JPH0454754A - Cordless telephone set - Google Patents

Abstract

PURPOSE:To prevent transmission of noise to a telephone line based on an on-hook signal by muting the telephone line when a detected signal is a signal representing a speech head and interrupting the telephone line when the detected signal is a signal representing a main body part. CONSTITUTION:When an on-hook signal detection circuit 19 detects a speech head A of an on-hook signal demodulated by a reception circuit 18, the circuit 19 sends a detection signal to a control circuit 20. The circuit 20 sends a mute-on signal to a line mute circuit 13 to activate the circuit 13 thereby muting the output to a telephone line 11 from a hybrid circuit 14. When the circuit 19 detects a main body B in succession to the speech head A, the circuit 19 sends the detection signal to the circuit 20. The circuit 20 sends a mute-off signal to the circuit 13 based on the detection signal to inactivate the circuit 13 again.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cordless telephone comprising a connecting device connected to a telephone line and a mobile device connected to the connecting device via a wireless line.

(Prior Art) In a conventional cordless telephone, when a hook switch is turned on on the mobile device side after a call ends, an on-hook signal is transmitted to the connecting device side through a wireless line. When the connection device receives the on-hook signal, it turns on-hook the hook switch on the connection device side and disconnects the line.

By the way, assuming the baud rate is 1200 bps, the on-hook signal sent from the mobile device has a prefix of several bits A, followed by a
Main body part B of 20-odd bits (signal length is 20 IIlsec)
below. ). After receiving the prefix part A of several bits and the main part B of 20-odd bits, the connecting device determines that it is an on-hook signal from the mobile device, turns the hook switch on-hook, and disconnects the line. It turns out.

(Issues to be Solved by the Invention) In this way, conventional cordless telephones receive an on-hook signal from a mobile device, determine that the received signal is an on-hook signal, and then disconnect the line. If this on-hook signal leaks into the telephone line before the line is disconnected, the leaked signal is transmitted as noise to the other party's telephone after the call ends, causing a problem in that the other party feels uncomfortable.

The present invention has been made in view of the above circumstances, and its purpose is to transmit an on-hook signal to the connecting device when on-hook on the mobile device side, and then to enable the hook switch on the connecting device to actually go on-hook. By muting the connection between the connected device and the telephone line until
An object of the present invention is to provide a cordless telephone that prevents noise from being transmitted to a telephone line based on an on-hook signal.

(Means for Solving the Problems) In order to solve the above problems, the cordless telephone of the present invention distinguishes and detects the prefix portion of an on-hook signal sent from a mobile device and the main body portion that follows, and detects the Based on the on-hook signal detection circuit that sends the signal and the detection signal of this on-hook signal detection circuit, when the detection signal is a signal indicating the prefix part, the telephone line is muted, and the detection signal is a signal indicating the main body part. Sometimes, the connection device is provided with a line mute circuit that disconnects the telephone line and unmutes the telephone line when the on-hook signal detection circuit cannot detect a signal indicating the main body part.

(Operation) The on-hook signal detection circuit provided in the connection device distinguishes and detects the prefix part of the on-hook signal sent from the mobile device and the main part following it, and sends the detection signal to the mute circuit. The mute circuit mutes the telephone line based on this detection signal when the detection signal is a signal indicating a prefix. Thereafter, when the detection signal becomes a signal indicating the main body part, the telephone line is disconnected. In other words, by muting the connection between the connecting device and the telephone line after the on-hook signal from the mobile device is sent to the connecting device until the hook switch on the connecting device is turned on-hook, the connection between the connecting device and the telephone line is muted. Noise is prevented from being transmitted onto the telephone line.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an electrical block diagram of a connecting device 10 constituting the cordless telephone of the present invention, and FIG. 2 is an electrical block diagram of a mobile device 30 constituting the cordless telephone.

In Figure 1, telephone line 1 connects to the other party's terminal.
1 is a line mute circuit 1 via a hook switch 12
3, and is also connected to an incoming call detection circuit 15 that detects an incoming signal, and the output of the incoming call detection circuit 15 is led to a control circuit 20. Further, the line mute circuit 13 is connected to a hybrid circuit 14 that exchanges signals with the other party's terminal.
The output of 4 is led to a transmitting circuit 16.

In addition to the output of the hybrid circuit 14, the transmission circuit 16 also includes an output 20a of the control circuit 20 and a synthesizer 17.
The output of The transmitting circuit 16 modulates the audio signal sent from the other party's terminal and the data signal from the control circuit 20 into a 380 MHz band wireless signal, and
The signal is amplified to a required transmission power level and output to the antenna 22.

Further, an antenna 22 is connected to the receiving circuit 18, and the output of the synthesizer 17 is guided thereto. The receiving circuit 18 receives a 250 MHz band radio signal from the mobile device 30 and demodulates it into an audio signal and a data signal. The output 18a of the receiving circuit 18 that sends out audio signals is transmitted to the hybrid circuit 14.
The output 18b of the receiving circuit 18 that sends data signals is guided to the telephone line 11 via the control circuit 20.
guided by. Moreover, the output 18c of the receiving circuit 18 is
It is led to an on-hook signal detection circuit 19 that detects an on-hook signal from the mobile device 30 , and the output of the on-hook signal detection circuit 19 is led to a control circuit 20 .

Further, the output 20b of the control circuit 20 is output from the synthesizer 17.
guided by. The control circuit 20 controls the radio channel by controlling the synthesizer 17, sends a data signal to the transmitting circuit 16 as a modulation input, and identifies the data signal demodulated by the receiving circuit 18. It has the following functions. Further, the output 20c of the control circuit 20 that sends out a control signal based on the detection signal from the on-hook signal detection circuit 19 is led to the control terminal of the line mute circuit 13.
An output 20d of the control circuit 20 that sends out a control signal based on a detection signal from the hook switch 12 is configured to be led to a switching control terminal of the hook switch 12 via a line relay 21.

, the output of the transmitting circuit 32 and the input of the receiving circuit 330 are connected. Further, the output of the synthesizer 34 to which the control signal from the control circuit 35 is guided is guided to the receiving circuit 33 . The receiving circuit 33 receives 380 from the connecting device 10.
It receives a radio signal in the MHz band and demodulates it into an audio signal and a data signal. and,
One output 33a of the receiving circuit 33 is guided to the speaker 37 as an audio signal, and the other output 33b of the receiving circuit 33 is guided to the control circuit 35 as a data signal. Further, the output of the microphone 36 is guided to the transmitting circuit 32, and the output of the synthesizer 34 and the output of the control circuit 35 are also guided. The transmission circuit 32 modulates the audio signal from the microphone 36 and the data signal from the control circuit 35 into a 250 MHz band wireless signal, amplifies it to a required transmission power level, and sends it to the antenna 3. ing. Further, the control circuit 35 is configured to receive the output of a hook detection circuit 38 that detects the on/off state of a hook switch (not shown) of the mobile device 30.

Next, the operation of the cordless telephone having the above configuration will be explained with reference to the flowchart shown in FIG. 3 as appropriate.

When a communication path is established between the other party's terminal and this telephone via the telephone line 11, the hook switch 12 of the connection device 10 is placed in an off-hook state by the operation of the line relay 21 under control from the control circuit 20. It becomes. Further, in this state, the line mute circuit 13 is in an inactive state, and the hybrid circuit 14 is connected to the telephone line 11 via the hook switch 12.

In this state, the call between the two parties ends, and the user of the cordless telephone sets the hook switch of the mobile unit 30 (not shown).
When on-hook, this on-hook state is detected by the hook detection circuit 38, and the detection signal is sent to the control circuit 3.
given to 5. Based on the detection signal from the hook detection circuit 38, the control circuit 35 sends the on-hook signal shown in FIG. It is transmitted from the antenna 31.

In the connection device 10, the reception circuit 18 receives the wireless signal transmitted from the mobile device 30 via the antenna 22,
Here, it is demodulated to the original on-hook signal and sent to the control circuit 20.

On the other hand, the on-hook signal detection circuit 19 constantly performs sampling for the receiving circuit 18 to detect the prefix part A and the main part B of the on-hook signal (step Sl). Then, when the on-hook signal detection circuit engineer 9 detects the prefix part A of the on-hook signal demodulated by the receiving circuit 18 (step S2), it sends a detection signal indicating that the prefix part A has been detected to the control circuit 20. . Based on the detection signal from the on-hook signal detection circuit 19, the control circuit 20 sends a mute-on signal to the line mute circuit 13, puts the line mute circuit 13 into an operating state, and connects the telephone line 11 from the hybrid circuit 14. mute the output (step S3). Thereafter, when the on-hook signal detection circuit 19 detects the main body part B following the prefix part A of the on-hook signal (step S4), it sends a detection signal indicating that the main body part B has been detected to the control circuit No. 20. Based on the detection signal from the on-hook signal detection circuit 19, the control circuit 20 sends a mute-off signal to the line mute circuit 13, thereby rendering the line mute circuit 13 inactive again. At this time, the control circuit 20 receives the on-hook signal from the receiving circuit 18.
A control signal is sent to line relay 21, and line relay 2
1, the hook switch 12 which was in the off-hook state is brought into an on-hook state, and the connection between the telephone line 11 and the hybrid circuit 14 is cut off (step S5).

That is, since the line mute circuit 13 mutes the telephone line 11 for about 20 Ilsec from when the prefix A of the on-hook signal is detected until the telephone line is disconnected, the receiving circuit 18 to the control circuit 20 Even if the on-hook signal sent to the terminal leaks to the Hamplid circuit 14 side, the main body part B of the on-hook signal will not be sent to the other party's terminal as noise.

Note that if the main body part B of the on-hook signal is not detected in step S4, do not disconnect the line (keep the communication path secured, return to step S1, and detect the prefix part A of the on-hook signal). This prevents unexpected disconnection of the telephone line due to malfunction.

(Effects of the Invention) The cordless telephone of the present invention mutes the telephone line based on the detection signal of the on-hook signal detection circuit provided on the connection device side, and mutes the telephone line when the detection signal is a signal indicating a prefix. The telephone line is disconnected when the on-hook signal indicates the main unit, so even if this on-hook signal leaks to the telephone line before the line is disconnected, this on-hook signal will be sent to the other party's phone after the call ends. Since the leaked signal is not transmitted as noise, the other party will not feel uncomfortable.

[Brief explanation of drawings]

Fig. 1 is an electrical block diagram of a connecting device constituting the cordless telephone of the present invention, Fig. 2 is an electrical block diagram of a mobile device constituting the cordless telephone, and Fig. 3 explains the operation of the cordless telephone. Flowchart for, No. 4
The figure is a configuration diagram of an on-hook signal. 10... Connection device 11... Telephone line 12... Hook switch 13... Line mute circuit 14... Hybrid circuit 15... Incoming call detection circuit 16... Transmission circuit 17... Synthesizer 18 ... Receiving circuit 19 ... On-hook signal detection circuit 20 ... Control circuit 21 ... Line relay 22 ... Antenna 30 ... Mobile device 31 ... Antenna 32 ... Transmission circuit 33 ...・Reception circuit 34...Synthesizer 35...Control circuit 36...Microphone 37...Speaker 38...Hook detection circuit Patent applicant Sekisui Chemical Co., Ltd. Representative Hiroshi 1) Kaoru Dai 2 ti 3 figure

Claims (1)

[Scope of Claims] 1) In a cordless telephone comprising a connection device connected to a telephone line and a mobile device connected to the connection device via a wireless line, the connection device receives a message sent from the mobile device to the connection device. an on-hook signal detection circuit that distinguishes and detects the prefix part of the coming on-hook signal and the main body part that follows and sends out a detection signal; and a signal in which the detection signal indicates the prefix part based on the detection signal of this on-hook signal detection circuit. , the telephone line is muted, and when the detection signal is a signal indicating the body part, the telephone line is disconnected, and when the on-hook signal detection circuit cannot detect a signal indicating the body part, the telephone line is muted. A cordless telephone characterized by being provided with a line mute circuit for canceling the line mute circuit.