FR2434529A1 - Electronic circuit connected in telephone line - prevents fraudulent use of line by monitoring line current and shorting line in preset circumstances - Google Patents
Electronic circuit connected in telephone line - prevents fraudulent use of line by monitoring line current and shorting line in preset circumstancesInfo
- Publication number
- FR2434529A1 FR2434529A1 FR7824258A FR7824258A FR2434529A1 FR 2434529 A1 FR2434529 A1 FR 2434529A1 FR 7824258 A FR7824258 A FR 7824258A FR 7824258 A FR7824258 A FR 7824258A FR 2434529 A1 FR2434529 A1 FR 2434529A1
- Authority
- FR
- France
- Prior art keywords
- line
- telephone
- electronic circuit
- circumstances
- preset
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M17/00—Prepayment of wireline communication systems, wireless communication systems or telephone systems
- H04M17/02—Coin-freed or check-freed systems, e.g. mobile- or card-operated phones, public telephones or booths
- H04M17/023—Circuit arrangements
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Computer Security & Cryptography (AREA)
- Signal Processing (AREA)
- Prepayment Telephone Systems (AREA)
Abstract
A telephone set (2) is coupled through two conductors (11, 10) through payment recorded devices (12, 20, 21) to a central station. A fraud prevention electronic circuit (1) is connected in the second line, at earth potential, between the set (1) and recorded device (21) while the first line, at for example -48v, includes a line switch (13). When a call is connected, line current flow, through a diode (CR1) in the second line the voltage drop across which inhibits a transistor detection circuit (DI) in the electronic circuit (1). The detection circuit maintains non-conductive through a Darlington amplifier (AP), a thyristor (Th1) connected across the conductors. An attempt to use the telephone fraudulently by earthing its microphone terminal (6, 7, 8) turns off the diode (CR1) which triggers the thyristor (Th1) to short-circuit the telephone time.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR7824258A FR2434529A1 (en) | 1978-08-21 | 1978-08-21 | Electronic circuit connected in telephone line - prevents fraudulent use of line by monitoring line current and shorting line in preset circumstances |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR7824258A FR2434529A1 (en) | 1978-08-21 | 1978-08-21 | Electronic circuit connected in telephone line - prevents fraudulent use of line by monitoring line current and shorting line in preset circumstances |
Publications (2)
Publication Number | Publication Date |
---|---|
FR2434529A1 true FR2434529A1 (en) | 1980-03-21 |
FR2434529B3 FR2434529B3 (en) | 1981-05-22 |
Family
ID=9211965
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR7824258A Granted FR2434529A1 (en) | 1978-08-21 | 1978-08-21 | Electronic circuit connected in telephone line - prevents fraudulent use of line by monitoring line current and shorting line in preset circumstances |
Country Status (1)
Country | Link |
---|---|
FR (1) | FR2434529A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0417979A2 (en) * | 1989-09-15 | 1991-03-20 | Mars Incorporated | Method and apparatus for preventing pay telephone fraud and reducing handset vandalism |
EP0727898A1 (en) * | 1995-02-10 | 1996-08-21 | Landis & Gyr Technology Innovation AG | Telephone station |
US5864618A (en) * | 1995-02-10 | 1999-01-26 | Electrowatt Technology Innovation Ag | Telephone set having an anti-fraud arrangement which prevents any fraudulent attempt to the telephone |
NL1006183C2 (en) * | 1996-05-31 | 1999-07-13 | Lucent Technologies Inc | Method and device for preventing pen fraud in coin telephones using voltage reversal pulses to measure the costs. |
-
1978
- 1978-08-21 FR FR7824258A patent/FR2434529A1/en active Granted
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0417979A2 (en) * | 1989-09-15 | 1991-03-20 | Mars Incorporated | Method and apparatus for preventing pay telephone fraud and reducing handset vandalism |
EP0417979A3 (en) * | 1989-09-15 | 1992-05-13 | Mars Incorporated | Method and apparatus for preventing pay telephone fraud and reducing handset vandalism |
EP0727898A1 (en) * | 1995-02-10 | 1996-08-21 | Landis & Gyr Technology Innovation AG | Telephone station |
US5864618A (en) * | 1995-02-10 | 1999-01-26 | Electrowatt Technology Innovation Ag | Telephone set having an anti-fraud arrangement which prevents any fraudulent attempt to the telephone |
NL1006183C2 (en) * | 1996-05-31 | 1999-07-13 | Lucent Technologies Inc | Method and device for preventing pen fraud in coin telephones using voltage reversal pulses to measure the costs. |
Also Published As
Publication number | Publication date |
---|---|
FR2434529B3 (en) | 1981-05-22 |
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