US2351551A - Telephone system - Google Patents

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US2351551A
US2351551A US489013A US48901343A US2351551A US 2351551 A US2351551 A US 2351551A US 489013 A US489013 A US 489013A US 48901343 A US48901343 A US 48901343A US 2351551 A US2351551 A US 2351551A
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relay
over
contacts
conductor
circuit
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US489013A
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Charles F Seibel
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AT&T Corp
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Bell Telephone Laboratories Inc
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M15/00Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
    • H04M15/04Recording calls, or communications in printed, perforated or other permanent form

Description

June 13, 1944. c. F. SEIBEL TELEPHONE SYSTEM 10 Sheets-Sheet 1 Filed May 29. 1945 -&
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A TTORNEV 5 June 13, 944- c. FISEIBEL' 2,351,551
TELEPHONE- SYSTEM Filed May 29, 1943 10 Sheets-Sheet 4 lNVENTOR C. E SE/BEL A TTOPNE V June 13, 1944. c. F, SEIBEL TELEPHONE SYSTEM Filed May 29, 1943 10 Sheets-Sheet 5 I I'll:
/NVE/VT C. ESE/BEL y ATTORNEY Filed May 29, 1943 10 Sheets-Sheet 6 E nun DUDE] D [IUD 3 m m m U U U //v l/ENTO C. E SE/BEL A TTORNEV June 13,1944. c. F. SEIBEL TELEPHONE SYSTEM Filed May 29, 1945 10 Shets-Sheet 7 //v l/ENTOR C. E SE/BEL QG Wm 26 m6 A TTORNEV kmiu 9k June 13, 1944. c, s B L TELEPHONE SYSTEM //Vl EN7'OR C ESE/BEL ATTORNEY June 1944 c. F. SEIBEL 2,351,551
TELEPHONE SYSTEM 10 Sheets-Sheet 9 Filed May 29, 1943 FIG. 9
//v VENTO'R CJ-T SE/BEL Y eam ATTORNEY June 13, 1944. c. F. SEIBEL TELEPHONE SYSTEM Filed May 29, 1943 10 Sheets-Sheet 10 QMQ /NVEN7'0R c. ESE/BEL ATTORNEY Patented June 13, 1944 TELEPHONE SYSTEM Charles F. Seibel, Glen Rock, N. .I., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application May 29, 1943, Serial No. 489,013
4 Claims. (Cl. 1797.1)
which are not so remotely located since the re- 1 motely located offices must be reached over long interoflice trunks which are expensive to install and maintain and it is not equitable to the operating company to provide service to all points in the exchange area at the same basic rate. Furthermore it is not equitable to the operating company that for a basic charge, the subscriber shall be enabled to hold an established connection indefinitely. Both automatic charging in accordance with the zone of the exchange area into which a connection is extended and in accordance with the elapsed conversational period have been heretofore accomplished and whereby the charges for overtime periods of conversation may be made in accordance with the zone into which the connection has been extended and on a different basis than the charges for the initial period of conversation.
It has hereinbefore been difllcult to apply this method of charging to exchange systems employing dial switching apparatus of the step-by-step type since in such systems it is customary to connect the message register of each message rate subscribers line in parallel with the line cut-oil relay and to operate such message register to charge for an established connection by the application of a higher or booster potential to the sleeve conductor of the calling line to operate the message register following the response of the called subscriber. It thus becomes very difficult to operate the message register more than once for any call and therefore in ofiices of this type the repeated operation of a message register in accordance with the zone into which the established connection has been extended and in accordance with the number of'unit periods of conversation, becomes a very difficult problem to solve.
With this problem in mind, it is the object of the present invention to provide a solution therefor which will enable zone and overtime call charging to be applied to existing oflice areas of the step-by-step type with a minimum alteration in the existing central office line and switching equipment. It is, of course, to be understood that the invention is equally applicable to other types of systems.
It has heretofore been proposed to equip office areas of the step-by-step type with equipment whereby subscribers may establish short haul or so-called AB toll calls by dialing, thereby eliminating the services of the toll operator on such calls. To accomplish this it has been proposed to provide facilities for automatically printing on a toll ticket all of the information which may be required for ticketing or billing such calls to calling subscribers,.that is, the calling and called subscribers line identification, the time and date that the call was made, the elapsed time of the conversation and such other data as may be required. A system of this type is disclosed in the application of J. W. Gooderham, Serial No. 448,782, filed June 27, 1942.
In this system in response to the dialing of one or more of the ofllce code digits or letters of a wanted line number, a toll ticketing trunk is seized whereupon an idle sender common to a plurality of ticketing trunks is associated with the trunk over a trunk finder. The seized sender then proceeds to associate itself over a senderidentifier-connector with an idle calling line identifier and the seized identifier then proceeds to associate itself directly with the seized trunk over an identifier trunk connector after which it proceeds to identify the calling line and to register the digits identifying the ofllce and number of the calling line. The identifier, with the assistance of apparatus in the trunk and dial responsive registers in the sender, also proceeds to reconstruct the ofilce code digits of the wanted line dialed by the calling subscriber and to register such oflice code digits. With the office code digits of the called line ofllce thus registered, the identifier operates the proper one of a plurality of route relays, individualized to the oiiices of the toll area, for enabling the sender to control the completion of the connection to the wanted called ofiice and to the wanted line therein. With the called oflice route relay operated, the identifier is also enabled to determine the rate to be charged for the initial period of conversation. Each ticketing trunk of this system is also provided with register switches which are advanced periodically following the response of the called subscriber and until the termination of the conversation to register the elapsed time of the conversation, which elapsed time is printed on the toll ticket as one of the items from which the charg for the toll call may be determined.
From the foregoing brief description of the automatic ticketing system, it will be seen that the apparatus thereof affords a basis for enabling zone and overtime charging by message registers, that is the determination of the charge rate in accordance with the zone of the called line and the elapsed time of conversation. In accordance with the present invention, this automatic ticketing equipment has been so modified that not only is it available for performing its automatic ticketing function on short haul toll calls, but is also available for handling calls from subscribers lines having message registers and for charging for calls on a zone and overtime basis. On any zone call requiring the operation of calling line message registers, a trunk is seized and if the trunk has access to several offices in a plurality of zones, it causes the association of an idle sender therewith over a trunk finder whereupon a calling line identifier becomes connected with the sender and the trunk in the manner previously described. The identifier then proceeds to reconstruct the ofiice code digits of the wanted line dialed by the calling subscriber and to operate a zone relay in the trunk corresponding to the zone called .as determined from the called ofllce code. The identifier is then dismissed without identifying the number of the calling line.
The trunk is provided with a timing circuit which is started upon the response of the called subscriber and continues in operation until the conversation is terminated. During the initial and each overtime period of conversion the timing circuit causes the identifier to become associated with the trunk and to identify the calling line. In response to each identification of the calling line, the identifier selects the register of the calling line over the connector relays of the thousands number circuit, and tens group connector relay and units register relay of the identifier operated during the identification of the calling line and operates such register. in accordance with the zone, initial and overtime registrations in the trunk. The invention is an improvement over the system disclosed in the copending application of W. H. Matthies, Serial No. 490,568, filed June 12, 1943, in that no additional message register connector is required.
The invention having been described in a general manner, reference may now be had to the following detailed description thereof taken in connection with the accompanying drawings in which:
Fig. 1 shows schematically in the upper portion thereof, a line finder and selector switches over which lines of a calling omce may establish connections to a charging trunk shown in Figs. 4 and in the central portion thereof one of the ten thousands transformer coils and the associated hundreds transformer coils of the thousands number circuit serving the ofllce in which the calling line terminates and common to a plurality of calling line identifiers and in the lower portion thereof a group of hundreds connector relays having access to the corresponding hundreds groups of lines of one of the thousands p Fig. 2 shows in the left portion thereof two of the ten groups of thousands connector relays of the thousands number circuit and in the right portion thereof two of the tens transformer coils for identifying the tens group digits of the calling line, the units identifying pads of one of the identifiers and one of the switching relays of an identifier;
Fig. 3 shows one of the identifier-trunk connectors for connecting an identifier seized by a sender with the trunk of a group of one hundred trunks which has been connected to the sender;
Figs. 4 and 5, taken together, show a complete zone and overtime charging trunk including a digit register, zone register relays and an elapsed time measuring switch;
Fig. 6 shows a trunk finder individual to the sender, portions of which are disclosed in the right portion of Fig. 11;
Fig. 7 shows a sender-trunk-connector for connecting any seized sender with the trunk which has seized the sender;
Figs. 8 and 9, the portion of Fig. 10 to the left of the dot-dash line and the right portion of Fig. 2 previously referred to show in schematic form such portions of the apparatus of an identifier as are necessary to an understanding of the invention; Fig. 8 showing in the right portion thereof a switching relay and in the left portion thereof amplifier and detector circuits connecttain control relays of the identifier, in the central portion thereof a sender-identifier-connector for associating a sender seized by a trunk with an idle calling line identifier, in the right portion thereof such elements of a sender as are necessary to an understanding of the invention and in the lower portion thereof message register control relays; and
Fig. 11 is a chart showing how the several figures of the drawings should be arranged to disclose the complete invention.
The line finder llll schematically illustrated in Fig. 1 is of the well-known step-by-step type havin two brush sets one of which has access to an upper bank of terminals in which one hundred lines terminate and the other of which has access to a lower bank of terminals in which a second one hundred lines terminate. Each group of two hundred lines is accessible from a subgroup of line finders an idle one of which is started upon the initiation of a call from any line of the group. The selector switche I02, Ill! and I schematically disclosed in Fig. 1 are also of the well-known Y step-by-step type being directively operable in response to dial impulses to establish connections to charge trunks over which connections may be further extended to subscribers lines terminating in other oillces of the near-by area or to establish connections to toll ticketing trunks over which connections may be further extended to subscribers lines terminating in offices of the near-by toll area. The trunk finder 600 of F18. 6 is of th double brush step-by-step type.
The thousands number circuit disclosed in part in Figs. 1 and 2 is identical with the similar circuit disclosed in full in the Gooderham application hereinbefore referred to. The sender, only a few relays of which are disclosed in the right portion of Fig. 10 is substantially identical with that disclosed in full in the Gooderham application except that two relays i036 and IBM have been added together with associated circuit connections for enabling the sender to function properly on calls requiring zone and overtime message register control. The digit register 400 of the charging trunk of Figs. 4 and 5 is of the rotary stepby-step type which is advanced step-by-step in response to the dialing of an impulse series by the stepping magnet 40I and is restored to normal by the operation of the release magnet 402. The off normal contact set 500 of Fig. 5 is operated in response to the movement of the brush shaft of the register 400 one step oil-normal. The elapsed time switch 550 of Fig. 5 is of the type whose brushes are advanced step-by-step in response to the energization and deenergization of the stepping magnet 55I and advanced to normal in a restoring movement under the control of the stepping magnet.
The sender-identifier-connector I050 of the Fig. 10 is identical with that disclosed in full in the Gooderham application except that provision is made for the extension of two control conductors from the identifier to the sender for use in connection with the added relays I036 and IOI of the sender. The sender-trunk-connector of I Fig. 7 is one of a plurality effective to associate ing trunk. These connector circuits are identical with the corresponding circuits of the Gooderham application. The identifier-trunk-connector of Fig. 3 is one of a plurality effective to associate a seized identifier with a calling trunk. One of these circuits would be provided for each subgroup of twenty trunks and one of these circuits is taken for use as determined by the operation of the trunk finder 600 in associating a sender with the calling trunk. These circuits are substantially identical with the corresponding circuits of the Gooderham application except that additional circuit paths are provided thereover for enabling the identifier to transmit zone registration information to and from the trunk with which the identifier is associated.
To enable a clearer understanding of the invention and the mode of its operation, the manner in which a call from the calling line I00 of Fig. 1 to a called line in another zone of the exchange area will now be described. It will be assumed that the subscriber whose substation is indicated at I00 desires to secure a connection with a subscriber's line whose directory number is assumed to be MAR-1345. When the subscriber removes his receiver from the switchhook, an idle line finder, for example, line finder IN is started in the well-known manner to hunt for the calling line and to connect it with the first selector switch I02 paired with such line finder, whereupon the calling subscriber receives the usual dial tone to indicate that he may then proceed to dial the digits of the directory number of the wanted line. It will be assumed that in response to the dialing of the first ofiice code letter M, the second oflice code letter A and the third ofllce code letter R, the first, second and third selector switches I02, I03 and I04 are operated and a connection is thereby established over the conductors I05, I06, and I01 of an idle trunk I08 to the trunk apparatus disclosed in Figs. 4 and 5.
Upon the seizure of the trunk a circuit is established from ground (not shown) at the third selector switch I04 over sleeve conductor I01 through the lower winding of sleeve relay 408 of the trunk, over the upper normal contacts of test jack 409, through the winding of relay 0 to battery, and in parallel with the winding of relay 4I0 over the armature and back contact thereof and through resistance 4| I to battery. Relay 408 operates from the low resistance battery thus supplied; prepares a locking circuit over its upper winding .and uppermost front contacts; shortcircuits its lower winding and prepares a circuit over its lower front contact for apurpose to be later described. Relay 4I0 also operatesand re moves resistance 4 from the parallel connection with itswinding.
As soon as the talking circuit is cut through over the brushes of the selector switches, a circuit is established from ground through the upper winding of line relay 4I2 over the lower No. 2 back contact of relay 4I3, the upper No. 2 normal contacts of relay 4, tip conductor I05 of the trunk, tip brushes of the selector switches I04, I03 and I02 and line finder IOI over the calling line loop through the substation I00, thence returning over the ring brushes of the line finder IM and selector switches I02, I03 and I04, ring trunk conductor I06, the lower No. 2 normal contacts of relay 4, the upper No. 2 back contact of relay 4I3 through the lower winding of relay M2 to battery. Relay 4I2 thereupon operates closing over its front contact a circuit for slowto-release relay 4I5 which may be traced from ground over the lower No. 1 back contact of relay 4I3, over the front contact of relay 4I2, through the winding of relay 5 to battery and ground. Relay 4I5 thereupon operates; establishes an obvious circuit for slow-to-release relay 4I6; prepares over its upper No. 1 contact a circuit for the stepping magnet 40I of the digit register 400 and for the slow-to-release relay 4II; connects ground from the lower No. 3 back contact of relay 4I8 over its upper No. 3 front contact and the upper No. 2 back contact of relay M9 to the trunk finder start conductor 420 which is common to ten trunks of the subgroup; establishes a connection from ground and battery through the winding of relay 4I9 over the upper No. 3 back contact of relay 8 and the No. 1 lower front contact of relay 5 to conductor 42I to mark the trunk as calling so that the started trunk finder will stop on the terminals of such trunk, and over its lower front contact prepares a circuit for the transfer relay 4I3. Relay 6, upon operating, completes the locking circuit of sleeve relay 408 which may now be traced from battery through the upper winding and over the upper contacts of relay 408, over the upper normal contacts of jack 409, over the lower No. 2 back contact of relay 422 to ground on the lower front contact of relay 4| 6 to hold relay 408 operated and over the sleeve conductor I01 of the trunk to hold the selector switches I02, I03 and I04 and the line finder IOI from releasing.
When relay 2 releases due to the opening of the dialing circuit for the first impulse of the thousands numerical digit 1 of the wanted line number, the circuit for magnet MI and the circuit for relay 4II previously prepared by the operation of relay 4I5 are completed from ground over the lower No. 1 back contact of relay 4I3 over the back contact of relay M2, the upper'No. 1 front contact of relay 5, conductor 423, the lower normal contacts of off-normal contact set 500 of the digit register 400, the lower normal contacts of relay 4" to battery through the winding of relay 4" and in parallel therewith to battery through the winding of stepping magnet 40I its inner upper contacts thereby establishing a circuit from battery through its upper winding over such contacts, the lower contacts of rotary magnet 6I8, contacts of relay 6| l to ground over the lower contacts of relay 609. Both of its windings being now energized, relay 620 fully operates to extend control conductors 425 to 43l, inclusive, of the trunk over brushes 62l to 621, inclusive, of the trunk finder and the upper Nos. 4 and 6 and lower Nos. 1 to 4 contacts of relay 620 to conductors 628 to 634, inclusive, extending to the sender; to cause the operation of relay 608 in a circuit extending from ground over the offnormal springs 6I6, the lower No. 5 front contact of relay 620, through the lower winding of relay 808 to battery and ground; to connect sender conductor 635 over its upper No. 5 contacts and brush 636 to conductor 6 which is multipled to corresponding bank terminals in the same vertical row of the upper finder bank; to open at its lower No. 5 back contacts another point in the circuit of release magnet 6|! and to prepare a locking circuit for itself over its upper No. 1 front contact which will be effective following the operation of relay 608.
Relay 608, upon operating, extends trunk conductor 42l over terminal H3 and brush 6I8, the upper No. 2 contacts of relay 620 and the upper front contact of relay 608 to conductor 6! extending to the sender; completes the locking circuit of relay 620 extending from battery through the upper winding and upper No. 1 contacts of relay 620, over the middle upper contacts of relay 606 to ground on conductor 6I0; transfers at its inner upper contacts the in-start conductor 606 from the winding of start relay 603 to the out-start conductor 642 and through its upper winding to battery at the upper back contact of relay 681; at its inner lower back contact removes battery from the windings of relays 6H and M4 and from the vertical magnet 6 I2 and'at its upper front contact shunts the upper winding of relay 6. Relays 6H and 6 now release and relay 609, being slow to release, releases after an interval sufficient to allow ground to be applied to conductor H at the sender to hold relay 620 and relay 4 I 9 of the trunk operated.
When relay 6 releases the continuity of the out-start conductor 642 is established at its lower contacts whereby if a second trunk in the same subgroup should be in a calling condition, ground placed on the in-start conductor 606 will be effective to start the second trunk finder of the same subgroup of finders if it is idle over a circuit extending from conductor 606, over the middle normal contacts of test jack 601, the inner upper front contact of relay 608, the lower normal contacts of relay 6, conductor 642, the inner normal contacts of test jack 601, the middle normal contacts of test jack 60'! associated with the second trunk finder of the same trunk finder group, thence over the upper normal contacts of relay 608' to the start relay of such second finder corresponding to relay 609. Had such second finder oi. the subgroup of finders been busy and consequently relay 606' had been operated, the start circuit thus traced would be extended over the front contacts of this relay, the lower normal contacts of test jack 601", the middle normal contacts of test jack 601", associated with the first finder of the next subgroup of finders, serving as second choice finders to the last subgroup of trunks and first choice to another subgroup oftrunks, thence over the normal contacts of relay 608", of such finder to the start relay thereof.
In a similar manner the in-start conductors 606, 636, 639, etc. of the ten trunk subgroups may be extended to start trunk finders in the allocated first choice subgroups of finders or in other choice subgroups of finders.
. When the trunk finder seized the terminals of the calling trunk and completed the circuit previously traced from battery through the winding of relay 9, relay 9 operated and locked itself over its No. 1 upper front contacts directlyto ground applied over conductor 42I from the trunk finder and at a later time from the sender. As soon as relay 4I'I releases following the completion of the registration of the impulse series in r the digit register 400, a circuit is completed for transfer relay 4I3 which maybe traced from battery through the winding of such relay over the lower No. 2 contacts of relay 9, over the No. 2 front contacts of relay M5 and the upper back contact of relay 4" to ground over the upper alternate contacts of off-normal contact set 600. Relay 413 thereupon operates and looks over its upper No. 1 contacts, conductor 432, the inner upper back contact of charge relay 50 I, conductor 433 to ground over the lower No. 1 contacts of relay 9 and to ground over the upper No. 1 contacts of relay 4 when relay 4 is later operated. With relay 3 operated, the dialing circuit previously traced over the calling line loop and through the windings of relay 2 is disconnected from the windings. of such relays and transferred to the connected sender. Remy 2 now releases followed by the release of slow-to-release relay 4I5, but with relay 4I9 now operated, relay M6 is held operated over a circuit extending from battery through its winding, over the upper No. 3 contacts of relay 9 to ground.
Should an idlesender not be connected to the trunk before the second train of impulses is received in the trunk, relays M3 and 419 will not have operated and therefore when relay 2 releases on the first impulse of this digit series, a circuit will be established from ground over the lower No. 1 back contact of relay 3, back contact of relay 2, the upper No. 1 contacts of relay 4I5, the lower alternate contacts of off-normal contact set 500, over the inner upper back contact of relay M1 to battery through the winding of relay 4I8. Relay 8 thereupon operates, looks over its upper No. 1 contacts to ground over the inner lower contacts of relay 4I6; establishes an operating circuit for the cutthrough relay 4 I 4 extending from battery through the winding of such relay over the upper No. 2 contacts of relay 8 to round at the inner lower contacts of relay 6, which relay looks over its lower No. 1 contacts to ground over inner lower contacts of relay 416; prepares a path busy tone circuit over its lower No. 1 contacts; removes starting ground at its lower No. 3 back contact from the trunk finder start conductor 420 and at its upper No. 3 back contact disconnects marking battery through the winding of relay 9 from conductor 42I. With relay 4I4 operated, the windings of relay 2 are disconnected from the calling line loop and the loop is extended over the tip conductor I05, the upper No. 2 alternate contacts of relay 4, conductor 434, the upper left winding of repeating coil 502, the upper back contact of reversing relay 503 to ground through the lower winding of supervisory relay 604 and over the ring conductor I06, the lower No. 2 alternate contacts of relay 4, conductor 435, through the lower left winding of repeating coil 602 to battery, over the lower back contact of relay 000 and through the upper winding of relay 504. Relay 004 operates and closes a circuit for holding relay 4I0 operated following the release of relays M2 and M5 which occurs upon the operation of relay 4, which circuit may be traced from battery through the winding of relay 4I0 over conductor 400, the contacts of relay 504 and conductor 401 to ground over the upper contacts of relay 0. Relay 004 is thus under the control of the calling subscriber to control the release of the trunk. The paths busy circuitis now completed from the source of tone current 400 over the lower No. 1 contacts of relay 8 over the tip trunk conductor Iv and the calling line loop returning over the ring trunk conductor I00 and thence as traced to battery through the upper winding of supervisory relay 504.
It will be assumed, however, that an idle sender is attached to the trunk prior to the receipt of the second impulse series in the trunk. Prior to the operation of transfer relay 0, the loop circuit is established from battery through the lower winding of dial impulse response relay I002 of the sender, over conductor 000, the upper No. 3 contacts of relay 020 and brush 020 of trunk finder 000, conductor 421, the upper No. 3 'normal contacts of transfer relay 4I0, over the lower No. 1 back contact of relay 400, the lower No. 2 back contact of relay 0, through resistance 440 over the lower No. 3 normal contacts of relay 4I0, conductor 420, brush 022 and the upper No.4 contacts of relay 020 of the trunk finder 000,
conductor 020 and thence to ground through the upper winding of relay I002. Relay I002 operates over this circuit and establishes a circuit from ground over its contacts, the back contact of relay I000 and through the winding of relay I004 to battery and relay I004 thereupon operates and locks through resistance I005 and over its front contact to ground at the front contact of relay I002 and at its upper front contact closes an obvious circuit for slow-to-release relay I000. Relay I000, upon operating, establishes obvious circuits for off-normal relays I000 and I000, relay I006 upon operating connecting ground to conductor M0 to replace the ground applied thereto by relay 500 of trunk finder 500 which latter relay releases after the trunk finder has found the calling trunk. Relay I080 upon operating connects ground to the off-normal ground conductor I001.
After the operation of transfer relay 0, conductor 425 of the loop circuit previously traced through the windings of relay I002 is connected over the lower No. 3 alternate contacts of relay 3 and the upper No. 2 normal contacts of relay 4I4 to the tip conductor I05 and conductor 421 is connected over the upper No. 3 alternate contacts of relay 4I0, over the lower No. 2 normal contacts of relay 4 to the ring conductor I00 whereby relay I002 is placed under the control of the calling subscriber. In response to the dialing of the hundreds, tens and units digits of the wanted line number, dial impulse responsive relay I002 now responds to cause the registration 'of the hundreds, tens and units digits 3, 4 and 5 in registers (not shown) of the sender in the manner fully described in the Gooderham application hereinbefore referred to. After the first digit has been received in the sender, an idle identifier, such as is disclosed in part in Figs. 8 and 9, the right portion of Fig. 2 and the left portion of Fig. 10, is associated with the sender by a senderidentifier-connector I050 and the identifier is asaociated with the trunk by a trunk-identifierconnector.
Upon its-seizure, the identifier is informed that the calling trunk is located in a particular subgroup of twenty trunks by a circuit extending from ground placed on conductor "0 by the sender, over the upper middle contacts of relay 000, the upper No. l contacts of transfer relay 020, conductor 040, contacts "II of sender-v identifier-connector relay I000 to battery through the winding of relay I000 in the identifier. Relay I008 thereupon operates. Start relay I0l0 of the identifier is also operated in a circuit established over contacts I050 of the sender-identifier-connector relay I050 and establishes a circuit from battery through resistance IOI0 over its No. 2 contacts, conductor IN I, conductor 005, over the upper No. 5 contacts of relay 020 and brush 000 of trunk finder 000, conductor 04I, contacts I054 of sender-identifierconnector relay I050, contacts of relay I000, conductor IOI2, through the winding of lock-out relay 000F, allocated to the first identifier and to the identifier-trunk-connector having access to the Nos. 0 and 9 subgroups of trunks, over the inner upper normal contacts of similar lock-out relays 000I and 000L allocated to other identifiers to ground. Relay 000F operates, locks over its upper inner alternate contacts to ground, establishes an operating circuit for the multicontact relay 00IF from ground through the winding of such relay over the inner lower front contact of relay 000B, through resistance 002 to battery, and establishes a circuit from battery through resistance 003, over its middle upper front contacts, conductor IOI0, over the No. 1 contacts of identifier start relay IOI0, contacts I055 of the sender-identifier-connector relay I050, conductor 032, over the lower No. 2 contacts of relay 620 and brush 625 of the trunk finder 000, conductor 429, through the windings of polarized connector relay 422 of the trunk, through resistance 445 to ground over the lower No. 3 contacts of relay 4I0. Multicontactrelay 00IF of the identifier-trunk-connector and relay 422 of the trunk finder both operate. Relay 00IF extends a plurality of control conductors from the calling line to the identifier.
Polarized relay 422 is energized in such a manner as to operate its upper contacts, and establishes a circuit from battery through resistance 000, over the inner lower No. 2 back contact of relay 002, conductor IOI4, the No. 4 contacts of relay I009, conductor IOI5, the No. 22 contacts of identifier-trunk-connector relay 00IF, conductor 004, the upper No. 2 contacts of relay 422, brush 424 of digit register 400, which it has been assumed was advanced to the No. 2 terminal of its arc, over a conductor of the group 442, the No. 11 contacts of relay 00IF, conductor 005 of group 000, extending to ground through the winding of one of a group of trunk code relays (not shown) in the identifier, thereby operating one of such relays. The thousands digit dialed by the calling subscriber is thus transferred from the register 400 of the trunk to the trunk register of the identifier. Relay 422 also establishes a circuit from battery through resistance 004, over the lower No. 3 back contact of relay 902, conductor IOI0, the No. 3 contacts of relay I009, conductor IOI1, the No. 23 contacts of relay 00IF, conductor 001, the upper No. 3 contacts of relay 422, the lower contact of the sleeve relay of the trunk appearance, on the banks of the selectors in order that the identifier may reconstruct the digits which may have been dialed to reach the trunk.
' In the present case it has been assumed that the subscriber dialed all three of the code digits or letters of the called line number to reach the trunk and that therefore sleeve relay 400 was'operated indicative of the fact that the trunk was seized over a third selector bank appearance thereof. With relay 400 operated,"the connection of battery over the upper No. 3 contacts of relay 422, completes a circuit over the lower contacts of relay 400, code'conductor 440, cross-connected over the rack 508 to-conductor 300, over the No. 59 contacts of relay 30IF, conductor IOI through the winding of route relay IOI9 to ground. Route relay IOI0, upon operating, causes the reconstruction of the called oillce code digits dialed by the calling subscriber and their registration in the associated sender to enable the sender to control the extension of the desired connection from the charging trunk to the office in which the wanted line terminates; causes the transfer of the thousands digit registered in the trunk register of the identifier to a register in the sender whereby the sender may have complete information concerning the numerical designation of the wanted line to enable it to complete the establishment of the connection to such wanted line and transmits such other information to the sender as may be required by the sender in handling the call, all in the manner fully described in the Gooderham application hereinbefore referred to.
In addition relay 422 of the trunk establishes a circuit from ground over its upper No. 1 contacts, conductor 3I0, over the No. 21 contacts of relay 30IF', conductor I020, through the winding of relay I02I to battery and ground whereupon relay I02I operates as an indication to the identifier that the trunk which has been seized is one of a group which does not serve automatic ticketing calls and that therefore no toll ticket is to be printed. Relay I02I, upon operating, establishes a circuit from ground over the upper No. 4 back contact of relay 902, conductor I022, contacts of relay I02I, contacts I052 of the sender-identifier-connector relay I050 to battery and ground through the winding of relay I023 ,of the sender, which relay upon operating looks over its inner lower contacts to the offnormal ground conductor I001 and informs the sender that no ticket is to be printed for the call which it has been selected to serve.
As soon as the sender has received all of the information required for controlling the establishment of the connection, a control circuit is established which may be traced in part over conductor 633, the lower No. 3 contacts of relay m and brush 526 of the trunk finder son and conductor 430 to the tip conductor 444 of the outgoing trunk and over conductor 534, the lower No. 4 contacts of relay 620 and brush 521 of the trunk finder 500 and conductor 43! to the ring conductor 445 of the outgoing trunk. When the sender has complgted the establishment of the connection, the end of pulsing relay I024 of the sender operates in the manner fully described in the Gooderham application hereinbefore referred to and establishes a circuit that may be traced from ground over its contacts through both windings of relay I025 in series, thence as traced over conductor 632, through the windings of relay 422 of the trunk and through resistances 445 and 441 to battery and ground. Relay 422 operates in this circuit in such a manner as to close its lower contacts but relay I025 of the sender does not operate. vRelay 422., upon operating, extends conductor 42! over its lower No.1 -1 contacts,
through the winding of cut-throughirelay 4l4,
over the circuit just traced through thewindings of relay I025 of the sender. Relay I025. now operatesbut relay 4I4 does not operate and relay I025 upon-operating causes the-operation of rea lay I025 which locks over its uppercontact to ground on the oil-normal ground conductor I001 and closes a shunt-around the upper winding of relay I025. With the-upper winding of relay I025 shunted, cut-through relay 4I4 of the trunknow operates and locks over its inner lower No. 1 contacts to ground over the lower inner contacts of relay 5.
Relay 4, upon operating, cuts through the calling line to the windings of supervisory relay 504 over circuits previously traced whereupon relay 504 operates and establishes a previously traced holding circuit for relay 5. Relay 4I4 also establishes a circuit toward'the called=subscribers line which may be traced in part from tip conductor 444 over the upper No. 3 contacts of relay 4, conductor 440, through the upper right winding of repeating coil 502, through the winding of called supervisory relay 505, conductor 505, the upper No. 4 back contact of relay 4I8, conductor 501, through the lower right winding of repeating coil 502, conductor 449 and the lower No. 3 contacts of relay 4 to ring conductor 445. Relay 505 being polarized does not operate untilthe called subscriber answers.
The identifier having operated the route relay IOI9 in accordance with the reconstructed called ofilce code digits, the route relay in addition to performing the functions previously discussed also establishes a circuit from ground over its contacts strapped over terminals of connecting rack I021 to a conductor of the group I028 extending over contacts of the identifier-trunkconnector relay 30IF to battery through windings of the zone register, relays 5I3' to 5I.$ of the trunk. It will be assumed that the wanted line terminates in the a: zone of the exchange area and that therefore the operation of route relay IOI9 establishes a connection from ground over its contacts strapped over terminals of rack I021 to conductor I029, over the No. 3 contacts of relay 30IF and conductor 3 through the winding of zone register relay 5I3 to battery and ground. Relay 5I3 thereupon operates and locks over its upper No. 1 contacts and conductor 431 to ground over the upper contacts of relay 5. Thus zone register relay 5I3 remains operated throughout the duration of the conversation and until the calling subscriber releases the connection.
The identifier having operated its no-ticketing relay I02I as an indication that no ticket is required and having operated no-ticketing relay of relay I035 which releases in turn releasing the sender-identifler-connector relay I050 to release the identifier which in turn releases the identifier-connector relay 30IF to disassociate the identifier from the trunk.
When the called subscriber answers, the direction of'current flowing through the winding of supervisory relay 505 is reversed whereupon it operates in turn establishing a circuit from battery through the winding of reversing relay 503 which in turn Operates to reverse the connection of the windings of supervisory rela Ill to the calling line for supervisory purposes, and establishes a circuit which is effective upon the next operation of relay Ill when interrupter Ill closes its back contact. This circuitmay be traced from ground over the lower contacts of relay Ill, conductor Ill. the upper No. contacts of relay Ill to battery and ground through the winding of relay erates and locks'over its inner upper front contact and conductor 03 to ground over the upper No. 1 contac of relay lll. It is tol'be noted in this connec ion that relays Ill and"! serve as interrupter relays alternately operated under the control of interrupter Ill, relay Ill being operable over the upper No 6 back contact of relay Ill when relay III is unoperated and the interrupter closes its back contact and relay Illbeing operable over the upper No. 6 back contact of relay Ill when relay Ill is unoperated and the interrupter closes its front contact. Relays Ill and Ill and interrupter Ill are common to a subgroup of ten trunks.
Relay Ill upon operating opens the holding circuit of transfer relay lll and establishes a circuit for relay Ill extending from battery through the upper winding ofsuch relay, over the upper No. 4 back contact of overtime relay III, over the normal terminal of the arc engaged by brush III of the elapsed time switch IIl to ground over the lower No. 3 front contact of relay Ill. Relay Ill upon operating establishes the circuit of magnet IIl, extending over its lower No. 2 contacts and conductor Ill to ground over the upper No. 4 contacts of relay lll, closes a loop over its lower No. 4 contacts and conductors III and Ii! across conductors Ill and 421 to hold the sender relay llll operated and establishes a circuit from ground over its lower No. 3 contacts, conductor llI, brush Ill and the upper No. 6 contacts of relay I2l of the trunk finder Ill, conductor Ill, over the inner upper normal contacts of relay llll through the winding of relay illl and through resistance llll to battery and ground. Relay llll thereupon operates and establishes a circuit from battery through resistance llll over its upper contacts over the normal contacts ofrelay Hill and the upper back contact of relay .llll to ground through the winding of relay lllI which upon operating causes the operation of sender-identifier-connector relay llIl to associate an idle identifier with the sender. The identifier then proceeds to connect itself over the identifier-trunk-connector relay lllF with the calling trunk. Relay llll upon operating and with relay llIl operated, establishes a circuit from ground over its lower contacts and contacts llIl oi. relay "II to battery through the winding of relay llll of the identifier.
It will be recalled that relay 422 of the trunk has been so operated as to close its lower contacts and in such operated position holds its upper contacts in their normal condition. Relay 422 is held in such position over a circuit extending from battery through resistances 1 and I over the lower No. 1 contacts and through the windings of lay lit to ground over the inner lower contacts of relay lll. Consequently, no circuits are effective to cause the identifier to reconstruct the called ofilce code or to operate the no-ticketing relay llll as previously described. 5 Since the no-ticketing relay llll of the identifier his not operated, the identifier proceeds to identify the calling line in the manner fully described in the Gooderham application hereinbefore referred to. For this purpose signaling current from the 270-cycle source llll is applied over conductor llll, the No. contacts of identifier-trunk-connector re-' lay lllF, conductor lIl, over the lower No. 2 contacts of relay 422, over the upper normal contacts of test Jack 409, the upper contacts of trunk sleeve relay lll, trunk sleeve conductor lll, thence over the sleeve circuit of the connection established from the calling line including the sleeve brush lllof the line finder Ill, sleeve conductor ill of the calling line, conductor Ill through resistance III and condenser ill to a terminal strip ill in the cross-connecting rack relay l2: and the lower No. 1 front contact of re- In the manner fully described in the Gooderplifier-detector circuits lll to Ill, inclusive, are first associated with the secondary windings of the thousands coils of the thousands number circuit appertaining to the calling ofllce and with the thousands group register relaysin the identifier. It will be assumed that the numerical or directory number of the calling line is 9099. The signaling current from the source lll l will therefore flow through the primary winding of the No. 0 hundreds coil lHTl to ground through the primary winding of the No. 9 thousands coil lTHT and will be induced into the secondary winding of coil lTHT to cause the response of the amplifier-detector circuit lll and the operation of a relay in the thousands group register circuit of the identifier. In response to the operational this relay a circuit is established over a conductor of cable THGR through the winding of the lock-out relay lllF of the No. 9 thousands numbervcircuit allocated to the first identifier assumed to be seized for use, thence over the lower normal contacts of the look-out relays H91. and IllL allocated to other identifiers, thence to ground if no other identifier has at the time seized the same thousands number circuit and its lock-out relay is not therefore operated. Relay lllF upon operating locks to ground over its lower contacts'and establishes an obvious circuit for the No. 9 thousands group connector relay 239! which thereupon operates.
After the thousands group connector relay 2391" has been operated, the identifier proceeds in the manner fully described in the Gooderham application to associate the secondary windings of all of the hundreds transformer coils lHTl to lHTl of the No. 9 thousands group with the amplifier-detector circuits lll. to 909 over contacts of the operated thousands group relaylllF and the amplifier-detector circuits are also associated with the hundreds group register circuit of the identifier. It having been assumed that the calling line is located in the No; 0 hundreds group, the signaling current applied to the sleeve conductor of the calling line will be applied to the primary winding of the hundreds transformer coil lHTl and will be induced into the seconda y winding of such coil and applied to the input side of the amplifier-detector circuit 800. This circuit will thereupon respond and cause the hundreds group register to register the hundreds digit 0.
operated to register the hundreds digit 0, a circult is established by such relay over a conductor of cable HGR over the No. contacts of the thousands group connector relay 299F and over conductor I I 9 to ground through the winding of hundreds group connector relay I90. Relay I90 opcrates over this circuit to connect the sleeve conductors of the one hundred lines of the No.0 hundreds group over its contacts and the contacts of the operated thousands group connector relay 2391 to the tens transformer cOlls shown in the right portion of Fig. 2. Over its lower contacts relay I90 also establishes a circuit over conductor I I9, over the No. 15 contacts of relay 2991' and conductor 204 to prepare the tens group register circuit for operation.
As previously stated, when the hundreds group connector relay I90 operated and with the thousands group connector relay 2391" operated, the sleeve conductors of one hundred lines are extended over contacts thereof and over conductors of cable 205 to the tens group and terminalidentifying circuits of Fig. 2. The one hundred conductors thus extended from the hundred sleeve conductors are grouped in ten groups of ten conductors each corresponding to the ten hundreds groups which have the same tens identification digits. Each conductor terminates in a serially connected condenser and resistance and each group of ten conductors is multipled to one terminal of the primary winding of a tens group transformer coil such as 259, the other terminal of which is connected to ground. The secondary windings of transformer coils 250 to 259, inclusive, are connected over conductors of cable 206 to the input sides of the amplifier-detector circuits 000 to 009, through the operation of a switching relay as fully disclosed in the Gooderham application. It has been assumed that the tens digit of the calling line number is 9 and that the units digit is also 9 and that therefore the signaling current on the sleeve conductor of said line is conducted over contacts of relays I90 and 2991" and conductor 201 of cable 205 through condenser 209 and resistance 209 and the primary winding of the No. 9 transformer coil 259 to ground. This signal current is induced into the secondary winding of coil 259 and is applied over conductors of cable 209 to the No. 9 amplifierdetector circuit 809 resulting in the operation of a relay in the tens group register circuit to register the tens digit 9. With this register relay operated, a circuit is established thereby extending over a conductor of cable TGR, to battery through the winding of the No. 9 tens group connector relay 249.
Relay 249 upon operating connects each of the group of ten conductors of cable 205 connected over the contacts of connector relays 239F and I90, to the sleeve conductors of the ten lines having the same tens digit, to ground through a condenser resistance network. It has been assumed that the calling line has a units digit 9 and that therefore with the signal current applied to the sleeve conductor N0, the current is transmitted over contacts of relays I90 and 2391 conductor 201 of cable 205, over the upper No. 6 contacts of relay 249 to ground through condenser 269 and resistance 219 of the network and through resistance 289 and over contacts of switching relay 210 to the input side of amplifler-detector circuit 909. In response to the signal current, anode relay 029 is operated, thereby causing the operation of register relay M9.
With register relay 8I9 operated a circuit is established over the contacts of switching relay 910 and conductors 931 and 932 through the upper winding of units register relay 9I9. Relay 9I9 thereupon operates and, with relay 943 previously operated, locks in a circuit from ground through its lower winding and inner lower contacts over the upper No. 1 contacts of relay 943 and conductor I to battery through the wind ing of relay I04I. Relay I04I operates in this locking circuit and at its upper contacts prepares the circuit of relay 94I. Since these identification and registration functions are all performed in identically the same manner as described in the Gooderham application, detail circuits by which these functions are carried out have been omitted to simplify the disclosure.
With thousands group connector relay 239E, hundreds group connector relay I90, tens group connector relay 249 and units register relay 9I9 all operated, a circuit over which the message register MR of the calling line I00 may be operated is prepared. This circuit may be traced in part from ground through the winding of the message register MR over the upper contacts of hundreds group connector relay I90, conductor I20, the No. 25 contacts of the thousands group connector relay 2391 conductor 201 of cable 205, the upper No. 6 contacts of the tens group connector relay 249, conductor 933 of cable UR over the inner upper front contact of the units register relay 9I9, over the inner upper back contacts of the other units register relays and over conductor 900 to the lower armature relay M. It is to be noted that this circuit is in large part, that is, up to the contacts of the tens group connector relay 249, the same circuit that was previously used in identifying the units digit of the calling line number.
Charges for calls to different charge zones of the exchange area might, for example, be made on the basis set forth in the following table:
It will be recalled that zone charge relay 5| 3 has been operated in the trunk and that the elapsed time switch is still in its normal position in which it has caused the operation of charge relay SM and the energization of stepping mag net 55L With zone relay 5 I3 operated and prior to the operation of relay I04I, a circuit is established from ground over the upper back contact of relay I04I, conductor I042, the N0. 10 contacts of identifier-trunk-connector relay 30IF, conductor 520, the lower No. 1 contacts of relay 50I, the lower back contact of relay 5I5, the lower No. 2 contacts of relay 5I3 conductor 52I, the No. 1 contacts of relay 30IF, conductor I043 strapped across the connecting rack I021 to conductor I044 and through the winding of slow-to-release relay I010 to battery. Relay I010 upon operatthe message register MR to make one charge. I
Relay I04I upon operating also opens atits upper back contact the previously traced operating circuit for relay I010 which releases after an interval determined by its slow-to-release characteristic, to open the circuit of the message register MR and to open the circuit of slow-to-release relay I01I. After an interval. relay I01I releases thereby reconnecting battery through resistance I040 over its lower back contact, the lower front contact of relay I012, and the lower contacts of relay II to the circuit of message register circuit MR thereby again operating such register to make a second charge. Relay I01I upon releasing also opens the circuit of relay I012 which releases after an interval again opening the circuit of the message register at its lower contacts.
Relay I012 upon releasing also opens the circuit of'relay I010. When relay I010 releases after an interval, it reconnects battery through resistance I040 over the back contact of relay I010. the lower front contacts of relay I014 and over the lower contacts of relay II to the circuit of message register MR thereby again operating such register to make a third charge. Relay I010 upon releasing also opens the circuit of relay I014 which releases after an interval again opening the circuit of the message register at its lower contacts. Relay I014 releases after an interval opening the circuit of relay I010 which also releases after afurther interval and reconnects battery through resistance I040 over its back contact, the upper contacts of relay I010 and the lower contacts of relay "H to the circuit of the message register MR thereby operating such register to make a fourth charge. Relay I010 upon releasing also releases relay I010 which again opens the circuit of the message register. The message register MR has thus been operated four times to charge for the initial five minute period of conversation.
Had the call been to a zone of the exchange area requiring but a single charge for the initial periodythen the circuit previously traced from ground over the back contact of relay I0 and thence over the lower back contact the relay Ill would have been extended over the inner lower contacts of zone register relay I0 assumed to be operated on such a call, over conductor 022,
the No. 7 contacts of relay 00IF, conductor I046.
strapped across rack I021 to conductor I041 and to battery through the winding of relay I010. Therefore when relay I041 operates as previously described, it opens the circuit of relay I041 and battery through resistance I040, over the back contact of relay I010, the upper contacts of relay I 016 and the lower contacts of relay I0, is applied to the circuit of message register MB. to operate such register once during the releasing time of relay I016. Had circuits been established through the operation of other zone register relays Si! or H0 (not shown) of the trunk over either conductor I040 or I040, either relay I012 or relay I014 of the train of charging relays would have been first operated resulting in the operation of the message register MR to make two or three charges for the initial period of conversation.
When relay I016 closes its back contact it establishes the circuit of relay 94! which may be traced from battery through its winding over conductor 001, over the lower back contacts of relay I010 and to ground over the upper front contact of relay I04I. Relay 0 upon operating opens the circuit over which the hundreds connector relay I was operated whereupon such relay releases and also causes the release of relay III? which in turn releases the thousands connector relay 2001". with relays I00 and 0005 released. the thousands number circuit is now restored to its normal position. Relay I010 also closes a circuit from ground over the upper front contact of relay I04I, over its lower back contact, the contacts of relay I000, contact I001 of the sender-identifier-connector relay I 050 to battery through the winding of release relay IOII of the sender, whereupon relay IO0I operates, locks over its upper alternate contacts, conductor 020, the upper No. 6 contacts of relay 020 and brush III of trunk finder 000, conductor 42! to ground over the lower No. 3 contacts of relay II4, closes the circuit of relay I 00I which upon operating opens the circuit of relay I000 to initiate the release of the identifier and closes at its lower contacts the circuit of release relay I000 of the sender to initiate the release of the sender. The identifier-trunk-connector and trunk finder are now both released.
When the sender releases ground is removed from conductor 0I0 thereby releasing relay 020 of the trunk finder and relay 0 of the trunk. With relay 020 released, a circuit is established for release magnet 0" extending from battery through the winding of such magnet, over the lower contacts of oil-normal switch BIG, over the inner lower back contact of relay 0, the lower No. 5 back contact of relay 020, the upper back contact of relay 609 to ground over the upper contacts of oif-norrnal switch 0". When the trunk finder is fully restored to normal, the contacts of switch 0I0 open thereby releasing the magnet 0.
At the trunk when relay 0 releases it opens the previously traced circuit of stepping magnet I of switch 050 whereupon magnet ill releases to advance the brushes one step from normal. When brush 502 leaves the normal terminal of its arc relay 0I4 releases. A circuit is now effective for further advancing the brushes of switch 500 step by step at fifteen second intervals which may be traced from ground over the lower No. 3 front contact of relay IOI, contacts of interrupter M9, brush 500, strapped terminals of the are associated with brush 550, the lower No. 2 back contact of relay 4 through the winding of stepping magnet "I to battery. It will be assumed that the conversation continues for eight minutes and that the initial period of conversation is fixed by the operating company as five minutes. At the expiration of five minutes, brush 552 of the switch will have -been advanced into engagement with the last terminal of its are, thereby completing a circuit from ground over the lower No. 3 front contact of relay 50L brush 552, such are terminal and then through the lower winding of relay 5I4 to battery and ground. Relay 5I4 thereupon operates extending its operating ground over its lower No. 1 contacts and through the lower winding of overtime relay BIS to battery and ground. Relay 5|! now operates and locks itself over its upper winding and upper No. 1 contacts in a circuit extending over conductor 401 to ground over the upper contacts of relay 4 I 6.
Relay 5 upon operating closes a circuit for thev group start relay GIIIL which may be traced
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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428376A (en) * 1943-06-12 1947-10-07 Bell Telephone Labor Inc Time controlled register for automatic telephone systems
US2562717A (en) * 1947-08-22 1951-07-31 Bell Telephone Labor Inc Dialed number recovery circuit
US2580093A (en) * 1947-12-16 1951-12-25 Bell Telephone Labor Inc Call data recording telephone system
US2579729A (en) * 1947-09-04 1951-12-25 Bell Telephone Labor Inc Automatic telephone message accounting system
US2599358A (en) * 1948-10-29 1952-06-03 Bell Telephone Labor Inc Call data recording automatic telephone system
US2614176A (en) * 1950-05-06 1952-10-14 Bell Telephone Labor Inc Electronic induction number group translator
US2675426A (en) * 1950-05-17 1954-04-13 Bell Telephone Labor Inc Electronic induction number group translator
US2688658A (en) * 1947-07-07 1954-09-07 Bell Telephone Labor Inc Call data recording telephone system
US2854517A (en) * 1955-03-28 1958-09-30 Philips Corp Arrangement for identifying calling lines
US2866008A (en) * 1955-02-28 1958-12-23 Gen Telephone Lab Inc Testing apparatus for calling line identifiers

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428376A (en) * 1943-06-12 1947-10-07 Bell Telephone Labor Inc Time controlled register for automatic telephone systems
US2688658A (en) * 1947-07-07 1954-09-07 Bell Telephone Labor Inc Call data recording telephone system
US2562717A (en) * 1947-08-22 1951-07-31 Bell Telephone Labor Inc Dialed number recovery circuit
US2579729A (en) * 1947-09-04 1951-12-25 Bell Telephone Labor Inc Automatic telephone message accounting system
US2580093A (en) * 1947-12-16 1951-12-25 Bell Telephone Labor Inc Call data recording telephone system
US2599358A (en) * 1948-10-29 1952-06-03 Bell Telephone Labor Inc Call data recording automatic telephone system
US2614176A (en) * 1950-05-06 1952-10-14 Bell Telephone Labor Inc Electronic induction number group translator
US2675426A (en) * 1950-05-17 1954-04-13 Bell Telephone Labor Inc Electronic induction number group translator
US2866008A (en) * 1955-02-28 1958-12-23 Gen Telephone Lab Inc Testing apparatus for calling line identifiers
US2854517A (en) * 1955-03-28 1958-09-30 Philips Corp Arrangement for identifying calling lines

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