JPH034655A - Intercom system - Google Patents

Abstract

PURPOSE:To allow a visitor to await a reply with ease by lighting a call display lamp provided to a slave set side while the visitor depresses a call button of a slave set to call a master set. CONSTITUTION:When a call button 16 is depressed, a call tone is sent to a master set and a back tone is sent to a slave set, and a voltage level of a power supply supplied from the master set via a transmission line 19 is changed depending on the state of standby of a doorphone, talking state and calling state. A driver 22 comprising a resistor 24 for current limit, a light emitting diode of a call display lamp 23 and an NPN transistor(TR) is connected in series with a power consumption circuit 13 and the emitter of the driver 22 connects to ground. Since a current flows to the TR during calling, a call display lamp 23 (light emitting diode) is lighted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a door phone, and more particularly to a door phone that allows confirmation from the handset side whether a base unit is calling.

[Conventional technology]

In recent years, voice door intercoms have been used to easily respond to visitors to a home and for security reasons, allowing for conversations without having to open the front door. With a door phone, a base unit inside the house is connected to a slave unit outside the entrance via a line, and a conversation can be made using the speaker and microphone installed on each base unit and slave unit.

For example, Figure 3 is a block diagram of a conventional door phone, where (1) is the main unit of the door phone, (2) is the handset for making and receiving calls, and (3) is a battery-powered system that transforms and rectifies 100 volts of AC. (4) is a power supply circuit that supplies a DC voltage of several to 10-odd volts, (4) is a slave unit (1
2) a call detection circuit that detects a call signal output from the call signal generation circuit (15) when the call button (16) is pressed;
5) is an amplifier for transmitting calls, (6) is a control circuit that controls each part of the doorbell, (7) is a ring tone generating circuit that notifies you of a call from a handset, and (8) is a circuit that generates call tone, ring tone, etc. A receiver amplifier for amplification, - (9) surrounded by a dotted chain line is a hook switch of the handset (2), (10) is an external speaker, and (11) a capacitor that cuts off the DC power source and extracts frequency components.

(13) is the transmission line (19) from the power supply circuit (3)
(14) is an audio circuit that modulates, demodulates, amplifies, etc. to transmit audio signals, (15) is a calling signal generation circuit. The circuit includes a call button (16), a speaker of the handset (17), and a microphone (18).

Next, the operation of transmitting signals such as voice of the conventional doorbell will be explained based on FIG. The visitor presses the call button (1) on the handset.
6), a calling signal is sent from the calling signal generation circuit (15) to the transmission line (19). Then, the call detection circuit (4) detects the call signal and notifies the control circuit (6) that there is a call. The control circuit (6) generates a ring tone from the external speaker (10) of the base unit via the ring tone generation circuit (7) and the amplifier (8), and returns the ring tone signal to the slave unit to output the ring tone to the slave unit. A ring tone also sounds from the speaker (17). Note that the ring tone returned to the handset is usually called a back tone.

Also, I noticed the ringing tone on the main unit side and set the handset (2).
When the hook switch (9) is turned off, the line for receiving calls is switched from the external speaker (10) to the handset (2), and the switching state of the hook switch (9) is transmitted to the control circuit (6).

Then, the control circuit (6) determines whether the doorbell is on standby, talking, or ringing based on the states of the ring detection circuit (4) and the hook switch (9), and determines the voltage level supplied by the power supply circuit (3). to provide efficient power supply. For example, normally the ring time is set to 30 seconds and the call time is set to end after about 3 minutes, so the voltage level is kept low during the longest standby period, and the voltage level increases in the order of active call and ringing. It is changing to. In the case of normal operations, the state in which the equivalent operation is not performed is in standby, the state in which the handset (2) is called after the call button (16) is pressed until the handset (2) is picked up (off-hook), and the state in which the handset (2) ) is returned (on-hook) and the call ends.

In addition, the audio from the base handset (2) during a call is amplified by the amplifier (5), and then sent to the transmission line (19).
The signal then enters the audio circuit (14) and is emitted from the speaker (17). The voice from the handset is transmitted from the microphone (18) through the audio circuit (14), through the transmission line (19), is amplified by the receiver amplifier (8), and is output from the handset (2).

In addition, in order to prevent the sound from leaking when the handset (2) is hooked to the hook switch (9),
Control circuit (6) to turn on/off the transmitting amplifier (5)
I'm doing it.

Furthermore, more recently, video door intercoms have been developed and are becoming more popular, with the handset equipped with a TV camera and the base unit equipped with a monitor to provide video functionality, allowing you to have a conversation while viewing the image of the other person at the entrance. .

[Problem to be solved by the invention]

As mentioned above, with conventional door phones, when a visitor presses the call button on the handset, a ring tone is sounded from the external speaker on the base unit and the speaker on the handset is also played with a back tone, but the caller does not actually call. Is there one? or,
There was no way to know whether the doorbell was ringing (usually for about 30 seconds) or not, which caused anxiety for visitors and caused inconveniences such as having to press the call button many times.

The present invention was made with the aim of solving the above-mentioned problems, and when a visitor presses the call button on the handset to put the base unit into a calling state, the handset side can notify the base unit of the call status. The purpose is to provide a doorbell that allows you to know the doorbell.

[Means to solve the problem]

In order to solve the above problems, the door phone of the present invention includes a voltage level detection circuit that operates a driver only during a call based on the voltage level supplied from the power supply circuit to the handset during a call;
The device is equipped with a call indicator lamp that lights up when the driver is activated by the voltage level detection circuit.

[Effect]

According to the door phone according to the above means, the driver can be operated only during a call by detecting the voltage level supplied from the base unit during a call. Therefore, the call lamp can be turned on only during a call without providing a special timer circuit or the like.

Therefore, it is convenient for visitors to be able to know two things by checking the lighting of the call indicator lamp on the handset side: whether the call is being made reliably on the base unit, and whether the call status is continuing. [Embodiment] A preferred embodiment of the door phone according to the present invention will be described below based on the drawings.

The configuration of the base unit of the door phone according to this embodiment is the same as that of the base unit shown in FIG. 3, so a redundant explanation will be omitted, and FIG. 1 shows only a block diagram showing the configuration of the slave unit.

In the handset of this embodiment shown in FIG. 1, the power supply circuit (13)
, the audio circuit (14) and the calling signal generating circuit (15) are the same as those shown in FIG. 3, and therefore, repeated explanation will be omitted.

In this embodiment, (20) is a voltage dividing resistor that produces a reference voltage, (21) is a voltage level detection circuit that compares the supply voltage with the reference voltage and operates the driver (22) when it detects the voltage level during ringing. (23) is a call indicator lamp that lights up when the driver is operated, and (24) is a current limiting resistor.

The driver (22) uses an NPN transistor here, and the voltage level detection circuit (22) uses a reference voltage of 8.
When a voltage level is detected during a call, a current is supplied to the base of the transistor to provide a high level signal. Therefore, until the call button (16) on the handset side (12) is pressed and the handset on the base unit is picked up (off-hook),
Alternatively, during a call (approximately 30 seconds), the transistor operates and a collector current flows, which can light up the light emitting diode of the call indicator lamp (23) connected in series with the driver (22). Note that the driver (22) is not limited to a transistor, but may be anything that has a switching action that can be controlled by the voltage level detection circuit (21).

Here, as shown in FIG. 2, the DC voltage of the power supply supplied from the transmission line (19) is during calling (IOV),
The voltage level is set so that it decreases during a call (6V) and during standby (2V).

This is basically to suppress power consumption during standby, when no operation is required, and to provide efficient power supply.

The reference voltage a serving as a detection standard in the voltage level detection circuit (21) is set to (8V), and the reference voltage A is set to (4V).

In the voltage level detection circuit (21), the voltage of the power supply and the reference voltage are compared, and a voltage lower than the reference voltage A indicates standby, a voltage higher than the reference voltage A and lower than the reference voltage A indicates the call is in progress, and a reference voltage 8 indicates that the voltage is on standby. If the voltage is higher than that, it is determined that the call is in progress.

Next, the operation of the above embodiment will be explained.

When the call button (16) is pressed, the ring tone is sent to the base unit and the back tone to the slave unit, and from the base unit to the transmission line (
19) The voltage level of the power supplied through the doorbell is changed depending on whether the doorbell is on standby, on a call, or on a call. The configuration up to this point is the same as the configuration shown in FIG.

The power supplied is from the transmission line (19) to the power supply circuit (
13) to a constant voltage, and the voltage dividing resistors (20a) and (20
b) and (20c), the reference voltages a and b are generated and input to the voltage level detection circuit (21), while the transmission line (19)
), the voltage level is detected by comparing it with the voltage level of the power supply directly input to the voltage level detection circuit (21).

In addition, a current limiting resistor (24) is connected to the power supply circuit (13).
The light emitting diode of the call indicator lamp (23) and the driver (22) made of an NPN transistor are connected in series, and the emitter of the driver (22) is grounded.

The output side of the voltage level detection circuit (21) and the base of the transistor are connected, and when the voltage level detection circuit (21) detects the voltage level during calling, a high level (H) signal is sent to the driver (22) (base of the transistor). ), and the driver (22) is activated (transistor is on). Therefore, during a call, current flows through the transistor, so that the call indicator lamp (23) (light emitting diode) lights up.

As described above, in the doorbell of this embodiment, while the call button on the handset is pressed and the base unit is in the ringing state, the call indicator lamp provided on the handset side lights up and the call is not activated. It is possible to inform the visitor of what is actually happening and also to know whether the call is ongoing or not. Therefore, the visitor can wait for the person in the house to respond with peace of mind. Further, if there is no response after 30 seconds have elapsed during the call and the call display lamp goes out, it is convenient because it can be used as an indication that the caller is away.

Further, since the call is detected by a change in the voltage level, a complicated circuit such as a timer is not required.

In this embodiment, the present invention was implemented with respect to a door intercom that communicates only by voice, but it is also possible to implement the same in the same way by configuring the above circuit in a video door intercom which is currently becoming popular.

〔Effect of the invention〕

As explained above, in the doorbell according to the present invention, while a visitor presses the call button on the handset to call the base unit, the call indicator lamp provided on the handset side lights up, so that the base unit is activated. This is convenient because it shows that the call has actually been made and that the call status is continuing, and the visitor can now wait for a response with peace of mind.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a door intercom handset according to an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between voltage levels and reference voltages in the state of the door intercom, and FIG. 3 is a block diagram of a conventional door intercom. In the figure, (1) is the main unit, (3) is the power supply circuit, (
12) is a slave device, (20) is a voltage dividing resistor, (21) is a voltage level detection circuit, (22) is a driver, and (23) is a call indicator lamp. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A call button provided on the handset; a call signal generation circuit that generates a call signal when the call button is pressed; a call detection circuit that detects the call signal; There is a hook switch that puts the handset and base unit into a talking state, and depending on the output from the ringing signal detection circuit installed in the base unit and the state of the hook switch, the doorbell can be activated when the doorbell is on standby, during a call, or when the phone is talking.
a control circuit that detects when a call is in progress and controls a power supply circuit to change the voltage level of the power supply; A doorbell comprising: a voltage level detection circuit that detects a call and operates a driver only during a call; and a call indicator lamp that lights up when the driver is activated.