Radio and wireless communication systems

Abstract

To provide a wireless device and a wireless communication system that enable a third party related to a caller to listen to audio received from another wireless device in full-duplex communication.SOLUTION: A wireless device 1A communicates audio data in frames of a predetermined length in full-duplex communication in which a transmission frequency and a reception frequency are different. The wireless device 1A includes: a storage unit 11 that stores audio data received by the wireless device 1A; a transmission control unit 183 that switches between a first mode in which first audio data based on audio picked up by a microphone 16 is transmitted and a second mode in which the stored audio data is transmitted as second audio data; and a timer management unit 186 that measures the time that the received audio data is stored in the first mode. The transmission control unit switches from the first mode to the second mode according to the measured time.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a radio and a wireless communication system. [Background technology]

[0002] A technology for transferring audio data received in a wireless communication system has been proposed. Document 1 describes how multiple audio signals are added together and transmitted in an analog radio. In addition, Patent Document 2 describes a commercial wireless system that performs half-duplex communication and a A transfer device for connecting to a mobile communication system that performs the above-mentioned operations is described. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6181892 [Patent Document 2] Patent No. 6183265 Summary of the Invention [Problem to be solved by the invention]

[0004] When full-duplex communication is performed using digital radio equipment, a third party may be able to listen to the conversation. There was a problem that it was difficult to listen to the first and second radios. When two parties are engaged in full-duplex communication, a third party connected to the caller using a third radio may The speech of the user using the first radio and the speech of the user using the second radio are both listened to. In full-duplex communication, it was difficult for the caller to receive the voice from the other radio. To provide a radio and a radio communication system that allow a third party having a relationship with the radio to listen in on the radio. [Means for solving the problem]

[0005] The present invention relates to a full-duplex communication system in which the transmission frequency and the reception frequency are different. A radio device that communicates voice data in units of long frames, a storage unit for storing first voice data based on a voice picked up by a microphone of the radio itself; a first mode for transmitting the stored voice data as second voice data; and a second mode for transmitting the stored voice data as second voice data. a transmission control unit for switching between a first mode and a second mode, and A timer management unit that measures the time stored in the memory, and the first mode is selected according to the measured time. The present invention provides a radio device which switches from the first mode to the second mode. Effect of the Invention

[0006] According to the present invention, in full-duplex communication, a voice signal received from another radio device is transmitted to a remote terminal that is not connected to the caller. It is possible to provide a radio and a radio communication system that can be listened to by a third party. do. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a configuration of a related wireless communication system. [Diagram 2] 2 is a schematic diagram showing an overview of the operation of the wireless device according to the first embodiment. FIG. [Diagram 3] 1 is a configuration diagram showing a configuration of a wireless communication system according to a first embodiment. [Figure 4] 1 is a configuration diagram showing a configuration of a wireless device 1A according to a first embodiment. [Diagram 5] 2 is a diagram showing a configuration of a wireless device 1B according to the first embodiment. FIG. [Figure 6] 1 is a schematic diagram showing an example of operation of a wireless communication system according to a first embodiment. [Figure 7]1 is a schematic diagram showing an example of operation of a wireless communication system according to a first embodiment. [Figure 8] 1 is a schematic diagram showing an example of operation of a wireless communication system according to a first embodiment. [Figure 9] 1 is a schematic diagram showing an example of operation of a wireless communication system according to a first embodiment. [Figure 10] 1 is a schematic diagram showing an example of operation of a wireless communication system according to a first embodiment. [Figure 11] FIG. 11 is a configuration diagram showing a configuration of a wireless device 1A according to a second embodiment. [Figure 12] 10 is a flowchart showing an operation of the wireless device according to the second embodiment. [Figure 13] 10 is a flowchart showing an operation of the wireless device according to the second embodiment. [Figure 14] 10 is a flowchart showing an operation of the wireless device according to the second embodiment. [Figure 15] FIG. 11 is a schematic diagram showing an example of operation of a wireless communication system according to a second embodiment. [Figure 16] FIG. 11 is a schematic diagram showing an example of operation of a wireless communication system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (Embodiment 1) First, the problems of the related wireless communication system will be described with reference to FIG. 1. FIG. 1 shows: 2 shows an overview of a related wireless communication system 200. The radios 2A, 2B, 2C and 2D are digital radio It is a line device that transmits voice data using a full duplex method with different transmission and reception frequencies. The full-duplex method is also called the full duplex method.

[0009] In the wireless communication system 200, a user UA of a wireless device 2A makes a query at a transmission frequency F1. The content of the inquiry is, for example, "Does anyone know anything about this?" The users of the wireless devices 2B, 2C, and 2D listen to the voice of the user UA.

[0010] Here, it is assumed that user UB of wireless device 2B responds to wireless device 2A on frequency f1. The frequency f1 is different from the frequency F1 transmitted by the wireless device 2A. The content is, for example, "I understand about this matter." When the wireless device 2A responds with "1", full-duplex communication is established between the wireless device 2A and the wireless device 2B. The users UC and UD of the wireless devices 2C and 2D circulate the communication between the wireless devices 2A and 2B. The intercepted signal is received at wave number F1. In other words, the users UC and UD are the query user UA and the response user UA. In such a case, the wireless device 2A becomes a third party with respect to communication with the activated user UB. The wireless devices 2C and 2D are called eavesdropping terminals. Also called.

[0011] Here, the users of the wireless devices 2C and 2D are eavesdropping on the frequency F1, so Therefore, user UA cannot hear the voice of user UB. If B's ​​response is not announced, users UC and UD may miss some of the information. There was.

[0012] Therefore, the inventor has determined that the initiator terminal transmits the voice A of the user UA and the voice B of the user UB. Here, voice A and voice B are encoded by a vocoder. It is a digital voice data compressed by a vocoder, which is used especially for business radio communication. It is not possible to mix audio A and audio B. The outline of the method will be explained below. When the voice A is interrupted, the initiator terminal receives the signal at frequency f1. In this case, the initiator terminal transmits voice A and voice B on frequency F1. Decodes the audio and detects when silence occurs. The decoded audio is, for example, PCM ( This is Pulse Code Modulation (PCM) data.

[0013] The initiator terminal stores the undecoded voice A and the received voice B in a buffer. Then, the initiator terminal starts transmitting the voice B at the timing when the voice A becomes silent. As a result, the initiator terminal transmits the transmission voice shown in FIG. When audio A is interrupted, audio B starts to be transmitted. The reason why audio A and audio B are stored in the same file is to prevent the beginning of the audio from being cut off.

[0014] Next, a configuration example of the wireless communication system 100 according to the first embodiment will be described with reference to FIG. The system configuration is the same as that shown in FIG. 1. The wireless communication system 100 includes a plurality of wireless devices 1. The wireless device 1A is the above-mentioned initiator terminal and transmits voice signals at a frequency F1. The wireless device 1B transmits a voice signal at a frequency f1 to the wireless device 1B and receives a voice signal at a frequency f2 from the wireless device 1B. The responder terminal described above receives voice A from the radio 1A at frequency F1 and The wireless devices 1C and 1D are the above-mentioned interceptor terminals, and are connected to the The number of interceptor terminals F1 receives voice A and voice B from the wireless device 1A. However, the number of eavesdropping terminals may be one, or three or more.

[0015] Audio A is also called the first audio data, and audio B is also called the second audio data. The devices 1A, 1B, 1C, and 1D communicate voice data in units of frames. What is a frame? A communication frame (a transmission frame, a reception frame) of a predetermined length determined by a communication format In the present invention, a communication frame with voice data is called a voice frame. The audio frame of audio A is called frame A, and the audio frame of audio B is called frame B. It's called Ream B.

[0016] 4 is a diagram showing the configuration of the wireless device 1A. The wireless device 1A includes a control unit 10, a storage unit 1 1, transmission modulation section 12, reception demodulation section 13, splitter 14, antenna 15, microphone 16, speaker It is equipped with a microphone 17, a voice control unit 18 and a vocoder 19.

[0017] The control unit 10 controls the transmission and reception of the wireless device 1A. The voice frame modulated by the transmission modulation unit 12 is output to the transmission modulation unit 12. The signal is transmitted from an antenna 15 via a splitter 14. The radio signal received by the input 15 is demodulated by the receiving demodulation unit 13, and frame B is output to the vocoder 19. To exert effort.

[0018] The vocoder 19 encodes the voice A picked up by the microphone 16 and outputs a voice frame of a predetermined length. The vocoder 19 also decodes the frame B demodulated by the reception demodulation unit 13. , and output to speaker 17.

[0019] The voice control unit 18 outputs frame A or frame B to the control unit 10 as a transmission frame. The voice control unit 18 includes a voice detection unit 181, a storage processing unit 182, a transmission control unit 183, and The voice detection unit 181 is also called a silence detection unit. decodes frame A encoded by vocoder 19 and detects silence in voice A. The voice detection unit 181 also decodes the frame B demodulated by the reception demodulation unit 13 and detects the voice B The voice detection unit 181 outputs the detection result of the silence to the transmission control unit 183. The storage processing unit 182 stores the frame B demodulated by the reception demodulation unit 13 in the storage unit 11. The storage unit 11 is a storage medium.

[0020] The transmission control unit 183 controls switching of the radio device 1A between the first mode and the second mode. The first mode is a mode for transmitting audio A, and the second mode is a mode for transmitting audio B. The transmission control unit 183 selects the first mode or the second mode according to the result of the silence detection by the voice detection unit 181. For example, when the transmission control unit 183 detects silence of the audio A, The transmission control unit 183 may also switch from the first mode to the second mode. When silence is detected and audio B is not silent, switch from mode 1 to mode 2. Here, the transmission control unit 183 may select the voice data stored in the frame where silence is detected. The transmission may be performed from the frame where silence was detected, and the frame stored in the predetermined number of frames before the frame where silence was detected may be transmitted from the frame where silence was detected. The transmission may start from audio data.

[0021] The difference between half-duplex and full-duplex communication is that half-duplex communication does not switch between sending and receiving. However, if user UA of wireless device 1A and user UB of wireless device 1B It is difficult to imagine a situation where users UA and UB always speak. To do this, one person might speak and the other listen. The following three cases are assumed: Case 1: Before one utterance ends, the other Case 2: At a certain moment, one of the speakers starts speaking (with overlap). Case 3: One utterance ends and the other begins (zero overlap). There is a period of time before one speaker speaks (there is a period of silence between the two speakers).

[0022] Here, case 2 is extremely rare, and most cases fall into case 1 or 3. Therefore, in case 1, we try to avoid cutting off the head as much as possible. It is important that user UA transmits voice B to the In order to recognize the speech of the user UB and terminate the speech, the wireless device 1A detects a silence frame. Therefore, silence detection can be used as a trigger to switch modes. It is considered appropriate to use

[0023] Returning to FIG. 4, the generation unit 184 A transmission frame is generated with a flag added for the purpose of transmitting the voice B to the wireless device 1B. In this case, feedback may occur. However, the user UB may find it difficult to have a conversation due to the output of the voice B. By transmitting a frame with a flag, the wireless device 1B receives the frame B. For example, the generation unit 184 may add a flag A to the frame A. and add flag B to frame B.

[0024] FIG. 5 is a diagram showing the configuration of the wireless device 1B. The audio control unit 18 of the wireless device 1B outputs The output control unit 185 controls the frame demodulated by the reception demodulation unit 13. Then, the output control unit 185 determines the flag that has been added according to the result of the determination. For example, when the output control unit 185 receives frame B, the output control unit 185 suppresses the audio output of frame B. When frame A is received, speaker 17 is muted. The wireless devices 1C and 1D may have the same configuration as the wireless device 1B. In addition, the output control unit 185 may not be provided.

[0025] Next, an operation example of the wireless communication system 100 according to the first embodiment will be described with reference to FIGS. 6 to 10 are diagrams showing transmission frames in the wireless devices 1A, 1B, 1C, and 1D. 1 is a schematic diagram illustrating an example of a frame transmitted by the wireless devices 1A and 1B and a received frame. It represents a time slot when communicating in frames. In other words, each time slot is 1 It corresponds to the time length of one frame.

[0026] First, FIG. 6 will be described. FIG. 6 shows a diagram of a wireless device 1A transmitting a voice A and a wireless device 1B transmitting a voice A. In this case, the transmission of voice B by radio unit 1A does not overlap with the transmission of voice B by radio unit 1A. The wireless device 1A transmits frames A1 and A2, and transmits silence frames at T3 to T5. Even if the device transitions to the second mode at T4, when it transmits a silence frame and receives frame B1, good.

[0027] The wireless device 1A receives frame B from the wireless device 1B after T4 and stores it in the memory unit 11. For example, the wireless device 1A stores B1 received at T4 in the memory unit 11 at T5. Then, the wireless device 1A transmits the stored frame B. For example, the wireless device 1A transmits the stored frame B at T5. The wireless device 1A transmits the frame B1 stored in the memory at T6. Frame B will be delayed by two frames due to storage and transmission processes. The wireless device 1A executes the storage process and the transmission process in one frame's worth of time slots. This is also fine.

[0028] In such a case, the wireless devices 1C and 1D receive frames A1 to A2 and frames B1 to B Here, the wireless device 1B can receive both the voice output of frames B1 to B5. The parentheses indicate that the audio output is to be suppressed.

[0029] Next, a description will be given of Fig. 7. Fig. 7 shows the transmission of voice A by the wireless device 1A and In this case, the overlap of the transmission of voice B by voice B is zero. Radio 1A transmits frames A1 and A2 on T1 and T2. Then, the wireless device 1A transmits a silence frame at T3 and also transmits frame B. For example, radio 1A detects a silence frame at T3 and transmits frame B. Alternatively, the control unit 10 may transition to a second mode in which the first mode is selected.

[0030] As in FIG. 6, the storage process and the transmission process cause a delay of two frames, so the wireless device 1A In this case, the wireless devices 1C and 1D also transmit B1 received at T3 at T5. Both frames A1 to A2 and frames B1 to B5 can be received. The transmitter 1B suppresses the audio output of frames B1 to B5.

[0031] Next, referring to FIG. 8 and FIG. 9, the transmission of voice A by the wireless device 1A and the We will now explain the case where there is an overlap in the transmission of audio B. The wireless device 1A transmits a frame A2, and the wireless device 1B transmits a frame B1. In this case, there is an overlap of one frame. The wireless device 1A transmits frames A2 to A5, and the wireless device 1B transmits frames B1 to B4. So in the case of Figure 9 there is an overlap of 4 frames.

[0032] In the case of FIG. 8, the wireless device 1A detects a silence frame at T3 and transitions to the second mode. As in Fig. 6 and Fig. 7, the storage process and transmission process cause a delay of two frames. 1A transmits B1, which it received at T2, at T4. At this time, wireless device 1A transmits a silence frame. In this case, the transmission is performed from the voice B1 stored in the radio 1. 1C and 1D can receive both frames A1-A2 and frames B1-B5. Moreover, the wireless device 1B suppresses the audio output of the frames B1 to B5.

[0033] In the case of FIG. 9, the wireless device 1A detects a silence frame at T6 and transitions to the second mode. Therefore, the wireless device 1A transmits frame B stored in the memory unit 11 from T7. do.

[0034] In FIG. 9, the wireless device 1A detects a silence frame and stores frame B4 at T6. The wireless device 1A starts transmission from frame B2, which is two frames before the previous frame. Alternatively, the transmission may start from the audio B stored in a predetermined number of frames before the audio frame. The number may be determined based on, for example, the storage capacity of the storage unit 11, an acceptable delay, and the like. In this case, the wireless devices 1C and 1D cannot receive the frame B1, but Frames A1 to A2 and frames B2 to B5 can be received.

[0035] The wireless device 1A may have an interrupt function that prioritizes the transmission of the audio A. The function is to transmit audio A when audio A is detected as being active in the second mode. FIG. 10 is a schematic diagram showing an overview of the operation of the wireless device 1A when the wireless device 1A has an interrupt function. .

[0036] The wireless device 1A transmits frames B1 to B3 at times T1 to T3. The wireless device 1A operates in the second mode from T1 to T3. At T6, audio A is detected and frames A1 to A3 are transmitted using the interrupt function. The interrupt by the function ends at T6, and wireless device 1A transmits the stored frame B from T7 onwards. do.

[0037] The effects of the present embodiment will be described below. The third party cannot hear the responder's voice in full-duplex communication. However, in order to superimpose voice A and voice B, There is a problem that the audio data is degraded when encoding and decoding with the same data. It is difficult for a receiving device to decode more than two types of audio, and even if it is decoded, the audio There were cases where playback was not possible.

[0038] The wireless device according to the first embodiment receives the first voice data of the initiator and the second voice data of the responder. Therefore, according to the first embodiment, the third party can transmit the respondent's The wireless device according to the first embodiment can also receive the second voice of the responder. A flag for identifying voice data is added to the voice frame. This suppresses the output of the second audio data, making it difficult to hear and reducing the occurrence of howling. Furthermore, the wireless device according to the first embodiment can select the first voice data in response to the detection result of silence. The timing of speech transmission is naturally switched in order to switch between the first voice data and the second voice data. It is possible.

[0039] (Embodiment 2) The wireless device according to the first embodiment switches between a first mode and a second mode depending on a result of detection of silence. The wireless device according to the second embodiment switches to the second voice data in the first mode. It has a timer that measures the time it takes to record data, and switches to the first mode depending on the timer measurement result. and the second mode.

[0040] The configuration of the wireless communication system 100 according to the second embodiment is the same as that shown in FIG. FIG. 11 is a diagram showing the configuration of a wireless device 1A according to the second embodiment. The following will mainly explain the points that differ from the first embodiment.

[0041] The voice control unit 18 includes a timer management unit 186. The timer management unit 186 is The time taken to record frame B in the memory unit 11 is measured and the time taken to record frame B in the memory unit 11 exceeds the set time of the timer. If the recording time exceeds the timer setting, the timer management unit 186 When the recording time exceeds the set time of the timer, an alarm sound is generated using the speaker 17. If so, the timer management section 186 notifies the transmission control section 183 to that effect.

[0042] The storage processing unit 182 stores the frame B demodulated by the reception demodulation unit 13 in the same manner as in the first embodiment. The voice B is stored in the memory unit 11. Here, the memory processing unit 182 stores the voice B in the first mode. The act of memorizing something is called recording. In other words, recording is the process of recording a conversation in which voice A and voice B overlap. In this case, audio B is stored.

[0043] The transmission control unit 183 switches between the first mode and the second mode in response to a notification from the timer management unit 186. In addition, the transmission control unit 183 switches between the notification from the timer management unit 186 and Alternatively, the mode may be switched based on both the detection result of silence by the voice detection unit 181 and the detection result of silence by the voice detection unit 181.

[0044] The timer management unit 186 may set the timer time to 0 ms. In this case, the transmission control unit 183 transitions to the second mode when receiving the voice B, and transmits the frame B In other words, the transmission of audio A is interrupted and audio B is transmitted.

[0045] The configuration of the radio device 1B according to the second embodiment is the same as that of the first embodiment, so the description will be omitted. The configurations of the wireless devices 1C and 1D according to the second embodiment are the same as those of the first embodiment. Therefore, the description will be omitted.

[0046] Next, the operation of the wireless device 1A will be described with reference to Figs. 12 and 13. The numbers "1" and "2" in the figure correspond to the numbers "1" and "2" in FIG. In this example, full-duplex communication is established between wireless device 1A and wireless device 1B. It is assumed that (step S101).

[0047] When full-duplex communication is established, the wireless device 1A starts transmitting audio A (S Step S102). Here, when the wireless device 1A transmits a voice A or silent frame, Next, the wireless device 1A detects voice B based on the received frame B. If the voice B is not detected (step S103), If the result is No in step S103, the process returns to step S103.

[0048] When the voice B is detected (Yes in step S103), the wireless device 1A It is determined whether or not the voice A is present (step S104). If the voice A is not detected (step S104 13), the wireless device 1A starts transmitting the audio B (step S105), and the “1” in FIG. In other words, if voice B is detected and voice A is not detected, the process starts from step 1. The transmitter 1A shifts from the first mode to the second mode and starts transmitting the voice B. The line terminal 1A may transmit a frame with flag B added.

[0049] When the voice A is detected (Yes in step S104), the wireless device 1A starts a timer. (Step S106), and start recording audio B (Step S107). The timer setting time in 6 may be 0 ms. Next, the radio device 1A sets the recording time It is determined whether the timer expires or not (step S108). If the call is being received (Yes in step S108), the wireless device 1A receives the call using the speaker 17. An alarm is sounded (step S109), and the transmission of the recorded voice B is started ( Step S111). That is, if the timer has expired, the wireless device 1A switches from the first mode to the Then, the mode shifts to the second mode and transmission of audio B begins.

[0050] If the timer has not expired (No in step S108), the wireless device 1A detects the voice A. If voice A is detected (step S110), the presence or absence of voice A is determined (step S110). If the voice A is not detected, the wireless device 1A returns to the determination process of step S108. (No in step S110), the wireless device 1A starts transmitting the recorded voice B (step In other words, even if the timer has not expired, the voice A is not detected. In this case, the wireless device 1A transitions from the first mode to the second mode and starts transmitting the audio B. This will be the case.

[0051] Next, FIG. 13 will be described. In step S105 or S111 in FIG. After starting the transmission of the voice B, the wireless device 1A judges whether the voice A is detected (step S2 01). When the wireless device 1A detects the voice A (Yes in step S201), the wireless device 1A turns on the speaker. 17 to sound an alarm (step S202). If the voice A is not detected in step S201 (No in step S201), or if After the alarm sound is sounded, it is determined whether or not sound B has been detected (step S203).

[0052] When the wireless device 1A detects the voice B (Yes in step S203), the wireless device 1A If the voice B is not detected (No in step S203), the wireless device 1A In other words, the wireless device 1A starts transmitting the voice B. If not detected, the mode changes from the second mode to the first mode and starts transmitting audio A. In step S201, when voice A is detected (Yes in step S201), the “ The process may be such that priority is given to audio A, for example, by transitioning to "audio A: 2."

[0053] Next, an example of the operation of the wireless device 1B will be described with reference to FIG. The operation is the same as that of the first embodiment. First, full-duplex communication is performed between the wireless device 1A and the wireless device 1B. It is assumed that a plex communication has been established (step S301). Based on the flag attached to the received frame, the received frame is determined to be frame A or frame B. In the case of frame A (step S302, Yes At step S303, the wireless device 1B unmutes the speaker. In the case of the radio device B (No in step S302), the radio device 1B mutes the speaker 17. (Step S304).

[0054] Next, the operation of the wireless communication system according to the second embodiment will be described with reference to FIGS. 15 and 16. The timer setting is assumed to be for four frames. In this case, the wireless device 1A transmits the frame A3 and receives the frame B1. The line device 1A sets a timer and starts recording the voice B. Here, the timer counts At T4, the wireless device 1A receives frame B2, so the timer count At T5, the radio 1A detects a silence frame and starts the timer count. The timer is stopped at 3. Radio 1A starts transmitting the recorded frame B from T6. do.

[0055] At T3 in FIG. 16, the wireless device 1A transmits a frame A3 and receives a frame B1. Therefore, the wireless device 1A sets the timer and starts recording the voice B, as in FIG. At T4 to T6, the wireless device 1A receives frames B2 to B4. Therefore, the timer count increases from T4 to T6, and the timer expires at T6. Therefore, the wireless device 1A transmits the stored voice B from T7. The third party listens to the audio B from the first frame B1 using the radios 1C and 1D. It is possible.

[0056] The wireless device according to the second embodiment determines whether to transmit voice A or voice B based on the recording time of voice B. By appropriately setting the timer, the wireless device according to the second embodiment can 1A transmits audio B without cutting off the beginning even when audio A and B overlap. can be done. [Explanation of symbols]

[0057] 1, 1A~1D radio 10 Control section 11 Storage section 12 Transmission Modulation Section 13 Reception demodulation section 14 Duplexer 15 Antenna 16. Mike 17 Speaker 18 Audio control section 19 Vocoder 181 Voice detection unit 182 Memory Processing Unit 183 Transmission control section 184 Generation part 185 Output control section 186 Timer Management Unit

Claims

[Claim 1] In full-duplex communication where the transmission frequency and the reception frequency are different, a frame of a given length is A wireless device that communicates voice data in units of a radio, A storage unit for storing voice data received by the radio device itself; a first mode in which first voice data based on a voice picked up by a microphone of the own radio is transmitted; A transmission mode for switching between a first mode and a second mode for transmitting the stored voice data as second voice data. A signal control unit; In the first mode, a timer is provided to measure the time for which the received voice data is stored. With the Department of Science, Equipped with The transmission control unit switching from the first mode to the second mode in response to the measured time; A radio device characterized by:

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