US2340065A - Telegraph system - Google Patents

Description

Jan. 25; 1944. W. LANG 2,340,065

TELEGRAPH SYSTEM 7 Filed March 24, 1943 2 Sheets-Sheet 1 /5 cwsss on au/wr sum z .9 4 5 STOP ----m/m-a CAM RIM 1 1}: guspficma CAM mom POSITIONS MARKING emu/r SPAC/NG bps/v Q MARKING. u: SPACIIVG INVENTOP MK'LASNG A WORNEV' Jan. 25, 1944.

W. Y. LANG TELEGRAPH SYSTEM I Filed March 24, 1943 2 Sheets-Sheet 2 INI/SNTOR WKLANG AT TORNEV Patented Jan. 25, 1944 TELEGRAPH SYSTEM Wilmarth Y. Lang, ".lowaco, N. J., assignor to BellTelephone L'aboratories, Incorporated, New York, N.Y.,.a-corporation of New York ApplicationjMarchjM, 1943,.Seria1 No. 480,319

8 Claims.

This invention relates to telegraphyapparatus and mechanisms and more particularlyto animproved telegraph receiving selector.

.Incertain telegraph switchingsystems and in other systems it is sometimes desirable to employ ax'blank signal, i. e., a code-combination in which all of the significant selecting impulses are spacing-to perform some switching or other function. When such signals are employed for switching-or other functions difficulty is sometimes encountered due to the fact that the usual single magnet selecting mechanism employed for. telegraph reception and control of switching and other functions are unable to distinguishbetween a.-so-

calledblank code combination-and a break signal or an open line conditionwhich ,isfrequently encountered .due to momentary disturbances -'to which telegraph transmission lines are frequently subjected.

Accordingly one of the objects of this inven-.

of at least two different signaling .-.conditions' which are transmitted over the-transmissionsystem. In start-stop or simplex telegraph systems additional synchronizing pulses 'are transmitted before and after each codegroup :of' pulses in order to maintain synchronismbetweenthe:

transmitting apparatus and the-receivingcapparatus connected to the system. pulse transmitted before the codepulses isusually'called the .start pulse and'is-so-rreferred'to hereinafter. The synchronizingpulse transmitted after the code pulses is usually called the .stop pulse. .Thezterm stop:pulse is vusedzin this specification to reierto thexpulse following the code pulses of each'codecombination independently of the character of the -pulse .in this position. A code combination thus includes the synchronizingpulses and the codepulses.

' Generally the lineis closed during .idleperiods during the time the transmission .circuitis established and this condition is frequentlycalled a marking condition. An open pulse, usually called a spacing pulse, is transmittedbefore each groupof codepulses as a start pulse. .-A-fter.each code combination amarking stop pulse istransmitted and then a spacing start pulse is trans- The synchronizing mitted before the next group of code pulsesetc.

Whena blank code combination is transmitted over the line a spacing start impulse followed by five spacing selecting impulses are transmitted over the line and this in turn is followed by a marking stop impulse.

When the line is interrupted due to hits or other circuit disturbances the stop pulse will also be spacing.

In accordance with the present invention blank codecombinations are distinguished from open lines or hits depending upon whether or not a stop pulse is marking or spacing. If the stop pulseis marking the equipment will respond to the code combination as a blank code combina-. tion whereas if the stop pulse is spacing the equipment will not respond to the open line or hit as a blank code. In other Words, the switch ing circuits or special functions will not be performed when an open line condition develops or a hit .or break signal is received over the line but will be performed when a blank code combinationis received.

The foregoing and other objects and features of this invention, the novelty of which is set forth in the claims appended hereto, may be more readily understood from the following specification when read with reference to the attached drawings in which:

Fig. 1 shows in schematic form the equipment and circuits in accordance with this invention for preventing the actuation of circuits can-' in accordance with the present invention together with graphs of both a blank signal and an open line condition or break signal;

Fig. 3 shows a perspective View of one embodiment of the invention applied to a common type of telegraph selector; and

.Fig. 4;shows typical telegraph receiving and selecting mechanisms to which the invention may be applied.

Referring now to the drawings, Fig. 1 shows the circuit arrangements and apparatus in S8118." matic .form in accordance with one embodiment of the present invention, 1 i represents the transmitting contacts of a transmitting instrument while I2 represents some break contacts which may be employed to transmit break signals over line H]. The break contacts l2 and the transmitting contacts II are connected by means of line ill to a telegraph receiving instrument.

Line It] may extend between different stations Line I may also include any suitable type of repeating and terminal equipment normally employed in the respective types of telegraph transmission. Line Iii may include switching apparatus and also extend through one or more switching centers or central station or exchanges.

It is also within the scope of the present invention to have the transmitting contacts II at the same station or closely adjacent the receiving instrument provided with the improved selecting arrangement in accordance with the present invention. As shown in Fig. 1, line Ill extends through windings of relays I3and I5. Of course, line III could extend to a terminal relay and then acircuit from the terminal relay or repeater ex tend through the line winding of relays I3 and I5. Relay I3 is the usual line relay and controls a selecting magnet I4 of the receiving telegraph instrument which may be of the type sometimes called a teletypewriter and in the case of shorter lines or when repeaters are employed the windings selector magnet I4 of the receiving instrument may be connected directly in series with line Ill instead of having the signals repeated from line If! to the selector magnet I4 by means of relay I3. Relay I5 has also been provided for actuating control magnet I9 as will be described herein.

As will be apparent to those skilled in the art in case sufiicient current flows over line ID, or in the local circuit from repeater of line I0, the winding of magnet I9 may be connected directly in, series to this line in the same manner as the selector magnet I 4 may be connected in series with the line. It will also be apparent to those skilled in the art that magnet I9 and selector magnet l4 may be controlled from the same receiving or repeating relay by connecting these magnets in parallel to the marking contact of the repeating relay. However. in order to reduce the contact load and wear each of the magnets is provided with a separate relay in the embodiment of the invention shown in Fig, 1.

The selector mechanism controlledvby the selector magnet I4 may be of'any suitable type such as those disclosed in U. S. Patents 1,745,633 granted to S. Morton et al. on February 4, 1930, and 1,904,164 also granted to S. Morton et al. on April 18, 1933, 2,255,794 granted to Lake, September 16, 1941, and 1,937.376 granted to Zenner on November 28, 1933.

Such selector mechanisms comprise a selecting cam barrel 35 as shown in Fig. 3 provided with a cam for each of the significant selecting impulses and the various levers cooperating with it which cause the receiving mechanism to selectively print or record characters in accordance with the received telegraph signals. The manner of operation of this equipment is described in detail in the above-identified patents. which patents are hereby made part of this application as if fully included herein. Inasmuch these mechanisms work in their, normal manner a detailed description of their operation would serve no useful purpose if repeated herein but would serve only to obscure the present invention.

In accordance with the present invention an additional cam I6 is mounted upon the same cam barrel 35 as the selecting cams and is caused to rotate with the selecting cams. The additional cam I6 in the embodiment shown in the present invention is a ring type of cam and cooperates with the projection ll of lever I8 in such a manner that the lever I1 is maintained in either one .of the two positions depending upon its setting at a particular instant in the cycle of operation of the cam barrel 35. As is well understood by those skilled in the art, cam barrel 35 is rotated through a friction clutch 30 under control of release levers and mechanisms actuated by the selector magnet I4 as shown in Figs. 1, 3 and 4. Upon the reception of a spacing start impulse, magnet I4 releases and in turn releases cam barrel 35 for rotation through one revolution. During this revolution the selecting mechanism of the receiving instrument is conditioned to selectively controlthe recording of the character or function represented by the received telegraph signals. Near the end of this revolution of cam drum 35,

the printing, perforating, or other function or' apparatus of the receiving device will set into operation and cause it to record or further respond to the received signal.

As indicated in Fig. 2 a blank signal comprises a spacing start pulse 5 and spacing significant impulses followed by a stop pulse. This signal is represented by the heavy line 21 shown in Fig. 2. An open line due to trouble conditions or the break signal transmitted over line I0 comprises a spacing start signahspacing selecting impulses, and also a spacing stop signal. In order to differentiate between the blank signal and an open line or a break signal it is necessary to determine whether or not a stop pulse is marking or spacing.

Added cam I6 together with lever l8 and the controlling magnet I9 have been provided to determine whether or not the stop pulse is marking or spacing. The contour of cam I6 and its orientation with respect to the significant pulses of a telegraph signal is illustrated in diagrammatic-form by line I6 of Fig. 2. The projection ll of lever I8fwhich cooperates with the cam is also indicated in Fig. 2.

By reference to the development of cam I6 shown in Fig. 2 together with the location of projection I'I it is evident that during the stop pulse the projection I! of lever I8 is released and permitted to assume either one or the other of two positions dependin upon whether or not magnet I9 is energized or deenergized during this time.

As shown in Figs. 1, 2 and 3 the projection IT is located approximately at the center of the stop interval assuming that the cam I6 in Figs. 1 and 3 is shown in its rest position. It is to be understood that this particular showing of th relative positions of projector I1 and the opening cam I6 is forthe purpose of illustration only. As will be readily understood by those skilled in the art the usual arrangement is to release the selectable or controlled element for only a short interval of time during a predetermined portion of the pulse interval in order to secure the best results. Also the length of the opening in cam I5 should be appreciably less than the entire pulse interval. Furthermore, it will be desirable to accurately time the interval during which the test of the stop pulseis made. In order to select this interval the'control magnet I9 and the pivot 3I supporting lever I8 are mounted upon a movable plate 20, the position of which relative to the cam barrel 35 may be changed by loosening screws 22 and sliding plate 20 around the cam barrel so'screws 22 slide in slot 34. 1

'Thu's by properly-adjustin the position "of plate 2fl'the particular portio'n of the stop pulse desired to control the positioning of lever |8 may lie-selected. 'Normally le ver 8'will not 'be released in thestop position of thecam'drum35. Instead therim portion-of'the cam It will have passed the projection I! and the lever -|8- when the cam drum 35'cornes torest. 'Inthis 'manner'theoperation-oflcvr Bis in no way eiiecte'd by'the time interval *betweensuccessive characters or pulses.

-Of"course,-as will-be readil -apparent to those skilled-in the art, if it is so-d'esiredthe orientation, that is, the position of'p1ate20 maybe so-regulatedtogether with the openingin-cam l6 that projection may be free to'mo'vewhen' thecam drum-35 is atres't.

Contacts 23 are operated in response to the reception of any signal in which all of the five significant pulses are spacing. The manner'in which these contacts are operated is well understood by those skilled in the art and is described in greater detail in United States Patents 2,120,235 and 2,112,234 granted to Beattie et al. on June 14, 1938, and March 23, 1938, respectively, the disclosures of which patents are hereby made a part of this application as if fully included herein. The blank pull bar of the specific type of telegraph mechanism shown in Fig. 4 is selected in response to a blank signal and the selection of this pawl bar through its upper extension causes contacts 23 to be momentarily closed, as is well understood by those skilled in the art.

However, the closure of contacts 23 does not take place during the reception of the blank code combination but during the succeeding revolution of the cam drum 35. This time relation is well understood, is due to the construction of the mechanisms, and is brought about by the fact that the actual printing or recording of each code combination cannot start until the entire code combination has been received. Thus the recording of one code combination takes place during the reception of the succeeding code combination. Similarly contacts 23 are closed in response to. the reception of one code combination during the reception of the succeeding code combination since these contacts close concurrently with the printing or with the recording of a character or during the performance of the function represented by the code combination.

Assuming first that a blank code combination is received, reception of this code combination will cause all of the five selecting elements to be positioned to their spacing position and cause the selection of the blank pull bar which in turn causes contacts 23 to be momentarily operated shortly after the completion of the reception of the blank code combination.

Since the blank code combination was transmitted a marking stop pulse will immediately follow the fifth spacing impulse. Magnet I9 will, therefore, be operated during the time the projection I! of lever I8 is free from the rim of cam l6. Consequently projection will be held outside of the rim of cam l6. With projection I! held outside of the rim of cam l6, contacts 2| will remain closed so that when the contacts 23 later close a circuit is completed for the operation of relay 25 from battery through the winding of relay 25 and closed contacts 23 and 2| to ground. As shown in Fig. 1, relay 25 completes a circuit for maintaining itself operated under control of key 24 and completes a circuit for lighting a signal lamp 26.

the art thatthe-simultaneous closurexof contacts 23-and 2| inresponse' 'to thereception of a'blank signal may'cause'the operation of other relays When'it is desired torelease relay 25 key' 24- will 'be operated -momentarily which interrupts the locking circuit of relay 25 and permits this relay to release.

If, however, a break signal, an open line or a hit, which is longer than-the complete codecombinationpis received overthe line the five selecting pulses will again cause the selection of the blank pull bar and the later actuation 'of contacts 23. In this case, however, a spacing pulse will be received immediately following the No. 5 selecting pulse. Consequently magnet l9 will be released or deenergized when the projection H of lever I8 is freed by cam l6. Spring 32 will then cause projection I! to move inside the rim of cam 6 where it will be held during the succeeding revolution of the cam drum 35. As shown in the drawing, with the projection I! held inside the rim of cam Hi the outer end 33 at lever 8 will cause contacts 2| to open. Consequently when the blank contacts 23 close shortly after the completion of the first revolution of the cam drum 35 the circuit of relay 25 will not be completed because contacts 2| are held open all during the entire succeeding revolution of cam drum 35 and thus of cam l6. In this manner the circuit of relay 25 is completed only when a blank code combination is transmitted but is not completed when a break signal or momentary circuit interruption causes break signals to be received by the receiving selector.

It also will be apparent to those skilled in the art that this invention is not limited to distinguishing between code combinations having marking and spacing stop pulses but may be employed to distinguish between code combinations having either marking or spacing pulses in any one of the other positions of the combination.

What is claimed is:

1. In a permutation code selector, apparatus responsive to the reception of a permutation code having all the significant code impulses thereof spacing for closing a contact and other apparatus responsive to a following spacing control impulse for opening the circuit through said contact.

2. In a permutation code selector, apparatus responsive to the reception of a permutation code having all the significant code pulses thereof spacing for closing a contact and other apparatus responsive to a following spacing pulse for preventing the completion of any circuit through said contact.

3. In a permutation code selector, apparatus responsive to a predetermined code combination for performing a switching operation, and selective equipment responsive to the succeeding pulse for controlling the performance of said switching operation.

4. In a start-stop permutation selector, apparatus responsive to the, reception of a predetermined code for selecting electrical circuits, and control circuits responsive to the following stop pulse for controlling the selected circuit.

5. In a start-stop permutation selector, a rotative element, equipment for releasing said element for rotation through one revolution in re- It will beat-onceapparent; to those skilled in sponse to a start pulse, mechanically operative selective apparatus responsive to the following code pulses for selecting electrical apparatus, and other mechanically selective apparatus responsiveto the stop pulse for controlin-g the selected apparatus.

6. A telegraph start-stop permutation code selector comprising a rotatable element, apparatus responsive to a start pulse to cause the rotation of said element through one revolution, a two position stop pulse member, a stop pulse cam rotated by said rotatable element and cooperating with said stop pulse member, and apparatus to position said member in either of its positions under control of a stop pulse.

a 7. In a telegraph start-stop selector a two position member, a rotatable cam for holding said member in either of its two positions during the major portion of the revolution, and apparatus responsive to a stop pulse to position said mem-- her in one of its positions.

8. In a start-stoptelegraph permutation code element under control of the stop pulse, and

equipment for operating the selected operatable member under control of said two position element.

WILMAR'I'H Y. LANG.

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