US3046352A - Direct-access crossbar-switch connector system - Google Patents

Direct-access crossbar-switch connector system Download PDF

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Publication number
US3046352A
US3046352A US810158A US81015859A US3046352A US 3046352 A US3046352 A US 3046352A US 810158 A US810158 A US 810158A US 81015859 A US81015859 A US 81015859A US 3046352 A US3046352 A US 3046352A
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United States
Prior art keywords
relay
connector
contacts
line
wire
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Expired - Lifetime
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US810158A
Inventor
Robert W Hutton
Arthur T Sigo
Charles J Adams
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TDK Micronas GmbH
International Telephone and Telegraph Corp
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Deutsche ITT Industries GmbH
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Priority to US329802A priority Critical patent/US2725428A/en
Priority to US359761A priority patent/US2909611A/en
Priority to US369342A priority patent/US2700071A/en
Priority to FR1108099D priority patent/FR1108099A/en
Priority to DEM19699A priority patent/DE971474C/en
Priority to GB26448/53A priority patent/GB731779A/en
Priority to FR53127A priority patent/FR72907E/en
Priority to FR53194A priority patent/FR72908E/en
Priority to FR53800A priority patent/FR72909E/en
Priority to BE529343D priority patent/BE529343A/xx
Priority to CH337574D priority patent/CH337574A/en
Priority to DEI8748A priority patent/DE945257C/en
Priority to CH329942D priority patent/CH329942A/en
Priority to FR54017A priority patent/FR72910E/en
Priority to US447970A priority patent/US2878320A/en
Priority to FR54100A priority patent/FR72911E/en
Priority to BE531123D priority patent/BE531123A/xx
Priority to US551192A priority patent/US2929881A/en
Priority to FR58041A priority patent/FR72922E/en
Application filed by Deutsche ITT Industries GmbH filed Critical Deutsche ITT Industries GmbH
Priority to US810158A priority patent/US3046352A/en
Application granted granted Critical
Publication of US3046352A publication Critical patent/US3046352A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/0004—Selecting arrangements using crossbar selectors in the switching stages
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H67/00—Electrically-operated selector switches
    • H01H67/22—Switches without multi-position wipers
    • H01H67/26—Co-ordinate-type selector switches not having relays at cross-points but involving mechanical movement, e.g. cross-bar switch, code-bar switch

Definitions

  • This invention relates to connector switching systems, particularly as employed in telephone switching systems, being concerned more particularly with such systems which employ direct-access crossbar switches.
  • the principal object of the invention is to provide a feasible and economical direct-access crossbar-switch connector system which makes economical use of standardized crossbar switches of relatively small capacity and employs a suitable number of them intergrouped to provide the desired connector-system capacity, one hundred lines in the illustrative example.
  • direct-access crossbar apparatus employed for providing connector access to called lines has required that horizontal multiples between verticals of a given switch be split, or eliminated, to provide the necessary lOO-line access through ten IO-line verticals, which has required expensive interswitch multipling of the 300 conductors comprising the 3-wire switchboard multiples of the respective lines of the IOO-line group.
  • the connector system has necessitated the use of a separate 10-vertical crossbar switch (or a separate 10- vertical section) for each connector trunk, thereby tending to render the system uneconomical as compared with other available types of connector-switch gear.
  • the foregoing and other disadvantages are overcome by employing, for a IOO-line connector group, five similar crossbar switches each having a full horizontal multiple and having as many verticals as may be required to accommodate the connector trunks, and each having a standardized arrangement for giving any vertical access to twenty separate 3-wire horizontal paths, with each path representing a separate line.
  • the lines of the IOU-line group thu comprise five ZO-line groups corresponding respectively to the five crossbar switches.
  • the crossbar switches each has ten 6-wire, 2-line horizontals selectable respectively by ten principal select magnets, together with twoadditional select magnets (termed upper and lower) which select either the upper three or the lower three conductors of a selected horizontal.
  • a related feature is that the upper and lower select magnets of each switch correspond respectively to the tens-group designation of the called line, and the principal select magnets of any selected switch correspond respectively to the units-digit of called lines.
  • FIG. 1 shows part of the layout of crossbar switches on four 1,000-line connector-switch frames for a 4,000-
  • each frame comprises .fifty connector switches, five for each of ten connector groups of switches. Of frame CSF1, only the final five switches CS46 to CS-Stl are shown, being those which serve as the tenth connector-switch group of the frame (CSFJ) serving the first of the four assumed LOGO-groups of subscriber lines, indexed respectively by thousands digits 2, 3, 4, and 9, for example.
  • Each of the connector switch frames, CSF-1 to CSF- i serves a separate one thousand lines.
  • the switches such as CS-46 to CS-Sti, as shown in PEG. 5, are 20 by 20 switches (twenty horizontals and twenty verticals), in which verticals 1, 2 and 15 only are shown, using the upper and lower select magnet to effectively provide the 20 horizontals.
  • each switch serves 20 lines, five connector switches serve lines and are arranged in 'a switch group such as 86-10.
  • Ten such switch groups, 86-1 to SG10, each serving 100 lines comprise a connector switch frame serving 1000 lines. Ofthe ten switch groups, only the last is shown, and in the switch group only the first, second and last switches are shown.
  • the first switch CS-46 terminates lines having tens digits 0 and 1 of the directory number; the tens digit of the numbers of the lines of switch CS-47 being 2 and 3; and the tens digits of the lines of switch CS-iifi being 8 and 9.
  • the tens digit of least value is assigned to the upper section of each horizontal. Illustrating, the tens digit 0, 2,
  • the units digit of the directory numbers of the lines assigned to horizontals correspond respectively to the hori zontal numbering as determined by the physical location of such horizontals.
  • the lines whose units digit of the directory numbers end in 1 are assigned the first horizontal, both upper and lower sections; the lines with units digits 2 are assigned to the second horizontal; and so forth CONNECTOR 1600 Referring now to FIG. 2, parts 1 and 2, the connector 1600 shown therein will be described. 1
  • Connector 1600 includes a test jack TI, 14 relays 1601 Patented July 24, 1962 The lines are terminated on the horizontals and the connectors are ter-' through 1614, condensers 1615, 1616, and 1617, rectifier 1618, resistor 1619, and magnetic impulse counters SEQ, TR, and UR.
  • Connector 1600 handles only locally terminated calls which are received over its assigned hundreds trunk 121-1, incoming from a selector switch. Connector 1600 performs the following principal circuit functions:
  • the 14 relays (1601 to 1614) of connector 1600 have principal functions assigned thereto as follows:
  • Relay 1601 (reverse battery) operates responsive to called party answer and reverses the incoming tip and ring conductors to provide any desired supervisory function;
  • Relay 1602 (line) supplies transmitter current to the calling line; operates when the connector is seized; and restores thereafter under control of the calling device or hookswitch whenever the calling line loop is opened;
  • ' Relay 1603 (back-bridge) operates over the called line when the call is answered to operate the reverse battery relay, and to supply transmitter current to the called line;
  • Relay 1604 (release) is slow-releasing by virtue of a copper sleeve under its winding; it is operated by the line relay; it remains operated during pulsing, but releases when the line relay remains restored for a substantial fraction of a second;
  • Relay 1605 (release auxiliary) is operated by the re lease relay and aids in the performance of the release relay functions
  • Relay 1606 (ring-cutoff) is operated when the called line answers to disconnect the called line from the ringing current supply;
  • Relay 1607 (ring-reverse) operates when the station digit dialed corresponds to the second station on the line to cause ringing current to be applied to the other side of the line for dividing ringing;
  • Relay 1608 (ring-trip) is slow-operating by virtue of a copper collar surrounding the armature end of its core and is operated by the DC. flow in the ringing circuit when the call is answered to open the ringing circuit and to close the talking circuit;
  • Relay 1609 (chain) is operated when the stations digit has been dialed; it seizes the chain of the local connector section for the exclusive use of this connector subject to the chain being idle;
  • Relay 1610 (busy) is operated if the called line is busy to apply busy tone signals to the calling line;
  • Relay 1611 (test) operates when the called line is idle to cut-throng the tip and ring conductors of the calling line to the tip and ring conductors of the called line;
  • Relay 1612 (series) is operated by the line relay; is slow-restoring by virtue of a copper sleeve under its winding; and it remains operated during pulsing but restores when the line relay remains restored for substantial fraction of a second;
  • Relay 1613 (series auxiliary) is operated by the series relay and aids in the performance of the functions of the series relay;
  • Relay 1614 (off-normal) operates when any one of the counters is operated and remains operated until all counters are released.
  • the three impulse counters, the combined sequence and stations counter SEQ, the tens register TR, and the units register UR of connector 1600 have principal func tions assigned thereto as follows:
  • Impulse counter SEQ (sequence and stations counter) operates at the end of each digit series of impulses to distribute such series to registers TR and UR and to record the stations digit dialed.
  • Impulse counter TR tens register registers the number of impulses in the tens digit.
  • Impulse counter UR units register registers the number of impulses in the units digit.
  • Sequence device SEQ which actuates its contact set 1 on receipt of the first operating pulse, disconnects resistor 1619 as a sleeve-guarding measure and completes an operate circuit for the off-normal relay 1614.
  • Seizure Connector 1600 is seized by the closure of the calling line loop through selector switch 1500 to the tip, ring, and sleeve conductors of hundreds trunk 1211 to the battery and ground connected windings of line relay 1602.
  • Relay 1602 operates and closes an operate circuit for release relay 1604.
  • Release relay 1604 operates and at its contacts closes an operating circuit for release auxiliary relay 1605.
  • Release auxiliary relay 1605 operates and at its contacts 1 removes the idle-indicating battery potential from the sleeve conductor and places ground potential thereon; its contacts 2 ground the ring-start wire RI-ST, starting the common ringing apparatus into operation if it is not already operating; its contacts 4 prepare an operate circuit for ring-cutofi relay 1606; its contacts 5 ground common locking wire 1636; its make contacts 6 ground common locking wire 1626; and its contacts 7 prepare the release circuit for sequence counter SEQ.
  • the seizure of the connection is accomplished during the interdigit period and immediately following the dialing of the hundreds digit of the directory number of the called line and station, the tens, units, and stations digits are dialed in succession.
  • Release relay 1604 and release auxiliary relay 1605 remain operated throughout any series of impulse-induced restorations of line relay 1602.
  • Series relay 1612 operates promptly upon the first restoration of line relay 1602, its operate circuit being from the back contacts of relay 1602, break contacts 3 of relay 1603, make contacts 7 of release auxiliary relay 1605,
  • Series auxiliary relay 1613 operates; its make contacts 3 open the initial operate circuit of the series relay 1612; and its contacts 1 prepare an operate circuit for advancing sequence counter SEQ.
  • each restoration of line relay 1602 delivers an impulse at its break contacts to pulse wire 1625 extending through break contacts 4 of sequence counter SEQ to pulse Wire 1632, as noted.
  • These ground impulses are transmitted to the operate winding of the tens register TR through break contacts 2 of the sequence counter SEQ and maintain series relay 1612 operated.
  • series relay 1612 restores after a slight delay and opens the operate circuit of relay 1612 which restores sequentially a short time later.
  • the ground appearing on wire 1636 is extended through break contacts 1 of relay 1613 to deliver a stepping impulse to sequence counter SEQ.
  • This stepping impulse which is delivered to device SEQ at the end of the receipt and registration of the tens digit
  • make contacts 1A close an operate circuit for off-normal relay 1614; break contacts 1A disconnect idle-indicating battery from wire 1633 to prevent the reapplication of idle-indicating potential to the incoming sleeve conductor of the connector before the device SEQ is cleared out; break contacts 1B disconnect the incoming impulse wire 1632 from the first tens register TR; and make contacts 13 transfer such pulsing wire to the operate winding of units register UR.
  • a series of circuit interruption impulses are transmitted over pulsing wire 1625 and are extended through break contacts land make contacts 18 of counter SEQ to the battery-connected winding of units register UR.
  • these circuit-interruption impulses are transmitted to series relay 1612 which operates as noted and operates series auxiliary relay 1613.
  • the contact sets 1 to 10 of register UR are actuated successively, responsive respectively to the impulses constituting the units digit.
  • series relay 1612 restores after a slight delay andthereafter restores series auxiliary relay 1613, as noted.
  • a second stepping impulse is thereupon delivered to the winding of sequence device SEQ from the ground on conductor 1636 causing it to shift its contact set 2 to its alternate position which opens the operate circuit of units register UR and transfers the pulsing wire to wire 1638 extending to the winding of counter SEQ.
  • ground impulses are transmitted over wires 1625 and 1638 through contacts 2, 3, and 4 of device SEQ to the operate Winding of sequence device SEQ:
  • series relay 1612 operates followed thereafter by the operation of relay 1613. The make contacts on requence device SEQ closed.
  • the stations digit comprises one or two impulses depending on whether the called party is on the tip or ring side of the called line. Therefore, responsive to the dialing of the stations digit, sequence device SEQ operates its contacts 3 or 4 depending on whether stations digit 1 or digit 2 were dialed. Assuming that the digit 2 is dialed, the sequence device actuated its contact sets 3 and 4 responsive to the two impulses of the dialed digit.
  • sequence device SEQ actuates its contact sets 5 which shift to their alternate position, thereby connecting wire 1628 to Wire 1637.
  • series auxiliary relay 1613 restores and the ground on wire 1636 is extended to wire 1637 which is connected to the battery-connected winding of the ring-reverse relay 1607 through SEQ contacts 5, over wire 1628 and make contacts 3.
  • ground on wire 1637 is extended through make contacts 4 of device-SEQ to Wire 1621 extending to one side of the chain relay 1609 through break contacts on the busy relay and the test relay.
  • Ring-reverse relay 1607 operates and locks through its make contacts 3 to the grounded conductor 1636, and at its make contacts 1 and 2 transfer the generatorground wire GEN-6RD from the ring conductor of the called line to the tip conductor in preparation for signalling the called station on the tip conductor of the line.
  • Contacts 3 and 1 of chain relay 1609 prevent any interference by other connectors associated with controller 1766 and renders the controller individual to the calling tens digit wires and the units digit Wires extending to V the connector controller and connector switches; and make contacts 7 connect the secondary-ofimormal wire SON to hold magnet operate Wire HM-OP.
  • the tens register TR connects grounded -wire 1630 to tens wire T-0 and the units register UR connects ground wire 1631 to units wire U-ll.
  • the tens digit is not assigned to a PBX group, no PBX hunting takes place.
  • the ground appearing on the selected tens and units digit wires is extended to the connector controller and connector switch thereby causing the tip, ring, and sleeve conductors of the calling connector to be extended to .the tip, ring, and sleeve conductors of the called line by operation of the connector controller.
  • the sleeve conductor of the called line is extended to one side of the upper winding of test relay 1611, the other side of such Winding being connected to ground potential on wire 1626 through break contacts 3 of busy relay 1610 and rectifier 1618.
  • Rectifier 1613 prevents the ground on wire 1626 from being projected forward on the sleeve conductor so that the cutoff relay associated with the calling line will not be operated prematurely.
  • Relay 1618 operates and locks operated through its lower winding and make-first contacts 7; its make contacts 4 ground the sleeve conductor S to operate the cutoff relay of the called line to prevent answer by the called line from causing line finding action to take place; its contacts 2 and 3 connect the battery and ground connected windings of the backbridge relay 1603 to the tip and ring conductors of the called line; its make contacts 1 apply ring-tone from con ductor RT through tone-coupling condenser 1717 to the tip conductor of the calling line thereby signalling that ringing has started; its break contacts 5 open the operate circuit of the busy relay from the grounded busy conductor BU; its contacts 6 connect generator battery lead GEN-BATT to the ring conductor of the called line in series with the winding of ring-trip relay 1608; and at its contacts 8 free the seized chain thereby
  • the Called Line Tests Busy Assuming that the called line is busy, the sleeve conductor of the called line has ground potential thereon from the connector in use and this ground appears on the sleeve conductor short-circuiting the upper winding of test relay 1611, preventing its operation.
  • test relay 1611 Responsive to the failure of test relay 1611 to operate, after a slight delay, the ground potential on the busy lead BU, originating at the cit-normal contacts of the operated hold magnet, is extended through break contacts 5 of the unoperated test relay to the battery-connected winding of busy relay 1610.
  • Busy relay 1610 operates, and at its contacts 1 applies busy tone to the calling line through the tonecoupling condenser 1617. Its make contacts 2 extend the ground potential from make contacts 3 of release auxiliary relay 1605, through make contacts 2 of relay 1610 locking it operated. Break contacts 3 of the busy relay 1610 opens the operate circuit of the upper winding of test relay 1611 and at break contacts 4 free the chain, thereby releasing the common equipment.
  • Called Line Answer Ring-trip relay 1608, whose winding is included in the ringing circuit does not operate before the call is answered for each ringer (not shown) on the called line has the usual condenser in series therewith to block direct-current flow and because the shading collar surrounding the armature end of the core, keeps it from responding to the alternating ringing current.
  • the applied frequency of ringing current is in series with (superimposed upon) the exchange battery.
  • Ring-cutoff relay 1606 operates and at its make-break contacts 1 disconnects ringing tone from the calling line; its make contacts 2 and 3 transfer the tip and ring condoctors of the called line from the ringing current and extends the talking bridge across the ground and battery connected windings of back-bridge relay 1603, thereby supplying transmitter current to the called line; its break contacts 4 restore ring-reverse relay 1607 and its make contacts 5 lock ring-cutoff relay 1606 operated to the ground on locking conductor 1626. Ring-trip relay 1603 restores, its operate circuit being opened by contacts 2 and 3 of restored ring-cutoff relay 1606.
  • the transmitter current flow through the windings of relay 1603 cause it to operate and at its contacts 1 to remove the ground from the ring-start wire RI-ST; its contacts 2 close an operate circuit for reverse-battery relay 1601; and at its break contacts 3 opens the pulsing wire 1625.
  • the relay 1601 operates and at its contacts 4 maintains an additional ground on locking conductor 1626, rendering the connector last-party release. Its contacts 1 and 2 reverse the tip and ring conductors of the calling line performing any required supervisory function, and at its contacts 3 opens the idle indicating battery supply wire.
  • Clearout 7 bridge relay 1603 restores, and restores reverse-battery relay 1601. With the restoration of relay 1601, ground is removed from locking wire 1626 and all operated relays restore with the exception of oifnormal relay 1614 which is maintained operated by contacts 1 of the counters, the counters being held operated by residual magnetism.
  • Ground potential from break contacts of the line relay 1602 is extended to wire 1627 through break contacts 3 of relays 1603 and 1605. This ground is further extended through the back contacts 2 of relay 16111, break contacts 1 of ring-reverse relay 1607, the winding of ring-trip relay 1608, break contacts 2 of chainrelay 1609', break contacts 6 of test relay 1611 to wire 1635 from whence it is extended through make contacts 1 of off-normal relay 1614 to battery through the restoring windings of the counters SEQ, TR and UR in series.
  • the magnetic flux generated by the current flow through the restoring windings is in opposition to the residual magnetism thereby each counter restores.
  • the operate circuit of the off-normal relay 1614 is opened, restoring it.
  • the knock-down or restoration circuit of the counters is opened at contacts 1 and resistor 1619 is again connected to wire 1633.
  • PBX Service As will be described in detail hereinafter, certain lines of this exchange may be arranged to provide PBX service, these lines having certain tens digits assigned thereto.
  • the tens digit assigned PBX service is followed by the dialing of the units digit 1, else the call will be extended to the called line whether a PBX line or not. This operation will be described in connection with the connector controller.
  • One connector controller is provided to serve the one hundred lines associated with five connector switches of any switch group.
  • the connector controller functions to connect associated calling connectors with called lines on a one-at-a-time basis.
  • the illustrated connector controller is assumed to be associated with switch group SG- of connector frame CSF-l, FIG. 1, of which the first switch is shown in FIG. 5.
  • connector controller 1700 The purpose of connector controller 1700 is to control the crossbar connector switch 1900' in connecting the calling connectors, such as connector 1600, to called lines.
  • Connector controller 1700 comprises PBX relays 1750 and connector switch connector relays 1850 suitably interconnected with each other and associated with the five connector switches of a switch group, one such switch being shown in FIG. 5, to perform the necessary switching operation in extending calls to called subscriber and PBX lines.
  • connector controller 1700 General Operation On calls starting from the normal cleared out condition, the general operation of connector controller 1700 is as follows: 1
  • connector switch CSS-46 ofswitch group SG-10 of connector switch frame CSF-l is connector switch CSS-46 ofswitch group SG-10 of connector switch frame CSF-l, as noted in FIG. 1, the lines having the tens and units digits ending in 01 to 09 and 10 to 19 are served by such switch.
  • Ground appearing on the units lock off-normal lead UL-ON causes the connect relays associated with switch 1900 to operate and close the select magnet and hold magnet leads through to the magnets of the connector switch.
  • Ground on the units digit leads from the units register UR is transmitted to the winding of the select magnet associated with the called line.
  • the select magnet associated with the double horizontal serving two lines operates and together with the operation of either the upper or lower select magnets, selects the one horizontal that serves the called line.
  • Ground potential is placed on the secondary-ofi-normal lead SON and is extended to the connector chain relay contacts and is connected to the hold magnet operate wire HM-OP.
  • the lhold magnet associated with the vertical terminating the calling connector operates and closes the tip
  • the off-normal contacts on the hold magnet lock the hold magnet operated to the noted ground on the lock lead L and place ground on the busy lead BU extending to the connector, as previously pointed out.
  • the chain relay is released thereby removing the ground from winding of'the operated auxiliary select magnet SMU or SML and from the selected one of the principal select magnet leads SM-1 to SM-10. All select magnets are deenergized, but the cross points between the verticals and horizontals and the upper or lower contact group selected by select magnets SMU or SML are held closed by the continued operation of the hold magnet.
  • the operation will be similar excepting that upon operation of the busy relay and consequent restoration of chain relay, the locking circuit of the operated hold magnet will be opened, thereby returning the switch to normal condition.
  • PBX Service Certain lines served by a connection switch are adapted for PBX service by extending the sleeve conductor of a line assigned PBX service to PBX group relays from whence they are used in determining the busy or idle condition of such lines. Two such sleeve extensions are shown in cable 1735.
  • the relays of connector controller 1700 comprise the i following functions groups: p
  • the lower select magnet and the lines having the tens digit I .0 are associated with the horizontals associated with the upper select magnet.
  • connector switch CSS- 2 is assigned the tens digits 2 and 3; the third switch is assigned the tens digits 4 and 5; and so torth.
  • the tens wires T1 to T are associated with the batteryconnected windings of lower select magnet SML and upper select magnet SMU, respectively.
  • each of the relays 1801 to 1803 operate and close their make contacts 1 to 10.
  • ground appears on the units digit wire U-l and is extended over an associated conductor SMC-l in cable group 1737 to contacts 1 on the connect relay 1803.
  • ground on digit wire U-1 is extended through make contacts 1 of relay 1803 to the battery-connected winding of principal select magnet SM-l, such magnet being associated with the double horizontal terminating the called line.
  • the lower horizontal of double horizontal 1-1-1 is selected, such horizontal being associated with the called line.
  • the off-normal contacts of the operated principal select magnet ground the secondary-otf-normal conductor SON which, as noted, is connected to the hold magnet operate wire HM-OP through contacts 7 of the calling connector from whence it is extended through make contacts 1 of the operated switch connect relay 1801 to the hold magnet wire HM-1 extending to the battery-connected winding of hold magnet HM-1901 over conductors in cable group 1836.
  • the contacts 1 to 10 of relay 1801 and contacts 1 to 10 on relay 1802 serve to connect the hold magnet operate wires of each of the calling connectors associated with any switch group to the hold magnet associated with the vertical terminating such connector, in this disclosure connectors being served by the connector switches of a switch group.
  • the called line associated with select magnet SM-l and upper select magnet SMU is connected through the cross points of horizontal H1 and vertical V1 to the tip, ring, and sleeve conductors of the calling connector and the testing of the called line is performed in the manner previously described.
  • the chain relay Upon finding such line idle, the chain relay is restored thereby disconnecting the secondary-ofi-normal wire SON from the hold magnet wire HM-OP and removing the ground from the tens and units digit wires T-0 and U-1, thereby permitting the auxiliary select magnet SMU and principal select magnet SM-l to restore.
  • the indicated cross points of horizontal H1 and vertical V1, together with the contacts associated with the upper select magnet are maintained closed as long as hold magnet HM-1901 is operated.
  • the initial operate circuit of hold magnet HM-1901 is opened but it does not restore as ground from lock conductor L of calling connector 1600 maintains it operated.
  • PBX Service It has been chosen to provide certain ones of the lines whose directory number tens digit is 1, 2, 3, or 4, for PBX service.
  • the lines associated with the horizontals H1 and H2 and associated with the lower select magnet are arranged in a PBX group by connecting an extension of the sleeve conductor to the PBX grouping relays of MG. 3 over conductors in cable group 1735. Accordingly, with the dialing of the tens digit 1, thereby operating the auxiliary select magnet SML and the dialing of the units digit l, thereby operating select magnet SM-l, the PBX relays 1750 are operated to extend the call to an idle line in the PBX group.
  • the lower select magnet SML operates as hereinbefore described, responsive to the grounding of the associated digit wire and at its off-normal contacts, operates it associated connector switch connect relays to connect the select magnet and hold magnet wires to the coiresponding magnets of switch 1900.
  • Relay 1701 operates from the ground appearing on the tens extension wire T 13-1 and at its contacts 12 closes an operate circuit for units relay 1705 from the ground appearing on the units wire U-1; at its contacts 1 to 10, connects the sleeve wires of all lines serving as PBX lines (in this disclosure S1 and S2 extending to the PBX grouping relays over conductors in cable 1735) to the make contacts 1 to 10 of units auxiliary relay 1706; and at its contacts 11 connects battery through resistor 1731 to locking conductor 1722 in preparation for locking any PBX test relays that operated.
  • PBX lines in this disclosure S1 and S2 extending to the PBX grouping relays over conductors in cable 1735
  • each such relay connecting the sleeves of the lines in their respective PBX groups to the units auxiliary relay for test to determine their busy or idle condition.
  • Units relay 1705 operates from the ground on units digit wire U-l and at its make contacts 1 prepares an operate circuit for units auxiliary relay 1706; its make contacts 2 prepare an operate circuit for slow-operating busy relay 1708; and its break contacts 3 open the select magnet control wire SMC-l thereby delaying the operation of all select magnets until an idle line in the called PBX group is determined.
  • Units auxiliary relay 1706 operates and at its make contaste 1 to 10 connects the sleeve wires of the lines of switch 1900 serving as PBX lines to the ground-connected winding of the PBX test relays.
  • switch 1900 has two lines serving as PBX lines and assuming the first PBX line is busy, the ground potential on the sleeve conductor of the busy lines and the battery potential from the battery-connected winding of the cutoff relay of the associated line circuit of the second line are extended through the closed contacts on the PBX grouping relays and the contacts of units auxiliary relay 1706 to the ground-connected winding of the PBX test relays 1709 to 1718.
  • Relay 1709 is short-circuited by the grounded sleeve conductor and fails to operate but relay 1710 operates in series with the battery-connected winding of the cutoff relay. Relay 1710, at its contacts 1, locks operated to the locking battery potential on locking conductor 1722;
  • Cutoff relay 1707 operates and at its break contacts 1 disconnects the sleeve extensions of the calling line from the PBX test relays; at its make contacts 2 disconmeets the operate circuit of the busy relay 1708, this operation being performed before the operate time of the busy relay 1708 has elapsed and extends ground potential from make contacts 2 of units relay 1705 through break contacts 3 of relay 1709 and make contacts 3 of relay 1710 to the select magnet control wire SMC-Z extending to the select magnet associated with the second line in the calledPBX group.
  • Select magnet SM-Z operates and at its cit-normal contacts grounds the secondary-ofi-normal wire SON,
  • the calling line is connected to the called line, such called line being the second line of the PBX group, and the connector controller is cleared out as previously described.
  • cutoff relay 1707 fails to operate and ground from make contacts 2 of units relay 1705 is extended to: the battery-connected winding of slow-operate busy relay 1708 for a substantial fraction of a second and causes this relay to operate.
  • ground potential is placed on the PBX-BUSY lead extending to the calling connector.
  • the busy relay of the calling connector operates and supplies busy tone to the calling line.
  • units relay 1705 restores and the operated one of the PBX grouping relays restore, thereby completely clearing out the PBX relays 1-750.
  • ground is removed from the units lock off-normal wire and the operated connector switch connect relays are restored.
  • the connector controllear 1700 is now restored to common use in preparation for calls from other connectors.
  • control means common to said trunks, means controlled over any trunk for operating said control means in accordance with the tens and units digits of any desired called line, said control means including means for selecting the switch terminating the called line according to the called tens digit and for operating the one of the auxiliary select magnets thereof which correspond to such tens digit, the control means further including means for operating the principal select magnet which corresponds to the called units digits and means for operating the hold magnet or" the selected switch which corresponds to the last said trunk to complete a connection to the called line according to which auxiliary select magnet and which principal select magnet have been operated.
  • control means including means for directly operating the auxiliary select magnet which corresponds to the called tens digit, twenties relays associated respectively to said crossbar switches, means responsive to the said operation of either auxiliary select magnet of a switch for operating the associated twenties relay, and means controlled by the operated twenties relay for rendering the principal select magnets of the associated switch responsive according tothe units digit of the called line.
  • said trunks having respective individualizing relays and means for operating any one of them to temporarily individualize the associated trunk with the com mon equipment, the said means for operating :any hold magnet including contact means of an operated individualizing relay in series with contact means of an operated twenties relay, and a by-passing maintaining circuit for any operated hold magnet.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Exchange Systems With Centralized Control (AREA)
  • Structure Of Telephone Exchanges (AREA)
  • Keying Circuit Devices (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)
  • Breakers (AREA)
  • Catalysts (AREA)
  • Telephonic Communication Services (AREA)

Description

July 24, 1962 R. w. HUTTON ETAL 3,04
DIRECT-ACCESS CROSSBAR-SWITCH CONNECTOR SYSTEM Original Filed June 5, 1953 6 Sheets-Sheet 2 FROM SELECTOR SWITCH 50 10 25 5 J. PNZE N OE mw w (um. ww 82 32 x3 mw E mmim wz: Him ww 5m I11? n .m II 22 i v a 9m. fl i C3 96 hm. Zww zw? Lw F5558 002 138228 0252i Oh July 24, 1962 R. w. HUTTON ETAL DIRECT-ACCESS CROSSBARSWITCH CONNECTOR SYSTEM Original Filed June 5, 1953 TO CONNECTOR SWITCH r'-' UNITS REGISTER l l l I FIG. 2 PART 2 TENS REGISTER ||zs4seveexol SEQ. DEVICE 6 Sheets-Sheet 3 TO CONNECTOR 234 SW'TCHES l234567890 TO CONNECTOR CONTROLLER BX BUSY HM-OPJ July 24, 1962 R. w. HUTTON ETAL 3,046,352
DIRECT-ACCESS CROSSBAR-SWITCH CONNECTOR SYSTEM Original Filed June 5, 1953 6 Sheets-Sheet 4 PBX TEST RLYS.
UNITS UNITS AUX. 0.0. BUSY T0 couu. swfa P8X RELAYS TO/FROM CONNECTOR I600 T0 comi. sw.*2
PBX GROUPING RLYS.
July 24, 1962 R. w. HUTTON ETAL 3,046,352
DIRECT-ACCESS CROSSBAR-SWITCH CONNECTOR SYSTEM 6 Sheets-Sheet 6 Original Filed June 5, 1953 ONmTZI ON E llll mdE
TO LINES This invention relates to connector switching systems, particularly as employed in telephone switching systems, being concerned more particularly with such systems which employ direct-access crossbar switches. The principal object of the invention is to provide a feasible and economical direct-access crossbar-switch connector system which makes economical use of standardized crossbar switches of relatively small capacity and employs a suitable number of them intergrouped to provide the desired connector-system capacity, one hundred lines in the illustrative example.
This application is a division of our application Serial No. 359,761, filed lune 5, 1953, now Patent No. 2,999,611.
Heretofore, for the most part, direct-access crossbar apparatus employed for providing connector access to called lines has required that horizontal multiples between verticals of a given switch be split, or eliminated, to provide the necessary lOO-line access through ten IO-line verticals, which has required expensive interswitch multipling of the 300 conductors comprising the 3-wire switchboard multiples of the respective lines of the IOO-line group. Moreover, the connector system has necessitated the use of a separate 10-vertical crossbar switch (or a separate 10- vertical section) for each connector trunk, thereby tending to render the system uneconomical as compared with other available types of connector-switch gear.
According to the invention, the foregoing and other disadvantages are overcome by employing, for a IOO-line connector group, five similar crossbar switches each having a full horizontal multiple and having as many verticals as may be required to accommodate the connector trunks, and each having a standardized arrangement for giving any vertical access to twenty separate 3-wire horizontal paths, with each path representing a separate line. The lines of the IOU-line group thu comprise five ZO-line groups corresponding respectively to the five crossbar switches.
In the illustrative example, the crossbar switches each has ten 6-wire, 2-line horizontals selectable respectively by ten principal select magnets, together with twoadditional select magnets (termed upper and lower) which select either the upper three or the lower three conductors of a selected horizontal. A related feature is that the upper and lower select magnets of each switch correspond respectively to the tens-group designation of the called line, and the principal select magnets of any selected switch correspond respectively to the units-digit of called lines.
United States Patent A further feature is that, whereas each connector trunk "ice .1 to of an embodiment of the invention taken in conjunction with the accompanying drawings, comprising FIGS. 1 to 5, wherein:
FIG. 1 shows part of the layout of crossbar switches on four 1,000-line connector-switch frames for a 4,000-
1 line system;
CONNECTOR SWITCH FRAMES Referring now to FIG. 1, each frame comprises .fifty connector switches, five for each of ten connector groups of switches. Of frame CSF1, only the final five switches CS46 to CS-Stl are shown, being those which serve as the tenth connector-switch group of the frame (CSFJ) serving the first of the four assumed LOGO-groups of subscriber lines, indexed respectively by thousands digits 2, 3, 4, and 9, for example. Each of the connector switch frames, CSF-1 to CSF- i, serves a separate one thousand lines. The switches such as CS-46 to CS-Sti, as shown in PEG. 5, are 20 by 20 switches (twenty horizontals and twenty verticals), in which verticals 1, 2 and 15 only are shown, using the upper and lower select magnet to effectively provide the 20 horizontals.
minated on the verticals. Since each switch serves 20 lines, five connector switches serve lines and are arranged in 'a switch group such as 86-10. Ten such switch groups, 86-1 to SG10, each serving 100 lines comprise a connector switch frame serving 1000 lines. Ofthe ten switch groups, only the last is shown, and in the switch group only the first, second and last switches are shown.
It has been chosen to provide the one hundred lines in any switch group with 15 connectors. These connectors are terminated on the verticals of the connector switches which are connected together by conductors in cable groups, such as 1fi-l8tl-1 to cable 10-18045 for switch group SG-1.0. The 1000' lines in any connector switch frame are therefore served by connectors.
Referring now to the five connector switches CS-46 to CS-St), it will be observed that the first switch CS-46 terminates lines having tens digits 0 and 1 of the directory number; the tens digit of the numbers of the lines of switch CS-47 being 2 and 3; and the tens digits of the lines of switch CS-iifi being 8 and 9. On each of the switches, the tens digit of least value is assigned to the upper section of each horizontal. Illustrating, the tens digit 0, 2,
4, 6, and 8are associated with the upper section while tens digits 1, 3, 5, 7, and 9 are associated with the lower section of the horizontals, this association being controlled by the tens digit wire assignment to the auxiliary select magnets.
The units digit of the directory numbers of the lines assigned to horizontals correspond respectively to the hori zontal numbering as determined by the physical location of such horizontals. The lines whose units digit of the directory numbers end in 1 are assigned the first horizontal, both upper and lower sections; the lines with units digits 2 are assigned to the second horizontal; and so forth CONNECTOR 1600 Referring now to FIG. 2, parts 1 and 2, the connector 1600 shown therein will be described. 1
Connector 1600 includes a test jack TI, 14 relays 1601 Patented July 24, 1962 The lines are terminated on the horizontals and the connectors are ter-' through 1614, condensers 1615, 1616, and 1617, rectifier 1618, resistor 1619, and magnetic impulse counters SEQ, TR, and UR.
Connector 1600 handles only locally terminated calls which are received over its assigned hundreds trunk 121-1, incoming from a selector switch. Connector 1600 performs the following principal circuit functions:
(1) Normally, it supplies idle-indicating battery potential to the sleeve conductor of the attached hundreds trunk;
(2) Upon seizure it removes the idle-indicating battery potential and substitutes a holding potential therefor;
(3) It receives and stores three digits, two digits for transfer to the connector controller to control the extension of a connection to a desired line;
(4) It temporarily seizes the chain circuit of its connector section subject to such chain being idle and thereafter guards the seized chain against seizure by any other connector in the same section;
(5) It transfers the two digits of stored digit information to the connector controller while it has the chain seized;
(6) Upon a signal that the called line is busy, it applies busy tone to the calling line and frees the seized chain;
(7) When the called line is idle, it applies ringing tone to the calling line; signals the called line; and frees the seized chain;
(8) When the call is answered, it trips the ringing circuit; completes the talking connection; and reverses the current flow over the tip and ring conductors of the attached hundreds trunk;
(9) It supplies transmitter current to both lines;
(10) Upon disconnect by the calling and called line, it clears out and releases the entire connection by removing holding ground from the incoming sleeve and from the sleeve of the forward connection; and
(11) It provides PBX special services.
The 14 relays (1601 to 1614) of connector 1600 have principal functions assigned thereto as follows:
Relay 1601 (reverse battery) operates responsive to called party answer and reverses the incoming tip and ring conductors to provide any desired supervisory function;
Relay 1602 (line) supplies transmitter current to the calling line; operates when the connector is seized; and restores thereafter under control of the calling device or hookswitch whenever the calling line loop is opened;
' Relay 1603 (back-bridge) operates over the called line when the call is answered to operate the reverse battery relay, and to supply transmitter current to the called line;
Relay 1604 (release) is slow-releasing by virtue of a copper sleeve under its winding; it is operated by the line relay; it remains operated during pulsing, but releases when the line relay remains restored for a substantial fraction of a second;
Relay 1605 (release auxiliary) is operated by the re lease relay and aids in the performance of the release relay functions;
Relay 1606 (ring-cutoff) is operated when the called line answers to disconnect the called line from the ringing current supply;
Relay 1607 (ring-reverse) operates when the station digit dialed corresponds to the second station on the line to cause ringing current to be applied to the other side of the line for dividing ringing;
Relay 1608 (ring-trip) is slow-operating by virtue of a copper collar surrounding the armature end of its core and is operated by the DC. flow in the ringing circuit when the call is answered to open the ringing circuit and to close the talking circuit;
Relay 1609 (chain) is operated when the stations digit has been dialed; it seizes the chain of the local connector section for the exclusive use of this connector subject to the chain being idle;
Relay 1610 (busy) is operated if the called line is busy to apply busy tone signals to the calling line;
Relay 1611 (test) operates when the called line is idle to cut-throng the tip and ring conductors of the calling line to the tip and ring conductors of the called line;
Relay 1612 (series) is operated by the line relay; is slow-restoring by virtue of a copper sleeve under its winding; and it remains operated during pulsing but restores when the line relay remains restored for substantial fraction of a second;
Relay 1613 (series auxiliary) is operated by the series relay and aids in the performance of the functions of the series relay; and
Relay 1614 (off-normal) operates when any one of the counters is operated and remains operated until all counters are released.
The three impulse counters, the combined sequence and stations counter SEQ, the tens register TR, and the units register UR of connector 1600 have principal func tions assigned thereto as follows:
Impulse counter SEQ (sequence and stations counter) operates at the end of each digit series of impulses to distribute such series to registers TR and UR and to record the stations digit dialed.
Impulse counter TR (tens register) registers the number of impulses in the tens digit.
Impulse counter UR (units register) registers the number of impulses in the units digit.
Sequence device SEQ, which actuates its contact set 1 on receipt of the first operating pulse, disconnects resistor 1619 as a sleeve-guarding measure and completes an operate circuit for the off-normal relay 1614.
DETAILED CONNECTOR OPERATION A detailed operation of connector 1600 will now be given.
Seizure Connector 1600 is seized by the closure of the calling line loop through selector switch 1500 to the tip, ring, and sleeve conductors of hundreds trunk 1211 to the battery and ground connected windings of line relay 1602. Relay 1602 operates and closes an operate circuit for release relay 1604.
Release relay 1604 operates and at its contacts closes an operating circuit for release auxiliary relay 1605.
Release auxiliary relay 1605 operates and at its contacts 1 removes the idle-indicating battery potential from the sleeve conductor and places ground potential thereon; its contacts 2 ground the ring-start wire RI-ST, starting the common ringing apparatus into operation if it is not already operating; its contacts 4 prepare an operate circuit for ring-cutofi relay 1606; its contacts 5 ground common locking wire 1636; its make contacts 6 ground common locking wire 1626; and its contacts 7 prepare the release circuit for sequence counter SEQ.
As hereinbefore pointed out, the seizure of the connection is accomplished during the interdigit period and immediately following the dialing of the hundreds digit of the directory number of the called line and station, the tens, units, and stations digits are dialed in succession.
Tens Digit Registration Each time the calling device (not shown) is operated to transmit a series of circuit interruption impulses constituting the tens, units, and stations digits, line relay 1602 is restored momentarily for each such interruption impulse in a series, comprising from one to ten impulses, depending upon the digit dialed.
Release relay 1604 and release auxiliary relay 1605 remain operated throughout any series of impulse-induced restorations of line relay 1602.
Series relay 1612 operates promptly upon the first restoration of line relay 1602, its operate circuit being from the back contacts of relay 1602, break contacts 3 of relay 1603, make contacts 7 of release auxiliary relay 1605,
. wire 1625, break contacts 4 of sequence counter SEQ,
wire 1632, and break contacts 3 of series auxiliary relay 1613 to the battery-connected winding of series relay 1612. Upon operating, series relay 1612 locks operated independent of contacts 3 of series auxiliary relay 1613. At its make contacts 1, relay 1612 completes an operate circuit for auxiliary relay .1603 from the ground on grounded wire 1636.
Series auxiliary relay 1613 operates; its make contacts 3 open the initial operate circuit of the series relay 1612; and its contacts 1 prepare an operate circuit for advancing sequence counter SEQ.
With release auxiliary relay 1605 maintained continuously operated, each restoration of line relay 1602 delivers an impulse at its break contacts to pulse wire 1625 extending through break contacts 4 of sequence counter SEQ to pulse Wire 1632, as noted. These ground impulses are transmitted to the operate winding of the tens register TR through break contacts 2 of the sequence counter SEQ and maintain series relay 1612 operated.
When line relay 1602 comes to rest, operated, at the end of any digit series of impulses, series relay 1612 restores after a slight delay and opens the operate circuit of relay 1612 which restores sequentially a short time later. At such time when series relay 1612 is restored and series auxiliary relay 1613 is yet operated, the ground appearing on wire 1636 is extended through break contacts 1 of relay 1613 to deliver a stepping impulse to sequence counter SEQ.
This stepping impulse which is delivered to device SEQ at the end of the receipt and registration of the tens digit,
causes both its contact sets 1A and 13 to shift to their alternate positions. Make contacts 1A close an operate circuit for off-normal relay 1614; break contacts 1A disconnect idle-indicating battery from wire 1633 to prevent the reapplication of idle-indicating potential to the incoming sleeve conductor of the connector before the device SEQ is cleared out; break contacts 1B disconnect the incoming impulse wire 1632 from the first tens register TR; and make contacts 13 transfer such pulsing wire to the operate winding of units register UR.
Units Digit Registration Responsive to the dialing of the units digit of the called directory number, a series of circuit interruption impulses are transmitted over pulsing wire 1625 and are extended through break contacts land make contacts 18 of counter SEQ to the battery-connected winding of units register UR. At the same time, these circuit-interruption impulses are transmitted to series relay 1612 which operates as noted and operates series auxiliary relay 1613. The contact sets 1 to 10 of register UR are actuated successively, responsive respectively to the impulses constituting the units digit.
When line relay 161 comes to rest, operated, at the end of the dialing of the units digit, series relay 1612 restores after a slight delay andthereafter restores series auxiliary relay 1613, as noted. A second stepping impulse is thereupon delivered to the winding of sequence device SEQ from the ground on conductor 1636 causing it to shift its contact set 2 to its alternate position which opens the operate circuit of units register UR and transfers the pulsing wire to wire 1638 extending to the winding of counter SEQ.
Stations Digit Registration Responsive to the restoration and reoperation of the line relay according to the impulses of the stations digit, ground impulses are transmitted over wires 1625 and 1638 through contacts 2, 3, and 4 of device SEQ to the operate Winding of sequence device SEQ: At the same time, series relay 1612 operates followed thereafter by the operation of relay 1613. The make contacts on requence device SEQ closed.
The stations digit comprises one or two impulses depending on whether the called party is on the tip or ring side of the called line. Therefore, responsive to the dialing of the stations digit, sequence device SEQ operates its contacts 3 or 4 depending on whether stations digit 1 or digit 2 were dialed. Assuming that the digit 2 is dialed, the sequence device actuated its contact sets 3 and 4 responsive to the two impulses of the dialed digit.
Responsive to the third stepping impulse delivered over wire 1636, sequence device SEQ actuates its contact sets 5 which shift to their alternate position, thereby connecting wire 1628 to Wire 1637.
Shortly after the third stepping impulse from 1636 is delivered to the operate winding of sequence device SEQ, series auxiliary relay 1613 restores and the ground on wire 1636 is extended to wire 1637 which is connected to the battery-connected winding of the ring-reverse relay 1607 through SEQ contacts 5, over wire 1628 and make contacts 3. At thev sametime, ground on wire 1637 is extended through make contacts 4 of device-SEQ to Wire 1621 extending to one side of the chain relay 1609 through break contacts on the busy relay and the test relay.
Ring-reverse relay 1607 operates and locks through its make contacts 3 to the grounded conductor 1636, and at its make contacts 1 and 2 transfer the generatorground wire GEN-6RD from the ring conductor of the called line to the tip conductor in preparation for signalling the called station on the tip conductor of the line.
As described in the parent application with reference to selectors 1100 and 1206', battery from the chain-end wire (in the connector controller, resistor 1749) completes an operate circuit for chain relay 1669 providing the selector controller is idle and no other connectors have their chain relays operated. I
With line relay 1602, release relay 1604, release auxiliary relay 1605, and ring-reverse relay 1607 operated, sequence device SEQ in position 5, and the tens and units registers TR and UR set according to their respective registered digits, an operate circuit is closed for the chain relay, which operates provided the chain is idle, as noted.
Contacts 3 and 1 of chain relay 1609 prevent any interference by other connectors associated with controller 1766 and renders the controller individual to the calling tens digit wires and the units digit Wires extending to V the connector controller and connector switches; and make contacts 7 connect the secondary-ofimormal wire SON to hold magnet operate Wire HM-OP.
Testing the Called Line Assuming that the called line was reached by dialing directory nunrber 2101-2 (tens digit 0, units digit 1, and stations digit 2), the tens register TR connects grounded -wire 1630 to tens wire T-0 and the units register UR connects ground wire 1631 to units wire U-ll. As will be described hereinafter, since the tens digit is not assigned to a PBX group, no PBX hunting takes place. The ground appearing on the selected tens and units digit wires is extended to the connector controller and connector switch thereby causing the tip, ring, and sleeve conductors of the calling connector to be extended to .the tip, ring, and sleeve conductors of the called line by operation of the connector controller.
As will be described hereinafter, when the hold magnet associated with the vertical terminating the calling connector operates, it locks operated through oil-normal contacts to the grounded locking conductor L and at other off-normal contacts ground busy wire BU.
At the time that such hold magnet operates and closes its off-normal contacts, the sleeve conductor of the called line is extended to one side of the upper winding of test relay 1611, the other side of such Winding being connected to ground potential on wire 1626 through break contacts 3 of busy relay 1610 and rectifier 1618. Rectifier 1613 prevents the ground on wire 1626 from being projected forward on the sleeve conductor so that the cutoff relay associated with the calling line will not be operated prematurely.
Assuming the called line to be idle, the battery potential from the battery-connected winding of the cutoff relay of called line, causes current flow through the upper winding of test relay 1618. Relay 1618 operates and locks operated through its lower winding and make-first contacts 7; its make contacts 4 ground the sleeve conductor S to operate the cutoff relay of the called line to prevent answer by the called line from causing line finding action to take place; its contacts 2 and 3 connect the battery and ground connected windings of the backbridge relay 1603 to the tip and ring conductors of the called line; its make contacts 1 apply ring-tone from con ductor RT through tone-coupling condenser 1717 to the tip conductor of the calling line thereby signalling that ringing has started; its break contacts 5 open the operate circuit of the busy relay from the grounded busy conductor BU; its contacts 6 connect generator battery lead GEN-BATT to the ring conductor of the called line in series with the winding of ring-trip relay 1608; and at its contacts 8 free the seized chain thereby restoring the chain relay 1609, freeing the connector controller for use in extending other calls.
Responsive to the restoration of chain relay 1609, its break contacts 2 complete the ringing circuit and ringing current is supplied between the tip conductors and ground to signal the desired party; its make contacts 5 and 6 remove the ground from the digit wires; and its make contacts 7 open the initial operating circuit of the hold magnet associated with the calling connector. The hold magnet is held operated from the ground on sleeve conductor S.
The Called Line Tests Busy Assuming that the called line is busy, the sleeve conductor of the called line has ground potential thereon from the connector in use and this ground appears on the sleeve conductor short-circuiting the upper winding of test relay 1611, preventing its operation.
Responsive to the failure of test relay 1611 to operate, after a slight delay, the ground potential on the busy lead BU, originating at the cit-normal contacts of the operated hold magnet, is extended through break contacts 5 of the unoperated test relay to the battery-connected winding of busy relay 1610.
Busy relay 1610 operates, and at its contacts 1 applies busy tone to the calling line through the tonecoupling condenser 1617. Its make contacts 2 extend the ground potential from make contacts 3 of release auxiliary relay 1605, through make contacts 2 of relay 1610 locking it operated. Break contacts 3 of the busy relay 1610 opens the operate circuit of the upper winding of test relay 1611 and at break contacts 4 free the chain, thereby releasing the common equipment.
Responsive to the receipt of busy tone, the calling subscriber disconnects and the connector and preceding apparatus is restored to normal.
Called Line Answer Ring-trip relay 1608, whose winding is included in the ringing circuit does not operate before the call is answered for each ringer (not shown) on the called line has the usual condenser in series therewith to block direct-current flow and because the shading collar surrounding the armature end of the core, keeps it from responding to the alternating ringing current.
In order to permit ring-trip relay 1603 to be operated by direct-current flow during the application of ringing current (if the call is then answered), the applied frequency of ringing current is in series with (superimposed upon) the exchange battery.
When the call is answered at the called station on the called line, the closure of the usual talking bridge across the called line causes direct-current flow thereover from the generator battery lead GEN-BATT, operating ringtrip relay 1608. Relay 1608 closes its make contacts to apply ground potential to the battery-connected winding of ring-cutoff relay 1606.
Ring-cutoff relay 1606 operates and at its make-break contacts 1 disconnects ringing tone from the calling line; its make contacts 2 and 3 transfer the tip and ring condoctors of the called line from the ringing current and extends the talking bridge across the ground and battery connected windings of back-bridge relay 1603, thereby supplying transmitter current to the called line; its break contacts 4 restore ring-reverse relay 1607 and its make contacts 5 lock ring-cutoff relay 1606 operated to the ground on locking conductor 1626. Ring-trip relay 1603 restores, its operate circuit being opened by contacts 2 and 3 of restored ring-cutoff relay 1606.
The transmitter current flow through the windings of relay 1603 cause it to operate and at its contacts 1 to remove the ground from the ring-start wire RI-ST; its contacts 2 close an operate circuit for reverse-battery relay 1601; and at its break contacts 3 opens the pulsing wire 1625.
Answered Supervision The relay 1601 operates and at its contacts 4 maintains an additional ground on locking conductor 1626, rendering the connector last-party release. Its contacts 1 and 2 reverse the tip and ring conductors of the calling line performing any required supervisory function, and at its contacts 3 opens the idle indicating battery supply wire.
During conversation the following relays of connector 1600 are operated:
(l) Reverse-battery relay 1601 (2) Line relay 1602 (3) Back-bridge relay 1603 (4) Release relay 1604 (5) Release auxiliary relay 1605 (6) Ring-cutoff relay 1606 (7) Test relay 1611 (8) Off-normal relay 1614 Additionally, the three counters SEQ, TR, and UR are held operated by residual magnetism.
Clearout 7 bridge relay 1603 restores, and restores reverse-battery relay 1601. With the restoration of relay 1601, ground is removed from locking wire 1626 and all operated relays restore with the exception of oifnormal relay 1614 which is maintained operated by contacts 1 of the counters, the counters being held operated by residual magnetism.
At the time when all relays are restored excepting offnormal relay 1614 which is maintained operated by contacts 1 of any of the impulse counter devices, a clearout circuit for all counters is prepared.
Ground potential from break contacts of the line relay 1602 is extended to wire 1627 through break contacts 3 of relays 1603 and 1605. This ground is further extended through the back contacts 2 of relay 16111, break contacts 1 of ring-reverse relay 1607, the winding of ring-trip relay 1608, break contacts 2 of chainrelay 1609', break contacts 6 of test relay 1611 to wire 1635 from whence it is extended through make contacts 1 of off-normal relay 1614 to battery through the restoring windings of the counters SEQ, TR and UR in series. The magnetic flux generated by the current flow through the restoring windings is in opposition to the residual magnetism thereby each counter restores.
Responsive to the restoration of each of the magnetic impulse counters, the operate circuit of the off-normal relay 1614 is opened, restoring it. With the restoration of the off-normal relay 1614, the knock-down or restoration circuit of the counters is opened at contacts 1 and resistor 1619 is again connected to wire 1633.
PBX Service As will be described in detail hereinafter, certain lines of this exchange may be arranged to provide PBX service, these lines having certain tens digits assigned thereto. When calling a PBX group, the tens digit assigned PBX service is followed by the dialing of the units digit 1, else the call will be extended to the called line whether a PBX line or not. This operation will be described in connection with the connector controller.
Under conditions when all lines in a called PBX group are busy, ground is returned on the PBX busy lead PBX-BUSY and is extended through make contacts 1 of the operated chain relay to operate busy relay 1610 which functions thereafter as previously described.
CONNECTOR CONTROLLER AND CONNECTOR SWITCH The operation of connector controller 1700 of FIGS. 3 and 4 and of the associated connector switches (FIG. 5) will now be described in detail.
One connector controller is provided to serve the one hundred lines associated with five connector switches of any switch group. The connector controller functions to connect associated calling connectors with called lines on a one-at-a-time basis. The illustrated connector controller is assumed to be associated with switch group SG- of connector frame CSF-l, FIG. 1, of which the first switch is shown in FIG. 5.
Purpose and Arrangement The purpose of connector controller 1700 is to control the crossbar connector switch 1900' in connecting the calling connectors, such as connector 1600, to called lines.
Connector controller 1700 comprises PBX relays 1750 and connector switch connector relays 1850 suitably interconnected with each other and associated with the five connector switches of a switch group, one such switch being shown in FIG. 5, to perform the necessary switching operation in extending calls to called subscriber and PBX lines.
General Operation On calls starting from the normal cleared out condition, the general operation of connector controller 1700 is as follows: 1
Assuming the connector switch 1900 shown in FIG. 5
is connector switch CSS-46 ofswitch group SG-10 of connector switch frame CSF-l, as noted in FIG. 1, the lines having the tens and units digits ending in 01 to 09 and 10 to 19 are served by such switch.
When the calling line has completed the dialing of the directory number of the called line, assuming that the ground on the selected one of the tens digit wire is transmitted to the winding of the upper or lower select magnet of the switch serving the called lines having the tens digit dialed, such magnet operates and grounds the units lock I I ofi-normal lead UL ON. This lead extends to the windings of the associated connector switch connect relays,
vthere being five such groups of switch-connect relays,
one group for each switch.
Ground appearing on the units lock off-normal lead UL-ON causes the connect relays associated with switch 1900 to operate and close the select magnet and hold magnet leads through to the magnets of the connector switch.
Ground on the units digit leads from the units register UR is transmitted to the winding of the select magnet associated with the called line.
The select magnet associated with the double horizontal serving two lines, including the called line, operates and together with the operation of either the upper or lower select magnets, selects the one horizontal that serves the called line. Ground potential is placed on the secondary-ofi-normal lead SON and is extended to the connector chain relay contacts and is connected to the hold magnet operate wire HM-OP.
The lhold magnet associated with the vertical terminating the calling connector operates and closes the tip,
ring, and sleeve conductors of the called line to the tip,
ring, and sleeve conductors of the calling connector.
The off-normal contacts on the hold magnet lock the hold magnet operated to the noted ground on the lock lead L and place ground on the busy lead BU extending to the connector, as previously pointed out.
If the called line is idle, the chain relay is released thereby removing the ground from winding of'the operated auxiliary select magnet SMU or SML and from the selected one of the principal select magnet leads SM-1 to SM-10. All select magnets are deenergized, but the cross points between the verticals and horizontals and the upper or lower contact group selected by select magnets SMU or SML are held closed by the continued operation of the hold magnet.
If the called line is busy, the operation will be similar excepting that upon operation of the busy relay and consequent restoration of chain relay, the locking circuit of the operated hold magnet will be opened, thereby returning the switch to normal condition.
PBX Service Certain lines served by a connection switch are adapted for PBX service by extending the sleeve conductor of a line assigned PBX service to PBX group relays from whence they are used in determining the busy or idle condition of such lines. Two such sleeve extensions are shown in cable 1735.
Funtional Relay Groups The relays of connector controller 1700 comprise the i following functions groups: p
1) Relays 1701 through 1704, PBX grouping relays. (2) Relays 1705 to 1708, PBX control relays. (3) Relays 1709 to 17 18, PBX test relays. (4) Relays 1801 through 1815, five connector switch connect relay groups, three relays per group.
Detailed Operation the lower select magnet and the lines having the tens digit I .0 are associated with the horizontals associated with the upper select magnet. Further, connector switch CSS- 2 is assigned the tens digits 2 and 3; the third switch is assigned the tens digits 4 and 5; and so torth.
Referring now to FIG. 5 it will be observed that the tens wires T1 to T are associated with the batteryconnected windings of lower select magnet SML and upper select magnet SMU, respectively.
Assuming tens digit 0 is dialed, then following the operation of the chain relay in the calling connector, ground appears on tens digit wire T-0 and is extended to the battery-connected winding of upper select magnet SMU which operates and at its oil-normal contacts extends ground potential to the units-lock ofi-normal wire UL-ON extending over a conductor in cable group 1037 to the battery-connected windings of the connect relays 1801 to 1803, these relays being associated with the first switch.
Responsive to the ground appearing on the units-lock cit-normal wire, each of the relays 1801 to 1803 operate and close their make contacts 1 to 10.
Assuming that the units digit dialed is the digit 1, ground appears on the units digit wire U-l and is extended over an associated conductor SMC-l in cable group 1737 to contacts 1 on the connect relay 1803.
The ground on digit wire U-1 is extended through make contacts 1 of relay 1803 to the battery-connected winding of principal select magnet SM-l, such magnet being associated with the double horizontal terminating the called line.
Responsive to the operation of the upper select magnet SMU and the consequent operation'of the principal select magnet SM-l, the lower horizontal of double horizontal 1-1-1 is selected, such horizontal being associated with the called line.
The off-normal contacts of the operated principal select magnet ground the secondary-otf-normal conductor SON which, as noted, is connected to the hold magnet operate wire HM-OP through contacts 7 of the calling connector from whence it is extended through make contacts 1 of the operated switch connect relay 1801 to the hold magnet wire HM-1 extending to the battery-connected winding of hold magnet HM-1901 over conductors in cable group 1836.
The contacts 1 to 10 of relay 1801 and contacts 1 to 10 on relay 1802 serve to connect the hold magnet operate wires of each of the calling connectors associated with any switch group to the hold magnet associated with the vertical terminating such connector, in this disclosure connectors being served by the connector switches of a switch group.
Responsive to the operation of the hold magnet HM- 1901, it being associated with the vertical terminating calling connector 1600, it looks operated through its offnormal contacts to grounded lock conductor L and at its off-normal contacts 1, ground the busy lead BU, as noted.
At such time, the called line associated with select magnet SM-l and upper select magnet SMU is connected through the cross points of horizontal H1 and vertical V1 to the tip, ring, and sleeve conductors of the calling connector and the testing of the called line is performed in the manner previously described.
Upon finding such line idle, the chain relay is restored thereby disconnecting the secondary-ofi-normal wire SON from the hold magnet wire HM-OP and removing the ground from the tens and units digit wires T-0 and U-1, thereby permitting the auxiliary select magnet SMU and principal select magnet SM-l to restore. At this time, however, the indicated cross points of horizontal H1 and vertical V1, together with the contacts associated with the upper select magnet are maintained closed as long as hold magnet HM-1901 is operated. The initial operate circuit of hold magnet HM-1901 is opened but it does not restore as ground from lock conductor L of calling connector 1600 maintains it operated.
With the restoration of the principal and auxiliary select magnets, the operating ground potential is removed from PBX Service It has been chosen to provide certain ones of the lines whose directory number tens digit is 1, 2, 3, or 4, for PBX service.
Referring now to FIG. 5, it will be observed that the lines associated with the horizontals H1 and H2 and associated with the lower select magnet are arranged in a PBX group by connecting an extension of the sleeve conductor to the PBX grouping relays of MG. 3 over conductors in cable group 1735. Accordingly, with the dialing of the tens digit 1, thereby operating the auxiliary select magnet SML and the dialing of the units digit l, thereby operating select magnet SM-l, the PBX relays 1750 are operated to extend the call to an idle line in the PBX group.
Gn completion of the dialing of the stations digit of the directory number, operation of the chain relay of the calling connector grounds the tens digit wire T-l and the units digit wire U-1, as noted. Ground appearing on the digit wire T-1 is extended to the batteryconnccted winding of the auxiliary select magnet SML and at the same time is extended over the tens extension wire "FE-1 to the battery-connected winding of the PBX grouping relay 1701.
The lower select magnet SML operates as hereinbefore described, responsive to the grounding of the associated digit wire and at its off-normal contacts, operates it associated connector switch connect relays to connect the select magnet and hold magnet wires to the coiresponding magnets of switch 1900.
Relay 1701 operates from the ground appearing on the tens extension wire T 13-1 and at its contacts 12 closes an operate circuit for units relay 1705 from the ground appearing on the units wire U-1; at its contacts 1 to 10, connects the sleeve wires of all lines serving as PBX lines (in this disclosure S1 and S2 extending to the PBX grouping relays over conductors in cable 1735) to the make contacts 1 to 10 of units auxiliary relay 1706; and at its contacts 11 connects battery through resistor 1731 to locking conductor 1722 in preparation for locking any PBX test relays that operated.
It will be observed that there is a PBX grouping relay for each of the tens digit extension wires assigned PBX service, each such relay connecting the sleeves of the lines in their respective PBX groups to the units auxiliary relay for test to determine their busy or idle condition.
Units relay 1705 operates from the ground on units digit wire U-l and at its make contacts 1 prepares an operate circuit for units auxiliary relay 1706; its make contacts 2 prepare an operate circuit for slow-operating busy relay 1708; and its break contacts 3 open the select magnet control wire SMC-l thereby delaying the operation of all select magnets until an idle line in the called PBX group is determined.
Units auxiliary relay 1706 operates and at its make contaste 1 to 10 connects the sleeve wires of the lines of switch 1900 serving as PBX lines to the ground-connected winding of the PBX test relays.
Assuming switch 1900 has two lines serving as PBX lines and assuming the first PBX line is busy, the ground potential on the sleeve conductor of the busy lines and the battery potential from the battery-connected winding of the cutoff relay of the associated line circuit of the second line are extended through the closed contacts on the PBX grouping relays and the contacts of units auxiliary relay 1706 to the ground-connected winding of the PBX test relays 1709 to 1718.
Relay 1709 is short-circuited by the grounded sleeve conductor and fails to operate but relay 1710 operates in series with the battery-connected winding of the cutoff relay. Relay 1710, at its contacts 1, locks operated to the locking battery potential on locking conductor 1722;
air lease its make contacts 2 extend ground potential to wire 1721 extending to the battery-connected winding of PBX cutoff relay 1707; and its :zrake contacts 3 exercise an order of preference in favor of the line assigned the lowest numbered PBX test relay operated.
Cutoff relay 1707 operates and at its break contacts 1 disconnects the sleeve extensions of the calling line from the PBX test relays; at its make contacts 2 disconmeets the operate circuit of the busy relay 1708, this operation being performed before the operate time of the busy relay 1708 has elapsed and extends ground potential from make contacts 2 of units relay 1705 through break contacts 3 of relay 1709 and make contacts 3 of relay 1710 to the select magnet control wire SMC-Z extending to the select magnet associated with the second line in the calledPBX group.
Select magnet SM-Z operates and at its cit-normal contacts grounds the secondary-ofi-normal wire SON,
.which as previously described, is extended through contacts on the chain relay of the calling connector to operate the hold magnet associated with the vertical terminating such connector. At such time, the calling line is connected to the called line, such called line being the second line of the PBX group, and the connector controller is cleared out as previously described.
In the event that no PBX lines are idle, cutoff relay 1707 fails to operate and ground from make contacts 2 of units relay 1705 is extended to: the battery-connected winding of slow-operate busy relay 1708 for a substantial fraction of a second and causes this relay to operate.
Responsive to the operation of busy relay 1708, ground potential is placed on the PBX-BUSY lead extending to the calling connector. As previously described, the busy relay of the calling connector operates and supplies busy tone to the calling line.
Responsive to the removal of ground from the units and tens digit wires upon extension of the calling line to the called line and the consequent restoration of the connector chain relay, units relay 1705 restores and the operated one of the PBX grouping relays restore, thereby completely clearing out the PBX relays 1-750. Upon the restoration of the principal and auxiliary select magnets on completion of the call extension, ground is removed from the units lock off-normal wire and the operated connector switch connect relays are restored.
The connector controllear 1700 is now restored to common use in preparation for calls from other connectors.
While we have described above the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only l4 horizontals and having vertical multiples corresponding respectively to the trunks, hold magnets corresponding respectively to the vertical multiples, principal select magnets corresponding respectively to the horizontal multi on -the respective verticals of each switch, control means common to said trunks, means controlled over any trunk for operating said control means in accordance with the tens and units digits of any desired called line, said control means including means for selecting the switch terminating the called line according to the called tens digit and for operating the one of the auxiliary select magnets thereof which correspond to such tens digit, the control means further including means for operating the principal select magnet which corresponds to the called units digits and means for operating the hold magnet or" the selected switch which corresponds to the last said trunk to complete a connection to the called line according to which auxiliary select magnet and which principal select magnet have been operated.
2. In a switching system according to claim 1, the said control means including means for directly operating the auxiliary select magnet which corresponds to the called tens digit, twenties relays associated respectively to said crossbar switches, means responsive to the said operation of either auxiliary select magnet of a switch for operating the associated twenties relay, and means controlled by the operated twenties relay for rendering the principal select magnets of the associated switch responsive according tothe units digit of the called line.
3. In a switching system according to claim 2, further means controlled by any said twenties relay for selecting for operation the hold magnet of the selected switch which corresponds to the trunk over which the call in progress was received.
4. In an automatic telephone system according to claim 3, said trunks having respective individualizing relays and means for operating any one of them to temporarily individualize the associated trunk with the com mon equipment, the said means for operating :any hold magnet including contact means of an operated individualizing relay in series with contact means of an operated twenties relay, and a by-passing maintaining circuit for any operated hold magnet.
References Cited in the file of this patent UNITED STATES PATENTS 2,038,222 King Apr. 21, 1936 2,672,520 Vos Mar. 16, 1954 2,773,128 Hutton et al Dec. 4, 1956 2,816,961 Jones Dec. 17, 1957
US810158A 1953-01-06 1959-04-30 Direct-access crossbar-switch connector system Expired - Lifetime US3046352A (en)

Priority Applications (20)

Application Number Priority Date Filing Date Title
US329802A US2725428A (en) 1953-01-06 1953-01-06 Multi-group primary-secondary-spread crossbar telephone system
US359761A US2909611A (en) 1953-01-06 1953-06-05 Multi-group direct-access crossbar telephone switching system
US369342A US2700071A (en) 1953-01-06 1953-07-21 Switching system using condenser storage of digits
FR1108099D FR1108099A (en) 1953-01-06 1953-07-30 Crossbar telephone system, divided into primary and secondary
DEM19699A DE971474C (en) 1953-01-06 1953-08-13 Circuit arrangement for telecommunication, in particular telephone systems
GB26448/53A GB731779A (en) 1953-01-06 1953-09-25 Multi-group primary-secondary-spread crossbar telephone system
FR53127A FR72907E (en) 1953-01-06 1954-01-06 Crossbar telephone system divided into primary and secondary
FR53194A FR72908E (en) 1953-01-06 1954-01-20 Crossbar telephone system divided into primary and secondary
FR53800A FR72909E (en) 1953-01-06 1954-06-04 Crossbar telephone system divided into primary and secondary
BE529343D BE529343A (en) 1953-01-06 1954-06-04
CH337574D CH337574A (en) 1953-01-06 1954-06-05 Direct access telephone switching installation
DEI8748A DE945257C (en) 1953-01-06 1954-06-05 Switching system with switches based on the crossbar principle
CH329942D CH329942A (en) 1953-01-06 1954-07-20 Circuit arrangement for free selection processes in telecommunication systems, in particular telephone systems
FR54017A FR72910E (en) 1953-01-06 1954-07-21 Crossbar telephone system divided into primary and secondary
US447970A US2878320A (en) 1953-01-06 1954-08-05 Circuit arrangement for telecommunication systems, in particular telephone systems
FR54100A FR72911E (en) 1953-01-06 1954-08-11 Crossbar telephone system divided into primary and secondary
BE531123D BE531123A (en) 1953-01-06 1954-08-23
US551192A US2929881A (en) 1953-01-06 1955-12-05 Terminal-per-station telephone partyline switching system
FR58041A FR72922E (en) 1953-01-06 1956-12-04 Crossbar telephone system divided into primary and secondary
US810158A US3046352A (en) 1953-01-06 1959-04-30 Direct-access crossbar-switch connector system

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US329802A US2725428A (en) 1953-01-06 1953-01-06 Multi-group primary-secondary-spread crossbar telephone system
US359761A US2909611A (en) 1953-01-06 1953-06-05 Multi-group direct-access crossbar telephone switching system
DE329942X 1953-08-13
US810158A US3046352A (en) 1953-01-06 1959-04-30 Direct-access crossbar-switch connector system

Publications (1)

Publication Number Publication Date
US3046352A true US3046352A (en) 1962-07-24

Family

ID=32398035

Family Applications (6)

Application Number Title Priority Date Filing Date
US329802A Expired - Lifetime US2725428A (en) 1953-01-06 1953-01-06 Multi-group primary-secondary-spread crossbar telephone system
US359761A Expired - Lifetime US2909611A (en) 1953-01-06 1953-06-05 Multi-group direct-access crossbar telephone switching system
US369342A Expired - Lifetime US2700071A (en) 1953-01-06 1953-07-21 Switching system using condenser storage of digits
US447970A Expired - Lifetime US2878320A (en) 1953-01-06 1954-08-05 Circuit arrangement for telecommunication systems, in particular telephone systems
US551192A Expired - Lifetime US2929881A (en) 1953-01-06 1955-12-05 Terminal-per-station telephone partyline switching system
US810158A Expired - Lifetime US3046352A (en) 1953-01-06 1959-04-30 Direct-access crossbar-switch connector system

Family Applications Before (5)

Application Number Title Priority Date Filing Date
US329802A Expired - Lifetime US2725428A (en) 1953-01-06 1953-01-06 Multi-group primary-secondary-spread crossbar telephone system
US359761A Expired - Lifetime US2909611A (en) 1953-01-06 1953-06-05 Multi-group direct-access crossbar telephone switching system
US369342A Expired - Lifetime US2700071A (en) 1953-01-06 1953-07-21 Switching system using condenser storage of digits
US447970A Expired - Lifetime US2878320A (en) 1953-01-06 1954-08-05 Circuit arrangement for telecommunication systems, in particular telephone systems
US551192A Expired - Lifetime US2929881A (en) 1953-01-06 1955-12-05 Terminal-per-station telephone partyline switching system

Country Status (6)

Country Link
US (6) US2725428A (en)
BE (2) BE529343A (en)
CH (2) CH337574A (en)
DE (2) DE971474C (en)
FR (7) FR1108099A (en)
GB (1) GB731779A (en)

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Also Published As

Publication number Publication date
BE531123A (en) 1957-11-08
CH329942A (en) 1958-05-15
FR72908E (en) 1960-09-21
FR1108099A (en) 1956-01-09
US2700071A (en) 1955-01-18
CH337574A (en) 1959-04-15
FR72911E (en) 1960-09-21
DE945257C (en) 1956-07-05
US2725428A (en) 1955-11-29
FR72909E (en) 1960-09-21
FR72910E (en) 1960-09-21
US2909611A (en) 1959-10-20
GB731779A (en) 1955-06-15
DE971474C (en) 1959-02-05
US2878320A (en) 1959-03-17
FR72907E (en) 1960-09-21
FR72922E (en) 1960-09-21
BE529343A (en) 1957-05-24
US2929881A (en) 1960-03-22

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