US1895112A - Printing telegraph exchange system - Google Patents

Printing telegraph exchange system Download PDF

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US1895112A
US1895112A US451693A US45169330A US1895112A US 1895112 A US1895112 A US 1895112A US 451693 A US451693 A US 451693A US 45169330 A US45169330 A US 45169330A US 1895112 A US1895112 A US 1895112A
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relay
station
circuit
contact
line
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US451693A
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Gilbert S Vernam
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International Communications Laboratories Inc
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International Communications Laboratories Inc
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Application filed by International Communications Laboratories Inc filed Critical International Communications Laboratories Inc
Priority to US451693A priority Critical patent/US1895112A/en
Priority to GB10585/31A priority patent/GB386614A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/02—Details
    • H04L12/04—Switchboards

Definitions

  • This invention relates to printing telegraph exchange systems and more particularly applies to manually operated printing vtelegraph exchange systems.
  • a toll switch board in the central oice one customers printer may be connected directly to another customers printer in the same city or in a different city.
  • the service provided by this toll switch board will correspond in general, to a toll telephone exchange service.
  • a feature of this invention is the reduction of line current to a fraction of its usual amperage when the line is idle.
  • a second feature of this invention is the operation of the toll line circuits full duplex for the purpose of controlling the lamp signals so that the calling and supervisory signals may operate independently in the two directions over the line, with the automatic conversion of the circuit to half duplex operation, when printing connections are made.
  • a further feature of this invention is a cord circuit for establishing vfull duplex through connections between two telegraph toll lines at an intermediate switching center with provision for the connection of an operators printer intq this cord circuit so that the operator at the intermediate station can communicate with both terminal stations.
  • a further feature of this invention is the use of monitoring keys in the cord circuits whereby the toll board operator can readlly cut her printer in or out of any of the cord circuits.
  • a feature closely associated with this one is the use of a splitting key in the toll board operators printer circuit permitting the toll board operator to comprinter with either cord of a
  • a further feature of this invention is the OF NEW YORK, N. Y., A CORPORATION 0F PRDITING TELE-GRAPH EXCHANGE SYSTEM 1930. Serial No. 451,693.
  • a further feature of this invention is an alternative arrangement whereby the customer may, by selective means predetermine where at the central station his call is to be answered.
  • a further feat-ure of this invention is the association of the signal lamps with the cord circuits rather than with the line circuits, and the arrangement whereby the lamps are lighted only when action is required on the part of the operator.
  • An additional feature of this invention is the provision of a motor control whereby the printer motors at the customers stations are started when the station line is connected to a printer or to a toll board cord at the central oiiice and the provision for stopping the motor from the central oiice or at the customers station.
  • Figure 1 shows in schematic form two groups of customers i' ⁇ of the form of the invention as illustrated i Figs. 2 to 5.
  • Fig. 2 shows in detail the circuit of a customers station, and the circuits of various parts of a central station viz. a concentration board, a concentration board operators printer set, a switching trunk and a central station printer set.
  • Fig. 3 shows in detail the left hand portion of station to toll line cord circuit yI and the circuit of station to station cord H.
  • Fig. 4 shows in detail the right hand portion of the station to toll line cord circuit I, the toll line to toll line cord circuit K and the left hand portion of the toll board operators printer set circuit L.
  • Fig. 5 shows in detail in circuit J the apparatus at one end of a toll line, similar apparatus being located at the distant endof the line at station M the direction of which is indicated but which is not shown; this gure also shows the right hand portion of toll board operators printer set circuit L.
  • Fig. 6 shows in detail the circuit of customers station() similar to circuit C of Fig. 2, and in circuit P a portion of a toll board and two concentration board si al panels at a central station showing their use with a selective call system.
  • Fig. 1 illustrates in outline, the proposed manual printer exchange system.
  • k While for purposes of illustration only ⁇ live customers statlons are here shown as associated with central station A there may be a lar e number of such stations and all the circuits have been so arranged that the whole system can be expanded with facility to handle an indefinite number of new customers stations as well as new central stations.
  • concentration board station connections may be readily increased and the number of concentration board and central stations operators printers can be increased to serve the additional local stations.
  • the number of station to station, station to toll line and toll line to toll line cords may vary in number according to the requirements of the traffi, only one of each type being shown, however, in this fi re.
  • circuits where e ansion may take place At the following points the ground connections ma be made through auxiliary signal circuits; ig. 2, circuit D, at 724; circuit F, at 710, 711 and y712; Fig. 3, circuit I, at 713; circuit H, at 714; Fig. 4 circuit I, at 715; circuit-K, at 716 and 717 Fig. 5, circuit J at 718; circuit L at 719; Fig. 6, circuit P at 720, 721, 722 and 723.
  • circuit F, Fig. 2 point 708, in clrcuit J, Fig. 5 and point 709 in circuit P, Fig.
  • circuit H at points 703 and 704 additional monitoring keys might be inserted for use with additional cord cir ⁇ cuits, likewise in Fig. 4, at points 705, 706 'sind 707. No attempt has vbeen made, however, to point out all the specific points at wlhich expansion of the system might take p ace.
  • any one customers station associated with one of the central stations may therebybe connected with any other customer station associated with that particular central station or with any other central station.
  • Fig. 1 customers stations 1 to 5, are shown connected by telegraph lines 6 to 10 to the concentration board jacks 11 to 15.
  • a concentration board operators printer 17 Connected to an additional jack 16 on the concentration board is a concentration board operators printer 17 by means of which the concentration board operator may communicate with the toll board operator.
  • 19 and 20 at the concentration board lead to tration board with the toll board for various types of service. They may connect any two of customers stations, 1 to 5 through the toll board by means of station to station cord 35.
  • the third cord 45 at the toll board is known as the toll line to toll line cord and may be connected to any two of the toll lines 39 to 41 through plugs 46 and 47.
  • monitoring keys 48, 49 and 50 are respectively inserted. By means of these monitoring keys the toll board operators printer 51 may be connected to any one of the three cord circuits.
  • Central station B together with its customers stations and lines and toll lines, is a duplicate of vcentral station A and its auxiliary rlines and has therefore not been specificall described.
  • central station A las an intermediate station for connecting two other central stations, connections will be made over two of the toll lines 39, 40 and 41 by -means of a toll station to toll station cord 45 the circuit thus passing through only the toll board ofthe intermediate station.
  • polar rela 101 is connected in series with customers telegraph line 102 joining the 'customers station C with concentration board D at the central station.
  • This relay 101 has two windings, connected in series, one of low resistance 103 and one of high resistance 104, and is equipped with a biasing spring 105 which tends to move the relay armature 106 against contact 107.
  • Relay 101l will be released and will close contact 107 on the application of a positive potential to line 102 at the central station. In the normal or idle condition of the customers station circuit, l
  • relay 101 will be operated but marginal relay 113 will not be affected by this strength of current.
  • a cord plug In the case of a call, either from a central station circuit of this figure (21, 22 or 23 of Fig. 1) or from the toll board (see Fig.'1), a cord plug will be inserted in one of the line jacks 123 of the concentration board with the result that a positive potential will be applied to customers station line 102. The method of applying this positive potential tothe cord circuits will be described later.
  • control relay 128 which closes its contacts 139 and 138 there- .by respectively, putting into operation printer motor 140, and short-circuiting high resistance Winding-104 of relay 101.
  • the line current now increases to its usual working ⁇ value of about 60 milliamperes.
  • Resistance 116 in customers line 102 is included in the circuit to regulate the current to this value and to compensate for variations in the resistances of the line wires to different' stations.
  • printer signals may be sent from the sending contacts of customers station'transmitter 1'19 or from those of a central oiiice or distant printer, and these signals will operate the respective printers without operating relay 101 since spring 10@ gives the relay a positive bias.
  • the calling key 141 (prrinter 122 in central station printer that the lever will lock in the calling'position or in the normal position but when operated to the releasing side (for purposes to be described later) the key is non-locking and will restore itself to the normal'position when released by the operator.
  • the increased line current will operate marginal relay 113 at concentration board D, which relay, will in turn operate relay 143 of the concentration board circuit which locks itself through a circuit traced from ground 144 through contact 145, jack contact 146, conductor 147, current source 109 and ground 108. Under these conditions current will be applied to toll lamp 148 at concentration board D over a circuit which may be traced from ground 149, contact 150 of relay 143, conductor A151, front contact 152 of relay 113, conductor 153, conductor 154, current supply 109 and ground 108, lighting the lamp and indicating that a connection with the toll board is d esired.
  • relays 113 and 143 will operateas described and then relay 113 will release, with the result that the message lamp 155 will be lighted, indicatingr that the customer wishes a connection with a central station printer to record an outgoing telegram or cablegram.
  • relay 101 of customers station C will not be released until a positive current is connected through the concentration board to customers line 102, as previously described.
  • the insertion of a cord plug into the jack 123 at concentration board D will obviously release relays 113 and 143l by ⁇ breaking the operating circuits of these relays at contacts 115 and 146 respectively extinguishing whichever lamp is lighted.
  • Relay 131 is thus operated and locks itself through its front contact 159 thus breaking the operating circuit of control relay 128 at contact 130 and releasing said control relay which in turn -stops printer motor 140 by breaking contact 139 and connects the high resistance Winding 104 of relay 101 into the "line circuit by breaking contact 138.
  • the resultant reduction in the current in customers line 102 acts to light supervisory signals in the various cord circuits at the toll board as will be described later.
  • Central station prt-'Itter set crm't As was indicated in Fig. 1 the central station apparatus and circuits ⁇ consist generally of concentration board D, concentration board operators printer set E, switching trunk F, central station printer circuits G, station to station cord circuits H, station to toll line circuits I, toll line circuit J, toll line to toll line ⁇ cord circuit K and toll board operators printer set circuit L.
  • Circuit G of Fig. 2 illustrates the circuit of the printer set at the central telegraph office used for sending and receiving telegrams and cablegrams. In the idle condition, all of the relays in this circuit are released asV illustrated .and the printer motor 160 is stopped.
  • the plug 161 which is located at the central station concentration board, is in serted into jack 123, by the concentration board operator thus connecting the central station printer set circuit G with customers station C through line 102, the control relay 162 willbe operated to start motor 160, light the guard lamp 163, and to supply current for the local circuits of the printer as well as to connect a positive current from current source 164 to the customers station line 102.
  • the circuit for operating the control relay may be traced from ground 108 .at concentration board D through current' source 109, protective resistance 165, conductor 147, jack contact 166, sleeve of jack 123, sleeve contact of plug 161, conductor 169, junction point 199, conductor 170, key 171,
  • conductor 172 back contact 173 of sleeve relay 174, conductor 175, conductor 176, and
  • relay 162 closes Contact 168 which connects current lsource 164 through contact 168 to junction 178 from which current flows through resistance 179 to guard lamp 163 and thus to 102 to customers station C as above indi' cated Where motor 140 is started.
  • the stations now are ready for the transmission of when it is inserted in the jack is so low that it is impossible for the operator to receive a shock from the circuit, except possibly from an inductive discharge from the winding of control relay 162 or the kwinding of sleeve relay 174 when the cord plug 161 is pulled down. This could be avoided, if necessary, lb connecting a resistance from the sleeve of p ug 161 to the ground.
  • the same general method of preventing shocks is used for all the jacks and plugs on the toll board.
  • the central station printer operator momentarily operates release key 171.
  • This breaks a connection through conductor 172, contact 173, and armature 175, which short-circuits the winding of sleeve relay 174, thus permitting relay 17 4 to operate in series with the control relay 162 and on being energized, sleeve relay 174 itself opens the short-circuit at back contact 173, so that it will not release when the contacts of release key 171 are again closed.
  • It also shortcircuits the winding of control relay 162 b grounding itself through its front contact 18 and ground 188, thus releasing control relay 162, which opens contact 168 thus cutting olf the current from guard lamp 163 and conductor 181 and stopping the printer motor 160.
  • Sleeve relay 174 also applies a negative current from source 189 through the winding of the marginal recall relay 190 to the station line circuit by means of. conductors 191, front contact 192 of sleeve relay 174 and conductor 185, and vtip of plug 161. This current o erates relay 101 at the customers station to pull up armature 106 which opens a circuit to sto printer motor 140 as previously described.
  • Sleeve relay 17 4 also passes a negative current from current source 189 through resistance 193, conductor 194, contact 195, conductor 196, and disconnect lamp 197 Ato ground 198, which circuit lights disconnect lamp 197 located at the concentration board as a signal to the concentration board operator to pull down cord plug'161.
  • call key 141 at customers station C may be operated to close contacts 142 to increase the negative 6 milliamperes currentto a negative current of approximately milliamperes as previously. described.
  • the recall relay 190 of printer set G which is a marginal relay operable on a current of 60 milliamperes but not on a current of 6 ,milliamperes, and which is connected through front Contact 192 of sleeve relay 174 to the customers line, will operate and short-circuit sleeve relay 174 through a circuit traced from junction 199, ⁇ through conductor 170release key 171, conductor 172, contact 200, armature 201, conductor 202, Winding of control relay 162 and -ound 177.
  • Sleeve relay 174 having been re eased will disconnect the circuit operating recalnlwrelay 190 through contact 192.
  • Recall relay 190 is shunted by resistance 203 to make it slightly slow to release thereby preventing it from releasing until sleeve relay 17 4 has b een completely released.' The release of sleeverelay 174 also removes the short-circuit from control relay 162 which thereupon operates,
  • the switching trunk circuit is shown at F of Fig. 2, (see also switching trunks 27, 28 and 29 in Fig. 1). This circuit serves to extend lthe connections inl either direction ybetween the concentration board and the toll board. If the toll board has more than one ying theguard lamp 163 and passing a current position, the circuits can be multipled at the toll board as indicated in the drawings, (204 .of circuit fF, Fig. 2). If there are several concentration boards, each board will have its ⁇ own group of trunk lines to the toll board,
  • Marginal relay 215 is thereby operated, closing contact 219 and thus closing circuit from ground 220, through positive current source 221, resist- Aance 222, contact 223, conductor 224, contact 219, conductor 225, call lamps 167 and 226 to I ounds 186 and 227 respectively, thereby are located at the toll board.
  • Relay 206 in operating also short-circuits resistance 228, thus preparing a circuit for later operating the guard lamp 229 located at the concentration board.
  • the detailsof these -cord circuits will be explained later.
  • the i, insertion of oneof these plugs places ground 40 on kthe sleeve of jack 210 through sleeve of plug 231, conductor 233, winding of relay 451, conductor 452, winding of relay 234 and 'ground 235.
  • the toll board operator inserts a cord plug 230 or 231'(Fig.'3) into an idle switching trunkl jack such as 210. This closes contact 236 and thus places the ground associated with the sleeve 'of plugs 230 or 231 on conductor 237y and passes it through'resista-nce 228 (relay 206 being unoperated) over conductor 239 and through the windings of busy relay 240, through resistance. 241, source of potential 221 to ground 220. Resistance-228 in this case, so
  • the concentration board operator will then insert the switchin trunk plug 205 into jack 123 of the callecustomers station line, this will apply a negative current from current source 109 at concentration board D to the sleeve of jack 123 which in turn will pass the current throu h the sleeve of plug 205 to the winding o sleeve relay 206 of switching trunk F, thus operating relay 206 which opens contact 254 and thus extinguishes guard lamp 229.
  • Relay 206 by closing contact- 238 shunts resistance 228, placing suicient additional current from source 221, on the coils of marginal relay 234 (Fig. 3) of cord I or 251 (Fig. 3) of'cord H, to operate it, thus applying a positive current from source 437 (Fig. 4) or sourceV 'tomers station C where it will start the y into the line again at jack 210.
  • the toll board operator pulls down the cord plug fromswitching trunk jack 210 which breaks contact 236, releasing busy relay 240 and closingcontact209 of Jack210 thus re-establishing the circuit through the winding of marginal relay 215 to the negative current source 217. This operates relay 101 and releases relay 128 at the customers station, and as the call.
  • Relay 215 may operate momentarily immediately after the removal of the plug, but it will release when the line current is reduced. As relay 240 is released, and sleeve relay 206. remains operated, the circuit from current source to guard lamp 229 is closed andthe lamp will light.Y Contact 245 beingopened on the release of relay 240 the busy lamps 242 and 243 will be extinguished. Under these conditions, the concentration board operator should pull down the switching trunk cord plug 205, restoring the circuit to normal.
  • Relays-'206 and 240 of switching trunk F (Fig. 2) will, therefore, be energized as well as the control relays 128 at the customers station C (Fig. 2) and the sleeve relays 251 and 259 of the station to stationcordcircuit H will also be operated.
  • the polar repeaing relays 257 and 258 will be energized in a direction to hold their respective, armav tures 259 and 260 against marking vcontacts 261 and 262 respectively.
  • the two left hand windings 263 and 264 of relay 257 and windings 265 and 266 of relay-258 are differentially connected, windings 263 and 265 being connected to ground through the concentration board and the station line, which circuits may be traced, for winding 263, through conductor 808 through front contact 267 to the tip of plug 268 and so through a switching trunk F (Fig. 2), and concentration board D to customers line 102; for winding 265 through conductor 269,
  • Windings 264 and 266 are carried to ground through artificial lines 273 and 274 consisting respectively of resistance 275 andV inductanc'e 276 and resistance 277 and inductance 278. From junction point 279 where the artificial lines unite a circuit may be traced over conductor 280 to junction point 282 and through conductor 283 and contact 284 of sleeve relay 259 t0 ground 285.
  • each of these relays will respond to signals sent fromthe station to which its line winding is connected.
  • each relay When so operated, each relay will repeat these signalsthrough the .windings of the other relay into the other station line, thus, if' the line to which winding 263 of relay 257 is connectedis closed at the called customers station C, (Fig. 2) a current will be sent through a circuit as follows: from ground 290, of station to station cord H through source'of positive potential 291, conductor 292, junction point 293, resistance 294, armature 260,1narking contact 262,A conductor 296, back contact 297 of cut relay 298, conductor 299 to junction point 288 and thus through winding 263 of relayv 257 and through conductor 808, contact 267 of relay 259 to the tip of plug.2 68 and thus through a switching trunk F (Fig.
  • Relay 257 (Fig. 3) will then close its marking contact 261 and cause a current to pass from source of positive potential 291, associated with ground 290, through conductor 292, junction point 300, resistance 301, conductor 302, armature 259, marking contact 261 of relay 257, back contact 303 of cut relay 298, conductor304 to junction point 289 and thus through winding 265 of relay 258, conductor 269, contact 270 of monitoring key 306, conductor 271, contact 272 of relay 251, to the tip of plug 230 and thus over a second switching trunk F (Fig. 2), through concentration board D to a second customers line 102 to the calling customers station-C where the printer magnet 118 will be operated and finally to ground 121.
  • a second switching trunk F (Fig. 2), through concentration board D to a second customers line 102 to the calling customers station-C where the printer magnet 118 will be operated and finally to ground 121.
  • Winding 305 of relay 257 and winding 295 of relay 258 havevlessturns than the other two windings of these relays and the currents through them have comparatively small magnetic effects in a direction tending to aid the line windings 263 and 265, respectively, in'
  • relay 257 for instance, repeats signals through relay 258, the latter relay will not respond to these signals as its armature 260 is held against its marking contact 262 by winding 295 when windings 265 and 266 are open at relay 257, that is to say, when spacing contact 2,86 of relay 257 is closed, armature 260 is held against marking contact 262 by winding 295 and. when armature 259 reverses and contact 261 is closed armature 260 is still held against contact 262, but this time by winding 265.
  • This circuit can be traced as follows: from junction point 308 (Fig.v 3) of monitoring key 306 through contact 309, conductor 310, contact 311 of monitoring key 312, (also through contacts similar to 311 of monitoring keys for other cord circuits indicated by dotted lines 704 and 705) conductor 313, contact 314 of split key 315 (Fig.
  • conductor 316 conductor 316, winding 317 of polar relay 318, conductor 319, contact 320 of monitoring key 321, (also through contacts similar to 320 of monitoring keys for other cord circuits as indicated by dotted line 706) conductor 322, contact 323 of monitoring key 321, conductor 324, key 325, toll i board operators transmitter 307, conductor 326, contact 327, conductor 328, ⁇ - contact 329 of monitoring key 312, conductor 330, contact 331, to conductor 271 in station to station cord circuit H.
  • the contact springs of the monitoring key 306 are so arranged and adjusted that the key can be operated or re ⁇ stored to cut the toll board operators printer unit (key 325, transmitting contacts 307, line relay 318 and printing magnet 578) inor out of the circuit without momentarily interrupting the station line circuit. Also if two or more monitoring keys are operatedl together in error, this will not interfere with the communication vbetween the customers,
  • the operators printer will be conne/ctedv to the cord circuit whose monitoringkey is nearest to the operators set in the circuit, viz., if the monitoring keys 306-and 312 are both operated at the same time, the operators.
  • monitoring key 312 a monitoring key associated with a toll line to toll line cord K (Fig. 4) should notbe operated at the same time as that of one of the other types of cords as thi/s would permit signals to be repeated from one cord circuit to another. l
  • the split key 315 of the toll board operators printer set circuit L may be used if the operator wishes to communicate with one customers station C andat the same time cut off the other customers station C. For example, if this key is operated in a direction to open the contact 314 and close contacts 332, 333 and 334, the operators printer will be connected through cord plug 230 of station to station cord H,.sincethe opening of contact 314 and the closing of Contact 332 cutsk off 'the return circuit to relay 258 (Fig. 3)
  • relay 342 which opens contact 347 thus preventing relay 348 from operating.
  • the operator may now communicate directly with the station connected through cord plug 230 (Fig. 3) and these signals will not be repeated through the station connected through cord plug 268 (Fig. 3).
  • the station connected through the latter plug may, however, recall the operator by holding recall key 120 at customers station C (Fig. 2) operated for a few seconds. This will open the line and release supervis-x ory relay 342 (Fig. closing contact 347.
  • relay 348 which is a slow to operate relay will operate over a circuit traced from ground 349 (Fig. 4) of the split key circuit, contact 334, conductor 350, contact 347 ig.
  • relay 348 closes the operating circuit of guard lamp 355 at Contact 356 thereby lighting the lamp and relay 348 locks itself at contact 357 to hold the guard lamp lighted until split key 315 is restored to normal.
  • relay 240 of the switching trunk which will extinguish call lamps 167 and 226 and lightthe busy lamps 242 and 243 as previously described. It will also operate sleeve relay 251 (Fig. 3) of station to station cord circuit H. This relay current to the line and artificial line windings of the other relay.
  • the circuit of the line winding of relay 258 extends to calling customers station C (Fig. 2) as previously traced ⁇ where by reason of the positive current carried over said line from current source 291 (Fig. 3) of station to station cord circuit H, relay 101 (Fig. 2) is released and printer motor 14() started as previously described.:
  • the circuit of the line winding of relay 257 (Fig. 3) extends through baclli contact 365 of sleeve relay259 and through resistance 366 which is equivalent to a station line.
  • cord plug 268 will be inserted into jack 210 (Fig. 2) of an idle switching trunk F. As previously explained in connection with the operation of sleeve vrelay 251, this will extend a ground connection to the relay 240 of switching trunk F throughA the sleeve of cord plug 268 and contact 236 of jack 2,10 but as the circuit has not yet been extended to a called customers station C, relay ⁇ 206 of the switching trunk. circuit F has not been operated and consequently .c
  • Vof station to station cord circuit H operates releasekey 141 first, relay 258 (Fi 3) of station to station cord circuit H, wil release but as this opens a circuit at contact 262, to both windings 263 and 264 of relay 257, relay 257 cannot release at this time by reason of the eiiect of winding 305 even though the called station, connected through cord plug 268, also operates its release key 141.
  • Relay 258 thereupon closes a circuit from its spacing contact 287 as follows: from current source 291 associated with .ground 290 through conductor 292, junction point 293, resistance 294, armature 260, contact 287, conductor 367, resistance 368, winding of relay 363, junction point 370, conductor 371, contact 37'2 of monitoring key 306, conductor 373, conductor 374 through contact 375 of relay 251 to ground 281.
  • Relay 363 is a slow act-ing relay which will not operate on short impulses due to printer signals but will operate when armature 260 of relay 258 remains against its spacing contact 287 for a longer interval.
  • Relay 363 being operated, closes -its contact 376 and thereby places ground 377 in the circuit of supervisory lamp 378 associated with cord plug 230 thus applying current from source 291 to the lamp and lighting it. Relay 363 also closes contact 379, which places ground 380 on the ffgcut relay 298. The cut relay operates, and
  • Relay 363 in effect, therefore, cuts the repeater so that a signal sent into one side of the repeater will now have no effect on the line circuit of the other side of the repeater. If the release key 141 (Fig. 2) at the called customers station C, connected to cord plug 268 (Fig. 3) of station to station cord H, has been operated by this time, relay 257 will now release by reason of the insertion of high resistance winding '104 (Fig. 2) into the circuit at the called customers station C and after an intervaly relay 3.62 (Fig.
  • the recall key 120 (Fig. 2) at customer-s station C may be opened for a period of time suliicient to allow slow operating relay I362 or 363 (Fig. 3) respectively to operate the corresponding supervisory lamp 384 or 37 8, the supervisory lamp, under these conditions, might be flashed by operating and releasing the' recall key slowly several times in succession.
  • a telegraph toll line circuit is shown at J of Figure 5 (see also J in Fig. 1).
  • two polar relays are used, so connected as to form a difcapable of transmitting signals in both directions could be used.
  • a metallic two wire line equippedl for duplex operation might be used, or two wires, each arranged to 'send signals in one direction.
  • a full duplex carrier telegraph channel might be used or even a two-way radio telegraph channel. It
  • Pole changer 385 is connected through jack contact 386 of jack 387.
  • Pole changer 385 is also connected by a circuit traceable through contact 386, conductor 388,' (which also extends through contacts similar to 386 of any intermediate jacks which may be placed in the circuit at point indicated by broken line 7 08'-it should also be noted that additional lamps may also be inserted at this point) contact 389 of jack 390, conductor 391, resistance 392, winding of busy relay 393 to ground 394.
  • Busy relay 393 is a sensitive relay that will operate on a small current.
  • the line relay 406 is not affected by this current but as the pole changer at an identical station M (not shown), at the distant end of the line, is also against Vits spacing contact, the armature of the line relay at station M corresponding to relay 406 at station J, viz. 406M will also be against its open or spacing contact, and the receiving leg, or in other words, thel conductor 409M leading to the tip of jack 387M will be open.
  • cord plug 412 (Fig. 4) is inserted in toll line jack 387, a current from source 414 will be carried over conductor 410 to sleeve of cord plug 412, in other words, the sending leg of the duplex set will be connected through contact 411 to the sleeve of jack 387, and if the sleeve of plug 412 is connected through a suitable resistance to ground, this ground will be placed o-n winding 398 of pole changer 385 through contact 411 of jack 387 and conductor 410.
  • ground 478 replaces' ground 394 whichis' associated with the'busy relay 393 and that resistance 699. associated' with ground 478, is a. lower resistance than resistance 392 associated .with ground 394. Consequently, with the placing. of ground 478 on winding 398, more current iiows through this winding than through winding 397, and armature 399 is therefore operated against its negative or marking contact 416.
  • the circuit for operating relay 417M maybe traced as follows: ground 420M, source of potential 421M,fresistance 422M. contact 423M, conl'ductor 409M, contact 424M of jack 387M, conductor 425M, contact 426M of jack- 390M, conductor 427M, winding of relay 417M through resistance 428M to ground 429M.
  • cord plug 231 (Fig. 3) of station to toll line cord I will ulti'- mately be inserted into switching trunk jack 210 Fig. 2).
  • the insertion of plug 231 into jack 210 closes contact 236 and, as previously described, places a positive potentialV on the sleeve of plug 231 throughv current source v 221 of switching trunk circuit F. This current is passed from the sleeve ofcord plug 231vover conductor 233 (Fig.
  • Relay 451 will also be operated to close contact 453 which operates a circuit from ground 454 through positive potential 455, resistance 456, contact 453, conductor 457,'contact 458 and so through supervisory lamp 459 to ground 460.
  • the supervisory lanip459 will be lighted immediately on connections being made between cord circuit I and switching trunk F.
  • Relay 234, by closing contact 443 connects a positivel current from current source 437 (Fig. 4) to the customers station line 102 (Fig.
  • Cord plug 412 (Fig. 4) is now inserted into the jack 387 (Fig. 5) of an idle toll line to the desired distant city.
  • Repeating rela-y 464 (Fig. 4) in cord circuit I operates like relays 257 and 258 of station to station cord circuit H. which was previously described and therefore its method of operation need not be described here in detail.
  • lVinding 465 of relay 46 4 correspondsto windings 263 and 265 of relays 257 and 258 respectively
  • winding 466 of relay 464 corresponds to windings 264 and 266 of relays 257 and 258 respectively
  • winding 470 of relay 464 corresponds to windings 305 and 295 of relays 257 and 258 respectively, and the corresponding windings have approximately the same resistances. It should be noted, however, that as line relay 406 of the toll line is released when plug 412 isfirst inserted in jack 387,
  • the receiving leg 409 (Fig. 5) of the duplex set is open and there will be no current through the two windings 465 and 466 ot relay 464 (Fig. 4) but the relay will be held operated by a current from source 437 passed over conductor 467, through resistance 468, conductor 469, through winding 470 of relay 464 to ground 471.
  • the contact 472 of relay 464 being closed, a circuit may be traced from ground 415 (Fig.
  • Relay 481M also operates over a circuit traced from junc-v tion point 482M through winding 466M of relay 464M, resistance 483M, inductance coil 484M, winding of relay 481M to ground 485M.
  • the operation of relay 481M will close contact 486M to place ground on slow release relay 487M over a current operating from ground 485M to contact 486M, through conductor 488M, winding ot relay 487M, conductor 489M, resistance 490M, conductor 467 M and through source of potential 437 M to ground 438M.
  • Relay 487M willt-hen operate to break Contact 47 5M, removing supervisory lamp 477M from the sleeve circuit of jack 387M (Fig. 5) and replacing the ground .478M (Fig. 4) associated with the supervisory lamp 477M by ground 491M through resistance 492M at contact 493M.
  • the supervisory lamp 477M is thereby extinguished, and pole changer'385M operates.
  • pole changer 385M (Fig. 5) sends a marking signal back over line 407 to operate the line relay 406. This closes the receiving leg 409 connecting positive current fromv current source 421, through Contact 423, over receiving leg 409, through jack 387, to tip of plug 412 (Fig. 4) and so to windings 465 and 466 of relay 464.
  • the relays 481 and 487 will be operated as previously explained in connection with the operation of station M, the latter relay extinguishing supervisory lamp 477.
  • Relay 487 will also extend the receiving leg circuit 409 from winding-465 of relay 464, over conductor 702 through junction point 730, conductor 731, contact point 496, conductor 442 and contact point 443 (Fig. 3) and so through monitoring key 312 to the line circuit extending to the calling customers station C.
  • the outward operator may operate split key 315 (Fig. 4) in a di? rection to operate the right-hand springs, closing contacts 358, 359 and 360 and thus connecting a positive current through relay 342 (Fig. 5) to the calling customers station line 102 and connecting station M through cord plug 412 and the operators printer 307 to ground 346 (Fig. 5) as previously described.
  • split key 315 Fig. 4
  • the right-hand springs closing contacts 358, 359 and 360
  • the o erator at station M will connect plug 231KI Fig. 3) to an idle switching jack 210M Fig. 2) and establish a connection toA the called subscribers station C in the same manner as previously described for local calls.
  • cord plug 231M is inserted into jack 210M, sleeve relay 234M does not operate until switching trunk F at the distant station is plugged up at the concentration board. at which time it does operate to extend the toll line circuit through to the called subscribers station C starting the station motor in the usual manner, as previously described.
  • the customers stations may now communicate with each other by printer.
  • the outgoing printer signals through each station operating repeating relay 464 (Fig.4) of thel cord circuit I, which will in turn open and close the sending leg circuit at contact 472 to operate pole changer 385.
  • Incoming signals from the toll line 407 (Fig. 5) will operate line relay 406 which will repeat these signals overl the receiving leg circuity 409 directly through the windings 465 and 466 of relay 464 (Fig. 4) to the station line 102 (Fig.
  • relay 464 is in effect a half set repeater and has the effect of converting ,y the full duplex circuit into a half duplex circuit.
  • the operators at the two customers ⁇ stations C may both transmit and receive but both cannot transmit at the same time.
  • the toll board Ioperators at the two central stations should cut out of the circuitD by restoring their monitoring keys 312 as soon as communication isy satisfactorily established.
  • the outgoingsignals will operate marginal relay 449 (Fig. 3) as' previously described, and the incoming signals from the distant station vwill operate relay 481 (Fig. 4) as well as relay 449.
  • Relays 449 and 481 will send impulses through the windings of relay 487 ever, and will not release on printer signals. If the operator at either of the customer s stations should wish to recall his toll board operator, he ⁇ may do so by slowly opening and closing the contacts of the recall Vkey 120 (Fig. 2) at customers station C.- This will release marginal relay 449 (Fig. 3) for a suflicient yinterval to allow relay 463 to release and light the supervisory lamp 459, as previously described. vIt will. also release relays 481M (Fig. 4) and 449M at the distant end of the line. This will permit relay 487M to release, closing contact 475M and thus ligblting supervisory lamp 477M. Re-
  • Relay 463M should prefera ly be adjusted to be' Such a local signal may be answered by the o ⁇ erator by means of monitoring key 312 ig. 3) and if trouble is being experienced,
  • ⁇ split key 315 (Fig. 4) may .be o erated, if
  • relay 464 will be held operated by winding 470, as previously described. Relays 481 and.487 will release, however, to light supervisory lamp 477, as previously described.
  • the supervisory lamp 459 (Flg. 3) at one station is now lighted as well as supervisory lamp 477 (Fig. 4) at the second station.
  • relay 449 (Fig. 3) at that point will release and, after an interval, relay 463 w1ll release and light supervisory lamp 459, as previously described. This will have no effeet on the toll line circuit, however, as re lay 464 (Fig. 4) is held operated as prev1- ously described.
  • both supervisory lamps will be lighted at one toll board and supervisory lamp 459 (Fig. 3) alone lighted at the other board. Both operators should then.'pull down their cords, restoring the circuits to normal.
  • ToZZ Zine to toll Zine coml For establishing through connections between two central stations the toll line to toll line or through cord shown as circuit K (Fig. 4) should be used. The operator will normally answer such calls with the station to toll line cord I, previously described, and on finding that a.v through connection to a distant city is desired ascertains the statlon wanted and then substitutes a through cord Tt will be understoodthat the twocord plugs 494 and 495 of this circuit are, whenthe cordis connected, plugged into jacks 387 (Fig. 5) of two separate toll line circuits J. In this cordcircuit, the tip of cord plug ⁇ 494 (Fig.
  • the relays in the cord circuit K are not used for repeating signals from one toll line to the other but serve to enable the local operator to connecther printer into the circuit current when the cord is not in use and to extinguish the supervisory lamps.
  • Relays 496 and 497 serve this purpose. These relays each have two windings, one of low resistance 498 and 49.9 and one of high resistance 500 and 501, and are capable of operating on a low current.
  • the same type of relay as relay 101 (Fig. 2) in the customers stations circuit C may bepreferably used for this purpose, but it is not necessary to use a polar relay if a sufficiently sensitive neutral relay is available.
  • Relay 496 will be operated but since the high'resistance winding 500 ⁇ of this .relay and resistance 520 in series with it, hold the current to about of relay 496 contact 538 is closed and ground 521 is resultingly ⁇ placed on a circuit traced as follows: from contact,538 to junction 801, conductor 550, winding 549 of relay 522conl ductor 548, winding 547 of relay 523, conductor 546, winding 545of relay 508, 'conductor 544, winding 543 of relay 512, conductor 542,
  • plug 495 will be plugged into an idle jack 387 (Fig. 5) of an idle toll line connected to the distant called station before slow operating relays 559 (Fig. 4) and 560 (since the operator has ascertained the name or number of the called station before plugging up either plug or cord K) ⁇ can operate, in which case the'circuit from the tip of plug 494 to the sleeve of plug 495 will be closed and the circuit from 3 milliamperes relays 385 (Fig. 5) and 512 (Fig. 4) will not operate. AOn the operation

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)
  • Monitoring And Testing Of Exchanges (AREA)
US451693A 1930-05-12 1930-05-12 Printing telegraph exchange system Expired - Lifetime US1895112A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US451693A US1895112A (en) 1930-05-12 1930-05-12 Printing telegraph exchange system
GB10585/31A GB386614A (en) 1930-05-12 1931-04-10 Printing telegraph exchange systems
FR717377D FR717377A (fr) 1930-05-12 1931-05-12 Installation d'échange de télégrammes imprimés

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US451693A US1895112A (en) 1930-05-12 1930-05-12 Printing telegraph exchange system

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US1895112A true US1895112A (en) 1933-01-24

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2472885A (en) * 1940-07-19 1949-06-14 Barber Colman Co Automatic multiple stage telegraph system
US2505722A (en) * 1947-06-04 1950-04-25 Martha W C Potts Synchronizing unit
US3076056A (en) * 1958-11-17 1963-01-29 Automatic Elect Lab Telegraph signal arrangement for a telephone system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2472885A (en) * 1940-07-19 1949-06-14 Barber Colman Co Automatic multiple stage telegraph system
US2505722A (en) * 1947-06-04 1950-04-25 Martha W C Potts Synchronizing unit
US3076056A (en) * 1958-11-17 1963-01-29 Automatic Elect Lab Telegraph signal arrangement for a telephone system

Also Published As

Publication number Publication date
GB386614A (en) 1933-01-19
FR717377A (fr) 1932-01-07

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