US2345851A - Teletypewriter switching system pay station - Google Patents

Description

April 4, 1944. w. Y. LANG Erm.

TELETYPEWRITER SWITCHING SYSTEM PAY STATION Filed May 9, 1941 4 Sheets-Sheet 1 w K LANG NVENTORS R J. s/NGER BV l ATTORNEY APH! 4, 1944 w. Y. LANG ETAL y 2,345,851

TELETYPEWRITER SWITCHING SYSTEM PAY STATION i Filed May 9, 1941 4 Sheets-Sheet 2 ro :acceso/Ns KE r POLA RIZED POLAR! TELErrPEwn/rtn copo c/Rcu/T IHI' IIHIl I, N

A 7` TOR/VEV April 4, 1944.

w. Y. LANG V1=:r AL

TELETYPEWRITER SWITCHING SYSTEM PAY STATIO 4 sheets-sheet 3 Filed may 9. 1941 lud W K LANG FIJ. SNGE BV y ATTORNEY April 4, 1944.

w. Y; LANGET AL TELETYPEWRITER SWVETCHING SYSTEM PAY STATION Filed May 9, 1941 .4 SheetS-Sheet 4 n? e LANG NVENTORS.

BV i

, A T TOPNE V Patented Apr. 4, 1944 TELETYPEWRITER SWITCHIN G SYSTEM PAY STATION Wilmarth Y. Lang, Towaco, N. J., and Fred J. Singer, Rockville Centre, N. Y., assignors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application May 9, 1941, Serial No. 392,682

Claims. i

writer motor cannot be started at the station until this has been done. i, A further feature of this invention is an arrangement wherein the station teletypewriter may be started either by the subscriber at a station where a call is being initiated or it may be started from the central office and in which their' teletypewriter may be stopped at either of these two points or from a distant station in the connection. The station motor is stopped on the reception of a teletypewriter code signal correspending to a particular character.`

A further feature is an arrangement wherein on incoming calls to the teletypewriter pay station a common type ringer at the pay station may be controlled at the central station to'give anI audible signal to call the pay station subscriber.

A further feature of this invention is an arrangement wherein the pay station loop circuit, which is normally open at the pay station, may be closed in response to a continuous ringing signal of longer than normal duration transmitted from the central station.

A further feature is an arrangement wherein the central station operator may either return coins which have been deposited in the coin collection device at the pay station or collect said coins and these operations may be performed either while the station motor is operating or while the station motor is stopped.

A further feature is an arrangement wherein the central station operator may prevent the subscriber from typing until additional coins have `been deposited at the pay station.

typed record oftheamount of money deposited in the pay station coin box is provided both at the pay station and at the central olice as each coin is deposited.

A further feature is an arrangement wherein when the station is idle all power is disconnected from the pay station apparatus.

These and other features will become apparent from the following description when read with reference to the associated drawings in which:

Fig. 1 shows a teletypewriter pay station circuit, located at the left ofthe gure and interconnected by means of a pair of conductors to the teletypewriter pay station line terminating circuit at the central teletypewriter switching station, indicated at the right of the ligure;

Fig. 2 shows a teletypewriter cord circuit for use in flexibly interconnecting the circuit per Fig. 1 with other circuits;

Fig. 3 is an operators position circuit which may be connected to a particular cord, such as Fig. 2, when an operator at the central station desires to communicate either with a subscriber at the teletypewriter pay station per Fig. 1 or over some other circuit to which the cord per Fig. 2 may be connected;

Fig. 4 is electrically the same as Fig. 1, but is inverted, so as to better illustrate a called line, as .an aid in understanding how Fig. 1 and Fig. 4

cooperate with the cord circuit of Fig. 2; and

Fig. 5 is a diagram representing the position in which Figs. 1, 2, 3 and 4 should be arranged to conform to the description herein.

The manner in which the circuits function will now be described in detail.

Pay station subscriber initiates a call Please refer to Fig. l.

In order to initiate a call, the subscriber at the teletypewriter pay station in Fig. l deposits a coin in the coin collection device at the teletypewriter pay station. The coin collection device is represented by the rectangle l. We lare not herein concerned and will not here describe the mechanism of the coin collection device except for its electrical apparatus 4and connections. Coin collection devices of the same general type as that indicated by rectangleA 100 are described in Patent 1,043,219 to O. F. Forsberg, November 5, 1912, and Patent 1,137,399 to C. L. j Goodrum, April 27, 1915. It is to be understood that in the coin collection device a number of` coin slots are provided. The mechanism -is arranged in a wellknown manner so that. the different coins will follow different paths-to'operate different contacts. Thus a five-cent piece which is deposited will close contacts |6|; a ten-cent piece will close contacts |02; a twenty-ve-cent piece will close contacts |633. In initiating a call any coil which is deposited will close contacts il. The closure of contacts |94 prepares a circuit for the operation of relay |65. This circuit may be traced from ground, through battery at the central ofce, resistance |01, top back contact and armature of relay IGS. top winding of relay |99, variable resistance l) and over the tcp loop conductor connecting the central oiiice with the teletypewriter pay station, conductor H2, contacts |04, winding of relay H35 to the righthand armature or key H3, which is disengaged from the path which extends to ground through its cooperating contact. The closure of contacts H34 also establishes a parallel branch extending through the windings of coin collect magnet H, coin return magnet H5, left-hand outer armature and back contact of relay IE6, con- -ductor Ill and through the right-hand outer armature and back contact of relay H9 to ground. The energization of the top winding of Vrelay |89 in the circuit just traced closes a cirtact and armature of yrelay |20 and the filament of lamp |2| to ground, lighting lamp i2| as a signal that the pay station subscriber is calling the central station. The operation of relay |25) also closes a circuit from ground, through battery |22, resistance |23, top armature and front Contact of relay I, bottom inner back contact and armature of relay lilt, variable resistance |26, printer receiving magnet |25, right-hand cuter back contact and armature of relay i, tcletypewriter sending contacts |25, contact and .armature of break key l2? to a parallel circuit.

One branch of said circuit extends through contacts |31 which can be opened momentarily by the teletypewriter receiver on 4reception of a train of signals corresponding to the code for the up- .per case S by the teletypewriter receiver and through the left-hand inner back contact and armature of` relay H5. The second branch extends through the winding of relay iii.. The parallel branches join and the circuit extends through the continuity contacts of recall key mand through the right-hand outer armature and back contact of relay Wto ground.

The pay station subscriber will now operate key i3 so as to close the path heretofore'traced, through the winding of relay |25, to ground. This results in the operation lof relay The operation of relay H35 in turn causes the operation of relay H9 over a path'extending from the right-hand side of the alternating current power supply |23, through the winding or relay E9 and the front contact and armature of relay |55 to the left-hand side of the power source |23. This causes the operation of relay H9. Relay H9 locks in the yoperated position over a circuit from the right-hand side of power Source |28 through the winding, left-hand armature VVand front contact of relay M9, through contacts |25, which are arranged so that they can be opened momentarily in response to the reception of a train of code signals by the teletypewriter corresponding to the upper case H, to the leithand side of the power source |23. Theoperation. of'relay H9 disconnects ground from theV windings of coin collect magnet ||li and coin return magnet H. The operation of relay H9 further short-circuits magnets Ht and '..ias well as coin collect contacts it when the top loop conductor is closed through the right-hand outer front contact and armature of relay H9. The closure of these contacts establishes the pay station transmitting loop by extending the loop through these contacts, through the continuity contacts of recall key i8, left-hand inner armature and back contact of relay l'i, contacts itl, break key |21, transmitting contacts |25, righthand outer armature and back Contact ci relay H6, receiving magnet |25, variable resistance |24, bottom inner armature and back contact of relay |28, continuity contacts of relay |29 and resistance |54 to ground. The operation or relay ||9 also closes the power circuit to the teletypewriter motor |32. This circuit may be traced from the right-hand side of power supply |28, through the windings of motor itil, the righthand inner front Contact and armature of relay H9 to the left-hand side of the power supply |28. This starts motor |35. The operation of relay i9 also establishes a circuit which extends from the left-hand side of power source through the right-hand inner armature and front contact of relay H9 and the top winding of transformer |55 to the right-hand side of power source |28. Alternating current supplied through the transformer |55 is rectified in rectier it. The rectier supplies direct current to the coin collect apparatus over a circuit which extendsY from the bottom terminal of the rectifier through conductor |53, through the start magnet lill of the rotary distributor |22, to the top front contact of relays |33, |34 and |35 in parallel. These contacts are open at this time. The'cooperating armatures of these relays are connected in parallel and the circuit extends through conductor |51 to the top terminal of rectiiier |56.

After thepay station transmission loop has been established, relay m9 remains in the operated condition due to the eiect of current flowing through its top winding.

The central station operator answers Refer now to Fig. 2.

When the cord circuit per Fig. 2 is idle, the circuits through both the top and bottom windings of repeater relays 2.65 and 20@ are open so that no current flows in any of these wind-ings. The armature of each of these relays is shown in engagement with its spacing contact.` When the circuit per Fig. 2 is conditioned for communication, the armatures of relays 235 and 2% will each be in engagement with its marking contact. How this is accomplished will be described below.

Upon noting the lighted line lamp, a switchlboard operator at the central station answers the call by operating either of two typing keys 292 or 223 in her cord circuit per Fig. 2 and then inserting plug 22| of Fig. 2l into jack |3 of Fig, l.

It is to be understood that there are -a plurality of cord circuits such as Fig. 2 available at each operators position in the central oflice. Each operator has only one operators vposition circuit per Fig. 3 by means of which she may communicate. Upon theV selection of a particular cord at her position for use in responding to a particular call, it is necessary for the operator at the posi- Fig. 3 are arranged for teamwork. By this is meant that they are arranged in such manner that an operator at a position adjacent the position in which a particular cord has been selected for answering a call may connect her single operators position circuit such as Fig. 3, to the selected cord in the adjacent position so as to cooperate with the operator thereat during intervals of heavy load.

In order to permit this cooperation, each cord circuit is equipped with two keys, one of which is used to connect the operators position circuit at the same position and the other of which is used to connect the operators position circuit at an adjacent position to the cord circuit. Key 202 is used to connect the operators position circuit at the same position and key 203 is used to connect the operators position circuit at an adjacent position to Fig. 2.

It will be assumed that the central station operator actuates key 202 to its alternate position so as to connect her own operators position circuit to the cord circuit per Fig. 2.

When plug 20| is inserted in jack |38, a circuit is established which may be traced in Fig. 1 from ground through the winding of relay |08 and the sleeve of jack |36 into Fig. 2 through the sleeve of plug 20|, top Winding o1" relay 201 and Winding of relay 208 to grounded battery. Relays |08, 201 and 208 are operated. The operation of relay |08 disconnects loop conductor from the path which extends through the top back contact of relay |08 to positive battery and connects the top loop conductor through the top armature and iront contact of relay |08 to the tip of jack |36. The bottom loop conductor of Fig. 1 is disconnected from the path through the bottom inner armature and back contact of relay |08 and connected through the bottom inner front contact of relay |08 and through the bottom Winding of relay |09 and resistance |23 to negative battery |22. When the loop circuit is extended through the bottom winding of relay |09, relay |09 releases. This, in turn, releases relay |20 by breaking the connection to ground through the front contact and armature of relay |09. The release of relay |20 opens the circuit through the lament of lamp |2| as the bottom armature of relay |20 is disconnected from its front contact and lamp |2| is extinguished.

The operation of relay 288 closes a circuit from ground through the top front contact and armature of relay 208 and the winding of relay 209 to battery, operating relay 209. The operation of relay 203 establishes a circuit from negative battery through the bottom inner armature and front contact of relay 203, resistance 2|2 and the top winding of relay 2|3 to ground, operating relay 2 I3. The operation of relay 2|3 establishes a circuit from ground through the top outer front contact and armature f relay 2|3 to a parallel circuit comprising resistance 2M and condenser 2 5 and then in series through resistance 2 |6, the bottom winding of relay 206, through the armalture and spacing Contact of relay 205 and resistance 2|"| to negative battery. A circuit is also y'established from ground through the top inner front contact and armature of relay 213 to a parallel circuit comprising resistance 2|8 and condenser 2 |9 and then in series through resistance 220, the bottom Winding of relay 205 through the armature and spacing contact of relay 205 and resistance 22! to negative battery. A circuit is also established from negative battery through .resistance 222, the bottom outer front contact and armature of relay 2|3, resistance 223, the continuity contacts associated with the top outer armature of relay 224, the continuity contacts associated with the top armature of relay 225, resistance 225, top winding of relay 206 through the armature and spacing contact of relay 205 and resistance 2|'| to negative battery. The circuit Which extends from negative battery through resistance 228 and the bottom inner front contact and armature of relay 2 I3 through resistance 229 is opened as relay 221 is released and relay 200 is operated.

The operation of the typing key 202 closes a circuit from ground through the bottom armature and front contact of key 202, through the Winding or" relay 230to battery, operating relay 230. This extends the transmission path Which will be traced below through the operators position circuit.

The transmission path interconnecting Figs. 1, 2 and 3 may he traced from ground in Fig. 1 through battery |22, resistance |23, bottom winding of relay E02, bottom inner front Contact and armature of relay H38, variable resistance |24,

`receiving magnet |25, right-hand outer front contact and armature of relay HS, transmitting contacts 26 and break key |2'l to a two-branch parallel circuit. Branch of this parallel circuit extends through the winding of relay ||6. Branch 2 of this parallel circuit extends through contacts |8i. These contacts are controlled by a functional lever in the teletypewriter receiver which in turn responds to a train of signals corresponding to the code for upper case S. Branch 2 continues through the left-hand inner `back contact and armature of relay H5 Where it joins with branch i. The cir-cuit continues through the continuity contacts of recall key |18, the right-hand outer armature and front contact of relay H9, through the top loop conductor variable resistance H0, top winding of relay |09, top armature and iront contact of relay |08, tip of jack |30, tip of plug Zli, top armature and front contact of relay 200, resistance 260, through the continuity contacts associated with the top outer armature of relay 230, which continuity contacts are closed when relay 230 is operated in order to connect the operators position circuit to the cord per Fig. 2. The circuit continues through conductor 232 in Fig. 2, which connects to conductor 332 in Fig. 3, through the armature and back contact of key 333, through the armature and back contact of key 334, through the top outer armature and back contact of relay 335, through the continuity contact associated with the top armature and the bottom inner armature oi' relay 336 in parallel, through the top back contact and armature of relay 337, through theV top winding of relay 338, the transmitting contacts 330 of the printer in the operators position circuit, the armature and back contact of lbreak key 3&0, the continuity contacts associated With the top armature and bottom inner armature of relay 34| in parallel, through conductor 342 which connects to conductor ft2 in Fig. 2, through the top inner armature and front contact of relay 230, through the continuity contacts associated with the top inner armature of relay 23| and the top outer back contact and armature of relay 23| in parallel, top Winding of relay 205, the armature and spacing Contact of relay 205 and resistance 22| to negative battery.

In tracing the path which extends through the top Winding of relay 205, it was shown that both Aends of the path are terminated in negative` bat.

tery so that no current flows through the top winding. ln tracing the path which extended through the top winding of relay E, it was `shown that both ends of the path are also terminated in negative battery so that no current ows through the top winding of relay 265 for ythis condition. The circuit through the bottom .winding of relay 265, as well as that through the `bottom Winding of relay 2%, when the armatures of these relays are inengagement with their spacing contacts, as shown, is terminated in ground at one end and negative battery on the opposite end in each instance. When no current flows through the top Winding of each of these relays,

-theefect of current flowing from negative battery to ground through the bottom winding in each instance actuates the armature of each of these relays to engage with its alternate or marking contact. When the armature of relay Zi `is in engagement with its left-hand or marking contact, positive battery is connected through resistance 2523 and the left-hand or marking contact and armature of relay '292. rI he other end of the loop circuit heretofore traced is treminated, as has been shown in negative battery iZi. For this condition the batteries connected to each end of the transmission circuit through the subscribers station per Fig. l and the answering end of the cord per Fig. 2 are in series-aiding relationship. The effect of this current flowing through the top winding of relay 2i35 tends to maintain the armature of relay 2te in engagement with its right-hand or marking contact. 'When the armature of relay 265 is in engagement with its right-hand or marking contact, positive battery is connected through resistance Elio to the right-hand or marking contact and armature of relay 2%. For this condition the batteries connected to each end of the circuit extending through the top winding of relay Zilli are in serien aiding relationship and the eiTect of current owing through the top winding of relay D5 actuates the armature oi relay 2de to engage with its left-hand or marking contact. When the armatures of relays Zilli and 2535 are in engagement with their marking contacts, positive battery is connected to one end of the circuit extending through the bottom winding of each of relays Ztl-5 and 286 and ground is connected to the opposite end of each circuit. The effect of the current through each bottom winding for this condition tends to actuate the armature of relay 265 and the armature or" relay 2d@ to engage with its corresponding spacing contact. The eiiect of the current through the top winding of relays 2El5 and 2135 is dominant, however, so that the armature of each of these relays is maintained in engagement with its marking contact.

Prevention of interference between answering cords Y lpositions, so that lamp ii is lighted at a plurality of answering positions to enable any one of several operators to respond to the incoming line signal when a subscriber at teletypewriter pay station, per Fig. 1, initiates a call. ln addition to jacks, such as E35, located at a plurality of answering positions, a number of similar' jacks, connected in multiple with jack |36,

appear at a plurality of'operators positions in another switchboard wherein calls originated by other subscribers may be completed to a particular subscribers station such as the station connected to Fig. 1. The circuit herein provides protection against the simultaneous connection of more than one cord, per Fig. 2, to a subscrbers circuit, per Fig. 1. Ii a second plug, such as 20|, of a second Fig. 2 is inserted into one of the multiple jacks, such as 135, While the plug of a rst Fig. 2 is so connected, the relay corresponding to relay 2838 in the second cord will operate, but the relay corresponding to relay 201 in the second cord will not operate, due to the shunting effect of relay 2GB in the rst cord. The operation of the relay corresponding to relay 2&3 in the interfering cord will, in turn, operate the relay corresponding to relay 269 in the interfering cord. At the same time a circuit is established in the interfering cord from ground through the bottom armature and front contact of the relay corresponding to relay 233, through the winding of the relay corresponding to relay 2H, through the bottom back contact and armature of the relay corresponding to relay 'l to negative battery. This o-perates the relay corresponding to relay 2li in the interfering cord.

The operation of the relay corresponding to relay 2li in the interfering cord closes a circuit from positive battery through the resistance corresponding to resistance 243, through the top front Contact and armature of the relay corresponding to relay 2H, through the resistance corresponding to resistance 2GB and over a circuit corresponding to the circuit traced in Fig. 2 above, through the top winding of the relay corresponding to relay iii and the armature and marking contact oi the relay corresponding to relay il. Since both ends of the circuit through the top winding of the relay corresponding to relay 2% in the interfering cord are terminated in the same positive battery, no current will flow through this winding in the interfering cord. The eiect ci current flowing from positive battery through the marking contact and armature of the relay corresponding to relay Zilli and the bottom Winding of the relay corresponding to relay 2%5 to ground, when no current i'lows through the top winding of the relay corresponding to relay 2525 actuates the armature of the relay corresponding to revlay 2i5 to engage with its left-hand or spacing Contact. When the armature of the relay corresponding to relay is in engagement with its left-hand or spacing contact, no current will ow through the top winding of the relay corresponding to relay EQS, since both ends of the circuit are terminated in negative battery. The effect of current owing through the bottom Winding for this condition maintains the armature of the relay corresponding to relay 2%' in engagement with its left-hand or marking contact. Since the armature of the relays corresponding to relays and 23 in the interiering cord are maintained in this condition, namely, the armature of the relaf,7 corresponding to relay 2% in engagement with its spacing Contact, and the armature of the relay corresponding to relay 2% in engagement with its marking contact, due to the eiect of current conditions, supplied from the interfering cord itself, it is not possible to transmit through the interfering cord.

When an interfering cord is connected to a 2,345,851 line circuit, a visual signal is provided in ther cperators position circuit to indicate the condition. The manner in which this is performed is as follows:

The operation of the relay corresponding to relay 2H in the interfering cord establishes a circuit from negative battery through resistance 245 to the armatures of the relays corresponding to relays 230 and 23! in the interfering cord. Assuming that the key corresponding to key 202 in the interfering cord has been operated to connect the interfering cord to the operators position circuit in the same position, the circuit will be extended through the bottom inner armature and front contact of relay 230, through conductor 246 which connects to conductor 346 in Fig. 3 and through the winding of a relay, such as 341, in the position circuit connected to the interfering cord, to ground, operating the relay, such as 341. This closes a circuit from ground through the armature of the relay, such as 341, through a resistance, such as 348, and the nlament of a lamp, such as 349, to battery, lighting the lamp such as 349 as an indication of the interfering condition.

When the interfering cord is removed the relays in the interfering cord which have been operated will be restored to normal.

Calling subscriber and central station operator communicate The transmission circuits extending through Figs. 1, 2 and 3 are now in condition so that communication may proceed between the calling subscriber at the pay station and the operator at the central station. The subscriber at the pay station types the necessary information to enable the operator at the central station to complete the call. As the various characters are transmitted, the transmitting contacts I 26 are set in various combinations corresponding to the code of the desired characters and the transmitting path through these contacts is opened and closed in conformity. y

In the operators position circuit, per Fig. 3, key 350 is actuated to its alternate position. This closes a circuit from battery through resistance 35|, the bottom winding of relay 338 and through the top inner armature and front contact of key 350 to ground.

When the circuit, per Fig. 3, is in such condition that key 350 is actuated to its alternate position so that current flows through the bottom winding of relay 338 and the circuit through the top winding of relay 330 is open so that no current flows through the top winding, the armature of relay 333 is actuated so as to engage with its left-hand or spacing contact, as shown. When the circuit extending through the top winding of relay 338 is closed and its two ends are connected to batteriesoi opposite polarities, the effect of current owing through the top winding of relay 33t preponderates over the effect of current flowing through the bottom winding of relay 338 and the armature of relay 338 is actuated so as to engage with its right-hand or marking contact. Relay 352 is a slow-release relay. A circuit may be traced from ground through the bottom armature and iront Contact of key 350, the winding of reiay and resistance 314 to negative battery. When the armature of relay 338 is in engagement with its left-hand or spacing contact, this path is shunted by a circuit extending from ground through the armature and front contact of key 353, `the armature and left-hand orspacing con-` tact of relay 330 to resistance 314 and thence to negative battery. Relay 352 releases too slowly to follow spacing signals of normal duration. Relay 352 will release, however, on spacing signals of protracted duration, such as break signals. During normal communication, therefore, relay 352 remains operated. As relay 338 follows the communication signals, ground is connected from the bottom armature and front contact of key 350, through the armature and right-hand or marking contact of relay 338 to a circuit which extends through the armature and front contact of relay 352, through resistance 353, the winding of receiving magnet 354 and resistance 310 to positive battery. For this condition the winding of receiving magnet 354 is energized to record a marking signal in the teletypewriter receiver. When the armature of relay 338 is actuated so as to engage with its left-hand or spacing contact, the circuit through the winding of receiving magnet 354 is open and the magnet is deenergized to record a spacing signal. Thus, signals transmitted from the pay station teletypewriter are recorded in the teletypewriter receiver in the operators position circuit at the central station. Relay 205 in the cord circuit, per Fig. 2, follows these signals also, but this is ineiective to produce any further result at this time, as the plug 204 is not connected as yet to any cooperating circuit. As the armature of relay 205 is operated between its marking and spacing contacts, the armature of relay 206 is maintained in engagement with its left-hand or marking contact. This, as is well known, is due to the fact that when the armature of relay 205 is connected to its right-hand or marking contact, the effect of current flowing through the top winding of relay 206, which effect tends to operate the armature of relay 206 so as to engage with its left-hand or marking contact, preponderates over the effectV of the current flowing through bottom winding ofrelay 290 which latter effect tends to actuate the armature of relay 20S to engage with its righthand or spacing contact. When the armature of relay 205 is actuated so as to engage with its left-hand or spacing contact, under which condition negative battery is connected to both ends oi thecircuit extending through the top winding of relay 205 so that no current flows through the top winding, theV eiect of the current iiowing through the bottom winding of relay 206 is reversed so that the armature of relay 205 is now maintained in engagement with its left-hand or marking contact.

After the operator at the central station has received the information requisite to completing the connection to the called party, she will extend the connection. The calling party may wish to be connected to another party whose line is connected directly to the same central station at which Fig. 2 is located. In this case, the operator at the central station, where Fig. 2 is located, may complete the connection directly to the called partys line. It will be assumed herein that such a connection is desired. It is to be understood that the circuit, per Fig. 2, may be used to extend a call to a more remote central terminal for completon by means of a trunk circuit extending toward the more remote `central terminal. As it is not necessary to an understanding of the invention herein, the manner in which Fig. 2 cooperates with the trunk circuit where completion to a remote subscriber is desired will not be described; such extension involves circuits and operating practices in commercial use as well as disclosed in prior patents vand will be understood by persons skilled in the art.

Testing called line Before the central station operator completes the connection to the called party, she Will test the called line to determine Whether or not it is available. A number of conditions may prevent the called line from being available. It may be temporarily engaged in communication with another party. This condition is known as busy. It may be out of order. -The subscriber at the station to be called may be practicing. The circuits herein are arranged to indicate all of these conditions by means of special identitying signals. First the busy test and characteristic signal Will be described.

The cord circuit, per Fig. 2, is arranged so that a busy test is provided with each end of the cord. Before inserting the plug associated with either end vof Fig. 2 into a jack associated with a particular line circuit, the operator will momentarily connect the tip of the plug which she is using to the sleeve of the particular line. be assumed that the circuit, per Fig. 4, is to be used for the called line. If Fig. 4 is busy, another cord will be connected to some one of the multiple of appearances of jack |36. Negative battery, such as 241 in the other cord, will be connected through a resistance, such as 248, and the sleeve of a plug, such as 2M, to the sleeve of a multiple appearance of jack |35 and a circuit Will be extended from said sleeve through the tip of plug Zilli ofthe present Fig. 2, through the armature and back contact of key 249, the top inner armature and back contact of relay 224 to 'the bottom inner armatures of relays 23il and 23l in parallel. Depending upon Whether the home or team cperators position circuit is connected to Fig. 2, relay 235] or relay 23| will be operated, as key 262 or key 293 is operated under these circumstances. It has been assumed that key 282 and relay 23B are operated and the circuit Will, therefore, be extended through the bottom inner armature and front contact of relay 23B, through conductor 246 into Fig. 3 where it connects with conductor 343 and is extended to ground through the windingof relay 341. In response to the negative battery connected to its Winding, relay 341 will be actuated so that its armature .engages with its right-hand contact. This, in turn, will light lamp 349 as heretofore described. Attention is called to the fact that relay 341 is operated and lamp 349 is lighted to indicate either an interfering cord condition or a busy test condition.

If the line is busy due to being connected up for practice, a positive potential will be present on the sleeve of the called line. Under these circumstances the armature of relay 31| Will be actuated so as to engage .with its right-hand contact and a circuit will be closed from ground through the armature of relay 31|, Winding of relay 313, bottom armature and back contact of relay 351 and through resistance 358 to battery, operating relay 313. 313 will close a circuit from ground through the :front contact and armature of relay 313, through buzzer 312, lament of lamp 31@ and power source 315 to ground, lighting lamp 31B and operating buzzer 312 as an indication that the line Which has been called is engaged in practice and that the operator may insert her plug and proceed with the call. Attention is called to the fact that the positive potential supplied from The operation of relayV It Will the sleeve of a busy line, While sufficient to operate the armature of relay 31| is insufficient to operate relay 351.

If the line is out of order, a positive potential will be present on the sleeve of greater magnitude than in the case of the practice circuit connection and both relays 31| and 351 will be operated. Under these circumstances a circuit Will be established which extends from ground through the armature of relay 31|, Winding of relay 313, armature and rontcontact of relay 351, resistance 348 and the lament of lamp 3&9 to battery. This operates relay 313 and lights lamp 349. The operation of relay 313, in turn, operates buzzer 312 and lights lamp 31S, as heretofore described. The operation of the buzzer and the lighting of the two lamps indicates the outof-order condition.

It is to be understood, of course, that the necessary sleeve potentials are supplied from outof-'order cords and practice cords which are temporarily connected to one of the multiple appearances of jack |36 during the out-oi-order or practice intervals.

Central station operator completes call to called line If the operator iinds that the called line is available, she will complete the call to the called line by inserting plug 234 into jack 33. A circuit Will, thereupon, be completed from battery through the Winding of relay 224, sleeve of plug 204, sleeve of jack |36 and the Winding of relay IBS' to ground, operating relays '224 and |98. The operation of relay 224 closes the transmission circuit through the calling side of the oord at the top outer armature and front contact of relay 224. t also disconnects the busy test lead at the top inner armature and back contact oi relay 22d. The operation of relay 224 also closes a circuit from negative battery through the lower make contact and armature of relay 224, resistance 235 to a parallel circuit. One branch of the parallel circuit extends through the winding of relay 253, top back contact and armature of relay 254, to the top inner make contact of relay 252 which is open at this time. The other branch connects in parallel to open contacts on keys 202 and 263 and on relay 254.

In the subscribers lineY and pay station, per Fig. 4, the operation of relay |98 establishes a circuit from negative battery |22 through resistance lll-3 bottom Winding of relay |99', bottom inner front contact and armature of relay H38', variable resistance |24', through the bottom loop conductor extending from the central terminal to the called subscribers pay station, receiving ma-gnet |25', left-hand outer back contact and armature of relay HE', the teletypewriter transmitting contacts |26', and break key |21 to a two-branch parallel circuit. The rst branch of said parallel circuit extends through the winding of relay i'; the second branch extends through contacts |31', which are controlled in response to the reception of a train of signals corresponding to the upper case S by the teletypewriter at the called subscribers station, and through the right-hand inner back contact and armature of relay l I6. The two branches thereupon join and the circuit continues through the continuity contacts of recall key i8 and through the left-hand outer armature and back Contact of relay i9 to ground. The circuit through the upper winding of relay |09 is open, for direct current, at the lefthand outer make contact of relay HS', so that the top Winding of relay H15' is notV energized.

Relay |09 operates due to the effect of current flowing through its bottom winding. This establishes a circuit from ground through the armature and front contact of relay |09', the ring conductor of jack |35', ring of plug 204 and through the winding of relay 252 to battery, operating relay 252. Relay 253 remains unoperated at this time as the circuit through its winding which may be traced from battery through the bottom front contact and armature of relay 224, resistance 235, winding of relay 253, top back contact and armature of relay 254 and through the top inner front contact and armature of relay 252 to ground is shunted by a circuit which extends through the top front contact and armature of key 202 through conductor 255 into Fig. 3, Where it connects with conductor 355, through the bottom outer back contact and armature of relay 34| to ground. It is to be understood that typing key 202 is operated before plug 204 is inserted into jack |35'. The operation of relay 252 closes a circuit from ground through its bottom outer front contact and armature and the filament of lamp 256 to ground. Lamp 256 is lighted as a supervisory signal to indicate that the called subscriber has not yet responded. The operation of relay 252 also closes a circuit from ground through the bottom inner front contact and armature of relay 252 to the night alarm circuit indicated by a rectangle. The night alarm circuit is arranged so that it may be connected in series with the conductor just traced, by the operation of a switch in said circuit, to provide an audible or visual signal, or both, during periods of light load when an operator is not stationed at each position in the switchboard at the central station.

When the transmission conductor in the calling side of the cord is extended into Fig, 4, it is essential that the armature of relay 206 be maintained in engagement with its marking contact. It has 4been shown, in tracing the circuit of the transmission conductor in Fig. 4, that prior to the time when the subscriber at the called pay station responds, the transmission conductor in the line and station circuit which connects to the transmission conductor in the calling side of the cord, is open at the left-hand outer make contact of relay H9'. In order to maintain current in the top winding of relay 206, it is necessary to connect negative battery to the righthand side of the winding until the called station responds. Relay 252 performs this function when it closes its top outer armature and front contact. A circuit may thereupon be traced from negative battery through resistance 222, bottom outer front contact and armature of relay 2|3, resistance 223, top outer armature and front contact of relay 252 to the right-hand side of the Winding of relay 209 from which point the circuit has heretofore been traced.

Key 249 is operated so as to engage its alternate contacts to ring the called subscriber. A circuit may thereupon be traced from ground through a source of alternating current 25|, the filament of lamp 250, right-hand front Contact and armature yof key 249, tip of plug 204, tip of jack |35', top front contact and armature of relay |08', top winding of relay |50', variable resistance I0' and the top loop conductor I' to a parallel circuit consisting of two branches. One branch extends through condenser |53' and the winding of relay |50'. The other extends through con denser |40 and ringer MI. The branches jo-in and the circuit continues through the lefthand outer armature and back contact of relay H9' to ground. This operates ringer |4|' as a signal to the called station and also operates relay |50' while the ringing continues. In the cord circuit per Fig. 2 the operation or" ringing key 249 also operates relay 254 over a path which may be traced from negative battery through resistance 222, bottom outer front contact and armature of relay 2|3, bottom winding of relay 254, left-hand make contact of ringing key 249, top outer armature and front contact of relay 224, top outer armature and front contact of the continuity contacts of relay 225, resistance 225, top winding of relay 255, armature and right-hand or marking contact -oi relay 205 and resistance 244 to positive battery. When relay 254 operates, it locks over a circuit from battery through its top Winding, top front contact and armature of relay 254. to ground through the top inner front contact and armature of relay 252. The operation of relay 254 breaks the path heretofore traced which extended through the Winding of relay 253,

In response to the ringing of the call bell at the called subscribers station, the called subscriber will operate key |I3' at the called station momentarily. A circuit may thereupon be traced from the right-hand side of the power source through the right-hand armature and front contact of key II3', through the left-hand outer armature and front contact of relay |50' and through the Winding of relay I I9' to the opposite side of the power Source operating relay I I9'. The operation of relay I|9' closes the loop through the called subscribers station at the left-hand outer armature and back contact of relay ||9'.

The transmission circuit through the` calling end of the cord and the called subscribers loop is thereupon established. This circuit may be traced from positive battery, through resistance 244, in Fig. 2, right-hand or marking contact and armature of relay 295, top winding of relay 206, resistance 225, top continuity contacts of relay 225, top outer front contact and armature of relay 224, back Contact and armature of key 249, tip of plug 204, tip of jack |35', in Fig. 4, top front contact and armature of relay |08', top Winding of relay |09', Variable resistance H0', top loop conductor extending to the called station, left-hand outer fro-nt contact and armature of relay I |9', continuity contacts of recall key ||8', right-hand inner armature and back contact of relay II 5', contacts |31', contacts of key |21', teletypewriter transmitting contacts |26', left-hand outer armature and back contact of relay H6', winding of receiving magnet |25', bottom loop conductor extending back to the central station, variable resistance |24', bottom inner armature and front Contact of relay |93', bottom winding of relay |09' and resistance |23' to negative battery |22'. Attention is called to the fact that while the marking condition prevails the two ends of this circuit are terminated in batteries arranged in series-aiding relationship so that current flows around the called station loop during the marking condition. The path. was shown to extend through both the top and bot-` tom windings of relay |09. For this condition the armature of relay |09' is released. This breaks the circuit which was heretofore traced through the winding of relay 252, in Fig. 2, and relay 252 releases. This in turn releases the holding circuit heretofore traced by means of which armature of relay 205 was held in engagement with its marking contact. The armature of relay 205, however, continues to remain in engagement With its marking contact as negative battery 22', in Fig. 4, has been substituted for the negative battery which has been disconnected through the operation of relay 252. The operation of relay 2,52 further releases relay 254, which has been maintained operated through the locking circuit of relay 254, which-extends to ground through the top inner armature of relay 252. The reiease of relay 252 further extinguishes the supervisory lamp 253 associated with the calling end of the cord, as an indication that the called subscriber has responded. 'The release of relay 252 further disconnects the night alarm circuit at the bottom inner back contact and armature of relay 252.

Operator returns coin After obtaining the connection to the desired called party, the switchboard operator splits the cord by operating the splitting key 356 in the operators position circuit per Fig. 3 to the answering position, which associates the position circuit with the answering end of the cord circuit per Fig, 2 and the calling subscribers circuit, while excluding the called subscriber from the connection. The operation of key 355 closes a circuit from ground 345 through the top armature and front contact of key 355 and the winding of relay 33| to battery operating relay 34|. The operation of relay 34| establishes a circuit which extends from negative battery 363, through resistance 359, top armature and make Contact of the continuity combination of relay 34|, conductor 342 into Fig. 2 where it extends through conductor 242, top inner armature and make contact of the continuity combination of relay 230, which relay is operated, top outer back Contact and armature of relay 23|, top winding of relay 205, armature and left-hand or marking contact of relay 206 and resistance 233 to positive battery. Attention is called to the fact that both ends of this circuit are terminated in batteries of opposite polarities so that current flows through the top winding of relay 205 to maintain the armature of relay 205 in engagement with its right-hand or marking Contact. This prevents a spacing signal from being transmitted toward the called station by maintaining the repeater in the cord circuit closed during the splitting operation while the central station operator communicates with the calling subscriber. The operation of relay 34| also establishes a circuit which extends from positive battery, through resistance 310, bottom back contact and armature of relay 335, bottom inner armature and front contact of relay 34|, break key 343, transmitting contacts 339, top winding of relay 333, top armature and back contact of relay 33's', top continuity contacts of relay 336, top outer back contact and armature of relay 33 5, back contact and armature of key 334, back contact and armature of key 333, conductor 332, into Fig. 2, where it connects with conductor 232 and the circuit is extended through the top outer front and rear contacts of the continuity contact combination of relay 230, resistance 250, top front contact and armature of relay 239 to the tip oi plug 20| which connects to the tip of jack |35. From this point the circuit extends around the calling subscribers loop which has heretofore been traced to negative battery |22.

When the circuits interconnecting the calling subscribers station and the operators position circuit at the central station are arranged for communication, the operator at the central station will inform the calling subscriber of the amount which is to be deposited in the coin collection device. The central station operator vwill type the amount on her teletypewritei` transmitter and it will be recorded by the teletypewriter receiver at the calling station.

Following this instruction the central station operator transmits an upper case S signal from her teletypewriter. In response to this signal contacts I3? in Fig. l, which are under control of the S type bar, are momentarily opened. rlhis removes the shunt from around the winding of relay H6 and relay H5 operates. Relay IIS when operated locks through its right-hand inner front contact and armature. Contact |31 will reclose but, since relay I l@ is locked over another path to be subsequently traced, the closing o contacts |33' is ineffective. Relay ||6 is a slowto-release relay and does not release on teletypewriter signal pulses. The operation of relay II6 also short-circuits the teletypewriter keyboard contacts |26 and the break key contacts |21 so that the pay station subscriber is not permitted to communicate until the amount designated by the central station operator has been deposited and recorded at the central station.

The operator at the central station will now operate key 333 in Fig. 3. This establishes a circuit from a high potential positive battery 353 through the iilament of lamp 335, winding of relay 35|, make contact and armature of key 333 to conductor 332. Conductor 332 connects to conductor 232 in Fig. 2 and the circuit continues through the top continuity contacts of relay 230, resistance 23B, top continuity contacts of relay 209, tip of plug 23 i, tip of jack |33, top front contact and armature of relay |38, top winding of relay |09, variable resistance Iii] and top loop conductor I I to the junction with conductor II2. Here the circuit forms into parallel branches. One branch continues through the right-hand armature and front Contact of relay I3, through the continuity contacts of recall key I I8 and the winding of relay H6. The other branch extends through conductor H2, contacts |04, coin collect magnet I I4, coin return magnet I I5, and the lefthand outer armature and front contact of relay IIS to a junction with the i'irst of the parallel branches above traced. The circuit continues through the right-hand inner make contact .and armature of relay H6, right-hand outer armature and front contact of relay IIS, conductors I 43 and 44, stop segment of distributor |32, outer brush |45, inner brush |45 of the distributor |32, inner solid ring ISI of distributor |32, conductor |41, receiving magnet |25, the bottom loop conductor variable resistance IM, bottom armature and front Contact of relay |28, -bottom winding of relay |09 and resistance |23 to negative battery |22. As a result of the high positive potential impressed on this circuit, coin return magnet I I5 will operate and the coin originally deposited by` the pay station subscriber to initiate the call will be diverted into the coin return hopper where it may be retrieved by the pay station subscriber.

The lpay station subscriber now deposits the amount which has been requested by the central station operator. It will be assumed that twentyiive cents has been requested and that a twentyve cent piece is deposited in the coin collection device |00. In response to this contacts |03 will be closed. This establishes a circuit from the top terminal of the rectifier |53, through contacts |03, through `the winding of relay |35 and contacts |48 back Yto the bottom terminal of the'rectier |56; Relay |35-operates and locks through its top inner iront contact and armature asthe opposite terminals of its winding are connected tothe opposite terminals of rectifier |55. It is to be understood that contacts, such as |03, when operated in' response to the deposited coin are closed only momentarily. The operation of relay |35 also establishes a circuit for the operation of magnet 3| from the bottom terminal of rectifier |56, through magnet |3|, through the top outer make contact and armature of relay |35 to the top terminal of rectifier |56. When magnet |3| operates, it withdraws the stop latch |49 from the path of the rotary arm |40 of the distributor and the distributor brush arm |40 rotates once. As the brush arm |40 rotates, the path connecting conductors |44 and |41 in the loop is open or closed, depending upon the manner in which the group of contacts cooperating with the bottom armature of relay |35 are connected to segments to `5 of distributor |32. When the brush arm sweeps across the start segment an open pulse is transmitted as the path between conductors |44 and |41 is open. When the brush arm sweeps across segment l, a circuit is established from conductor |44 through the bottom armature and lowest front contact of relay |35, segment of the distributor, brush |45, brush |46 and inner solid conducting ring 4| to conductor |41. Since the station loop is thus maintained closed, a marking pulse is transmitted while the distributor brush arm |40 sweeps across segment Similar circuits are established through segments 2, 3 and 5 upon the operation of relay |35. Since no path is closed through segment 4 upon the operation of relay 35, an open or spacing pulse will be transmitted as the brush arm sweeps across lthis segment. A train of pulses identifying a particular character, such as Q, will thereupon be impressed upon the loop and will be recorded by the teletypewriter receiver at the central station as well as on the receiver at the calling pay station itself. As the brush arm sweeps by contacts |48 these contacts are opened. This breaks the holding path for relay |35. Relay 35 releases, in turn deenergizing magnet |3|, releasing stop lever |49, which engages with the rotating distributor arm |40 and stops its rotation.

The subscriber at the pay station is instructed to deposit o ne coin at a time and Wait until a letter characterizing it has been printed on his home receiver before the succeeding coin is deposited. The mechanism is shown arranged in such manner that coins of any of three denominations may be inserted in the collection device |00 and a record will thereupon be provided at the central station and on the pay stam tion subscribers receiver. The manner in which the device may be expanded to accommodate a larger number of coins, as well as to provide a corresponding record, should be obvious from the above to any one skilled in the art. Further, by a minor wiring modification, it is possible toarrange the mechanism in such manner that a plurality of'coing may be inserted in the collection device simultaneously whereupon a single character designating the total amount deposited will be recorded.

`Operator removes lock-out condition on. station teletypewriter After the central station operator has veriiied the amount of money deposited inthe coinbox at-the station by observing thecharac-ters von her teletypewriter receiver, the central station operator transmits a break signal from her teletypewriter and restores the splitting key 356, in Fig. 3, as Well as the home position typing key 202 in Fig. 2. The opening of the transmission circuit for the transmission of a break signal releases relay ||6, in Fig. 1. 'Ihe release of this relay removes the short circuit around the teletypewriter transmitting contacts |26 and the break key |21 as the right-hand inner and righthand outer armatures disengage from their respective front contacts. The release of relay 6 further disconnects the circuit extending through the automatic coin indicator apparatus, heretofore traced, when the right-hand outer armature of relay it disconnects :from its back contact. The loop circuit through the teletypewriter pay station in Fig. l is now arranged in such manner that it extends in series once more through break key V| 21, transmitting contacts |26, and the winding of the receiving magnet |25. The operators position circuit, per Fig. 3, has been disconnected from the' cord circuit per Fig. 2. The transmission circuit in the answering side of the cord circuit, per Fig. 2, is established directly through the normal contacts of relay 230 to the single line repeater in the cord circuit and no longer extends through the transmission loop in the operators position circuit. The calling subscriber and the called subscriber may now communicate directly through the transmission circuits in Figs. l, 2 and 4.

Calling and called subscribers communicate As the calling subscriber at the pay station, per Fig. 1, operates the various keys in his teletypewriter transmitter, the transmitting contacts |25 in his transmitter are positioned in such manner that the transmission circuit extending through a particular transmitting contact is either opened or closed. When a particular contact is closed, the transmission path connecting the calling station with the cord circuit at the central station will be closed. Current will iiow through the transmission conductors in the calling loop and the answering end of the cord. The armature of relay 205 will be actuated to engage with its marking contact. The armature of relay 206 will be held in engagement with its marking contact as current ows through its top winding when batteries of opposite polarities are connected to opposite ends of the calling end of the c ord and the called loop connected in series. Receiving magnets |25, in Fig. 1, and |25 in Fig. 4, will be energized and a marking signal will be recorded at both teletypewriter receivers. If the path through a particular transmitting contact of contacts |26 is open, the transmitting path through the corresponding subscribers loop circuit and the answering end of the cord circuit,- per Fig. 2, cooperating directly therewith Awill be opened. No'current will then iiow through the top or line winding 0f receiving relay 205 in the single line repeater of the cord. The armature o f relay 205 will be actuated under the influence of current through its bottom or biasing winding to engage with its spacing Contact. Batteries of the same polarity will be connected to each end of the corresponding loop through the calling end of the cord and the called line. The armature of relay 206 will be maintained in engagement with its marking contact as the polarity of the current through its bottom or biasing winding is reversed. The teletypewriter receiving magnets in both loops will be deenergized. to record a spacing signal at both the calling and called subscribers stations.

The subscriber recalls The subscriber at either the calling or the called station may recallthe operator at the central station by operating the recall key ||8- in Fig, 1 or H8 in Fig. 4. In response to this, the supervisory lamp associated with the answering end of the cord or with the calling end oi' the cord, depending upon which subscriber re-calls will be ashed intermittently to indicate this condition. The manner in which this is performed is as follows.

It will be assumed that the called subscriber Wishes to recall theoperator. The called subscriber Ywill thereupon operate recallv key |I8'. This opens the circuit through the top loopconductor in Fig. 4 and connects the bottom loop conductor directly to ground.. This in turn breaks the circuit through the top winding of relay |09. The ci-rcuit through the bottom wind-ing of relay |03' is connected at one end to battery |22 and at the other end tov ground connected to the. armatureI of recall key H8'. Under these circumstances, relay |09' will operate. This in turn connectsground to the ring conductor of jack |35 operating relay 252 in the cord circuit, per Fig.. 2, over a path heretofore traced. The operation of relay 252 will establish a-A circuit from. ground through the top inner armature and iront contact of relay 252, top armature and back contact of relay 254',l Winding of relay 253, resistance 235 and the bottom armature and front contact of relay 224 to battery, relay 224, being. operated, operating relay 253. When relay 253 is operated, it locks to ground. throughits bottom inner armature and front contact. Recall key |18 in Fig. 4, is thereupon restored to normal., reestablishing the transmission circuit and releasing relay |09'. Relay 252 is thereuponreleased. A circuiit is now established which may be traced from ground, through interrupter 251V, the top, armature and front contact of relay 253r the bottom.

o-u-terback contact and armature of relay 25-2 through. the lament of lampv 256y to battery. Lamp 256 ashes following the interruptions o the interrupter 251.

Ii the calling subscriber wishes to recall, recall I key ||8 is operated which will cause a circuit corresponding to that described` for the calling end of the cord to operate: in theanswering end of the cord, flashing lamp- 258.

Upon noting the flashing cord lamp, the operator connects her position circuit, Fig. 3., to the cord by operating key 202. Thisl shuntsV relay 253 which releases. extinguishing lamp 256,

Subscriber disconnects In order to disconnect, a train. of signals corresponding to the upper case H may be transmitted` by either the. calling subscriber, the called subscriber or the operator at the central station. The operator at the central station wouldy transmit sucha signal in order to disconnect when the station was being operated on an unattended basis. The reception of the signals corresponding to an upper case H opens contacts |29 in Fig. 1 and |29' in Fig. 4 in the Well-known manner. This intu-rn opens the circuit Which is maintaining relay H9 and relay H9' operated and locked. This circuit was heretoforeV traced. Relay v| i9 andy relay H9 thereupon release. The

release of. relay H9 and of relay H9 restores 75 all. apparatus at the station. to its normal condition when idle. For example, in the calling loop, ground is connected to each of the loop conductors at the pay station. For the top loop conductor a circuit extends from ground on the right-hand` outer back. contact and armature of relay H9, conductor left-hand outer back contact and armature of relay H6, through the windings of magnets H5 and IM, contact till, which is closed while coins are in the coin collect box |00, conductor |.l2 to top loop conductor l |l and thence tothe circuit extending through the tip' oi jack |36 which connects with the tip ot the cord, per Fig. 2. The Circuit for the top conductor extends through the transmission pathin Fig... 2Y which has heretofore been traced and terminates inpositive battery connected to the marking. contact and armature ot relay 206. For the bottom conductor', the circuit extends from ground, through the right-hand outer back contact and armature of relay H9 and the continuity contacts of recall key ||S to a parallel circuit. One branch of said parallel circuitextends through the winding of relay l-l. The other branch extends through` the left-hand inner armature andback contact of relay H6 and contacts i3?. rlhe branches join. and the circuit continues through the contacts of break key |21, teletypewriter transmitting contacts |26, the right-hand outer armature. and` back contact of relay 6, the Winding of the teletypewriter receiving magnet |25, the. bottom loop conductor, variable resistance |24', bottom armature and front contact of relay |08 at the central station, which. relay remains in the operated condition. while the cord circuit is. still connected to jaclf. |33, through. the bottom Winding. of relay H19 and resistance |23 to battery |22.

In tracing the path for each of the loop conductors each was seen to extend through a wind.- ing of relay |19. The effect oi the current in each Winding for this condition, however, is not balanced and the armature of relay |09 will be. actuated. This connects ground to the ring conductor of the cord circuit operating relay 2.2.1 which, in turn, lights lamp 256 as has been heretofore explained. The lighting. of the lamp serves as a disconnectsignal.

A train of signals corresponding to an upper case H impressed upon the receiving magnet |25 of the called subscribers station will result in the opening of contacts |29. This in turn will release relay H9'. This will ground the bottom loop conductor only of the called lin-e at the called central station, operating relay |59. Relay 252 in the. cord, per Fig. 2, will be operated and lam-p 256 will be lighted in a manner which may be understood from the description of the operation of corresponding apparatus in the calling subscribers line, per Fig. 1, and the answering side of the cord circuit, per Fig. 2.

Central station, operator collects coins deposited in com collection` bowv Upon noting the lighted cord lamp, the operator, if her position circuit is not already connected to the cord, will operate key 232 which connects the operators position circuit, per Fig. 3, to the cord circuit, per Fig. 2, in the manner heretofore described. The operator at the central station will now operate coin collection key 334. The operation of this key impresses negative battery 362, of high potential, on a circuit whichl extends through the filament of lamp 363, Winding of coin collect relay 364, front contact and armature of coin collect key 334, back contact and armature of key 333 to conductor 332. The circuit has been traced from this point over the tip circuit of Fig. 2, through the top loop conductor ||2, through the Winding of coin collect magnet ||4 to ground, through the right-hand outer armature and back contact of relay H9, which is released. Magnet |4 controls the mechanism in the coin collection device |00 which is operated to direct the suspended coins into a coin collection chamber at the bottom of the coin collection device. This mechanism is Well known and will not be described herein. Attention is called to the fact that relay 36| is operated upon the operation of key 333 and relay 364 is` The operated upon the operation of key 334. operation of these relays, in turn, lights lamp 365 or 366 to give a visual indication that coins deposited in the collection device |00 are being returned or collected.

It is to be understood that if any condition such as connection to the wrong called party warrants return rather than collection of deposited coins, key 333 may be operated rather than key 334 to return the coin to the calling subscriber.

Central station operator disconnects After the coins have been collected or returned as described above, the central station operator will once more restore key 202 to normal, disconnecting the operators position circuit per Fig. 3 from the particular cord circuit per Fig. 2 with which it has been connected. The operator will then remove the answering plug 20| from jack |36 and the calling plug 204 from jack |36. .i

Relays |08 and |08 are thereupon restored to normal. This, in turn, restores the relays in the subscribers line termination for the calling and called stations to the normal condition when idle.

Relays in the cord circuit are also restored to normal.

Starting an unattended station these circumstances, relay 50 at the called party 4 station remains operated for a suilicient time to permit relay |5|' to operate, over a circuit from the left-hand side of the power source |28 through the winding of relay l 5| the inner front contact and armature of relay |50', and resistance |52 to the right-hand side of the power source |28'. The operation of relay |5| will establish a circuit for the operation of relay |9 which establishes the called station loop and supplies power to operate the teletypewriter mechanism at the called station. The circuit for the operation of relay H9 may be traced from the right-hand side of the power source |28', through the armature and make contact of relay l5 the winding of relay H9', to the left-hand side of the power source |28.

After the unattended station has been started as described above, it is in condition to receive communication signals either from the central station or from a distant calling station.

What is claimed is:

1. In a teletypewriter switching system, a local teletypewriter station, a central teletypewriter switching station, a telegraph circuit connecting said stations, a coin collection device connected Lil) to said circuit at said local station, a telegraph transmitting device at said local station and means responsive to the insertion of a coin in said collection device for operating said transmitting device.

2. In a teletypewriter switching system, a local telegraph station, a central switching station, a telegraph path connecting said stations and means connected to said path responsive to the depositing of a coin in a coin collection device at said local station for recording the denomination of said coin at said central station.

3. In a teletypewriter switching system, a local telegraph station, a central telegraph switching station, a telegraph path connecting said stations, a telegraph transmitter connected to said path at said local station, a telegraph receiver connected to said path at said central station, a coin collection device connected to said path at said local station and means responsive to the insertion of a coin in said collection device for operating said transmitter so as to transmit telegraph code signals characterizing said coin to said receiver.

4. In a teletypewriter switching system, a local telegraph station, a central telegraph switching station, a telegraph path connecting said stations, a coin collection device connected to said path at said local station, and means responsive to the insertion of a coin in said device for recording a permanent record of said insertion,

5. In a teletypewriter switching system, a local telegraph station, a central telegraph switching station, a telegraph path connecting said stations, a coin collection device connected to said path at said local station, a telegraph recording.r device at said central station and means responsive to the insertion of a coin in said collection device for operating said recording devicev so as to provide a permanent record of said insertion.

6. In a teletypewriter switching system, a local teletypewriter station, a central teletypewriter switching station, a telegraph path connecting said stations, a coin collection device connected to said path at said local station, a telegraph signal recording device connected to said path at said central station and means connected to said path responsive to the insertion of a coin in said collection device for transmitting signals characteristic of said coin to said recording device.

7. In a teletypewriter switching system, a local telegraph station, a central telegraph switching station, an operable telegraph path connecting said stations, a multi-coin collection device connected to said path at said local station, a recording device connected to said path at said central station and means responsive to the depositing of any one of a plurality of coins in said collection device for operating a particular transmitting device so as to transmit signals, characterizing the particular coin deposited, to said recording device.

8. In. a telegraph switching system, a local telegraph station, a central telegraph switching station, an operable telegraph path connecting said stations. a coin collection device connected to said path at said local station, a recording device connected to said path at said central station, means in said collection device for depositing therein coins of a plurality of denominations, means responsive to the depositing of said coins for operating a transmitting device individual to each denomination so as to transmit signals characterizing the denomination of the deposited coins to said recording device.

9. In a teletypewriter switching system, a telegraphv transmitter, a telegraph receiver, a telegraph path connecting said transmitter andsaid receiver; a coin collection device connected to said path and means also connected to saidV path for preventing the operation of said path unless a coin has been deposited. in said collection device and a record thereof has been recorded by said receiver.

10. In a teletypewriter switching system, a local teletypewriter pay station, a central teletypewriter switching station, a telegraph circuit connecting said stations, a teletypewriterl transmitter connected to said circuit at said pay station, means for connecting an operators position circuittosaidK telegraph circuit at said central station, means in said` circuits for designating an amount of money to be deposited in a coin collection device at said pay station and means at said central station for recording the amount deposited.

11. In a teletypewriter switching system, a teletypewriter pay station, a central teletypewriter switching station, a telegraph circuit connecting said stations, a coin collection device connected to said circuit at said pay station, means responsive to the depositing of a coin in said collection device for signalingY an operator at said central station, means at said central station for extending said telegraph circuit toward a called station, means in said circuits for designating an amount of money to be deposited in said collection device before communication may proceed, means for preventing communication from proceeding until said amount has been deposited in said device and means responsive to the depositing of coins in said device for recording the amount deposited at said central station.

12. In a teletypewriter switching system, a teletypewriter transmitting station, a teletypewriter receiving station, means for flexibly interconnecting said stations and means for preventing communication between said stations until a permanent record of a charge for such communication has been made by a recording device oonnected to said circuit.

13. In a teletypewriter switching system, a calling teletypewriter station, a called teletypewriter station, means for establishing temporarily a continuous telegraph circuit between said stations, means for connecting atarii charge recorder temporarily in said path and means for providing a permanent record of the charge for communication between said stations.

14. In a teletypewriter switching system, a telegraph central switching station, means for interconnecting calling teletypewriter stations with called teletypewriter stations through said central station, means at said central station for temporarily connecting a recording device to said connections as said connections are established for recording the tarii to be charged for such connections.

15. In a teletypewriter switching system, a central telegraph switching station intermediate a calling and called station, means in said central station for establishing connections between said calling and called stations, means at said central station for informing a subscriber at said calling station of a charge to be prepaid before communication may proceed with said called station and means for recording the prepayment of said charge.

16. In a teletypewriter switching system, in

combination a teletypewriter central switching station, a subscribers local teletypewriter station, an operable telegraph path connecting said stations, means in said path, responsive to the depositingv of a coin in a coin collection devicel con,- nected to said path at said local station, for con-1 A trolling communication over said path and means, connected to said path remote from said local station,v for starting a teletypewriter machine at said local station.

17. In a teletypewriter switching system, in combination, a teletypewriter central switching station, a subscribers local teletypewriter station, an operable telegraph path connecting said station, means in said path, responsive to the depositing of a coin in a coin collection device connected to said path at said local station, for controlling communication over said path and means, connected to said path, remote from said local station for stopping a teletypewriter machine at said local station.

18. In a teletypewriter switching system, a tele-l graph line, a coin collection device connected thereto and means responsive to the depositing of a coin of a particular denomination in said device for transmitting telegraph code signals characterizing its denomination.

19. In a teletypewriter switching system, a telegraph line, a coin collection device and a telegraph code signal transmitter both connected to said line and means also connected to said line, responsive to the depositing of a coinV in said device, for operating said transmitter so as to transmit telegraph code signals over said line..

20. In a teletypewriter switching system a transmitter arranged to transmit baudot telcgraph code signals, a coin collection device and means responsive to the depositing of a coin of a particular denomination in said device for operating said transmitter so as to transmit telegraph code signals characterizing the denomination of said coin.

21. In a teletypewriter switching system, a baudot code telegraph signal transmitter and coin-operated control means connected to said transmitter for generating baudot code telegraph signals characterizing the denomination of a coin.

22. A system for transmission of permutation code comprising a channel of transmission, permutation code emitting means for impressing upon said channel Vmessage codes, coin operated means, and means controlled thereby for emitting upon said channel codes indicative of the operation of said coin operated means.

23. A permutation code transmitter in combination with a coin controlled circuit changer and means operable by control of said changer by a coin to cause said transmitter to send a permutation code.

24. A permutation code transmitter in com bination with coin actuatable circuit changing means and means selectively operated by coins of different nature to selectively actuate said transmitter.

25. A telegraph system comprising a message transmitter of coded impulses and a supplemental transmitter in combination with check controlled means for actuating the supplemental transmitter and interconnections whereby said transmitters may be operated at diierent times without interference one with the other.

WILMARTH Y. LANG. FRED J. SINGER.

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