JP4508097B2 - Transmission system - Google Patents

Description

  The present invention relates to a transmission system in which a plurality of terminal devices are connected by a signal line composed of a pair of pair lines, and an audio signal and a control signal are transmitted between the terminal devices via the signal line.

Conventionally, various transmission systems for transmitting different types of signals via a common signal line have been provided (see, for example, Patent Document 1). The conventional system described in Patent Literature 1 is a loudspeaker call system that transmits a voice signal between two arbitrary call terminals and makes a call, in which a plurality of call terminals are centered on a signal line made up of a pair of pair lines. A digital audio signal and a control signal are transmitted via a signal line between the telephone terminal and the central processing unit, connected to the processing unit, and a so-called ping-pong transmission method is used to prevent signal collision. The ping-pong transmission method is a method for transmitting a signal by switching the signal transmission direction of the signal line every several μs to several milliseconds.
Japanese Patent Laid-Open No. 11-4298

  However, when the audio signal and the control signal are transmitted by the ping-pong transmission method as in the conventional example described in Patent Document 1, there is a transmission period of the audio signal even when the audio signal is not transmitted. The transmission efficiency of the control signal decreases due to the narrow transmission period of the signal. Moreover, if the transmission period of the audio signal is increased for the purpose of increasing the number of channels, the transmission period of the control signal is further shortened. In the first place, since it is required to receive the audio signal while managing the arrival delay to the receiving side, there are many systems that try to perform reliable audio transmission by the time division multiplexing method. For this reason, it is an unavoidable problem to achieve both the multi-channel audio signal and the improvement in control signal transmission efficiency as described above.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transmission system that can achieve both multi-channel audio signals and improved transmission efficiency of control signals.

  In order to achieve the above object, a plurality of terminal devices are connected by a signal line made up of a pair of pair wires, and an audio signal and control are performed between these terminal devices via the signal line. In a transmission system for transmitting signals, each terminal device transmits audio signals by means of TDMA (Time Division Multiple Access) and control signal transmission by which control signals are transmitted by CSMA (Carrier Sense Multiple Access). And a control signal generating means for generating a control signal for notifying other terminal devices of the start and end of transmission of the audio signal by the audio signal transmitting means and transmitting the control signal from the control signal transmitting means. The beacon signal that sends a beacon signal to the signal line from when the terminal device transmits the control signal notifying the start of transmission until transmitting the control signal notifying the end of transmission. When the signal generator is connected to the signal line and each terminal device is not receiving the beacon signal, the control signal transmission means is permitted only to the control signal transmission means without allowing the voice signal transmission means to transmit the voice signal. And, when receiving a beacon signal, a transmission system that alternately switches between a voice signal transmission period that allows the voice signal transmission means to transmit a voice signal and a control signal transmission period that allows the control signal transmission means to transmit a control signal It is characterized by comprising switching means.

  According to a second aspect of the present invention, in the first aspect of the invention, the beacon signal generating device alternates between a first beacon signal indicating the start of an audio signal transmission period and a second beacon signal indicating the start of a control signal transmission period. It is characterized by being sent to.

  According to a third aspect of the present invention, in the first aspect of the invention, the beacon signal generation device adds information indicating a time length of a voice transmission signal transmission period to the beacon signal, and the transmission method switching means of each terminal device includes: The time length of the audio signal transmission period is adjusted based on the information.

  A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the audio signal transmission means is used sequentially from the time slot having the earliest time slot among the vacant time slots.

  According to a fifth aspect of the present invention, in each of the first to fourth aspects of the present invention, each terminal device outputs a microphone, a speaker, and voice collected by the microphone to the voice signal transmission means as a voice signal and transmits the voice signal. Call processing means for outputting the audio signal received from the means to the speaker, and notifying means for causing the speaker to sound a sound or message for notifying that the time slot is empty. Features.

  According to the first aspect of the present invention, when no terminal device transmits an audio signal, only the transmission of the control signal is performed, so that the transmission efficiency of the control signal can be improved. When transmitting an audio signal, since the audio signal transmission period and the control signal transmission period are alternately switched, the audio signal transmission period can be made relatively long to increase the number of audio signals.

  According to the invention of claim 2, since the start period of the audio signal transmission period and the control signal transmission period can be individually set by the first and second beacon signals, each transmission period can be adjusted freely.

  According to the invention of claim 3, the audio signal transmission period can be adjusted without sending the second beacon signal as in the invention of claim 2.

  According to the invention of claim 4, since it is not necessary to prepare time slots for the number of terminal devices constituting the system during the audio signal transmission period, the transmission efficiency is improved.

  According to the fifth aspect of the present invention, it is possible to easily determine whether the voice signal cannot be transmitted because the other terminal is busy or for other reasons (such as signal line disconnection or terminal device failure).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the transmission system of the present embodiment is configured by connecting a plurality of terminal devices 1 and a beacon signal generating device 2 to a signal line Ls composed of a pair of pair lines.

  Each terminal device 1 is connected to the microphone 10 and the speaker 11 via the microphone 10 and the speaker 11, the amplifier 12a for amplifying the output of the microphone 10, the amplifier 12b for amplifying the input to the speaker 11, and the amplifiers 12a and 12b. The call processing unit 13, the operation unit 14 which has operation buttons such as a call button and a response button, and outputs an operation signal when the operation button is operated, and the audio signal and the control signal via the signal line Ls. The signal transmission part 15 which performs transmission / reception of this, and reception of a beacon signal, and the control part 16 which performs the whole control are comprised. The call processing unit 13 includes a voice switch and an echo canceller (not shown) to prevent howling and unpleasant echoes, and also collects sound by the microphone 10 and is amplified by the amplifier 12a (speech signal). Is converted into a digital signal and output to the signal transmission unit 15, and a digital voice signal (received signal) received from the signal transmission unit 15 is converted into an analog signal, amplified by the amplifier 12b, and output to the speaker 11. . The control unit 16 includes a CPU as a main component, and starts / stops the call processing unit 13, performs various processes according to operation signals received from the operation unit 14 and control signals received by the signal transmission unit 15, and generates control signals. Do. Each terminal device 1 is assigned a unique identification code and stored in the control unit 16, and the individual terminal devices 1 can transmit and receive control signals and audio signals using the identification code. . The signal transmission unit 15 supports two types of transmission methods. That is, a CSMA (Carrier Sense Multiple Access) system is used for control signals, and a TDMA (Time Division Multiple Access) system is used for audio signals. However, the control signal transmission method may be any of the CSMA / CA method, the CSMA / CD method, or a method that obligates the receiving node to return an ACK in each method. In the present embodiment, the control unit 16, the signal transmission unit 15, and the call processing unit 13 constitute an audio signal transmission unit, and the control unit 16 and the signal transmission unit 15 comprise a control signal transmission unit and a transmission method switching unit. And the control unit 16 constitutes a control signal generating means. Here, the audio signal and the control signal are converted by the control unit 16 into a multi-level modulation method, for example, an ASK (Amplitude Shift Keying) method, an FSK (Frequency Shift Keying) method, or a PSK (Phase Shift Keying). The signal is modulated by a method or the like and transmitted from the signal transmission unit 15.

  On the other hand, the beacon signal generator 2 transmits a beacon signal generated by the beacon signal generator 20 and the beacon signal generator 20 to the signal line Ls and transmits / receives a control signal via the signal line Ls. And a control unit 22 that has a CPU as a main component and performs control signal generation, various processes according to the control signal, and the like. Here, the beacon signal is a signal for synchronization when transmitting a voice signal by the TDMA system, and is sent at the start of a TDMA section (voice signal transmission period) as shown in FIG. There are two types: a beacon signal B1 and a second beacon signal B2 transmitted at the start of the CSMA section (control signal transmission period). The beacon signal generation unit 20 uses the first beacon signal B1 and the second beacon signal. B2 is alternately generated at a predetermined interval and output to the signal transmission unit 21. However, although it is the predetermined interval, the time interval from the first beacon signal B1 to the second beacon signal B2 that defines the TDMA interval (voice signal transmission period) and the CSMA (control signal transmission period) are defined. The time interval from the second beacon signal B2 to the next first beacon signal B1 is not necessarily the same time length. In the TDMA section, N slots (total number of slots that is twice as many as N), each of which is 1 or more in the upstream and downstream directions, are set, and any two terminal apparatuses When a call is made between 1 and 1, voice signals are transmitted to each other by occupying uplink and downlink time slots one by one. Here, since the beacon signal generation unit 20 performs modulation using a modulation method having a low multi-level compared to the audio signal and the control signal, for example, the binary ASK method, the FSK method, or the PSK method, the audio signal As compared with the control signal, the noise resistance of the beacon signal is improved and each terminal device 1 can receive the signal reliably.

  Next, the operation of this embodiment will be described.

  FIG. 2 is an example in which the generation of each signal is represented in time series. In accordance with control signals Tx1, Tx2, and Tx3 respectively issued by voice terminals 1, 2, and 3 that want to apply for a call in a normal CSMA section, the other three designated voice terminals are controlled by control signals Rx1, Rx2, and Rx3, respectively. This indicates that three call pairs have been established as a result of time-out of the CSMA section. After the CSMA section expires, the first beacon signal B1 is issued and the TDMA period starts, and the three pairs of calls have a total of six slots (sending or receiving channels) with the voice signal to be transmitted. Make it. A second beacon signal B2 is emitted after a predetermined number of times M1 and a CSMA period starts. In this CSMA section, as an example (although it is not directly related to the present invention), a fire alarm sensor such as a fire detector or a security sensor such as a human body detector is allowed to transmit a sensor alert that is issued when an abnormality is detected. Has been. In the same CSMA section, the two pairs that had been talking with the control signals Tx1, Tx2, Rx1, and Rx2 so far wanted to continue talking, and only the third pair that was talking with the control signals Tx3 and Rx3. Is in contact with the end of the call. As a result of the time-out of the CSMA section, two sets of call pairs have been established. Therefore, after the time of the CSMA section time-out, the first beacon signal B1 is issued again to start the TDMA section, and two sets of call pairs. Puts the audio signal to be transmitted in a total of four slots (transmission or reception channel). A second beacon signal B2 is issued after a predetermined number M2 of TDMA cycles, and the CSMA period starts. In the same CSMA section, it is assumed that the two pairs having been in communication with the control signals Tx1, Tx2, Rx1, and Rx2 so far are also in contact with each other at the end of the call. As a result of the time-out of the same CSMA section, there is no longer a desired pair of calls, so that the first beacon signal B1 is not generated after the time-out of the same CSMA section. The device 2 returns the communication sequence state to the normal CSMA section (starting stage in FIG. 2).

  The above is a schematic description, and a more detailed operation procedure will be described below.

  In a state where no terminal device 1 is talking, the beacon signals B1 and B2 are not sent from the beacon signal generator 2 to the signal line Ls. Therefore, in each terminal device 1, the control unit 16 stops the call processing unit 13 and the amplifiers 12a and 12b so that no audio signal is transmitted. When a call button (not shown) of the operation unit 14 is operated and an operation signal is input to the control unit 16 in any of the terminal devices 1 (hereinafter referred to as “1A”), the counterpart terminal device A control signal including an identification code corresponding to 1 (hereinafter referred to as “1B”) and its own identification code is generated by the control unit 16 and transmitted from the signal transmission unit 15 to the signal line Ls. In addition, as a method for specifying the terminal device 1B of the other party (calling destination), a plurality of call buttons corresponding to individual terminal devices 1 (other than 1A and 1B are referred to as “1C” and “1D”) are operated. 14 or by operating a numeric keypad provided in the operation unit 14 to directly input an identification code assigned to the terminal device 1B to be called.

  On the other hand, the terminal devices 1B, 1C, 1D,... Other than the terminal device 1A that sent the control signal receive the control signal transmitted through the signal line Ls by the signal transmission unit 15, and the control unit 16 performs the control. If the identification code included in the signal does not match the identification code of its own, it is discarded, and if it matches, a process of ringing a ringing tone from the speaker 11 via the amplifier 12b is performed. When a response button (not shown) of the called terminal device 1B is operated by a person who has heard the ringing tone, an operation signal is input from the operation unit 14 to the control unit 16 and corresponds to the calling terminal device 1A. And a control signal for notifying the call source terminal device 1A of the start of the call (voice signal transmission start) is generated by the control unit 16 and is transmitted from the signal transmission unit 15 to the signal line. Sent to Ls. Further, the control unit 16 activates the amplifiers 12a and 12b and the call processing unit 13 to prepare for the start of the call.

  In the calling terminal device 1A, the control signal transmitted via the signal line Ls is received by the signal transmission unit 15, and if the identification code included in the control signal does not match the own identification code in the control unit 16. If discarded and matched, the control unit 16 activates the amplifiers 12a and 12b and the call processing unit 13.

  On the other hand, in the beacon signal generation device 2, when the control signal for notifying the start of transmission of the audio signal is received by the signal transmission unit 21, the control unit 22 activates the beacon signal generation unit 20 and first and second 2 beacon signals B1 and B2 are generated and transmitted from the signal transmission unit 21 to the signal line Ls (see FIG. 2). In the call source and call destination terminal devices 1A and 1B, when the signal transmission unit 15 receives the first beacon signal B1, the TDMA interval is started and synchronized with the first beacon signal B1 (the immediately preceding CSMA). The audio signal is transmitted from the signal transmission unit 21 using the uplink and downlink time slots that are set (only the number of pairs of the call requesting terminals generated in the section). The beacon signal generating device 2 transmits a control signal (a control signal meaning release of a time slot at the end of the call) for notifying the end of the call (end of transmission of the voice signal) from the call destination or caller terminal device 1A. In the meantime, the first and second beacon signals B1 and B2 are continuously sent alternately and periodically.

  Then, in order to end the call, for example, when a response button is operated on the caller terminal device 1A, an operation signal is input from the operation unit 14 to the control unit 16, and the identification code corresponding to the callee terminal device 1B and the self The control unit 16 generates a control signal (a control signal meaning that a time slot is released at the end of the call) for notifying the terminal device 1B of the call destination of the end of the call (end of transmission of the audio signal). Thus, the signal is transmitted from the signal processing unit 15 to the signal line Ls during the CSMA interval between the TDMA intervals. Further, the control unit 16 stops the amplifiers 12a and 12b and the call processing unit 13 to end the call.

  In the called terminal device 1B, the control signal transmitted through the signal line Ls (a control signal meaning that the time slot is released at the end of the call) is received by the signal transmission unit 15, and is included in the control signal by the control unit 16. If the identification code does not match with its own identification code, it is discarded, and if it matches, the control unit 16 stops the amplifiers 12a and 12b and the call processing unit 13 and ends the call. In the beacon signal generation device 2, when the control signal for notifying the end of transmission of the audio signal is received by the signal transmission unit 21, the control unit 22 stops the beacon signal generation unit 20.

  Next, a case where a call button is operated on another terminal device 1 (hereinafter referred to as “1C”) while the set of terminal devices 1A and 1B is talking will be described. When a call button (not shown) of the operation unit 14 is operated and an operation signal is input to the control unit 16, an identification code corresponding to a new call destination terminal device 1 (hereinafter referred to as "1D"). And a control signal including a self (new caller) identification code is generated by the control unit 16, and the signal transmission unit 15 transmits a signal line Ls to the CSMA period (control signal transmission period) synchronized with the second beacon signal B2. Sent out. Then, a ringing sound is generated from the speaker 11 in the new call destination terminal device 1D, and a response signal is operated so that a control signal for notifying the new call source terminal device 1C of the start of transmission of the voice signal is generated. When the reply is made, the second set for the newly entered call pair in the immediately following TDMA period between the new call source terminal device 1C that has received the control signal and the new call destination call device 1D. The audio signal is transmitted using the time slots.

  Here, when a call button is operated on another terminal device 1 in a state where all time slots (channels) are in use, the control unit 16 of the terminal device 1 can grasp that there is no empty time slot. Then, a sound or a message for notifying that the telephone call is desired and the telephone call desired by the own device cannot be performed is generated from the speaker 11 via the amplifier 12b. That is, in this embodiment, the control unit 16 constitutes a notification unit. In this way, if the sound or message for notifying that the time slot is not available is sounded from the speaker 11, the other terminal device 1 is busy as a cause of the failure to transmit the voice signal. It is possible to easily determine whether this is the other reason (disconnection of the signal line Ls or failure of the terminal device 1).

  In the present embodiment, since the start periods of the audio signal transmission period and the control signal transmission period are individually set using the first and second beacon signals B1 and B2, each transmission period can be freely adjusted. There is an advantage. However, if the time length of the voice signal transmission period is fixed, it is not necessary to send the second beacon signal B2 because the start timing of the following short-term CSMA can be independently determined by each terminal device 1. In addition, the time slots used by each terminal device 1 may be assigned to individual terminal devices 1 in advance, but if the control unit 16 uses the time slots in order from among the time slots that are free, Since there is no need to prepare time slots for the number of terminal devices 1 constituting the system, there is an advantage that transmission efficiency is improved. Furthermore, in the present embodiment, the terminal device 1 that includes the microphone 10 and the speaker 11 and can perform the voice call is illustrated, but the terminal device 1 that includes only the microphone or only the speaker may be used. Further, a disaster prevention sensor or a crime prevention sensor that does not have a reception function and can be issued only during the CSMA period may be connected to the signal line Ls. Here, in this embodiment, the time slot in the voice signal transmission period (TDMA section) is a slot that is twice as many as the total N of the downlink N slots. A plurality of time slot groups may be accommodated in each TDMA section.

  By the way, instead of determining the start of the control signal transmission period by the second beacon signal B2, that is, the end of the audio signal transmission period, the beacon signal (first beacon signal B1) for setting the start of the audio signal transmission period is used. It is also possible to add information indicating the time length of the voice transmission signal transmission period, and the transmission method switching means (control unit 16) of each terminal apparatus 1 can adjust the time length of the voice signal transmission period based on the information. is there. In this way, the audio signal transmission period can be adjusted only by the first beacon signal B1 without sending the second beacon signal B2.

  As described above, in this embodiment, when any terminal device 1 does not transmit an audio signal, only the transmission of the control signal by the CSMA method is performed, so that the transmission efficiency of the control signal can be improved. When the terminal device 1 transmits a voice signal by the TDMA system, the voice signal transmission period (TDMA period) and the control signal transmission period (CSMA period) are alternately switched. It is possible to increase the number of audio signals by relatively increasing the audio signal transmission period. In the present embodiment, a distributed system in which each terminal device 1 performs call control and time slot status monitoring by itself is illustrated. However, a parent device that collectively performs call control and time slot status monitoring is used. A centralized management system may be used in which each terminal device 1 is connected to the signal line Ls and inquires a call request or time slot status from the base unit. In this case, a beacon signal may be transmitted from the master unit instead of the beacon signal generator 2.

  In the present embodiment, the first and second beacon signals are generated at predetermined intervals and periodically. However, the present invention is not limited to this, and if the TDMA interval ends earlier, the second is increased by that amount. The beacon signal may be generated early, or if the end of the call can be communicated between the transmitting and receiving terminals by voice packet communication in the TDMA period, the second beacon signal and the CSMA period immediately after the second beacon signal are not generated. The state may be returned to the normal CSMA period.

  Here, as shown in FIG. 3, by simply connecting the connector of the functional module 108 to the connection port of the gate device 103, the power path and the information path of the functional module 108 can be secured at the same time. There is a wiring system that can be connected also to the gate device 103 and is excellent in workability. In this wiring system, one or a plurality of switch boxes 102 embedded and disposed at appropriate positions in a building are provided, and a power line 110 and an information line 111 that are wired in advance in a wall surface between the switch boxes 102 are sent and wired. At the same time, with respect to the switch box 102 at the starting end, the power line 110 drawn indoors through the main breaker MB and the branch breaker BB drawn into the wiring board 101, and the gateway 120 (router) to the external Internet network NT. And the information line 111 connected via the hub). The transmission system according to the present invention can be incorporated in such a wiring system. More specifically, if the terminal device 1 and the beacon signal generation device 2 according to the present invention are respectively connected to the gate device 103 as the function module 108 and the information line 111 is the signal line Ls which is the above-mentioned pair of pair lines. Good. As another connection form, the beacon signal generating device 2 or one terminal device 1 according to the present invention is connected to the gate device 103 as the function module 108 and is branched from the information line 111 as a local line. A terminal device group 1 according to the present invention may be connected to (also a pair of paired wires) as shown in FIG.

It is a system configuration figure showing an embodiment of the present invention. It is operation | movement explanatory drawing same as the above. It is a system configuration diagram of a wiring system using the same.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Terminal device 2 Beacon signal generator 13 Communication processing part 15 Signal transmission part 16 Control part 20 Beacon signal generation part 21 Signal transmission part 22 Control part Ls Signal line

Claims (5)

In a transmission system in which a plurality of terminal devices are connected by a signal line composed of a pair of pair lines, and a voice signal and a control signal are transmitted between the terminal devices via the signal line.
Each terminal apparatus includes an audio signal transmission unit that transmits an audio signal by a TDMA (Time Division Multiple Access) method, a control signal transmission unit that transmits a control signal by a CSMA (Carrier Sense Multiple Access) method, and an audio signal transmission unit. Control signal generating means for generating a control signal for notifying other terminal devices of the start and end of transmission of an audio signal and transmitting the control signal from the control signal transmitting means,
A beacon signal generator that sends a beacon signal to the signal line is connected to the signal line from the time when any terminal device transmits the control signal notifying the start of transmission until the transmission of the control signal notifying the end of transmission. ,
When each terminal device does not receive a beacon signal, it does not allow the audio signal transmission means to transmit the audio signal, but only allows the control signal transmission means to transmit the control signal and receives the beacon signal Comprises transmission system switching means for alternately switching between an audio signal transmission period for allowing the audio signal transmission means to transmit an audio signal and a control signal transmission period for allowing the control signal transmission means to transmit a control signal. Transmission system.   2. The transmission according to claim 1, wherein the beacon signal generation device alternately transmits a first beacon signal indicating the start of an audio signal transmission period and a second beacon signal indicating the start of a control signal transmission period. system. The beacon signal generator adds information indicating a time length of a voice transmission signal transmission period to the beacon signal,
The transmission system according to claim 1, wherein the transmission method switching means of each terminal device adjusts the time length of the audio signal transmission period based on the information.   The transmission system according to any one of claims 1 to 3, wherein the audio signal transmission means is used in order from the time slot having the earliest time slot among vacant time slots.   Each terminal device includes a microphone and a speaker, a voice processing unit that outputs the voice collected by the microphone to the voice signal transmission unit as a voice signal, and outputs a voice signal received from the voice signal transmission unit to the speaker, and a time slot. The transmission system according to any one of claims 1 to 4, further comprising notification means for causing a speaker to sound a sound or message for notifying that there is no available space.

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