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US3487171A - Circuit arrangement for selecting a telephone extension by selector keys - Google Patents

Circuit arrangement for selecting a telephone extension by selector keys Download PDF

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Publication number
US3487171A
US3487171A US499837A US3487171DA US3487171A US 3487171 A US3487171 A US 3487171A US 499837 A US499837 A US 499837A US 3487171D A US3487171D A US 3487171DA US 3487171 A US3487171 A US 3487171A
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US
United States
Prior art keywords
relay
selecting
key
extension
relays
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
US499837A
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English (en)
Inventor
Winfried Schuberth
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.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
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 International Standard Electric Corp filed Critical International Standard Electric Corp
Application granted granted Critical
Publication of US3487171A publication Critical patent/US3487171A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/002—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems
    • H04M9/005—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems with subscriber controlled access to an exchange line
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/58—Arrangements providing connection between main exchange and sub-exchange or satellite
    • H04Q3/62—Arrangements providing connection between main exchange and sub-exchange or satellite for connecting to private branch exchanges
    • H04Q3/625—Arrangements in the private branch exchange

Definitions

  • the invention relates to circuitry for key-controlled telephone systems and particularly for relatively small subscribers systems with extension stations. It is an object of the invention to enable a selection by keys between at least ten different lines by remote control with very simple means. Different from the previously known key-operated selectors the selecting signals are not audiofrequency signals generated in each extension station by a separate audiofrequency generator and transmitted to the receiver in the central station. Instead the central station equipment transmits a general selection signal to the controlling extension station where digit keys are operated to modify this select-ion signal for utilization by the receiving equipment in the central station.
  • the circuitry according to the invention differs also from the previously known key selection methods using direct current mainly in that in the latter the polarity of the control wires is sensed in chronological succession by complicated and expensive relay devices
  • the invention uses low-frequency alternating current which is e.g. derived from the public supply system and stepped down as a control current or general selection signal so that the previously required expenditure is avoided.
  • Another advantage of this circuitry is the direct setting of the line-selecting relays. This enables the selective connection of' up to ten two-wire lines to the central station equipment by only four relays.
  • the circuitry enables also the selection of one of ten extension stations by the use of only four keys in each extension station provided that the connection to each of the extension stations is established by two key depressions. Each key has only a single change-over Contact.
  • the circuitry according to the invention for selecting a conversation partner by selecting keys is characterized in"that an ⁇ alternating current source is provided in the central station and two series-connected selecting key contacts are provided in each speech wire in each extension station, the voltage of the alternating current source is applied to each speech wire by a contact, which is indirectly closed by the depression of any desired selecting key, and two relays lassociated with each wire and bypassed each by a rectifier, which rectiers are connected in phase opposition, and the alternating current flows through the respective closed selecting key contacts and one of two phase-opposed rectiers back to the alternating current source, so that the closing of a certain selecting key contact causes a certain relay to pick up and prepare the speech channel with its Contact (after the first depression of a key) and to establish the speech channel (after the second depression of a key).
  • the central station is provided with a relay which is responsive to the alternating current source and connected in the diagonal of a rectifying bridge.
  • an engaging relay energiZa-ble by the cradle s-Witch, a time-limit relay, a changeover rel-ay, a rel-ay for signalling the first selection and a relay for signalling the second selection are provided.
  • each of the selecting relays has a second winding, which is self-holding by a separate contact during the conversation.
  • the alternating current source is preferably the lighting supply system (50 Hz).
  • FIG. 1 shows the application of the invention to a subscribers system with ten extensions.
  • the finder When the receiver in one of the extension stations is lifted, the finder is adjusted to this extension station. (The adjusting means are not shown).
  • the windings SPI and SPII of relay SP are energized through the extension station loop and relay V through the contact sp1. It may be assumed, for instance, that the extension station 34 is selected from an extension station TN. In extension station TN, the key 3T is briefly depressed. This will interrupt the speech loop and cause the relay SP to drop out.
  • Relay U is energized through contacts sp3. By contacts u1 and u2, relays A and B are connected to the a-wire and relays C and D to the b-Wire.
  • the general selection signal consisting of 4an A.C. Voltage of 50 ⁇ cycles is applied to the speech wires by contact V1 and the four relay windings AI, BI, CI and DI.
  • Relay X serves for indicating whether a key is depressed and is energized as long as any of the four keys 1T to 4T is depressed.
  • Contact x3 energizes relay SP in SPIII and holds U in UII because the first winding of U is de-energized when sp3 is open.
  • V does not drop out during the selecting operation ⁇ because its release is delayed by K1 and R4 and because it is held by the contact x1 immediately when X has picked up.
  • the release of relay U is delayed by G111. This delay of the release is required to ensure an energization of relay R after the first depression of a key.
  • Relay R is energized through x2 in its inoperative position and through uS n its operative position and holds by its own contact r2.
  • relay R records that the first selection has been performed.
  • relays SP, V, C, R are energized. Now the key 4T is depressed.
  • the relays X and D are energized in circuit (4).
  • Relay S is energized through the closed contact r1 to indicate that the second selection has been performed.
  • Circuits for selecting one station from among a plurality of telephone extension stations through operation of selection keys at a first extension station comprising an alternating current source coupled to rectifier means to provide positive and negative halfwaves, two speech wires for interconnecting the extension stations, two selecting key contacts (1T, 2T, 3T, 4T) provided in series with each speech wire in each extension station, means closing a normally open separate contact (v1) in response to lifting of a receiver at the first extension station, said separate contact coupling the positive and negative half-waves provided by the rectifier means to first terminals of two pairs of relays (A1, B1, C1, D1), means connecting each pair of relays in series between said separate contact and a respective normally open relay Contact (u1, u2), means coupling a rectifier (GL3, GL4; GLS, GL6) in parallel with each Of said relays, said rectifiers forming circuits in phase opposition to each other to serve as by-pass paths for current in different directions so that the half-waves can flow only through one relay and one of
  • circuits as claimed in claim 1 in which the means closing the normally open separate contact (v1) in response to lifting of a receiver includes an engaging relay (SP) connected to operate as the receiver is lifted, said engaging relay closing a plurality of contacts to cause the operation of a time limit relay (V) and thus close the open separate contact.
  • SP engaging relay
  • V time limit relay

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Astronomy & Astrophysics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)
  • Telephonic Communication Services (AREA)
US499837A 1964-11-04 1965-10-21 Circuit arrangement for selecting a telephone extension by selector keys Expired - Lifetime US3487171A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT932764A AT245055B (de) 1964-11-04 1964-11-04 Schaltungsanordnung zum Wählen eines Gesprächspartners mittels Wähltasten

Publications (1)

Publication Number Publication Date
US3487171A true US3487171A (en) 1969-12-30

Family

ID=3613179

Family Applications (1)

Application Number Title Priority Date Filing Date
US499837A Expired - Lifetime US3487171A (en) 1964-11-04 1965-10-21 Circuit arrangement for selecting a telephone extension by selector keys

Country Status (4)

Country Link
US (1) US3487171A (de)
AT (1) AT245055B (de)
DE (1) DE1283923B (de)
GB (1) GB1058540A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3697704A (en) * 1969-10-02 1972-10-10 Gen Electric Co Ltd Circuits for private automatic telephone exchange systems

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2852488C2 (de) * 1978-12-05 1982-05-06 Standard Elektrik Lorenz Ag, 7000 Stuttgart Schaltungsanordnung zur Auswertung von codierten Gleichstromtastwahlkennzeichen in Fernsprechanlagen mit unterschiedlich langen Teilnehneranschlußleitungen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2278410A (en) * 1940-10-08 1942-04-07 Bell Telephone Labor Inc Telephone system
US2400148A (en) * 1943-06-23 1946-05-14 Bell Telephone Labor Inc Telephone call transmitting device
US3328533A (en) * 1964-06-18 1967-06-27 Columbia Ribbon & Carbon Direct key calling telephone station having binary converting means

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2278410A (en) * 1940-10-08 1942-04-07 Bell Telephone Labor Inc Telephone system
US2400148A (en) * 1943-06-23 1946-05-14 Bell Telephone Labor Inc Telephone call transmitting device
US3328533A (en) * 1964-06-18 1967-06-27 Columbia Ribbon & Carbon Direct key calling telephone station having binary converting means

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3697704A (en) * 1969-10-02 1972-10-10 Gen Electric Co Ltd Circuits for private automatic telephone exchange systems

Also Published As

Publication number Publication date
AT245055B (de) 1966-02-10
GB1058540A (en) 1967-02-15
DE1283923B (de) 1968-11-28

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