US1765619A - Party-line telephone system - Google Patents

Description

June 24, 1930. N. H. SAUNDERS PARTY LINE TELEPHONE SYSTEM 4 Sheets-Shet 1 Filed July 2. 1928 l L 1lk N% as MnMnn n n nnn U MN 7 1m Nur'man H. Saunders June 24, 1930.

N. H, SAUNDERS PARTY LINE TELEPHONE SYSTEM Filed July 2, 192a 4 Sheets-Sheet 2 In an ur Norman H. Saunders M4 044 Hfi June 24, 1930.

N. H. SAUNDERS PARTY LINE TELEPHONE SYSTEM Filed July 2 1928 4 Shei-s-Sheets Norman H. Saunders June 24, 1930.

N. H. SAUNDERS 1,765,619 PARTY LINE TELEPHONE SYSTEM Filed July 2. 1928 4 Sheets-Sheet 4 Elfin HF Nari-nan H. Saunders latented June 24, 1930 UNITED STATES PATENT Friar.

NORMAN H. SAUNDERS, OF IQOlvIEVJOOD', ILLINOIS, ASSIG-NOR T0 RESERVE HOLDING COMPANY, OF KANSAS CZTY, MISSOURI, A. CORPORATION OF DELAWARE PARTY-LINE TELEPHONE SYSTEM Application filed July 2, 1928.

The present invention relates in general to automatic telephone systems but is more particularly concerned with automatic telephone system of the type which are gener-,

ally installed in small towns or villages, these systems being commonly known as mixed service systems, or community automatic exchanges; and the object of the invention, briefly stated, is the provision of new and improved means for signaling the subscribers on rural or party lines.

One of the features of the invention relates to the provision of a common code interrupter for controlling the application of ringing current to the called line.

Another feature of the invention relates to the circuit arrangements by means of which a code selector is arranged so that it will transmit either a one ring or a two ring code, that is, it will transmit either one series or group of ringing current impulses or two separate series or groups of ringing current impulses.

Another feature of the invention relates to the pick-up arrangement for starting the ring and for controlling the changeover from one of the minor switches of the code selector to the other minor switch in order to transmit a two ring code.

Other features relate to the improved connector switches and the improved reverting call switches for use in a system of this type.

These and other features of the invention will be apparent from the following detailed description of the invention.

Referring now to the drawings, comprising Figs. 1 to 5, inclusive, there is shown by means of the usual circuit diagrams sufficient of the apparatus in an automatic telephone system to enable the invention to be readily understood.

In Fig. 1 there is shown at A one of the ordinary common battery automatic substations on a party line.

Each party line has a rotary line switch, such as C, individual thereto. The line switch O is of the well known rotary type with its wipers moving in a forward direction only and having no normal position.

Serial No. 289,739.

The line switch O has the function of extending the line of sub-station A, when the receiver is removed, to a trunk line terminating in an idle mixed service connector, such as indicated by the reference character H.

The connectors, such as H, are of the usual Strowger vertical and rotary type, and have access to individual lines, party lines, trunk lines, and reverting-call switches.

In Fig. 2v is shown a code selector OS which is permanently associated with the connector H shown in Fig. 1. The code selector comprises a number of relays and two minor switches, S and S, which are simple rotary switches adapted to be rotated in response to impulses and restored to normal by the operation of their respective release magnets. Each connector switch has a similar code selector associated therewith.

In Fig. 3 is shown a code interrupter G1 which is common to all of the code selectors and connectors in the exchange. The code interrupter comprises a plurality of relays and a position rotary step-by-step sequence switch mechanism. The ratchet and pawl mechanism, as well as the motor magnet of the code interrupter is diagrammatically illustrated in'the dotted rectangle of Fig. 8. On the same shaft with. the ratchet are live circular cams having spaced notches therein. Associated with each cam there is provided a brush which rides on top of the circular cam and which drops into the spaced notches at certain positions of the interrupter to close its asso ciated contact set. Only the number 5 cam and brush set is illustrated near the top in the dotted rectangle, such cam being in normal position, or the 25th position of the code interrupter. Directly below this illustration, the cam and brush sets, numbers 1 to 5, inclusive, are diagrammatically illustrated by the correspondingly numbered brush sets. The numbers to the right of each set indicates the positions of the interrupter switch in which each brush drops into the spaced notches of its associated cam.

In Fig. 4 is shown one of the reverting call switches to which the connectors, such as H, have access. The reverting call switches comprise a plurality of relays and two minor switches S and S which are similar to the minor switches shown. in the code selector. The code interrupter in Fig. 3 is also common to the reverting call switches.

In Fig. 4 there is also shown one of the rural lines to which the connectors, such as connectors H, have access. Sub-station A is one of the local battery magneto sub-stations on the rural line. Associated with each magneto line is an individual repeater, such as R, which comprises a repeating coil and two relays. terminates in a rotary line switch, such as C, which is similar in all respects to the rotary line switch C shown in Fig. 1.

Fig. 5, shown on the same sheet as Fig. 1, shows the well known method of wiring the connector test bank contacts for trunk hunting connectors. In Fig. 5 only the test contacts of the tenth level accessible to the test wipers of the connector H are shown.

The rural lines are local battery magneto lines and in case a subscriber on a line wishes to call another subscriber on the same line, the calling subscriber will ring, by means or" his hand generator, the code of the called subscriber without the necessity of operating the exchange equipment. The common battery party lines, or .town lines, are not equipped with magnetos and therefore the reverting call switches, such as the one shown in Fig. 4, are used when a common battery subscriber wishes to call another subscriber on his own line.

The connectors, such as H, are arranged so that they can select an idle trunk line out of a group of trunk lines extending to a distant automatic exchange, but as such connections are not considered a part of this invention no such trunklines are shown or described.

Having briefly set forth and described the apparatus shown in the drawings, the op eration of the system will now be described. For this purpose it will be assumed that the common battery subscriber A desires to call the subscriber A on the rural line indicated in Fig. 4. Let it be further assumed that the number of the rural line is 23 and that the code call for station A is 54. In this case the calling subscriber must dial the number 2354.

\Vhen the receiver is removed at the calling sub-station a circuit is completed over the conductors 11 and 12 for the line relay 15 of the line switch C. Upon energizing, relay 15 at armature 20 closes a circuit through the winding of the switching relay Each magneto line also.

14 and stepping magnet 16 in series, and at its armature 21 connects test Wiper 26 to the above circuit at a point midway between the switching relay and the stepping magnet. The operation now depends upon whether the trunk line with which the line switch wipers are associated is busy or idle. It the trunk line is busy there is a ground potential upon the test contact with which the test wiper 26 is in engagement; the switching relay 14 is short circuited, and the stepping magnet 16, which interrupts its own circuit, is operated in the manner of a buzzer to stop the switch wipers to an idle trunk line. Assuming that the connector H is the first idle connector encountered, when the line swi ch wipers reach this connector the switching relay 1 1, being no longe short circuited, energizes in series with stepping magnet 16. Stepping magnet 16 is not operated in this circuit on account of the high resistance of the switching relay. Switching relay 14-, upon energizing, disconnects the test. wiper 26 from the above described test circuit and connects the wiper to its own upper terminal at armature 18, and

at its armatures 17 and 19 disconnects the line conductors 11 and 12 from the winding of relay 15 and ground, respectively, and extends them by way of wipers 25 and 27 and bank contacts 28 and 30 to line relay 36 oi the connector H. The line relay 3 6 and the release relay 37 oi the connector H are now energized in the usual manner and the latter relay grounds the release trunk conductor extending baclr to the test contact 29 in order to establish a holding circuit for the switching relay 1% of line switch C. This operation is well understood ant need not be explained further.

Release relay 37, upon energizing, at armature 6O grounds the release-trunk conductor 32 as previously described; at armature 62 and working contact prepares the impulsing circuit and at its resting contact opens a point in the circuit of the release magnet 4'2; and at armature 61 closes an energizing circuit I the combined changeover and ring cut-oii relay 39 as follows: ground by way of armature 61, normally closed off-normal springs 57, and lower winding oi relay to battery. Relay 39 upon energizing, armature 69 prepares a locking circuit for itself and atarmature 68 and its working contact prepares the inipulsing circuit for the vertical magnet 45.

The calling subscriber may now operate his calling device in accordance with the first digit in the desired numbe Each time the line circuit is intcrrup -v the calling device, line relay 3S falls bacli and closes the circuit of vertical magnet 45 in series with slow acting series relay 38. The

impulsing circuit to the vertical magnet tends by way of grounded armature 52, ar-

mature 59 and its resting contact, armature 62 and its working contact, armature 75, winding of relay 38, armature 68 and its working contact, and winding of vertical magnet 45 to battery. The vertical .i'nagnet operates and steps the switch wipers in the well known manner t the desired level. Re-

lay 38 energizes in series with the vertical magnet and at armature 65 and its working contact completes the locking circuit for relay 39 so that the latter relay will not release "hen its initial energizing circuit is opened by the operation of the off-normal springs 57. In addition to the above, armature 65 also closes a circuit for energizing relay This relay, however, pretorms no usei'ul function at this time. Soon after the last vertical impulse slow acting relay 38 deenergizes thereby permitting the release of relays 39 and 43. Relay 39, upon deenergizing, at armature 68 and its resting contact prepares the impulsing circuit to the rotary magnet.

In response to the dialing of the second digit of the called number, rotary magnet 46 rotates the wipers 95 to 98, inclusive, into engagement with contacts 200 to 203, inchn sive. The iinpulsing circuit through the retary magnet 46 extends by way of grounded armature 52, impulsin' armature 59 and its resting contact, armature 62 and its working Contact, armature 7 5 and its resting contact, winding of slow acting relay 38, armature 68 and its resting contact, armature 86 and its resting contact, and winding of rotary magnet 46 to battery. Slow acting relay 38 is energized in series with the rotary mag net and remains energized during the impulsing cried even though relay 41 operates its armature springs as a result of the test wiper 97 encountering grounded contacts. At armature 64 relay 38 maintains the rotary impulsing circuit and at armature 65 again completes the circuit for energizing relay 43.

The operation now depends upon whether the called line is busy or idle. it it busy, ground is present on test contact 201 and busy relay 41, therefore, energizes over the following circuit; from grounded testcontact 201, test wiper 97, armature 82 and its working contact, armature 88, and winding of busy relay 41 to battery.

When slow acting relay 38 deenergizes after the rotary impulses, said relay at armature 65 opens the circuit of relay 43. Relay 43, however, is slightly slow to deenergize because its upper winding is short circuited by armature 76 and its working contact. Relay 43 deenergizes after an interval and at the normally closed springs controlled by armature 82 completes a locking circuit for busy relay 41 as follows: grounded armature 61, armature 74 and its working contact, normally closed springs controlled by armature 82, armature 88, and

winding of busy relay 41 to battery. Busy relay 41, upon energizing, at armature 73 prepares a circuit to the stepping relay 42 which at this time is without etlect; at armature 74 and its resting contact opens the circuit of the switching relay 44 and at its working contact closes the previously mentioned locking circuit for the busy relay; at armature 75 opens the impulsing circuit; and at armature 77 connects the busy signaling machine to the lower line conductor. This operation gives the calling subscriber an audible busy signal to inform him that the called line is busy, and therefore he will hear the signal and replace his receiver.

It will now be assumed, however, that the called line is idle when the connector H is operated. Under these circumstances as soon as slow acting relay 38 deenergizes, upon completion of the rotary movement, relay 43 deenergizes and completes the following circuit for switching relay 44: from ground by way of armature 61, armature 7'4 and its resting contact, upper winning of switching relay 44, resting contact of armature 82 and said armature, wioer 97, bank contact 201, conductor 205, switching relay 208 of the called line switch, and through the winding of the stepping magnet 209 to battery. Relays 44 and 208 energize over the above traced circuit and relay 208, upon energizing, removes the line relay bridge at th line switch C in the well known manner. Switching relay 44, upon energizing, prepares the talking circuit at armatures 83 and 91; at armature 85 prepares a locking circuit for relays 110 and 112 in the code selector SS, Fig. 2; at armature 86 transfers the impulsin g circuit from the rotary in gnet 46 to the motor magnet 108 of the hrst minor switch S in the cod selector CS; at armature 87 connects guarding ground to test wiper 97 and test contact 201; at" armature 88 opens the circuit of bus relay 41; at armature prepared a locking circuit for the ring cut-off of relay 39; and at armature 89 completes a locking circuit for itself which may be traced as follows: ground by way of release trunk conductor 32, armature 50 and its resting contact, armature 89, and winding of switching relay 44 to battery.

The calling subscriber may now operate his calling device in accordance with the first code digit, or the digit 5. A series of impulses, as before are transmitted over th impulsing circuit by way of armature 86 and its working contact, conductor 103, armature 125, armature 130 its resting contact, and winding of the motor magnet 108 of minor switch S of the code selector CS to battery. Relays 38 and 43 of the connector H are again operated while the motor magnet 108 of the switch S operates the wipers 115 and 116 into engagement with llh) the fifth set of bank contacts. lVhen the slow acting relay 38 deenergizes shortly after the first series of code impulses, a circuit may be traced by-way of armature and its resting contact for energizing relay 112 of the code switch by way of conductor 101 and ofi normal springs 117 which are closed as soonas the wipers 115 and 116 are moved oil-normal. Relay 112, upon energizing, at armature 126 prepares a circuit for the release magnet 107 of the switch S; at armature 127 prepares a point in the circuit for grounding the interrupter start lead 132; at armature 128 prepares a point in the locking circuit for relay 110; at armature 129 completes a locking circuit for itself; and at armature 130 transfers the impulsing lead 103 from motor magnet 108 of the sswitch S to motor magnet 106 of the switch In response to the calling of the last code digit, relays 38 and 43 in the connector H and motor magnet 106 operate. By the operation of motor magnet 106 wiper 113 is moved into engagement with its fourth bank contact. When slow acting relay 38 deenergizes shortly after the last code impulse, a circuit may be traced from grounded armature 65 for energizing relay 111 by way of conductor 101 and off-normal springs 114 of the switch S which are closed as soon as wiper 113 is moved oil-normal. Relay 111, upon energizing, at armature 122 prepares a point in the circuit for release magnet 105 of the switch S; at armature 123 connects ground to interrupter start conductor 132; at armature 124 connects relay 110 to pick up conductor 134; and at armature 125 opens the impulsing circuit.

As soon as the common interrupter start conductor 132 is grounded relay 207 of the code interrupter is energized over its lower winding. Relay 207, upon energizing, at armature 226 prepares a circuit for grounding the common pick-up conductor 134; armature 227 closes a locking circuit for itself by way of armature 221; at multipled armatures 230 grounds the cam and brush sets numbers 1 to 5, inclusive; armature 231 prepares a circuit for connecting common lead 138 to the number 5 cam and brush set; and at armature 228 closes a circuit 101' energizing interrupter relay 205 in order to startthe interrupter mechanism.

Relays 205 and 206 are slow to energize and act as interrupter relays for controlling the operation of motor magnet 208 of the interrupter mechanism, Relay 205, upon energizing, at armature 224 completes a circuit for energizing relay 206. Relay 206 at armature 225 closes a circuit for energizing motor magnet 208. Motor magnet 208, upon energizing, operates its associated armature and pawl mechanism. and closes its associated spring contacts 232 near the end of its armature stroke. By the operation of springs 232 relay 205 is shunted by ground whereupon said relay slowly deenergizes. When relay 205 is fully deenergized the circuit of relay 206 is opened at armature springs 224 and said relay slowly deenergizes due to the short circuit around its winding controlled by armature 224. As soon as relay 206 deenergizes, armature 225 opens the circuit of motor magnet 208 thereby releasing its armature. By the release of its armature motor magnet 203 causes the pawl and ratchet mechanism to move cams numbers 1 to 5, inclusive, from their 25th position, or normal position, to their first position. As soon as springs 232 open, relay 205 again slowly energizes and again completes the circuit for energizing relay 206. Relay 206 again operates the motor magnet 208. This sequence of operation just described continues until ground is removed from the common interrupter start lead 132 and until the code interrupter has been returned to its normal or 25th position.

In position 1 of the code interrupter a circuit may be traced ior energizing relay 200 as follows: ground by way of the grounded multipled armatures 230, number 4 cam and brush set, armature 220 and its resting contact, armature 216 and its resing contact, and winding of relay 200 to battery. Relay 200, upon energizing, at armature 213 grounds the common reverse lead 133 and in addition grounds the common pick-up lead 134 by way 01 armatures 226 and 215; and at armature 214 prepares a circuit for relay 201 which relay, however, will not energize at this time because of the shunt circuit around it.

W hen the pick-up lead 134 is grounded, pick-up relay 110 of the code selector energizes and completes a locking circuit for itself by way of armature 121 and armature 128 to the lock ground conductor 104. At armature 119 relay 110 prepares a circuit to the rin ing lead 102; and at armature 120 completes a circuit for energizing the reverse relay 109 by way of the grounded reverse lead 133. The reverse relay 109, upon energizing, at armature 118 connects the ringing lead conductor 102 to wiper 115 which, it will be remembered, is in engagement with conductor 139.

In position 2 of the code interrupter ground is removed from the number 4 code interrupter contact whereupon the short circuit around relay 201 is opened and said relay then ener izes over the following circuit: ground by way of armature 227, armature 219 and its resting contact, winding of relay 201, armature 214, and winding of relay 200 to battery. Relays 200 and 201 are maintained energized over the above tracer circuit. Relay 2011, upon energizing, at

armature 215 removes ground from the pickup conductor 134 thereby preventing any other code selector which may later on be operated from transmitting code ringing impulses at the wrong time. At armature 216 relay 201 opens the ori ial energizing circuit o1 relay 200 and prepares a circ" t for encz ling relay 202. Wh en the number 5 cam and brush set is closed in position 2, a ground impulse may be traced by way of armature 230, number 5 brush set, conductor 139, fifth bank contact and wiper 115 of switch S, working contact of armature 118 and said armature, armature 119, and ringing lead 102 to ringing relay 40 and battery in the c nnector H.

In position 3 of the code interrupter control conductor 233 is again grounded by the number 4 cam and brush set whereupon relay 202 energizes by way of armaturcs 220 and 216. Relay 202, upon energizing, at armature 217 prepares an energizing circuit "for relay 203 but said relay does not energize until ground is removed from the control conductor 233 when the code interrupter reaches position 12. At armature 218 rolay 202 connects the common conductor 138 to the number 5 cam and brush set.

The code interrupter continues to operate I from this point on in the same manner ust described, ground impulses being sent to ringing relay 40 in the connector in positions 2, 4, 5, 8, and 10 of the code interrupter. In positions 3, 5, 7 9 and 11 the ground circuit to ringing relay 40 is 1nterrupted.

-As soon as the code interrupter reaches position 12 ground is removed from the control conductor thereby permitting relay 203 to energize over the following circuit: grounded armature 227, armature 222 and its restin contact, upper winding relay 203, armature 217, and winding of relay 202 to battery. Relays 202 and 203 are maintained energized over the bove traced cir cuit. Relay 203, upon energizing, at armature 219 opens the circuit of relays 200 and 201 whereupon said relays deenergize; at armature 220 and its resting contact opens the initial energizing ci cuit of relay 200 so that the latter relay will not energize when the control conductor 233 is again grounded; and at armature 220 and its working contacts prepares an energizing circuit for relay 204. Relay 200, upon denergizing, at armature 213 removes ground from the reverse lead 133 whereupon relay 109 in the code selector deenergizes. Relay 109, upon deen ergizing, at armature 118 switches the ringing lead 102 from wiper 115 to wiper 113.

Since wiper 113 is in en agement with the fourth bank contact whic is connected to common conduct r 138, grounded impulses may be traced in positions 14, 16,18, and 20 of the code interrupter for operating ringing relay 40 as follows: ground by way of armature 230, number 5 cam and brush set closed in positions 14, 16, 18, 20, and 22, armature 231, armature 218, conductor 138, fourth bank contact and wiper 113 of switch S, resting contact of armature 118 and said armature, armature 119, ringing lead 102, to relay 40 and battery. In position 15, 17, 19 and 21 these grounded impulses are interrupted by the code interrupter.

In positions 21 to 24, inclusive, ground is again connected by the number 4 cam and brush set to control lead 233 whereupon relay 204 energizes by way of armature 220. At armature 223 relay 204 closes a circuit for maintaining relay 203 energized; at armature 222 opens the initial energizing circuit of relay 203 and the circuit of relay 202 whereupon the latter relay deenergizes; and at armature 221 opens the locking circuit of relay 207 which, however, is maintained energized by ground on control lead 233 in positions 21 to 24 of the code interrupter.

Relay 202, upon deenergizing, at armature 218 opens the circuit to the number 5 cam and brush set so that the last ground impulse will not be sent over conductor 138 when the cam reaches position 22. In case, however, wiper 113 was in engagement with the fifth bank contact and conductor 139, a ground impulse would be sent for operating the ringing relay in the connector.

Before the code interrupter reaches position 25, ground is removed by the number 4 cam and brush set from the control lead 233 whereupon relays 207, 204 and then relay 203 deenergize. Relay 207 releases provided ground, in the mean time, has been removed from the interrupter start lead 132. Ground is removed from the interrupter start lead 132 when the called man answers or when the calling party abandons the call in a manner which will be described hereinafter. In case ground has not been removed from the interrupter start lead 132 relay 207 is maintained energized over its lower winding and the code interrupter continues to operate in the same manner as just described.

Returning to the connector in Fig. 1, each time ringing lead 102 is grounded ringing relay 40 energizes. Each time ringing relay 40 energizes a circuit may be traced for energizing relay 214 of the repeater B, Fig. 4, as follows: ground by way of the working contact of armature 71 and said armature, resting contact of armature 66 and said armature, armature 83, wiper 95, bank contact 200, conductor 204, armature 215 and its resting contact, and winding relay 214 to battery. Relay 214, upon energizing, at armature 216 connects ground to the upper talking conductor 218 and also disconnects the right hand winding of the repeating coil; and at armature 217 disconnects the right windings of repeating coil from ductor 219 at its resting contact and at its working contact connects the lower talking conductor 219 to conductor 206. A circuit may now be traced for ringing the called subscriber as follows: from the ringing machine by way 01"" the working contact of armature T2 and said armature, resting contact of armature 70 and said armature, armature 91, wiper 98, bank contact 203, conductor 206, workin contact and armature 21?, con ductor 219, through all of the ringers on the rural line, conductor 218, and armature 211; and its working contact to ground. Ring backetone is transmitted to the calling sub scriber in the well known manner each time relay connects the generator to armature 72, the ring-back-toneextending by way of ring-back-condenser RBC and lower talkin conductor 31.

When the called party answers during the silent period, or non-ring period, a circuit from ground is closed by way of the norn'ially closed impulse springs on the calling device, through the switch hook springs, and through the two ringer coils in parallel to conductors 218 and 219, and thence by way of armatures 216 and 217, upper and lower right hand windings of the repeating coil, and winding relay 213 to battery, it being understood that relay 214 is energized only during the ringing period. Relay 213, upon energizing, over the above traced circuit, at

armature 215 closes a bridge including the left hand windings of the repeating coil across the conductors 204C and 206. Respoir sive to the closure of this bridge, ring cutoff relay 39 energizes over the following ci cuit; ground by way of the resting contact of armature 72 and said armature, over the previously traced ringing circuit including at this time the left hand windings of the repeatin coil and the armature 2 condue-tor 2041, bank contact 200, wiper 9e, mature 83, armature 66 and lts'resting con tact, armature 71 and its resting contact,

and through the upper winding of ring-cutoff relay to battery. Ring cnt-el'l re ay 39, upon energizing, at armature 67, and its resting contact disconnects ground from th lock conductor 10 1 and at its working con tact connects ground to release lead 100; armature 69 completes a locking circuit for self; and at armatures 66 and connects the upper and lower talking conductors to the switch wipers '95 and 98. respectively;

and at the same time opening the ring. g circuit. The locking circuit for the ring cut-ofi-relay 39 may be traced as follows: ground by way of armature 60 and its worl; ing contact, armature 50 and its resting con tact, working contact of armature and said armature, armature 69, and lower windfor extending other calls.

ing of relay 39 to battery. The talking circuit may be traced over the heavy talking conductors in the usual manner.

When ground is removed from the lock conductor 10% relay 110 in the code selector deenergizes but relay 112 is held energized over its lower winding by way of oil-normal springs 11? and conductor 101. hen the called party answers and ground is connected to release-lead the release magnets and 107 of the switches S and S, respectively, energize and restore the switch wipers 113, 115, and 116 to normal position. As soon as the switches S and S are returned to their normal position the off-nor- Inal springs 117 and 114 are opened thereby causing the release of relays 111 and 112. By the release of relays 111 and 112 ground is removed from the interrupter start-lead 132. The code switch CS is now in normal position.

Returning now to the connector the back brid e relay 35 is energized over the bridge loop at the repeater and said relay reverses the current new extendingover conductors and 31 for metering or for supervisory purposes.

When the called subscriber A replaces his receiver after the conversation, relay 213 deenergizes and opens the bridge circuit at the repeater which in turn causes the bacle bridge relay 35 to deenergize. When the calling subscriber A replaces his receiver the line and elease relays 36 and 37 deenergize. lit armature 60 release relay grounds the releasedead 100 so that the code selector may be released in the manner previously described 'n case the called man did not answer. At armature 62 release relay closes a circuit for energizing the release magnet 41!".

in the well known manner. By the removal of ground from. the release-trunk conductor by armature 60 line switch C is also returned to its normal position. The removal f ground from release-trunk conductor 32 at armature 60 also opens the locking circuits of relays 44 and whereupon said rclays deenergize. At armature 61 release lay also disconnects ground from test wiper 97 thereby permitting the called line switch C to release in eln well known manner. All of the apparatusinvolved in setting up the conn ction between an scribers A and A is now in normal l2QSl-uul1 and may be used :laving described the operation of the apparatus involved in a connection between a common battery subscriber a: l ru il local battery subscriber, a description now be given of the operation of the asp-a ratus involved in a connection when a common battery subscriber calls another party on his own line. F or this purpose it will By the operation of the release magnet connector ii is returned to normal. position code ring digits are 2 and 3 the calling sub scriber will dial the digits 0, 1, 2, and S.

Eesoonsive to dialin the dl it O the conhector H is operated in the manner previously described opposite the 0 or tenth level. In this case, however, the shaft-controlled springs 92 are operated when the connector wipers are raised opposite the 0 level, or the level in which the trunks to the reverting call switches terminate. Soon after the last vertical impulse, relay 38 deenergizes and permits relay 39 to deencrgize and transfer the impulsing circuit from the vertical magnet 45 to the rotary magnet 46.

Since the first four trunk lines in the 0 level are connected to reverting call switches the calling subscriber will dial the digit 1 and the connector will rotate in the same manner as previously described into engage ment with the first bank contact in the tenth level or into engagement with the bank contacts terminating the trunk to the first reverting call switch. Assuming that the first reverting call switch is busy, there will be a ground potential on both of the test contacts with which wipers 96 and 97 are in engagemcnt. Accordingly, circuit will be closed from the grounded test contact by way of wiper 97 and armatures 82 and 88 to the busy relay 41, it being remembered that relay 43 is held energized by the relay 38. Busy relay 41, upon energizing, at armature 74 and its resting contact opens the circuit of the switching relay 44 and at its working contact orepares a locking circuit for itself; at armature 75 opens the impulsing circuit; at armature 76 short circuits the upper winding oi relay 43 to render said relay slow to release, and at armature 73 completes an energizing circuit for stepping relay 42 in case cst wiper 96 is in engagement with a grounded test contact. The circuit for energizing relay 42 may be traced as follows: from ground by way of the bank contact with which wiper 96 is in engagement, armature 81 and its working contact, armature 63, armature 73, interrupter springs of the rotary magnet 46, and winding stepping lay 42 to battery. At armature 80, relay 42 connects ground to the lower winding of relay 43 in order to maintain said relay in energized position; at armature 79 completes a locking circuit for itself by way of grounded armature 61 and interrupter springs of the rotary magnet; and at armature 78 completes an energizing circuit for the rotary magnet 46 by way of grounded armature 61. The rotary magnet now energizes to rotate the wipers 95 and 98, hr clusive, into engagement with the next set of contacts in the same level. Near the end of its stroke rotary magnet 46 opens its interrupter springs thereby interrupting the circuit of the stepping relay 42 whereupon the relay deenergizes. Stepping relay 42, upon denergizing, opens the circuit of the rotary magnet whereupon the rotary magnet deenergizes. In case the test bank contacts with which the wipers 96 and 97 are now in engagement are grounded the busy relay will be maintained energized and the stepping relay 42 will againenergize and operate the rotary magnet to rotate the wipers another step. This cycle of operation continues until the wipers 96 and 97 encounter an idle reverting call switch trunk or until the last set of contacts associated with the last reverting call switch trunk is encountered. In case all of the reverting call switches are busy the connector H will rotate in the manner just described into engagement with the last set of contacts whereupon the busy relay 41 alone is energized, since the test bank contacts 301 and 302, Fig. 5, have no multiple connection. The busy relay then transmits the busy tone to the calling subscriber in the well known manner.

Assuming, however, that the reverting call switch BUS, shown in Fig. 4, is the first idle reverting call switch then when the wipers 96 and 97 encounter the test contacts 302 and 301 there will be no ground potentials thereon and the busy relay 41 will not be energized. Accordingly, when the busy relay 4-1 is not energized the upper winding of relay 43 is 'no longer short circuit-ed and said relay quickly falls back and establishes a circuit for the switching relay 44. The circuit for energizing switching relay 44 may be traced as follows: ground by way of armature 61, armature 74 and its resting contact, upper winding switching relay 44, resting contact of armature 62 and said armature, wiper 97, bank contact 301, conductor 305, and through resistance 321 to battery. Switching relay 44, upon energizing, at armature 85 completes a circuit for energizing switching-through relay 34; at armature 86 opens the impulsing circuit to the rotary magnet; at armature 87 connects ground to test contact 301 by way of wipor 97; at armature 88 opens the circuit of the busy relay 41; and at armature 89 completes a locking circuit for itself which extends by way of grounded armature 60 and armature 50. The circuit for energizing switching through relay 34 may be traced as follows: ground by way of armature 67 and its resting contact, armature 85, shaft controlled spring 92 and its working and their respective working contacts switche the conductors 33 and 31 straight througn to the wipers 95 and 98; at armature 50 and its working contact opens the locking circuit of switching relay 44 but said relay does not immediately deenergize because its upper winding is short circuited by ground on the release-trunk conductor 32 and by ground at armature 61; at the working contact of armature 50 connects the two release- trunk conductors 32 and 305 together by way of wiper 97; armature 51 completes a locking circuit for itself to grounded release-trunk conductor 2; and at armature 52 removes the ground connection thereat so that the connector H will not release at this time. The line and release relays 36 and 37 deenergize in the usual manner but do not cause the release of the switch because in the meantime ground is connected to the release trunk conductors 305 and 32 to maintain relay and lineswitcl'i C in operated position. After an interval switching relay 44 deenergizes. All the relays in the connector H with the exception of switching-through relay 34are now in deenergized or normal position.

lVhen the switching-through relay 34- of connector H switches the talking conductors straight through, line relay 308 of the reverting call switch RC3, in Fig. 4, energizes over the calling subscribers loop and causes the energization of release relay 309. Re=

lease relay 309, upon energizing, at armature 323 connects ground to the releasetrunk conductor 3305 thereby maintaining switching through relay and line switch C in operated position. At armature 329 relay 309 prepares the impulsing circuit to the motor magnets 317 and 319; and at armature 330 opens the release circuit for the release magnets 318 and 320.

The calling subscriber may now dial the first code digit, or. the digit 2. The line relay 303 accorfigiy sends two impulses; for operating motor magnet 317 to cause the switch wi ers and 347 to exc se into engagement'with the second ot bank contacts. The circuit for the motor magnet may be traced as follows: ground by way are 327 its resting contact,

mature and i l 34.3 and i tact, and w battery. Slow relay atod in pa h n otor nuignet said relay, upon oner at armature removes ground ii conductor 360. loiiortly atter the first series of code impulses, slow acting relay 312 deenergizes and connects ground to conductor 360 thereby closing an energizing circuit throng the upper winding of relay 316 by wy Oil-ilOflllZtl contact Relay energizing, at armature 343 transfers impulsing circuit from motor nu to motor magnet 319; armature 314 completes the locking circuit through its lower winding by way of armatures and 330; and at armature 345 prepares release the circuit for release magnet 318 of the switch S The calling subscriber will now dial the second code digit, or the digit 3. Accordingy, three impulses are sent over the im pulsing circuit for operating motor magnet 319 of the switch S Motor magnet 319 steps its Wiper 349 into en agement with the third bank contact. Slow acting relay 312 again energized and again removes ground from conductor 360. Shortly after the second series of code impulses havebeen sent, relay 312 decnergizes and connects ground to conductor 360 thereby completing an energizing circuit for relay 310 by way of off-normal springs 350 of switch S Relay 310, upon energizing, at armature 331 opens the impulsing circuit at its resting contact and at its working contact prepares a circuit for relay 307; and at armature 332 prepares the release circuit for the release magnet 320.

After dialing the last code impulse the calling subscriber will replace his receiver thereby interrupting the circuit of line relay 308 of thereverting call switch. Line relay 308, upon deenergizing, at armature completes a circuit for energizing relay 307 as follows: from ground by way of armature 327 and its resting contact, armature 329, armature 331 and working contact, armature 334, and winding of relay 307 to battery. Relay 307, upon energizing, at armature 323 maintains relay 309 in its energized position; at armature 324 connects pick-up relay 314 to the common pick-up lead 134 by way of conductor 134; at armature 326 grounds the interrupter start lead 132 by way of conductor 132', and at armatures 322 and 325 disconnects the line relay 308. from conductors 304 and 306, respectively, and connects said conductors instead to ground at armature 338 and battery through the upper winding of ring-cut-oil relay 311.

Resaonsiveto the roundin of the interrupter start lead 132 relay 207 energizes and initiates the operation of the code interrupter. The code interrupter now operates in the same manner as previously described.

In position 1 relay 200 energizes and connects ground to conductors 133 and 134. in position 2 relay 201 is energized and in position 3 relay 202 is energized in the manner previously described. 7

W hen ground is connected to conductor 134 relay 314 energizes and prepares at armature 339 the ringing circuitv of ringing relay 313. At armature 340 relay 314 closes an energizing circuit for relay 315 whereupon said relay energizes; and at armature 341, relay 314 completes a locking circuit for itself by way of armature 336 and 330. Belay 315, upon energizing, at armature 342 connects ringing relay 313 to wiper 347 of switch S Since the first code digit was 2 the wiper 347 is in engagement with the second bank contact which is connected to the common conductor 136 which in turn is connected to the number 2 cam and brush set. Accordingly, two long ringing impulses in positions 6-7 and 9-10 are sent to the ringing relay 313. Ringing relay 313, upon energizing, at armature 338 connects generator to conductor 304 from whence it extends by way of bank contact 300, wiper 95, working contact of armature 49 and said armature, conductor 33, wiper 27, armature 19, conductor 11 through all of the subscribers ringers to conductor 12, armature 17, wiper 25, conductor 31, armature 53 and its working contact, wiper 95, bank contact 303, conductor 306, armature 325 and its working contact, and through the upper winding of ring-cut-off relay 311 to battery.

when the code interrupter reaches position 12 ground is removed from the control lead 233 and relay 203 energizes and opens the circuit of relays 200 and 201. Relay 200, upon releasing, removes ground from conductor 133 whereupon relay 315 deenergizes and at armature 342 transfers the circuit of the ringing relay 313 from wiper 347 to wiper 349 which it will be remembered is in engagement with the third bank contract. Since conductor 137 is connected to the number 3 brush and cam set three ground impulses will be transmitted in positions 14, 16 and 18 for energizing ringing relay 313. Relay 313 again connects generator to the calling line in accordance with the code impulses. The code interrupter continues to operate in the same manner as previously described until the called party answers or until the calling party again removes his receiver. The operation is the same regardless of whether the calling or the called party is the first to remove his receiver. When the called party answers during a silent period, a circuit may be traced from ground by way of armature 338 and its resting contact over the subscribers loop to battery through the upper winding of ring-cut-off relay 311 whereupon said relay energizes. Relay 311, upon energizing, at armature 333 removes ground from the release-trunk conductor 305 thereby permitting the switchingthrough relay 34 of the connector and line switch C to release; at armature 334 opens the circuit of relay 312; at armature 335 completes a temporary locking circuit for itself; and at armature 336 relay 3,11 opens the locking circuit of relay 314 whereupon the latter relay deenergizes. At armature 336 relay 311 also opens the locking circuit of relay 316 but said relay does not deenergize until the off-normal springs 348 open when the wipers 346 and 347 reach their normal position; Relay 307, upon deenergizing, at armature 323 opens the circuit of the release relay 309; at armature 324 opens the initial energizing circuit of relay 314; at armature 326 removes ground from the interrupter start lead 132; and at armatures 322 and 325 disconnects the ring-cut-oif relay 311 from trunk conductors 304 and 306 and again substitutes the line relay 308. A short interval thereafter release relay 309 deenergizes and completes the circuit for operating the release magnets 320 and 318 as follows: ground by way of armature 330 and its resting contact, armature 322, and winding of release magnet 320 of switch S to battery; and ground by way of armature 330 and its resting contact, armature 345, winding of release magnet 318 to battery. By the operation of the release magnets 318 and 320 switch wipers 346, 347 and 349 are returned to normal position. When said wipers reach normal position off-normal springs 348 and 350 open, thereby opening the circuits of relays 316 and 310 whereupon said relays deenergize. At armatures 345 and 332, respectively, relays 316 and 310 open the circuits to the release magnets 318 and 320. The reverting call switch RC8 is now in normal position and may be used for other calls.

When ground was removed from the release-trunk conductor 305, switchingthrough relay 34 of the connector releases and at armature 52 closes a circuit for energizing the release magnet 47 of the connector H as follows: grounded armature 52, armature 59 and its resting contact armature 62 and its resting contact, off-normal springs 58, winding of release magnet 47 to battery. By the operation of release magnet 47 the connector H is returned to its normal position at which time the off-normal springs 58 are opened thereby opening the circuit of release magnet 47. The connector H is now in normal position and may be used for extending other calls.

When ground was removed from releasetrunk conductor 305, switching relay 14 of line switch C also releases and line switch C returns to normal position. However, since the called party closes the bridge across the talking conductors 11 and 12,, line switch C operates in the same manner as previously described to seize another connector. It will be assumed, in this case, that the line switch G again seizes the connector H and therefore line and release relays 36 and 37 of the connector H again energize. The line relay 36 is used for furnishing ing of ring;

battery to the calling and called subscribers.

Since the bell of the calling subscriber rings at the same time that the bell of the called subscriber does, the calling subscriber will know when the called man has answered by the non-operation of his bell for a certain period of time. The'calling subscriber will now take ofi' his receiver and talk with the called subscriber.

When both subscribers hang up, the line and release relays 36 and 37 will release and remove ground from release-trunk conductor 32 thereby permitting the releasc of the line switch C. All the apparatus is now in normal position and may be used for extending other calls.

Having described the manner in which two ring codes are transmitted, a brief eX- planation will now be given of the manner 1 in which one ring codes are transmitted.

F r this purpose we will assume that the connector is again seized and that the calling party, after operating the connector to the line of the desired party and said line is idle, dials the code digit 9. in the same manner as previously described the code switch S moves its wipers 115 and 116 to their IGSUSCtlVG 9th bank contacts. Now as soon asthe series slow acting relay 33 in 3 the connector H'deenergizes after the code impulses, a circuit may be traced for energizing relays 111 and 112 as follows ground by Way of armature and its resting contact, conductor 101, oil-normal springs 11'? "5 to the lower Winding of relay 112 and to battery, and over another branch by way of conductor 131, the multiple connected banlr contacts, wiper 115, and winding of relay 111 to battery. By the operation of relays 111 and 112 the interrupter start lead 132 is grounded whereupon the code interrupter is started in the same manner as previously described. In position 1 relay'200 is again energized and again connects ground to the pick-up conductor and the reverse conductor 133. The pick-up and reverse relays 110 and 100 are again energized to close the ringing circuit from wiper 115 to ringing conductor 102. In position 2 relay 201 of the code interrupter energizes and loclrs. In position 3 relay 202 energizes and closes the ringing circuit at armature 218 to the number 5 cam and brush set. In positions 1', 6, 8, and 10 the circuit to the ringing relay -10 oi the connector is closed over the following path: from ground by way of the multiple connected armature-s 230, number Scam and brush set, armature 231, armature 218, common'conductor 133, the number 9 bank contact of switch S withwhich Wiper 115 is now in engagement, worlri contact of armature 118 and said armature, armature 110, ringing lead 102, and windn relay 10 to battery. F our impulses of ringing current are now sent out by the ringing relay 10 to signal the desired subscriber. In positions 5, 7, 9 and 11 ground is removed from the ringing lead 102 and the ringing relay therefore interrupts the ringing current. In position 12 relay 203 again energizes and again causes the denergization of relays 200 and 201. The code interrupter now passes from position 12 to position 25, or normal position, in the same manner as previously described, but in this case without sending any ringing impulses because the switch S in the code sel ctor CS has not been operated. The code interrupter continues to send out the ringing impulses until the called party answers at which time the release of the code selector and code interrupter is the same as previously described.

It will be seen from the foregoing that although the calling subscriber dialed the number 9 code digit only a one ring code of four rings was transmitted. In a lilre man ner it is obvious from the wiring of the code selector bank contacts of the switch S that one ring codes comprising one ring, two rings, three rings, and five rings may also be transmitted when the code digits dialed are 6, 7, 8 and 10, respectively. It is also obvious that as high as thirty different codes may be transferred, five of which consists of one ring codes from either the code solector or the reverting call switches in combination with the common code interrupter. From the foregoing is seen that the numher four code is taken oil 01"- the number 5 cam and brush set. This is because the number 1 cam and brush set is used for control ling relay operations in 'code selectors and the code interrupter. lVhcn the number four code is to be rung the first ring impulse of the number 5 cam is ineffective when the number 4 code is the first ring code of a two ring code because relay 202 of the code in terrupter does not close the ringing circuit till after the first ringing position of cam number is passed. In somewhat similar manner the last ring of the number 5 code is ineffective when the number 1 code is the last code ring of a two ring code because relay 202 of the code interrupter falls back in position 21 thereby rendering the last ring impulse from cam number inell'ective.

It is also obvious that since the code interrupter ofFig. 3 isa common interrupter it may be used simultaneously by any number of code selectors or reverting call switches. Since relays such as 110 in the code selectors and relays such as 314 in the reverting call switches can only be energized in positions 1 and 2 of the code interrupter there is no danger of the common code int rrupterinitiating the ringing of a new code in any position other than in position 1 and 2 or" the code interrupter.

A brief explanation will now be given of subscriber will replace the manner in which a rural line subscriber such as sub-station A controls the connectors such as H and code selector such as WVhen the calling subscriber A removes his receiver a circuit may be traced from ground by way of the impulse springs of the calling device CD through the ringer coils in parallel over conductors 218 and 219 and thence by way of the two right hand windings oi the repeating coil through the winding of relay 218 to battery. Relay 213 energizes over the above traced circuit and at armature 215 closes a loop for energizing the line relay 207 of the line switch C. Line switch C now energizes in the same manner as described for the line switch C in Fig. 1 and seizes an idle connector, such as the connector H. When the calling subscriber A dials the digits of the called number the interrupter springs of the calling device CD interrupt the circuit of relay 213 whereupon relay 213 at armature 215 interrupts the loop circuit extending to the seized connector. The connector H and the code selector OS are operated in the same manner as previously described. At'ter the conversation the calling his receiver thereby interrupting the circuit of relay 213. Relay 213, upon deenergizing, at armature 215 opens the loop circuit thereby permitting the switches to release in the same manner as previously described.

Having described the invention, its utility and operation, what is considered new and is desired to have protected by Letters Patent will be set forth in the appended claims.

WVhat is claimed is:

1. In a code signalling machine, a plu rality of cam and brush sets each arranged to trasmit a different predetermined number of code impulses, another cam and brush set controlling the starting and stopping of the transmission of the code impulses, means -lor selecting one of said brush sets over either of two paths, and a relay controlled by said starting and stopping brush set for cancelling one of the code impulses adapted to be transmitted by the selected brush set in case said set has been selected over a particular one of said paths.

2. In a party line telephone system, a plurality of automatic connectors for completing connections to called lines, a code selector individual toeach of said connectors for selecting code signals corresponding to desired stations on connected called lines, a code interrupter comprising a plurality of cam and brush sets, means in said code selector for starting the operation of said interrupter, and multiple, connections connecting all the corresponding'bank contacts of all the code selectors and corresponding brushes on the interrupter.

3. In a party line telephone system, a plurality of automatic connectors for completing connections to called lines, a code selector comprising a pair of directively controlled switches associated with each of said connectors for selecting code signals corresponding to desire stations on connected called lines, a plurality of ring back mechanisms accessible to said connectors, each ring back mechanism comprising a pair of directively controlled switches for selecting code signals corresponding to desired stations on the calling line, a code interrupter comprising a plurality of cam and brush sets, and multiple connections connecting all the corresponding bank contacts of all said switches and corresponding brushes on said interrupter.

4. In a code signalling machine, a plurality of cam and brush sets each arranged to transmit a different predetermined number of code impulses, one of said sets selectable over two paths, and means operative in case said one set is selected over one of said paths for cancelling one of the code impulses of the predetermined number.

5. In a telephone system, a line, a plurality of connector switches, a pair of auxiliary switches individual to each of said connector switches, means for establishing a connection with said line by means of any of said connector switches, a code ringing interrupter common to said switches, means for successively and directively operating the pair of auxiliary switches associated with the connector in use to select a particular code ring, a circuit for controlling the opera tion of said common interrupter, means responsive to the completion of the directive control of said auxiliary switches for closing said circuit to initiate the operation oi said interrupter, and local circuits in said interrupter independent of said first circuit for returning said interrupter to normal position.

6. In a telephone system, a line, a plurality of connector switches, a code selector individual to each connector, means for controlling any one of said connectors to establish a connection with said. line and for operating the associated code selector to select a particular code ring, a code ringing interrupter common to said switches for transmitting all the code ringing impulses, and means in said associated code selector for initiating the operation of said interrupter to send code ringing impulses corresponding to the position of the operated code selector.

7. In a telephone system, a code ringing machine comprising a plurality of cams having notchesindentations therein, a brush for cooperation with, each of said cams for closing circuits when said brushes encounter the indentations on said cams, two directively controlled switches successively operated to select two of said brushes, means responsive assigned to the sub-stations of to a call for initiating the operation of said machine, a ringing relay when energized for transmitting ringing current, means for energizing said relay a plurality of times,

the number of times dependent upon the brush selected by the first operated switch, means controlled by one of said cam and brush sets for transferring the control or said relay to the brush selected by the last operated switch and means for then operating said. relay a plurality of times under control of said last selected brush and its associated cam.

8. The combination, with a ringing relay, of a code ringing machine comprising a plurality of cam and brush sets for transmitting a pluarlity of series of code impulses to said relay, a plurality of progressively movable switches for registering the code ringing digits in a called number, and relays cooperating with one of said cam and brush sets in said machine for placing the transmission of the series of code impulses under control of said register switches suc cessively.

9. In a telephone system, two classes of sub-stations, three digit teleohone numbers one class, four digit telephone numbers assigned to the substations in the other class, automatic connector and code selector responsive to the calling of a 3 digit number to call a subscriber in the first class and responsive to the calling of a four digit number to call a subscriber in the second class, and a common ringing equipment automatically started in each case when the calling of the number is completed to selectively signal the wanted sub-station by one ring and two ring codes, respectively.

10. In an automatic telephone system wherein party line subscribers are selectively signalled by code rings, a plurality of connectors having individual code selectors for directively selecting a one ring code or a two ring code dependent upon the number dialled, and a code interrupter common to all said connectors and code selectors for controlling the application of ringing current in accordance with the setting of the code selectors.

11. In an automatic telephone system wherein party line subscribers are selec ively signalled by either one or two ring codes, a connector and means for operating said connector into engagement with a called subscribers line, a first ringing switch associated with said connector for controlling the series of ringing impulses in a one ring code and the first series of ringing impulses in a two ring code, means setting said first switch in'accordance with the code digit in a one ring code in case a one ring code digitis dialled or for setting said switch in accordance with the first cede digit. of a two ring code and the second switch in accordance with the second code digit of a two ring code, a code interrupter common to said connector and switches and other similar connectors and switches, and means controlled by the completion of the setting of both said switches in case two code digits are dialled or by the completion of the setting of said first switch in case a one ring code digit is dialled for initiating the operation oi said common interrupter.

12. In a telephone system, a party line connector having primary and secondary magets, two auxiliary ringing current selecting switches individual to said connector, each ringing switch having a motor magnet, a line relay and a series relay in said connector, impulsing circuit to each ofsaid mnets controlled by said line relay, said series relay included in said impulsing circuits, contacts on said series relay for causin said magnets to be successively con trolled by said line relay, and means including oil-normal springs on the first of said ringing switches in series with said contacts for causing the impulsing circuit to be trans ferred from the magnet of the first ringing switch to the magnet of the second ringing switch.

in an automatic telephone system wherein party line subscribers are selectively signalled by two series of code rings, a revel ng call switch comprising two ringing switches for enabling calling subscribers to call other subscribers on their own line, means for seizing said reverting call switch and for operating both said ringing switches select a two ring code, and a code interrupter common to said switches and similar switches for controlling the transmission of the two series of ringing impulses in accord ance with the setting of the ringing switches. 14. in an automatic telephone system wherein party line subscribers are selectively signalled by two series of code rings, a reverting call switch comprising two ringing switches for enabling calling subscribers to call other subscribers on their own line, means for seizing said reverting call switch and for operating both said ringing switches to select a two ring code, a code interrupter common to said switches and similar switches for controlling the transmission of the two series of ringing impulses in accordance with the setting of the ringing switches, a ringing circuit over which said ringing impulses are transmitted, and means con trolled by said interrupter for transferring the ringing circuit from the first ringing witch to the second ringing switch after the transmission of the first series of ringing impulses. I V

* 15. in an automatic telephone system wherein party line subscribers are selectively by two series of code rings, a re verting call switch comprising two ringing switches for enabling calling subscribers to call other subscribers on their own line, means for seizing said reverting call switch and for operating both said ringing switches to select a two ring code, a code interrupter common to said switches and similar switches for controlling the transmission oi": the two series of ringing impulses in accordance with the setting of the ringing switches, a ringing circuit over which said ringing impulses are transmitted, and means controlled by said interrupter for transferring said ringing circuit from the first ringing switch to the second ringing switch after the transmission of the first series of ringing impulses and for transferring the ringing circuit from the second ringing switch back to the first ringing switch after the transmission of the second series 0]": ringing impulses in order to repeat the first series of ringing impulses.

16. In a telephone system wherein party line subscribers are selectively signalled by two series of code rings, two ringing switches, means for operating said switches to select a two ring code, a ringing relay for connecting ringing current to the called party line, a circuit over which code impulses are sent for operating said relay, and means for transferring said circuit from the first switch to the second switch after the transmission of the first series of code rings in order to control said relay to transmit the second series of code rings.

17. In a telephone system wherein party line subscribers are selectively signalled by two series of code rings, a reverting call switch comprising two ringing switches for enabling calling subscribers to call back on their own line, means for seizing said reverting call switch, means for operating said ringing switches to select a two ring code, and means for transmitting two series of ringing impulses in accordance with the setting of said ringing switches.

18. In an automatic telephone system wherein party line subscribers are selectively signalled by either one or two ring codes, a reverting call switch comprising two ringing switches, means for seizing said reverting call switch and for operating both said ringing switches to select a two ring code in case a two ring code is called or for operating only the first of said ringing switches to select a one ring code in case a one ring code is called, and a code interrupter common to said switches and similar switches for controlling the transmission of the series of ringing impulses in accordance with the setting of the ringing switches.

19. In an automatic telephone system wherein party line subscribers are selectively signalled by either one or two ring codes, a reverting call switch comprising two ringing switches, means for seizing said reverting call switch and for operating bothsaid ringing switches to select a two ring code in case a two ring code is called or for operating only the first of said ringing switches to select a one ring code in casea one ring code is called, a code interrupter'common to said switches and similar switch for con trolling the transmission of the series of ringing impulses in accordance with the setting ot the ringing initiating the operation of said interrupter responsive to the setting of both ringing switches in case a two ring code is called and responsive to the setting of the first ringing switch only in case is called.

20. In combination, an interrupter mechanism comprising a plurality of cam and brush sets, a switch equipped with two sets of wipers adapted to be positioned for selecting said sets, and a starting circuit for said mechanism controlled by a single wiper in certain position and by the two wipers jointly in said other positions.

21. In combination, anism comprising a plurality of cam and brush sets, a switch equipped with two sets of wipers adapted to be positioned for selecting various pairs of said sets, a signal circuit for said switch, and a relay controlled by said mechanism for connecting said two wipers alternately to said signal circuits.

22. In a telephone system, a party line connector having primary and secondary motor magnets, two auxiliary ringing current selecting switches individual to said connector, a motor magnet for each ringing switch, a line relay in the connector for controlling the primary and secondary magnets thereof to extend a connection to a line, and a switching relay in the connector for placing the motor magnets of said ringing switches under the control of said line relay when a connection is extended to an 1 idle line.

23. In a telephone system, a party line connector, a line relay in the connector for controlling the operation thereof to extend a connection to a called line, a switching relay in the connector energized when a connection is established with an idle line, a first code selecting switch placed under the control of said line relay responsive to the operation of said switching relay, and a second code selecting switch placed under the control of said line relay responsive to the operation of said first switch.

24:- In a telephone system, a party line connector, a line relay in the connector for controlling the operation thereof to extend a connection to a called line, means for testing the line connected with for its busy or idle condition, two code selecting switches switches, and means for a one ring code an interrupter mechare individual to said connectors, and means responsive when the line connected with is idle for successively placing said switches under the control of said line relay.

In Witness whereof, I hereunto subscribe my name this 28th day of June, A. D. 1928.

NORMAN H. SAUNDERS.

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