US1778309A - Telephone metering system - Google Patents

Description

Oct. 14, 1930;

' w. WICARPENTER ET Al- TELEPHONE METERING SYSTEM Filed May 31, 1929 /N VE N TORS 4 Sheets-Sheet l l I I I I l I W CARPENTER L. H. Jamvs0- Oct. 14, 1.930. w, w, CARPENTER Er AL 1,778,309

' TELEPHONE METERING SYSTEM Filed May 53m 1929 4 Sheets-Sheet 2 w m h N f m \mw mN SQEW W 1 M www N A TTOHNE) 0a. 14, 1930. v w. w. CARPENTER ET AL 1,778,309

TELEPHONE METERING SYSTEM Filed May 31, 1929 4 Sheets-Sheet '3 W CARPENTER WVENTOR" L. H. Jam/501v '4 7' TORNE) Oct. 14, 1930. E w, w, CARPENTER ET AL 1,778,309

TELEPHONE METERING SYSTEM Filed May 31, 1929 4 Sheets-Sheet 4 W W CARPENTER WVENTOHS. L. hi JOHNSON ATTORNEK Patented Oct. 14, 1930 um rel) STATES PATENT *oFrrcE WARREN w. CARPENTER, or ennnns viLtA en, NEW YORK, AND LEWIS) ioHNs'oN,

on MAnrso NEW JERSEY, AssrG ons TO BELL TELEPHONE LABORATORIES, 1N- oonroan'rn'n, or NEVI Yon-K, N. Y., A CORPORATION on NEW YORK TELEPHONE METERING SYSTEM Application filed May 31,

This invention relates to dial telephone systems, and more particularly to metering calls on multi-party telephone lines. The object of the'invention is increased economy and ethciency in the apparatus necessary for this purpose. 7

The embodiment of the invention chosen for the purpose of illustration comprises a meter control c rcuit common to the hnes apby Way of the district selector and line finder .to the metering terminal. After a measured interval the meter control equipment is dis connectedjirom the selector. The control equipment is so arranged that in the case of an individual line Where the meter is connected directly to the metering terminal, in which case no registration is set up in the district selector, application of metering current is rendered independent of the connectirg relays. Likewise means is provided to discriminate between the condition where the lack of registration is due to the calling line being an individual line and that due to a fault in the setting up of the registration. In the latter case the circuit is arranged to indicate on meter that no registration was made and scans is also provided in the selector whereby this no registration condition can be to operate an alarm,

The invention will be more clearly understood trom a consideration of the following description in connection with the attached drawings in which 1 shows a portion of a district selector, .Fig, 2 shows a four-party line, an individual line,1and the common meter control equip1nent,,Fig. 3 shows one complete party identification circuit, Fig. 4 shows 1929. Serial No. 367,259.

portions of two other identification circuits, and Fig. 5 is a diagram indicating the manner in which the other figures should be arranged,

Briefly, when a call is initiated thecalling line is associated with a district selector by any suitable means, for example, a line finder. The district selector is then associated with an idle sender and the wanted line number is recorded in the sender which thereupon controls the selective operations of the district selector and other switches. .lVh'en selections have been completed a relay is operated which connects an idle identification circuit with the calling line. The operation of this relay connects a network in ilel with a section of the talking circuit as 1:; extends through, the district selector and then opens the talking circuit to insert the network therein. The identification circuit then connects a relay to both sides of the line in parallel to determine whether the substation calling is grounded andthen in effect applies battery first to one side of the line and then to the other to operate the polarized relay at the substation which, by its response, determines the registration. Following the registration the line is reclosed and the identification circuit isdisconnected from the selector. When the called subscrib er answers and the charge relay operates as an indication that the call has been successful, a meter control circuit is associated with the dist selector under the control of the registra ion set up by the identiiicruzion circuit. The meters of the corresponding party of all lines located on the same frame are connected to the respective metering terminals of the line. For example, it the calling substation were substa on #1, thenthe #1 meter for every party line appoaringin the same panel would be connected to the metering terminal. of the corresponding line. This operation initiates the application of metering current to the metering terminal for a measured interval after which the e rrent is removed and the meter control circuit disconnected from the district selector.

i that the subscriber at substaceiver from the switchhook at the substation actuates the line relay 100, thus initiating the operation of a trip, start and link circuit. These circuits in turn bring about the operation of a partlcular line tinder LI1Cl'dlS- trict selector for the purpose of extending the call. The line finder, for example line fmder 101, connects with the calling. line,

after which theline is associated with a sender. The operation of thedial' on the calling line registers the number of the wanted subscriber in the sender in accordance with which the sender controls the operation of the district selector 102 and other switch-- show or describe the apparatus and its func- 1710115111 detail. Reference'is hereby made to U. S. Patent 1,589,402, granted January 22,

1926 to O. H. Kopp, for a detailed descrip tion of the establishment of a connection through equipment'of the type shown.

'As set forth in the above identified patent, the operations of the line finder 101 and dis trict selector 102 take place in positions 1 to 9 inclusive of the sequence switch while those of the switching apparatus to which the district selector has access, take place with the district selector sequence switch in position 10. When the selections have been completed, indication ofthis is returned to the sender which advances the district selector sequence switch from positionlOto position 12. As soon as the sequence switch leaves position 10, a circuit is closed from-battery, through the windingof relay 103, lower contacts of sequence switch cam 10%, lower back contact ofrelay105, upper back contact of relay 112, to ground at'the back contact of relay 300. This circuit also extends to ground at the back contact of relays 400 and 450 so that should relay 300 be operatedbecause of a failure of the identification circuit, as will be described hereinafter, relay 103 will-nevertheless be operated. Relay 103' looks over its lower front contact and the back contact 7 of relay112 to ground at the back contact of relay 300, thus rendering itselfindependent of the sequence switch and 1 of relay 105. 'Relay103 in operating closes a circuit from battery, through its upper front contact,'lower winding of relay 106, lower back contact of relay 301, lower back contact of relay 302, winding of relay 303,

lower back contact of relay 304, to ground. Relay 106 operates, locking through its upper winding and over its upper front contact,

, innerback contact of relay 305, winding of relay 304, upper back contact of relay 302 to ground. The closure of the upper contact of "nect network 310 in parallel with 'aportion of the talking circuit, namely, thatpart passing through the contacts of relay 105. These circuits may be traced :from the tip brush of the line finder, fourth contact of relay 107, upper back contact of relay 306to the upper right terminal of thenetwork, through the upper retardation coil, uppermostback contact of relay 311, upper back contact of relay 307, sixth contact of relay 107, to the tip conductor of the talking circuit at a point beyond the-contact of relay 105 from the ring brush of the line-finder, third contact of relay 107 inner back contact of relay 306, to the lower right terminal of thefnetwork'310, lower retardation coil, middle back contact of relay 311, through the winding of relay 312, inner back contact of relay 307, fifth contact of relay 107 to the ring conductor at the right of the contact of relay 105. By the same operation the lower'winding of relay 315 is bridged across the repeating coil of the district selector completing a circuit from battery through the lower left winding of repeating coil 108, inner upper back contact of relay 109, fifth contact of relay 107, inner back contact of relay 307, upper normal contact of relay 316, lower winding ofrelay 315, upper back contact of-relay 307, sixth contact of relay 107, upper "back contactof relay 109, upper left winding of repeating coil 108 to ground. -Relay 315 operates in this circuit and initiates the testing .of the calling line. The operation of relay 315 com pletes a circuit from ground at its upper T front contact, inner backcontact ofrelay 309,

middle lower front'contact of relay 106, up per windingofrelay tobattery. Relay 105 operates, opening the talking circuit at itscontacts and thus introducing thenetwork 310'into the talking circuit so that the subsequent test may produce no unpleasant clicks or other noises to disturb the conversation.

i/Vith the inclusion of the networkin the talk ngclrcuit relay 312 is IIIClLlClQCllII a circuit fed by battery through the repeating coil 108 and extending over the subscribers line. in which circuit relay 312 operates provided the conductors connecting the identificationv circuit and the district selector as well as the subscribers line are uninterrupted.

Thec'losure of the locking circuit of relay 106 causes the operation of relay 304L- which V in turnoperates, relay 301 to prevent the 240 has a polarized relay and a grounded transfer of the call to another identification circuit. Relay 304 also closes a circuit over its lower front contact, lower back contact of relay 313, winding of relay 314 to battery, preparing a timing circuit for determining whether the tests are completed properly. It also connects ground over conductor 320 to the armature of relay 312.

Assuming that relay 312 operates, a circuit is closed from battery, through the winding of relay 313, lowermost back contact of relay 311, contact of interrupter 317, front contact of relay 312 to grounded conductor 320. Relay 313 looks through the winding of relay 311, over the upper front contact ofrela 313-to grounded conductor 320. Belay 311 does not operate until interrupter 317 opens its contact to open the shunt around the winding of relay 311. WVhen relay 311 operates the subscribers line is disconnected from therepeating coil but relay 315 remains bridged across the repeating coil holding the connection. The two sides of the subscribers line are then extended over the upper front contacts of relay 311 and the back contacts of relay 318 to the winding of relay 319 and battery, to determine whether the calling party is one identified by ground.

Examining Fig. 2 for a moment it will be apparent that each party 210, 220, 230, and

contact associated with the substation. With the receiver removed from the switchhook the substations 210 and 220 are not grounded while substations 230 and 240 have ground connected through the winding of the polarized relay to the line. In the case of substation 230 the ground extends over an auxiliary contact of the switchhook, back coni tact of polarized relay 231, retardation coil 232 v upper winding of polarized relay 231, through the switchhook, transmitter and dial contact 236 to'the ring conductor, and

through both windings of the polarized rej lay and one winding of the substation repeating coil to the tip conductor. In the case of substation 240 the ground extends over the auxiliary contact of the switchhook, back contact of relay 241, retardation coil 242, up-

.per winding of relay 241, left winding of coil 24-1'to the tip conductor while it extends through both windings of the polarized re-. lay through the switchhook, transmitter and dial contacts to the ring conductor. Since l .the subscriber at substation 220 was assumed to be calling ground will not be connected to eithertip or conductor and relay 319 will not be operated, It should be noted that the battery connected to relay 319 is the re- .verse'of that used elsewhere so that it has no effect onthe polarized relays at the substations.

V, conductor 320, middle front contact of reoperates and looks through the winding of relay 0 and the lower front contact of relay 318 to grounded conductor 320 but relay 322 does not operate until interrupter 317 opens its contact. VJhen ground was connected to conductor 320 a circuit was also closed over the lower back contact of relay 318 to the vinding of relay 326 and battery. Therefore, the operation of relay 318 extends the tip conductor of the subscribers line over the front contact of relay 311 front contact of relay 318, back contact of relay 322, to the upper winding'of relay 323 and battery and in parallel through resistance 341 and the inner upper front contact of relay 326 to battery. It also extends the ring conductor over the middle front contact of relay 311, inner upper front contact of relay 318, inner upper back contact of rel y 322, through the lower winding'of relay 323, to battery 325, through lamp 324 and in parallel with the winding of relay 323, through resistance 342 and the upper front contact of relay 326. Battery 325 is the usual coin battery and has a value of approximately 110 volts while the battery connected to the upper winding of relay 323 1'7 is approximately volts. T he net result of the use of these two batteries is the same as though one 50 to volt battery were connected to the side of the line to which the coin battery is connected. The purpose served by using the two batteries will be apparent hereinafter. The operation of relay 318 opens the circuit of relay 326 which is slow to release and, therefore, after a short interval opens the shunts closed through its contacts around the windings of relay 323. This, therefore, permits the polarized relay in the substation to operate, if it is going to, before relay 323 becomes effective. In the present case polarized relay 221 operates since it is so connected and polarized as to respond to negative battery applied to the ring conductor. Vhen relay 221 operates it connects ground over the auxiliary switchhook contact, front contact of relay 221, through retard coil 222, upper winding of relay 221, contact 226, transmitter 225, dial contact 224 to the ring conductor. It also connects ground over the switchhook contact, front contact of relay 221, retardation coil 222, both windings of polarized relay 221, winding of repeating coil. 227 to the tip conductor. Therefore, when relay 326 releases opening the shunts around the windings of relay 323, this ground imbalances the circuit of differential relay 323 so that the relay operates and closes a circuit from ground, over its front contact, inner back contact of relay 308, innermost lower front contact of relay 106, winding of relay 109 to battery. Relay 109 loo f operates and locks over sequence switch cam of relay 311,318, and 322, the upper winding 110 to ground. 7 It is to be noted thatthe windings ofrelay 323 are so proportioned that the current flowing through them from 110 volt battery 325, over a loop at the subscribers substation, to central olhce battery connected to the upper winding of relay 323 maintains therelay unoperated whereas with ground connected to the circuit at the substatiom-the current through one winding is reversed and results in the operation of the relay. The same holds'true ofrelay 327.

8 At the time that relay 326 was operated a circuit was closed from battery, through the winding of relay 328, inner lower back contact of relay 322 to grounded conductor 320. Therefore, when relay 322 operates following the opening of the contact of interrupter 317, the tip conductor of the calling line is GX- tended over the outer upper front contacts of relay 327, and in parallel therewith through resistance 343 and the upper front contact of relay 328, through lamp 324 to 110 volt battery 325. The ring conductor is extended over the inner upper contacts of relays 311,318 and'322 to central office battery through the lower winding of relay 327 and in parallel therewith throughresistance 344 and the inner front contact of relay 327 to central ohice battery. As in the case ofrelay 323 relay 327 cannot operate with its winding shunted in this manner. The operation of relay 322 opens the circuit of relay328 and. when this relay releases after an interval the windings of relay 327 are connected directly to the line. Since the polarized relay 221 responds only to battery over the ring conductor it does not'operate at this time and, therefore, does not connect ground to the line,

leaving relay 327 unoperated.

The next closure of the contact of interrupter 317 completes a circuit fromconductor 320, front contact of relay 313, contact of interrupter 317,. innermost front contact of relay 311,.back contact of relay 321, lower-' n ost'front contact of relay 322, winding of relay 316 to battery. Rela 316 operates and locks to conductor 320.. It also connects ground from conductor 320, over its inner-' mos-t lower contact to the winding of'relay 313, holidi'ng that relay operated but shuntmg relay 311 which releases restoring the connection between the repeatingcoil 108 and the calling'line. Relay 312 reoperates. Relay 316 also closes acircuit from battery, through the winding of relay 314, lower front contact, of relay-315, lowermost front contact of re lay 316 tocrounded conductor 320. The op-.

eration of relay 312 opens the locking circuit ofrelay 315 and the operation of relay 316 connects resistance 329 in parallel with the 7 7 operating'winding of relay 315, thus releasing relay315. The release of relay 315'opens V, the circuit of relay, 105 and that relay releases restoring the talking circuit to itsnormal condition. I The release of relay 315 also opens the circuit of relay 314. The reclosure of the talking circuit shunts the winding of relay 312 which now releases. A circuit is now closed from battery, through resistance 111, winding of relay 112, lowermost front contact of relay 106, upper back contact of relay 309, upper back contact of relay 315, innermost front contact of relay 313, back contact of relay 312 to grounded conductor 320. Relay 112 locksover-its inner upper front contactto ground over cam-110. The operation of relay 112 opens the locking circuit of relay 103 and'that relay releases in turn releasing relays 106 and 107, followed by the release cfrelay 304. The release of relay 304 disconnects ground-from conductor 320, thus releasing relays 313, 316, 318, 322 and 301. v

VVhenth-e called subscriber answers polarized relay 113 operates in the well known manner. .A/CllCLlle is thereupon completed froin'ground, over cams 114 and 115, front contact ofrelry 113, earn 116, left contact of interrupter117, windingof relay 118 to battery. Relay 118 operates and looks over canis- 119 and 116,front contact of relay 113, came 115 and 114 toground. When interrupter 117 closes its right hand contact a circuit is closed from ground as previouslytraced, over the inner upper front contact of relay 118, cam 120, winding of relay 121 to battery. Relay 121 locks over its upper front a operated a circuit is closed from battery, over the lower front contact of relay 121,-inner lower front contact of relay 112, upper winding of relay 122, winding of relay 250, back contact of relay 251, back contact of relay 252 to ground, assuming that the meter control circuit is idle. Belay 250 operates .momentarilv, but relay 122lockst1rough its lower winding and front contact to the winding of relay 252 which onerates opening the energizing circuit for all relays-such as relay 122 and releasing relay250. Relay 252 also closes a circuit from ground, through its front contact, windin r of relay .251 to battery.

from ground at the front contact of relay 252, inner left frontcontact of relay 251, middle upper front contact of relay 122, al-j Relay 253 is one of four party relays each i of which is individual toone of the four parties connected to a party line. For exthe line finder Relay 251 operates andcloses a circuit ample, relay 253 is individual to the second party and relay 237 is individual to the third party. The line finder and district selector of Fig. 1 is arranged to serve a maximum of four hundred lines. As will appear hereinafter these lines may be either individual lines or party lines. If all of the lines served by this 2 finder are party lines, it is necessary that each party relay prepare circuits for four hundred meters. Consequently, each party relay is arran d to operate ten multi Contact relays each of which in turn controls forty contacts. here individual lines appear on the same line finder frame with party lines, the corresponding contacts of the multi contact relays need not be equipped. The operation of relay 253, therefore, by operating the multi-contact relavs 254, 255, etc., prepares circuits for all of the second party meters belonging to the party lines served by the district selector of Fig. 1.

The operation of relays 255 and 254 closes a circuit from ground, over their right front contacts, right back contact of relay 256, right back contact of relay 257, winding of relay 258 to battery. Relay 255 also prepares a circuit from ground through the winding of message register 223, outer left front contact of relay 255, back contact of line relay 100 (which is 110w deenergized having been released by the operation of cutoff relay 125 when the line was found in the well known manner), to the metering terminal 126 of the calling line. The circuit may be further traced over the line finder brush, uppermost front contact of relay 122, inner right front contact of relay 258, winding of relay 259 to battery. Relay 259 operates for a purpose which will be described hereinafter. The operation of relay 258 also closes a circuit from battery, through the winding of relay 260, middle front contact of relay 258, left contact of interrupter 261. .l Vhen interrupter 261 closes this circuit relay 260 operates, looking over its inner front contact to ground at the front contact of relay 252. lVhen interrupter 261 closes its right contact it completes a circuit from ground, over the uter front contact of relay 260, innermost upper front contact of relay 122, resistance 111 and battery. This shunts the winding of relay 112 and that relay releases opening the circuit of relay 122 in turn releasing relay 252, and restoring the meter control circuit to normal. Since the operating circuit of relay 112 was closed through the contact of relay l06,which is now released, it is impossible to make a second char e irrespective of the length of the conversation although it is obvious that there is nothing in the present inventive idea Hadthe subscriber at substation 230 been calling the removal of his receiver would have connected the ground over contact 238, back contact of relay 231, retardation coil 232, upper winding of relay 231, switchhook contact 234, transmitter 235, dial contact 236 to the ring conductor and through both windings of relay 231, left winding of the repeating coil to the tip conductor. zi lion therefore, relay 319 is connected to the tip and ring conductors as above described this relay operates. Relay 319 in operating closes a circuit from ground through the winding of relay 321, contact of relay 319, upper back contact of relay 305, innermost contact of relay 107, through the winding of relay 124 to battery. Battery through resistance 330 is connected in parallel with relay 124, thus insuring the operation of relay 321. WVhen relay 124 operates and locks over its inner upper front contact and the bot-tom contact of cam 110, this locking ground is connected in shunt of resistance 330 and battery, releasing relay 321. l/Vith relay 321 operated the interrupted ground controlled by interrupter 317 is transferred from the winding of relay 318 to the winding of relay 310 so that if relay 124 does not operate before the next closure of interrupter 317, the identification circuit will be dismissed and no registration will be set up in the district, resulting in a free call.

If the registration is made correctly the remaining tests are made as above described. Relay 231 is polarized to respond to battery connected to the ring conductor. Therefore, when relay 318 operates connecting battery 325 to the ring conductor, relay 231 operates disconnecting the ground at its back contact from the line. When relay 326 releases opening the shunt around the winding of relay 323 the current flow through that relay prevents its operation. WVhen battery 325 is connected to the tip of the line by the operation of relay 322, relay 231 does not operate and the ground remains connected. to the line. There fore, when the shunts are removed from relay 327, this ground causes the operation of relay 327 closing a circuit from ground, over the front contact of relay 327, upper back contact of relay 308, second front contact of relay 107. winding of relay 123 to battery. Relay 123 locks over its inner upper front contact to the lower contact of 110. When the registration equipment functions the meter selecting circuit may be traced from ground, over the outer right front contact of relay 258, inner left front contact of relay 251, middle upper front contact of relay 122, normal contact of relay 109, upper front contacts of relays 123, and 124, winding of relay 237 to battery. Relay 237 operates and connects the third party meter 233 to the metering terminal of the line ready to receive metering potential as previously ground to the line, relay 319 is operated in the manner described for substation230 in turn operating relay 124. Relay 241 does not respond to heavy battery connected to the ring conductor and, therefore, the ground which remains connected to the line operates relay 323 in turn operating relay 109. 'Relay 241 does-respond to battery connected to the tip conductor, and removes the normal ground thereby preventing the operation of relay 327.

To summarize:

If substation 210 calls, registration relay 123 operates. I

If substation 220 calls, registration relay 109 operates.

Ifsubstation 230 calls, registration relays 124 and 123 operate. .7

If substation 240 calls, registration relays '124 and 109 operate. Relay 109 serves the added purpose of reversing the direction of current flow through the substation so that the ground Will be re moved from the line during conversation. In-the case of substation 220 it prevents the operation of relay 221 While in the case of substation 240 it causes the operation of relay 241 to remove the ground.

The meter control equipment is especially arranged so that it'is possible to place party lines and individual lines on the same frames, so far as metering is concerned. An individual line Will not be provided With a polarized relay, grounded contact and a choke coil such as shownin connection with the'party line. Since there is no ground. at any point of the test none of relays 109, 123 or 124 is operated. The meter selecting circuit extends from ground over the front contact of relay 252, inner left front contact of relay 251, middle front contact of relay 122, normal contact of relay 109, upper back contact of relay 123, upper Winding of relay 127, windings of relay 256 to battery. Relay 256 operates and closes a circuit from battery, 7 through the Winding of relay 258, right back contact of relay 257 to ground at the outer right front contact of relay 256. It also closes a circuit from battery, through the inding of relay 259, inner front contact of relay 258, uppermost contact of relay 122, to the metering terminal of the individual line, over the back contact of the line relay (not shown) and the \v1nd1ng of message rc Relay 258 also'prepares a circuit from bat- Igister 202 to ground.

tery, through the Winding of relay 260,1niddle front contact of relay 258, to the left 'contact of interrupter 261-. When interrupter 261 closes that contact relay 260. operates and locks to ground at the outer front Contact of relay 258. Relay 260 prepares a circuit from ground, over the right contact of interrupter =261, outermost contact of relay 260, inner the identification equipment, the Winding of relay 127 is introduced in the circuit of relay 256 as above described. If the line is an individual line the message register Will be connected directly to the metering terminal and relay 259 Will operate in series therewith. If the lack of registration is due to faulty functioning relay 259 cannot operate. Therefore, When relay 260 operates battery is connected over the back contact of relay 259,middle front contact of relay 260, in shunt of the high resistance Winding of relay 256, thus reducing the resistance in series With relay 127. Relay 127 is marginal andcannot'operate as long as the high resistance Winding of 7 relay 256 is in its circuit. With this Winding shunted relay 127 operates and'closes a circuit over its lowermost contact, lowermost contact of relay 112, to the meter 128. A. record is, therefore, set up of the number of times that the eopuipmentv fails to register. This meter is common to the district selectors served by the identification equipment. If the number of failures recorded appears excessive, key 129 may be operated, locking relay 127 and flashing lamp 130 so that the identit y of the district selector may be determined. Belay 127 also opens the circuit of down drive magnet 131 of the line finder, preventing its restoration to normal and thus indicating the line With which the trouble arose.

Relays 262 and 263 serve to cause an alarm in case the meter control circuit does not operate properly. Battery is intermittently connected to conductor 264 and thewinding of relay 263 and after a measured interval is connected to conductor 265 and the Winding I of relay 262. The circuit of relay 263 extends to ground over the contact of relay 250 and the back contacts of relays 251' and 252 if relay 121 does not lock. It extends to ground over the front contact of relay 251 during the selecting and operation of the meters and also extends to ground over the front contact of relay 257 if the meter connecting relays such as relays 254 and 255 fail to operate following the operation of selecting relay 253 or if one of these relays operates falsely in the case of an individual line. 'VVhen battery is connected to conductor 264 While ground is connected to the other terminal of relay 263, relay 263 operates and looks through its inner front contact as long as the operating ground continues. If this ground remains long enough, the connection of battery to conductor 265 operates relay 202 in a circuit extending over the middle front contact of relay 263 to ground. Relay locks to battery over its inner left front contact and is helo operated under the control of relay lVith relay 262 operated a circuit is closed for one of the 23? or according to which no. operated relay 263 and an alarm is operated over conductor 269.

Relay 106 is indivi dual to the district selector and a siin -l relay such as relay 132, etc., is provided for each district selector of the group sermd by the identification circuit of Figs. 3 and 4:. lfhese relays are arranged in sequence and the locking circuit of any relay extends over the hack contacts of the relays following it in the sequence. Therefore, if two relays operate at the same time only the lower re-la in the sequence can loci; and the other district selector must await the release of the identification circuit. If, for any reason, this chain locking circuit is broken so that relay 106, for example, cannot lock, the operation of relay 303 in the energizing circuit of relay 106 prepares a circuit from ground, over the front contact of relay 303, right contact of interrupter 331, winding of relay 332 tobattery. Relay 332 looks over its upper front contact to the front contact of relay 303. Relay also closes a circuit from ground, over its front contact, lower contact of relay 313, wincin of relay 31a to battery. If relay 106 looks through the winding of relay 30d the circuit of relay 303 is opened at once and relay 332 cannot operate. With relays 332 and 314 both operated the closure of the left contact of interrupter 331 completes a circuit from ground at the front contact of relay 303, left contact of interrupter 331, lower front contact of relay 332, front contact of relay 314, winding of relay 333 to battery. Relay333 loclrs through its lower winding and lower front contact, key 33 1, winding of relay 335 to ground, thus oper ating. an alarm which can only be silenced by the operation of key 334;. It also lights lamp to indicate which identification circuit failed. Relay 333 also connects ground over its front contact, uppermost back contact of relay 309, lowermost contact of relay 106, which is operated but not locked, winding of relay 112, resistance. 111 to battery. Relay 112 releases relays .103, 106 and 303. Since no rep stration was set up the call will proceed as a free call. If relay. 103 locks, relay 30 1 operaltos in the locking circuit, opening the ci cuit of relay 303. HoweverQrelay 304 substitutes ground at its lower front contact for the ground at the front contact of relay 303. Therefore, the line is open so that relay 312 cannot operate, and in turn relay 313 does not operate, relay 31% remains operated. and the alarm operates as abovedescribed.

According to the present disclosure three identification circuits are provided to serve a large group of district selectors and each of these normally serves a particular part of the group. Means has been provided, howe ,so that if one identification circuit fails to function, one of the other identification cir its may be used. If the identification does take place wit-hm a predetcrn'nned time relay 332 is operated under the control of intenupter 331 and locks as above described. 1 1e operation of relay 313 releases relay 314 so that the subsequent closure of the left contact of interrupter 331 extends ground over the front contact of relay 332, back contact of relay 314:, to lamp 337, and winding of relay 300 and battery. Relay 300 extends its operating ground over the back contact of similar relays 100 and 450 of the other identification circuits, through the winding of relay 338, key 339, right winding of relay 3 10 to battery. Relays 338 and 34.0 operaJe, relay 3&0 sounding an alarm and locking to the alarm circuit. The operation of relay 338 connects ground over its front contact to the armature of relay 300, thus holding relay 300 operated when interrupter 331 opens its contact. Relay 300 also closes a circuit for relay 302. Relay 302 opens the circuit of relay i at its upper back contact and when relay 301 releases completes a. circuit over the upper front contact of relay 302, bacl: contact of relay 301, through the windof re ays 305, 306, 307, 308 and 309, in parallel to battery. Relays 305 to 309 in oping transfer the circuits which connect the d strict selector with this identification circ the identification circuit shown at the left of Fig. l. Since both identification circuits ind cated on Fig. 1 are identically the sar e as t shown in Fig. 3, only the transfer and switching relays have been shown.

If the second identification circuit should fail to complete its function in. the proper time the some operations will take place and the circuits further extended to the third identification circuit. In case all three fail, the operation of relay J0 of the third identification circuit opens the circuit of relay 338 and releases relays 300, 400 and 450. Calls may also be rerouted from the second lentification circuit to the third and first and from the third'identification circuit to the first and second in. the same way as they were advanced from the first t0 the third as above described.

If at the completion of the identification tests, relay 312 fails to reoperate, and consequeutly relay 315 does not release, a circuit is closed for relay 314, over the lower front contact of relay 315, outer lower front contact of relay 316 to grounded conductor 320, thus operating relay 333 and bringing in an alarm through the operation of relay Relay operates relay 112 as before.

circuit merely dismissed.

by associating the district selector with other identification circuits.

l Vhatis claimed is:

1. In a telephone exchange system, a plurality of telephone lines, a plurality of correspondingly designated substations on each line, a meter for each substation on each line, a plurallty of selectors, a single metering ter- I minal for each line, a called line, means for establishing a connection to said called line under the control of a substation on one of said lines including one of said selectors, a

meter control circuit common to said selectors, means controlled by the response of said called line for connecting said meter control circuit with said selector, said connecting means being eflective to render said control circuit individual to the selector to which it is connected, aset of relays in said control circuit for each designation of said substations, said relays serving to connect the me ters of all similarly designated substations with the metering terminal of the line on whicheach'substation is located, and means responsive to said connecting means for operating the set of relays for the designation of the callingsubstati'on.

2. In a telephone exchange system, telephone lines having a plurality of subscribers substations located thereon, a single metering terminal for each line, a plurality of selector. switches for extenclingsaid line, a called line, 'means responsive to the extension of a call to said called line from one of said substations through one of said selector switches for testing said line and establishing a record in said selector switch of the calling substation, a meter control circuit, means controlled by the response of said called line to associate said meter con- I trol circuit with said selector, means in said meter control circuit responsive to the record in the selector switch for connecting the cor responding meter of all the lines to which saidselector has access to the metering terminal of the line to which each meter is individual,and means under the joint control of said meter control circuit and said selector to operate the meter of the calling substation. 7

3. In a telephone exchange system a plurality of party lines, asingle metering terminal for each line, a meter for each party on said lines, a plurality of selector switches for extending said lines, a called line, means re sponsive to the extension of a call to said called line from one of said substations through one of said selector switches -for establishing a record in said selector switch of the calling substation, a meter control circuit, means controlled by the response of said called line to associate said meter control circuit with said selector, a relay in said control circuit for each party, means to'operate one of said relays in accordance with the registration'in said selector, means under the control of said relay to connect thecorresponding meter of each line with the metering terminal of that line and means including saidcontrolv circuit and said selector for applying metering potential to said calling'line to operate the meter of said calling party. i

4. In a telephone exchange system, individual lines and party lines, a single metering terminal for each line, a selector for extending connections fromsaid lines, means to test calling lines and to set up a registra tion in the selector if the calling line is a party line to indicate the party calling, a meter control circuit common to a plurality of selectors, said control circuit comprising means for connecting a party line meter withthe metering terminal, means responsive to the connection of the meter with the metering terminal for applying metering current to said metering terminal, and means for discriminating between party lines and individual lines to render said current supply means independent of said meter connecting means in the case of individual lines.

1 5. In a telephone exchange system, individual lines and party lines, a single metering terminal for each line, a selector for extending connections from said lines, means to test calling lines and to set up a registration of the party calling ifthe calling line is a party line and no registration if the calling line is an individual line, a meter control circuit common to a plurality of selectors comprising means under the control of the party registration to connect the proper meter with the metering terminal of a calling party line, and means thereupon effective to supply metering current to said metering terminal and other means effective if no registration is set up in the selector to cause the supply of metering'current to the metering terminal of the calling line.

6. In a telephone exchange system, individual telephone lines; party telephone lines havingapluralityofsubstations,a selector, means for extending a connection from one of said 1 lines throughsaid selector, means for establishing a record of the calling substation in the case of lines having a plurality of substations and no record in the case of individual lines, means to prevent the establishment of any record if said record is not correctly established, a meter control circuit, and means in said meter control circuit to discriminate in its operation between individual lines and party lines and means to discriminate bet-ween a no record condition due to the calling line being an individual line and a no record condition due to improper recording.

7. In a telephone exchange system, individual telephone lines, party telephone lines having a plurality of substations, a selector, means for extending a connection from one of said lines through said selector, means for establishing a record of a calling substation in the case of lines having a plurality of substations and no record in the case of individual lines, means to prevent the establishment of any record if said record is not correctly established, a meter control circuit, means in said meter control circuit to dis criminate in its operation between individual lines and party lines and means to discriminate between a no record condition due to the calling line being an individual line and a no record condition due to improper recording, and means under the control of said discriminating means to record the number of times that a no record condition occurs due to improper recording.

establishing a record of a calling substation in the case of: lines having a plurality of substations and no record in the case of individual lines, means to prevent the establishment or" any record if said record is not correctly established, a meter control circuit, means in said meter control circuit to discriminate in its operation between individual lines and party lines and means to discriminate between a no record condition due to the calling line being an individual line and a no record condition due to improper recording, means under the control of said discriminating means to record the number of times that a no record condition occurs due to improper recording, and manual means to render said discriminating means efiective to indicate the selector on which the record was improperly established.

9. In a telephone exchange system, a plurality of party lines, a meter for each party on each line, a plurality of district selectors for extending said lines, a plurality of identification circuits common to said district selectors, a called line, means to establish a connection from a calling line to said called line by means of oneof said district selectors, means in said district selector responsive to the establishment of said connection to cause the association of one of said identification circuits with said district selector, means in said identification circuit to test the calling line and to set up a registration in the district selector of the calling party, means effective following the establishment of such record to disconnect said identification circuit from said district selector, a meter control circuit, means controlled by the response of said called line to associate said meter control circuit with said district selector, a relay in said control circuit for each party, means to operate one of said relays in accordance with the registration in the district selector, a single metering terminal for each line, means under the control of said relay to connect the corresponding meter of each line with the metering terminal of that line, and means including said control circuit and said district selector for applying metering potential to the terminal of the calling line to operate the meter of the calling party.

In witness whereof, we hereunto subscribe our names this 28th day of May, 1929.

WARREN W. CARPENTER. LEWIS H. JOHNSON.

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