FR2480051A1 - Pushbutton keyboard for telephone - uses frequency generator supplied by pair of zener diodes and current source with current limiting circuit - Google Patents

Pushbutton keyboard for telephone - uses frequency generator supplied by pair of zener diodes and current source with current limiting circuit Download PDF

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Publication number
FR2480051A1
FR2480051A1 FR8007435A FR8007435A FR2480051A1 FR 2480051 A1 FR2480051 A1 FR 2480051A1 FR 8007435 A FR8007435 A FR 8007435A FR 8007435 A FR8007435 A FR 8007435A FR 2480051 A1 FR2480051 A1 FR 2480051A1
Authority
FR
France
Prior art keywords
current
generator
transistor
resistor
zener diode
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.)
Granted
Application number
FR8007435A
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English (en)
French (fr)
Other versions
FR2480051B1 (https=
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.)
ALE International SAS
Original Assignee
La Telephone Industrielle et Commerciale Telic Alcatel SA
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 La Telephone Industrielle et Commerciale Telic Alcatel SA filed Critical La Telephone Industrielle et Commerciale Telic Alcatel SA
Priority to FR8007435A priority Critical patent/FR2480051A1/fr
Publication of FR2480051A1 publication Critical patent/FR2480051A1/fr
Application granted granted Critical
Publication of FR2480051B1 publication Critical patent/FR2480051B1/fr
Granted legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/30—Devices which can set up and transmit only one digit at a time
    • H04M1/50—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Devices For Supply Of Signal Current (AREA)
FR8007435A 1980-04-02 1980-04-02 Pushbutton keyboard for telephone - uses frequency generator supplied by pair of zener diodes and current source with current limiting circuit Granted FR2480051A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR8007435A FR2480051A1 (en) 1980-04-02 1980-04-02 Pushbutton keyboard for telephone - uses frequency generator supplied by pair of zener diodes and current source with current limiting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR8007435A FR2480051A1 (en) 1980-04-02 1980-04-02 Pushbutton keyboard for telephone - uses frequency generator supplied by pair of zener diodes and current source with current limiting circuit

Publications (2)

Publication Number Publication Date
FR2480051A1 true FR2480051A1 (en) 1981-10-09
FR2480051B1 FR2480051B1 (https=) 1988-03-11

Family

ID=9240459

Family Applications (1)

Application Number Title Priority Date Filing Date
FR8007435A Granted FR2480051A1 (en) 1980-04-02 1980-04-02 Pushbutton keyboard for telephone - uses frequency generator supplied by pair of zener diodes and current source with current limiting circuit

Country Status (1)

Country Link
FR (1) FR2480051A1 (https=)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2218410A1 (de) * 1972-04-15 1973-10-31 Tekade Felten & Guilleaume Steuerschaltung zum erzeugen einer zusaetzlichen schleifenunterbrechung fuer tastenwahl-fernsprechapparate
FR2279283A1 (fr) * 1974-07-19 1976-02-13 Telic Telephonie Indle Et Cale Poste a clavier
US4196318A (en) * 1978-09-29 1980-04-01 Bell Telephone Laboratories, Incorporated Electronically-switched multifrequency generator for providing tone signaling

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2218410A1 (de) * 1972-04-15 1973-10-31 Tekade Felten & Guilleaume Steuerschaltung zum erzeugen einer zusaetzlichen schleifenunterbrechung fuer tastenwahl-fernsprechapparate
FR2279283A1 (fr) * 1974-07-19 1976-02-13 Telic Telephonie Indle Et Cale Poste a clavier
US4196318A (en) * 1978-09-29 1980-04-01 Bell Telephone Laboratories, Incorporated Electronically-switched multifrequency generator for providing tone signaling

Also Published As

Publication number Publication date
FR2480051B1 (https=) 1988-03-11

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