US2291224A - Selecting system - Google Patents

Selecting system Download PDF

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Publication number
US2291224A
US2291224A US377996A US37799641A US2291224A US 2291224 A US2291224 A US 2291224A US 377996 A US377996 A US 377996A US 37799641 A US37799641 A US 37799641A US 2291224 A US2291224 A US 2291224A
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US
United States
Prior art keywords
group
tubes
switches
groups
lines
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
US377996A
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English (en)
Inventor
Nathan I Hall
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.)
AT&T Corp
Original Assignee
Bell Telephone 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
Priority to NL69254D priority Critical patent/NL69254C/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US377996A priority patent/US2291224A/en
Priority to GB2925/42A priority patent/GB549325A/en
Application granted granted Critical
Publication of US2291224A publication Critical patent/US2291224A/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

Definitions

  • This invention relates to selecting and switching systems and particularly to systems in which selections are made automatically in a group of lines, trunks, or other circuits.
  • An object of the invention is to obtain a more uniform and more eihcient use of the lines, circuits, or other elements comprising a group in which selections are made.
  • Another object is to obtain a preferential selection of circuits which varies in accordance with the-extent of their us'e.
  • Another object of the invention is to improve the eiiiciency of switching systems by obviating the selection of circuits which have no available outlets.
  • a switching system in which a plurality of equivalent groups of lines or trunks are accessible to automatic switches for extending calls or other connections, in which the several groups are selectable under the control of associated devices having varying degrees of sensitivity, and in which the selectability or preference for any particular' group of lines is varied by varying the sensitivity of the associated device in proportion to the number of calls extended to the lines of said group. More specifically the selecting system above mentioned may serve to extend subscribers lines over automatic switches to the trunks of a, plurality of groups.
  • Any line when calling, causes the application of operating voltage to a plurality of ldischarge tubes which are related respectively to the several groups of trunks, the rst tube to discharge in response to the applied voltage serving to cause the extension of the calling line to an idle trunk in the corresponding group. Since the order in which the tubes of the group operate depends upon the relative speed with which the ionizing current increases in their control gaps, it is possible to obtain a preferential distribution of the calls among the diierent trunk groups by controlling the sensitivity of said control gaps. 'I'his desirable end is accomplished by providing an impedance element for each trunk group and connectgroup becomes loaded its associated control tubes ⁇ become less sensitive, and other tubes will discharge first' to extend subsequent calls lto other groups of trunks.
  • a feature of the invention is a selecting system in which calling lines have access through links to groups of trunks, in which discharge tubes respond to calls on said lines to extend these calls over associated links to the associated trunk groups, and in which the busy condition of all telephone system to groups of links, trunks, or
  • Fig. 1 two frames of primary and secondary 'line switches are illustrated.
  • One of these frames comprises ten primary cross-bar switches of which two, switches
  • This frame also includes ten secondary line switches of which two, switches
  • 05 appear in the vertical contacts of the ing this element in common to the electrodes of all tubes which cause the extension of calls into said group.
  • Each call extended into a particular group causes an increased current to flow v ⁇ through the common impedance element, which in turn lowers the voltage on the control electrodes of all tubes serving this group. This lowered voltage renders these tubes less .sensitivel than the tubes pertaining to other groups of trunks containing lighter loads.
  • 03 have access respectively to ten groups of trunks 06-
  • Each of the ten horizontal rows of each primary switch is provided with a select magnet and a space-discharge tube.
  • 00 is provided with select magnet
  • the No. 9 horizontal row of the switch is provided with select magnet 0 and tube
  • the presence of a call on one of the subscriberslines causes the application of operating voltage to the control gaps of all tubes associated with the corresponding primary switch.
  • thev associated select magnet operates to select'the horizontal circuit or link for extending the call to the corresponding secondary switch. 4'I hereafter the voltage on all remaining tubes is reduced to prevent another one from discharging and causing a double connection.
  • the secondary switches may have access to ten separate trunk groups, or they may, as illustrated herein, have access to the trunk groups
  • the purpose of giving two or more frames access to the same trunk groups is to provide these vgroups with an adequate load. ⁇
  • the tubes disclosed herein may be of any suitable type, such asthose having .envelopes filled with'argon, neon or other gases. i.
  • Relay 202 operates and closes a circuit from ground through its contacts, conductor 200 through the winding of magnet 203, armature and back contact of'said magnet, conductor 201,resista.nce 203 to the start'v sistor 2
  • the voltage thus supplied across the control gap 20S- 2H is ing of magnet 203 tolground'at the contacts of relay 202.
  • 3 operates in this circuit, but the resistance of this relay and the resistance of element 2
  • 3 When relay 2
  • Each idle link in the group of ten links 229-230 is characterized by the presence of negative battery potential on the test conductor thereof, and busy links are characterized bythe presence of ground potential on the test conductor. For example, if link 229 is busy, ground potential is connected through the contacts Aof a suitable relay 23
  • an ionizing circuit for the tube 223 ⁇ may be traced from the positive pole of battery 222, resistor 223, contacts of relay 2
  • the control gap.228234 ionizes, and insimilar fashion the control gaps of all other tubes representing idle links ionize.
  • a circuit may be traced from the'positive pole of battery 222, resistance 223, contacts of relay 2
  • conductor 224, anode 220, cathode 230, common conductor 233, wind- .cathode 240 of tube 221 is instantly made more positive to prevent the transfer of ionization of this tube in the event the link 223 hadbeen idle.
  • prepares the switch for the selection of the idle link 230 and also closes a short circuit around the resistor 2I4.
  • 5 opens its contacts and severs the discharge circuits of the tubes 228 and 2 I0. There upon these tubes deionize, and the magnet 24
  • the trunk in one of these groups is taken for use, such as the trunk
  • ground potential is applied to the test conductor thereof, and current now ows over a circuit traceable from the negative pole of'battery
  • 29 lowers the potential on the start cathodes of all other tubes serving this group of trunks
  • is less than the voltage impressed across the starting gaps of the other nine tubes.
  • the voltage applied to the gap of tube is the sum of the full negative potential of battery I4
  • the combination in a selecting system of groupsv of circuits, discharge devices, one for each group for controlling the extension of connections to said groups, means effective as the numberof busy circuits in any group increases for decreasing correspondingly the responsiveness of the associated discharge device to increase the l preference for other groups of said circuits.
  • a selecting system ot a plurality of groups of lines, switches having access to s aid lirfes, a plurality ol" groups of discharge tubes, each group serving to Acause the extension of connections to a particular one of said groups of lines, a source ot voltage, supply circuits, .one for each group of tubes for applying voltage from said source to said tubes, means for lowering the voltage applied to any particular group of tubes in proportion to the number ot connections established to the lines ot the corresponding group, and means for opening the supply circuit of any group of tubes when all of the lines in the associated group are busy.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Devices For Supply Of Signal Current (AREA)
US377996A 1941-02-08 1941-02-08 Selecting system Expired - Lifetime US2291224A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
NL69254D NL69254C (en(2012)) 1941-02-08
US377996A US2291224A (en) 1941-02-08 1941-02-08 Selecting system
GB2925/42A GB549325A (en) 1941-02-08 1942-03-06 Improvements in or relating to automatic telephone systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US377996A US2291224A (en) 1941-02-08 1941-02-08 Selecting system

Publications (1)

Publication Number Publication Date
US2291224A true US2291224A (en) 1942-07-28

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Family Applications (1)

Application Number Title Priority Date Filing Date
US377996A Expired - Lifetime US2291224A (en) 1941-02-08 1941-02-08 Selecting system

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US (1) US2291224A (en(2012))
GB (1) GB549325A (en(2012))
NL (1) NL69254C (en(2012))

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2542672A (en) * 1948-10-27 1951-02-20 Bell Telephone Labor Inc Coordinate selecting and lockout circuit
US2562100A (en) * 1948-11-17 1951-07-24 Bell Telephone Labor Inc Coordinate selecting and lock-out circuit
US2582959A (en) * 1947-10-29 1952-01-22 Bell Telephone Labor Inc Electron-tube controlled switching system
US2594389A (en) * 1948-08-04 1952-04-29 Bell Telephone Labor Inc Double-lockout interconnecting system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2582959A (en) * 1947-10-29 1952-01-22 Bell Telephone Labor Inc Electron-tube controlled switching system
US2594389A (en) * 1948-08-04 1952-04-29 Bell Telephone Labor Inc Double-lockout interconnecting system
US2542672A (en) * 1948-10-27 1951-02-20 Bell Telephone Labor Inc Coordinate selecting and lockout circuit
US2562100A (en) * 1948-11-17 1951-07-24 Bell Telephone Labor Inc Coordinate selecting and lock-out circuit

Also Published As

Publication number Publication date
GB549325A (en) 1942-11-16
NL69254C (en(2012)) 1900-01-01

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