JP3072429B2 - Timer control circuit in TV intercom system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a television intercom system, and more particularly, to a timer control circuit for setting a time for supplying power to a television camera and a monitor television. About what you did.

[Prior art] In order to be able to see the appearance of visitors indoors, a TV camera is installed on the intercom slave unit installed at the entrance, and a monitor TV is installed on the intercom master unit installed inside the room to talk. At the same time, a television intercom system capable of projecting images has been developed and used.

Such a television intercom system is, as shown in FIG. 3, an intercom slave provided at an entrance or the like.
When the call button 200a of the 200 is operated, a call signal is transmitted to the intercom master unit 100 provided in the room through the signal line l, a ring tone is output from the speaker 100c, and the TV camera 200b of the slave 200 and the master unit 100 monitor tv 100b
Is supplied with a current, a video signal is sent to the base unit 100 via the signal line l, and is displayed as an image on the monitor television 100b. When the resident picks up the handset and responds to the ringing sound, Speaker 200c and microphone 200
A call is made mutually by d.

By the way, in such a system, the master unit 100 and the slave unit 2
00 is connected by a plurality of signal lines l, but since the number of wirings increases and the laying work becomes large,
Recently, a television intercom system configured by multiplexing transmission of video, audio, control signals, and the like through a pair of signal lines 1 has been developed.

FIG. 4 is a block diagram showing the configuration of such a television intercom system.

This system is configured by combining an intercom master unit 100 having a monitor TV TV installed indoors and an intercom slave unit 200 having a monitor TV TVC installed at the entrance, both of which are coaxial cables. The power supply is supplied to the slave unit 200 from the master unit 100 side, and multiplex transmission of video, audio, and control signals is performed to communicate necessary information.

A more specific configuration will be described.
0 is a power supply circuit for the slave unit for supplying power to the slave unit 200 side.
101, Voice signal from handset H and intercom slave
A modulation unit 105 and a slave unit 20 that modulate a high-frequency signal with a tone signal serving as a control signal of a television camera TVC provided on the side 200.
The demodulator 104 demodulates the high-frequency signal transmitted from the 0 side to extract a calling signal and a voice signal, and inputs the high-frequency signal output from the modulator 105. Output the high-frequency signal transmitted from the side, transmit the output voltage of the power supply circuit 101 for the slave unit to the slave unit side, further,
A balanced input / output circuit 103 for outputting a video signal transmitted from the television camera TVC of the slave 200, and a calling signal generating circuit 102 for outputting a calling signal in accordance with the output signal of the tone signal detecting circuit 104c and sounding the calling signal from the speaker SPA. A timer circuit for driving the switching circuit 108 by outputting a drive signal for a first set time (approximately 30 seconds necessary for confirming the appearance of a visitor) using the output signal of the tone signal detection circuit 104c as a start signal ( I) 106, Timer circuit which is activated by switching of a hook switch (not shown) provided on hook F when picking up handset H and drives the switching circuit for a second set time (about 3 minutes required for a call). (II) 107, and the modulation unit 105 includes an output signal from an audio signal amplification circuit 105b that amplifies the audio signal to a certain level, and an output signal from a tone signal generation circuit 105c. The input signal and the input signal are input to the modulation circuit 105a, and the high-frequency signal serving as the first carrier is FM-modulated by these signals. Demodulation circuit 104a, and a configuration having a tone signal detection circuit 104c and a voice signal amplification circuit 104b in order to further extract a calling signal and a voice signal transmitted from the handset 200 side from the FM-demodulated signal. Has become.

Further, the other intercom slave 200 is a modulation unit 204 that modulates a high-frequency signal by a voice signal from the microphone M and a tone signal serving as a calling signal to the base unit 100, and a high-frequency signal transmitted from the base unit 100 side. A demodulation unit 205 that demodulates and extracts a camera control signal and an audio signal, a high-frequency signal output from the modulation unit 204 and a video signal output from the television camera TVC are input, and a high-frequency signal is output to the demodulation unit 205.
Further, a balanced input / output circuit 203 for outputting a power supply separation circuit 201 for separating the power supply current of the slave unit power supply circuit 101 from a high-frequency signal transmitted from the base unit 100 via the signal line l, and an output signal of a tone signal detection circuit 205c The power supply to the TV camera TVC is controlled by a camera power switch 202.The modulation unit 204 outputs an output signal from a microphone signal amplification circuit 204b that amplifies the microphone signal to a certain level, and operates a call button SW. The tone signal output from the tone signal generation circuit 204c and the tone signal output from the tone signal generation circuit 204c are input to the modulation circuit 204a, and these signals are used as a second carrier (a high-frequency signal that can be distinguished from the first carrier of the master unit) The demodulation unit 205 demodulates a high frequency signal from the balanced input / output circuit 203 by FM demodulation.
05a, a tone signal detecting circuit 205c and an audio signal amplifying circuit 205b for extracting a tone signal for controlling the camera and an audio signal from the demodulated signal.

In such a system, the master unit 100 and the slave unit 200 have connection terminals T1 and TG provided on the master unit side and connection terminals T2 and TG provided on the slave unit side, respectively, for a dedicated signal line l such as a coaxial cable. Connected by core wire and shield sheath wire respectively,
Video, audio and other control signals necessary for information communication are multiplex-transmitted between the two via the signal line l.

By the way, in the system having such a configuration, when the call button SW of the slave 200 is operated, a tone signal is output from the tone signal generation circuit 204c of the modulation unit 204, and the modulation circuit 204a
Then, the second carrier is FM-modulated with this tone signal. The modulated second carrier is sent to the base unit 100 via the balanced input / output circuit 203 and the signal line l, and is applied to the demodulation unit 104 via the balanced input / output circuit 103 on the base unit 100. At 104a
When FM demodulation is performed, the tone signal is detected by the tone signal detection circuit 104c, the calling signal generation circuit 102 sounds the speaker SPF of the base unit 100, and the timer circuit (I) 1
06 is activated and the switching circuit 10 is turned on for the first set time.
8 is driven to supply power to the monitor TV. At the same time, the output voltage of the switching circuit 108 is applied to the tone signal generation circuit 105c of the modulation section 105, and the call signal from the call signal generation circuit 102 is applied to the voice signal amplification circuit 105b. The first carrier is FM-modulated with the tone signal and the audio signal of the above, and the modulated wave is applied to the demodulation unit 205 through the balanced input / output circuit 103, the signal line l, and the balanced input / output circuit on the master unit side, and the audio signal amplification circuit The ringing signal is amplified by the speaker SPB, a back tone of the ringing tone sounds from the speaker SPB, and the tone signal detection circuit 205c
The camera power switch 202 is driven by the output signal of the TV camera TVC.
Supplied to

Therefore, at the same time as operating the call button SW on the child device 200 side,
Since power is supplied to the television camera TVC on the slave 200 and the monitor TV TV on the master 100 for the first set time,
The video signal from the TV camera TVC is supplied to the balanced input / output circuit 20.
3, monitor TV through signal line l, balanced input / output circuit 103
The video is sent to the TV and projected.

In this way, the called base unit 100 picks up the handset H from the hook F by the ringing sound from the speaker SPA before the first set time ends, and responds by setting the hook F. The timer circuit (I) 106 is reset by a hook switch (not shown), the timer circuit (II) 107 is activated, and the switching circuit 108 is driven for a second set time, so that the monitor television T
While the power is continuously supplied to V, the power to the television camera TVC of the slave 200 is also continuously supplied. Here, the voice responded by the resident with the handset H is amplified by the voice signal amplifier circuit 105b, sent to the modulation circuit 105a and FM-modulated the first carrier, and the FM-modulated first carrier is supplied to the balanced input / output circuit 103, The audio signal transmitted to the slave 200 through the coaxial cable 1 and FM-demodulated by the demodulation circuit 205a of the demodulation unit 205 through the balanced input / output circuit 203 of the slave 200 is amplified by the audio signal amplifying circuit 205b. The sound of master device 100 is output from speaker SPB of device 200.

The audio signal input from the microphone M of the slave unit 200 is amplified by the microphone signal amplifier circuit 204b and input to the modulation circuit 204a, where the second carrier is FM-modulated, and the balanced input / output circuit 203, the coaxial cable 203 l, Balanced input / output circuit on master unit 100 side
After being transmitted to the demodulation unit 104 through the demodulation unit 103 and demodulated, the audio signal is amplified by the audio signal amplification circuit 104b, and the handset H of the base unit 100 operates to output the audio of the handset 200 side. Then, when the call is finished and the handset H of the base unit 100 is returned, the timer circuit 107 is reset in conjunction with a hook switch (not shown), and the switching circuit 106 is turned off.
Since the power supply to the monitor TV is turned off and the driving of the tone signal generation circuit of the modulation unit 105 of the master unit 100 is stopped, the tone of the tone signal detection circuit 205c of the demodulation unit 205 of the slave unit 200 is stopped. The detection of the signal is stopped, the camera power switch 206 is shut off, and the supply of power to the television camera TVC is also stopped.

Therefore, in such a TV intercom system, when the call button on the handset 200 side is operated, when the resident is away, the TV camera TVC and the monitor TV T
Since the power supply is cut off after the power is continuously supplied to the V for the first set time, the fixed image is not displayed for a long time from the TV camera TVC to the monitor TV TV, and the monitor TV Is designed to prevent burning of the fluorescent screen and extend the life of the television camera.

When the resident picks up and answers the handset in response to the ringing tone, the timer circuit (I) 106 is reset, and the television camera TVC and the monitor television TV are replaced by the timer circuit (II) 107 for a second set time. Is turned on, and a call is made. When a call is made for the second set time or longer, the timer switch (II) 107 is restarted by operating the monitor switch MSW until the second set time elapses, and the TV camera TVC and the monitor TV are restarted. It is configured to continuously supply power to the TV.

However, the television intercom system having the above configuration requires two independent timer circuits (I) and (II) to control the first and second set times, so that the circuits are duplicated. The development of a timer control circuit capable of simplifying the circuit by a simple method and reducing the material cost is awaited because of the complexity and the increase in the material cost.

[Problems to be Solved by the Invention] The present invention proposed in view of the above situation is to change an external element connected to a timer circuit by a hook switch interlocked with a handset to change a set time of the timer. An object of the present invention is to provide a timer control circuit for a television intercom system in which a single timer circuit can switch and set two power supply times for a television camera and a monitor television. And

Means for Solving the Problems According to the present invention proposed to achieve the above object, a power supply time to a television camera provided on the intercom slave unit and a monitor television provided on the intercom master unit is defined. A timer circuit, and a hook switch interlocked with an up / down operation of the handset of the intercom master unit. The hook switch switches an external element externally connected to the timer circuit, and switches the timer circuit to a second state. 1. When the handset on the intercom master side is picked up, the timer circuit is reset and then set again when the handset on the intercom master side is picked up, while the handset returns to the original state. Sometimes, the timer circuit is configured in combination with a set / reset circuit for resetting the timer circuit. Corresponding to 1).

According to the second aspect of the present invention, a monitor switch is added to the timer control circuit, and when the switch is operated, the timer circuit is activated, and a television camera provided on the intercom slave unit side is activated. The drive current is automatically supplied to the monitor television provided on the intercom slave unit for a time corresponding to the set time of the timer circuit.

As an external element of such a timer control circuit,
A capacitor or a resistor is used (corresponding to claims 3 and 4).

[Operation] In the present invention, when the handset is in the return state, that is, when the handset is hooked, the switching means interlocking with the hook switch connects an external element for reducing the set time to the timer circuit. When a call signal is input from the intercom slave unit to the circuit, a drive signal is output from the timer circuit for a first set time, whereby the television camera provided on the interphone slave unit and the intercom master unit are provided. The power is supplied to the monitor television for the first set time.

Next, when the handset is taken up by the end of the first set time, the switching means interlocking with the hook switch connects an external element for increasing the set time to the timer circuit. After the reset signal is sent to the timer circuit, the set signal is sent again to the timer circuit.

As a result, the timer circuit outputs the drive signal for the second set time, so that the TV camera provided on the intercom slave device side and the monitor TV provided on the intercom master device side only output the drive signal for the second set time. Power is supplied.

Then, when the timer circuit elapses the second set time, the drive signal of the timer circuit is automatically stopped,
When the handset is returned to the original state before the second set time has elapsed, the set / reset circuit sends a reset signal to the timer circuit, and the television camera provided on the intercom slave side and the intercom master unit Immediately stop the power supply to the monitor TV provided on the side.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the configuration of a timer control circuit 1 according to the present invention. In the figure, reference numeral 1a denotes a timer circuit, 1b denotes a set / reset circuit for setting a timer circuit and sending a reset signal, and 1c denotes a switching means. Yes, in the example shown, a hook switch FSW that operates in conjunction with a handset (not shown)
By connecting another capacitor C2 in parallel to the capacitor C1 externally connected to the timer circuit 1a in advance by switching the contacts of the first and second contacts, the first set time (set to about 30 seconds) and the second It can be switched to a set time (set to about 3 minutes).

The set / reset circuit 1b detects a change in the state of the handset and outputs a set signal and a reset signal. When the handset is lifted, the set / reset circuit 1b outputs a reset signal and then outputs a set signal. Then, the timer circuit 1a is started, and when the handset is returned to the original state, a reset signal is output to reset the timer circuit 1a.

In the timer control circuit 1 having such a configuration, when a handset (not shown) is hooked on a hook (not shown), the hook switch FSW is switched to the side a.
The calling signal is used as a start signal of the timer circuit 1a,
, A drive signal is output from the terminal TOUT only during a first set time t1, and power is supplied to a television camera (not shown) and a monitor television (not shown) during this set time, The image of the visitor taken by the television camera of the intercom slave unit is displayed on the monitor television of the intercom master unit.

The intercom master unit confirms the visitor's image displayed on the monitor television, picks up the handset (not shown), and switches the hook switch FSW of the switching means 1c to the b side. C1
C2 is additionally connected in parallel, and the set time is the second set time t2
Is changed to

Also, in this example, at this time, a voltage is applied to the set / reset circuit 1b from the power supply voltage VCC through the resistor R by switching the hook switch FSW, so that the set / reset circuit 1b detects this change and outputs a reset signal. After that, the set signal is output, and the timer circuit 1a outputs the drive signal from the terminal TOUT for the second set time t2.

As a result, the power supply time for the television camera provided on the intercom slave unit side and the monitor television provided on the intercom master unit side is further continued for the second set time.

Also, the timer circuit 1a set to the second set time
However, if the call with the intercom slave unit is terminated and the handset is returned to the original state before the second set time elapses, the set / reset circuit 1b sets the timer circuit 1a.
Then, since the reset signal is output, the power supplied to the TV camera on the intercom slave device side and the monitor television on the intercom master device side is immediately stopped.

MSW is a monitor switch, and this switch MSW
When the is operated, regardless of the state of the handset, power is supplied to the television camera provided on the intercom slave device side and the monitor television provided on the intercom master device side.
In the case where the MSW is provided, the power supply time is the second set time by the switching means 1c when the handset is lifted, and is the first set time when the handset is in the return state. 2).

In the present invention, a hook switch linked to a handset
The capacitor C1 is switched to the timer circuit 1 by the FSW switching operation.
The first and second set times are produced by one timer circuit 1a by switching connection to a (corresponding to claim 3), but are externally connected to the timer circuit 1a in conjunction with the operation of the handset. It is also possible to adopt a configuration (corresponding to claim 4) in which the connection of the resistor is switched.

Next, FIG. 2 is a block diagram showing a configuration in a case where the timer control circuit 1 is incorporated in a television intercom system. I have.

[Effect of the Invention] According to the timer control circuit (corresponding to the one described in claim 1) of the present invention, the television camera on the intercom slave device side is linked to the operation of the handset provided on the intercom master device side. It is possible to switch the power supply time supplied to the monitor television provided on the intercom master unit side to two set times by one timer circuit,
The circuit can be simplified and a timer control circuit suitable for a television intercom system with reduced material cost can be provided.

In the timer control circuit according to the second aspect, power can be supplied to the television camera provided on the intercom slave device side and the monitor television provided on the intercom master device side irrespective of the state of the handset. When the handset is lifted, power is supplied for a second set time, and when the handset is in the return state, power is supplied for the first set time.

[Brief description of the drawings]

FIG. 1 is a block diagram of a timer control circuit of the present invention, FIG. 2 is a block diagram in which the timer circuit section is incorporated in a television intercom system, FIG. 3 is a basic configuration diagram of a conventional television intercom system, FIG. 4 is a block diagram showing the detailed configuration. [Explanation of Signs] 1. Timer control circuit 1a Timer circuit section 1b Set / reset circuit 1c Switching means A. Intercom master B. Intercom slave FSW Hook switch H. Handset l: Signal line SW: Call button TV: Monitor TV TVC: TV camera t1: First set time t2: Second set time C1, C2: External element (capacitor)

Claims (4)

(57) [Claims] An intercom master unit having a monitor television is connected to an intercom slave unit having a television camera by a signal line, and when a call button provided on the slave unit side is operated, the interphone slave unit is operated. Power is automatically supplied to the television camera on the device side and the monitor television on the intercom master device for the first set time, while the master device side is provided until the first set time ends. Taking up the handset provided in the above, it is a timer control circuit in a TV intercom system configured to be continuously supplied with power to the TV camera and the monitor TV for a second set time, A timer circuit that regulates the supply time of the drive power to the television camera and the monitor television, is activated by the calling signal of the slave unit, Switching means for switching the timer circuit to the first and second set times by a hook switch communicating with the operation of the handset, and when the handset of the intercom master unit is picked up, after resetting the timer circuit, And a set / reset circuit that outputs a signal for resetting the timer circuit when the handset returns to the original state while being set again.
Timer control circuit in TV intercom system. 2. A timer switch is added to the timer control circuit. When the monitor switch is operated, the timer circuit is activated to connect the television camera provided on the intercom slave unit and the intercom slave unit. The drive current is automatically supplied to the provided monitor television for a time corresponding to the set time of the timer circuit.
2. The timer control circuit according to 1. 3. The timer control circuit according to claim 1, wherein said switching means switches an externally connected capacitor to switch between the first and second set times. 4. The timer control circuit according to claim 1, wherein said switching means switches the first and second set times by switching an externally connected resistor.