JPH02266742A - Two-wire type television interphone system for multiple dwelling house - Google Patents

Abstract

PURPOSE:To construct an interphone system for multiple dwelling house in which the feature of a two-wire type television interphone system which becomes a fundamental can be utilized by using a required number of master machines, a relay adaptor, and a slave machine on which a call means is attached. CONSTITUTION:When a call button, for example, the call button 22 corresponding to the master machine 42 out of the call buttons 2 of the call signal generation circuit 17' of the slave machine 1 is operated, the call signal generation circuit 17' generates a call signal in which the master machine 42 is designated. The call signal is received by the call circuit 41 of the relay adaptor, and a master machine selection part 25 transmits the call to the master machine 42 by decreasing a standby voltage supplied from the master machine 42, and the master machine 42 is started up reacting according to the reduction of the voltage. In such a manner, the system for the multiple dwelling house can be constructed by using the two-wire type television interphone system which becomes the fundamental.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a 26-type television intercom system for multi-channel housing for residential complexes.

[Conventional technology] In order to make it possible to see guests indoors, a monitor TV camera is installed on the handset installed at the entrance, and a TV monitor is installed on the base unit installed indoors for calls. At the same time, a television intercom system capable of displaying images captured by a monitor television camera has been developed and used.

As shown in Figure 4, the TV intercom system is set up at the front door, etc., and when a child who is 80 years old presses the call button 2 on R1, it is set up inside the room via the transmission line 3. The calling signal is transmitted to the base unit 4, the ejection sound is output from the screen 5 provided on the base unit 4, power is supplied to the monitor TV camera 6 of the slave unit 1, and the monitor data is output. 1/
The video signal of the camera 6 is transmitted to the base unit 4 through the two-wire transmission line 3.
The video is displayed on a monitor television 7, and the resident can pick up a handset 8 and answer the call to make a call.

Figure 5 shows the circuit block of the television intercom system shown in Figure 4. It is configured by combining a slave unit 1 with a camera 6, etc., and both the master unit 4 and slave unit (N1) are connected by a transmission line 3, and the master unit 4 and the slave unit (N1) are connected by a transmission line 3.

Power is supplied from unit 4 to slave unit 1 through transmission line 3,
Also, @
Necessary information can be communicated by multiplex transmission 1- of image signals, calling signals, or voice signals between the four base units and the four slave units 1.

To explain in more detail, the base unit 4 includes an electric/S superimposing circuit 9 for supplying power to the handset 1, a modulation unit 10 that modulates a high frequency signal based on a voice signal from the handset 8, and 5 from the handset 1 side. A demodulating section 11 demodulates the transmitted modulated signal and extracts a call audio signal; a video signal receiving section 12 receives the video signal transmitted from the handset 1 and outputs it to the monitor television 7; A call detection unit 13 that receives a call signal sent from the side and generates a signal for ringing the speaker is interposed between the above circuit group and the transmission line 3 to balance the unbalanced signals of the circuit group L. The circuit includes a balancing circuit 14 that performs equalization, and a short-circuit protection circuit 45. The modulation unit 10 inputs the call voice signal from the handset 8 to the modulation circuit 1.0a, and
A high frequency carrier wave f, which is a carrier wave of
The demodulation unit 11 includes a bandpass filter 11a that limits the frequency band of the modulated signal from the balancing circuit 14, a demodulation circuit 111 that demodulates the modulated signal, and an audio signal. It has an amplifier circuit 11c, and is configured to output the call voice of the handset 1 from the hand cell +-S by outputting a call voice signal from the voice signal amplification circuit 11C.

On the other hand, the handset] 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 base unit 4 via the transmission line 3, and the microphone 1.
, 6), and the base unit 4f! The modulated signal sent from If'! W, a demodulator 1 that modulates and extracts a call audio signal;
8, a video system circuit that sends the video signal from the monitor TV/video camera 6 to the base unit 4 side through the video filter circuit 19, and a call f3 that notifies the base unit 41T1 of a call by operating the call button 2. The signal generating circuit 19 is provided with a balancing circuit 20 that is interposed between the transmission line 3 and the circuit group 1 to balance the unbalanced signal of the circuit group 1, and a polarization circuit 44. There is. The modulation section 17 receives an output 13 from a microphone signal amplification circuit 17a that amplifies the microphone signal to a certain level of 1/bell.
signal is input to the modulation circuit 17b, and the second general transmission wave (base unit 4
The configuration is such that the high-frequency carrier wave f2, which is a high-frequency carrier wave that can be distinguished from the first carrier wave f on the side, is modulated and sent out through the band-pass filter 17c,
The demodulation section 18 includes a bandpass filter 18a that limits the frequency band of the modulated signal from the balancing circuit 20, a demodulation circuit 18b for demodulating this modulated signal, and an audio signal amplification circuit 18c. , audio signal amplification circuit 18c
From the speaker 21 to the base unit 4 by outputting a notification audio signal from the
It is configured to output a notification sound from the side.

The power separation unit 15 also includes a power separation circuit 15a that separates the power from the multiplexed signal sent from the main unit 4 (1 m), and a power separation circuit 15a that detects a significant change in the power output value from the power separation circuit 15a and detects a significant change in the power output value from the power separation circuit 15a and detects a significant change in the power output value from the power separation circuit 15a. 6, and a shunt regulator 15c to keep the supplied power current constant.

The base unit 4 and the slave unit 1 have connection terminals T,, T,' provided on the base unit 4 side, and connection terminals T2, ., T,' provided on the slave unit 1 side.
T2° are each connected by a transmission line 3 made of parallel electric wires, etc.
As mentioned above, in addition to the power supply, video signals, call audio signals, and calling signals necessary for information communication are multiplex transmitted between the base unit 4 and the slave unit 1 via the transmission line 3.

By the way, in the intercom system having the above-mentioned configuration, when the call button 2 of the handset 1 is operated, the call signal generation circuit 4
6 and outputs a calling signal.

This calling signal is sent to the base unit 4 side via the balancing circuit 20, the non-polarization circuit 44, and the transmission line 3, and is applied to the call detection unit 13 via the balancing circuit 14 of the base unit 4, and the calling signal is As a result, the speaker 5 of the parent EL 14 is made to sound.

On the side of the base unit 4 that has been called in this way, the speaker 5 sounds and the superimposed voltage value to the power supply superimposition circuit 9 is changed to the slave unit 1 (
This constant current output is switched from the standby voltage value required for the calling operation of the Ill to the operating dark voltage value required to supply power to the monitor television camera 6, and supplies constant current to the slave unit 1. In the handset 1, the power is separated and outputted by the power separation circuit 15a to activate the camera power switch 15b, and the monitor TV camera 6 is output through the shunt regulator 15c.
and drives the monitor television camera 6.

When the monitor television camera 6 is driven, the video signal is transmitted from the video filter circuit 19 to the balancing circuit 20 and then to the balancing circuit 14 on the parent aI 14 side via the transmission line 3, passes through the video signal receiving section 12, and is transmitted to the monitor. The image will be sent to the television 7 and displayed on the monitor television 7.

The call voice signal from the handset 8 is FM-modulated by a modulation circuit 10a having a first carrier wave f, and this FM-modulated first carrier wave f.

is transmitted from the bandpass filter 10b to the handset 1 side via the balancing circuit 14 and the transmission line 3.

On the other hand, in the handset 1 receiving the signal of the carrier wave f, the modulated wave is inputted to the demodulation circuit 18b via the depolarization circuit 44, the balancing circuit 20, and the bandpass filter 18a of the demodulation section 18, and the modulated wave is inputted to the demodulation circuit 18b. The modulated wave of the carrier wave f1 is FM demodulated to obtain a speech audio signal output. Subsequently, this call audio signal is amplified by the audio signal amplification circuit 18c, and the call audio from the base unit 4 is outputted from the speaker 21 of the handset 1.

In addition, the call voice signal input from the microphone 16 on the handset 1 side is amplified by the microphone signal amplification circuit 17a, and is then amplified by the modulation circuit 17.
b, where the second carrier wave f2 is FM modulated,
It is sent from the bandpass filter 17c to the demodulation section 11 via the non-polarization circuit 44, the balancing circuit 20, the transmission line 3, and further through the balancing circuit 14 on the base unit 4 side.
After being demodulated by the voice signal amplification circuit 11c, the voice signal is amplified by the voice signal amplification circuit 11c, and the telephone voice is output from the handset 8 of the main unit 4.

Here, in such a television intercom system 11, the first carrier wave f and the second carrier wave f2 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. 6 is a diagram showing the relationship between the frequencies of these signals,
A direct current power supply voltage DC, a video signal V having a frequency band of several MHz, and a first carrier wave f at a frequency above that,
The modulated wave 21 from the base unit 4 and the second carrier wave 2
Therefore, the modulated waves from the handset 1 are set to different frequencies 't1, and these signals are multiplexed and transmitted through the transmission line 3.

Problem M1 that the invention U attempts to solve In the section M1, the conventional system described in F has a base unit 4 and a slave unit 1.
This is a one-to-one system, but it uses a configuration in which the standby voltage and operating dark voltage are switched in response to a call from the handset.
The present invention was made in view of two problems, and the present invention was made in view of two problems. [Means for Solving the Problems] The present invention aims to provide a two-wire TV intercom system for apartment buildings constructed using a TV intercom system. A cordless handset is equipped with a monitor TV/Video. g! It consists of a two-wire transmission line that connects the base unit and slave unit, and transmits video signals from the slave unit and voice signals between the base unit and the slave unit, and has a constant standby voltage during standby. is supplied to the slave unit via a transmission line, and when the slave unit discharges to the master unit by operating the calling means of the slave unit, the above-mentioned standby voltage value is instantaneously changed in conjunction with the operation of the discharge means of the slave unit, and this change causes the parent unit to A two-wire television ink-phone system that notifies the machine of a call and simultaneously supplies operating dark voltage from the m machine activated in response to discharge from the slave machine to the slave machine at a fixed time via a transmission line. ,,m installed in each dwelling unit
At least one handset installed in a common use area such as a joint building, and a relay adapter interposed between each base unit and the slave unit. A calling means that generates a corresponding calling signal is provided, and the relay adapter has a function of transmitting standby voltage to the slave unit, and selects and discharges the corresponding master unit according to the operation of the discharge means of the slave unit. :
A device that changes the voltage between the lines of the transmission line of the base unit, etc., receives the operating dark voltage output from the base unit after the base unit is activated, and sends it to the slave unit via the transmission line. a base unit selection unit having a function of transmitting operating dark voltage, etc., and detecting the operation of the selected base unit based on the operating dark voltage, and not accepting a call signal from the slave unit until the operation of the base unit is completed. In this way, we were able to explain the base unit operation detection unit that sets the base unit selection unit.

The invention according to claim 2 is the invention according to claim 1, in which the standby voltage output from the master unit during standby is transmitted to the slave unit through the master unit selection section of the relay adapter.

The invention according to claim 3 is the invention according to claim 1, in which the slave device is provided with a power supply separation section that obtains power from the voltage transmitted through the transmission line, and the output point of the power switch inserted in the output system of the power supply separation section is provided. A voltage signal for detecting the operation of the base unit is extracted from the relay adapter to the base unit operation detection section of the relay adapter.

According to a fourth aspect of the present invention, in the first aspect of the present invention, during standby, the standby voltage is transmitted to the slave unit only by the relay adapter, and the standby voltage from the master unit is cut off.

[Function] According to the present invention, the basic two-wire television intercom system, which connects a base unit and a slave unit on a one-to-one basis, can be transformed into a set consisting of a plurality of MAs, including at least one slave unit, using a relay adapter. It is possible to build a residential system 11. In other words, when you operate the calling means provided on the slave unit to call a specified base unit, the relay adapter connects to the base unit.
The call is transmitted to the base unit by changing the line voltage of the two transmission lines, the J11 is activated, and the activation operation transmits the operating dark voltage to the slave unit. In this case, the operating dark voltage is determined by transmitting the operating dark voltage from the parent unit via the parent unit selection unit.1. In addition, the relay adapter that receives the operating dark voltage from the parent unit may independently transmit the operating dark voltage from the built-in power supply through the parent unit selection section.8 Also, the standby voltage may be transmitted to the slave units. The standby voltage output from each base unit can also be transmitted to the slave unit via the base unit selection section, or the standby voltage can be obtained from the built-in power supply connected to the relay adapter and transmitted to the slave unit. Like 1. 6 Now, it is called 14 = The activation operation of the base unit is detected by the base unit operation detection unit, and the calling operation of the calling means is not accepted until the call between the base unit and the slave unit is terminated, and the call operation is not accepted between the base unit and the slave unit. The connection state with the parent device will be maintained.

In this way, any base unit can be called by the calling operation of the calling means on the handset side, and an intercom system for apartment buildings can be constructed by simply adding a relay adapter to a conventional two-wire TV intercom system. This is possible.

[Example] The present invention will be explained below with reference to Examples.

FIG. 1 shows a block diagram of an embodiment of the present invention, in which a handset 1 is installed at a common use place such as a common entrance, and a transmission line 3
The base units 4 provided in each dwelling unit are connected to the relay adapter 22 via transmission lines 3. In the embodiment, the relay adapter 22 is built into the main body of the handset 1, but it may of course be installed separately.

FIG. 2 shows a concrete block diagram of the embodiment, and the handset 1, like the handset 1 shown in FIG. A speaker 21 for audio output, a power supply separation section 15, a balancing circuit 20, a video filter circuit 19 inserted between the monitor television camera 6 and the balancing circuit 20, and a speaker 2.
a demodulating section 18 interposed between the microphone 16 and the balancing circuit 20; and a modulating section 17 interposed between the microphone 16 and the balancing circuit 20.
and a power separation section 15 consisting of a power separation circuit 15a, a power switch 15b, and a shunt regulator 15c, and a main unit 41 provided corresponding to each dwelling unit.
have call buttons 2... corresponding to each one, and when these call buttons 21... are operated, the operated call buttons 21...
. . . and generates a calling signal to call the base unit 41 corresponding to the calling button 21 .

The relay adapter 22 transmits the non-polarizing circuit 401... corresponding to the transmission line 31... connecting each base unit 4I..., the balancing circuit 421..., and each base unit 41... Line 3.
. . . non-polarizing circuit 401 . . . and balancing circuit 42 .・
. . , and also connect the transmission line 3° from the handset 1 to connect the handset 1 and each base device 4. . . . Output from the power source separation section 15 when the operating dark voltage is supplied to the base device selection section 25, which has a function of selectively controlling the connection between the two, and the power source separation section 15 of the child device 1. By inputting the voltage signal, the main unit 4. ... and provides the detection output to the parent device selection section 25;
The base unit 4 is called upon receiving the call signal from the call signal generation circuit 17° of the slave unit 1. . . . is provided.

During standby, the standby voltage is output from each parent FI4+ to the relay adapter 22 through the transmission line 31..., and the parent device selection section 25 of the relay adapter 22 outputs the standby voltage from each parent FI4+ to the slave device through the Mt device selection section 25 and the transmission line 3°. A standby voltage is supplied to 1. child f
In IT, since the voltage supplied through the transmission line 3' is the standby voltage, the voltage at the output point of the power switch 15b of the power supply separation section 15 becomes a low voltage, and this voltage signal is transmitted to the in operation detection section 26 of the relay adapter 22. Upon receiving this voltage signal, the base unit operation detection unit 26 determines that the base units 41 . Set the base unit so that it can accept calls from the base unit.

Now, when the call button 2 of the call signal generation circuit 17° of the slave unit 1 is operated, for example, the call button 22 corresponding to the base unit 42 is operated, the discharge signal generation circuit is linked to the operation of this call button 22. 1
7' generates a calling signal specifying the base unit 42. This calling signal is received by the calling circuit 41 of the relay adapter 22, and the calling circuit 41 transmits to the parent device selection section 25 that the parent device 42 has been called. The main unit 42 is set to be connected to the main unit 42 with low loss through the main unit selection unit 25, and the standby voltage supplied from the main unit FI4+ is forcibly lowered as appropriate to detect that there is a call to the main unit 42. introduce. The FA machine 4□ starts up in response to this voltage drop, outputs the operating dark voltage to the relay adapter 22 through the transmission line 3, and connects the relay adapter 22 and the transmission line 3°.
In the slave unit 1, which supplies an operating voltage to the slave unit 1 through 6, the power supply separation unit 1.5 generates a voltage signal higher than the output point of the power switch 15b in response to the supply of this operating voltage,
The information is transmitted to the base unit operation detection unit 26 of the relay adapter 22.

The base unit operation detection unit 26 that has input this voltage signal gives a base unit operation detection output to the base unit selection unit 25, and while this detection output is being input, the base unit selection unit 25 selects the called base unit 42, It maintains the connection state with the handset 1 to enable transmission of video signals and voice signals, and functions as a two-wire telephone/video interponder. This operation is the main unit 4. is held if handset 8 is off-hook;
When the phone call ends and the phone goes on-hook (or after a certain period of time, for example, 3 minutes), the base unit 42 switches the output voltage to the standby voltage. Due to this switching, the voltage supplied to the handset 1 becomes the standby voltage, and therefore: the voltage at the output point of the power switch 15b of the power separation unit 15 of the r-device 1 becomes a low voltage, and this voltage signal is transmitted to the relay adapter 22. The voltage signal is sent to the base unit operation detection unit 26, and the base unit operation detection unit 26, which receives this voltage signal, determines that the base unit 4I... is in a non-activated state and gives a signal to reset the base unit selection unit 25, and restores the original state. ν in standby state
zu, ′: becomes.

FIG. 3 shows a concrete circuit of the power source unit 15, the ejection signal generation circuit 17°, and the relay block 22 of the slave unit 1 of the above embodiment, and the power supply separation unit 15 connects the power switch 15b to a transistor. The m-vibration motion detection section 2 of the relay adapter 22 is
6 to output a voltage signal.

The call signal generation circuit 17° is connected to the call button 2. . . . When the corresponding call button 21 .

These signals are connected to the corresponding transistors Q, .
, these 1-transistors Q,
. . . is provided in the m machine selection unit 25 and controls the base current of the transistor Q, . Bypassing the base current of the corresponding l-transistor QII...
+... is turned off, latching relay RY,...
Set so that no excitation current flows through the on-drive coils CL a , . Also, each transistor Q...
The collector of ・ is connected to the base of the transistor Q6 for voltage forced drop control via a diode OR, and when any call button 21... is operated, the corresponding transistor Q1... is turned off. Then, the transistor Q0 is turned on and the voltage of the transmission line 3' connected to the handset 1 is lowered for a certain period of time.

The tf master unit selection unit 25 selects each latching ring l/RYI/
. . . Glue l/- contact r 1 . . . in each balancing circuit 42 . One end and transmission! 13', and in parallel to each relay contact r,... and a resistor ■3.1... and a diode D... which series circuit is connected. When on standby, the main unit 4. The standby voltage from ... is supplied to the handset 1 side through the series circuit with the resistor Fjl... and the diode I)l..., and when the call button 21... is turned on, 5 is activated. The corresponding transistor Q,... is turned off, and due to this turning off, the corresponding transistor Q... is turned on, which turns on the latching relay RYl... and so on! /- Contact r,... is turned on, and resistor R1... and diode D,...
・Which series circuit is shorted, and this short circuit forms a low-loss circuit. The above transistor Q is linked to the operation of the call trI21... through this low loss circuit.
.

The voltage drop due to the turning off of the main unit 41 is transmitted to the selected FA machine 41... Also, after the main unit 41... is started, the main unit 4. ..., the special operating voltage is supplied, and the voltage signal from the power supply separation section 15 becomes "
H”, the parent unit operation detection unit 26 detects the transistor Q.
21... turns on and shorts the base circuits of the transistors Q,..., and calls after starting the master device 41..., 102. The latching relays RY, . . . are set so that they are not turned on even if . )1113
I transistor Q for iI. The latching relays RY, .・The voltage signal from the power supply separation unit 15 becomes “L” after the end of the call.
Therefore, by turning off the transistor Q21... and turning on the call button 21..., the transistor Q +
+... is returned to the standby state in which it is possible to turn on the transistors Q20, while the transistors Q20 are turned off. , transistor Q31... is turned on, and latching relay RY is turned on.
, . . . are turned off and returned to a standby state.

In the above embodiment, the power switch 15b of the power separation unit 15 provided in the slave unit 1 is used as an input to the base unit operation detection unit 26.
However, when the relay adapter 22 is placed separately from the slave device 1, the transmission line 3. which connects the base device 1 and the relay adapter 22 is used. ... may be directly detected.

In addition, in the present invention, the power supply for the handset 1 and the relay adapter 22 may be supplied from the base unit 41, or separate power sources may be provided for the handset 1 and the relay adapter 22. In the invention, the main unit 4. ...from slave unit 1 to base unit 4.・
It is sufficient if the voltage for identifying whether the device is in a standby state or an operating state is transmitted separately as a standby voltage and an operating special voltage.

In addition to the method of outputting the calling signal based on the operation of the calling button 21 separately from the calling signal generating circuit 17' to the calling circuit 41 of the relay adapter 22 as in the circuit shown in FIG.
The signal may be transmitted to the paging circuit 41 using a time division multiplex transmission type signal. The relay adapter 22 also includes a balancing circuit 40. . . . and a non-polarization circuit 421 . The order is not particularly limited to the examples. [Effects of the Invention] The present invention provides a two-wire television intercom system that includes:
It consists of a base unit installed in each residential unit, at least one slave unit installed in a common use area such as a common entrance, and a relay adapter interposed between each base unit and the slave unit. A calling means is provided to generate a calling signal corresponding to the base unit of each dwelling unit, and the relay adapter has a function to transmit standby voltage to the slave unit, and selects the corresponding base unit according to the operation of the call means of the slave unit. The function changes the line-to-line voltage of the transmission line of the base unit selected for calling, and receives the operating special voltage output from the base unit after starting the base unit selected for calling, and sends it to the slave unit via the transmission line. a base unit selection unit having a function of transmitting an operating special voltage;
The base unit operation detecting unit detects the operation of the base unit selected for calling based on the operating special voltage and sets the base unit selection unit so as not to accept the calling signal of the slave unit until the operation of the base unit is completed. , any base unit can be called by the calling operation of the calling means on the handset side.Based on the conventional two-wire TV intercom system, it uses the necessary number of base units and relay adapters. The present invention has the effect that it is possible to construct an intercom system for apartment buildings that takes advantage of the features of the basic two-wire television intercom system by simply using a handset equipped with a calling means.

[Brief explanation of drawings]

Fig. 1 is an overall schematic block diagram of an embodiment of the present invention, Fig. 2 is a detailed block diagram of the integrated state of the handset and relay adapter used in the above, Fig. 3 is a specific circuit diagram of the same, and Fig. FIG. 4 is a block diagram of a two-wire television interbon system, FIG. 5 is a detailed block diagram of the same, and FIG. 6 is an explanatory diagram of frequency allocation of the multiplex transmission system. ■ is a slave unit, 21... is a call button, 31..., 3' is a transmission line, 341... is a base unit, 17' is a call signal generation circuit, 22 is a relay block, 25 is a base unit selection 26 is a base unit operation detection unit, and 41 is a calling circuit. Agent Patent Attorney Ishi 1) Long 786 ffz ff+

Claims (4)

[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 is supplied for a certain period of time via a main unit, a main unit installed in each dwelling unit, and at least one slave unit installed in a common use area such as a common entrance.
It consists of a relay adapter interposed between each base unit and the slave unit, and the slave unit is provided with a calling means that generates a calling signal corresponding to the base unit of each dwelling unit, and the relay adapter is configured to transmit the standby voltage to the slave unit. A function that selects the corresponding base unit according to the operation of the calling means of the slave unit and changes the voltage between the lines of the transmission line of the base unit that has been selected for calling, and a function that activates the base unit that has been selected for calling. A base unit selection unit that has a function of receiving the operating voltage outputted from the base unit later and transmitting the operating voltage to the slave unit via a transmission line; and a base unit operation detection unit that detects based on the base unit and sets the base unit selection unit so as not to accept a call signal from the slave unit until the operation of the base unit is completed. TV intercom system. (2) The two-wire TV intercom system for apartment complexes according to claim 1, characterized in that the standby voltage output from the base unit during standby is transmitted to the slave units through the base unit selection section of the relay adapter. (3) The slave device is equipped with a power separation section that obtains power from the voltage transmitted through the transmission line, and the output point of the power switch inserted in the output path of this power separation section is connected to the operation detection section of the relay adapter's main device. 2. The two-wire television intercom system for apartment complexes according to claim 1, wherein a voltage signal for detecting operation of the main unit is extracted. (4) The two-wire television intercom system for apartment complexes according to claim 1, characterized in that during standby, the standby voltage is transmitted to the handset only by a relay adapter and the standby voltage from the master unit is cut off.