JPH02266744A - Two-wire type video interphone system - Google Patents

Abstract

PURPOSE:To simplify a circuit and to perform speech between master equipment and slave equipment successively by providing a dummy load part and a switching part which controls connection with the master equipment. CONSTITUTION:A master equipment operation detecting part 26 outputs the detection output to a master equipment selecting part 25 by detecting the master equipment 4 which performs off-hook, and the master selecting part 25 separates the master equipment 4 which continues the outputting of a voltage in operation from the dummy load part 32 by controlling the switching part 31, and connects the master equipment connection line 29 of the master equipment 4 to a connection line 27, and continues the transmission of the application of the voltage in operation on the slave equipment 1. Simultaneously, the master equipment 4 on which initialization is applied is connected to the dummy load part 32, and the master equipment connection line 29 of the master equipment 4 is separated from the connection line 27. In such a manner, the circuit can be simplified, and also, the voltage in operation can be continued to transmit to the slave equipment 1 by always selecting the master equipment 4 appropriately after the start-up of the master equipment 4 by the slave equipment 1 is performed, and the speech between the master equipment 4 and the slave equipment 1 can be performed successively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a two-wire digital/bi-intercom system with multi-station capabilities.

[Conventional technology] In order to make it possible to see the guests indoors, a monitor TV camera is installed at the entrance,
A television intercom system was developed and used in which a monitor was installed on the base unit installed indoors, and the video was captured by a monitor television camera and displayed at the same time as a call was made. As shown in Fig. 6, such a TV intercom system has become so popular that when you operate the call button 2 of the cordless handset 1 installed at the front door, a transmission line 3 is installed in the room. t = A calling signal is transmitted to the base unit 4, a discharge sound is output from the speaker 5 provided in the base unit 4, power is supplied to the monitor TV camera 6 of the slave unit 1, and the The video signal from the TV camera 6 is sent to the base unit 4 through the two-wire transmission line 3, and the video is output on the monitor I/via.When the resident picks up the handset 8 and answers the call, the call is made. It is now possible to do so.

Fig. 7 shows the circuit block of the digital intercom system shown in Fig. 6, where the system unit 24: has a main unit 4 equipped with a monitor TV 1/via installed indoors, and a base unit 4 installed at the entrance. A slave device 1- having a monitor television camera 6
Both bars of the base unit 4 and slave unit 1 are connected by a transmission line 3, and power is supplied from the base unit 4 to the slave unit 1 side through the transmission line 3. In addition, necessary information can be communicated by multiplexing the video signal from the monitor TV camera 6 from the handset 1, the call signal, or the voice signal between the base unit 4 and the handset 1. ing.

More specifically, the base device 4 includes a power superimposing circuit 9 for supplying power to the handset 1, a modulation section 10 that modulates a high-frequency signal using a call voice signal from the handset 8, and a modulation section 10 for modulating a high-frequency signal using a voice signal sent from the handset 1. A demodulator 11 demodulates the modulated signal and extracts a call audio signal, and a video signal receiver 12 receives the video signal sent from the slave R1 and outputs it to the monitor television 7. a call detection section 13 that receives an unsent call signal and generates a speaker ringing signal; and a balancing circuit that is interposed between the circuit group and the transmission line 3 and balances unbalanced signals of the circuit group. 14 and a short circuit protection circuit 45. The modulation unit 10 inputs a call voice signal from the handset 8 to a modulation circuit 10a, modulates a high-frequency carrier wave f1 serving as a first carrier wave, and sends it out to the transmission line 3 through a bandpass filter 10b and an equalization circuit 14. The demodulation section 11 has a balancing circuit 14.
It has a bandpass filter lla that limits the frequency band of the modulated signal from the audio signal, a demodulation circuit 11b that demodulates the modulated signal, and an audio signal amplification circuit 11c, and the audio signal amplification circuit 11c has a bandpass filter lla that limits the frequency band of the modulated signal from the audio signal amplification circuit 11c. The configuration is such that the call voice of handset 1 is output from handset 8 by signal output.

- The male device 1 includes a power separation unit 15 for separating the internal power of the handset 1 and the power of the monitor television camera 6 from the multiplexed signal sent from the parent device 4 via the transmission line 3, and a microphone 1.
6, a demodulator 18 that demodulates the modulated signal sent from the base unit 4 side and extracts a call audio signal, and an image from the monitor television camera 6. Signal to video filter times N19
A video circuit that sends data to the base unit 4 through the
a calling signal generation circuit 19 that notifies the base unit 4ff1 of a call by the operation of , and a balancing circuit 2 that is interposed between the circuit group and the transmission line 3 and balances unbalanced signals of the circuit group.
0 and a non-polarization circuit 44. The modulation unit 17 inputs the output signal from the microphone signal amplification circuit 17a that amplifies the microphone signal to a certain level to the modulation circuit 17b, and converts it into a second carrier wave (a high-frequency carrier wave that can be distinguished from the first carrier wave f+ on the IIL machine 4 side). ) is configured to modulate the high frequency carrier wave f2 and send it out through a band pass filter L7c, and the demodulator 18 includes a band pass filter 18a that limits the frequency band of the modulated signal from the balancing circuit 20. It has a demodulation circuit 18b for demodulating this modulated signal, and an audio signal amplification circuit 18c,
The speaker 21 is configured to output notification audio from the base unit 4 by outputting a notification audio signal from the audio signal amplification circuit 18c.

The power source separation unit 15 also includes a power source separation circuit 15a that separates the power source from the multiplexed signal sent from the base unit 4 (11), and a power source separation circuit 15a that detects a significant change in the power output value from the power source separation circuit 15a and detects a significant change in the power output value from the power source separation circuit 15a and detects a significant change in the power output value from the power source separation circuit 15a. 6, and a shunt regulator 15c to keep the supplied power current constant.

Such a master unit 4 and slave unit 1 have connection terminals T, T,' provided on the FA machine side and connection terminals T2 provided on the slave fil side.
．． T2'' are each connected by a transmission line 3 made of parallel electric wires, etc., and as mentioned above, the transmission line 3 is used to connect the base unit 4 and slave unit 1 with video signals necessary for information communication in addition to power supply. The call voice signal and the calling signal are multiplexed and transmitted.

By the way, in the intercom system configured as described above, when the call button 2 of the handset 1 is operated, the discharge signal generation circuit 4 is activated.
6 and outputs a calling signal.

This calling signal is sent to the base unit 4rs via the balancing circuit 20, the non-polarizing circuit 44, and the transmission line 3, and the Jl! The signal is applied to the call detection section 13 via the balancing circuit 14 of the device 4, and causes the speaker 5 of the base device 4 to sound as a call signal.

In the base unit 4 ff1q that is called in this way, the speaker 5 sounds and the superimposed voltage value to the power superimposing circuit 9 changes from the standby voltage value necessary for the calling operation on the slave unit 1 side to power the monitor TV camera 6. Supply l: The constant current is supplied to the handset 1 by switching to the required operating dark voltage value. This constant current output is transmitted to the power supply disconnection circuit 15a in the handset
The camera power switch 15t is outputted and the camera power switch 15t is activated, and power is supplied to the monitor television camera 6 through the shunt 1/gu1/-shunt X5c to drive the monitor television camera 6.

When the monitor television camera 6 is driven, the video signal is sent from the video filter circuit 19 to the balancing circuit &! 820, it enters the balancing circuit 14 on the base unit 4 side via the transmission line 3, is sent to the monitor television 7 through the video signal receiving section 12, and the video is displayed on the monitor television 7. Te hand (Call audio from Knit 8 No. 13 4: J,
A first carrier wave is FM modulated by a modulation circuit 10a having a first carrier wave f.

is transmitted from the bandpass filter 10b to the slave unit 1@ via the balancing circuit 14 and the transmission line 3. On the other hand, the slave unit 1 that receives this carrier wave f+g) signal depolarizes the modulated wave. It is inputted to the demodulation circuit 18b through the circuit 44, the balancing circuit S20, and the bandpass filters 1, 1□'3a of the demodulation section 18, and the modulated wave of the first carrier wave f is FM demodulated and a 7 call sound multiplex signal is output. get. Subsequently, this call voice signal is amplified by the voice signal amplification circuit 18e''c, and the call voice from the base unit 4 is outputted from the line 21 of the handset 1.

In addition, the voice signal from the microphone 16J on the handset 1 side is amplified by the microphone f signal amplification circuit 172] and input to the modulation circuit [71]. The carrier wave f2 is FM-modulated and transmitted from the bandpass filter 17c through the depolarization circuit 44, the balancing circuit 20, and the transmission line 3, and further l! The audio signal J4 is sent to the demodulation unit 11 through the balancing circuit i14 on the a4 side and is IN-tuned by the demodulation circuit 11b.
Amplified tiq path 11 (, amplified by ft ff1lls14
Output the call audio from the handset 8.

, Nikoteko, Kamiunete 1/Biinterphone System De 11
The first carrier wave f1 and the second carrier wave f are selected to have a frequency higher than the video signal frequency band of the monitor television camera 6 in order to prevent interference.

FIG. 8 is a diagram showing the relationship between the frequencies of these signals, and shows a direct current power supply voltage DC, a video signal V having a frequency band of several MHz, and a first carrier wave f of a higher frequency. , the modulated wave a from the base unit 4 and the second carrier wave f
2, the modulated wave from handset 1 is set to a different frequency. : These signals are multiplexed through three channels for transmission.

[Problems to be Solved by the Invention] By the way, the conventional system described in - is a system of January 1 with a base unit 4 and a slave unit 1, but such a standby (operating voltage and operating voltage A two-wire TV intercom system is used in which the number of handsets is switched according to calls from handsets, and the relationship between handsets and bases is 1:N, N:1, or N.
There are systems with multi-station configurations such as N-to-N systems; however, there are only systems using 15-pole transmission lines with complicated configurations.The present invention was made in view of the problems mentioned above. It's something! ! i
It is a two-wire system that allows multi-stationing using a simple configuration, and can prevent transmission voltage collisions when multiple base units are connected (by detecting off-hook of the handset of the base unit). The purpose is to provide a TV intercom system, and when multiple base units are installed, standby voltage can be transmitted only by the base unit set at the initial stage.
～Maybe the master unit transmits standby voltage depending on the initial setting 3! No matter which base unit is in the call state, the voltage during operation can be continuously transmitted from the mv1 without causing a collision depending on the voltage, and as a result, the handset of the base unit becomes off-hook. 2fi allows you to continue calling up to
The aim is to provide a standard TV intercom system, and the circuit configuration of the buffer amplifier section, dummy load section, and switching section is shared between the two base units, simplifying the circuit. The purpose of the present invention is to provide a 2-wire TV intercom system that is capable of providing a 2-wire TV intercom system that does not require standby voltage to be transmitted from the base unit, and therefore does not require transmission settings at the initial stage. The purpose is to.

[Means for Solving the Problems] The present invention provides a slave device equipped with a monitor television camera, a parent device equipped with a monitor television, and a device that connects the parent device and the slave device to transmit video signals from the slave device and the parent device. It consists of a two-wire transmission line that transmits voice signals between the handset and handset, and during standby, a constant standby voltage is supplied to the handset via the transmission line, and when the handset's calling means is operated, the main unit is called. When a call is made to the slave unit, the standby voltage value is instantaneously changed in conjunction with the operation of the calling means of the slave unit, and this change notifies the base unit of the call. A two-wire television intercom system that supplies operating voltage to a machine via a transmission line for a certain period of time, the system comprising one or more base units and one or more slave units, each of which has at least a plurality of slave units. In addition, a relay adapter is provided between the base unit and the slave unit, and each relay adapter is provided corresponding to each slave unit to be connected, and detects changes in standby voltage to the corresponding slave unit. a handset operation detection section that generates a control output; a handset selection section that enables the transmission of operating voltage and signals to the handset that receives a call operation based on the output of the handset operation detection section; A base unit operation detection unit is provided corresponding to each unit and detects off-hook information of the handset of the base unit transmitted through the transmission line, and a base unit that is in a call is selected based on the detection output of the base unit operation detection unit. A base unit selection unit that at least enables transmission of operating voltage from the base unit to the slave unit, a buffer amplifier unit that transmits a signal in one direction from the slave unit to the base unit, and a buffer amplifier unit that absorbs the operating voltage to be transmitted. This device includes a dummy load section for controlling the connection between the dummy load section and the master device, and a switching section for controlling the connection between the dummy load section and the base device.

Further, the invention according to claim 2 is the invention according to claim 1, in which the master device is initially set in advance to be disconnected from the dummy load section by the switching section during standby, through the master device selection section and the slave device selection section. The standby voltage is transmitted to each slave unit, and the standby voltage from other base units is connected to the dummy load unit at the switching unit, and the slave unit operation detection unit responds to a call from any slave unit. The detection output controls the handset selection section to supply voltage during operation only to the handset that is called.
In response to the calling operation of the handset, the standby voltage change is transmitted through the handset selection section and the master selection section, and the remaining voltage is transmitted through the handset selection section, buffer amplifier section, dummy load section, and switching section. The change in standby voltage is transmitted to the other base units, all base units are activated, and each base unit can supply operating voltage, and each P! Each base unit operation detection unit corresponding to the machine detects a base unit that has stopped outputting the operating voltage within a certain period of time, and connects the detected base unit to the dummy load unit via the switching unit, and then outputs a constant voltage. The master unit that is still supplying the operating voltage even after the lapse of time is separated from the dummy load unit by the switching unit, and connected to the master unit selection unit to transfer the operating voltage supplied from the master unit to the master unit selection unit and the slave unit. The information is supplied to the handset that performs the calling operation through the machine selection section.

Furthermore, the invention according to claim 3 is the invention according to claim 1, in which two TF1 machines are provided, and when one of the two base units is connected to the base unit selection section, the other base unit is always selected. is connected to the dummy load section via the switching section, and the buffer amplifier section, dummy load section, and switching section are connected to the two ? ! It was shared on the machine.

Further, the invention according to claim 4 is the invention according to claim 1, in which the values of the standby voltage and the operating voltage are equal, but the current values or the times during which the current continues to flow are different between the standby state and the operating state. .

The invention according to claim 5 disconnects the relay adapter and the base unit during standby, transmits standby voltage from the relay adapter to the slave unit, and connects the relay adapter and the base unit when a call operation is performed on the slave unit. It is something to do.

Still further, the invention according to claim 6 is the invention according to claim 1, in which the off-hook information of the handset of the base unit is transmitted from the base unit to the relay adapter at a frequency other than that of the video signal and the audio signal.

The invention set forth in claim 7 is the invention set forth in claim 1, in which off-hook information of the handset of the base unit is multiplexed into an audio signal transmitted from the base unit to the slave unit, and the audio signal is transmitted to the relay adapter.

The invention according to claim 8 is the invention according to claim 1, in which the slave unit and the relay adapter are in a connected state at the time of initial setting; (1) the relay adapter and the base unit are in a separated state; and (17) the slave unit and the relay adapter are in a disconnected state during standby. The relay adapter transmits the standby voltage to the machine from the relay adapter, detects the discharging operation of the r-machine, and connects the relay adapter and the master machine when the slave machine operation detecting section detects this.

[Function] According to the present invention, in addition to providing at least a plurality of either the base unit or the f unit, a relay adapter interposed between the base unit and the slave unit is provided, and a call from the slave unit is received by the relay adapter. In response to this, the call is relayed to the base unit, and the transmission voltage of the slave unit that performs the calling operation is set to the operating dark voltage, so the relay adapter connects the base unit and slave unit on a one-to-one basis. A two-wire television intercom system can be used to connect multiple base units and multiple slave units, or multiple base units and one slave unit, or one base unit and multiple slave units. Since it is possible to horizontally build a multi-station system such as a slave unit, the second function is possible. ). In particular, the operating dark voltage from the base unit that does not need to be transmitted to the slave unit can be absorbed by the dummy load section provided in the medium-phase adapter, so that it is possible to absorb the operating dark voltage from the base unit that does not need to transmit the operating dark voltage to the slave units, and to ``The operating dark voltage is applied to the f machine at 17,
- There is no problem with operation. In addition, the base unit operation detection unit and the base unit selection unit select the base unit and instruct the slave unit to operate as long as at least one base unit is off-hook. By continuing to transmit voltage, the cordless handset can be operated continuously, and the TV interbon can be operated (32).

Furthermore, in the invention as set forth in claim 3, the circuit configurations of the buffer amplifier section, dummy load section, and switching section are shared between the two base units, so that the circuit can be simplified.

In the invention as claimed in claim 5, the standby voltage is transmitted to the handset by a relay adapter.

As a method of transmitting the off-hook information of the handset of the base unit, it is also possible to transmit the off-hook information from the base unit to the relay γ adapter at a frequency other than the video signal and the audio signal as in the invention as claimed in claim 7, or as in the invention as claimed in claim 7. ) may be multiplexed into the audio signal transmitted from the base unit to the slave unit and transmitted to the relay adapter. According to method t>, the two-wire transmission line can be used as is. / Connection between the parent device and the relay adapter,
The connection between the base unit and the relay adapter is such that the slave unit and the relay adapter are in a connected state at the time of initial setting as in the invention of claim 8.
1. Separate the relay adapter and base unit. The relay adapter transmits the status and the standby voltage to the 7-machine during standby from the relay adapter, and when the discharge operation of the f machine is detected and detected by the slave machine operation detection section 7, the relay adapter and the main unit.

Furthermore, the standby voltage and the operating dark voltage are defined as the values of the standby voltage and the operating dark voltage as defined in claim 9. may be different.

1-Example 1 Hereinafter, the present invention will be explained with reference to Examples.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, in which a plurality of base units 1 . . . . are connected by transmission lines 3' . . . to form a system configuration 1.

FIG. 2 more specifically shows the relay adapter "22" LI,
This is a block diagram showing the transmission line 3 connected to the f machine 1...
... is the handset selection section 23 in the relay adapter 22.
are connected to the slave device connection lines 28 . . . , and each slave device connection line 28 . On the other hand, the transmission line 3 connected to the base unit 4...
... is the main unit connection line 29 in the relay γ adapter 22.
are connected to the base unit selection unit 25 through @What is the selection section 25?2
The connection line 27 is connected to the connection line 27.
The slave device selection section 23 side is the input, and the dummy load section 32 connected in parallel to the output terminals of the four unidirectional buffer amplifier sections 30... and the five buffer amplifier sections 30... is cut out. The parent machine connection line 29 is connected to the main unit through a circuit with the section 31...
To explain the operation of this 21'A circuit connected to..., during standby, the switching unit 32 of the base unit 4... is controlled by the control signal S of the base unit selection unit 25. It is separated from the dummy load section 31 at ..., and connected to the transmission line 3 and the main device connection line 29.
, the base unit selection unit 25, the connection line 27, the slave unit selection unit 23, the slave unit connection line 28..., the transmission line 3'...
A standby voltage is applied to each slave unit 1 from one base unit 4, which is initially set to be connected in a DC manner to the terminals 1 and 1.

When the call button 2 of the current slave unit 1 is operated, the standby voltage is forcibly dropped instantaneously by the slave @1, and this voltage drop causes the relay adapter 22 corresponding to the slave unit 1 to operate the slave unit. It is detected by the detection unit 24.

In addition, the voltage change during standby is 3 degrees on the transmission line, 28 on the slave connection line,
After passing through the slave device selection section 23, the connection line 27 and the master device selection section 25
, the base unit connection line 29, the path of the transmission line 3, the connection line 27, the buffer amplifier section 3 for the modulated waves of the video signal and the call audio signal.
0..., dummy load section 32..., switching section 31
. . , are transmitted to the base unit 4 via the base unit connection line 29 and the transmission line 3 route, respectively. Here, when the handset operation detection section 24 detects a voltage drop during standby, the detection output is transmitted to the handset selection 23, and the transmission line 3' of the handset 1 whose call button 2 is operated is connected to the handset. Line 28 and relay adapter 2
2 is connected to the connection line 27 in the handset selection unit 23 with low loss.

In addition, all base units 4 activated by detecting the change in voltage during standby.
. . . The switching section 32 . The operating voltage is transmitted from the base unit 4 to the transmission line 3, the base unit connection line 29, the base unit selection section 25, the connection line 27, and the slave unit selection section 2.
3. The video signal of the slave 8!1 is transmitted to the slave 1 whose call button 2 is operated via the slave unit connection line 28 and the transmission line 3';
Enables transmission of telephone voice signals.

In addition, the transmission line 3 of the activated base unit 4 other than the above...
The switching unit 32 controlled by the base unit selection unit 25
Since the dummy load section 31... is connected through two connection lines for the 11 machines, it is disconnected from the connection line 27, and voltage is supplied during operation using the dummy load section 31... as a load. Continue to do so.

As described above, the television intercom system of the present invention completes the start-up operation and shifts to the call operation. By the way, the FF 1 machine 4... that has transitioned to call operation performs a timer operation, and the handset 8 of the base unit 4... is forced to shut down in about 30 seconds when on-hook, and for about 3 minutes when off-hook (during a call). The call operation is now terminated. On the other hand, since the relay adapter 22 does not monitor the on-hook/off-hook states of the handsets 8 of the base units 4, etc., the transmission line 3 of each base unit 4...
The main unit operation detection unit 26 determines whether the line voltage of the main unit connection line 29 connected to the main unit connection line 29 is the operating voltage value or the standby voltage value.
Judgment is made by detecting and comparing the operating voltage, and if it is the voltage during standby, it is considered to be in a non-talking state. Instead of the base unit 4 which is initially set to supply voltage during operation,
If it is another ff1 device 4, you can talk within 30 seconds, which is the operating period of the initial setting base unit 4, but if it is longer than that, the operating voltage will be applied from the initial setting base unit 4. If this continues, you will not be able to make calls.

Therefore, before the initial setting of the base unit 4 finishes transmitting the operating voltage, the base unit operation detection unit 26 detects the base unit 4 that is off-hook the handset 8 (for example, the base unit 4 that is in the middle of a call). Detect and parent fi! ! Outputting the detection output to the selection section 25,
The switching unit 31 is controlled by the base unit selection unit 25 to disconnect the base unit 4 that continues to output voltage during operation and the dummy load unit 30, and connect the base unit connection line 29 and the connection line 27 of the base unit 4. Connection is made with low loss through the base unit selection section 25, and the slave unit 1...
・Continue applying and transmitting the operating voltage to. At the same time, the initialized base unit 4 and the dummy load section 30 are connected, and the base unit connection line 29 and the connection line 27 of the base unit 4 are separated by the base unit selection unit 25.

By monitoring the hook state of the handset 8 of the base unit 4 by the base unit operation detection unit 26 as described above, the base unit 4 is appropriately selected after the base unit 4 is activated by the slave unit 1. , so that the operating voltage is continuously transmitted from the base unit 4 to the slave unit 1, thereby enabling continuous communication between the base unit 4 and the slave unit 1.

Here, as shown in FIG. 3 (a), the base unit 4fftl includes a tone signal generation circuit 40 that generates a tone signal of, for example, about 20 KHz, which is out of the call voice signal band.When the handset 8 is off-hook, " The off-hook signal OF of ``o'' is sent to the transistor Q.

The switch circuit 41 turns on the transistor Q and passes the 1.-on signal by inputting it to the base of the switch circuit 1i'841. A mixer 6 circuit 42 mixes and agitates the call voice signal TS from the side, and a carrier wave (
For example, an FM modulation circuit 43 is provided which transmits off-hook information by FM modulating a frequency (6.5 MHz) and transmitting off-hook information together with a call voice signal. p is transported as shown.
FM demodulation circuit 48 using general-purpose FM reception 19J for M modulated waves, and using [for example AN7223 (model name)] 47 for tuning ■
a bypass filter 49 that passes only the tone signal from the signal demodulated by the FM demodulation circuit 48;
A general-purpose tone decoder IC [for example, N, JM5] decodes the signal passing through the bypass filter 49.
67 (model name)] 1-1 decoder circuit 51 using 50
and a comparison circuit 52 that is turned on by this decoded output and outputs an off-hook signal detection signal (by doing so, in the embodiment, the off-hook of the handset 8 of the base unit 4 is detected by the base unit operation detection unit 26). It looks like this.

Of course, as shown in FIG. 4(a), an off-hook signal generation circuit 53 consisting of a Colpitts oscillator circuit that operates when an off-hook signal OF is manually applied to the base unit 4 side is used to generate, for example, an @image signal, a call, etc. when the handset 8 is off-hook. Another ll12 transmission frequency other than the audio signal carrier, e.g. 10.7 M
A signal of 10.7 MHz is generated and transmitted, and a signal of 10.7 MHz is transmitted on the main unit operation detection unit 26 side as shown in FIG. 4(b).
A reception amplification circuit 2854 that receives and amplifies the signal of
．． Off-hook of the handset 8 may be detected by reception of 10.7 MHz.

The block diagram of the relay adapter 22 shown in FIG.
However, the communication circuit from the base unit 4 to the slave unit 1, etc. is omitted because it is unnecessary for explaining the operation of the present invention. tl! 4. The configuration of the handset 1 is basically the same as the circuit shown in FIG. 5, but the configuration relating to the call notification method is different, so the explanation will be omitted here.

Further, the outputs A to C and X of the base unit operation detection unit 26 . . . in FIG. 2 correspond to the inputs A to C and X of the base unit selection unit 25.

FIG. 5 shows a circuit of an embodiment in which two slave units 1 and two parent units A4 are combined, and in this circuit, the transmission line 31. Parent device connection line 293, relay contact ra1 of parent device selection section 25. Normally closed side NC of rbl, connection wire 27,
The slave unit 11.1.
A standby voltage is applied to and supplied to the

The handset selector 23 applies standby voltage to the handset 11 through relay contacts rc and rd (NC), and applies a resistor connected in parallel to the No side of the beam 1/- contact rc to the handset 12. A standby voltage is applied via a resistor connected to the NC side of relay contact rb. This waiting child 4!1
．． ．． , 1□ are high impedance and the flowing current is extremely small, so the transmission h3. ', 32' The voltage at E is set as the standby voltage and is not affected by the presence of a resistor.The connecting wire 27 connected to the relay contacts RAT, RB, RC, RD, etc. is equipped with a DC cut circuit. &'334.34
buffer amplifier section 30 via removal filter 33.
The input terminal of the buffer amplifier section 30 is connected to the input terminal 1-, and the dummy load section 32 is connected to the output terminal of the buffer amplifier section 30.

Main unit 4. is the transmission II 3, and the base unit connection line 2 (), and the NC side of the l/- contact ra and the 1/- contact r.
Connect between j7 and 1/- contact ra on the NC side of b1
The No side of relay 2 is connected between the No side l/- contact 1'12, and the base unit 42 is connected to the No side of the relay - contact ra via the transmission line 32 and the base unit connection line 29°. b-contact r b
; J: f: Connect between the NC side of relay contact r a, 2 and the NC side of relay contact b2. 1/-contact r a 2 , r
Both ends of the dummy load section 10 are connected between the common terminals b2.

In addition, each parent unit connection line 291, 292 has X, X, 'Y',
Parent device connection detection units 261 and 262 are connected as shown by the arrow Y, and the parent unit connection detection units 26. .

The detection output of 26□ is input to the logic circuit of the parent device selection section 25. This logic circuit is, for example, the parent device connection detection section 26.
．． If the detection output of is 'H'', transistor Q is turned on through OR gate 35 to drive relay RYa, and its relay contact rat is turned on.

Switch rd2 from the NC side to the No side. In addition, the detection output of the base unit connection detection unit 261 is “Yes”, and the base unit connection detection unit 261
If the detection output of 62 is "H", the transistor Q2 is turned on through the AND gate 36 to drive the relay RYb, and the relay contacts rb, rb2 are switched from NC (Itll to No side). If both detection outputs are I-”, INV gate 37.38
The 0-car detection unit 26. turns on the transistor Q through the three AND gates and the OR gate 35 to drive the relay RYa, and switches the relay contacts r a l and r a2 from the NC side to the NC side. , 262 are both "H", the transistor Q is turned on through the OR gate 35 to drive the relay RYa, and the relay contacts ra, , ra2 are switched from NC@ to the NC side.

On the other hand, the slave unit connection line 28. , 28z each have a slave unit connection detection unit 24. ．． 242 is connected, and the handset 11 or 12
If the standby voltage drops due to the calling operation, the handset connection detection unit 241 or 242 detects this and drives the relay RYc or RYd to connect the relay contact rc or r.
d from the NC side to N.

It is designed to switch to the side.

In this way, in the circuit of FIG. 3, one master unit 4. or 42 is the relay contact ra1. of the base unit selection unit 25. rb.

, the other base unit 42 or 41 is connected to the connection line 27 through the relay contact
a,, is connected to the dummy load unit 32 through rb2, and the buffer amplifier unit 30 is connected to the parent units 4+ and 42.
, the dummy load section 32, and the switching section 31 are shared.

In each of the above embodiments, the dummy load section 32 is composed of a circuit having a resistance value corresponding to the power consumption capacity of the slave unit, but the resistance value may be made infinite, that is, open. , it is assumed that switching between this resistance value and infinity is performed as appropriate.

Also, the standby voltage and the operating voltage are set to the same voltage, and the slave unit 1
Of course, the current value or the time period for flowing the current may be different between standby and operation.

Furthermore, the standby voltage may be applied from the relay adapter 22, and the relay adapter 22 may of course be incorporated into the slave unit 1 or the base unit 2.

[Effects of the Invention] According to the present invention, a slave unit equipped with a monitor TV camera, a base unit equipped with a monitor TV, and a base unit and slave unit are connected, and video signals from the slave unit and the base unit and the base unit are connected. It consists of a two-wire transmission line that transmits call audio signals between slave units, and during standby, a constant standby voltage is supplied to the slave unit via the transmission line, and when the slave unit's calling means is operated, the caller can call the base unit. At the time of a call, the standby voltage value is instantaneously changed in conjunction with the operation of the calling means of the slave unit, and this change notifies the base unit of the call, and also transfers the activation operation from the base unit to the slave unit in response to the call from the slave unit. A two-wire television intercom system that supplies operating voltage for a certain period of time via a transmission line, comprising one or more base units and one or more slave units, each of which has at least a plurality of slave units; A relay adapter is provided between the base unit and the slave unit, and each relay adapter is provided corresponding to each slave unit to be connected, and is controlled by detecting changes in standby voltage for the corresponding slave units. a handset operation detection section that generates an output, and a handset selection section that enables transmission of operating voltage and signal to the handset that receives a calling operation based on the output of the handset operation detection section;
A base unit operation detection unit is provided corresponding to each base unit and detects off-hook information of the handset of the base unit transmitted through the transmission line, and detects the base unit during a call based on the detection output of the base unit operation detection unit. a base unit selection unit that selects and at least enables transmission of an operating voltage from the base unit to the slave unit; a buffer amplifier unit that unidirectionally transmits a signal from the slave unit to the base unit; and an operating voltage to be transmitted. a dummy load section that absorbs
The dummy load unit is equipped with a switching unit that controls the connection between the base unit and the base unit. Therefore, even if there are multiple base units, a call from the slave unit can be transmitted to each base unit. It can detect call activity, and as a result connects the base unit and slave unit on a one-to-one basis.S: Basic 2-wire TV interface.
Using the main system dem, construct a multi-station system such as one base unit and multiple -f machines, multiple base units and one slave machine, or multiple base units and multiple slave units. It has the effect of being able to

Further (the kneeling invention of Claim J is provided with a plurality of base units6)1
．． : If the standby voltage can be transmitted only by the base unit set at the initial stage, and whether it is 1 or 2, the standby voltage can be transmitted by the base unit that is transmitting the standby voltage by the initial setting, regardless of which base unit is in the call state. At the same time, the operating voltage can be continuously transmitted from the base unit in the talking state without causing a collision of transmitted voltages, and as a result, as long as the base unit in the talking state takes the handset off-hook, the relevant When the base unit is selected, the operating voltage is continuously transmitted to the 'f unit, and the slave unit is continuously operated, thereby making it possible to function the TV intercom.

Mano:: In the invention described in claim 3, the circuit count of the buffer amplifier section, dummy D-domain section, and switching section is shared between the two base units.11. This has the effect of simplifying the circuit.

In the invention of claim 5, since the standby voltage is transmitted to one unit by the relay adapter, there is no need to transmit the standby voltage from the base unit, and therefore the transmission setting is not required at the initial stage. be,

[Brief Description of the Drawings] Fig. 1 is a block diagram showing a schematic configuration of one embodiment of the present invention, Fig. 2 is a detailed block diagram thereof, and Fig. 3 is a circuit diagram of another embodiment of the present invention. , 3rd ['A (a) is a circuit diagram of the transmission means of off-hook information of the handset of the base unit used in the same-F, and Figure 3 ([)] is a circuit diagram of the operation detection unit of the base unit used in both cases. , Fig. 4(a) shows the handset 1- of the master unit used in the above.
A circuit diagram of another example of off-hook information transmission means, Fig. 4 (
b) is a circuit diagram of another example of the base unit operation detection unit used in the same 1, FIG. 5 is a circuit diagram of another embodiment of the present invention, and FIG. 6 is a schematic configuration diagram that is the basis of the present invention Figure 7 is the same block diagram as above,
FIG. 8 is an explanatory diagram of the frequency arrangement of signals transmitted through the same transmission line. 1 is the slave unit, 2 is the push button, 3,3゛ is the transmission line, 4 is the main unit, 8
is a handset, 22 is a relay adapter, 23 is a handset selection unit, 24 is a handset operation detection unit, 25 is a base unit selection unit, 26 is a base unit operation detection unit, 27 is a connection line, 28 is a slave unit connection line, 2
9 is a main unit connection line, 30 is a buffer amplifier section, 31 is a switching section, and 32 is a dummy port/domain section. Agent Patent Attorney Ishi 1) Chief 71 is the handset 2, push button 33 is the transmission line, 4 is the main unit 4, Figure C0) Voluntary action to amend Figure 8 procedure to (b)) July 1999 288

Claims (8)

[Claims] (1) Connect a slave unit equipped with a TV monitor camera, a base unit equipped with a TV monitor, and the base unit and slave unit to receive video signals from the slave unit and voice signals from calls between the base unit and the slave unit. During standby, a constant standby voltage is supplied to the handset via the transmission line, and when a call is made to the base unit by operating the calling means of the handset, the above standby voltage value is supplied to the slave unit through the transmission line. The voltage changes instantaneously in conjunction with the operation of the calling means of the slave unit, and this change notifies the base unit of the call, and also transmits the operating voltage from the base unit to the slave unit when activated in response to a call from the slave unit. A two-wire television intercom system that supplies power for a certain period of time through A relay adapter is provided between the relay adapters, and each relay adapter is provided corresponding to each slave unit to be connected, and a slave unit operation detection device that detects a change in standby voltage to the corresponding slave unit and generates a control output. a slave unit selection unit that enables the transmission of an operating voltage and a signal to a slave unit that has received a calling operation based on the output of the slave unit operation detection unit; A base unit operation detection unit that detects off-hook information of the handset of the base unit transmitted through a transmission line, and a base unit that selects the base unit that is currently on a call based on the detection output of the base unit operation detection unit, and operates from the base unit to the slave unit. a base unit selection unit that enables at least transmission of operating voltage; a buffer amplifier unit that transmits a signal from the slave unit to the base unit in one direction; a dummy load unit that absorbs the operating voltage to be transmitted; and the dummy load unit. A two-wire television intercom system characterized by comprising a switching section for controlling connection between a main unit and a base unit. (2) A standby voltage is transmitted from the master unit, which is initialized in advance to be disconnected from the dummy load unit by the switching unit during standby, to each slave unit via the master unit selection unit and the slave unit selection unit, and The standby voltage from another base unit is connected to the dummy load unit by the switching unit, and the slave unit selection unit is controlled by the detection output of the slave unit operation detection unit that corresponds to a call from any slave unit to perform the call operation. It is possible to supply voltage during operation only to the handset selected by the handset, and in response to the calling operation of the handset, the change in standby voltage is transmitted through the handset selection section and the base selection section, and the change in standby voltage is transmitted between the handset selection section and the buffer. A change in the standby voltage is transmitted to the remaining master units through the amplifier section, the dummy load unit, and the switching unit, so that all the master units are activated and the operating voltage can be supplied from each base unit, Each base unit operation detection unit corresponding to each base unit detects a base unit that has stopped outputting the operating voltage within a certain period of time, and connects the detected base unit to the dummy load unit via the switching unit. The master unit that is still supplying operating voltage after a certain period of time is separated from the dummy load unit by the switching unit, and connected to the master unit selection unit, and the operating voltage supplied from the master unit is connected to the master unit selection unit. 2. The two-wire television intercom system according to claim 1, wherein the signal is supplied to the handset that has received a call operation through the handset selector and the handset selector. (3) Two base units are provided, and when one of the two base units is connected to the base unit selection unit, the other base unit is always connected to the dummy load unit via the switching unit, 2. The two-wire television intercom system according to claim 1, wherein the buffer amplifier section, the dummy load section, and the switching section are shared by two base units. (4) The voltage during standby and the voltage during operation are equal in value, but the current value or the time during which the current continues to flow during standby and operation is different.
Wire TV intercom system. (5) During standby, the relay adapter and base unit are separated, and the standby voltage is transmitted from the relay adapter to the slave unit, and when there is a call operation on the slave unit, the relay adapter and base unit are connected. 2. The two-wire television intercom system according to claim 1. (6) The two-wire television intercom system according to claim 1, wherein off-hook information of the handset of the base unit is transmitted from the base unit to the relay adapter at a frequency other than that of a video signal or an audio signal. (7) The two-wire television intercom system according to claim 1, wherein off-hook information of the handset of the base unit is multiplexed into an audio signal transmitted from the base unit to the slave unit and transmitted to the relay adapter. (8) At the time of initial setting, the slave unit and the relay adapter are connected, and the relay adapter and the base unit are separated and separated, and the standby voltage is transmitted from the relay adapter to the slave unit during standby, and the relay adapter is connected to the slave unit. 2. The two-wire television intercom system according to claim 1, wherein the relay adapter and the base unit are connected when the slave unit operation detection unit detects the calling operation.