US2459904A - Telegraph signal code translator - Google Patents

Description

Jan. 25, 1949.

Filed Deo. 9, 1943 M4N s/ Tren a'ls rfi/su E. F. WATSON TELEGRAPH SIGNAL GODE TRANSLATOR 3 Sheets-Sheet 1 /NVE/vro? E. F WATSON 5yd@ a. cue? ATTORNEY Jan. 25, 1949. E. F. WATSON 2,459,904

TELEGRAPH SIGNAL GODE TRANSLATOR Filed Dec. 9, 1943 I5 Sheets-Sheet 2 Jan. 25, 194.9. E F, WATSON v 2,459,904-

TELEGRAPH SIGNAL CODE TRANSLATOR Filed Dec. 9, 1945 3 Sheets-Sheet 5 /m/E/v Tof? -E .F WATSO/V Patented Jan. 25, 1949 TELEGRAPH SIGNAL CODE TRANSLATOR Edward F. Watson, Larchmont, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application December 9, 1943, Serial No. 513,501

This invention relates to improvements in telegraph transmission systems. More specically this invention relates to the translation of multielement permutation telegraph signals, in accordance with one code, into multielement permutation telegraph signals in accordance with a different code.

Where a first telegraph system arranged for the transmission of signals in accordance with a iirst code is connected to a second telegraph system arranged for the transmission of signals in accordance with a second and different code, it is necessary to translate the signal combinations in accordance with the first code into signal combinations in accordance with the second code before they can be transmitted over the second system. The invention herein performs such translation automatically, by electromechanical means. If the second system is reconnected to a third system employing the original code it is necessary to retranslate the signals into the original code. The invention herein performs such retranslation also automatically by electro-mechanical means.

In the invention herein a long non-loaded submarine cable system, designed for the transmission of the relatively slow three-condition permutation code telegraph signals or cable code signals, as they are known, and equipped at one end with a transmitter connected to a source of such signals and at the other end with a receiver arranged to receive such signals is used as a link between two relatively fast rive-element twocondition permutation telegraph code signal systems. Ordinarily the cable is connected to its cable code tape transmitter and its cable code receiver. When signals originating in the veelement system are to be transmitted, a switch associated with the live-element system is operated.Y This disconnects the cable transmitter from its normal source of signal supply and connects it to the iive-element system. Then a special multielement code signal which is generated automatically is impressed on the cable transmitter and transmitted to the distant end of the cable. In response to this the distant end of the cable is switched so that instead of being connected to its regular cable code receiver it is connected to a receiving retranslator. After the signal codel combination which performs the switching has been transmitted the five-element twocondition signals generated by the transmitting mechanism associated with the five-element system are changed in a transmitting translator into 13 Claims. (Cl. 178--26) four-element three-condition signals and impressed through a signal transmitter on the cable. At the distant end the four-element signals are directed to the receiving retranslator. Here the four-element signals are changed into the original live-element signals.

When transmission from the five-element system has ended, a second special multielement code signal which is generated automatically is transmitted to transfer the distant receiving end of the cable back to its regular code receiver.

The invention may be understood from the following description when read with reference to the associated drawings in which:

Fig. 1 shows the five-element system and the transmitting translator which translates the veelement signals into four-element signals;

Fig. 2 shows the cable code system including the tape transmitter, the relay transmitter, the cable, the cable code receiver, the transmitting switching mechanism which switches the cable relay transmitter from the cable code transmitter of Fig. 2 to the five-element system of Fig. 1 and the receiving switching mechanism which switches the receiving end of the cable between the cable code receiver of Fig. 2 and the four to five-element retranslating receiver of Fig. 3;

Fig. 3 shows the four to five-element retranslating receiver;

Fig. 4 is a table showing codes used in explaining the invention; and

Fig. 5 is a diagram showing the manner in which Figs. 1, 2 and 3 should be arranged to form an operative system.

Refer to Fig. 2. All of the apparatus indicated in this figure with the exception of the transmitting switching mechanism is well known in the cable telegraph art and it will not therefore be describedin detail, except insofar as it is necessary to an understanding of the code translating and retranslating arrangement of the invention herein.

The cable code tape transmitter 20| may be of the general automatic cable code type shown in Patent 1,517,110, T. F. Foley, November 25, 1924, modied as shown in Fig. 2 herein. The regenerative repeater 2 I9 in Fig. 2 may be of the type disclosed in Fig. 3 of Patent 1,827,460, F. G. Creed et al., October 13, 1931. The six pulse selectors 25|) and 210 in Fig. 2 may be of the type disclosed in Patent 1,868,703, R. G. Griffith, July 26, 1932. It is understood, however, that the circuits of the present invention are not limited to one with cooperating apparatus in accordance with the spe- Vtact 224, winding of relay 2G53 and resistance 2 fic embodiments or foregoing patents but will function s factorly with other cable code transmitters, regenerators and pulse selectors.

The cable transfer relay 23S is normally in the released condition indicated to connect cable code tape transmitter 253i to the cable relay transmitter comprising relays 2S and In Fig. 2 the cable code tape transmitter, which is Well known in the art, is shown enclosed in a rectangle 26E. The three-condition code is perforated in a tape 2li2 and the tape is red by the well-known tape feed mechanism indicated by a rectangle 2&3, over the code element sensing pins 204 and 235. When a particular signal element is represented by a perforation the tape the corresponding pin is admitted through the perforation to close its associated Contact. When a particular signal element is represented by an unperforated element in the tape neither of the two sensing pins is admitted and their associated Contacts remain open. Contact 223 under control of rotatable curbing and transmitting caro 222. For an interval, equal to one-fourth the period of rotation of cani 22S, during which interval the tape is feeding and the pins may change their positions in accordance with the perforations, contact 223 is open as the cam fo1- lower engages the depressed periphery of 229. After the pins are positioned the cam ich lower is raised and contact 223 is closed. It will be made apparent below that during the interval while contact 223 is open both relays 238 and 25? are in the released condition. This applies ground to the cable for a short interval between signal elementsto discharge the cable. This is known in the art as curbing.

The armatures of the cable transmitting relays 208 and 239 are biased to the positions indicated by the effect of current flowing from bat- .tery 2in through resistance 2| I, bottom winding of Vrelay 263, bottom Winding of relay 293 and resistance 2|2 to ground. When neither onerof contacts 205 and .297 is closed the armatures loi relays 268 and 269 remain in the positions cated. For this condition a circuit be traced from ground through Contact 253, armature of relay 209, contact ZIE, armature oi relay 23B and through conductor 2l? which extends through cable 2| 8. The ground when transmitted during the proper interval for a signal element controls the regenerative repeater 2|3 in a well-knownrmanner to impress a corresponding signal element on cable code receiver 22 i. When ground is connected to conductor 2|? during the curbing interval the cable is dischargedA e well-known manner.

If contact 228 is closed a circuit may be traced from ground through battery 222, lcontact 2..-3, sensing pin 28e, contact Zilli. resistance 24-2, con Q to ground, actuating the armature of relay to the left to engage contact 2M. A circuit may then be traced from battery 223 through Contact 2M, armature of relay 292 and contact 2|5 to conductor 2 l? from where it extends over path through regenerative repeater 2|3 which impresses a corresponding signal on receiver 22 i.

If contact 20? is closed a circuit may be traced from battery 222 through contact 223. sensing pin 235, Contact 201, resistance 242, contact 223. top winding of relay 268 and resistance 22? to ground, actuating the armature oi yrelay 225 to the left to engage contact 2|6, which connects positive battery 228 through contactlili to conductor 2H, from where it extendsover a path 4 heretofore traced. Thus a signal element which is impressed on the submarine cable may be of any one of three conditions, namely, po ve bf terr, negative battery or ground. Successive si? nal elements in accordance with the cable code are used to dene each character.

Normally, as mentioned above, the three-ccnclition cable code cape transmit ci is connested to the three-condition cable transmitting relays 253 and il. Relay 23% is in the released condition and green lamp 23E is lighted ov r au obvious circuit through contact 232 or rel 23@ to indicate that tape transmitter 23 is con nected to the cable.

The circuits are arranged so w is any message to be transmitted iro element, two-condition system of i, a in Fig. 1 is closed to operate relay Tins connects the cable code tape trcnsinitt from the relay transmitter compril and 26S and connects the rive-selen.A

l to the relay transmitter.

The relay transmitter comprising; and 20S which is arranged to generate th dition signals, always remain connected th cable. When signals generated in the riva-eleinent system are to be transmitted, the cable relay transmitter is iirst switched sc as to be connected to the system of Fig. 1. Then since at the distant cable terminal the cable .is normally connected to the cable code receiver 252i it is necessary to disconnect receiver 22 and con-- nect the receiver to the receiving retranslator per Fig. 3. This is done automatically by transmitting a special train or signal elements which ates a switching device at the distant receiving end of the cable to connect the cable to the retranslator per Fig. 3. After this has been accomplished transmission from Fig. may proceed. But since the signals originally generated ip A' system per'Fig. l are iive-ele1nent twoeond signals it is necessary to translate them into 'fourelement three-condition signals berore they are .impressed on the relay transmitter` conirrising L t cic y relays 208 and Zilli. After the translated are transmitted over the cable and directed into the retranslator receiver per Fig. 3, they are retranslatedr in the apparatus of Fig. 3 to their original form and transmittedover a rive-element system connected to the retranslator. The manner in which the foregoing is performed will now bev described in detail.

Refer now to Figs. 1, 2 and 3. Normally relay m3, Fig. l, is in the released condition. Contact I4 is closed. Relay |5 is thus operated over an obvious circuit through contact H4. Contact HE is thusv open and ground is disconnected from start magnet Hl. Switch |31), which is open, is first closed connecting power supply I3! to motor |32. Motor |32 rotates driving shaft |33. Worm gear, |35 rigidly connected to the driven motor shaft, spur gear |36 rigidly secured to distributor shaft |22 and distributor shaft |22 are coupled to driving shaft |33 through friction clutch |34. Cams |2I, |2, and rotatable arm |31 of the vfour-element transmitting distributor |38 are rigidly secured to shaft |22. The driven portion of the mechanism is prevented from rotating by the right-hand end oi lever ||8 which is interposed in the path of raised shoulder H2B on the periphery of cam |2| under the influence of spring H9 which is attached to the right-hand end of the lever. Shaft |22 is normally stopped in s ucha position that continuous conducting ring |39 of distributor |38 is connected through brushes |40 and 14| to distributor segment 3. Cam |24 is in the position indicated. Contact 123 is closed. Relay |25 is operated as shown from battery supplied through contact |23. The armature of relay 126 is actuated to the right to close contact |21 under the influence of the flow of biasing current through the bottom winding of relay |26 over an obvious circuit.

When signals generated in the ve-element system are to be transmitted, start key is operated. A circuit may then be traced from battery through resistance |02, winding of relay |03, tape lever contact |04, switch conductor |10, and the winding of relay 230, Fig. 2, to ground, operating relay 230. It is pointed out that tape lever |04 is controlled by tape |01. When there is suicient slack in tape |01, due to an accumulation of punched tape, lever |09 is lowered and contact 104 is closed. When tape |01 is taut lever |09 is raised and contact |04 is opened to stop the operation of the transmitter distributor. This mechanism is well known in the art. It is disclosed in Patent No. 2,055,567, E. F. Watson, Sept. 20, 1936.

The operation of relay 230 opens contacts 232,

224 and 225 and closes - contacts 236, 233, 234 and 235. The opening of contacts 224 and 225 disconnects the cable code tape transmitter 201 from the transmitting relays 208 and 209. The closing of contacts 234 and 235 connects the operating windings of relays 208 and 209 to conductors 112 and I |3 which connect the cable relay transmitter to the five-element transmitting system. The opening of contact 232 extinguishes lamp 23|. The closing of contact 236 establishes a circuit from battery through contact 236, resistance 231, and the winding of relay 238 to ground, operating relay 238. Contact 243 closes. This establishes a circuit from battery through contact 249 of key 24|, lamp 242, contact 243 and the winding of relay 238 to ground. This locks relay 238 under control of key 241 and lights red lamp 242 as an indication that the cable relay transmitter comprising relays 208 and 209 is connected to the five-element system. While relay 238 was.

released no battery was supplied through contact 239 to a magnet control of the tape feed mechanism 203 of transmitter 20|. The closing of Contact 239 connects battery to the magnet of tape feed mechanism 203 and the feeding of tape through transmitter 201 stops immediately. The rotation of transmitting and curbing cam 229 continues. Cam 229 in addition to controlling the length of a signal impulse transmitted over the cable and controlling curbing cooperates in the performance of another function, viz., to time the signals sent from the transmitter of Fig. 1 including the transmission of a train of impulses over the cable 2|8 to switch the receiving end of the lcable from the cable code receiver 22| to the receiving retranslator per Fig. 3. The manner in which this is performed will now be described.

It has been explained that whenever the cable relay transmitter is seized yby the five-element system, per Fig. 1, a special train of impulses is transmitted over cable 218 to switch the receiving end of the cable from the cable code receiver 22| to the receiving retranslator per Fig. 3. This is done automatically in response to the seizure of the transmitting end of the cable by the operation of start switch |01. When relay |03 is operated upon the closure of switch and contact ||4 is opened, battery is disconnected through conm cam 229 closes contact tact |14 from the winding of relay ||5 and relay 15 starts to release to operate start magnet ||1 and set the transmitting distributor |38 in operation. Relay |15 however is a slow-to-release relay. During the interval while relay 1|5 is releasing, and before distributor |38 is set in operation, a train of at least six positive impulses is impressed, in a manner to be described hereunder, through cable 218 on the six-pulse selector 250 to perform the switching function.

When the path through the top winding ci relay 209 is transferred irom contact 22:1: to 2342, the top winding of relay E33 is deenergized as each of the parallel branches connecte to conductor i12 in Fig. l extends to an open circuit at this time. The armature of relay tiereiore remains in engagement with contee 'BES under the influence of its biasing winding while the six switching pulses are bei. g transmitted. When 3, with relay 230 0ptra-ced from battery 222 erated, a circuit may ce through contact contact 233, conductor lll, top winding of relay inner solid conducting ring |39 of distributor i323, conducting brushes |40 and 14| ci rotatable arm lil, segment 3 of 30 close Contact 2i transmitter |38, conductor 280, contact |82, ccntact 143, Contact conductor 23, Contact 23.5, top winding of reay S and sistance 221 to ground. The armature oi relay is actuated to The armature ci `polar relay |23 is actuated to the lett but it is ineffectual at this time. When contact 2 l is closed positive pulse is impressed on conductor il. st positive pulse continues as long as Contact 223 remains closed. When cam 229 has rotated so that its follower engages the depressed port-ion of cam 22S, contact 223 opens, the top windings of relays 288 and |26 are deenergized, the armature ci relay 20B is operated into engagement with Contact li.

@Ground is connected through contacts 2i3 and battery each followed by a short grounded interval are transmitted through contacts i 0 and E i5 respectively. In response to successive pulses oi positive battery the six-pulse selector which is well known in the art, closes Contact 2"". This establishes a circuit from positive battery' through contact 25| and the winding of relay 252 to ground, operating relay 252. The closing of col.- tact 253 establishes a circuit from battery through contact 264 in the six-space selector Contact 253 and the winding of relay 252 to ground to maintain relay 252 operated. Relay 252 will remain locked in the operated position until the transmission from Fig. l is terminated when the six-space selector will be operated by the transmission of a train of at least six-spacing or ground pulses to open contact 255|. This will be described more fully hereunder.

Contacts 251i and 220 through which receiver 22| was connected to the cable circuit are nov; opened from the operation of relay 252 and contacts 255 and 255 are closed. A circuit may then be traced from the armature of relay .l through contact 258, contact 253, and conductor 259 through the top winding or" relay 38| to ground. A circuit may also be traced from Contact 260 of relay '25? through contact conductor 2% i, and the top winding of relay 332 to ground. The circuit is now in condition to direct impuls transmitted over cable 2id through regent ive rc pcater 219, and contacts 55 and 2 5 to polarized receiving relays 35| 3522 of Fig. 3. Thearmatures 'of relays 35i and 362 are normally Vactuated to their right-hand positions under the influence of :current flowing through their biasing circuits which may be traced from negative battery through the bottom winding of relay 35| and the bottom winding of relay 3W to positive battery. As positive battery is connected to contact 25S andcontact 255i through the operation of polar relay 251 of regenerative repeater 2id in response to the positive and negative impulses received over the cable, the armatures or" relays 36| and 362 will be actuated to their left-hand positions. In response to a ground signal element, as distingus ed from curbing ground, contacts 258 and 259 will both be en and the armatures of relays 3U! and 302 will both be actuated to the right. The cable code regenerative repeater which receives the cable code signals to perform these functions together with the six-pulse and sixspace selectors are all Well known in the art and Will not therefore be described in detail herein.

To return noW to Fig. l. After the six or more switching pulses have been transmitted over cable 2|8, relay H5 will be sufficiently deenergized so that contact Ht will close. On the next closure of Contact |21 when 229 causes an opening of Contact 223, a circuit may then be traced from Y ground through contact tit, contact |21, arma-1 4 the circuit which has been traced from battery 222 in Fig. 2 to ring |35 is extended through brushes il! and 55|, segment conductor |19, Contact itil, conductor i2, contact 235i, top 7vinding of relay 223.8 and resistance to ground operating the armature of relay 255 to the left. This transmits a negative battery over cable 2H to start distributors 352 and tilt in a manner to be described below.

TheL transmitting and curbing cam 229 in the present embodiment is fork-driven at a speed of y,

140 revolutions per minute. The transmitting distributor |38 is driven at a speed of 150 revolutions per minute. The difference in operating speeds of the two transmitting mechanisms is adjusted by arresting the rotation of rotatable arm |31, once in each revolution. The stop Cam is arranged so that arm |31 is stopped approximately in the position shown near the righthand end of segment 3 of the distributor. Once start magnet l1 is energized and the right-hand end of lever H8 is disengaged from shoulder |25) of stop cam 12| shaft |22 cannot be arrested until shoulder |2ii of stop cam |2I' is in position to reengage the right-hand end of lever H8. To anticipate, the armature of relay |26 will be actuated to Jrhe left to disengage from contact |21 during the first three-quarters of each rotation of cam 229. This opens the circuit of magnet H1 and the right-hand end of lever H8 is interposed in the path of the shoulder |20 of cam V|2i under the influence of spring H9 once for each signal element transmitted. However, this is ineffective until the shoulder |23 has rotated into the stop position near the end of the third pulse. When the third pulse is being transmitted and the armature of 'relay |26 is actuated to the A left, start'magnet ||1 Will berdeenergized and yin the raising of the right-hand end of the lever will be eiective to arrest the rotation of the arm |31 of the transmitter distributor |38. As cam 22s continues its rotation Contact 223 is opened, the top Winding of relay |26 is deenergized, the operating path for start magnet ||1 is reestablished, lever H8 is disengaged from shoulder |20, and the rotation of shaft |31 resumes. The rotation of the shaft will be arrested once in each revolution and the delay interposed will be just suilicient to compensate for the difference in operating speeds 'of the tWo mechanisms.

Teletypewriter station |55 which is remote from the transmitting code translator is connected by means of conductors |5| and |52 to the typing reperforator |38. As the teletypewriter contacts |53 are operated live-element current and rio-current pulses are transmitted over a circuit which extends from the negative terminal of battery i5@ through break key |55, teletypeW-riter transmitting contacts |53, receiving magnet |56, conductor l5|, reperiorator magnet |51 and conductor l 52 to the positive terminal of battery |54. :In the present embodiment of the invention the dye-element current and rio-current signals are transmitted Yfrom the teletypewriter to define each character at the rate of 60 Words per minute. The transmitter distributor transmits the cable code combination at a speed of 23.4 Words per minute. While the teletypewriter is operating, tape will accumulate. Each character is deiined in the tape 01 as a combination of five '.35 perforated or unperforated elements arranged transversely in tape |51. The tape is fed into the transmitting distributor and interposed between pins |53 and |62 and their respective contacts 453 to |51, inclusive, in a Well-known manner.

:40 Where an element in the tape is punched the corresponding contact is closed and where an element is unpunched the corresponding contact is open.

When contact itt is closed a circuit may be traced from positive battery through sensing rpin 58, contact I 63, and the Winding of relay |68, loperating relay 62. When contact |64 is closed a circuit may be traced from positive battery through sensing Jin |59, contact |55, and the winding of relay |69 to ground, operating relay M59.. When contact |65 isv closed a circuit may be traced from positive battery through sensing pin |50, contact |65, and the Winding of relay HE to ground, operating relay |10. When contact it is closed a circuit may be traced from positive battery through sensing pin |5|, contact it, left-hand Winding of relay |12 and, when contact |13 is closed, to ground through contact 13, operating relay |12. When contact |61 is closed a circuit may be traced from positive battery through sensing pin |52, contact |61, lefthand Winding of relay |1| and, when contact |13 is closed, through contact |13 to ground, operating relay 11|. When Contacts |53 to |51 are open the corresponding relay of the group I 58 to |12 will not operate.

The tape is drawn into position so that all of the punched and unpunched areas in a particular transverse section representing a particular symbol are sensed simultaneously by pins |58 to |62. The pins are Withdrawn While the third pulse i-s being transmitted and the succeeding transverse tape section identifying the nest character is moved into position so that the elements may be sensed by the pins before rotatable arm |31 sweeps onto segment I. Elements i, 2 and 3 in the tape control relays |68, |69 and F1o. These relays cooperate as a group. It will be made apparent below that when the rst element of the four-element code is transmitted the circuit extends from the transmitting cam 229 through segment I of transmitter |38 through a path which when closed extends through a combination of the contacts of relays |68, |69 and |18 to either conductor I I2 or I I3 which controls relays 298 or 289 so as to transmit either positive battery or negative battery. If the path through the contacts of relays |68, |69 or |10 is open relays 208 and 299 connect ground to the cable for the particular signal element. When rotatable arm |31 sweeps onto segment 2 of distributor |38 the path extends from transmitting cam 229 through segment 2 of distributor |38 and through a certain combination of the contacts of relays |68 to |19 to conductor |I2 or I|3 to control relays 208 and 299 so as to transmit either a positive or negative pulse or, if the path through the contacts is open, ground as the second element of the four-element cable code. Thus the first three elements of the ve-element code control relays |68 to |10 in a manner to produce two signal elements each of which may be of any one of three conditions depending upon the settings of relays |68 to |19. The fourth and fifth elements of the live-element code set the armatures of relays |1| and |12 which cooperate also to establish various combinations of closed paths or open circuits through the contacts of these re lays in tandem to conductors I2 and I I3 and relays 298 and 299. When rotatable brush arm |31 sweeps onto distributor segment 3 the circuit from the transmitting cam 229 will be extended through various combinations of the contacts of relays |1I and |12 in tandem t0 conductor II2 or I I9 to control the settings of relays 208 and 209. Positive or negative battery or ground will be transmitted for the third pulse of the fourelement cable code. When rotatable brush arm |31 sweeps onto contact 4 of transmitting distributor |38 the circuit from transmitting cam 229 will be extended through various combinations of closed or open circuit paths through the contacts of relays |'1| and |12 in tandem to conductors ||2 or |I3 to control relays 208 and 299 so as to transmit either positive or negative battery or ground as the fourth pulse of the cable code combination.

The transmitting tape as has been explained is presented to the sensing pins so that all five elements in the tape may be sensed at the same time. Relays |98, 189 and |19 corresponding to the first three elements of the five-element code are controlled substantially instantaneously, as soon as the pins are set in position and remain under direct control of the sensing pin contacts only, as the pins remain in their selected positions throughout the entire interval while the nrst two cable code elements, into which the first three elements of the five-element code are translated, are being transmitted. In tracing the operating circuits for relays ill and |12 which cooperate to determine the nature of the third and fourth elements of the four-element code, it was pointed out that in order to operate relays I1| or |12 contact |13 must be closed. Relays |1| and |12 cannot be operated until relay |25 is released to Close contact |13. After the No 4 pulse of the preceding four-element combination is sent, contact |23 is opened. Relay |25 releases and relays |1I and |12 are set in whatever position is necessa-ry in accordance with the fourth and fifth elements of the tape code combination which is presently being transmitted. Contact |23 is opened after the fourth signal element of the four-element code for the preceding character is sent. Relay |25 releases closing contact |13. Relays I'Ii and |12 are operated or remain released in accordance with the fourth and fifth elements of the live-element code. The sensing pins are withdrawn while the third element of the four-element code is being transmitted. But before the pins are withdrawn, relay |25 is again operated to establish a locking circuit for relays |1| and i12. The locking path extends from battery through Contact |16 and the right-hand windings oi' relays |11 and |12 in parallel to ground. Contact il closes before contact |13 opens. Thus even though the sensing pins are withdrawn before the transmission of the third element of the four-element code is completed, the paths through the translator circuit which determine the nature of the third and fourth pulse of the four-element code are maintained until the transmission of the third and fourth element is completed.

Refer now to Fig. 4. In the code tabulation per Fig. 4 at the upper left is shown a code tabulation entitled 5 Unit and at the upper right a code tabulation entitled 4 Unit. In the 5 Unit tabulation there are three vertical columns of -land symbols. In the 4 Unit tabulation there are two vertical columns of J.- and 0 symbols. The group of symbols in each horizontal line of the upper left-hand vertical tabulation corresponds to a different combination of the rst three elements of a five-element code. There are eight possible combinations of -land symbols that can oe formed out of three elements each of which may be or The 4 Unit tabulation shows, on a corresponding horizontal line, the two three-element symbols of the 4 Unit code into which the three two-element symbols of the 5 Unit code are translated in the invention herein. At the lower left of Fig. 4 is shown a code tabulation having a heading 4 5 and at the lower right is shown a code tabulation having a heading 3 4. The heading 4 5 represents the fourth and fifth elements of the live-element code. The heading 3 4 represents the third and fourth elements of the 4 Unit code. Under the heading 4 5 are shown the four possible different combinations of -land elements corresponding to the fourth and fth elements of the 5 Unit code. On a corresponding horizontal line under the heading 3 4 are shown the symbols in the 4 Unit code into which the fourth and fifth elements of the 5 Unit code are translated. Attention is called to the fact that in the 5 Unit code there are but two kinds of symbols, viz., -land representing the current and rio-current condition of each of the five elements of the fiveelement code. 'Under the 4 Unit code there are three kinds of symbols, viz., -l-, and 0. -lstands for positive battery, represents negative battery, and 0 represents ground on the 4 Unit cable code.

The various paths through the five to fourelement relay translator shown in Fig. 1 for the code translations indicated in Fig. 4 will now be traced.

First, the translation indicated in the top horizontal line, that is. the translation from three elements in the five-element two-condition code to a -l and element in the four-element three-condition code will be described.

For the'three -ielements relays |63, |69 and 10 are operated as described. When contact 223 is closed a circuit may be traced from battery 222, through contact 223, contact 233, conductor top winding of relay |26, solid conducting ring |39 of distributor |38, conducting brushes |40 and iti of rotatable arm |37 of distributor |38, c011- ducting segment l of distributor |38, conductor Iii, contact i! of relay |88, contact |82 of relay 59, conductor H3, contact 235 of relay 230, top winding'of relay 208 and resistance 221 to ground, operating the armaturev of relay 208 to close its contact Zit. The path through the top winding of relay 209 is open. The armature of relay 209 is in engagement with contact 2|3 under the influence of current owing through its bottom or biasing winding. When contact 2 5 is opened the position of the armature of relay 209 does not aiect the signal element transmitted. Positive battery 228 is connected to cable conductor 2 by the armature of relay 208 as the rst signal element of the four-element three-condition code. The positive pulse continues until transmitting and curbing cam 229 has rotated into position to open contact 223. Then the top winding of relay 258 is deenergized. The armature of relay 20S is actuated to close contact 2|5 under the influence of current flowing in the bottom or biasing winding of relay 208. Ground for curbing or discharging the cable conductor is connected to conductor 2|? over a circuit which extends through contact 2|3, armature oi relay 209, contact 2|5 and the armature of relay 208 to conductor 2 I It is pointed out that the portion of the transmitting circuit extending from battery 222 to the conducting brush |4| of distributor |38 remains unchanged for the transmission of each signal element of the four-element code. In the description below the transmission path between battery 222 and brush |4| will therefore not be retraced.

When brush |4| sweeps onto segment 2 of distributor V58 the transmission path is extended through conductor |78, contact |83 of relay |68, contact |84 of relay |69, contact |85 of relay |10, conductor H2, contact 234 of relay 230, top Winding of relay 209 and resistance 240 to ground actuating the armature of relay 209 to engage contact 2M. The position of the armature of relay 208l remains unchanged. A circuit may then be traced from negative battery 226, contact 2|4, armature of relay 209, contact 2|5 and the armature'of relay 208 to cable conductor 2|'|. Negative battery is thus connected to the cable as the second element of the four-element code.

Attention is called to the fact that when the transmission path from battery 222 extends through conductor H3, positive battery is connected to cable conductor 2|'| and when the transmission path from battery 222 extends through conductor 2 negative battery is connected to cable conductor 2|'|. Attention is also called to the fact that if battery 222 is not connected to either conductor 2 o r H3, the armatures of relays 208 and 209 are both actuated to engage their respective right-hand contacts, under the influence of their respective bottom or rbiasing windings. Under this condition ground is connected, as has been shown, to conductor 2H. Ground as has been explained is connected to cable 2|? for two conditions, namely for curbing and also for the transmission of the kthird of the three signaling conditions for any one of the four elements of `the four-element cable code.

In the followim;` description only that portion of the transmitting path' extending between brush l! and conductor |612 or H3 will vbe traced. When the path extends to conductor H3 a positive signal element will be transmitted over ycon-- ductor 2|'|. When 'the path extends to conductor i l2 a negative signalv element will be transmitted over conductor 2H; When the path is not continuous to either conductor H2 or H3 the top windings of both relays 208 and 209 will lbe deenergized. The armatures of relays 208'and 209 will both be actuated to engage their right-hand contacts and ground will be connected'through contacts 2i3 and 2i5 to conductor 2H;

Now the translation indicated in the toip horizontal line of the bottom leftand right-hand tabulation under the headings 4 5 and 3 4 will be explained. ln this translation the fourth and fifth elements of the live-unit code are translated into the third and fourth elements of the four-unit code.

As explained above, the -fsymbol for the fourth element in the five-element code indicatesy the relay |72 is operated. The symbol for the fth element of the live-element code indicates that relay l'll is released.

For this condition when brush |45 sweeps onto segmentl 3 a circuit .is established which extends through conductor |88, contact 1420i relay 21|, contact |86 of relay liz-and contact |31 of relay |12 toconductor H3. This eiects the transmission of a -lpulse as the third element of the four-element code.

When brush |4| sweeps onto segment 4 a circuit is established which extends through conductor |79 and Contact |88 of relay to conductor H2. This eiects thetransmission of a pulse for the fourth element of the four-element 40 code.

Thus a live-element code consistingof the ve elements -iis translated into a fourelement code consisting of the four elements -l- The paths through the relay code translator of Fig. i for the translation of the seven other pos'- sible permutations of elements 1, 2 and 3 of the five-element two-condition code into corresponding elements and 2 of the four-element threecondition code, indicated in horizontal lines two to eight in the upper portion of Fig. 4, under the headings 5 Unit 1 2 3 and e Unit 1 2 will now be traced. Thereafter the paths for the translation of the three other possible permutations of elements 3 and e of the ve-element two-'condition code into corresponding elements 3 and 4 of the four-element three-condition code shown in the bottom three horizontal lines in the lower portion of Fig. 4, under the headings 4 5 and 3 4 will be traced.

The second horizontal line in Fig. 4 shows a group of three elements, viz. In conformance with this grouping, relays |68 and |89 will be operated and relay i'l will be released. From segment the path extends through conductor |11, contact I8! and contact |82 to conductor l i3. The rst element of the corresponding four-element code will therefore be From segment 2 the path extends through conduotor |28, contact |83, contact 84 and contact to conductor l i3. The second element of the corresponding four-element code will therefore be -I- also.

The three-element combination shown on the 'i3 third line is Forthis condition relays |38 and 10 Will be operated and relay iBS Will be released.

From segment l the path extends through conductor |11, contact .EBI and contact |9| to conductor I2. The irst four-element pulse is From segment 2 the path extends through conductor |18, contact |83, contact |92 and contact |93 to conductor H2. The second four-element pulse is also.

The combination shown on the fourth line is For this condition relay |68 Will be operated. Relays |63 and |10 Will be released. The circuit extends from segment i through conductor |11, contact l8| and contact |9| to conductor ||2. The first impulse of the four-element code is therefore From segment 2 the circuit extends through conductor |13, contact i83 and contact |32 to an open circuit at contact |83. This, as has been explained, results in the transmission of ground, represented by the symbol as the second impulse of the four-element code.

The iifth line shows the symbols -1, for the uve-element code. Relay |68 is released and relays |69 and |13 are operated, The circuit extends from segment l through conductor il?, contact |94, contact |25, and Contact |98 to conductor I2. The rst element of the four-element code is therefore `From segment 2 the circuit extends through conductor |18, contact |91, contact les and contact |99 to conductor H3. A pulse is transmitted as the second element of the four-element code.

In accordance with the code for J,- on the sixth line relays |33 and |13 are released and relay |39 is operated. From segment the path extends through conductor |11, contact 34, contact |95, and contact 4H to conductor |i3 transmitting a pulse as the irst element or" the cor responding four-element code.

From segment 2 the circuit extends through conductor |18, contact |91 and contact |38 to an open circuit at contact leg. Accordingly, ground represented by the symbol O is connected to cable conductor 2 |1 for the second element of the fourelement code.

In accordance with the code for -lshown on the seventh line, relays E38 and |553 are released andrelay 18 is operated. From segment l the path extends through conductor |11 and contact |96 to open contact |35. This connects ground, represented by the symbol 0, to cable conductor 2|1 as the first four-element pulse.

From segment 2 the circuit extends through conductor |18, contact |91, contact 48d and contact 68| to conductorl i3. The second four-elen ment pulse is therefore In accordance with the code for shown on the eighth line relays |33, |58 and |18 are released. From segment i the circuit extends through conductor |11 and contact |86 to open contact 95. Ground is therefore connected to cable 2|1 represented by the symbol 0 as the first element oi the four-ciernent code.

From segment 2 the path extends through conductor |18, Contact Edi, contact 233i! and contact 402 to conductor ||2. The second four-element pulse is therefore On Vthe second line under the heading 4-5 the code -lappears. Relay |12 is released and relay |1| is operated. From segment 3 the circuit extends through conductor |88, contact 403, conifi tact and contact hifi to conductor H2. The third element of the four-element code is therefore From segment 4 the circuit extends through contact i335 to conductor l i3. The corresponding iourth element of the four-element code is therefore On the third line under the heading 1 -5 the symbols appear. Relays iii and |12 are both released ior this condition. Frein segment 3 the circuit extends through conductor |83, contact |42, contact M3, contact and resistance its to ground. Contact fit is open. This results in the connection of ground to cable 231 represented by the symbol 0 under the heading 3 4 as the third element of the four--elenient code.

From the fourth segment the circuit extends through conductor i'lzi contact |88 to conductor i i2. The fourth element of the four-element code is therefore One the bottom line under the heading 2 5 the symbols -iappear. Relays ill and |12 are both operated for this condition. From segment 3 the circuit extends through conductor E38, contact 463, contact dit, contact sul and resistance |83 to ground. Contact i3d is open. This results in the connection ol? ground to cable 2|1 represented by the symbol 0 under heading 335 as -the third element oi the four-element code.

From segment i the circuit extends through conductor |13 and contact 65 to conductor ||3. The fourth element of the corresponding fourelement code is therefore Refer now to Fig. 3.

The four-element receiving distributor 304 in the four-to-five-elernent retranslator and the associated relay circuit, together with the transmitting distributor 333 for the five-element code made be assumed to be in the condition indicated when the apparatus is idle. Switch 331 of Inotor 388 of receiving distributor 331i and switch 325 of motor 325 of transmitting distributor Sile are closed manually preparatory to operating the mechanism oi Fig. 3. Whenever the system per Fig. 1 may be operated switches 301 and 32S will be closed. Motor 33e rotates, driving shaft 309. Driven shaft 3|@ is restrained from rotating through friction clutch 3| i, by the right-hand end of stop lever 3|2 of start magnet 3|3, which engages a raised shoulder' SIA on the periphery of stop cam 3 l 5 which is rigidly secured to 'transmitter-distributor shaft 3|i. Rigidiy secured to distributor shaft 3 5 is rotatable distributor arm 3 1. Secured in arm 3|1 are conducting brush 318 which engages the inner segmented distributor ring and conducting brush Sie which engages the outer segmented distributor ring. Driven shaft 318 is coupled to transmitter shaft 346 by worm 32e which is rigidly secured to shaft 3l@ and spur gear 32| which is rigidly secured to shaft Siti.

The rotating arm 3 i 1 is arranged to be arrested in the position indicated with brush SIS engaging segment 321 and brush SiS engaging segment 328.

The operation of the driving mechanism oi transmitting distributor S is substantially the same as that or receiving distributor 383 except that the outer conducting brush 33t is always arrested when it engages stop segment 33 l.

Attention is called to the fact that the outer ring of distributor 363 has four segments spaced and of a size to receive the center portion only of the four signal elements of the four-element code. These four segments 352, 368, 336 and 592 are relatively short.

In response to the reception of the negative :starting impulse, the armature ofi'el'ay :33| is actuated to engage contact' 353. A'cireuitinay now be traced from negative battery through contact 35S, resistance 334, conductor 335, segmentl32i, brush Sits, brush3i9, segment`r328. conn s 4ductor 335, windingof relay 331, contact relay 339 and contact 343 of relay SISI 13o-ground -operating relay 331. rIhe operationof'relaySS establishes a circuit fromzbattery through icontact 342 of relay 331, conductor 353 andthe Wind- --ing of start magnet 3| 3 to ground. Theletehand -end of stop lever 3 l 2 is raised againstthe iniiuence .ofv spring 331i attached tothel right-.hand Yend or" lever 3i2. The right-handend of lever .13:'2 is disengaged from shoulder 3Ifi. Rotatablel brush arm Si? of distributor 333 starts.torotateinza clockwise direction. The closing @contact-i345 of `relay 33? establishes a .circuit 'from "battery `through contact .345 andthe Winding of :start magnet 346 of the five-element transmittingdistributor 355. Rotatable brush arm 351 starts to rotate in a clockwise direction.

As brush 3l@ engages segment 532 correspond- -ing to the fourth element ofthe four-element code, relay 393 will not be operated,- since con- Vtact 359 of relay 33t will remain closed'and negative battery connected to contact 333 'Will voppose negative battery connected to the :right-hand Winding of relay 393.

After the start pulse is received' let itfrbeassumed that the four-element cable code `con.-

-bination comprising the two elements shcwnon the first line of Fig. 4 under the hea'dingfl-i, viz., -iand the two elements shownonthe .rst line under the heading 3-4, viz., areV Vfirst to be received over the cable. Theirstf'two elements -lof the four-element code'iareztdbe 'translated into the elements -I- -I- -l-fas the rst three elements of the live-element code andthe second pair of elements which are: the third and fourth elements of the four-element rcode are to be translated into the elements -|--11as the fourth and -fifth elements of the Je-element'code.

In other-Words, thefourfelement combination -i- I- is to be translated into the fiveeelement When brush 353 engages segment'35,"a circuit rnay be traced from positive battery* through resistance 34S, segment 333, brushes SIB ands3I-S,

Vsegment 356, conductor 35i/'and the winding-.of

relay 352 to ground operatingrelay352. Relay 352 vis a locking relay, When relay-.352 is-released battery is supplied through'contact '353 to the left-hand locking windings of relays 354,555,556

and 351. Such of these relays as have been Yoperg ated on the preceding cycle of operations,A in ac cordance with the first tWo elements of the fourelernent cable code, in a manner to .be described hereunder, will be locked through Vcontact 353, 359, 363 or 35i. releases such of these relays as'havev been'lo'cked in the previous cycle so that relays 354 to 351 are conditioned to receive and register thev nature of the rst two symbolsof the four-elementzcode.

When brush SiS engages segment 1362 the rst.

positive element of the four-.element code Will'be impressed on the translating circuit. :The'circuit extends from positive battery through contacti332, contact 333, resistance 334, conductor V335,:seg-

ment 321, conductor 333, segmentzl'SEll, brushes f .3I8 and 3m, segment 352 and conductor whichconnects in parallel to the right-handr-Wind- 'ings of relays 355 and 355 throughfrectiers366 and 361, which are oppositely poled. .RectierfSBB .presents .allow resistance torcurrentiof positive The opening of Contact `3531 are 'polarityssothat substantial current fiowsthrough i'retieri3S6larrdthe rightlhand winding-ofrelay 355i to ground operating relay 354. Rectieri-`351 presentsaan exceedi-ng'lyrhigh 'resistancei--to curfrent for positiverpola'rity sothatthel resistanee'oi the circuit extending :throughv lrectifier 351 A. the rights-hand :winding ;.of :relay I.355 ato Nground is: toes-.great to;l permit relay 355i to frbe-:energized. :Contact therefore closesfandzcontact 353:- remains open. When brush arin Sihhasrrotated tintoposition sothat brush; 329 .engagea-segment the secondi element. ofiw the .fcur-felernentcable code Willbezimpressedon the` retranslator mech- L.anisrn .Thelsccond---element ris ea* negative; element. vIn response; tothis the-armature ofI relay k.3!! I will-Abe. actuated' to .close contact 1369. l A circuit may then be traced froin'negativesbattery through .contact 369,V resistance 4331i, .conductor T335, segmentl, conductor 565,-segment'3i brushes 3 I 8 and-3 I 9, segment; 358 .and Iconductor -Sfrcm which .parallelfbranches extend. -.Qne

the parallelbranches extendsthrcugh rectier "'and the right-hand Windingwoi' relayLSSy to ground. The other parallel branch extends through rectifier' 31|.-andfthe righthandwinding of relayr3511to ground. .Rectifier319..presentsila very high resistance to currentor negative .polarity so that relay S356 remains unoperated. Rectifier'. 31 Lpresents ai lowresistanc'e'lto .current of negative polarity so that the. right-.hand Winding of. relay 351is energizedclosing contactl`36 I.

`R`elay"352 Was released whenbrusharm 311 swept beyond segmentl. .'Contact353 .was

closed, When relay '354.operated Va. circuit ,was

established frombattery'through contact 353, Contact 35S and the leftehand winding .of relay 354 rto ground`locking.relay"354. '.Whenrelay "S351 was .operated a cir-cuit was. establishedffrom battery through contact353, contactl'3Lan'd the `4,0 left-hand Winding ofV relay '351' toigground locking relay v351. "Relays`355 and'irernainediin the released condition. Y

.The distant vee'elernent Ateletypevvriterfstation arranged to receive -'ifive-eierrient'two-condition signals is connected to' transmitting 'distributor 305 atv the cable receivingV retranslating station by means. of aA pair of conductors 552 and "554. While distributor'35 inthe stop position shown, printer. magnet 313 Vis energized by current'ilowing over a circuit which extends frorn'the rightfhand .terminal of battery'35, conductor 552, Winding of printer magnet 314, conductor 545,. ring .313,

`so that the gap between inner ring313 Aan'd'segment 316 of `the transmitting distributor 'is bridged by rbrushes-32S; and'l, aVv circuit may be traced from the-'right-hand'terminal voi battery '315 through conductor 552, winding ofe'printer -rnag'net-S, conductor 554, inner' ring 333, seginentf315, conductor "311, rcontact 1318, Contact 313, and conductor 380 to the leftl-hand terminal of ba-tteryll315 whichsendsrafcurrentimpulse to the printerCorrespendingl to the--| .symbol show-n in the top line under theiheadingl--Z-S -in Fig. :'75 -4 :as the nrstfelementLof @.theriveeelement lfccde.

When brush arm 341vhas rotated into position so that lbrushes 329 and 339 bridge the gap between in er ring 313 and segment 39| of the distributor a circuit may be tracedrfrom the right-hand terminal of battery 315 through conductor 552, winding of printer magnet 314, conductor 554, ring 313, brushes 329 and 330, segment 38|, conductor 382, contact 383, contact 384,*and conductor 380 to the left-hand terminal of battery 315. This transmits another current impulse, represented by the symbol as the second impulse of the ilVe-element code.

When brush 330 engages-segment 385 a circuit may be traced from the right-hand terminal of battery 315 through conductor 552, Winding of printer magnet 314, conductor 554', ring 313, brushes 329 and 330, segment 395, conductor 336, contact 381, contact 388, and conductor 380 to the left-hand terminal of battery 315. This transmits a third positive pulse, represented by the symbol -l, as the third element of the veelement code.

Attention is called to the fact that the first two elements of the four-element code, namely the -lelements, have been translatedinto the rst three elements of the five-element code, namely, the -l- -i- -lelements.

When brush arm 3|1 of distributor 303 rotates into position so that brush 3|9 engages segment 369 a circuit may be traced from battery through resistance 399, segment 390, brushes 3|8 and 3|9, segment 389, conductor 390 and the winding of relay 39| to ground operating relay 39|. When contact 392 of relay 39| is opened the locking circuit, which has 'been maintaining relays 393, 394 and 395 in positions in accordance with the third and fourth elements of the preceding fourelement code transmitted over the circuit, is opened andrelays 393, 394 and 395 are released to assume positions in accordance with the third and fourth elements of the four-element code presently being transmitted.

The third element of the four-element code is a element. In accordance with this the armature of relay 302 will 'be operated to close contact 332. The armature of relay 30| will be inengagement with contact 333. A circuit may then be traced from positive battery through contact 332, contact 333, resistance 334, conductor 335, segment 321, brushes 3|8 and 3|9, segment 396, and conductor 391 to parallel branches. One parallel branch extends through rectiiier 398 and the right-hand winding of relay 394 to ground. The other parallel branch extends through rectifier 500 and the right-hand winding of relay 395 to ground. Rectifier 398 is poled so as to present low resistance to current of positive polarity. Rectifier 500 is poled so as to present exceedingly high resistance to current of positive polarity. Relay 394 is operated. Relay 395 remains released. When brush 3| 9 sweeps 01T segment 389 the operating circuit of relay 39| is opened. Contact 392 therefore closes. When relay 394 operates, therefore, a circuit is established from battery through contact 392, contact 50|, and the left-hand winding of relay 394 to ground locking relay 394 in the operation position.

The fourth element of the four-element code is a element. In response to this the armature of relay 30| is actuated to close contact 369. A circuit may then be traced from negative battery through contact 369, resistance 334, conductor 335,. segment 321, segment 502, conductor 503 andv the right-hand winding of relay 393 to negative battery. Attention is called to the fact that negative battery is connected to both ends of this circuit. Relay 393 therefore remains in the released condition as shown. Relays 393, 394' and 395 cooperate to determine the nature of the last two elements or the fourth and fifth elements of the five-element code.

When brush 330 of transmitting distributor 305 engagesv segment 505 a circuit may 'be traced from the right-hand terminal of battery 315 through conductor 552, Winding of printer magnet 314, conductor 554, ring 313, brushes 329 and 330, segment 505, conductor 503, contact 501, Contact 508 and conductor 509 to the left-hand terminal of battery 315. This transmits a current pulse, represented by a symbol, as the fourth element of the five-element code.

When brush 330 engages segment 5|9 a circuit may be traced from the right-hand terminal of battery 315 through conductor 552, Winding of the printer magnet 314, conductor 554, ring 313, brushes 329 and 330, segment 5|0 and conductor 5|| to contact 5|2 which is open. As a result of this negative current pulse, represented by the symbol is transmitted to the printer as the iiffth element of the live-element code.

When brush 330 engages segment 33|, the rotation of the distributor arm 341 is stopped. For this condition, the circuit through the Winding o of the printer magnet is again closed over a circuit heretofore traced.

From the foregoing it should be apparent that when the iirst element of the four-element cable code is positive, relay 354 is operated and relay 5 355 is released. When the rst element is negative, relay 355 is operated and relayr354 is released. When the second element of the four-element cable code is positive, relay 356 is operated and relay 351 is released. When the second ele- 40 ment is negative, relay 351 is operated and relay 356 is released. When the third element of the four-element cable code is positive, relay 304 is operated and relay 395 is released. When the third element is negative, relay 395 is operated and relay 394 is released. When the fourth element of the four-element cable code is positive, relay 393 is operated. When it is negative, relay 393 is released.

The manner in which the first and second elements of the four-element cable code shown on lines 2 to 8 under the heading 1 2 in Fig. 4 are translated into the three symbols for the first, second and third elements of the five-element Vcode shown on the corresponding lines under the heading l-2--3 of Fig. 4 will now be described.

Elementsl and 2 of the four-element code shown on the second line are -l- For this condition relays 354 and 358 Will now be operated. Relays 355 and 351 Will be released. For the first eement of the ve-element code, a circuit extends from the right-hand terminal of battery 315 through conductor 552, winding of printer magnet 314, conductor 554, solid conducting ring 313, brushes 329 and 330, segment 316, conductor 311, contact 5|8, contact 384 and conductor 380 to the left-hand terminal of battery 315. The circuit is continuous. A current pulse represented by the symbol will, therefore, be transmitted as the first element of the ve-element code. For the second element, a circuit may be traced from the right-hand terminal of battery 315 through conductor 552, winding of printer magnet 314, conductor 554, ring 313, brushes 329 and 330, segment 38|, conductor 382, contact 5|9,contact 388 and conductor 380 to the left-hand terminal of choosen@ battery V3115. The/second symbol =wil1, therefore,

from `the -rig'hthand terminal of battery 31?? through conductor -552f-Winding of "printer magnet 3M, lconduc'ztorf55e',fring 373,bru`she`s 329oan'd 335, segment '385, 'conductor '1386, `contact' 52B and contact 52! to Contact cwhichis'open. AJ.Since the circuit to Athe left'hani terminaleoflbattery '.'iis not continuous, anoecurrentpulserepresented-by the symbol willsbe'transniitted as-the third element of theve-elernentcode.

On vthethird line under vheading 1--2 -of the four-,element code the symoolsappeain For ths'condition relays 35 andi'! -Will vhe 'operated. lRelays 354 'ands willberelea'se'd. 'Attention'is called tothe-'fact that' the fcircuitlforfthe printer magnet "entends r`always ffrom the Vrifgfhthand terminal of "battery i315' through'con-ductor 552, -Winding *of "printer 'magnet 3M, f conductor 5ML-solidconductingrin'g'373,"and brushes Y"329 s.;

and 33o to someone-ofthe segmentsonthes'outer ring oidistrihutor 3BE. jIn'trac'zingithecircuitsffor vthe remainder of the translations, in "orderito avoid` unnecessary ='repetition `the description hereunder;only thatportionofithe circuit beyond the particular segment enga-gedbybrush l-i'will be'traced. YWhenhrushfifltengagessegment 315, the circuit `extends through conductor l STI, contact '5 i E5, `Vcontact; "5ivand conductor 3351 Lto .the left-hand Lterminal Vof 'battery 375. .A -l pulse will, therefore, be transmitted to the'rstelement. From' segment 38 Lia-circuit extendsV` through conductor 2382 and Ucontact i383to'contact38ll Vwhich is` open ,at 'this ztime. A-:no ecurrentpulsefrepresentedby the symbol -,iwil1,"thereore,`ibe'trans- Initted jas' the second element of *the 4fiveselenien't code. 'From' contactt' acirCuitextends through conch/actor `w3815, Contact 522,'*contact1523and 'conductor 1385 to Lthe "leftfh'and-terminal of *battery 315. "A Vv-l- Vpulse Will,l therefore, )be transmitted asathird-element of the iiVe-'element code.

On the fourth lline underitheheading 41-7-2 of thefoureuntecode, thesyinbols Q appear. -Relay 35'5'Wll-be operatedhyjthe -rpu'lse lhearman ward the right fcrthe zeropulse. .Relays `35Saird S5? wilL'thereiore; both bec'reieas'ed. "From/seg,- ment Slt the circuit extends through "conductor 3E?, contactiili, 'contact 525,;contact5zp'and'oonuctor 'Sett to "the left-"handterminal :of .v battery `-325. This resiilts. in a currentplse,.represented the' symbol -lthe' first. element of itheiveelement code. From segment '38 Ifacircu'it extends throughconductor toopencircuits at contacts '383,"5119, 52'! and528. Ano-'current pulse represented-bythe symbol will. be transmitted asthe second elementof theveeelementnode. =From segment 385 a. circuit extends through; conductor bol -`will be'transmitte'd asthe .third element of the yfive-element code.

On'the fifth lineunder'the :headingil--12 ofthe `four-unit code thersymbols appear. Forithis condition, "relays 355 vand' `will be joperated.

Relays 35s and '35? 4willbe-released. Fromseg- -inent'i acircuit'extends:throughonductorf'l and Contact Av-5 i8 'to wvopen 'contactl 'The first element of theve-element codeissthereore A current pulse"representedrbypthesymbol -lwill be"transmitted as't'he second element-*'offth'e'iiveelement code. `v:From 'segment 31385 fa Aeli-crut -extends through :conductor 386, L'contact '5529, ^con tact 523 A'and"conductor `'38l 'to the lefthand "terminal oil-batteryl. A. currentpulse represented bythe symbol #ieyiill2 bertransrnitted as fthe third element-fofthefveelementfcoiie. i A

VvThesixthdine-under the head-ing'fl-i-2 for-the four-unit code shows the-combination -i-G. For this condition, -relay' 5`42Wi-ll befoperated andre lays S55, '6fan`d3`5'i'will befreleased. ='From'-'seg ment 3316 vfa circuit Iextends through rconductor Z'rl tof openfcontacts I'on-*relays 2351, `"3% and 355. A l no-z'current f plse represented by the V'symbol Willf'be transmitted as the rst-'elementof gthe correspondingfiive-element code. From-segment 3s i fa circuitfeiztendsithrougi'rconductoriSleenta'ct 528, v-,contact VS525;'coritzmt f 52 6 'and f conductor current-pulserepresentedbyFthe symbol t{ will be transmitted-asthev` secon'dfelem'ent of the'veelement'fcode. -`From-`segment v385 a circuit extends through conductor 386 to open contactson relays '1357 landrt. IA rio-current pulse representedfby-'the symbol -Awill,'thereforejbeitransmitted vas? the third/element :of -the 4v-veelen^ient code.

The seventh line under'the' headingll-Zloffthe fourelement-codef'shows the symbolsiO ,-i- Nas Vthe first f and second -elem'ents of ithe four-element code. @Forl'this condition, relay--S'Siyvillbe op erated. -Relays Ir3551!, l'355and"ibwillbe released. Fromfsegment-'STG-"a circuitsextends through conductor 317 #and contactfl'' to Nopen Contact $385,. LA "no-current igpu'ise represented .by A'the 'symbol Willfbei transmitted `-as "'thetrs't' element of `the five-element tcode. From `segment "33| a circuit l40 second elementsof"theithree-element code. From segment385 'a ycircuit:extends':through-con'ductor 38B, Contact 52B, Contact "521 .contact '522 and conductor "336 toithe llet'hand 'terminal 4of battery"35. 'A current ,pulsefrepresented by wthe symbol +lwlillbeitransmitted.as .the third element Lofthe five-element code.

'Gn the A,h-lith line underthey heading Vfoi- I2 7or theV ibmelement 4` code ithesyrbls .0 -sappeaix For thiscondit-ion, relay 35? will, be operated fand relays 3,554, anfd 56 will he; released. From segmentm'i6-a,ci1'cuitextendsuthroughconductor @Ti @to contacts/i5 t6 :and -318 in parallelhoth :of whichieadto openfzcircuits. -rn-rno-.ourrentzpu-lse v represented hy'fthe y.symbol --fwillhetransmitted as the -first ielementtoi theg'iiveeelement icode.

From Vsegmento-8 ha .fc-ircuitvfextends through conductor 332-, and econtactill! tto openoontaots 151,8 'and r3 84. ,Azfno+currentpulsesrenresented. iby .the symbol :Willlhe transmitted asithe fseoon'd-felevnient of the .inve-element scode. lFromfseen-ient branch :which rextends from jfc'ontact`522 "terminates vat Yonen fcontacts'f'z fandfEZS. noe'current pulse represented by .the vsymbol f "Will,

therefore, IV"tre transmitted 'as "the rthird .element of `theiveelem-entfco'de.

The Iman-nei" inwhich frelaysii', '384 and cooperate*toetransiatethethird and fourth 'elements; of tlrejfourY-element .coderintojthefourth 21 under the headings 3-4 and 4--5 of Fig. 4 will now be described.

The second line under the heading 3-4 shows the symbols as the third and fourth elements of the four-element code. For this concondition, relays 395 and 393 will be operated. Relay 394 will be released. From segment 505 a circuit extends through conductor 50S and contact 530 to open contact 53|. A no--current pulse represented by the symbol will be transmitted as the corresponding fourth element ofthe veelement code. From segment 5|0 a circuit extends through conductor 5||, contact 5|2 and conductor 509 to the left-hand terminal of battery 315. A current pulse represented by the symbol will be transmitted as the iifth ele ment of the five-element code. I

The third line under the heading 3 4 shows the symbols as the third and fourth elements of the four-element code. For this condition, relays 393, 394 and 395 will all be released. From segment 505 a circuit extends through conductor 506,'contact 530 and contact 53| to open contact 532. A no-current pulse represented by the symbol will be transmitted as the fourth element of the five-element code. From segment |0 the circuit extends through conductor 5|| to open contact 5|2. A no-current pulse represented by the symbol will be transmitted for the corresponding fth element of the ve-element code.

The last line under the heading 3-4 of the four-element code shows the symbols 0 -las the third and fourth elements of the four-element code. For this condition, relays 394 and 395 will both be released and relay 393 will be operated. From segment 505 a circuit extends through conductor 506, contact 530, contact 53|, contact 532 and conductor 509 to the left-hand terminal of battery 315. A current pulse represented by the symbol will be transmitted as the fourth element of the five-element code. From segment 5|0 a circuit extends through conductor 5| contact 5I2 and conductor 509 to the left-hand terminal of battery 315. A current pulse represented by the symbol will be transmitted as the corresponding element of the five-element code.

Each one of the eight combinations of the rst two elements of the four-element code may be combined with each one of the four combinations of the second two elements of the four-element code to provide thirty-two different four-element combinations. Each one of the thirty-two different combinations of the four-element code may be translated into a different one of the thirty-two different possible combinations of the rive-element start-stop code as indicated.

It was explained above that when the cable relay transmitter was seized for the transmission of signals generated in the system per Fig. l, red lamp 242 was lighted and the cable code tape transmitter 20| was stopped. The cable code tape transmitter is arranged so that when the start key |0I in Fig. l is opened, releasing relay 230 of Fig. 2 and reconnecting the tape transmitter 20| to the cable relay transmitter, one or more groups of six successive ground pulses will be transmitted over the cable before the cable code transmitter is restarted manually. Such a combination never occurs in the four-element cable code. In response to this, the six-space selector 210 opens contact 234 in a well-known manner. This releases relay 252 and the circuit of Figs. l, 2 and 3 are restored to their original condition.

-What is claimed is: Y

l. In a telegraph system, a source ci thirtytwo, tive-element, two-condition, permutation code, telegraph signal combinations connected to an electromechanical translator and means in said translator, said means comprising two individual multielement selectors each including a plurality of selectively operable relays, the relays of one oisaid selectors actuable by a given number cf the five elements of said code and the relays of the other actuable by the remaining elements, said means responsive to the reception ci any one of said signal combinations, for translating said received combinations into a corresponding particular one of thirty-two four-element, threecondition, permutation code telegraph signal combinations.

2. In a telegraph system, a source of five-element, two-condition, permutation code, telegraph signals connected to an electromechanical translating device, means in said device for translating said signals into four-element, three-condition signals said means comprising two individual multielement selectors each including a plurality of selectively operable relays, the relays of one of said selectors actuable by a given number of the ve elements of said code and the relays of the other actuable by the remaining elements, and means in said system for retranslating said signals into their original form.

3. A five-element, two condition, start-stop permutation code, Atelegraph signal transmitting station, a four-element, three-condition, cable code, telegraph signal transmitting station, a telegraph channel, automatic means for effectively connecting said channel through said four-element station to said rive-element station in tandem, a code conversion device connected to said channel for converting signal combinations in accordance with said five-element code into corresponding signal combinations in accordance with said four-element code, means connected to said channel to control the time consumed in the act of code conversion of each individual combination r and means in said control means for making each of said converted combinations of the same duration as'each of said four-element combinations.

4. In a telegraph system, a telegraph channel, a rst transmitting means connected to a first end of said channel and a iirst receiving means connected to a second end of said channel for transmitting and receiving telegraph signals in accordance with a first code over said channel, a secondtransmitting means connected to said iirst end of said channel and a second receiving means connected to said second end of said channel for transmitting and receiving telegraph signals in accordance with a second code, diilerent from said first code, over said channel and switching means responsive to particular signals transmitted over said channel for switching said 4second end of said channel from one to another of said receiving means, so as to connect the proper receiver to said channel to receive signals of a particular code.

5. In a telegraph system, in combination, a telegraph channel, a first and a second telegraph signal receiving device, a telegraph signal code retranslator intermediate said channel and said second device, means for directing telegraph communication signals over said channel to said ilrst receiving device at a first time, and means responsive to the transmission of switching signals over said channel for switching said channel from said first receiving device through said retransansa-coi Y lator to said second receiving-device? iat-:aiseeondftime.

w6.1i:v a telegraph system, a itelegraph lsignal code. translator` for. translating 'four-element, three-condition, `permutati'on'code signal cembinaticns into rive-element, Vtwo-condition, permutation code signal combinations and means Jin said translator vfor translating a subgroup of two signal elements of each of said fou'r-element-'s'ignal combinations into a subgrup 0f 'three/Signal elements 'of each of said five-elements'ignal come b'in'ations. l

` 7. In a telegraph system, al telegraph signal code translator for translating live-element, tivocondition, 'permutation code, signal combinationsin'to four-element, three-'condi'toi'r permutation code, signal combinations, a iirst means in fsaid translator fior translating three 'of 'the r'e eleinentsfcsaid yiii/e element signals into two c'f 'the elements ofsaid four-element signals and a sec'- 'ond 'means in said translator for translating :two of' the Velements oi' said tive-element signals into two o'f the elements of said four-element signals.

8.- In a telegraph system, 'a telegraph code translator i'or translating four-element, threecondition, permutation'code signals into fve-element, two-condition, permutation code signals, a r'stmeafns in said translator for translating two Vofthe elements of 'said four-'element signals into three of the elements of said five-element signals i [and a second means in said translator vfor translating two ofthe elementsrof 'said Vfour-element signalsinto two yof the elements Yof saidveelement signals.

9. In a telegraph system, a -'rst telegraph transmitter, means-in said transmitterfor generating-telegraph signals in accordance with a frs't code, a 'timing mechanism connected to ksaid transmitter, means connected' to said timing mechanism 'for controlling the dura-tion ofsigna'l elements in said code, a telegraph channel?, means vvfor impressing said timed signal elements on said channel, a second telegraph transmitter, means iii-said 's'econd'transmitte'r for' generating signals in' accordance with a vsecond code, d'iiierent "from said rrst code, `means for' impressing signals in accordance with saidsecond code 'on said channel and' lmeans -for tim-ing thedura-tion of vthe signal elements 'ofisaid second code 'with said timing mechanism so that they may be transmitted vvthrough facil-ities connected to said channel adaptable tothe duration ofj signal elements of said first code. y y

110. .In a telegraph system, a Vtelegraph *transmitter, means in said transmitteriortransmitting va tran-ici four signal elements to forma fourf elementstart-step permutation 4code signal-comwhich may be of any one of Vtwo conditions 'anda stop element, s, translator intermediatesaid transmitter 'andire'ceiven ya telegraph channel interconnecting said transmitter and vreceiver through translator andxmeans-fin said translator for translating said four-'element train into said sevemelernent train.

111. -Acode signal transmission system comprisingme'an's' .for producing a two-element; 'iive-un'it 00de, means Yfr(3fm-VeItI-ig.' thf'ee' Gh0`S`rlt1`Hit'S thereof 15D produce eight cb'i'libl'lt'dhs- 0f `lW'() unitslot a'fthre'e-eiament vicuii-unit code,- means fOrH-cenvertir'ig'twovother 'units' thereof to pro'- iour Umbmations of two: units of therthree element, #four-unit code, means vfor combining the eight combinations of two units p'ermutatively with the four combinations of the tWo other units to produce thirtyrtivo possible 'combinations and iiiean's-'for' i'itil'izinfvr codes of the thirty-two `coinbi-nat'ions ci the three-element, Vfour-unit code to control signal-ing apparatus. Y

1h21. AAccade signal transmission system comprising means for producing a two-element, n-unit code, mean-s 'for vconverting (11i-p) chosen units ther-coito produce (ft-pf2 combinations of two units of `a three-element km-'unit code, means for converting p other units ,thereof to produce a' (wherecc does nc-'texceed p2) combi-nations of two unitsof` the three-element m-unit code, means for combining the (n-fp)2 `combinations of two units permutatively with thezx combinations of the tivo other units to produce a given number ciipcss'ible combinations and means for utilizing the given number vof combinations of the threeelement, m-un'it code for signaling.

i3'. In a 'telegraph system, a five-'element permutation code telegraph signal transmitter, connected to a l`telegraph signal code translator, means in said 4translator for translating three vof said inve elements into two elements of a fourelement code and means in said translator for translating the two remaining elements` of said hveeleinentcode into the two remaining elen'rents of' saidffcur-element code. Y

` Y EDWARD F.'WATSON.

REFERENCES CITED fheiollowing references are of record in the nio-oi this patent:

' Umrans'rsrrns PATENTS Number

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