JP2008034994A - Transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a mobile unit which cannot transmit data from being selected. <P>SOLUTION: A controller 17 of a base unit 1 periodically checks the existence (operating status) of camera mobile units 3A-3C and sub-base units 4A-4D by repetitiously sending a control signal containing check data, and receiving a control signal containing a response while sequentially polling IDs of individual camera mobile units 3A-3C and sub-base units 4A-4D at regular time intervals. When a monitor button or an extension line button is operated, the controller 17 of the base unit 1 eliminates buttons B4-B6 and B11-B14 corresponding to the camera mobile units 3A-3C and sub-base units 4A-4D assigned with the IDs which have been confirmed as absent from a video monitor selection screen G1 or an extension line selection screen G2, and does not display those buttons thereon. Consequently, the camera mobile units 3A-3C and sub-base units 4A-4D which cannot transmit data are prevented from being selected by mistake on the video monitor selection screen G1 or the extension line selection screen G2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission system in which a plurality of slave stations are connected to a master station via a transmission line, and data is transmitted between the master station and each slave station via the transmission line.

  As an example of this type of transmission system, there is an intercom system as described in Patent Document 1. Such an intercom system includes a master station (interphone master unit) installed in a dwelling unit and a call slave unit (door phone sub unit) installed outside a dwelling unit (for example, an outside entrance) and used by a visitor for a call with a dweller. ), A camera slave station (camera slave unit) installed outside the dwelling unit to capture the surveillance area, and a phone call with the interphone master unit installed inside the dwelling unit, and a door phone slave unit via the interphone master unit Consists of a plurality of slave stations including intercom substations (interphone secondary master units) for making calls between them, and the master station (interphone master unit) and telephone slave units (doorphone slave units and interphone secondary master units) The voice data is transmitted to and received from the mobile phone, and the video data transmitted from the camera slave station (camera slave unit) is displayed on the display device (liquid crystal display, etc.) of the master station (interphone master unit). Nina To have.

Here, when there are a plurality of camera slave stations that transmit video data and call slave stations that transmit and receive audio data, there is a display device that displays identification information corresponding to each slave station on a one-to-one basis. When the user performs an operation to select any of the slave stations based on the identification information, a command is transmitted to the selected slave station, for example, video data is transmitted to the camera slave station (camera slave unit) Command or a command to call the calling slave station (interphone sub-master) (command to cause the calling slave station to ring a ringing tone), etc., and video data or audio data is transmitted from the selected slave station based on the command. It is supposed to be transmitted.
JP 2004-135199 A

  By the way, in the conventional system as described above, even if any of the slave stations is intentionally stopped (powered off) or removed from the transmission line due to a system change, the identification information of all the slave stations is the parent information. Since it is displayed on the station display device, a slave station that is stopped or does not exist may be selected by mistake, and data is not transmitted from the selected slave station. There was a risk of being mistaken for a malfunction.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a transmission system that can prevent a slave station that cannot transmit data from being erroneously selected.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of slave stations are connected to the master station via a transmission line, and data is transmitted between the master station and each slave station via the transmission line. The master station is a display means for displaying at least one-to-one identification information corresponding to each slave station, and for selecting any slave station based on the identification information displayed on the display means. Operation input accepting means for accepting operation input, transmission control means for transmitting data to the selected slave station, and transmission check means for periodically transmitting data for operation confirmation to all slave stations And a display control means for preventing the display means from displaying identification information of a slave station that does not return a response to the operation confirmation data.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the transmission control means transmits the operation confirmation data by a polling method.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, in the first or second aspect, the slave station communicates voice data for a conversation between the master slave station and the camera slave station that transmits the video data captured by the imaging means. The master station sounds a sound based on the video control means for displaying the video data transmitted from the selected camera slave station on the display means and the voice data received from the selected call slave station. And a call means for converting the voice of the speaker into voice data and transmitting the voice data to the call slave station from the transmission control means.

  According to the first aspect of the present invention, the display control means of the master station periodically transmits data for operation confirmation from the transmission control means to all the slave stations and responds to the operation confirmation data. Since the identification information of the slave station that does not return is not displayed on the display means, the slave station that does not return a response to the operation confirmation data is deemed unable to transmit data, and the identification information of the slave station is not displayed on the display means. Incorrect selection can be prevented.

  According to the invention of claim 2, when a plurality of slave stations are connected to a common transmission line, it is possible to prevent the operation check data and the response from colliding with each other, thereby reducing the time required for the operation check. it can.

  According to the third aspect of the present invention, the interphone system having the effect of the first or second aspect of the present invention and comprising the master station, the camera slave station, and the communication slave station can be realized.

  Hereinafter, an embodiment in which the technical idea of the present invention is applied to an intercom system for a detached house will be described in detail with reference to the drawings.

  The intercom system according to the present embodiment includes an interphone master unit (hereinafter abbreviated as “master unit”) 1 installed in a dwelling unit, and a plurality of (three in the illustrated example) doorphone slave units installed outside the dwelling unit. 2A, 2B, and 2C, and a plurality of camera units 3A, 3B, and 3C that are installed outside the dwelling unit (in the illustrated example) and a plurality of units that are installed inside the dwelling unit (four in the illustrated example) Interphone sub-master (hereinafter abbreviated as "sub-master") 4A, 4B, 4C, 4D, door phone slave unit 2A and camera slave unit 3A are balanced two-wire transmission line Ls1 and master unit 1 The doorphone slave unit 2B and the camera slave unit 3B are connected to the master unit 1 via a balanced two-wire transmission line Ls2, and the doorphone slave unit 2C and the camera slave unit 3C are balanced two-wire transmission. It is connected to the master unit 1 via the line Ls3, and the sub master units 4A to 4D are balanced two-wire systems It is configured by connecting the feed to the main unit 1 by a transmission line Ls4. In the present embodiment, the master unit 1 corresponds to a master station, the camera slave units 3A to 3C correspond to camera slave stations, and the sub master units 4A to 4D correspond to call slave stations, respectively.

  Each of the doorphone sub-units 2A to 2C has a common configuration, and includes a microphone 20a, a speaker 20b, and a two-wire / four-wire conversion circuit, and performs signal processing on a sound signal output from the microphone 20a and a transmission line. Visiting with an audio signal processing unit 20 that processes audio signals transmitted through Ls1, Ls2, and Ls3 and generates sound from the speaker 20b, an individual image sensor such as a CCD or CMOS, and an optical system such as a lens And a video signal transmission unit that modulates the video signal output from the camera unit 21 with a frequency higher than that of the audio signal and transmits the frequency-modulated video signal via the transmission lines Ls1,. 22 and the audio signal output from the audio signal processing unit 20 and the video signal output from the video signal transmission unit 22 are frequency-multiplexed and transmitted. A demultiplexing unit 23 that transmits the signals to the lines Ls1, Ls2, and Ls3, and that separates audio signals transmitted from the master unit 1 and the sub-master units 4A to 4D via the transmission lines Ls1, Ls2, and Ls3, and the transmission lines Ls1, A call signal transmission unit 24 that transmits a call signal through Ls2 and Ls3, a control unit 25 that performs overall operation control with a microcomputer as a main component, and a control unit that receives an operation input of a call button (not shown) An operation input receiving unit 26 that outputs an operation signal to 25, and a power supply unit 27 that creates an operating power supply for each unit with power supplied from the base unit 1 via transmission lines Ls1, Ls2, and Ls3, as will be described later. It has.

  The power supply voltage (DC voltage) from the base unit 1 to the door phone sub-units 2A to 2C is intended to reduce the power consumption of the system when the door phone sub-unit 2A is not in a talking state or a monitor state (described later). Therefore, the state is relatively low, and the state is relatively high in the call state and the monitor state. Hereinafter, a state where the power supply voltage is low is referred to as a standby power supply state, and a state where the power supply voltage is high is referred to as an operation power supply state. In the intercom sub-units 2A to 2C, when in the standby power supply state, the microcomputer of the control unit 25 is in a standby state and waits for an operation signal to be output from the operation input receiving unit 26. When the operation signal is output from the input reception unit 26, the control unit 25 controls the call signal transmission unit 24 to reduce the line voltage of the transmission lines Ls1, ... to a voltage lower than that in the standby power supply state. A call signal is transmitted to the base unit 1. When the base unit 1 that has received the calling signal shifts the power supply voltage from the standby power supply state to the operation power supply state, the microcomputer of the control unit 25 returns from the standby state to the normal state, and the camera unit 21 and the video signal transmission unit 22 are switched on. When activated, the video signal is transmitted to the main unit 1 via the transmission lines Ls1,... And the audio signal processing unit 20 is activated to enable transmission / reception of the audio signal, that is, a state where a call can be made. Further, as will be described later, when the master unit 1 accepts an operation input for setting the door phone slave units 2A,. The camera unit 21 of the door phone 2A,... Is restored by returning from the normal state to starting the camera unit 21 and the video signal transmission unit 22 and transmitting the video signal to the base unit 1 via the transmission lines Ls1,. The video imaged at can be monitored by the master unit 1.

  The camera sub-units 3A to 3C all have a common configuration. The camera unit 30 includes an individual imaging element such as a CCD and a CMOS and an optical system such as a lens. Transmission line Ls1 between base unit 1 and video signal transmission unit 31 that modulates the output video signal at a frequency higher than that of the audio signal and transmits the frequency-modulated video signal via transmission lines Ls1,. ,..., And a human body detection that detects the presence of a person in the monitoring area and outputs a human body detection signal by detecting a heat ray radiated from the human body with a pyroelectric element. And a control unit 34 that controls the entire operation using a microcomputer as a main component. However, the operating power sources of the camera units 3A to 3C are created from a commercial power source by a power circuit (not shown).

  The control signal transmission unit 32 transmits the control signal by a frequency shift keying (FSK) method using a carrier wave having a frequency different from both the audio signal and the frequency-modulated video signal. In addition, a unique ID is assigned to each of the camera slave units 3A to 3C by a dip switch (not shown), and the base unit 1 and each of the camera slave units 3A are set by using this ID as a transmission destination or source address of the control signal. Control signals are individually transferred to and from 3C.

  In the camera sub-units 3A to 3C, the control unit 34 that has received the human body detection signal output from the human body detection unit 33 activates the camera unit 30 and the video signal transmission unit 31 to transmit the video signal obtained by imaging the monitoring region to the transmission line Ls1. The control unit 34 activates the camera unit 30 and the video signal transmission unit 31 to pick up an image of the monitoring area when it is transmitted to the main unit 1 via the control unit 34,. The video signal is transmitted to the main unit 1 via the transmission lines Ls1,.

  On the other hand, base unit 1 includes microphone 10a and speaker 10b, and a two-wire / four-wire conversion circuit, and processes audio signals output from microphone 10a and transmits the audio signals via transmission lines Ls1, Ls2, and Ls3. Receiving a video signal transmitted through the transmission line Ls1,..., An audio signal processing unit 10 that processes the signal and generates sound from the speaker 10b, a monitor unit 11 having a display device such as a liquid crystal display, and the like. A video signal processing unit 12 that demodulates and displays the image on the monitor unit 11 and displays various images based on screen data prepared in advance on the monitor unit 11, and monitors the line voltage of the transmission lines Ls1,. A call signal receiving unit 13 for receiving a call signal transmitted from the slave units 2A, ..., the camera slave units 3A to 3C, and the sub master unit 4A to A control signal transmission unit 14 that transmits a control signal to and from D by an FSK method, a demultiplexing unit 15 that frequency-multiplexes and separates an audio signal, a video signal, and a control signal, and a plurality of pushbutton switches (not shown) ) And a touch panel (not shown) disposed on the screen of the liquid crystal display of the monitor unit 11 to receive an operation input and output an operation signal corresponding to the received operation input; And a control unit 17 which controls the entire operation using a microcomputer as a main component. In addition, although not shown in figure, the power supply circuit which produces | generates the operation power supply of each part from commercial power supply, and supplies electric power to the door phone sub-units 2A-2C via transmission line Ls1, Ls2, Ls3 is also provided.

  As described above, for example, when the call signal transmitted from the door phone slave unit 2A is received by the call signal receiving unit 13, the control unit 17 of the base unit 1 operates the power supply voltage to the door phone slave unit 2A from the standby power supply state. The power supply state is shifted and the voice signal processing unit 10 is controlled to ring a ringing tone from the speaker 10b. On the other hand, in the intercom 2A, the microcomputer of the control unit 25 returns from the standby state to the normal state, activates the camera unit 21 and the video signal transmission unit 22, and transmits the video signal to the main unit 1 via the transmission lines Ls1,. The audio signal processing unit 20 is activated while transmitting. In the base unit 1, the video signal transmitted from the intercom unit 2 </ b> A is processed by the video signal processing unit 12 to display the visitor's video on the monitor unit 11. If a call button (not shown) formed of a pushbutton switch is pressed by looking at the video of the visitor displayed on the control unit 17, an operation signal is output from the operation input receiving unit 16 and the control unit 17 that has received the operation signal. Activates the audio signal processing unit 10 and sends and receives audio signals to and from the intercom unit 2A via the transmission line Ls1, so that a visitor and a dweller can talk.

  Further, when the presence of a person is detected in the monitoring area in any of the camera slave units (for example, the camera slave unit 3A), the control unit 34 that receives the human body detection signal output from the human body detection unit 33 performs the camera unit 30. In addition, the video signal transmission unit 31 is activated to transmit a video signal obtained by capturing an image of the monitoring area to the base unit 1 via the transmission line Ls1. In the base unit 1, the video signal transmitted from the camera slave unit 3 </ b> A is signal-processed by the video signal processing unit 12, and the video in the monitoring area is displayed on the monitor unit 11. Further, when a call signal transmitted from any one of the doorphone sub-units 2A,... Is received while displaying an image transmitted from the camera sub-unit 3A, or during a call with the doorphone sub-unit 2A,. When the video signal is transmitted from the camera slave unit 3A,..., The control unit 17 causes the video signal processing unit 12 to perform signal processing so that these two videos are displayed on the screen of the monitor unit 11 at the same time.

  Here, since the master unit 1 has only one video signal processing unit 12 that receives and processes video signals for the three transmission lines Ls1, Ls2, and Ls3, collision between the video signals is avoided. Therefore, the time division multiplex transmission system is adopted. That is, the doorphone sub-units 2A to 2C and the camera sub-units 3A to 3C are individually connected to a plurality of time slots defined by control signals transmitted from the control signal transmission unit 14 of the main unit 1 via the transmission lines Ls1, Ls2, and Ls3. Each slave unit transmits a video signal in the time slot assigned to itself, and the video signal processing unit 12 of the base unit 1 receives the received video signal in each time slot and reconstructs the original video from the demodulated video signal. It is configured and displayed on the monitor unit 11. However, the details of the time division multiplex transmission are well known in the art and will not be described.

  The secondary master units 4A to 4D all have a common configuration, and include a microphone 40a, a speaker 40b, and a two-wire / four-wire conversion circuit, and perform signal processing on the audio signal output from the microphone 40a and a transmission line. An audio signal processing unit 40 that processes an audio signal transmitted through Ls4 and generates sound from the speaker 40b, a monitor unit 41 having a display device such as a liquid crystal display, and the transmission line Ls4. The FSK is received between the base unit 1 and the video signal processing unit 42 that receives and demodulates the video signal, displays the video signal on the monitor unit 41, and displays various videos based on screen data prepared in advance on the monitor unit 41. The control signal transmission unit 43 that transmits the control signal according to the method, and the frequency signal multiplexing and separation of the audio signal, the video signal, and the control signal The demultiplexing unit 44, a plurality of push button switches (not shown), and a touch panel (not shown) disposed on the screen of the liquid crystal display included in the monitor unit 41 are provided to accept and accept operation inputs. Are provided with an operation input receiving unit 45 that outputs an operation signal corresponding to the control unit 46, and a control unit 46 that performs overall operation control using a microcomputer as a main component. Each secondary master unit 4A to 4D is assigned a unique ID (an ID different from the IDs of the camera slave units 3A to 3C) by a dip switch (not shown), and this ID is assigned to the transmission destination or transmission source of the control signal. By using this address, control signals are individually exchanged between the master unit 1 and the sub-master units 4A to 4D.

  Here, when the master unit 1 receives a call signal from the door phone slave unit 2A,..., It calls the sub master units 4A to 4D from the door phone slave unit 2A,... (Hereinafter referred to as “door phone call”). A control signal for notifying the user is transmitted, and, as will be described later, an operation for performing a one-to-one or one-to-many extension call between the master unit 1 and the sub-master units 4A to 4D has been performed. Sometimes, a control signal for notifying a call to the secondary master units 4A to 4D (hereinafter referred to as "extension call") is transmitted. In the sub master unit 4A,..., When the control signal transmission unit 43 receives the doorphone call control signal transmitted from the base unit 1, the control unit 46 controls the voice signal processing unit 40 to ring the ring tone from the speaker 40b. In addition, the video signal transmitted from the intercom unit 2A,... Via the master unit 1 is processed by the video signal processing unit 42, and the video of the visitor is displayed on the monitor unit 41. If a resident sees the video of the visitor displayed on the monitor unit 41 and presses a call button (not shown) including a push button switch, an operation signal is output from the operation input receiving unit 45, and the operation The control unit 46 that has received the signal activates the audio signal processing unit 40 and exchanges audio signals with the intercom 2A,... Via the transmission lines Ls1 to Ls3 and Ls4. Can call. Alternatively, when the control signal transmission unit 43 receives the extension call control signal transmitted from the base unit 1, the control unit 46 of the secondary base unit 4A,... Controls the voice signal processing unit 40 to generate a ringing tone from the speaker 40b. If the dweller who hears the ringing tone presses a call button (not shown) including a pushbutton switch, an operation signal is output from the operation input receiving unit 45, and the control unit 46 that receives the operation signal By starting the audio signal processing unit 40 and exchanging audio signals with the sub-master units 4A,... Via the transmission lines Ls1 to Ls3, Ls4, the residents can make a call (extension call).

  Here, in the master unit 1 and the sub master units 4A to 4D, any one of the door phone slave units 2A to 2C or the camera slave units 3A to 3C is selected, and a video signal is transmitted to the selected slave unit to monitor unit 11 , 41 has a function of displaying video (video monitor function). For example, when performing video monitoring of the door phone slave unit 2C, the control unit 17 of the base unit 1 shifts the power supply voltage to the door phone slave unit 2C from the standby power supply state to the operation power supply state. As a result, the microcomputer of the control unit 25 of the door phone slave unit 2C returns from the standby state to the normal state, activates the camera unit 21 and the video signal transmission unit 22, and transmits the video signal to the base unit 1 via the transmission line Ls3. As a result, the video captured by the camera unit 21 of the door phone slave unit 2C can be displayed on the monitor unit 11 of the base unit 1 to perform video monitoring. Alternatively, when the video monitoring of the camera slave unit 3C is performed, the control unit 17 of the parent device 1 transmits a control signal including a command requesting the camera slave unit 3C to transmit a video signal from the control signal transmission unit 14. Let Then, in the camera slave unit 3C that has received this control signal by the control signal transmission unit 32, the control unit 34 activates the camera unit 30 and the video signal transmission unit 31, and sends the video signal to the master unit 1 via the transmission line Ls3. Send. As a result, the base unit 1 can perform video monitoring by displaying the video captured by the camera unit 30 of the camera slave unit 3C on the monitor unit 11. When video monitoring is performed by the secondary master units 4A to 4D, a control signal including a video monitor start request specifying the target doorphone slave units 2A to 2C or the camera slave units 3A to 3C is sent from the secondary master units 4A to 4D. By transmitting to the master unit 1, the master unit 1 transmits the video signal to the designated slave unit, and video is transmitted from the doorphone slave units 2A to 2C or the camera slave units 3A to 3C via the master unit 1. A signal can be received and an image can be displayed on the monitor unit 41 of the sub-master units 4A to 4D.

  By the way, in the base unit 1, when a monitor button (push button switch) (not shown) is pressed and an operation signal is output from the operation input receiving unit 16, the control unit 17 that receives the operation signal causes the video signal processing unit 12 to operate. As shown in FIG. 2 (a), an image (hereinafter referred to as the following) in which buttons B1 to B6 corresponding to slave units (door phone slave units 2A to 2C and camera slave units 3A to 3C) that can be monitored are arranged vertically and horizontally. This is called a “video monitor selection screen.”) G1 is displayed on the monitor unit 11. For example, when the display position of the button B4 corresponding to the camera slave unit 3A is touched on the video monitor selection screen, an operation signal indicating the touch position of the touch panel is output from the operation input receiving unit 16 to the control unit 17, Based on the operation signal, the control unit 17 recognizes that the button B4 has been operated. Then, the control unit 17 determines that the camera slave unit 3A corresponding to the button B4 has been selected, and transmits the video signal to the camera slave unit 3A and displays the video on the monitor unit 11 as described above. Further, in base unit 1, when an unillustrated extension call button (push button switch) is pressed and an operation signal is output from operation input receiving unit 16, control unit 17 that has received the operation signal receives video signal processing unit 12. As shown in FIG. 2 (c), a monitor G is an image (hereinafter referred to as "extension call selection screen") G2 in which buttons B10 to B14 corresponding to the sub-master units 4A to 4D are arranged vertically and horizontally. 11 (however, the button B10 is a button corresponding to a simultaneous call for calling all the sub-master devices 4A to 4D all at once). For example, when the display position of the button B11 corresponding to the sub master unit 4A is touched on the extension call selection screen G2, an operation signal indicating the touch position of the touch panel is output from the operation input receiving unit 16 to the control unit 17, Based on this operation signal, the control unit 17 recognizes that the button B11 has been operated. Then, the control unit 17 determines that the secondary master unit 4A corresponding to the button B11 has been selected, and transmits an extension call control signal to the secondary master unit 4A as described above. That is, in the present embodiment, the buttons B4 to B6 and B11 to B14 corresponding to the camera slave units 3A to 3C and the sub master units 4A to 4D on a one-to-one basis correspond to the identification information.

  Here, if any of the camera slave units 3A to 3C and the secondary master units 4A to 4D are intentionally stopped (power is turned off) or removed from the transmission lines Ls1,. However, the buttons B4 to B6 corresponding to the camera slave units 3A to 3C that cannot actually transmit data (video signals) are displayed on the video monitor selection screen G1, or the data (control signal for extension call) is displayed. When the buttons B11 to B14 corresponding to the secondary master units 4A to 4D that cannot transmit are displayed on the extension call selection screen G2, as described in the prior art, the camera slave units 3A to 3C and the secondary master unit 4A that cannot transmit data are provided. There is a possibility that ~ 4D may be selected by mistake.

  Therefore, in the present embodiment, a control signal including data for checking operation (check data) is periodically transmitted from the master unit 1 to the camera slave units 3A to 3C and the sub master units 4A to 4D. When a control signal including a response to the check data (acknowledgment: ACK) is not transmitted from the camera slave units 3A to 3C or the sub master units 4A to 4D within a certain time, a camera slave unit that has not responded (for example, The button B5 corresponding to the camera slave unit 3B) is not displayed on the video monitor selection screen G1 (see FIG. 2 (b)), or it corresponds to the secondary master unit that has not responded (for example, secondary master unit 4D). The button B14 is not displayed on the extension call selection screen G2.

  That is, the control unit 17 of the master unit 1 performs control including transmission and response of a control signal including check data while sequentially polling the IDs of the camera slave units 3A to 3C and the sub master units 4A to 4D at regular time intervals. The presence (operating state) of the camera slave units 3A to 3C and the secondary master units 4A to 4D is periodically confirmed by repeatedly receiving signals, and each camera slave unit 3A to 3C and secondary master unit are stored in a memory (not shown). The presence confirmation results (presence / absence) of 4A to 4D are stored in association with IDs. When the monitor button or the extension call button is operated, the control unit 17 of the base unit 1 is assigned the ID if the presence confirmation result stored in the memory is absent. The buttons B4 to B6 and B11 to B14 corresponding to the camera slave units 3A to 3C and the sub master units 4A to 4D are deleted from the video monitor selection screen G1 or the extension call selection screen G2 and are not displayed.

  Therefore, the camera slave units 3A to 3C and the secondary master units 4A to 4D that do not return a response to the check data are regarded as being unable to transmit data, and the buttons B4 to B6 and B11 to B14 as identification information are selected as video monitors. By deleting from the screen G1 or the extension call selection screen G2 and not displaying it on the monitor unit 11 of the master unit 1, the camera slave units 3A to 3C and the sub master units 4A to 4D that cannot transmit data are displayed on the video monitor selection screen G1 or Incorrect selection on the extension call selection screen G2 can be prevented. In addition, since the transmission of the control signal including the check data is performed by the polling method, it is possible to prevent the control signal including the check data and the control signal including the response to the check data from colliding with each other. There is an advantage that time can be shortened. Since the doorphone sub-units 2A to 2C are supplied with power from the base unit 1 via the transmission lines Ls1, Ls2, and Ls3, the current flowing through the transmission lines Ls1, Ls2, and Ls3 (= doorphone sub-units 2A to 2C). It is possible to confirm the presence (operating state) by measuring the current consumption. However, the presence (operating state) of the doorphone sub-units 2A to 2C may be confirmed using the control signal in the same manner as the camera sub-units 3A to 3C.

  By the way, since the video monitor selection screen G1 and the extension call selection screen G2 are also displayed on the monitor unit 41 of the secondary master units 4A to 4D, the control unit 46 of the secondary master unit 4A to 4D also uses the camera slave units 3A to 3A. It is necessary to know the presence (operating state) of 3C and the other secondary master units 4A to 4D. For this purpose, the control unit 17 of the base unit 1 transmits a control signal including the existence confirmation result read from the memory before each control signal including check data is periodically transmitted to the secondary base units 4A to 4D. I have to. As a result, the control unit 46 of each sub master unit 4A to 4D can grasp the presence (operation state) of the camera slave units 3A to 3C and the other sub master units 4A to 4D, and the presence confirmation result is absent. If there is an ID, the buttons B4 to B6 and B11 to B14 corresponding to the camera slave units 3A to 3C and the sub master units 4A to 4D to which the ID is assigned are displayed on the video monitor selection screen G1 or the extension call selection screen. It can be deleted from G2 and not displayed.

It is a system configuration figure showing an embodiment (intercom system) of the present invention. (A)-(d) is operation | movement explanatory drawing same as the above.

Explanation of symbols

1 Intercom master unit (master station)
3A-3C Camera slave unit (Camera slave station)
4A-4D Interphone sub-master (calling slave station)
11 Monitor section (display means)
12 Video signal processor (display control means)
14 Control signal transmission unit (transmission control means)
16 Operation input reception part (operation input reception means)
17 Control unit (transmission control means, display control means)

Claims (3)

A transmission system in which a plurality of slave stations are connected to a master station via a transmission line, and data is transmitted between the master station and each slave station via the transmission line,
The master station displays at least one identification information corresponding to each slave station, and receives an operation input for receiving an operation input for selecting any of the slave stations based on the identification information displayed on the display means. Means, transmission control means for transmitting data to the selected slave station, and data for operation confirmation periodically transmitted to all slave stations from the transmission control means, and for the operation confirmation data And a display control means for preventing the identification information of the slave station from which no response is returned from being displayed on the display means.   The transmission system according to claim 1, wherein the transmission control means transmits the operation check data by a polling method. The slave station includes a camera slave station that transmits video data imaged by the imaging means, and a call slave station that transmits voice data for a call between the master station,
The master station is configured to display video data transmitted from the selected camera slave station on the display means, and to sound the voice based on the audio data received from the selected call slave station and to hear the voice of the speaker The transmission system according to claim 1 or 2, further comprising: call means for converting the voice data into voice data and transmitting the voice data to the call slave station from the transmission control means.

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