JP3453740B2 - Intercom equipment - Google Patents

Description

Detailed Description of the Invention

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device using a melody as a ringing tone.

[0002]

2. Description of the Related Art Some conventional intercom systems are provided with a ringing circuit for producing two attenuated sounds having different frequencies as a ringing sound, a so-called ping-pong ringing circuit.
The ping-pong calling circuit changes the oscillating frequency of one oscillating circuit to generate a calling sound, and a voice signal from the ping-pong calling circuit is amplified and output by an amplifier. In this case, in order to reduce power consumption, the power supply voltage is supplied to the amplifier only when the audio signal is generated.

FIG. 3 is a block diagram showing such a conventional intercom system.

The intercom subunit 1 is provided with a push button switch (not shown), and a ringing tone is generated by turning the push button switch on and off. That is, when the visitor pushes the push button switch of the intercom subunit 1, the button state detection circuit 2 detects the ON state of the button and outputs a detection signal to the frequency variable oscillator 3 and the power supply circuit 4. When the detection signal is input, the power supply circuit 4 supplies the power supply voltage to the amplifier 6.

The frequency variable oscillator 3 oscillates at a predetermined frequency when a detection signal is input, and gives an oscillation output to the modulation circuit 5. The modulation circuit 5 amplitude-modulates the oscillation output with an attenuation wave.
As a result, the amplitude of the oscillation output gradually decreases. After the output of the modulation circuit 5 is amplified by the amplifier 6, the speaker 7 provided in the main body of the master unit and the doorphone slave unit (not shown)
Is output from. As a result, a sound of a pin that decays and disappears after a predetermined time has passed from the ON operation of the push button switch is heard from the master unit and the slave unit.

The visitor releases his hand after a predetermined time has elapsed from the pressing operation of the push button switch of the intercom subunit 2. Then, the button state detection circuit 2 detects an off operation of the push button switch and outputs a detection signal to the frequency variable oscillator 3 and the timer 8. The variable frequency oscillator 3 changes the oscillation frequency when the detection signal is input. The oscillation output is modulated by the modulation circuit 5, the attenuated sound is amplified by the amplifier 6, and then the sound is output from the speaker 7. That is, a popping sound is generated, which decays and disappears after a predetermined time from the turn-off operation of the push button switch by the visitor.

On the other hand, the timer 8 obtains the time from the input of the detection signal based on the off operation of the push button switch.
The timer 8 is composed of a time constant circuit composed of a resistor and a capacitor, and when a predetermined time has elapsed from the input of the detection signal, it generates a stop signal and outputs it to the power supply circuit 4. The stop signal causes the power supply circuit 4 to stop the supply of the power supply voltage to the amplifier 6. In this way, after a lapse of a predetermined time from the operation of turning off the push button switch, the call is terminated and the standby state is restored to reduce the power consumption.

By the way, conventionally, using a melody IC,
A calling circuit that generates a melody as a calling sound may be adopted. Also in this case, the melody is started to be output by the turn-on operation of the push button by the visitor. If a low-priced 3-terminal melody IC having three terminals of a power supply terminal, a GND terminal, and a melody output terminal is adopted as the melody IC, a busy signal indicating that the melody is being output is not output from the melody IC. , A timer circuit must be used to return to the standby state. That is, in order to end the calling state, as in the ping-pong calling circuit, a timer is activated by an off operation of a push button by an alien, and the amplifier is turned off after the melody ends.

However, since the melody is output for a relatively long time of 20 to 30 seconds, the stop signal can be accurately output immediately after the end of the melody because of the accuracy of the timer (hereinafter referred to as CR timer) composed of the time constant circuit. It is difficult to generate. Further, in consideration of variations in the melody IC, the control using the CR timer cannot reliably return to the standby state immediately after the melody ends. Sometimes it returns to the state, also,
On the other hand, even after the melody ends, the standby state may not be restored for a while, and power consumption may increase.

Therefore, a method of terminating the calling state is adopted by using a multi-pin type melody IC provided with a terminal for outputting a busy signal during the output of the melody. That is,
In this case, the supply of the power supply voltage to the amplifier is controlled by the busy signal without using the CR timer.

However, the multi-pin type melody IC is expensive and has a drawback that it occupies a large area on the substrate because it is a multi-pin type.

[0012]

As described above, in the above-described conventional intercom apparatus, if the inexpensive three-terminal type melody IC is adopted, the return from the calling state to the standby state is not accurately performed, and therefore it is expensive. There is a problem that a multi-pin type melody IC, which has a large board occupying area, must be used.

The present invention has been made in view of the above problems, and provides a communication device which can surely control the return from the calling state to the standby state regardless of which calling circuit is adopted. The purpose is to

[Constitution of Invention]

A calling device according to the present invention comprises a calling detection circuit for detecting calling information from a user and outputting a calling detection signal in a standby state,
A ringing tone generation circuit that shifts from the standby state to the ringing state by the ringing detection signal and outputs a ringing tone, a ringing tone detection circuit that detects that the ringing tone is being output, and a ringing tone detection circuit When it is detected that the ringing tone is being output , the ringing tone generating circuit is continuously operated to output the ringing tone.
The detection circuit detects that the ringing tone has been output.
And a call activation control circuit for returning from the calling state to the standby state by being issued .

[0015]

In the present invention, the ringing tone generation circuit generates the ringing tone by detecting the ringing information from the user . The ringing tone detection circuit detects that a ringing tone is generated. This ringtone test
The output circuit detects that the ringing tone is being output.
If the ring tone is generated, continue to operate the ringing tone generation circuit,
The ringing tone detection circuit has finished outputting the ringing tone.
Is detected, the call activation control circuit
Return from the calling state to the standby state. As a result, the ringing tone is output to the end, and after the ringing tone ends, the standby state is surely restored.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of a communication device according to the present invention.

An intercom slave, not shown, is connected between the intercom terminal 11 and the reference potential terminal 12. The power supply voltage Vcc is supplied to the power supply terminal 13. Doorphone terminal 11
Is connected to the base of a transistor Q1 which constitutes the call detection circuit 14.

The terminals 11 and 12 are connected to each other by a push button switch provided in the intercom subunit. When the push button switch is off, the transistor Q1 is on and the collector exhibits a low level (hereinafter referred to as "L"). When the push button switch is on, the transistor Q1 is off and the collector is at a high level (hereinafter referred to as "H"). That is, the state of the pushbutton switch can be detected by the collector voltage of the transistor Q1.

The collector of the transistor Q1 is connected to the inverter I2 of the paging activation control circuit 15 via the inverter I1, the diode D2 and the resistor R9. The output terminal of the inverter I2 is connected to the reference potential point via the collector-emitter path of the transistor Q3. Transistor Q
Resistors R15 and R16 are connected in parallel to the collector-emitter path of 3, and the connection point of the resistors R15 and R16 is the transistor Q.
Connected to 3 bases. The voltage at the output end of the inverter I2 constitutes the ringing tone generating circuit 26, and the melody IC1
The power supply voltage is 6 and 17.

That is, the melody ICs 16 and 17 are inverters I
It becomes operable when the output terminal of 2 becomes "H". The reference terminals of melody ICs 16 and 17 are diode D, respectively.
It is connected to the output terminal Q and the inverting output terminal Q of the flip-flop 18 via 5 and D6, and either one of them operates according to the output of the flip-flop 18. Melody IC16,
Reference numeral 17 reads melody data stored in a ROM (not shown), converts it into a voice signal, and outputs it. The output of the melody IC16 is a capacitor C5 and a resistor R.
The output of the melody IC17 is output via the capacitor C7 and the resistor R14. Resistors R12, R
14 are commonly connected, and the output of melody ICs 16 and 17 is resistor R
It is supplied to the power amplifier 19 from the connection point of 12 and R14 via the capacitor C9 and the resistor R17.

The power supply terminal of the power amplifier 19 is connected to the power supply terminal 13 via the collector-emitter path of the transistor Q4, and the power supply voltage Vcc is turned on when the transistor Q4 is turned on.
Are being supplied. The power amplifier 19 is supplied with the power supply voltage, amplifies the audio signal from the melody ICs 16 and 17, and supplies the amplified audio signal to the primary winding of the transformer 20. Trance
The audio signal supplied to the primary winding of 20 is the hook switch S
It is output to the speaker terminal 21 via 2 and is also supplied to the speaker 22 via the secondary winding of the transformer 20.

In this embodiment, the melody is switched by the push button switch 23.
The power supply terminal 13 is connected to the reference potential point via the resistor R6 and the push button switch 23, and the connection point between the resistor R6 and the push button switch 23 is connected to the output terminal of the inverter I1 via the diodes D3 and D2. It Also, the power supply terminal
Reference numeral 13 is connected to the input end of the flip-flop 18 via the resistor R7, and the input end of the flip-flop 18 is connected to the connection point of the resistor R6 and the push button switch 23 via the capacitor C2. When the push button switch 23 is turned on, a trigger pulse is generated in the capacitor C2 and the output of the flip-flop 18 is inverted. flip flop
When the output terminal Q of 18 becomes "L", the melody IC
16 operates, and the inverting output terminal Q becomes "L", whereby the melody IC17 operates.

In the present embodiment, the ringing tone generating circuit 26
The connection point between the resistors R12, R14 and the capacitor C9, which is the output terminal of the transistor Q1, constitutes the ringing tone detection circuit 24.
It is also connected to the base of 2. The collector of the transistor Q2 is connected to the cathode of the diode D2, the emitter is connected to the reference potential point, and the base is also connected to the reference potential point via the diode D4. The collector of the transistor Q2 is also connected to the reference potential point via the smoothing capacitor C3. Transistor Q4 is a melody IC
It is turned on by the positive output from 16 and 17, and the collector voltage is set to "L". That is, when the voice signal is output from the melody ICs 16 and 17,
The output of the ringing tone detection circuit 24 is always "L".

The supply of the power supply voltage to the power amplifier 19 is controlled by the transistor Q4. The base of the transistor Q4 is a resistor R18 and an inverter I3.
It is connected to the output terminal of the inverter I2 via the switch I2 and is turned on when the output of the inverter I2 becomes "H". The power supply terminal 13 has a resistor R21 and a capacitor C10.
Is connected to a reference potential point via a resistor R21 and a capacitor C10, and is connected to a capacitor microphone 25 via a hook switch S1 and a resistor R22 which are interlocked with a handset of the main body (not shown). The connection point between the hook switch S1 and the resistor R22 is the resistor R20 and the inverter I.
It is also connected to the base of the transistor Q4 via 4 and the resistor R19, and the connection point between the resistor R20 and the inverter I4 is connected to the input end of the inverter I2 via the diode D7. That is, when the hook switch S1 is turned on, the condenser microphone 25 and the power amplifier 19
A power supply voltage is supplied to the inverter and the output of the inverter I2 is set to "L". The condenser microphone 25 is connected to the input end of the power amplifier 19 via the condenser C11.

Next, the operation of the embodiment thus constructed will be described with reference to the timing chart of FIG. 2 (a) shows the on / off state of the push button switch provided in the intercom slave, FIG. 2 (b) shows the output of the inverter I2, and FIG. 2 (c) shows the melody IC16,17.
2D, and FIG. 2D shows the collector voltage of the transistor Q2.

When the terminals 11 and 12 are in the open state by turning off the push button switch of the doorphone handset (not shown), the base of the transistor Q1 is "H".
Therefore, in this case, the collector of the transistor Q1 is "L". That is, when the push button switch of the intercom slave is off, the output terminal of the inverter I1 is "H", and the output terminal of the inverter I2 constituting the call activation control circuit 15 is "L". Therefore, the melody IC16,17
The power supply voltage is not supplied to the device and it is in the off state. The "L" output of the inverter I2 is inverted by the inverter I3 and applied to the transistor Q4. In this case, the transistor Q4 is also off and the power amplifier 19 is not supplied with the power supply voltage.

Here, it is assumed that the visitor pushes the push button switch of the intercom subunit to turn it on. Then, the base potential of the transistor Q1 drops and the transistor Q1 is turned off. The collector of the transistor Q1 is supplied with the power supply voltage from the power supply terminal 13 via the resistor R3, and the input terminal of the inverter I1 changes from "L" to "H", as shown in FIGS. As shown in, the output terminal of the inverter I2 also changes from "L" to "H". As a result, the power supply voltage is supplied to the melody ICs 16 and 17. When the inverted output terminal Q of the flip-flop 18 is "L", the melody IC17 operates, and when the output terminal Q is "L", the melody IC16 operates.

A melody voice signal is output from one of the melody ICs 16 and 17, and the voice signal is supplied to the power amplifier 19 via the capacitor C9 and the resistor R17. On the other hand, the "H" output of the inverter I2 is the inverter I
It is inverted by 3 and applied to the transistor Q4, and the transistor Q4 supplies the power supply voltage to the power amplifier 19. The power amplifier 19 amplifies the sound signal of the melody and gives it to the speaker 22 via the transformer 20. In this way, the melody is acoustically output from the speaker 22.

The visitor releases his / her finger for a predetermined time after turning on the push button switch to turn off the push button switch. Then, the collector voltage of the transistor Q1 returns to "L" again, and the output of the inverter I1 is "H".
become. However, in this case, the operation of the ringing tone detection circuit 24 maintains the input terminal of the inverter I2 at "L". That is, the output of either one of the melody ICs 16 and 17 is output through the connection point of the resistors R12 and R14 to the ringing tone detection circuit.
It is provided to the base of the transistor Q2 which constitutes 24. Transistor Q2 is a melody IC shown in FIG.
It turns on when the audio signals of 16 and 17 have a positive polarity. The transistor Q2 is turned off when the audio signal has a negative polarity, but the collector voltage of the transistor Q2 is maintained at "L" by the smoothing operation of the capacitor C3 (see FIG. 2 (d)). As a result, the output terminal of the inverter I2 maintains "H",
The melody ICs 16 and 17 continue to operate.

That is, once a melody is generated, the collector voltage of the transistor Q2 maintains "L" until the melody ends, regardless of the state of the push button switch of the intercom slave unit, and the power amplifier 19 receives the power supply voltage. Will continue to be supplied.

When the melody ends and the output of the voice signal from the melody ICs 16 and 17 stops, the transistor Q2 turns off and the collector voltage of the transistor Q2 gradually rises. When the collector voltage of the transistor Q2 exceeds the threshold value of the inverter I2, the output of the inverter I2 changes from "H" to "L", and the supply of the power supply voltage to the melody ICs 16 and 17 is stopped. Further, the output terminal of the inverter I3 changes to "H" and the transistor Q4 is turned off. As a result, the supply of the power supply voltage to the power amplifier 19 is stopped and the standby state is restored.

Now, assume that the handset of the main unit is picked up during or after the ringing tone is generated. Then, the hook switch S1 turns on and the power supply terminal
A power supply voltage is supplied from 13 to the condenser microphone 25 through the resistor R21, the switch S1 and the resistor R22. The "H" voltage appearing on the hook switch S1 is given to the input terminal of the inverter I2 via the resistor R20 and the diode D7. As a result, the output terminal of the inverter I2 is forcibly set to "L", the operation of the melody ICs 16 and 17 is stopped, and the output of the melody is stopped. On the other hand, in this case, the inverter I
Since the output terminal of 4 is "L", the transistor Q4 remains on. Therefore, the voltage is supplied to the power amplifier 19, and the audio signal from the condenser microphone 25 is amplified by the power amplifier 19 and output. Power Amplifier
The audio signal from 19 is the transformer 20 and the hook switch S.
It is transmitted to the intercom slave unit side via 3 and output as voice. When the handset is returned to its original position, the hook switch S1 turns off and the transistor Q4 turns off.
The supply of the power supply voltage to the power amplifier 19 is stopped and the standby state is restored.

As described above, in this embodiment, once the melody voice signal is generated from the melody ICs 16 and 17, the collector voltage of the transistor Q2 of the ringing tone detection circuit 24 maintains "L" until the melody ends. To do. As a result, the melody can be acoustically output to the end regardless of the OFF operation of the push button switch of the intercom slave. When the melody ends, the transistor Q2 is turned off, the supply of the power supply voltage to the power amplifier 19 is stopped, and the standby state is restored. A timer circuit with a large variation and an expensive other pin type melody IC are not adopted, and the end of the melody can be reliably detected and returned to the standby state by a simple and inexpensive configuration.

By the way, in this embodiment, two melody ICs 16 and 17 are provided, and the push button switch 23 is provided.
It is now possible to select either melody. Now, it is assumed that the output terminal Q of the flip-flop 18 to which the diode D5 is connected is "L" and the inverting output terminal Q to which the diode D6 is connected is "H". In this case, the melody IC16 is in an operable state. Here, for example, the push button switch 23 provided on the handset is turned on. Then, one end of the capacitor C2 whose terminal voltage was 0 is connected to the reference potential point, the terminal voltage on the input end side of the flip-flop 18 instantly changes to "L", and then returns to the original "H". To do. That is,
A trigger pulse is input to the flip-flop 18 by turning on the push button switch 23.

The output of the flip-flop 18 is inverted each time a trigger pulse is input. That is, the output terminal Q becomes "H", the inverting output terminal Q becomes "L", and a current flows through the diode D6 connected to the inverting output terminal Q, so that the melody IC17 becomes in the operating state. Thus, the melody of the ringing tone can be changed by switching the melody IC by operating the push button switch 23.

Furthermore, by connecting flip-flops to the output terminal Q and the inverting output terminal Q of the flip-flop 18, it is possible to select four melody ICs from the outputs of these flip-flops. Also in this case, these four melody ICs can be switched only by operating the push button switch 23. As described above, in the present embodiment, even when the number of melody ICs is increased, it is not necessary to provide a slide switch or the like which occupies a large space for selecting these melody ICs.
The music selection operation can be performed only by operating the push button switch 23. Therefore, a space for the operation switch for selecting a music can be reduced, and even if the operation switch is provided on the handset, the operability is not hindered.

By the way, unlike a slide switch or the like,
It is not possible to confirm which melody IC is selected simply by looking at the state of the push button switch 23. Therefore, in this embodiment, the push button switch
The melody is actually output by the operation of 23. That is, the connection point between the diode D2 and the resistor R9 is connected to the reference potential point via the diode D3 and the push button switch 23. In the standby state,
When pushbutton switch 23 is turned on, diode D2
The connection point between the resistor R9 and the resistor R9 is connected to the reference potential point via the diode D3, and the output terminal of the inverter I2 is forcibly set to "H". As a result, the melody IC1
Either one of 6 and 17 operates and the power supply voltage is also supplied to the power amplifier 19, and the selected melody is acoustically output.

[0038]

As described above, according to the present invention, a call detection circuit for detecting call information from a user and outputting a call detection signal in a waiting state; and a calling state from the waiting state in response to the calling detection signal And a ringing tone generating circuit for outputting a ringing tone; a ringing tone detecting circuit for detecting that the ringing tone is being output ;
Is detected , the ringing tone generating circuit is continuously operated to detect the ringing tone.
It is detected by the road that the ringing tone has been output.
The call activation control circuit for returning the call state to the standby state by the above is provided. Therefore, the ring tone is output to the end, and it is possible to surely return to the standby state after the termination of the ring tone. it can.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a telephone device according to the present invention.

FIG. 2 is a timing chart for explaining the operation of the embodiment.

FIG. 3 is a block diagram showing a conventional intercom device.

[Explanation of symbols]

14 ... Call detection circuit, 15 ... Call activation control circuit, 18 ... Flip-flop, 19 ... Power amplifier, 24 ... Call sound detection circuit, 26 ... Call sound generation circuit

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04M 9/00-9/10 H04M 1/00 H04M 1/725

Claims (6)

(57) [Claims] 1. A ringing detection circuit for detecting ringing information from a user and outputting a ringing detection signal in a standby state; and a ringing tone for shifting from the standby state to the ringing state and outputting a ringing tone by the ringing detection signal. A generating circuit; a ringing tone detecting circuit for detecting that the ringing tone is output ; and the ringing tone detecting circuit outputs the ringing tone.
If it is has been detected, the ringing tone generating circuit is operated to continue before by the ringing tone detecting circuit
By detecting that the output of the ringing tone has ended,
And a call activation control circuit for returning the calling state to the standby state. 2. The call activation control circuit includes a forced stop circuit for forcibly stopping the output of the ringing tone when the user activates the call while the predetermined ringing tone is being output. The communication device according to claim 1, wherein the communication device is a communication device. 3. The ringing tone detection circuit includes a transistor having a collector connected to the ringing activation control circuit, an emitter connected to a reference potential point, and a base to which the ringing tone is supplied; and a collector and an emitter. The communication device according to claim 1, further comprising: a capacitor connected therebetween. 4. The ringing tone generating circuit according to claim 1, wherein any one of a plurality of types of ringing tone is selected by a switching unit that generates a switching signal based on a user operation. Intercom. 5. The changeover means selects a make signal generating element for generating a make signal based on a user operation; an output polarity of the make signal is inverted by the make signal to select one of the plurality of types of ringing tones. The communication device according to claim 3, further comprising one or more flip-flops. 6. The make signal generation element is connected to an input end of the ringing activation control circuit, controls the ringing activation control circuit when the make signal is generated, and outputs a predetermined ringing tone to the ringing tone generation circuit. The communication device according to claim 4, wherein the communication device is generated.