US2212177A - Automatic telephone system - Google Patents

Automatic telephone system Download PDF

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Publication number
US2212177A
US2212177A US173697A US17369737A US2212177A US 2212177 A US2212177 A US 2212177A US 173697 A US173697 A US 173697A US 17369737 A US17369737 A US 17369737A US 2212177 A US2212177 A US 2212177A
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US
United States
Prior art keywords
line
link
lines
voltage
subscriber
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
US173697A
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English (en)
Inventor
Hullegard Erik Waldemar
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.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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 Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Application granted granted Critical
Publication of US2212177A publication Critical patent/US2212177A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/42—Circuit arrangements for indirect selecting controlled by common circuits, e.g. register controller, marker
    • H04Q3/52—Circuit arrangements for indirect selecting controlled by common circuits, e.g. register controller, marker using static devices in switching stages, e.g. electronic switching arrangements
    • H04Q3/525—Circuit arrangements for indirect selecting controlled by common circuits, e.g. register controller, marker using static devices in switching stages, e.g. electronic switching arrangements using tubes in the switching stages

Definitions

  • a subscriber AI is connected to the exchange over a two-wire line ALI and AL2.
  • each wire of the line is connected in multiple to electrodes I of paths or tubes UI a number of discharge and U2, the other electrodes 2 of which are connected to a two-wire link line FLI and FLZ within the exchange.
  • each one of the two branches of the subscribers line is also connected at a point 5 or 6 respectively over a resistance rI or T2 respectively to the plus-pole or minus-pole respectively of a battery El.
  • each branch a resistance T3 or 14, which is connected in parallel with a condenser CI or C2, is included between the electrode I and the 6 for the battery.
  • connecting point 5 and two branches of the link line are connected over resistances r5 and T6 to the plus-pole and second battery E2.
  • the voltage of the battery E2 differs from the voltage of the battery El.
  • the current passing through the resistance TI causes a drop of voltage resulting in a reduction in potential at the point 5 where the battery El is connected to the subscribers line ALI.
  • the resistance TI is so dimensioned that said reduction of voltage will be sufficient to increase the voltage difference between the subscribers line ALI and the link line FLI to the ignition voltage for a discharge path UI. Since the two branches of the subscribers line are connected in multiple with a plurality of pairs of discharge paths special provisions must be made to insure connection between the other branch ALZ of the subscribers line and the branch FL2 of the same link line. For this purpose, discharge paths having different ignition voltages can be provided, for example, in the same sequence for both branches of the diiferent subscribers lines.
  • the ignition of one discharge path UI can be made to cause ignition of the corresponding discharge path U2, in that for example provisions can be made to ensure that the voltage E2 is applied on the corresponding link line branch only after the path UI has been ignited and the line FLI energized. Ignition of both paths UI and U2 completes the connection between the subscribers line and a link line in the exchange.
  • the current now set up changes the potential of the wire so that no other subscribers line can be connected to the same link line, the current through the resistance r2 raising the voltage of the electrode l and of the electrodes connected in multiple therewith to such a degree that none of the discharge paths to which said latter electrodes appertain can be ignited.
  • the switching operations taking place upon a call intended for a subscriber AI are the following.
  • a register or other switching device actuated upon a call from a subscriber by the numerical impulses marks in ordinary manner over lines ML the pair of discharge paths UI and U2 which connect the calling link line with the desired subscribers line.
  • Over the marking lines ML the potential on the grids 3 of the discharge paths is changed so that said paths are ignited. Said marking occurs only during a brief moment.
  • a ringing signal can be transmitted to the subscriber AI by generating oscillations in the tubes UI and U2, for example in cooperation with 'condensers and resistances, or by connecting a suitable ringing current source to the link line.
  • a connection can also be set up from a link line to a subscribers line by changing the potential on the branches of the link line and by simultaneously changing the grid potentialin the corresponding discharge paths. The ignition of the discharge paths is then brought about through co-operation between said two changes of potential.
  • a telephone exchange comprising, link lines at said exchange and subscriber lines connected to said exchange, discharge paths arranged between the corresponding speaking wires of said link lines and subscriber lines, a current source of certain voltage connected to each speaking Wire of a subscriber line over resistances, a second current source of another voltage connected to each wire of the link lines, the voltage difference between said current sources, being so determined that an increase of said voltage difference will cause ignition of the discharge paths to provide a direct connection between a link line and a subscriber line over said discharge paths, a resistance and a condenser arranged in parallel in each branch of a subscriber line between electrodes of the discharge paths and the points on the line in which the current source is connected.
  • a telephone exchange comprising, link lines at said exchange and subscriber lines connected to said exchange, discharge paths arranged between the corresponding speaking wires of said link lines and subscriber lines, a current source of certain voltage connected to each speaking wire of a subscriber line over resistances, a second current source of another voltage connected to each wire of the link lines, the voltage difference between said current sources being so determined that an increase of said voltage difierence Will cause ignition of the discharge paths to provide a direct connection between a link line and a subscriber line over said discharge paths, a grid in each discharge path, means for simultaneously changing the potential on the branches of the link line and the potential of the grids belonging to the discharge paths between said linkline and a subscribers line whereby the discharge paths are ignited upon a call from said link line to said subscriber line.
  • a telephone exchange com-prising, link lines at said exchange and subscriber lines connected to said exchange, discharge paths arrange-d between the corresponding speaking Wires of said link lines and subscriber lines, a current source of certain voltage connected to each speaking wire of a subscriber line over resistances, a second current source of another voltage connected to each wire of the link lines, and the voltage difference between said current sources being so determined that an increase of said. voltage difference will cause ignition of the discharge paths to provide a direct connection between a link line and a subscriber line over said discharge paths.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Telephonic Communication Services (AREA)
  • Interface Circuits In Exchanges (AREA)
US173697A 1936-11-14 1937-11-09 Automatic telephone system Expired - Lifetime US2212177A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE2212177X 1936-11-14

Publications (1)

Publication Number Publication Date
US2212177A true US2212177A (en) 1940-08-20

Family

ID=20424982

Family Applications (1)

Application Number Title Priority Date Filing Date
US173697A Expired - Lifetime US2212177A (en) 1936-11-14 1937-11-09 Automatic telephone system

Country Status (2)

Country Link
US (1) US2212177A (en:Method)
DE (1) DE715550C (en:Method)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE509052A (en:Method) * 1951-02-23

Also Published As

Publication number Publication date
DE715550C (en:Method)

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