KR19980065138A - Public telephone theft prevention system - Google Patents

Abstract

The present invention relates to a public telephone fraud prevention system for preventing unauthorized use by connecting a general telephone or the like to a public telephone network in which a public telephone is connected and used. A switch including a plurality of public telephones 60 is connected to a subscriber. 10; A terminal control device 50 connected to the front end of the public telephone 60 on the telephone line; A plurality of channel units 30 connected one-to-one with the terminal control apparatus 50; A plurality of channel control units 23 for controlling the plurality of channel units 30; A central control unit 20 comprising a main control unit 21 for controlling the plurality of channel control units 23 and connected to the front end of the exchanger 10; Comprising a computer 40 for managing the central control unit 20 and a database of various data generated during the management of the central control device 20, by using a signal of the non-audible frequency band for public telephone management to affect the sound quality of the telephone call It does not affect the management of public telephones so that they can never be used illegally, and provides the effect of enabling high-speed data communication using telephone lines.

Description

Payphone anti-theft system

The present invention relates to a public telephone theft prevention system, and more particularly, to a public telephone theft prevention system for preventing the illegal use by connecting a general telephone or the like to a public telephone network to which the public telephone is connected and used.

In general, telephone lines are connected to trunk lines by exchanges within a single area, and connections to other areas are connected by trunk lines connecting exchange periods.

Thus, inter-subscriber communication in a single area is achieved by relaying of the corresponding exchange, and communication between subscribers in other areas is achieved by the trunk connection of the exchange period in which the caller is connected and the called party is connected.

On the other hand, the types of telephones include general telephones used by a specific person and public telephones that can be used by a certain number of users for a predetermined fee. The telephone lines to which such ordinary telephones and public telephones are connected have the same property.

In other words, in the case of a payphone, the billing system connected to the switchboard charges the fee by connecting the phone number of the phone and checking the usage history. The telephone charges are managed by checking and periodically collecting coin boxes of public telephones.

At this time, the usage fee of the public telephone is operated by the charging system of the public telephone itself, and the charge according to the call volume and the call area is made.

Therefore, there is a loophole that the telephone can be used indefinitely without paying the usage fee if the ordinary telephone is connected to the subscriber line to which the public telephone is connected and used illegally.

The public telephone theft prevention system for preventing the fraudulent use of such a public telephone has been developed a number of technologies, but there is a problem in that it is not properly used.

Patent Announcement No. 95-4950, a technology introduced in the toll-free call prevention system of public telephones, checks signals generated by whether coins or cards are inserted into coin-operated public telephones and card-type public telephones. It's a way to monitor the phone line.

However, this method has a problem in that a coin or a card is inserted only at the beginning of a telephone call attempt, and after that, when a general telephone is connected to a public telephone line, illegal use can not be prevented. Since audible frequency is used, there is a problem of impairing call sound quality or time delay due to signal confirmation.

In addition, the technique introduced in Patent Publication No. 96-3105, Method of Preventing Unauthorized Coupler Use of Payphone, does not use the payphone keypad to call the other party after the user off-hooks the receiver of the payphone and inputs the basic unit telephone fee. By using the telephone line coupler to transmit the telephone number of the other party using the DTMF (Dual Tone Multi-Frequency) signal generator, it is possible to prevent the long-term use of the long-distance phone using the basic unit rate. Checks whether the public phone's keypad is used or not, and compares the DTMF signal generated from the public phone keypad with the coupler. To prevent unauthorized use of pay phones .

However, this method blocks the public telephone connected to the telephone line, and there is a problem in that unauthorized use cannot be prevented when connecting other telephones.

The present invention is to solve the problems of the prior art as described above, by installing a fraudulent system using an inaudible frequency signal between the public telephone and the switchboard of the counterpart telephone connected by the charging system of the public telephone and the switchboard. It is an object of the present invention to provide a public telephone theft prevention system that prevents fraudulent use of public telephones by managing public telephone lines by comparing billings calculated according to area and call volume.

In order to achieve the above object, the present invention provides a public telephone fraud prevention system for preventing illegal use of public telephones, wherein the terminal control apparatus installed at the end of a plurality of telephone lines is connected to a public telephone. A line interface for controlling the connection of the; A line monitoring unit for monitoring a loop on / off signal and a charging signal of a telephone line; A transceiving unit which modulates and demodulates an inaudible frequency so as to transmit and receive a predetermined signal with the exchange side through the line interface; A memory for storing a password, a billing system, and the like unique to a payphone; And a terminal controller for controlling whether the public telephone is used illegally while transmitting and receiving a predetermined signal through the line interface and transmitting / receiving a predetermined signal through the line interface when the loop is on while monitoring the state of the line; The central control unit, which is connected to the plurality of terminal control units and installed on the exchange side, includes a line interface for controlling the connection between the exchange and the public telephone, and a line monitoring unit for monitoring the loop on / off signal and the charging signal of the telephone line. A transceiving unit for demodulating and demodulating to an inaudible frequency so as to transmit and receive a predetermined signal to and from a public telephone through the above line interface, and a line switching unit forcibly cutting off a telephone line when the public telephone is illegally used. When the loop is turned on while monitoring the state of the line through the line monitoring unit, the exchange unit transmits and receives a predetermined signal through the line interface with the transceiver to check whether the public telephone is illegally used. Control to cut off the line A channel unit connected one-to-one with the terminal control apparatus including; A channel controller connected to a plurality of the channel units; Provided is a public telephone theft prevention system characterized in that it comprises a plurality of the channel control unit is connected to include a main control unit for controlling all the channel unit.

1 is a block diagram showing the configuration of a terminal control device in a public telephone theft prevention system according to the present invention;

Figure 2 is a block diagram showing the configuration of the channel portion of the central control unit in the public telephone theft prevention system according to the present invention,

3 is a block diagram showing the configuration of a central control apparatus in the public telephone theft prevention system according to the present invention;

4 is a block diagram showing the overall configuration of a public telephone theft prevention system according to the present invention.

Explanation of symbols on the main parts of the drawings

10: exchanger 20: central control unit

30: channel portion 40: computer

50: terminal control device 60: public telephone

The configuration and operation of the public telephone theft prevention system according to the present invention will be described in detail through an embodiment of the present invention.

1 is a block diagram illustrating a configuration of a terminal control apparatus in a public telephone theft prevention system according to the present invention, and FIG. 2 illustrates a configuration of a channel unit of the central control apparatus in the public telephone theft prevention system according to the present invention. It is a block diagram. 3 is a block diagram showing the configuration of a central control apparatus in the public telephone theft prevention system according to the present invention, and FIG. 4 is a block diagram showing the configuration of the public telephone theft prevention system according to the present invention.

The overall configuration of the public telephone theft prevention system according to the present invention is as shown in Fig. 4, comprising: a switch 10 to which a subscriber including a plurality of public telephones 60 is connected; A terminal control device 50 connected to the front end of the public telephone 60 on the telephone line; A plurality of channel units 30 connected one-to-one with the terminal control apparatus 50; A plurality of channel control units 23 for controlling the plurality of channel units 30; A central control unit 20 comprising a main control unit 21 for controlling the plurality of channel control units 23 and connected to the front end of the exchanger 10; The central control device 20 is managed and consists of a computer 40 which manages a database of various data generated during management.

As shown in FIG. 1, the terminal control device 50 includes a line interface 54 for controlling a connection between the switch 10 and the public telephone 60; A line monitoring unit 53 for monitoring a loop on / off signal and a charging signal of a telephone line; A transceiving unit 52 which modulates and demodulates a non-audible frequency to transmit and receive a predetermined signal with the channel unit 30 on the side of the switch 10 through the line interface 54; A memory 55 for storing a password, a billing system, and the like unique to the public telephone 60; When the loop is turned on while monitoring the state of the line through the line monitoring unit 53, the public telephone while transmitting and receiving a predetermined signal with the channel unit 30 on the side of the exchanger 10 through the transceiver unit 52 and the line interface 54. It consists of a terminal control unit 51 for performing a control for checking whether or not the illegal use of (60).

As shown in FIG. 2, the channel unit 30 provides a line interface 34 for controlling the connection between the switch 10 and the public telephone 60, a loop on / off signal and a charging signal of a telephone line. Transmitting / receiving unit which modulates and demodulates at a subaudible frequency so as to transmit and receive a predetermined signal with the terminal control apparatus 50 on the public telephone 60 side through the line monitoring unit 33 to monitor and the line interface 34 described above. The switch 32 and the line switching unit 35 forcibly cutting off the telephone line when the public telephone 60 is illegally used, and when the loop is turned on while monitoring the state of the line through the line monitoring unit 33 10 and a predetermined signal are transmitted and received through the transmission and reception unit 32 and the line interface 34 to check whether the public telephone 60 is illegally used, and if the phone is illegally used, the public telephone through the above-mentioned line switching unit 35. Car 60 lines It consists of a controller 31 that performs control to.

Here, the line switching unit 35 is made of a relay for controlling the line by the control signal.

As shown in FIG. 3, the central control apparatus 20 includes a channel controller 23 in which a plurality of channel units 30 (8 channels in the present invention) are connected to the terminal control apparatus 50 one-to-one; The channel control unit 23 is composed of 16 main control unit 21 is connected to control.

On the other hand, the signal transmission and reception method between the terminal control device 50 and the channel control unit 30 is as follows.

The transmitting system transmits 28 kHz when it is '0' and 14 kHz when it is '1' by synchronizing the transmission data to TXD signal of the transmitting control unit, and transmits the frequency duration received by RXD of the control unit on the receiving side. '0' is transmitted at 28kHz and '1' at 14kHz.

Here, 14 and 28 kHz used for transmitting and receiving signals is a frequency band irrelevant to 0 to 4 kHz, which is a frequency band used for telephone lines, so that various signals can be transmitted and received even while the telephone is in use without affecting the sound quality of the telephone call. have.

For reference, the vocal range of a person is 300 to 3400 Hz in a wide range, and more narrowly, most voices are all included in the 300 to 1600 Hz band. It is as follows.

The public telephone anti-theft system according to the present invention configured as described above operates as follows.

The terminal control apparatus 50 connected to the front end of the public telephone 60, when the public telephone 60 is installed and used for the first time, modulates a predetermined start signal generated by the terminal controller 51 through the transceiver 52. The data is transmitted through the line interface 54, and the data including the password, the phone number, the billing system, and the like necessary for operating the public telephone 60 is received from the channel unit 30 and stored in the memory 55.

If the password, telephone number, billing system, etc. are changed while the public telephone 60 is in operation, the changed data is received to update the data in the memory 55 with new data.

Subsequently, in order to check whether the public telephone 60 is used, the random key index value transmitted from the channel unit 30 is received, and the corresponding key value of the public telephone 60 is found in the key table and transmitted. If the charging pulse is received from the public telephone from the telephone line, the telephone line is kept in a connected state. If the charging pulse is not received, the line monitoring unit 53 checks the loop-off of the telephone line. Returning to the on standby state, if the loop is on, the check pulse reception state is repeatedly performed.

Then, the channel unit 30 is initialized once the power is applied, and when the loop is turned on to use the public telephone 60, the control unit 31 lines the start signal transmitted from the terminal control device 50 described above. It receives through the interface 34 and the transceiver 32.

The transceiver 32 modulates a signal input at a frequency of 14 kHz or 28 kHz and modulates a digital signal of '0' or '1' to the controller 31.

At this time, if the payphone 60 is installed and used for the first time and a start signal is received from the terminal control device 50 on the payphone 60 side, the data necessary for managing the payphone, namely, password, telephone number, billing Send data including schemes.

In addition, if the password, telephone number, billing system, etc. for public telephone management is changed, the changed value is transmitted.

The data thus transmitted is stored in the memory 55 of the terminal control device 50 or the contents thereof are updated.

Therefore, when there is no change, it is not necessary to update the memory value of the terminal control device.

In order to prevent the illegal use of the public telephone 60 after transmitting a password, a telephone number, a billing system for managing the public telephone, the channel unit 30 transmits a random key index, and receives the terminal control apparatus ( 50 transmits 1 byte of a key value of a position corresponding to a key index from the previously received cipher to the channel unit 30.

If the key value received from the terminal control device 50 is the same as the key value of the position corresponding to the previously transmitted key index, the channel unit 30 keeps the telephone line in the loop on state for use of the public telephone 60. If the key value is different, the line is blocked through the line switching part 35 to prevent unauthorized use.

The key index is transmitted only once after the public telephone 60 is looped on, and the terminal control device 50 is generated at every charging pulse through its algorithm based on the received key index to transmit another key value. .

Similarly, the channel unit 30 may also compare the key values received from the terminal control apparatus 50 through a key index generation algorithm such as the terminal control apparatus 50 based on the transmitted key index.

The central control unit 20 manages 16 channel control units 23 connected to eight channel units 30 to manage telephone lines between the switch 10 and the public telephone 60 through the main control unit 21. .

Accordingly, the channel control unit 23 and the main control unit 21 establish a telephone line between the public telephone 60 and the switch 10 connected to the terminal control apparatus 50 connected one-to-one to the channel unit 30. To do.

On the other hand, the public telephone theft prevention system according to the present invention is a system for preventing the illegal use of the public telephone, but the system uses the frequency band of 14kHz to 28kHz band, which is an inaudible frequency band for management, It can be used for other data communication purposes.

Here, in general, the telephone line uses a frequency of 0 ~ 4kHz band, the other frequency band acts as noise, so the switch and each telephone is connected to the band pass filter of 0 ~ 4kHz band to remove noise .

Therefore, in order to enable data communication in other frequency bands using the public telephone anti-theft prevention system according to the present invention, a band pass filter must be connected and operated to allow a frequency of 14 to 28 kHz to pass through the exchange.

In this way, the voice call and the high-speed data communication can be simultaneously processed using a single line, thereby improving the use efficiency of the telephone line.

The public telephone theft prevention system according to the present invention made as described above manages a public telephone so that it can never be used fraudulently without affecting the sound quality of a telephone call by using a signal of an inaudible frequency band for public telephone management. In addition, it provides an effect that enables high-speed data communication using a telephone line.

Claims (3)

A public telephone theft prevention system for preventing public telephone fraud, Terminal control device 50 is installed at the end of a plurality of telephone lines connected to the public telephone 60 is A line interface 54 for controlling the connection between the exchange 10 and the public telephone 60; A line monitoring unit 53 for monitoring a loop on / off signal and a charging signal of a telephone line; A handset frequency converter 52 that modulates and demodulates an inaudible frequency so as to transmit and receive a predetermined signal with the channel unit 30 on the side of the switch 10 through the line interface 54; A memory 55 for storing a password, a billing system, and the like unique to the public telephone 60; When the loop is turned on while monitoring the state of the line through the line monitoring unit 53, the channel unit 30 on the exchanger 10 side transmits and receives a predetermined signal through the transmission and reception unit 52 and the line interface 54. It includes a terminal control unit 51 for performing a control for checking whether or not the telephone 60 is used illegally; The central control device 20 connected to the plurality of terminal control devices 50 and installed at the switchboard 10 has a line interface 34 for controlling the connection between the switchboard 10 and the public telephone 60. The line control unit 33 monitors the loop on / off signal and the charging signal of the telephone line, and the terminal control device 50 on the public telephone 60 side via the line interface 34 to the predetermined signal. Transmitting and receiving unit 32 for demodulating and demodulating to an inaudible frequency so as to transmit and receive, a line switching unit 35 for forcibly blocking a telephone line when the public telephone 60 is used illegally, and a line monitoring unit ( If the loop is turned on while monitoring the state of the line through 33), the exchange 10 and the predetermined signal are transmitted and received through the transceiver 32 and the line interface 34 to confirm whether the public telephone 60 is illegally used. And the channel unit 30 connected one-to-one with the terminal control apparatus, including a control unit 31 which controls to cut off the line on the payphone 60 side through the line switching unit 35 if it is used illegally. )Wow; A channel controller 23 to which a plurality of the channel units 30 are connected; Public channel theft prevention system characterized in that it comprises a main control unit 21 is connected to a plurality of one channel control unit 23 to control all the channel unit (30). 2. The public telephone theft prevention system according to claim 1, wherein the inaudible frequency band used for transmitting and receiving signals between the terminal control device and the channel section is 14 to 28 kHz. 2. The public telephone theft prevention system according to claim 1, wherein data communication can be performed using an inaudible frequency band used for signal transmission and reception between the terminal control apparatus (50) and the channel unit.