v2. A communication system according to claim for transmitting said 1', wherein said means v start signal transmits a signal of longer duration than said select signal. 1 1

3. A communication telegraph system accord-Q ing' to claim 1, further comprising synchronous ly operating motor means for operating said way-station selective means and said selective call receivers, and means operative after one cycle of operation of said motors for stopping them.

4. A communication system comprising a main control station, printing telegraph apparatus thereat, adjustable way station selective means at-said control station, comprising an adjustable selecting switch, a rotary selective transmitter operatively associated with said selecting switch,

drive means for said transmitter, a plurality of way-stations, printing telegraph apparatus and selective call receivers at each of said way-stations, comprising synchronously operating drive means, and selective cam means driven by said synchronously operating drive means, a communication line interconnecting said main station and said way-stations, means at said main station and way-stations responsive to said start signal for starting operation of said synchronous drive means, means responsive to operation of said rotary selective transmitter for transmitting over said line a selecting signal dependent upon the adjustment of said switch, and means at the selected waystation controlled by said selective signal and said selective cam means for rendering the associated printing telegraph apparatus operative for communication over said line.

5. A communication system according to claim 1, further comprising means at each station for transmitting over said line call signals, means at said control station responsive to said call signals .for recording said calls, means at said way-stations for storingcalls in event said line is connected for communication, and means responsive to disconnection of said line after termination of communication for transmitting said stored signals over said line to said means forrecording said calls.

6. A communication system comprising a main claims:-

station, a plurality of way-stations, a transmission'line interconnecting said main station and said way-stations, means for selectively establishing communication between said main station and a selected one of said way-stations, call transmitting means at eachway-station for transmitting calls over said line to said main station, recording means at said main station for recording said calls, signal storage means at each way-station for storing call signals when said line is being used for communication, and means responsive to disconnection of said line from communication condition for successively transmitting said call signals over said line to said recorder.

7. A communication system comprising a control station, printing telegraph apparatus, a call recorder and an adjustable way-station selective means at said control station; a plurality of waystations; printing telegraph apparatus, a selective call receiver, and. a control station calling means at each of said way-stations; a communication line interconnecting said control station and said way-stations; means at said control station for transmitting over said line start signals to initiate operation of said selective call receivers at all of said way-stations; means for transmitting over said line a station selective signal dependent upon the adjustment of said way-station selective means; means at the waystation selected, responsive to said station selective signal, for rendering the printing telegraph apparatus at the selected station operative; said control station call means comprising call transmitting means'for transmitting a distinctive signal from each of said way-stations over said communication line to operate said call recorder at said control station; means for initiating operation of said call transmitting means; said last named means preparing a circuit for initiating said operation in event the line is in use for communication; and means responsive to termination of communication connections for operating said transmitter,

8. A communication system comprising a main station, a plurality of way-stations, a transmission line interconnecting said main station and said way-stations, call transmitting means at each way-station for transmitting call signals over said line to said main station, means at said main station for. recording said calls, signal storage means at each way-station for storing call signals and means responsive to a change in condition of said line for transmitting said call signals to said recorder.

9. A communication system according to claim 8, wherein said call transmitting means comprises means for transmitting a plurality of short impulses followed by a long impulse, the number of short impulses preceding the long impulse being different at each of said stations, whereby said signals Will be distinguishably recorded at said main station even when simultaneously transmitted.

FREDERICK G. HALLDEN.

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