CN2185490Y - Fraudulent use, wiretap and non-good setting prevention device for telephone - Google Patents
Fraudulent use, wiretap and non-good setting prevention device for telephone Download PDFInfo
- Publication number
- CN2185490Y CN2185490Y CN 93245322 CN93245322U CN2185490Y CN 2185490 Y CN2185490 Y CN 2185490Y CN 93245322 CN93245322 CN 93245322 CN 93245322 U CN93245322 U CN 93245322U CN 2185490 Y CN2185490 Y CN 2185490Y
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- CN
- China
- Prior art keywords
- triode
- resistance
- circuit
- switching circuit
- telephone
- 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.)
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Abstract
The utility model relates to a fraudulent use, wiretap and non-good setting prevention device for a telephone, which is composed of a feed line signal detection circuit, a local off-hook detection circuit, a switching circuit and an interference signal source. The fraudulent use, wiretap and non-good setting prevention device for a telephone has the advantages of low cost, and simple structure, and can efficiently prevent the fraudulent use of the telephone. The fraudulent use, wiretap and non-good setting prevention device for a telephone has the wiretap prevention function and the non-good setting prevention function.
Description
The utility model relates to the telephone set annex, and specifically a kind of phone is anti-to be usurped, anti-eavesdrop, anti-not hand-up device.
At present, still find no this device on the market.
The purpose of this utility model provides that a kind of telephone user phone anti-is usurped, anti-eavesdrop, anti-not hand-up device.
For achieving the above object, the utility model comprises feeder signals testing circuit, this machine off-hook detection circuit, switching circuit, interference signal source; The test side of feeder signals testing circuit is attempted by the telephone line line end, and the control end of its output and switching circuit joins; The output of this machine off-hook detection circuit and the control end of this switching circuit join, and its input and one are serially connected in the detection resistance in the telephone line and connect; Interference signal source is connected on the output circuit of switching circuit.
When on the telephone line usurp the phone off-hook time, signal of feeder signals circuit output is connected switching circuit, the feedback interference signal source powers up, the interference signal that interference signal source produces is admitted in the telephone line, makes to usurp phone and can not dial and converse.When this machine off-hook, be serially connected in the direct current of detection resistance by about 20-40mA in the telephone line, the pressure drop on it makes this machine off-hook detection circuit give switching circuit a pick-off signal, and interference signal source is not worked, but this machine normal talking.
The utlity model has simple in structure, cost is low, can prevent to usurp the characteristics of phone effectively, also has anti-eavesdrop, the anti-not function of on-hook simultaneously.
Fig. 1 is a circuit diagram of the present utility model.
Below in conjunction with accompanying drawing the utility model is described in detail.
The feeder signals testing circuit is by resistance R
1-R
5, transistor T
1, T
2Form.The resistance R of serial connection
1, R
2Two ends be connected across telephone line line end A as the test side of this circuit
1, A
2On, resistance R
3An end and resistance R
1, R
2Mid point join the other end and triode T
1Base stage connect triode T
1The emitter line terminals A that answers the call
2, triode T
1Collector electrode and triode T
2Base stage join triode T
2Emitter and the triode T in the switching circuit
3Base stage join.Here, triode T
1, T
2The emission output of feeder signals testing circuit very.Its operating state is that when phone was usurped in access in the telephone line, feeder voltage was about 48 volts, resistance R
2The voltage drop at two ends makes T
1Pipe is led, T
2Pipe ends.In being connected across telephone line usurp the phone off-hook time, the feeder voltage on the telephone wire is reduced to 7-9 volt, resistance R from 48 volts
2The pressure drop at two ends can not make T
1The pipe conducting, thus make T
2The pipe conducting.
This machine off-hook detection circuit is by testing circuit R
6, triode T
4Form, detect resistance R
6Be serially connected in the telephone wire loop triode T
4Collector electrode, emitter as the output of this circuit respectively with the triode T of switching circuit
3Base stage, emitter joins, when its operating state was this machine off-hook, feeder current was in resistance R
6The pressure drop of last generation is greater than 0.7 volt, T
4The pipe conducting; This machine is during off-hook, R
6On do not have pressure drop, T
4Pipe ends.
Switching circuit is by triode T
3, resistance R
7, diode D
2, D
3Light emitting transistor LED
2Form triode T
3Base stage, emitter joins as the output of this circuit, diode D
2, LED
2, diode D
3Forward connect again and resistance R
7Serial connection back and T
3Collector electrode join.T
3Emitter, D
2Positive pole respectively with telephone line line end A
2, A
1Connect.Chuan Jie diode D here
2, D
3, LED
2, resistance R
7With triode T
3Collector electrode, emitter constitute the output circuit of switching circuit.As triode T
3During conducting, output circuit has electric current to pass through, LED
2Luminous, and at LED
2, D
2Two ends produce 2.4 volts pressure drop.
The power end of interference signal source 1 is attempted by the LED of series connection
2And D
3Two ends, its signal output part is attempted by resistance R by a capacitor C
7Two ends.When switching circuit is connected, LED
2, D
3For providing working power, interference signal source makes its work.Interference signal source is by triode T
3Collector electrode, emitter, diode D
2, D
3, LED
2Deliver in the telephone line.
The utility model also comprises one by LED
1, diode D
1, resistance R
8Polarity indicating circuit and a piezo 2 that is connected on the interference signal source output terminal of constituting, and telephone line line end A
1, A
2, this machine terminals A
3, A
4A wherein
1Connect the positive polarity telephone wire, A
2Connect the negative polarity telephone wire, if connect instead, the polarity indicating circuit is luminous.
The course of work of the present utility model is:
When 1. leading to machine, the phone feeder voltage is 48 volts, T
1Conducting, T
2, T
3, T
4End LED
2Extinguish, the audio disturbances signal source is not worked, and piezo is stopped.
When 2. the user was led to machine, the phone feeder voltage was the 7-9 volt, and feeder current is 20-40mA, T
2, T
4Conducting, T
1, T
3End LED
2Extinguish, the audio disturbances signal source is not worked, and piezo is stopped.
3. in stolen, when eavesdropping,, the phone feeder voltage is the 7-9 volt, and the electric current that flows through telephone set is less than 20mA, T
2, T
3Conducting, T
1, T
4End LED
2Bright, interference signal source work, buzzing a short while.
If 4. talk-through not on-hook for a long time, the internal resistance of stored-program control exchange increases, and flows through the detection resistance R
6Electric current less than 20mA, T
2, T
3Conducting, T
1, T
4End LED
2Bright, interference signal source work, buzzing a short while.
Claims (5)
1, a kind of phone anti-usurp, anti-eavesdrop, anti-not hand-up device, it is characterized in that comprising: feeder signals testing circuit, this machine off-hook detection circuit, switching circuit, interference signal source; The test side of feeder signals testing circuit is attempted by the telephone line line end, and the control end of its output and switching circuit joins; The output of this machine off-hook detection circuit and the control end of this switching circuit join, and its input and one are serially connected in the detection resistance in the telephone line and connect; Interference signal source is connected on the output circuit of switching circuit.
2, device according to claim 1 is characterized in that the feeder signals testing circuit is by resistance R
1-R
5, transistor T
1, T
2Form.The resistance R of serial connection
1, R
2Two ends be connected across telephone line line end A as the test side
1, A
2On, resistance R
3An end and resistance R
1, R
2Mid point join the other end and triode T
1Base stage connect triode T
1The emitter line terminals A that answers the call
2, triode T
1Collector electrode and triode T
2Base stage join triode T
2Emitter and the triode T in the switching circuit
3Base stage join.
3, device according to claim 1 is characterized in that: this machine off-hook detection circuit is by testing circuit R
6, triode T
4Form, detect resistance R
6Be serially connected in the telephone wire loop triode T
4Collector electrode, emitter be attempted by resistance R as input
6Two ends, triode T
4Collector electrode, emitter as output respectively with the triode T of switching circuit
3Base stage, emitter joins.
4, device according to claim 1 is characterized in that: switching circuit is by triode T
3, resistance R
7, diode D
2, D
3LED
2Form.
5, device according to claim 1 is characterized in that, the power end of interference signal source is attempted by the LED of series connection
2With diode D
3Two ends, its output is attempted by resistance R by an electric capacity
7Two ends.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 93245322 CN2185490Y (en) | 1993-11-12 | 1993-11-12 | Fraudulent use, wiretap and non-good setting prevention device for telephone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 93245322 CN2185490Y (en) | 1993-11-12 | 1993-11-12 | Fraudulent use, wiretap and non-good setting prevention device for telephone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2185490Y true CN2185490Y (en) | 1994-12-14 |
Family
ID=33818300
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 93245322 Expired - Fee Related CN2185490Y (en) | 1993-11-12 | 1993-11-12 | Fraudulent use, wiretap and non-good setting prevention device for telephone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2185490Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004059954A1 (en) * | 2002-12-31 | 2004-07-15 | Minhai Liang | Method and means for preventing the mobile communicate device from interceptor by remote control |
-
1993
- 1993-11-12 CN CN 93245322 patent/CN2185490Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004059954A1 (en) * | 2002-12-31 | 2004-07-15 | Minhai Liang | Method and means for preventing the mobile communicate device from interceptor by remote control |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |