US1899551A - Automatic telephone system - Google Patents

Automatic telephone system Download PDF

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Publication number
US1899551A
US1899551A US495591A US49559130A US1899551A US 1899551 A US1899551 A US 1899551A US 495591 A US495591 A US 495591A US 49559130 A US49559130 A US 49559130A US 1899551 A US1899551 A US 1899551A
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US
United States
Prior art keywords
trunk
relay
switch
tube
trunk line
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US495591A
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English (en)
Inventor
John I Bellamy
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.)
Associated Electric Laboratories Inc
Original Assignee
Associated Electric Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Associated Electric Laboratories Inc filed Critical Associated Electric Laboratories Inc
Priority to US495591A priority Critical patent/US1899551A/en
Priority to DER82416D priority patent/DE590869C/de
Priority to GB2669131A priority patent/GB389840A/en
Application granted granted Critical
Publication of US1899551A publication Critical patent/US1899551A/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
    • H04Q3/0016—Arrangements providing connection between exchanges

Definitions

  • This invention relates to automatic telephone systems in general, and more particularly to holding arrangements for use at the outgoing end of inter-office trunk lines which are of suciently lowresistance so that im' pulse repeaters ⁇ are not required.
  • the main object of the present invention is the provision of an improved holdingV arrangement which eliminates the series relay does not adect the quality of I q impulse and vvoice transmissiony over the trunk line and which, moreover may be used in trunk lines wherein series holding devices will not function becauseof the discontinuation of the current ow at some stage of the connection.l l v
  • the above object is attained in the present invention by bridging the grid-filament circuit of alvacuum tube across the two conductors of an outgoing trunk line and providing relays, controlled by the vacuum tube,
  • the selector S is ofthe well known Strowger switch type having a directive vertical movement and an automatic rotary movement.
  • the selector VS may beV accessible to other local selectors in the same exchange, lto incoming :selectors terminating trunks from other exchanges in cases where the exchange in which the selector S is located is used as a tandem exchange, or ⁇ directly to subscribers lineswitches.
  • the selector S has ent invention, and serves to 4furnish ⁇ a holding potential to hold the selector S an-dfother preceding switches operated. 1
  • rlhe vertical magnet energizes at Veach impulse and raises the switch shaft and wipers' of the selector to a point opposite the level in which the trunk lines to the desired exchange are accessible.
  • vertical oil-normal springs 31 and 35 are closed.
  • vertical oil-normal Vsprings 31 a point is closed in the release, circrates in this circuit and at armature and cuit for itselt' independent of the contacts on the series relay 15, andat armature 22 and kits working contact prepares a circuit for the rotary magnet 38.
  • the operation new depends upon whether or not the trunk line accessible in the first set of contacts in theselected level is busy. If this trunk Vlineis busy there will be ground potential present on the bank contact engaged by wiper 37 and this ground potential shunts tlie switching relay 25 and again completes the circuit of the stepping relay 2O over armature 29 and its resting contact, vertical oft-normal springs 35, interrupter springs 34 of the rotary magnet 33, winding of stepping relay 2O to battery.
  • Relay 20 energizes and at armature 22-and its'wo'rking contact again completes the circuit to the rotary magnet, and the above operations are again repeated.
  • the selector switch is rotated in the above manner until the wipers encounter an idle trunk line. It will be assumed that the trunk line comprising conductors 76 and 77 and accessible to the selector switch over bank contacts'39, 40, and 41 is idle. Vlli/'hen the wipers of the selector switch are moved into engagement with these bank contacts, wiper 37 does not encounter ground potential and the switching relay 25 is no longer shortcircuited. As soon as the rotary magnet 33 ,deener'gizes and closes its interrupter springs 34 a circuit is completed for switching relay 25 extending from ground at the working contact of armature l1 and said armature, winding lof switching.
  • relay 25 vertical ofi'- normal springs 35, rotary interrupter springs 34C, winding of relay 20 to battery.
  • Relay 25 operates in this circuit but due to the high resistance of this relay, the relay 20 will not operate in series.
  • relay 25 removes ground from the armature of the line relay 5 in order to prevent the release of the switch when the line and release relays deenergize.
  • the line relay 5 is disconnected and at the working contacts of these armatures the calling subscribers loop is extended over wipers 36 and 38 and bank contacts 39 and 4:1 to the trunk line ext-ending to the desired ex# change.
  • armature V29 and its working contact the Vrelease trunk is extended to the holding trunk HTV over wiper 37 and bank contact 40.
  • Relay deenergizes due toits disconnection from the calling loop at armatures 26y and 27, and at armature 6 and its working contact opens a point in the circuit of release relay l() and at its resting Contact closes a oint in the circuit of release magnet 30.
  • elease relay l0 is slow-to-release and maintains its armature in operated position for an interval after its circuit isopened. llien this relay finallyreleases it removes ground from the release trunk conductor at-.armature ll but this ground has been replaced by ground from the holding trunk HT, aswill be explained hereinafter. At armature l2 and its resting contact, relay 10 completes a further point in the circuit of release magnet 30.
  • a plate current lows from the plate of tube 70, winding of relay 65 and the resistc ance 67 in parallel, Vsecondary winding of transformer 60, V ⁇ to the filament of the tube.r
  • This plate current operates the relay 65 which at armature 66 and its working contact connects ground tothe Windingof relayl 55 to operatethis relay.
  • YRelay 55 at armature 56 and its workingV contact connects.
  • Plate relay 65 is made slow-torelease by the resistance 67 in multiple with its winding so that it will not release during ⁇ the'negative half cycles of the alternating current in the secondary transformer 60, and this slow-release feature also tendstokeepy therelay op erated duringv the subsequent impulsing.
  • the relay may not besuiiciently sloweacting to holdY upy duringfthek dialling offsubsequent digits andthe relay 55 is theres f fore provided with a resistance 57 in multiple with its winding so that this relay is also made slow-to-release. gizes during impulsing. it opensthe. circuit of relay 55 momentarily, but since this relay i is also 'slow-to'release it will ynotV open its 'contacts ⁇ during the momentary interruption of this circuit.
  • the two slow-to-release relays positively insure that ground willcnot be removed from the releasey trunk conductor during the operation of the switches in they called exchange.
  • release magnet 30 operates in this circuit and restores the switchrto its normal position.
  • a high resistance 75 is inserted .between the connection of trunk conductor 77 to the filament of tube 70. This resistance may be as high as one megohin and serves to prevent any noise from reaching the trunk lines and also to prevent any unbalancing of the trunk lines.
  • a switch 72 is provided to connect the filament of tube either to conductor 77 through resistance 75 or to connect the filament of the tube directly to ground when the switch is operated to contact 74.
  • the filament of tube 70 may be connected directly to ground and in this case a common transformer, such as 60, may beV used for all of the holding trunk circuits in the exchange.
  • the vacuum tube "i0y is controlled over conductor 76 with a ground'return circuit, instead of lover both conductors 76 and 77.
  • the potential of the biasing battery V7l is preferably increased to about three-fourths of the voltage of the exchange battery, as 'only half the change formerly produced in the grid-ilamentvoltage is now produced when the trunk line is taken for use.
  • the invention comprises V'a holdingl device which eliminates the third, ⁇ or holding, conductor of'interoflice trunk lines; which doesy not require any series relay or other resistance element in the talking conductors of the trunk line; and which is especially applicable to a system in which the current flow over the trunk line is discontinued at some stage of the connection, since the device is not dependent on current flow in the trunk line but is rendered operative as soon as the trunk line is seized and can be released only by the application of the full normal potential of .the exchange battery tothe conductors of the trunk line.
  • a trunk line a..
  • vacuum tube having its grid-filament circuit 'bridged across said trunk line, automatic switches for extending a calling line to said trunk, means .responsive to said extension for rendering said tube operative, means .fcon
  • a trunk line In a telephone system, a trunk line, a selector switch having access thereto, a test wiper in said switch, a'vacuum tube associated with said trunk line, means for operating said switch to seize said trunk line, means controlled over said test wiper for rendering said tube operative, and means controlled by said tube for maintaining said last means and said switch operated.
  • a two conductor trunk line connecting a first and a second exchange and' terminating 'in a battery in the second exchange
  • a vacuum tube in the first Y exchange having its grid circuit connected to the negative conductor of said trunk line whereby said grid is normally at a negativeV potential to render said tubeinoperative
  • means for extending a calling loop to said trunk line and means responsiveto said extension for ⁇ reducing the effect of said battery to render said tube operative.
  • a trunk line con-v necting a first and a second exchange and terminating in a battery in the second exchange, a vacuum tube in the first exchange having its grid circuit connected to the nega- ⁇ tiveiconductor of said trunk line whereby said tube is normally rendered inoperative,
  • 0 means for extending a callingVv line tosaid trunlrline, a biasing battery eective responsive to said extension for rendering said tube operative, and means controlled by said tube for Amaintaining said extending means opf 5 erated.
  • a trunk line connecting aitirst and a second exchange a vacnum tube in the first exchange having its grid cir-cuit connectedtothe negative conductor of said trunk line, means for extending a calling loop to said trunk line, a biasing battery effective when the calling loop is closed to render said tube operative, an exchange battery connected to said trunk line in the second exchange and effective to render'said tube inoperative when thecalling loop is opened, and means controlled by said ⁇ tube for supplying a holding potential to maintain said extending means operated while the calling loop is '10i closed and for removing said potential to allow said extending means to release when the calling loop is opened.
  • a trunk an automatic switch having access thereto, la vacuum 5 'tube in said trunk rendered operative by current low over the trunk when it is seized by said switch, means controlled by said tube for supplying holding potential to saidV switch, and means for maintaining'said tube and holding means operative independent of current flow over said trunk.
  • a trunk terminating in a battery, anautomatic switch having access to said trunk, means in said trunk for supplying holding potential to said switch responsive to current low over the trunk when it is seized by said switch, and means for maintaining said holding means operated independent of current flow over,
  • 121.- In a telephonesystem in which'automatic switches are employed to establish a telephone connection over a trunk line and in which all battery connections are removed Y holding circuit effective to ksupply holding potential to the switches used to vestablishV the connection, and meansgfor maintaining said holding lcircuit operative during conversation.
  • means including ⁇ a vacuuml tube responsive to current flow. over 'said trunk line when-the same is ⁇ seized yfor supplying holding potential to said switches, said means remaining operative when thefbattery connections are removed from said trunlrline and releasing to discontinue the supplyiof ⁇ holding potential only when the battery connections lare again completed tosaid trunlr line at the end or the conversation.
  • a trunk In a telephone System, a trunk, automatic switches for-establishing al connection i to said trunk, a holdingY circuit for said switches completed when the trunk is con-l nected with, a battery,;and means responsive to the application Aof the full batteryV potential to said vtrunk for opening said ,holding 1 circuit -tgo release saidswitches.
  • talking conductors means controlled by said tube for controlling said connection over said control conductor, and means controlled over erative.
  • a trunk means for establishing a connection to said trunk, a vacuum tube having its grid-filament circuit bridged across the talking conductors of said trunk, means controlled by said tube for controlling said connection, and a high resistance connected between the lament circuit of the tube and one talking conductor ,of said trunk to prevent unbalance of said trunk and interference with conversation over said trunk.
  • a trunk means for establishing a connection to said trunk, a Mholding circuit in said trunk including a va'cuum tube having its grid coupled to one talking conductor and its cathode coupled to the other talking conductor, and a high resistance connected between said'other talkming conductor and the coupling to said V cathode to prevent unbalance between said talking conductors and interference with conversation over said trunk.
  • a trunk coinprising two talking conductors, an automatic mswitch for establishing a connection to said trunk, a holding device in said trunk, athird conductor extending backrfrom said holding device to said automatic switch, and means in said device exclusive of any current con- ⁇ suming connections to the talking conductors 'of said trunk for supplying holding potential to said switch.
  • a trunk line comprising two metallic talking conductors @extending from the banks of an automatic ⁇ switch to a succeeding switch, holding equipment for thefirst switch individual to saidtrunk line, a third conductor extending back to said first switch romsaidequipment, a
  • a trunk line extending to an autcmaticswitch, means including 'a second switch for'extending a connection to said trunk line,'means in the first switch'ior supplying current over the trunk line to .a point ahead of said!
  • a trunk line comprising. two talking conductors extending exclusive of any series inductive windings or conductive bridges-from the banks of an automatic switch to a succeeding switch, a holding device individual to said trunk, a third conductor extending from said device back to said rst switch, means for supply-V ing current over the two talking conductors vfrom the second switch through the first switch to a calling bridge, and a potential operated device Yin said holding device re-4 sponsive solely to changes in potential on one of said conductors which result from changes in current iiow in the calling bridge for controlling the application of holding potential to said third conductor.
  • j 'Y 27 In a.
  • a trunkv line comprising two talking conductors extending exclusive of any series inductive windings or conductive bridges from the banks of an auto,- matic switchto a succeeding switch, a holding device individual to said trunk, a third conductor extending from said vdevice. back to said first switch, means for supplying cur-- rentto the talking conductors of said trunk line from the second'switch, and means in said device responsive to a potential in one of said talking conductors for controlling the application of holding potential to said third conductor.
  • a trunk rline to said third iso comprising two talking conductors extend'l ing excluslve of any series inductive Windings or conductive bridges from the banks of an automatic switch to a succeedingsvvitch.
  • third conductor extending from said device back to said first switch, and means including a vacuum tube insaid device having its Vgrid connected to one talking conductor for controlling the application of holding potential to said third conductor.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Devices For Supply Of Signal Current (AREA)
  • Interface Circuits In Exchanges (AREA)
US495591A 1930-11-14 1930-11-14 Automatic telephone system Expired - Lifetime US1899551A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US495591A US1899551A (en) 1930-11-14 1930-11-14 Automatic telephone system
DER82416D DE590869C (de) 1930-11-14 1931-08-09 Schaltungsanordnung fuer zweiadrigen Verbindungsverkehr in Fernsprechanlagen mit Waehlerbetrieb
GB2669131A GB389840A (en) 1930-11-14 1931-09-24 Improvements in or relating to telephone systems

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US590869XA 1930-11-14 1930-11-14
US495591A US1899551A (en) 1930-11-14 1930-11-14 Automatic telephone system

Publications (1)

Publication Number Publication Date
US1899551A true US1899551A (en) 1933-02-28

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US495591A Expired - Lifetime US1899551A (en) 1930-11-14 1930-11-14 Automatic telephone system

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US (1) US1899551A (de)
DE (1) DE590869C (de)

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DE590869C (de) 1934-01-15

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