US2244597A - Telegraph system - Google Patents

Description

J`une'3, l941 I R. J. ANsPAcH TELEGRAPH SYSTEM 2 Sheets-Sheet 1 Filed Feb. 7. 1940 June 3, 1941. A R, 1 ANSPACH 2,244,597

TELEGRAPH SYSTEM Filed Feb. '7, 1940 2 Sheets-Sheet 2 Patented June 3, 1941 UNi'iEB T TELEGRAPH SYSTEM Application February 7, 1940, Serial No. 317,759

l Claims.

This invention relates to printing telegraph systems and, more particularly, to calling-in circuits for use with such systems.

In printing telegraph systems, particularly exchange systems, there is a possibility that a message transmitted from one station in the system might not be correctly recorded by the station intended to receive the message because of the failure, incorrect adjustment, or improper functioning of apparatus at the receiving station, The trouble at the receiving station might be of such nature that it would not cause any indicationto be registered at the sending station to inform the sending operator that the message is not being correctly recorded. The trouble might also be of such nature that it would prevent the receiving subscriber at an outlying station from transmitting a message to inform either the sending operator or a central office operator of the existence or this trouble and that a maintenance man should be sent to correct it.

Accordingly, it is an object of this invention to provide a printing telegraph system with a clalling-in circuit for enabling a subscriber at an outlying station to cause a signal device at another station or at a central ofce to be operated as an indication that something is wrong with the subscribers printing telegraph apparatus and that a maintenance man should be sent to correct it.

Another object of the invention is to provide a Y printing telegraph system having a plurality of outlying stations with means for ena-bling an operator at one station to communicate with an operator at another station by transmitting permutation code signals composed of impulses of positive current and ground and for enabling an operator at a third station to communicate with an operator at a fourth station by transmitting signals composed of impulses of negative current and ground.

Still another object of the invention is to provide a printing telegraph system having a plurality of stations with means for enabling an operator at a rst station to communicate with an operator at a second station by transmitting permutation code signals composed of impulses of positive current and ground and also for enabling the operator at the rst station to communicate with an operator at a third station by transmitting signals composed of impulses of negative current and ground.

These land other lobjects of the invention are accomplished by modifying printing telegraph systems to include the calling-n circuit. The description of the invention is directed to the use of the invention with systems shown and described in Patent 2,131,870, granted October 4, 1938, to W. W. Cramer. The disclosure of this Cramer patent is incorporated herein by reference as a part of this specication. However, the invention is not limited to the modied Cramer systems shown in the drawings as these are the preferred embodiments of the invention land are shown and described in order to illustrate and explain the features and principles of operation of the invention. Other modifications may be made without exceeding the scope of the invention.

The invention will now be described in detail with reference to the drawings in which:

Figure l represents a printing telegraph system somewhat similar to that shown in Fig. 1 of the Cramer patent but which includes an alarm device and a calling-in circuit;

Fg. 2 illustrates a system corresponding somewhat to the system shownin Fig. 2 of the Cramer patent but including an alarm device and a calling-in circuit;

Fig. 3 shows a system having four outlying stations connected to la main station for communication by various kinds of permutation code signais, such as signalscomposed of impulses of positive current and ground and signals composed of impulses of negative current and ground; and

Fig. 4 illustrates a subscribers station having two sets of transmitting apparatus for use with a portion oi the system shown in Fig. 3.

Fig. 1 shows a printing telegraph system which is somewhat similar to the system shown in Fig. l of the Cramer patent but which has been modied in accordance with the invention to include an alarm, or signaling, device I, a calling-in key 2, a positive battery 3, and a polarized relay 35. It has also been modified to include a subscribers station or line repeater 5, another polarized relay t, and batteries 8 and 9. The normal operation of the system is somewhat similar to that described in the Cramer patent. For west-to-east transmission, signals are sent over line L from the point 5 which may be either a subscribers station or a line repeater. If point 5 is a subscribers station, then the subscriber would initiate the transmission of signals; but, if it is aline repeater, then it would repeat signals originating at another station connected by a communication channel to the device 5.

In any event, the device 5 causes signicant current Variations to be made in the positive current from grounded battery 9. These current variations travel over line L from battery 9 and the device 5 to station A where they pass through The armature of relay l2 thus applies either negative battery I3 or positive battery Iii to a path leading through the induction coil and the' variable resistance 2d to the point 23. Here the current divides, one lportion going through the resistance 29, middle windings of polarizedV v relays i8 and 35, and then through the balancing network El to ground Et. The other'portion of the current travels through the resistance 23, top windings of relays I8 and 35, and out over ,line I li to the distant station B. The top and middle windings of relays Ill and are wound differentially so that the eiect on their armatures of the current from battery I3 or battery I d in their top windings is opposed and neutralized by the eiiect of this current in their middle windings. Since the top and middle winidings of relays i8 and 35 are oppositely wound, the armatures of these relays will not be operated by signaling current from batteries I3 and I. However, these same windings are in a series aiding connection for currents orginating from any battery applied at station B to the line it. The. poling is such that the effect of negative battery applied at Station B to line i9 is spacing on relays I8 and 35 while positive battery has a marking effect. The application of ground I l at station B to line it has a marking effect on both relays I8 and 35 but this is not sufficient to operate the armature of relay 35 due to the spacing bias on this relay.

A biasing circuit is provided extending from grounded battery (i2, through the variable resistance 22, through the bottom winding of relay i8 in one direction, through the bottom winding of relay 35 in the reverse direction, and then to ground.. This biasing circuit holds the armature of the receiving relay it on its marking contact and the armature of relay 35 on its spacing contact during west-to-east transmission.

At station B, the current passes over the calling-in key 2, through the induction coil 2li, resistance 2l, through the winding of the receiving relay l5, and then'through the sending contacts l I to ground I I. Also at station B are two negative batteries I6 and 32, the resistances Il, 3l, andl 33, a condenser 33', and a printer magnet 3S, all of which perform the same functions as in the circuit shown in Fig. l of the Cramer patent. Since the functions of this apparatus are the same as described in the Cramer patent, it is not necessary to repeat the description here because the disclosure of the Cramer patent has been incorporated hereinV by reference. It is suilicient to state that marking impulses are transmitted from the outlying station B to the main station A by applying ground I I to the line I i! and-that spacing impulses are transmitted from negative spacing battery it and negative battery 32 by removing ground l I from line I l? to render effective the combined negative current from batteries i6 and 32.

, When ground i I is connected to the sending contacts il, which` is the normal marking condition, the armature of relay I8 remains on its marking contact and the armature of relay 35 stays on its spacing contact as shown in Fig. 1. When ground I' is removed from contacts II, the combined negative potentials oi batteries I6 and 32 are applied to line Iii to produce a spacing eiect on relays Iii and 35. The armature of relay I3 moves at this time to its spacing contact to apply positive current from battery over the armature of relay it, through the upper windings oi relays and I2, and out over line L to the device 5. As the armature of relay 35 is already on its spacing contact, it is held there 'more securely now by both the biasing current in the bottomiwinding of relay 35, which is Wound in a direction which is the reverse of that of' relay I3, and also by the incoming current from batteries It and 32. Consequently, transmission of ordinary message signals over line H3 in either direction will not cause the operation of the armature of relay 35.

In the event that the equipment at the outlying station B becomes out of order and the subscriber at that station wishes to notify the operator at the main station A as described above, the subscriber at station B momentarily operates the calling-in key 2 to its lower contact, thereby removing ground Il from the line it and substituting positive current from battery 3. It is to be noted that the polarity of battery 3 is the opposite of that of the spacing battery IG. As was stated above, the application of positive battery at station B to line Il) produces a marking effect on relays I 8 and 35. As the armature of relay i8 is normally already on its marking contact, it is now held there more securely by both the biasing current from battery 62 and the incoming current from battery 3. This application of positive battery 3 to line ill also causes ther armature of relay 35 to move to its marking contact.

When the armature of relay 35 moves to its marking contact, it closes a path for current to pass from grounded battery 49 through the winding of the control relay 3 and over the armature of relay 35 to ground 66. Relay 63 now operates its armatures, the right armature closing a locking-up circuit for relay 63 from battery t9 and over the non-locking restoring key 55 to ground I5?. A t the same time, the left armature of relay t3 closes a path for current to pass from battery i9 through the alarm device I to ground 58, thereby operating the alarm device I which may be any suitable audible or visible indicating device, such as a lamp, bell, or buzzer. The operation of the alarm device I serves to indicate to Y the operator at station A that something is wrong with the apparatus at station B and that a maintenance man should be sent to correct it.

The alarm, or indicating, device I remains operated until the attendant at station A momentarily operates the non-locking restoring key 5I) to open the locking-upcircuit of relay 63. This causes relay 53 to release its armatures, thereby opening the energizing circuit of the alarm device` I which, consequently, discontinues. its operation.

As was stated above, Fig. 2 illustrates a system which is somewhat similar to the system shown in Fig. 2 of the Cramer patent but which includes the modifications described above in connection with Fig. 1 except that, due to the use of positive spacing battery 293 at the subscribers station B', battery 2%3', is negative. The use of positive spacing battery 293 at station B in Fig. 2 instead of the negative spacing battery 2 I 6 used in the system shown in Fig. 1 requires that the top and middle windings of relays 218, 234, and 235 be reversed with respect to the poling used in the system shown in Fig. 1. Accordingly, in the system shown in Fig. 2, the effect of positive battery applied to line 218 at station B' is spacing on relays 218, 234, and 235 while the effect of negative battery applied at station B' to line 2113 is marking on relays 218, 234, and 235. The application of ground 211 at station B' to line 218 has a marking eiect on. relays 218, 234, and 235 but this is not suiicient to operate the armature of relay 235 due to the spacing bias on this relay. Messages are transmitted over the system shown in Fig. 2 in a manner similar to that described in the Cramer patent but including the additional transmitting point 2115 which may be either a subscribers station or aline repeater and which operates in a manner similar to that described above in connection with Fig. 1.

Operation of the calling-in key 282 in Fig. 2 applies negative current from battery 283' to the line 218, thereby causing relay 235 to move its armature to its marking contact. As the armatures of relays 218 and 234 are normally already on their marking contacts, they are now held there more securely by both the incoming negative current from battery 283 and the biasing current from battery 282. The movement of the armature of relay 235 to its marking contact closes a path for operating the control relay 263 which operates its armatures and locks up in the manner described above. Operation of the left armature of relay 283 causes the operation of the alarm, or signaling, device 231 which remains operated until the attendant at station A' momentarily operates the non-locldng restoring key 258 to unlock relay 263.

Thus, in either system, by adding to the outlying subscribers station B, a battery which is of opposite polarity to the spacing battery at that station, a calling-in signal can be effected at the main station A without causing the operation of the armature of the receiving relay at the main station. This is of particular advantage because it permits the outlying station B to signal the main station A without interrupting any communication between station A and other stations in the system, such as the station 5 or any other station connected to the device 5.

For purposes of illustration, the invention has been described with reference to its application for effecting a calling-in signal in the systems shown in Figs. 1 and 2 of the Cramer patent. It is to be understood that the invention is not limited to use only with these systems but can be applied to other systems. Furthermore, the invention is not limited to effecting a calling-in signal but may be used for performing other functions, such as for enabling an operator at one station to communicate with a subscriber connected to relay 18 by applying negative battery and ground to the line 18 and for enabling an operator at an additional station to communicate with a subscriber connected to relay 35 by applying positive battery and ground to the line 18. Such a system is sho-wn in Fig. 3 which is a modification of the system shown in Fig. 2.

In Fig. 3, the main station, or centralotce, A1, has two subscriber, or line repeater, stations 335 and 3115' connected thereto by lines L1 and L2. The main transmission line 310 extending from station A1 has two subscribers stations B1 and B2 connected therein in series, each being somewhat similar to the station B' in Fig. 2. Station A1 is somewhat similar to the station A in Fig. 2 but is provided with an additional set of relays 312 and 385 and batteries 313', 314', 301', and 388' for use with the additional station 385.

Permutation code signals transmitted over line L1 from station 385 cause the armature of relay 312 to iuctuate between its contacts to apply either positive current from battery 314 or negative current from battery 313' to the line windings and balancing windings of the diierential relays 318 and 335. This procedure is somewhat similarto that described above for Fig. 1. These signals pass over the line 3111 to station B1. Here the signals pass over the armature of relay 348, through relay 315, over the armature of relay 338, and then along conductor 388 to junction 381. Here the signals pass over line 310 tostation B2 where they travel over the armature of relay 348', through relay 315', and then over the armature of relay 338 to ground 382'. This causes the armatures of relays 315 and 315' to uctuate between their contacts for controlling the printer magnets 338 and 333' which, in turn, cause the signals to be recorded at both stations B and B'.

Similarly, permutation code signals transmitted over line L2 from station 385 cause the armature of relay 312 to fluctuate between its contacts to apply either positive current from battery 314 or negative current from battery 313 to relays 318 and 335. These signals travel over lines 318 and 318' and are recorded at both stations B1 and B2 in a manner similar to that in which signals from station 335 are recorded at stations B1 and Bz.

The subscriber at station B1 can cause messages to be recorded at station 335 by operating the sending contacts 311 to cause the armature of relay 338 to fluctuate between its contacts to apply either negative current from battery 316 or ground 382 (located at station B2) to line 318. The negative current comes from battery 318 over the armature of relay 338, through relay 315, and

then over the armature of relay 348 to line 318. The path from ground 382 at station B2 extends yover the armature of relay 338', through relay 315', over the armature of relay 348', out over line 318 to junction 381 at station B1, conductor 388, and then over the path just traced from the armature of relay 338 to line 318. Due to relays 318 and 335 being diiierentially wound, as described above in regard to Fig. 2, relay 335 will respond tothese signals but relay 318 will not. This is similar to the operation of relays 218 and 235 in Fig. 2.

The signals from station B1 thus cause the armature of relay 335 to fluctuate between its contacts to apply either negative current from battery 395' or positive current from battery 38'1' to conductor 383' leading to junction 384'. Here the currents from batteries 395 and 331' pass through relays 386 and 312' out over line L2 to station 335' where they operate receiving apparatus to record the permutation code signals originating at station B1.

The subscriber at station B2 can cause messages to be recorded at station 385 by operating his sending contacts 311 to cause the armature of relay 338 to fluctuate between its contacts to apply either positive current from battery 383' or ground 332 to the armature of relay 338. The transmission path extends from the armature of relay 338', through relay 315', over the armature of relay 348', out over line 318' to junction 381 at station B1, conductor 388, over the armature ofV relay 338, through relay 3i5, over the armature of relay 3118, and then out over line 3M to station A1. Due to Vrelays 3 i8' and 335 being differentially wound, relay 335 will not respond to these signals but relay 3 i8 will move its armature back and-forth between its contacts in response to the signals originating at station B2 in vthe same manner that relay ZES actuated its armature in response to signals from station B' in the. system shown in Fig.V 2 described above. Relay Sie will thus apply either negative current from battery (95` or positive current from battery 357i to conductor 333 leading to junction 384. Frornthis point, the signals pass through relays-396 and SI2 and out over line L1 to station 305 where they operate receiving apparatus to record the permutation code signals originating at station B2.

' Any suitable timing or circuit controlling means known to those skilled in the art may be employed to control the system so that simultaneous transmission of signals from more than one of the four stations` 395, 3il5, B1, and B2 will be prevented. Such circuit controlling means are not absolutely essential to the system shown in Fig. 3 as variousI other arrangements can be employed for governing transmission. For example, the first quarter of an hour could be assigned for transmission by the subscriber at station 3%, the second quarter of the'hour could be assigned for transmission by the subscriber at station 3125', the third quarter could be assigned to the subscriber at station B1, and the fourth quarter to the subscriber at station B2.

1f desired, only one subscribers station may be connected tc the line Si@ instead of the two stations B1 and B2 shown in Fig. 3. A single subscribers stati-on B4 connected to line 3H! for communication with both stations 305 and 3il5' is illustrated in Fig. 4. Station B4 is somewhat similarA to the station B' shown in Fig. 2, except that station B4 is provided with two sets of sending contacts @ii and di l', has a negative battery M6 in addition to the positive battery 93, and hasV both a relay 433 and a relay 433 with their associated apparatus. The line 3W extending from station B4 is to be considered as equivalent to line 3H) extending from station A1 in Fig. 3. It is to be understood that the line 3i@ in Fig. 4 leadsY from station B4 to a main station, or central oice A1', similar to that shown in Fig. 3, and that this station A1 has two other stations M35 and 365', similar to those shown in Fig, 3 connected thereto for communication with station B4.

Permutation code signals originating at either station 355 or 3&5' are transmitted to station A1 and travel over line Slt to station B4 where they pass over the armature of relay 443, through relay M5, and then over the armatures of relays 438' and 438 to ground @52. These signals cause the armature of relay @i to uctuate between its contacts to control the printer magnet 43B which causes the signals to be recorded by the teletypewriter at station B4. Y

The subscriber at Station B4 can communicate with the subscriber at station 365 by operating the sending contacts t!! which cause the armature of relay E35 to iiuctuate between its contacts to apply either negative current from battery 446 or ground 582 to a path extending along conductor 33, over the armature of relay 38', through relay M5, over the armature of relay 448, and then out over the line 3H) to station A1. At station A1, the signals originated by the operation of the sending contacts 4H at station B4 Cil cause the armature of relay 335 to'repeat the signals into the same circuit leading to station 30.5 that was described above in the description 0f the operation` of the system shown in Fig. 3. During this period, the status of relay 3H! will be non-responsive to the signals from contacts fil l.

The subscriber at station B4 can likewise communicate with the subscriber at station 335 by operating the sending contacts i l' to cause the armature of relay 438' to fluctuate between its contacts to apply either positive current from battery @d3 or ground 482 to the path just traced leading over line 3M to station A1. At station A1 the signals initiated by the sending contacts M l' at station B4 cause relay 3l8 to change its status toA operate its armature for repeating the signals into the same circuit leading to station 335 that was described above in the description of the operation of the system shown in Fig. 3.

As was stated above in connection with the description of the operation of the system shown in Fig. 3, a circuit controlling or timing device could be incorporated into the system employing the stationv B4 to prevent the transmission of messages by more than one subscriber at a time. To

Vavoid the expense of such a circuit controlling arrangement, separate transmitting periods could be assigned to each of the transmitting stations in the-system. For example, the first quarter of the hour could be assigned for transmission by the subscriber at station Bil, the second quarter in the hour could be assigned for transmission by the subscriber at station 3%', the third quarter of the hour could be allotted to the subscriber at station B4 for transmission to the subscriber at station 3&35, and the last quarter could be assigned ior transmission by the subscriber at station B4 to the subscriber at station 395'.

Since various changes and modifications embodying the principles and features of operation of the invention can be made without exceeding the scope of the invention, the invention is to be limited only by the claims appended hereto. In construing the appended claims it is to be understood that the term relay is suiiiciently broad to include Various types of electron discharge relay devices, such as either vacuum or gas-filled tubes, and that the term differential relayis sufficiently broad to include such devices associated with circuits and current sources as to have a differential effect.

What is claimed is:

' l'. A telegraph system comprising in combination a telegraph station having a rst and second diierential relays, each with a plurality of windings and an armature, a communication channel extending from the station for the transmission of signals, each of said relays having one of its windings connected in series with the communication channel, transmitting means for transmitting signals comprising permutation code combinations composed of both current impulses of a preassigned polarity and ground over the communication channel to the telegraph station, control means `for allowing only the rst of the differential relays to operate its armature to follow the permutation code signals received over the communication channel, means for transmitting current of a polarity opposite to the said preassigned polarity over said communication channel to the telegraph station, and means for causing the second differential relay to operate its armature in response to the transmission over the communication channel to the station of current of a polarity opposite to said preassigned polarity.

2. A telegraph system comprising in combination a telegraph station having a first and second electroresponsive devices, a communication channel extending from the station for the transmission of signals, transmitting means for transmitting signals comprising permutation code combinations composed of both current impulses of a preassigned polarity and ground over the communication channel to the telegraph station, control'means for causing only the first of said electroresponsive devices to follow said permutation code signals, means for transmitting current of a polarity opposite to said preassigned polarity over the communication channel to the telegraph station, and means for causing the second of said electroresponsive devices to change its status in response to the transmission over the communication channel to the telegraph station of current of a polarity opposite to said preassigned polarity.

3. A telegraph system comprising in combination a first telegraph station, a second telegraph station, a communication channel for connecting the two stations for the transmission of permutation code signals composed of marking and spacing impulses, means for transmitting a marking impulse from the second station to the first station in response to the application of ground at the second station to the communication channel, means for transmitting a spacing impulse from the second station to the first station in response to the application of current of a preassigned polarity at the second station to the communication channel, said first station having a receiving relay and a polarized relay connected into the communication channel, both said receiving relay and said polarized relay each having an armature, said first station also having an indicating device, an energizing circuit for operating said indicating device, a controlnelay for controlling the opening and closing of said energizing circuit, means for controlling the energizetion of said control relay Yin responseto a certain operation of the armature of said polarized relay, and means for directly operating only the armature of said polarized relay inl response to the application at the second station to the communication channel of current of opposite polarity to said preassigned polarity.

4. A telegraph system comprising in combination a rst telegraph station, a second telegraph station, a communication channel for connecting the two stations for the transmission of permutation code signals composed of marking and spacing impulses, means for transmitting a marking impulse from the second station to the rst station in response to the application of ground at the second station to the communication channel, means for transmitting a spacing impulse from the second station to the first station lin response to the application of current of a preassigned polarity at the second station to the communication channel, said rst station having a receiving relay and a polarized relay connected into the communication channel, both said receiving relay and said polarized relay each having an armature, said first station also having an indicating device, an energizing circuitfor operating said indicating device, a control relay for controlling the opening and closing of said energizing circuit, a normally open energizing circuit for said control relay, means for closing said normally open energizing circuit in response to a certain operation of the armature of the polarized relay,l a

locking-up circuit for maintaining the control relay energized after its energizing circuit has been closed by the operation of the armature of the polarized relay and for maintaining the indicating device operated, means for directly operating only the armature of said polarized relay in response to the application at the second station to the communication channel of current of opposite polarity to said preassigned polarity, and means for opening said locking-up circuit for effecting the deenergization of the control relay and for discontinuing the operation of the indicating device.

5. A telegraph system comprising in combination a first telegraph station having a signaling device, a second telegraph station, a communication channel for connecting the two stations for the transmission of permutation code signals composed of marking and spacing impulses, means for transmitting one kind of said impulses from the second station to the rst station in response to the application of ground at the second station to the communication channel, means for transmitting the other kind of said impulses from the second station to the rst station in response to the application of current of a preassigned polarity at the second station to the communication channel, and means for effecting the operation of said signaling device at the rst station in response to the application at the second station to the communication channel of current of opposite polarity to said preassigned polarity.

6. A telegraph system comprising in combina.- tion a first telegraph station having an electroresponsive device and an indicating device, a second telegraph station, a communication channel for connecting the two stations for .the transmission of permutation code signals composed of marking and spacing impulses, means for transmitting one kind of said impulses from the second station to the first station in response `to the application of ground at the second station to the communication channel, means for transmitting the other kind of said impulses from the second station to the rst station in response to the application of current of a preassigned polarity at the second station to the communi-` cation channel, means for effecting the operation of said electroresponsive device in response to the application at the second station ;to the communication channel of current of opposite polarity to said preassigned polarity, and means for effecting the operation of said indicating device in response .to the operation. of the electroresponsive device.

7. A telegraph system comprising in combination a first telegraph station, a second telegraph station, a communication channel for connecting the two stations for .the transmission of permutation code signals composed of marking and spacing impulses, means for transmitting one kind of said impulses from the second station to the first station in response to the application of ground at the second station to the communication channel, means for transmitting Itheother kind of said impulses from the second station to the first Vstation in response to the application of current of a prf-:assigned polarity at the second station'to the communication channel, said first station having a plurality of relays connected into the communication `channel, each of said relays having an armature, said first station also having an indicating device, means for eiecting the operation of the indicating device in response to a certain operationof the armature of a preassigned one of said plurality of relays, and means for directly operating onlythe armature of said preassigned relay in response to the application at the second station to the communication channel of current of opposite polarity to said preassigned polarity.

S. A telegraph system comprising in Ycomicination a` first telegraph station, a second telegraph station, a communication channel for connecting the two stations for the transmission of permutation code signals composed of negativean'd positive current impulses, said first station having a plurality of relays connected into the communication channel, each or said relays having an armature, said first :station also having an indicating device, an energizing circuit for operating said indicating device, a control relay for controlling the opening and closing oi said energizing circuit, means for controlling the energization of said control relay in response to a certain operation of the armature of a preassigned one'of said plurality of relays, and means for directly operating only the armature of said preassigned relay in Vresponse to the application of current of a certain polarity applied at the second station to the communication channel.

9. A telegraph system comprising in combination a first telegraph station, a second telegraph station, a communication channel ior connecting the tvro'stations for the transmission of permutation code signals composed of negative and positive current impulses, said first station having a plurality of relays connected into the communication channel, each of said relays having an armature, said rst station also having an indicating device, means for directly operating the armature of only a preassigned one of said plurality of relays in response to the application to the communication channel of current of a certain polarity at the second station, means for effecting the operation of said .indicating device in response to a certain operation of the armature .of said preassigned relay, and means for discontinuing the operation or" said indicating device.

li). A telegraph system comprising in combination a main telegraph station, a plurality of outlying telegraph stations, a plurality of communication channels for connecting the outlying stations to the main station, first transmitting means for transmitting one type of permutation code signals over one of the communication channels to the main station, second transmitting means for transmitting another type of permutation code signals over one of the communication channels to themain station, sending means at'the main station for sending received permutation code signals to other of the outlying stations, and control means for controlling the operation of said sending means without the assistance of routing signals for sending only one type of received permutation code signals to one of the other outlying stations land for sending only the other type or" received permutation code signals to another of the outlying stations.

, 11. A telegraph system comprising in comicination va main telegraph station having a plurality of relays, each of said relays having an armature, a plurality of outlying telegraph stations, a plurality of communication channels for connecting the outlying stations to the main sta- Y tion, means for enabling an operator at one of the outlying stations to transmit over one of the communication channels permutation code signals composed of impulses of positive current and ground to the main station'for operating the armature of one of said relays for repeating the signals to one of the other outlying stations, and means for enabling an operator at another outlying station to transmit permutation code signals composed of impulses of negative current and ground to the main station for operating the armature of another of said relays for repeating the signals to still another of the outlying stations.

12. A telegraph system comprising in combination a main telegraph station, a first and second outlying telegraph stations, a first communication channel for connecting the main station and the iirst and second outlying stations inseries, said main station having a first and second dierential relays, each of said differential relays having one winding connected in series with said first communication channel, each of said differential relays havingY an armature, a third outlying telegraph station, a second communication channel for connecting the third outlyingstation to the armature of the rst differential relay, a fourth outlying telegraph station, a third communication channel for connecting the fourth station to the armature of the second diirerential relay, rst transmitting means for transmitting permutation code signals from the first station over the rst communication channel to the main station and through windings of the differential relays, means at the main station for causing only the rst ofthe diferential relays to operate its armature to repeat said signals over the second communication channel to the third station, second transmitting means for transmitting permutation code signals from the second station over the rst communicationl channel to the main station and through Windings of the diierential relays, and means at the main station for causing only the second difierential relay to operate its armature to repeat said signals over the third communication channel to the fourth station.

13. A telegraph system comprising in combination a main telegraph station, a first outlying telegraph station, a communication channel for connecting the rst station to the main station for transmission of signals, a second and third outlying stations connected to the main station, signal transmitting means at the irst station for transmitting permutation code signals over the communication channel to the main station, control means at the main station for transmitting some of said signals to the second station to the exclusion of the third station and for transmitting other of said signals to the third station Ato the exclusion of the second station, and means when the system is in an idle condition for enabling messages to be transmitted from either the second or third stations through the main station and over the communication channel to v the iirst station.

14. A telegraph system comprising in combination a main telegraph station, a first outlying telegraph station, a communication channel for connecting the rst station to the main station for transmission. of signals, a second and third outlying telegraph stations connected yto the Vmain station, signal transmitting means at the first station for transmitting permutation codo signals over the communication channel to the main station, control means at the main station for transmitting some of said signals lto the second station to the exclusion of the third station and for transmitting other of said signals to the third station to the exclusion of the second station, means for causing the control means to transmit every one of the signals originating at the first station to the second and third stations selectively, said control means comprising two differential reiays each having one of its Windings connected directly in series with the cornmunication line leading to the rst station.

15. A telegraph system comprising in combination a main telegraph station, a first outlying telegraph station, a first transmission line for connecting the iirst station to the main station for transmission of telegraph signals, a second outlying telegraph station, a second transmission line for connecting the second station to the main station for transmission of telegraph signais, a third outlying telegraph station, a third transmission line for connecting the third station to the main station for the transmission of telegraph signals, first transmitting means at the first station for transmitting a iirst type of telegraph signals over the first transmission line to the main station, second transmitting means at the first station for transmitting a second type of telegraph signals over the first transmission line to the main station, iirst repeating means connected into said first transmission line at the main station for repeating only the first type of said signals over only the second transmission line to the second outlying station, and second repeating means connected into said rst transmission line at the main station for repeating only the second type of said signals over only the rst transmission line to the third outlying station.

RUSSELL J. ANSPACH.

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