JP5049243B2 - Intercom system - Google Patents

Description

  The present invention relates to an intercom system.

  In a conventional interphone system, interphone master units, interphone sub-master units, and interphone slave units are connected by call wiring, for example, one interphone master unit and one interphone sub-master unit communicate with each other. Since the transmission line is occupied by the two telephone devices during the period, a plurality of sets of telephone devices could not talk at the same time.

  On the other hand, voice and video are converted into digital data, and the digital data (voice data and video data) is divided into packets and transmitted, so that the transmission line is time-sharing and multiple sets of telephone devices can talk simultaneously. A possible intercom system has been proposed (see, for example, Patent Document 1). In the conventional system described in Patent Document 1, a plurality of communication devices are branched and connected to a common transmission line via branching units, and each communication device is carrier detection multiple access collision detection (CSMA / CD). The packet is multiplexed and transmitted. This CSMA / CD method is a communication method in which any call device can transmit if a no-signal state continues on a transmission line for a certain time (gap between frames), and the call device detects no signal. A carrier signal detection function for detecting a signal collision and a collision detection function for detecting a signal collision. When a signal collision is detected, the calling device temporarily stops transmission and tries to transmit the signal again after a predetermined time.

  Here, in an interphone system in which a large number of communication devices (slave devices and master devices <including sub-master devices>) are branched and connected to a common transmission line via a branching device, they are transmitted from one communication device. Since the transmission signal passes through the two branching devices until it is received by another communication device, carrier sense cannot be performed due to the large attenuation of the transmission signal when passing through the branching device. There is a possibility that collision of transmission signals (packets) frequently occurs.

On the other hand, in an intercom system in which the main device and a plurality of terminals are connected to a common transmission line, the main device always polls the plurality of terminals, and only one terminal to which a transmission right is given from the main device. A polling system that transmits a transmission signal has been proposed (see, for example, Patent Document 2). In the conventional example described in Patent Document 2, since the collision of transmission signals is prevented by adopting the polling method, each terminal does not need to perform carrier detection.
JP 2005-136663 A Japanese Patent No. 3686517

  As described above, since the polling method is employed in the conventional example described in Patent Document 2, each terminal (calling device) does not perform carrier detection, so there are a plurality of branching devices between the terminals. But there is no hindrance to collision avoidance. However, in the conventional example described in Patent Document 2, since the main apparatus polls a plurality of terminals in order and gives a transmission right, the opportunity for each terminal to actually transmit a transmission signal is the polling cycle. It will be limited. For this reason, the right to transmit is given to a terminal that is not making a call, and the waiting time (transmission in each terminal increases as the number of terminals (slave units and base units) branched and connected to a common transmission line increases. Since the period in which the right is given increases, the data transmission efficiency may be reduced.

  The present invention has been made in view of the above circumstances, and its purpose is to reduce transmission efficiency even in a system configuration in which a plurality of slave units and a master unit are branched and connected to a common transmission line via a branching unit. It is another object of the present invention to provide an intercom system capable of avoiding a collision and multiplexing and transmitting audio.

  In order to achieve the above object, the first aspect of the present invention provides a plurality of slave units branch-connected to the first transmission line via branching units, and branches to the second transmission line via branching units. It has a plurality of connected master units and a relay device connected to the first and second transmission lines without going through branching units, and the slave unit and the master unit collect voices uttered by a speaker. Collecting means, data converting means for converting the sound collected by the sound collecting means into digital data, and a packet containing the sound data converted by the data converting means via the first or second transmission line Transmitting means for transmitting; receiving means for receiving a packet transmitted through the first or second transmission line; and digital / analog for converting audio data contained in the packet received by the receiving means into an analog audio signal Conversion means and digital / analog A first communication unit that transmits a packet to and from the slave unit via the first transmission line. And a second communication means for transmitting packets to and from the base unit via the second transmission line, and a packet received by the first communication means is transmitted from the second communication means. A relay processing unit that transmits a packet received by the second communication unit from the first communication unit, and the relay processing unit, when an event for starting a call between any of the slave units and the master unit occurs, A packet including a transmission start command for giving a transmission right to the child device and the parent device is transmitted from the first and second communication means, and the child device and the parent device are transmitted before transmission of the packet including the transmission start command. Relay to each One or a plurality of packets to be transmitted are transmitted from the first and second communication means, and when the slave unit receives a packet including a transmission start command transmitted from the relay device by the reception unit, the slave unit converts the packet by the data conversion unit. Control means for transmitting one or more packets including voice data from the transmission means and for transmitting a packet including a transmission end command for returning the transmission right to the relay apparatus after transmission of the packets from the transmission means. When the reception unit receives a packet including a transmission start command transmitted from the relay device, the base unit causes the transmission unit to transmit one or more packets including voice data converted by the data conversion unit, and transmits the packet. Control means for sending a packet including a transmission end command for returning the transmission right to the relay apparatus later from the transmission means. The relay processing unit of the relay device receives the packet including the transmission end command transmitted from the slave unit and the base unit by the first and second communication units and then receives the packet including the next transmission start command as the first and second packets. It is characterized by transmitting from the second communication means.

  According to the first aspect of the present invention, since the relay processing unit of the relay apparatus does not transmit the packet including the transmission start command from the first and second communication units until an event for starting a call occurs, The data transmission efficiency does not decrease compared to the case of constant polling as in the example. In addition, when the event occurs, the relay processing unit of the relay device transmits a packet including a transmission start command from the first and second communication units, and sequentially gives a transmission right to each of the plurality of slave units and the plurality of master units. Therefore, a plurality of sets of the child device and the parent device can talk simultaneously while avoiding collision of packets transmitted from the plurality of child devices and the plurality of parent devices. As a result, even in a system configuration in which a plurality of slave units and a master unit are branched and connected to a common transmission line via a branching unit, it is possible to avoid a collision and multiplex transmit audio without reducing transmission efficiency. Become.

  According to a second aspect of the present invention, in the first aspect of the invention, the relay processing means of the relay device causes the packet including voice data to be transmitted from the first and second communication means including the transmission start command. The control unit of the master unit includes the transmission end command included in the packet including the audio data and causes the transmission unit to transmit the packet.

  According to the invention of claim 2, the transmission efficiency can be improved as compared with the case where the transmission start command and the transmission end command are transmitted in a dedicated packet.

  According to a third aspect of the present invention, in the first or second aspect of the invention, when the relay processing means of the relay apparatus transmits a plurality of packets from the first and second communication means, the transmission destination slave and master The control unit of the slave unit and the base unit transmits the plurality of packets from the transmission unit according to the transmission line length up to the relay device. The plurality of packets are transmitted with a certain time interval.

  According to the third aspect of the present invention, it is not necessary to provide a time interval corresponding to the round trip of the transmission line length as in the normal CSMA method, so that time efficiency can be improved.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the slave unit includes an imaging unit that captures an image of a speaker, a video data conversion unit that converts video captured by the imaging unit into digital data, and a video data conversion unit. The transmission means for transmitting the packet containing the video data converted in step 1 through the first transmission line, and the master unit includes the display means for displaying the video and the video data included in the packet received by the reception means. And a video signal processing means for displaying the video on the display means, and the relay processing means of the relay device transmits the packet including the video data from the second communication means including the transmission start command, The control unit of the slave unit includes the transmission end command included in the packet including the video data and causes the transmission unit to transmit the packet.

  According to the invention of claim 4, the transmission efficiency can be improved as compared with the case where the transmission start command and the transmission end command are transmitted in a dedicated packet.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the transmission start command and the transmission end command include a flag included in a packet header.

  According to the invention of claim 5, it is possible to shorten the transmission time of the packet including the transmission start command and the transmission end command.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the relay processing means of the relay device continues a plurality of packets including data of the same content from the first and second communication means. The slave unit and the control unit of the master unit continuously transmit a plurality of packets including the same content data from the transmission unit, and the transmission start command or the transmission end command is transmitted to the same content data. May be included.

  According to the sixth aspect of the present invention, data having the same contents can be transmitted reliably.

  According to the present invention, even in a system configuration in which a plurality of slave units and a master unit are branched and connected to a common transmission line via a branching unit, it is possible to multiplex and transmit audio while avoiding a collision without reducing transmission efficiency. Is possible.

  As shown in FIG. 1, the intercom system according to the present embodiment includes a plurality of (two in the illustrated example) children that are branched and connected to a first transmission line Ls1 made of a pair wire, a coaxial cable, or the like via branching devices B. A plurality of (two in the illustrated example) master units M1 and M2 that are branched and connected to the second transmission line Ls2 that is also composed of a pair line, a coaxial cable, and the like via a branching device B, respectively, And a relay device R connected to the first and second transmission lines Ls1 and Ls2 without using the branching device B, respectively. In addition, the transmission line which connects each branch device B and the subunit | mobile_unit S1, S2 or the main | base station M1, M2 is called a branch line. Also, the number of slave units or master units may be three or more.

  The subunits S1 and S2 convert and compress the microphone 20 that collects the voice produced by the speaker (visitor) and the voice (analog voice signal) collected by the microphone 20 into digital data (voice data). Voice encoder 21, voice decoder 22 that decompresses voice data and converts it into an analog voice signal, speaker 23 that is driven by the voice signal and rings voice, and camera 24 that captures the image of the speaker (visitor) A video encoder 25 that converts the video (analog video signal) captured by the camera 24 into digital data (video data) and compresses it, and a packet that includes audio data and video data with the CPU as the main components. Or a child device control unit 26 that performs signal processing such as obtaining voice data from packets received from the parent devices M1 and M2, and a child device A transmission unit 27 that digitally modulates a carrier wave (for example, phase shift keying <PSK>) by the packet generated by the control unit 26 and transmits the carrier via the first transmission line Ls1, and a first transmission line A receiver 28 that receives a packet via Ls1 and digitally demodulates the packet and outputs it to the handset controller 26, and a call button (not shown), and a call button of a speaker (visitor) An operation receiving unit 29 that receives an operation and outputs an operation signal to the child device control unit 26 is provided. The camera 24 is a well-known camera, and includes a CCD image sensor, a CMOS image sensor, an optical system such as a lens, and the like to capture a moving image (video).

  Master devices M1 and M2 convert and compress the microphone 1 that collects the sound produced by a speaker (resident) and the sound (analog voice signal) collected by the microphone 1 into digital data (voice data). An audio encoder 2; an audio decoder 3 that expands audio data and converts it into an analog audio signal; a speaker 4 that is driven by the audio signal to ring audio; a video decoder 5 that expands video data; and a video decoder The display unit 6 that displays the video expanded in 5 and the CPU as a main component generate a packet including audio data, or acquire audio data and video data from the packets received from the slave units S1 and S2. The base unit control unit 7 that executes signal processing such as the above, and the carrier wave (carrier) is digitally modulated by the packet generated by the base unit control unit 7 (for example, , Phase shift keying <PSK>, etc.) for transmission via the second transmission line Ls2, and receiving the packet via the second transmission line Ls2, and digitally demodulating the packet to obtain the master unit It has a receiving unit 9 that outputs to the control unit 7 and a response button (not shown) for responding to a call from the slave units S1 and S2, and accepts an operation of the response button by a speaker (resident) to receive the master unit An operation receiving unit 10 that outputs an operation signal to the control unit 7 is provided. Note that the display unit 6 is a conventionally known display unit including a display device such as a liquid crystal display and a drive circuit for driving the display device.

  The branching device B includes a branching transformer 30, a series circuit of a capacitor 31 and a resistor 32 inserted between one winding (primary winding) of the branching transformer 30 and the transmission line Ls 1 or Ls 2, and the branching transformer 30. The capacitor 33 is inserted between the other winding (secondary winding) and the branch line. The branch transformer 30 has a primary side (primary winding side) impedance set to a value sufficiently higher than the characteristic impedance of the first and second transmission lines Ls1, Ls2, and the secondary side (secondary winding). Side) impedance is set equal to the characteristic impedance of the branch line.

  The relay device R includes a first receiver 40 that receives packets transmitted from the slave units S1 and S2 via the first transmission line Ls1, and a slave unit S1 and slave units via the first transmission line Ls1. A first transmission unit 41 that transmits packets to S2, a second reception unit that receives packets transmitted from the parent devices M1 and M2 via the second transmission line Ls2, and a second transmission line Ls2. A second transmission unit 43 that transmits packets to the parent devices M1 and M2 through the first transmission unit 43, and a second reception unit 43 that transmits a packet received by the first reception unit 40 with the CPU as a main component. The signal processing unit 44 that executes a relay process for transmitting the packet received by the first reception unit 42 from the first transmission unit 41 and the packets received by the first and second reception units 40 and 42 are temporarily stored. Storage unit (buffer memory) 45 It is equipped with a.

  Further, the signal processing unit 44 of the relay device R calls an event for starting a call between any of the slave units S1 and S2 and the master units M1 and M2 (calling from the slave unit S1 or S2 to the master unit M1 or M2 as described later) When a signal is transmitted), a packet including a transmission start command for giving a transmission right to the slave unit S1 or S2 and the master unit M1 or M2 is sent to the first and second transmission units 41, The first and second transmission units 41 and 43 transmit one or more packets to be transmitted from the terminal 43 and relayed to the child device S1 or S2 and the parent device M1 or M2 before transmission of the packet including the transmission start command. To send from.

  On the other hand, the slave unit control unit 26 of the slave units S1 and S2 transmits a call signal from the transmission unit 27 when receiving the call signal from the operation accepting unit 29. This call signal uses the address (identification code) assigned to the call destination master unit M1 or M2 as the destination address, and the address (identification code) assigned to the slave unit S1 or S2 on which the call button is operated. Is a transmission source address and a call command is data. The transmission unit 27 digitally modulates and transmits the packet. In addition, as a method of specifying the called master device M1 or M2, a correspondence relationship between the slave devices S1 and S2 and the master devices M1 and M2 (for example, the slave device S1 and the master device M1, and the slave device S2 and the master device M2). And the like, or a method in which two call buttons corresponding to the respective parent devices M1 and M2 are provided in the operation reception unit 29.

  In the slave unit control unit 26, when the reception unit 28 receives a packet including a transmission start command transmitted from the relay device R, the slave unit control unit 26 includes a packet including video data converted by the video encoder 25 (hereinafter referred to as a "video packet"). ) And packets including the audio data converted by the audio encoder 21 (hereinafter referred to as “audio packets”) are transmitted from the transmission unit 27, and after these packets are transmitted, the transmission right to the relay device R is transmitted. The transmission unit 27 transmits a packet including a transmission end command for returning.

  Here, the packet is composed of a header part including a preamble and an address (destination address and transmission source address), a data part composed of audio data and video data, and a footer part including an error correction code. Is provided with a start flag and an end flag. That is, a packet having a start flag bit of “1” and an end flag bit of “0” is a packet including a transmission start command, a start flag bit of “0” and an end flag bit of “1”. The packet becomes a packet including a transmission end command.

  On the other hand, when the destination address of the call signal (packet including the call command in the data portion) matches the address assigned to itself, the parent device control unit 7 of the parent devices M1 and M2 stores it in a memory (not shown). The data of the existing ringing tone is expanded by the voice decoder 3 and the ringing tone is emitted from the speaker 4. When the operation accepting unit 10 accepts the operation of the response button and outputs an operation signal, the base unit control unit 7 that has received the operation signal causes the transmission unit 8 to transmit a response signal. This response signal is composed of a packet having the address (identification code) assigned to the relay device R as the destination address, the address of the parent device M1 or M2 as the source address, and the response command as data. 8 is digitally modulated and transmitted. Further, when the base unit control unit 7 receives the packet including the transmission start command transmitted from the relay device R by the reception unit 9, the base unit control unit 7 transmits the packet (voice packet) including the voice data converted by the voice encoder 2 from the transmission unit 8. The transmitter 8 transmits a packet including a transmission end command for returning the transmission right to the relay apparatus R after transmitting the voice packet.

  Next, the operation of the present embodiment will be described in more detail with reference to the time charts of FIGS. However, in the following description, it is assumed that a call is performed in the combination of the slave unit S1 and the master unit M1, and in the combination of the slave unit S2 and the master unit M2.

  2 and 3 correspond to the parent devices M1 and M2, the second horizontal line from the top corresponds to the second transmission line Ls2 side in the relay device R, and the third horizontal line from the top. Corresponds to the first transmission line Ls1 side in the relay device R, and the bottom horizontal line corresponds to the slave units S1 and S2. Each horizontal line represents a time axis.

  First, referring to FIG. 2, a description will be given of a case where a call is made only with a combination of the slave unit S1 and the master unit M1.

  First, when a call button of the child device S1 is operated by a speaker (visitor) and an operation signal is output from the operation accepting unit 29 to the child device control unit 26, the child device control unit 26 receives the address of the parent device M1. Is generated as a destination address and a packet (call signal) CP including a call command in the data portion is transmitted from the transmission unit 27. At this time, the transmission unit 27 performs carrier sense on the branch line, and when a carrier is detected, transmits a call signal CP after a predetermined waiting time has elapsed. Here, as described in the prior art, a packet transmitted from another child device S2 and reaching the child device S1 is greatly attenuated because it passes through the two branch devices B, and the carrier sense of the packet is It can't be done in practice. Therefore, the carrier sense performed by the transmission unit 27 of the child device S1 is the carrier sense for the packet transmitted from the relay device R. In addition, the child device control unit 26 of the child device S1 activates the camera 24 to take an image of a speaker (visitor) and outputs video packets VP1 and VP2 including video data output from the camera 24 and compressed by the video encoder 25. , VP3 are generated and temporarily stored in a memory (not shown). Here, since the amount of video data is much larger than that of audio data, one frame of video data is divided into a plurality of (three in the illustrated example), and the divided video data is divided into video packets VP1, VP2, and VP2, respectively. It is stored in the data part of VP3. However, the division number of the video data is not limited to three, and may be two or four or more.

  The call signal CP transmitted from the child device S1 is relayed by the relay device R and received by the parent device M1. At this time, the signal processing unit 44 of the relay device R transmits the packet SP including the transmission start command to the child device S1 after relaying the calling signal CP to the parent device M1. Note that the packet SP is a packet that has a start flag bit of “1” and an end flag bit of “0” in the header portion and does not have a data portion. Thus, the transmission efficiency can be improved because the packet SP does not have a data portion.

  Since the slave unit control unit 26 of the slave unit S1 is given the transmission right from the relay device R by receiving the packet SP, the transmission unit 27 receives the video packets VP1, VP2, and VP3 stored in the memory. To send from. The video packets VP1, VP2, and VP3 transmitted from the child device S1 are relayed by the relay device R and received by the parent device M1.

  When base unit control unit 7 of base unit M1 receives call signal CP transmitted from slave unit S1 and relayed by relay device R by reception unit 9, ring unit data stored in a memory (not shown) is voiced. The decoder 3 decompresses the ringing sound from the speaker 4. Further, in base unit M1, when receiving unit 9 receives video packets VP1, VP2, and VP3 transmitted from slave unit S1 and relayed by relay device R, base unit control unit 7 receives video packets VP1, VP2, and VP3. The acquired video data is combined to restore the original video data (one frame worth of video data), and the restored video data is output to the video decoder 5. Then, the video data is decompressed by the video decoder 5 and the video (visitor video) is displayed on the display unit 6. The speaker (resident) on the base unit M1 side confirms the other speaker (visitor) on the video displayed on the display unit 6, and operates the response button when answering the call.

  When a response button of the base unit M1 is operated by a speaker (resident) and an operation signal is output from the operation receiving unit 10 to the base unit control unit 7, the base unit control unit 7 sets the address of the relay device R as a destination address. And a packet (response signal) RP including a response command in the data part is generated and transmitted from the transmission unit 8. At this time, the transmission unit 8 performs carrier sense on the branch line, and when a carrier is detected, transmits a response signal RP after a predetermined waiting time has elapsed. The carrier sense performed by the transmission unit 8 of the base unit M1 is carrier sense for a packet transmitted from the relay device R. The base unit control unit 7 of the base unit M1 generates a voice packet AP 'including voice data collected by the microphone 1 and compressed by the voice encoder 2, and temporarily stores it in a memory (not shown).

  When the response signal RP transmitted from the parent device M1 is received by the second receiving unit 42 of the relay device R, the signal processing unit 44 of the relay device R transmits the packet SP including the transmission start command to the parent device M1. To do. Note that the packet SP is a packet that has a start flag bit of “1” and an end flag bit of “0” in the header portion and does not have a data portion.

  Since the base unit control unit 7 of the base unit M1 receives the packet SP, the transmission right is given from the relay device R. Therefore, the transmission unit 8 transmits the voice packet AP ′ stored in the memory. . At this time, the base unit control unit 7 transmits a transmission end command by the voice packet AP 'by setting the bit of the start flag in the header part to "0" and the bit of the end flag to "1".

  When the voice packet AP ′ transmitted from the parent device M1 is received by the second receiving unit 42, the signal processing unit 44 of the relay device R transmits from the parent device M1 by a transmission end command included in the voice packet AP ′. Detect that the right has been returned. Further, the signal processing unit 44 changes the bit of the start flag in the header portion of the voice packet AP ′ to “1” and the bit of the end flag to “0”, and causes the first transmission unit 41 to transmit. That is, the signal processing unit 44 transmits a transmission start command to the child device S1 by the voice packet AP 'relayed to the child device S1.

  In the handset S1, the handset control unit 26 acquires the sound data from the sound packet AP ′ received by the receiving unit 28, and the sound data is decompressed by the sound decoder 22, so that the speaker ( The sound uttered by the resident) is caused to ring from the speaker 23. In the slave unit S1, an audio packet AP including audio data collected by the microphone 1 and compressed by the audio encoder 2, and a video packet VP1 including video data output from the camera 24 and compressed by the video encoder 25 are displayed. , VP2, VP3 are generated and temporarily stored in the memory. Since the transmission right is given from the relay device R by receiving the audio packet AP ′, the slave unit control unit 26 uses the video packets VP1, VP2, VP3 and the audio packet AP stored in the memory. Is transmitted from the transmitter 27. At this time, the slave unit control unit 26 sets the bit of the start flag in the header part of the packet (voice packet AP) to be transmitted last to “0” and the bit of the end flag to “1”. Send a send end command. However, when the audio packet AP is transmitted first, the transmission end command may be transmitted with the last video packet VP3 among the video packets VP1, VP2, and VP3 transmitted later.

  When the video packet VP1, VP2, VP3 and the audio packet AP transmitted from the child device S1 are received by the first receiving unit 40, the signal processing unit 44 of the relay device R transmits a transmission end command included in the audio packet AP. By this, it is detected that the transmission right is returned from the slave unit S1. Further, the signal processing unit 44 changes the bit of the start flag in the header part of the voice packet AP to “1” and the bit of the end flag to “0” and causes the second transmission unit 43 to transmit it. A transmission start command is transmitted to the machine M1.

  In base unit M1, when receiving unit 9 receives video packets VP1, VP2, and VP3 and audio packet AP transmitted from slave unit S1 and relayed by relay device R, base unit control unit 7 receives the video packets VP1 and VP2. , The video data obtained from VP3 is combined to restore the original video data (one frame worth of video data), the restored video data is output to the video decoder 5 and displayed on the display unit 6 (video of the visitor). And the voice data acquired from the voice packet AP is expanded by the voice decoder 22, so that the voice uttered by the speaker (visitor) on the handset S 1 side is caused to ring from the speaker 4.

  When the transmission right is given from the relay device R by receiving the voice packet AP, the base unit control unit 7 of the base unit M1 causes the transmission unit 8 to transmit the voice packet AP 'stored in the memory. At this time, the base unit control unit 7 transmits the transmission end command by the voice packet AP ′ by setting the bit of the start flag in the header part to “0” and the bit of the end flag to “1”.

  Thereafter, the transmission right is periodically given from the relay device R to the slave unit S1 and the master unit M1, and the video packet VP1, VP2, VP3 and the voice packet are transmitted from the slave unit S1 only while the transmission right is given. AP is transmitted, and voice packet AP ′ is transmitted from base unit M1.

  Next, with reference to FIG. 3, a case will be described in which a call is made with a combination of the child device S2 and the parent device M2 in a situation where a call is made with the combination of the child device S1 and the parent device M1.

  First, the operations of the slave unit S2, the master unit M2, and the relay device R until the call is started after the call signal CP is transmitted from the slave unit S2 and the response signal RP is transmitted from the callee master unit M2 are described above. It is as follows. However, the transmission of the call signal CP and the response signal RP from the slave unit S2 and the master unit M2 is carrier-sensed by the transmitter 27 of the slave unit S2 and the transmitter 8 of the master unit M2, and the packet is transmitted from the relay device R. Not done at the timing.

  In the relay device R, the video packet VP1 (1), VP2 (1), VP3 (1) and the voice packet AP (1) transmitted from the child device S1 and received by the first receiving unit 40 are temporarily stored in the storage unit 45. The voice packet AP ′ (2) transmitted from the parent device M2 and received by the second reception unit 42 is transmitted from the first transmission unit 41 and relayed to the child device S2, and then stored in the storage unit. The video packets VP1 (1), VP2 (1), VP3 (1) and the audio packet AP (1) read from 45 are transmitted from the second transmission unit 43 and relayed to the base unit M1. At this time, the signal processing unit 44 transmits the transmission start command by the voice packets AP (1) and AP ′ (2) by setting the bit of the start flag in the header part to “1” and the bit of the end flag to “0”. To do.

  In the child device S2, when the voice packet AP ′ (2) transmitted from the relay device R is received by the receiving unit 28, the child device control unit 26 acquires the voice data from the voice packet AP ′ (2) and receives the voice decoder. The video packet VP1 (2), VP2 (2), VP3 stored in the memory is detected by detecting that the transmission right is given by the transmission start command included in the audio packet AP ′ (2). (2) The voice packet AP (2) is transmitted from the transmitter 27. At this time, the slave unit control unit 26 sets the bit of the start flag in the header part of the packet (voice packet AP (2)) to be transmitted last to “0” and the bit of the end flag to “1”, thereby A transmission end command is transmitted by the packet AP (2).

  On the other hand, when the base unit M1 receives the video packets VP1 (1), VP2 (1), VP3 (1) and the voice packet AP (1) transmitted from the relay device R, the base unit control unit 7 Combines the video data acquired from the video packets VP1 (1), VP2 (1), and VP3 (1) to restore the original video data, and outputs the restored video data to the video decoder 5 for display 6 The audio data acquired from the audio packet AP (1) is expanded by the audio decoder 22, and the audio produced by the speaker (visitor) on the handset S1 side is caused to ring from the speaker 4. Further, when the transmission right is given from the relay device R by receiving the voice packet AP (1), the base unit control unit 7 causes the transmission unit 8 to transmit the voice packet AP ′ (1) stored in the memory. . At this time, the base unit control unit 7 transmits a transmission end command by the voice packet AP ′ (1) by setting the bit of the start flag in the header part to “0” and the bit of the end flag to “1”.

  When the video packet VP1 (2), VP2 (2), VP3 (2) and the voice packet AP (2) transmitted from the child device S2 are received by the first receiving unit 40, the signal processing unit of the relay device R In 44, it is detected that the transmission right is returned from the slave unit S2 by the transmission end command included in the voice packet AP (2). Further, the signal processing unit 44 changes the start flag bit in the header portion of the voice packet AP (2) to “1” and the end flag bit to “0” and causes the second transmission unit 43 to transmit the packet. AP (2) transmits a transmission start command to base unit M2.

  Further, when the voice packet AP ′ (1) transmitted from the parent device M1 is received by the second receiving unit 42, the signal processing unit 44 of the relay apparatus R transmits the transmission included in the voice packet AP ′ (1). It is detected that the transmission right is returned from the base unit M1 by the end command. Further, the signal processing unit 44 changes the start flag bit in the header portion of the audio packet AP ′ (1) to “1” and the end flag bit to “0”, and transmits the change from the first transmission unit 41, and transmits the audio packet AP ′ (1). A transmission start command is transmitted to the child device S1 by the packet AP ′ (1).

  Thereafter, by repeating the above-described operation, it is possible to perform a call using a combination of the slave unit S2 and the master unit M2 while performing a call using the combination of the slave unit S1 and the master unit M1.

  As described above, according to the present embodiment, the relay processing unit (signal processing unit 44) of the relay apparatus R transmits a packet including the transmission start command to the first and second transmission units 41 until an event for starting a call occurs. , 43 is not transmitted, the data transmission efficiency is not reduced as compared with the case of constant polling as in the conventional example. Moreover, when the event occurs, the relay processing means (signal processing unit 44) of the relay device R transmits a packet including a transmission start command from the first and second transmission units 41 and 43, and a plurality of slave units S1 and S2 Since the transmission right is given to the plurality of parent devices M1 and M2 in order, the child device S1 and the parent device can be avoided while avoiding collision of packets transmitted from the plurality of child devices S1 and S2 and the plurality of parent devices M1 and M2. M1 and a plurality of sets of the slave unit S2 and the master unit M2 can talk simultaneously. As a result, even in a system configuration in which a plurality of slave units S1 and S2 and master units M1 and M2 are branched and connected to a common transmission line Ls1 and Ls2 via a branching device B, collision is avoided without reducing transmission efficiency. Thus, it becomes possible to multiplex transmit audio (audio and video).

  By the way, in this embodiment, the transmission right is given from the relay apparatus R among the plurality of slave units S1 and S2 and the master units M1 and M2 branched and connected to the first and second transmission lines Ls1 and Ls2. Only one slave unit S1 or S2 and one master unit M1 or M2 can transmit packets, and the relay device R returns the transmission right from the slave units S1 and S2 and the master units M1 and M2. Only after the packet can be sent. Therefore, when a plurality of packets are continuously transmitted from the slave units S1 and S2, the master units M1 and M2, and the relay device R, the time during which the packets are transmitted from the slave units S1 and S2 or the master units M1 and M2 to the relay device R If a longer time interval is provided, a plurality of packets can be transmitted without collision. Note that the time during which a packet is transmitted from the slave units S1 and S2 or the master units M1 and M2 to the relay device R is the wiring length (first and second) from the slave units S1 and S2 or the master units M1 and M2 to the relay device R. 2) (the sum of the lengths of the transmission lines Ls1, Ls2 and the branch lines), and if the time interval is set longer than the transmission time calculated from the longest wiring length among the wiring lengths, Collisions can be reliably avoided when packets are transmitted continuously. Further, in the general CSMA system, there is a possibility that another packet may be transmitted during the time interval. For example, a packet is transmitted between the slave units S1 and S2 or the master units M1 and M2 and the relay device R. It is necessary to leave a time interval longer than the time for reciprocal transmission. On the other hand, in the present embodiment, since other packets are not transmitted within the above time interval, the time interval when continuously transmitting a plurality of packets is set to the slave units S1, S2 or the master units M1, M2. And the time required for a packet to be transmitted back and forth between the relay apparatus R and the relay apparatus R can be shortened.

  By the way, a plurality of packets including data of the same contents (the data may be a transmission start command or a transmission end command) between the relay device R and the slave units S1 and S2 and the master units M1 and M2. If data is transmitted continuously, data having the same contents can be transmitted reliably as compared with the case of transmitting one packet. For example, when a plurality of packets including a transmission start command and a transmission end command are continuously transmitted, data indicating the total number of transmissions and the order is included in the plurality of packets. Then, the reception side predicts the time for receiving the last packet based on the number of transmissions of the packet, and determines that a transmission start command or a transmission end command is received if the last packet is received by the predicted time. Even when the last packet cannot be received even after the predicted time has elapsed, it may be determined that the transmission start command or the transmission end command has been received.

  In the present embodiment, a wiring configuration is illustrated in which a plurality of slave units S1 and S2 are branched and connected to the first transmission line Ls1, and a plurality of master units M1 and M2 are branched and connected to the second transmission line Ls2. However, the technical idea of the present invention is applicable even when the slave units S1, S2 or the master units M1, M2 are connected in a star configuration to the first or second transmission lines Ls1, Ls2. It is clear that is applicable.

It is a system configuration figure showing an embodiment of the present invention. It is a time chart for operation | movement description same as the above. It is a time chart for operation | movement description same as the above.

Explanation of symbols

S1, S2 Slave unit M1, M2 Master unit R Relay device B Branching device Ls1 First transmission line Ls2 Second transmission line 1 Microphone (sound collecting means)
2 Voice encoder (data conversion means)
3. Audio decoder (digital / analog conversion means)
4 Speaker (sounding means)
7 Master unit control section (control means)
8 Transmitter (Transmission means)
9 Receiving part (receiving means)
20 Microphone (sound collecting means)
21 Voice encoder (data conversion means)
22 Voice decoder (digital / analog conversion means)
23 Speaker (ringing means)
26 Remote control unit (control means)
27 Transmitter (Transmitter)
28 Receiver (Receiver)
40 1st receiving part (1st communication means)
41 1st transmission part (1st communication means)
42 2nd receiving part (2nd communication means)
43 2nd transmission part (2nd communication means)
44 Signal processor (relay processing means)

Claims (6)

A plurality of slave units branch-connected to the first transmission line via branching units; a plurality of master units branch-connected to the second transmission line via branching units; and first and second And having a relay device connected to the transmission line without using a branching device,
The slave unit and the master unit include a sound collecting unit that collects a voice uttered by a speaker, a data conversion unit that converts voice collected by the sound collection unit into digital data, and voice data converted by the data conversion unit A transmission means for transmitting a packet including the first or second transmission line, a reception means for receiving a packet transmitted via the first or second transmission line, and a packet received by the reception means. Digital / analog conversion means for converting contained audio data into an analog audio signal; and sounding means for converting the sound signal output from the digital / analog conversion means into sound and ringing,
The relay device mutually transmits packets between the first communication means for transmitting packets to and from the slave unit via the first transmission line and to the master unit via the second transmission line. And a relay processing means for transmitting a packet received by the first communication means from the second communication means and transmitting a packet received by the second communication means from the first communication means. Prepared,
When an event for starting a call between any of the slave units and the master unit occurs, the relay processing means sends a packet including a transmission start command for giving a transmission right to the slave unit and the master unit to the first and The first and second communication means transmit one or more packets to be transmitted from the second communication means and before the transmission of the packet including the transmission start command to the child device and the parent device, respectively. ,
When the reception unit receives a packet including a transmission start command transmitted from the relay device, the slave unit transmits one or more packets including voice data converted by the data conversion unit from the transmission unit, and after transmitting the packet A control unit that causes the transmission unit to transmit a packet including a transmission end command for returning the transmission right to the relay device;
When the base unit receives the packet including the transmission start command transmitted from the relay device by the reception unit, the base unit transmits one or more packets including the voice data converted by the data conversion unit from the transmission unit, and after transmitting the packet A control unit that causes the transmission unit to transmit a packet including a transmission end command for returning the transmission right to the relay device;
The relay processing means of the relay device receives the packet including the transmission end command transmitted from the slave unit and the base unit by the first and second communication means and then receives the packet including the next transmission start command as the first and second packets. An intercom system, characterized by being transmitted from a communication means. The relay processing means of the relay device includes the transmission start command included in the packet containing the voice data, and causes the first and second communication means to transmit,
2. The interphone system according to claim 1, wherein the slave unit and the control unit of the master unit transmit the packet including voice data including the transmission end command from the transmission unit. When the relay processing means of the relay device transmits a plurality of packets from the first and second communication means, the plurality of packets are spaced with a time interval corresponding to the transmission line length to the destination slave unit and the base unit. Send
The slave unit and the control unit of the parent unit, when transmitting a plurality of packets from the transmission unit, transmit the plurality of packets with a time interval corresponding to the transmission line length to the relay device. The intercom system according to 1 or 2. The slave unit performs first transmission of an imaging unit that captures an image of the speaker, a video data conversion unit that converts video captured by the imaging unit into digital data, and a packet that includes video data converted by the video data conversion unit. The transmission means for transmitting via a track,
The master unit includes display means for displaying video, and video signal processing means for processing video data included in the packet received by the receiving means to display the video on the display means,
The relay processing unit of the relay device includes the transmission start command included in the packet including the video data and transmits the packet from the second communication unit,
2. The intercom system according to claim 1, wherein the control unit of the slave unit includes the transmission end command included in the packet including the video data from the transmission unit.   The intercom system according to any one of claims 1 to 4, wherein the transmission start command and the transmission end command include a flag included in a header of a packet. The relay processing means of the relay device continuously transmits a plurality of packets including the same content data from the first and second communication means,
The slave unit and the control unit of the master unit continuously transmit a plurality of packets including data of the same content from the transmission unit,
The intercom system according to any one of claims 1 to 5, wherein the data having the same content may include the transmission start command or the transmission end command.

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