JPH01277047A - Public telephone set - Google Patents

Abstract

PURPOSE:To perform the walk back of a call issuing position without being found by a caller by providing a circuit to send a recognizable proper number automatically to a line when receiving a specific tone. CONSTITUTION:When a callee responds to call issuing from a public telephone set 1 and a speech content is recognized as a malicious call, the specific tone is sent to a subscriber line 2A by depressing an operating button 11A in a specific tone generator 11. A detection circuit 6 in the adaptor circuit 5 of the telephone set 1 detects the specific tone and sends it to a control part 7. The control part 7 transmits the telephone number of the telephone set 1 to a sending part 8, and operates switching contacts 9A and 9B. When the contact 9A is operated, the connection line of an exchange station 3A and the telephone set 1 is withdrawn to a sending part 8 side, and the telephone number is depressed and sent from the sending part 8 by a button dial signal. When sending is completed, the sending part 8 reports the fact to the control part 7, then, the contacts 9A and 9B are recovered. A callee side records the dial signal from a central office 2B on a recording part 12, and recognizes a calling telephone number.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit for a public telephone. INDUSTRIAL APPLICATION This invention is utilized for the reverse detection apparatus of a telephone line.

〔overview〕

The present invention provides public telephones with a circuit that automatically sends a unique number that can be identified to the line when a special tone is received, so that when a person wants to know the location of a public telephone in the case of a crime, etc., the special tone can be used. The sending device and the device for recording the number are connected to the receiving side, etc., so that the source can be immediately detected.

[Conventional technology]

Conventional public telephones are assigned a unique telephone number. This telephone number is managed by the switching office that houses the public telephone, and by knowing this telephone number, the location of the public telephone can be known.

[Problem that the invention seeks to solve]

However, public telephones do not have a function to transmit the assigned telephone number as information to the outside. Furthermore, public telephones are often used to make malicious calls such as threatening calls.

In order to trace this malicious call, it is necessary to trace the call back to the calling party from the exchange where the called party is accommodated, collect data at the exchange, and conduct a follow-up investigation. Even in exchanges that use electronic exchanges, it takes time to conduct a follow-up investigation, and in most cases it is extremely difficult to locate the source of a malicious call with just one call. In addition, in the telephone network in Japan, the types of exchange equipment are step-by-step type, crossbar type,
There are a variety of electronic exchange types, and there are exchanges that cannot collect data, and there are also cases where reverse detection is impossible due to the signaling system between exchanges.

SUMMARY OF THE INVENTION An object of the present invention is to provide a public telephone that can detect the location of a call without being noticed by the caller by a simple operation on the called party's side.

[Means for solving problems]

The present invention provides, in a public telephone set connected to a public telephone network via a subscriber line, a memory for storing a unique number that can be identified within the telephone network, and a detection system for detecting a special tone arriving at the subscriber line. The present invention is characterized by comprising a circuit, and circuit means for reading out a number from a memory in accordance with the detection output of the detection circuit and transmitting it as a code to a subscriber line.

[Effect]

When a public telephone is used for a crime, etc., and you want to know the location of the telephone, a device that sends the above-mentioned special tone to the line of the called party and a number sent in response to the telephone number are used to identify the receiver. Install the equipment to do so.

When a call comes from a public telephone, a special tone is generated and the telephone automatically sends a number that can be identified. This allows the user to immediately know the location of the public telephone by referring to the map used when the number was assigned.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

In this figure, a public telephone 1 equipped with a handset IA and a telephone circuit IB is connected to an exchange 3 via a subscriber line 2A.
A and 3B, trunk line 2B, and subscriber line 2C are connected to the public telephone network.

Here, the features of the present invention are that the present embodiment includes a memory 5 for storing a telephone number which is a unique number that can be identified within this telephone network, and a special tone for detecting a special tone arriving at the subscriber line 2A. A tone detection circuit 6, a control unit 7 as a circuit means for reading a telephone number from the memory 5 according to the detection output of the detection circuit 6, and transmitting the pushbutton dialing signal as a code to two subscriber lines; The present invention is provided with a sending section 8 and switching contacts 9A and 9B.

Each of these circuits and devices is mounted on the adapter 1c,
It is installed in the public telephone 1 in advance.

Reference numeral 10 denotes a termination section, which puts the telephone circuit IB into a silent state while the sending section 8 is sending out a push button dial signal, which is a symbol, to the subscriber line 2A.

The special tones that arrive at the two subscriber lines have frequencies in the voice frequency band (30 to 3400 Hz), and are transmitted with a short transmission width in the bass band with a low probability of being recognized as voice. This is sent by pressing the operation button IIA of the generator 11 provided at the terminal 4A of the called party's telephone 4 connected to the public telephone network.

The terminal 4B is also provided with a recording section 12 for recording a push button dial signal sent from the sending section 8 using the telephone number of the public telephone 1 as a code.

FIG. 2 is a sequence diagram of an example of use of the above embodiment. The operation of this embodiment will be explained using FIGS. 1 and 2.

According to sequence (2), the calling party makes a malicious call from the public telephone 1 to the called party via the telephone 4. According to the sequence (■), the called party responds and after confirming the content of the call, presses the operation button IIA of the generating means 11 at the time when it is recognized as a malicious call or immediately after the response.
A special tone is sent to subscriber line 2A via the public telephone network.
Send to. When the detection circuit 6 in the adapter circuit IC of the public telephone 1 detects a special tone, it sends its detection output to the control section 7. The control section 7 transmits the telephone number of the public telephone 1 held in the memory 5 to the sending section 8, and operates the switching contacts 9A and 9B. When the switching contact 9A operates, the connection line between the exchange 3A and the public telephone 1 is drawn into the sending section 8, and the sending section 8 sends out a telephone number by a push button dial signal. When the transmission of the push button dial signal is completed, the transmission section 8 reports this completion to the control section 7.

When the control section 7 receives this report, it returns the switching contacts 9A and 9B to their original state.

From sequence (2), the called party can recognize the telephone number of the public telephone used by the calling party by recording the push button dial signal transmitted from the central office line 2B in the recording unit 12.

The adapter circuit IC shown in FIG. 1 can be easily designed using existing technology.

Furthermore, although each device of the telephone 4 has been described as being connected to the terminal 4A, it can also be mounted on the casing of the telephone.

〔Effect of the invention〕

As explained above, according to the present invention, there is an effect that the called party can easily recognize the telephone number of the calling party using a public telephone.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 2 is a sequence diagram of an example of use of the above embodiment. ■...Public telephone, IA...Handset, IB...
Telephone circuit, IC...adapter circuit, 2A, 2C...
Subscriber line, 2B... Trunk line, 3A, 3B... Exchange, 4... Telephone, 4A... Terminal, 5... Memory, 6... Special tone detection circuit, 7. ...Control unit, 8
...Push button dial signal sending unit, 9A, 9B...
- Switching contact, lO... Terminal section, 11... Special tone generator, 12... Recording section.

Claims (1)

[Claims] 1. In a public telephone connected to a public telephone network via a subscriber line, a memory for storing a unique number that can be identified within the telephone network; A public telephone set comprising: a detection circuit for detecting a tone; and circuit means for reading the number from the memory according to the detection output of the detection circuit and transmitting it as a code to the subscriber line.