JP4249687B2 - Telephone with outgoing call control function - Google Patents

Description

  The present invention relates to a telephone with a call restriction function, and in particular, even if a call restriction telephone number by DTMF (Dial Tone Multi Frequency) from a DTMF generator outside the telephone is input to a handset transmitter, The present invention relates to a telephone with a call restriction function capable of preventing transmission to a telephone line.

  The DTMF signal assigns four low group frequencies and three high group frequencies in the voice band to 12 types of push buttons (0-9, *, 0, #) installed on the telephone, and the low group and high group This is an audio band analog signal that is mixed. Therefore, instead of inputting the telephone number with the keyboard, the telephone number can be transmitted via a handset transmitter from a DTMF generator commercially available as a remote commander or the like.

  On the other hand, there are cases where long-distance or international calls are made due to carelessness of the user or mischief of the child, and high call charges may be charged. The function can be set.

  However, if the remote commander is used, the outgoing call restriction function does not work, so the registered name holder of the telephone must pay the expensive long-distance telephone call sent by a malicious third party.

  Therefore, in the telephone disclosed in Patent Document 1, from the start of line connection by off-hook to the completion of line connection with the other party, the transmitter signal is muted to prevent transmission of the DTMF signal. Specifically, the telephone is off-hooked to form a line loop, and the line polarity is reversed. At the same time as the polarity reversal, the transmitter signal is muted. Since the polarity is reversed again when the phone is connected to the other party, the mute is canceled at this timing.

Japanese Patent Laid-Open No. 6-244928 (FIG. 2, paragraph 0027)

  However, in Patent Document 1, since the polarity inversion detection circuit must be provided, the entire apparatus becomes complicated and there is a problem of cost.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a telephone that mutes a DTMF signal from a handset transmitter without using a polarity reversal detection circuit and prevents an outgoing regulation escape from the outside of the telephone.

  In order to solve the above-mentioned problems, the telephone with a call restriction function according to the present invention employs the following characteristic configuration.

(1) a dial tone detection circuit for detecting a dial tone and the other party's ring tone from the exchange;
A control unit that controls dialing
From the time when the dial tone detection circuit detects the dial tone from the exchange until the other party's ringing tone is detected,
The control unit is a telephone with a call restriction function that mutes the output of the transmitter and restricts the call to a call number from a dial keypad.

(2) a transmitter for inputting an analog DTMF signal from a DTMF signal generator outside the telephone;
The telephone with an outgoing call restriction function according to (1), wherein the control unit converts a outgoing call number input from a dial keypad into an analog DTMF signal.

  (3) The dial tone detection circuit outputs a detection signal that maintains a certain logic level from when the dial tone detection circuit detects a dial tone from the exchange until it detects the other party's ringing tone. (1) or (2) of the telephone with a call restriction function input to

  (4) The telephone with a call regulation function according to (3), wherein the control unit mutes a signal output from the transmitter based on the detection signal.

  (5) The telephone with a call restriction function according to (1) or (2), wherein the call restriction is performed when the first digit of the telephone number is a specific number.

  (6) The telephone with a call restriction function according to (1) or (2), wherein the call restriction is performed when the number of digits of the telephone number exceeds a predetermined number.

  (7) A dial tone detection circuit for detecting a dial tone and a partner's ringing tone from the exchange, and a control means for restricting dialing, and the other party from when the dial tone detection circuit detects a dial tone from the exchange A telephone with a call restriction function, wherein the control means performs call restriction by invalidating the input from the transmitter for a predetermined time until the response.

  According to the present invention, a DTMF from a handset transmitter is detected by detecting a dial tone (a sound indicating that a telephone number from a telephone is waiting) without using a polarity reversal detection circuit. The signal can be muted.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a telephone with a call restriction function according to an embodiment of the present invention.

  The telephone 2 with a call restriction function is connected to the exchange 1 via a telephone line. The telephone set 2 with a call restriction function includes a hook switch 3, a speech IC (voice transmitting / receiving unit) 5 connected to the hook switch 3, and a transmitter 7 and a receiver 8 connected to the speech IC 5. Further, a CPU (dial call function unit) 6 that converts a call telephone number input from a dial keypad (push button) 9 into a DTMF signal is connected to the speech IC 5. Here, the CPU 6 also has a transmission restriction function. For example, when the first digit of a telephone number is zero, the call restriction may be performed. In addition, for example, when the number of digits of a telephone number exceeds a predetermined number, outgoing calls may be restricted.

  The telephone 2 with a call restriction function has a dial tone detection circuit 4 connected to the hook switch 3 and detects a dial tone (signal sound waiting for a telephone number from the telephone) and the other party's ringing tone from the exchange 1, The detection result is output to the CPU 6. The detection signal is a signal that maintains a certain logic level (“1” if positive logic) from dial tone detection to partner party ringing tone detection. The CPU 6 mutes the output of the transmitter 7 based on the detection signal.

Next, the operation of the telephone set 2 with a call restriction function will be described.
The transmitter 7 outputs a call voice signal to the speech IC 5 during a call, but the DTMF signal (telephone number) from the DTMF signal generator 10 is detected from the detection of the dial tone at the off-hook to the detection of the other party's ringing tone. Is input to the transmitter 7 and output to the speech IC 5.

  When the telephone set 2 with a call restriction function calls the exchange 1 and receives the dial tone of the exchange 1, the detection signal holding a certain logical value is input to the CPU 6 by the dial tone detection circuit 4, and the CPU 6 receives the detection signal. Based on the above, the DTMF signal from the DTMF signal generator 10 is muted.

  When the other party's telephone number is input from the dial keypad 9 during mute, if the other party's telephone number is subject to outgoing restriction, the CPU 6 restricts outgoing calls. Call a phone number.

  In this way, in this embodiment, when the telephone is off-hooked (when the line is captured), the exchange sends a dial tone with a signal sound that accepts the dial signal from the telephone to the telephone, so the telephone detects the dial tone from the exchange. If this happens, the transmission signal is muted, and transmission when a DTMF signal generator that enters from the transmitter is used is prohibited.

  The configuration and operation of the preferred embodiment of the present invention have been described in detail above. However, these embodiments are merely examples of the present invention, and are not intended to limit the present invention in any way, and various modifications and changes can be made according to specific applications without departing from the gist of the present invention. .

It is a block diagram of a telephone with an outgoing call restriction function.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Switch 2 Telephone with a call origination control function 3 Hook switch 4 Dial tone detection circuit 5 Speech IC
6 CPU (Dial transmission function)
7 Transmitter 8 Receiver 9 Dial keypad 10 DTMF signal generator

Claims (7)

A dial tone detection circuit for detecting a dial tone and the other party's ring tone from the exchange;
A control unit that controls dialing
From the time when the dial tone detection circuit detects the dial tone from the exchange until the other party's ringing tone is detected,
The telephone with an outgoing call restriction function, wherein the control unit mutes the output of the transmitter and restricts outgoing calls to outgoing numbers from a dial keypad. A transmitter for inputting an analog DTMF signal from a DTMF signal generator external to the telephone;
2. The telephone with a call restriction function according to claim 1, wherein the control unit converts a call number input from a dial keypad into an analog DTMF signal.   The dial tone detection circuit inputs a detection signal holding a certain logic level to the CPU from when the dial tone detection circuit detects a dial tone from the exchange until it detects the other party's ringing tone. The telephone with an outgoing call restriction function according to claim 1 or 2.   The telephone with a call restriction function according to claim 3, wherein the control unit mutes a signal output from the transmitter based on the detection signal.   3. The telephone with a call restriction function according to claim 1, wherein the call restriction is performed when a first digit of a telephone number is a specific number.   The telephone with a call restriction function according to claim 1 or 2, wherein the call restriction is performed when the number of digits of a telephone number exceeds a predetermined number.   A dial tone detection circuit for detecting a dial tone from the exchange and the other party's ringing tone and a control means for restricting dial transmission, and the other party responds when the dial tone detection circuit detects a dial tone from the exchange. A telephone with a call restriction function, wherein the control means performs a call restriction by invalidating an input from a transmitter for a predetermined time until the time.

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