JP4947295B2 - Transmission / reception device, data amount adjustment method, data amount adjustment program, and communication system - Google Patents

Description

  The present invention relates to, for example, a device that transmits and receives data through a serial interface such as a USB (Universal Serial Bus), a method for adjusting the amount of transmission data used in the device, and a program for adjusting the amount of transmission data executed by a computer of the device And a communication system configured to be connected through a serial interface.

  With the spread of IP (Internet Protocol) networks such as the Internet and intranets, so-called IP telephones that use VoIP (Voice over IP) technology to make voice calls over IP networks have begun to spread. This IP telephone is for transmitting and receiving a digitally encoded voice signal divided into packets at regular intervals. An IP telephone has an advantage that a long-distance telephone charge can be reduced by using an IP network with high line use efficiency.

  In order to make such an IP phone inexpensive and easy to use, Patent Document 1 discloses a technique relating to a personal computer with a handset for transmission and reception. The invention described in Patent Document 1 is configured by connecting a handset for transmission and reception to a personal computer connected to a communication line.

  In this case, the personal computer outputs voice data received via the communication line to the handset and includes a voice driver for outputting voice data from the handset to the communication line. The personal computer and the handset are connected by an RS-232C interface that is a serial interface.

  By using the invention described in Patent Document 1, it is possible to configure a high-function IP telephone by using a personal computer and a handset, and an inexpensive and easy-to-use IP telephone without using a dedicated IP telephone. The IP phone can be used easily.

In addition, said patent document 1 is as follows.
Japanese Patent Laid-Open No. 10-340181

  By the way, when the personal computer and the handset are connected by a serial interface and audio data and the like are transmitted and received between both devices as in the invention described in Patent Document 1 described above, clock signals used by both devices are transmitted and received. Since the data is not completely the same, there may be a case where the amount of data transmitted per predetermined unit time does not match the amount of received data.

  For example, as shown in FIG. 5, in a system in which a personal computer 100 and a handset 200 are connected by a USB that is a serial interface and audio data and the like can be transmitted and received between both devices, the audio data is transmitted from the personal computer 100, Consider a case where this is received by the handset 200.

  The personal computer 100 includes an audio driver 101 that operates based on a clock signal supplied from a clock generator 103 and a USB interface (hereinafter abbreviated as USB I / F) 102. The personal computer 100 receives the packetized audio data transmitted via the communication network, disassembles the packet in the audio driver 101, and this is a USB interface (hereinafter abbreviated as USB I / F) 102. To supply. In the USB I / F 102, the audio data supplied thereto is transmitted with an SOF (Start of Frame) as a synchronization frame added every 1 ms (milliseconds) as shown in FIG. 5A. Yes.

  On the other hand, the handset 200 includes a USB I / F 201 that operates based on a clock signal supplied from the clock generator 203 and a codec 202. In the handset 200, the audio data from the personal computer 100 is received through the USB I / F 201 and stored in the buffer memory 202M of the codec 202. The codec 202 sequentially stores the audio data stored in the buffer memory 202M. Audio data for reproduction is formed, converted into an analog audio signal, and supplied to a receiver (not shown), so that audio corresponding to the audio data transmitted through the communication network is released from the receiver. To be sounded.

  However, as shown in FIG. 5, the personal computer 100 and the handset 200 each generate and use a clock signal. For this reason, the handset 200 generates a clock signal that provides the same timing as the clock signal used in the personal computer 100 for the audio data from the personal computer 100. Therefore, it is considered that there are cases where only 7 bytes of data to be detected in 8 frames in each frame can be detected, or conversely, 9 bytes are detected beyond the original frame.

  As described above, when the transmission data amount of data transmitted from the transmission-side device that should originally match does not match the reception data amount of data received at the reception-side device, audio data to be reproduced is lost. It may be a cause of inconveniences such as so-called sound interruptions or duplicated audio data to be reproduced, causing so-called sound delays.

  In addition, if the reception amount of audio data transmitted through the communication network in the personal computer 100 and the reproduction amount of audio data in the handset 200 are greatly separated, the transmitted audio data is appropriately transmitted through the handset 200. Since it cannot be played back at the processing speed, it is considered that a so-called voice delay may be generated and a natural call may not be possible.

  In view of the above, in the present invention, the amount of data transmitted from the own device and the amount of data received by the counterpart device are inconsistent in a device connected and connected via a serial interface. An object is to avoid inconveniences caused by matching.

In order to solve the above-described problem, the transmission / reception apparatus according to the first aspect of the present invention provides:
A transmission / reception device that transmits and receives data through a serial interface in which the amount of data transmitted per unit time is defined in the standard,
Clock generating means for generating a clock signal for determining the unit time;
Detecting means for detecting the amount of received data per unit time determined by the clock signal from the clock signal generating means for the received data transmitted through the serial interface and received by the own device;
Based on the received data amount detected by the detection means, the transmission data amount per unit time determined by the clock signal from the clock signal generation means for transmission data to be transmitted to the counterpart device through the serial interface. And determining means for determining by the above.

  According to the transmitting / receiving apparatus of the first aspect of the present invention, data is transmitted / received through an interface in which the amount of data transmitted per unit time is determined. The amount of received data per unit time determined by the signal is detected. That is, it is detected how much data is transmitted (data is being processed) by the counterpart device in a unit time determined by the clock signal generated by the own device.

  Then, based on the received data amount detected by the detecting means, the determining means determines the transmission data amount of data to be transmitted per unit time determined by the clock signal from the own clock generating means. That is, the transmission data amount per unit time is determined according to the data processing amount of the counterpart device that is known from the received data amount, and the data is transmitted in accordance with this.

  As a result, the amount of transmission data per unit time can be determined according to the data processing amount per unit time based on the clock signal of the own device in the counterpart device. Thus, it is possible to prevent inconsistency between the received data amount of the data received by the counterpart device and to avoid a problem caused by the inconsistency of the data amount.

Moreover, the transmission / reception apparatus of the invention described in claim 2 is the transmission / reception apparatus of claim 1,
An acquisition means for acquiring a used capacity of a reception buffer of a counterpart device that transmits data through the serial interface;
The determination unit determines the transmission data amount in consideration of the use capacity of the reception buffer acquired by the acquisition unit.

  According to the transmission / reception apparatus according to the second aspect, the used capacity of the reception buffer for temporarily storing the reception data in the counterpart device is acquired through the acquisition unit. The amount of transmission data per unit time is determined by the determining means in consideration of the acquired usage amount of the reception buffer.

  As a result, the transmission data amount can be appropriately determined in consideration of the capacity of the reception buffer of the counterpart device. More specifically, the transmission data amount of data to be transmitted to the counterpart device can be determined so as to minimize the delay that occurs until the data transmitted from the own device is processed in the counterpart device. Is done. Therefore, when the data to be transmitted / received is audio data, so-called audio delay is not generated.

  According to the present invention, in a device that is connected by a serial interface and transmits / receives data, a transmission data amount of data transmitted from the own device and a reception data amount of data received by the counterpart device become inconsistent. The inconvenience which generate | occur | produces can be avoided.

  Hereinafter, embodiments of an apparatus, a method, a program, and a system according to the present invention will be described with reference to the drawings. In the embodiment described below, a personal computer 1 capable of connecting to the Internet and a handset 2 having a transmitter and a receiver for performing telephone communication are connected through a USB I / F. An example where the communication system according to the present invention is applied to an IP telephone communication system configured as described above will be described. In this case, the personal computer 1 is one to which the apparatus, method and program according to the present invention are applied.

[About system configuration and device configuration]
FIG. 1 is a block diagram for explaining an IP telephone communication system to which an embodiment of the present invention is applied. As shown in FIG. 1, in the communication system of this embodiment, a personal computer 1 and a handset 2 each have a USB I / F function and are connected via a USB I / F cable 3.

  Here, the USB I / F can transmit and receive data such as audio data in a unit of a frame every 1 ms, with a section in which data of 8 bytes (bytes) is transmitted in 1 ms (millisecond) as one frame. is there. In this case, the clock signal is not transmitted through the USB I / F. As the clock signal, one generated independently by the personal computer 1 and the handset 2 is used.

  As shown in FIG. 1, the personal computer 1 includes an audio driver 11, a USB I / F 12, a control unit 13, and a clock generator 14. The audio driver 11 performs packet decomposition on packetized audio data transmitted through the Internet, extracts audio data, and supplies the audio data to the USB I / F 12. Also, the audio driver 11 generates packetized audio data for transmission from the audio data to be transmitted supplied from the USB I / F 12, and sends this to the communication network.

  Note that packetized voice data transmitted / received through the Internet using the VoIP technology is transmitted / received in a relatively large unit in which, for example, one packet is 20 ms (milliseconds).

  The USB I / F 12 is supplied with the audio data received from the audio driver 11 and transmits it to the handset 2 in units of frames of 8 bytes / ms. The USB I / F 12 receives audio data in frame units from the handset 2 and supplies it to the audio driver 11.

  The control unit 13 controls each unit of the personal computer 1 such as the audio driver 11 and the USB I / F 12, and although not shown, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). A microcomputer configured by connecting a nonvolatile memory or the like through a CPU bus. The control unit 13 can also control supply of clock signals from the clock generator 14 formed using an oscillator such as a VCXO (Voltage Controlled Crystal Oscillator) to each unit.

  On the other hand, the handset 2 includes a USB I / F 21, a codec 22, a D / A converter 23, an amplifier 24, a receiver (speaker) 25, a transmitter (microphone) 26, an amplifier 27, an A / D converter 28, a control unit 29, a clock. A generator 30 is provided.

  The USB I / F 21 takes in audio data in units of 8 bytes / ms (frame units) from the personal computer 1 transmitted in units of frames and supplies the audio data to the codec 22. The USB I / F 21 receives audio data to be transmitted from the codec 22 and collects the audio data in units of 8 bytes / ms (frame units) and supplies the audio data to the personal computer 1.

  The codec 22 includes a buffer memory 22M used as a reception buffer, temporarily stores audio data from the personal computer 1 supplied through the USB I / F 21 in the buffer memory 22M, and decodes the audio data temporarily stored in the buffer memory 22 It is processed to form audio data for reproduction, and this is supplied to the D / A converter 23. In this case, the buffer memory 22M is used in a FIFO (First In First Out) system. The codec 22 receives the audio data to be transmitted from the A / D converter 28, encodes it, and supplies the encoded audio data to be transmitted to the USB I / F 21.

  The D / A converter 23 converts the audio data for reproduction from the codec 22 into an analog audio signal for reproduction, and supplies the analog audio signal to the receiver 25 through the amplifier 24. The amplifier 24 amplifies the level of the analog audio signal from the D / A converter 13, and the receiver 24 emits sound corresponding to the analog audio signal supplied thereto.

  The transmitter 26 collects voices generated by the user and converts them into electrical signals (analog voice signals), which are supplied to the A / D converter 28 through the amplifier 27. The amplifier 27 amplifies the analog audio signal from the transmitter 26, and the A / D converter 28 converts the analog audio signal from the amplifier 27 into a digital audio signal and supplies it to the codec 22. Is.

  The control unit 29 is a microcomputer that is connected through a CPU, ROM, RAM, and nonvolatile memory CPU bus (not shown). The control unit 29 can also control supply of clock signals from a clock generator 30 formed using an oscillator such as a VCXO (Voltage Controlled Crystal Oscillator) to each unit.

  Then, the packetized audio data addressed to the own device transmitted through the Internet is received by the personal computer 1 and decomposed by the audio driver 11 to extract the audio data, which is supplied to the USB I / F 12. The USB I / F 12 collects the audio data from the audio driver 11 in a frame unit of 8 bytes / ms and transmits it to the handset 2.

  The USB I / F 21 of the handset 2 receives and captures audio data in units of frames from the personal computer 1 and supplies it to the codec 22. The codec 22 temporarily stores the audio data from the USB I / F 21 in the buffer memory 22M, sequentially reads and decodes it, forms audio data for reproduction, and supplies this to the D / A converter 23.

  The D / A converter 23 converts the audio data for reproduction supplied thereto into an analog audio signal and supplies it to the receiver 25 through the amplifier 24. As a result, the voice corresponding to the packetized voice data addressed to the own machine transmitted through the Internet is emitted from the receiver 25.

  On the other hand, the voice such as the user's voice is collected by the transmitter 26, converted into an electrical signal here, amplified by the amplifier 27, and then supplied to the A / D converter 28. The A / D converter 28 converts the analog audio signal supplied thereto into a digital audio signal and supplies it to the codec 22.

  The codec 22 encodes the audio data from the A / D converter 28 to form audio data for transmission, and supplies this to the USB I / F 21. The USB I / F 21 collects the audio data from the codec 22 in a frame unit of 8 bytes / ms and transmits it to the personal computer 1.

  The USB I / F 12 of the personal computer 1 receives and captures audio data in units of frames from the handset 2 and supplies this to the audio driver 11. The audio driver 11 forms transmission data packetized in order to transmit the audio data for transmission from the USB I / F 12 to the Internet, and transmits this to the Internet.

  In this manner, the personal computer 1 and the handset 2 constitute an IP telephone, and voice communication can be performed via the Internet to perform telephone communication (call).

  By the way, in the IP telephone communication system configured as shown in FIG. 1, the clock signal is not transmitted through the USB I / F, and the clock signal generated independently by the personal computer 1 and the handset 2 is used. ing. For this reason, an error occurs between the clock signals generated by both devices, and there may be a difference between the amount of data transmitted from the personal computer 1 and the amount of data received by the handset 2 that receives the data. Conceivable.

  However, even if an error between clock signals occurs between devices, a clock signal error does not occur within the device because a common clock signal is used in the personal computer 1 and the handset 2. Therefore, in a predetermined unit time, the amount of audio data received and reproduced through the USB I / F 21 in the handset 2 and the audio data collected through the transmitter and transmitted to the personal computer 1 through the USB I / F 21 Is equal to the amount of data.

  Therefore, the personal computer 1 according to this embodiment detects the amount of received data per unit time of the audio data transmitted from the handset 2, and the unit to be transmitted from the own device to the handset 2 according to the amount of received data. By adjusting the transmission data amount of the audio data per time, the transmission data amount transmitted from the personal computer 1 and the reception data amount in the handset 2 that receives the data are not shifted. The unit time in this embodiment is one frame period, that is, 1 ms.

  Furthermore, the personal computer 1 of this embodiment detects the usage capacity (how much used) of the buffer memory 22M for received data that the codec 22 of the handset 2 has through the USB I / F, and this buffer memory 22M The transmission data amount of the audio data is adjusted in consideration of the used capacity.

  The amount of audio data transmission data is adjusted in consideration of the capacity used in the buffer memory 22M. If the audio data to be properly reproduced is not stored in the buffer memory 22M of the handset 2, the audio data is reproduced. This is because the processing of reproducing audio data in the handset 2 is delayed as compared with the audio data received by the personal computer 1, and so-called audio delay is increased, which is not preferable.

  In this way, by adjusting the amount of data transmitted from the personal computer 1 to the handset 2 in consideration of the amount of data received from the handset 2 and the used capacity of the buffer memory 22M of the handset 2, so-called sound skipping, etc. It is possible to prevent inconvenience related to the reproduced sound and to perform a good telephone communication (call) while minimizing the sound delay.

[Transmission data amount adjustment function 1]
FIG. 2 is a diagram for explaining the transmission data amount adjustment function 1 included in the personal computer 1 of the IP telephone communication system according to this embodiment. This transmission data amount adjustment function 1 adjusts the data amount of data transmitted from the personal computer 1 to the handset 2 according to the data amount of data received from the handset 2 by the personal computer 1 through the USB I / F. .

  As shown in FIG. 2, the control unit 13 of the personal computer 1 includes a reception data amount detection unit 131 and a transmission data amount detection unit 132. As described above, data is transmitted and received between the USB I / F 12 of the personal computer 1 and the USB I / F 21 of the handset 2. First, the control unit 13 of the personal computer 1 The amount of received data (received data amount) within one frame of received data received from the personal computer 1 through the USB I / F 1 is detected.

  That is, as described above, between USB I / Fs, data is transmitted and received with a section in which 8 bytes of data are transmitted in 1 ms as one frame. For this reason, the reception data amount detection unit 131 of the control unit 13 of the personal computer 1 monitors the reception data from the handset 2 received by the USB I / F 12 based on the clock signal from the clock generator 14 and monitors one frame ( The amount of received data is detected for each interval of 1 ms).

  Here, when the received data amount detection unit 131 can detect only 7 bytes of data per frame, the clock signal used in the handset 2 is one frame more than the clock signal used in the personal computer 1. It can be seen that there is less 1 byte per hit. On the contrary, when the received data amount detection unit 131 detects 9 bytes of data per frame, the clock signal used in the handset 2 is 1 frame more than the clock signal used in the personal computer 1. It can be seen that there is 1 byte more per hit.

  Then, the reception data detection unit 131 notifies the transmission data determination unit 132 of the detected reception data amount per frame. The transmission data determination unit 132 determines the data amount (transmission data amount) to be transmitted from the personal computer 1 per frame based on the reception data amount per frame from the reception data detection unit 131, and for each frame. The USB I / F 12 is controlled so as to send data of the determined data amount.

  As a result, even if there is an error in the clock signal used between the personal computer 1 and the handset 2, the data amount per frame of data transmitted from the personal computer 1 to the hard disk 2 is adjusted, and the sound is interrupted. And inconveniences such as an interval between sounds can be prevented.

[Transmission data amount adjustment function 2]
FIG. 3 is a diagram for explaining the transmission data amount adjustment function 2 of the personal computer 1 of the IP telephone communication system according to this embodiment. With the transmission data amount adjustment function 1 described with reference to FIG. 2, the data amount of data transmitted from the personal computer 1 to the handset 2 and the data amount of data processed in the handset 2 can be made the same. It is possible to prevent inconvenience such as sound interruption.

  However, if data that should be transmitted 8 bytes per frame can only be transmitted, for example, only 7 bytes per frame, an appropriate amount of audio data cannot be stored in the buffer memory 22M of the codec 22 of the handset 2. It is considered that there is a case in which processing delay occurs in the handset 2 for the voice data received by the personal computer 1 and the voice data received by the personal computer 1 cannot be processed through the handset 2 at an appropriate timing.

  Therefore, the personal computer 1 of the IP telephone communication system according to this embodiment takes into consideration the capacity of the buffer memory (reception buffer memory) 22M of the codec 22 of the handset 2 and transmits data to be transmitted from the personal computer 1 to the handset 2. The received data amount adjustment function 2 for adjusting the amount of data is also provided.

  As shown in FIG. 3, the USB I / F 12 of the personal computer 1 includes, for example, a buffer memory 12M, and temporarily stores information indicating the used capacity of the buffer memory 22M of the codec 22 provided through the USB I / F 21 of the handset 2. To be able to. In this case, it is possible to grasp the free capacity of the buffer memory 22M of the handset 2 by receiving provision of information indicating the total storage capacity of the buffer memory 22M.

  Further, as shown in FIG. 3, the control unit 13 of the personal computer 2 includes a buffer usage amount detection unit 133 in addition to the reception data amount detection unit 131 and the transmission data amount determination unit 132. The buffer usage amount detection unit 133 can detect the usage capacity of the buffer memory 22M used in the codec 22 of the handset 2 according to information temporarily stored in the buffer memory 12M of the USB I / F 12.

  Then, the personal computer 1 of the IP telephone communication system according to the present embodiment acquires the used capacity of the buffer memory 22M of the codec 22 of the handset 2 for each frame of received data, for example, using the USB I / F 12 function. Is something that can be done. In this case, the USB I / F 21 of the handset 2 acquires the used capacity of the buffer memory 22M of the codec 22 for each frame in response to a request from the USB I / F 12 of the personal computer 1, for example, and notifies the personal computer 1 Is something that can be done.

  When the usage capacity of the buffer memory 22M from the handset 2 is notified from the handset 2, the USB I / F 12 of the personal computer 1 temporarily stores this in the buffer memory 12M included in the USB I / F 12, for example. Then, the buffer usage amount detection unit 133 of the control unit 13 detects the current usage capacity of the buffer memory 22M of the handset 2 and notifies the transmission data determination unit 132 of this.

  As described above, the transmission data amount determination unit 132 is also supplied with the reception data amount per frame in the own device from the reception data amount detection unit 131. The amount of transmission data is determined based on the amount of received data, and further, the amount of transmission data per frame of audio data transmitted from the personal computer 1 to the handset 2 is determined in consideration of the used capacity of the buffer memory 22M of the handset 2. Adjust and decide. Then, as described above, the control unit 13 controls the USB I / F 12 according to the determination result in the transmission data amount determination unit 132 and adjusts the transmission data amount per frame.

  Thereby, for example, when the received data amount per frame detected by the received data amount detector 131 is 7 bytes, but the used capacity of the buffer memory 22M of the handset 2 is less than half of the total storage capacity, Since there is still room in the usable capacity of the buffer memory 22M, the transmission data amount determination unit 132 can transmit more than the original transmission data amount, for example, 8 bytes per frame.

  Further, for example, when the received data amount per frame detected by the received data amount detection unit 131 is 9 bytes, but the used capacity of the buffer memory 22M of the handset 2 is 70% or more of the total storage capacity, Since the usable capacity of the buffer memory 22M is decreasing, the transmission data amount determination unit 132 can transmit 8 bytes per frame.

  As described above, the transmission data amount determination unit 132 generates inconvenience such as sound interruption based on the reception data amount per frame from the reception data amount detection unit 131 and the used capacity of the buffer memory of the handset 2. In addition, the data amount per frame of the audio data transmitted from the personal computer 1 is set so that the audio data received by the personal computer 1 can be processed at an appropriate timing in the handset 2 without causing an audio delay. I try to decide.

  Here, as described with reference to FIG. 3, the used capacity of the buffer memory 22M of the handset 2 is detected via the buffer memory 12M provided in the USB I / F 12 of the personal computer 1. It is not limited. Information such as the used capacity of the buffer memory 22M from the handset 2 is received via the USB I / F 12, supplied to the control unit 13, temporarily stored in a RAM or the like in the control unit 13, and used. Of course it is good.

[Transmission data amount adjustment processing]
By using the transmission data amount adjustment function 1 described with reference to FIG. 2, inconvenience such as so-called sound interruption can be prevented, and the transmission data amount adjustment function 2 described with reference to FIG. 3 is used. Thus, so-called audio delay can be prevented. That is, it is possible to prevent sound interruption or audio delay by using only one of the transmission data amount adjustment functions 1 and 2.

  However, in the personal computer 1 of the IP telephone communication system according to this embodiment, by using both the transmission data adjustment function 1 and the adjustment function 2 described above, it is possible to prevent sound interruption and voice delay. I am trying to support both. Hereinafter, the transmission data amount adjustment processing performed in the personal computer 1 of the IP telephone communication system of this embodiment will be described.

  FIG. 4 explains the transmission data amount adjustment processing performed in the personal computer 1 of this embodiment. The process shown in FIG. 4 is a process mainly executed in the control unit 13 when the personal computer 1 starts telephone communication in cooperation with the handset 2.

  First, the received data amount detection unit 131 of the control unit 13 detects the received data amount per unit time using a clock signal generated by the clock generator 14 of the own unit (step S1). As described above, the unit time used here is one frame period, that is, a period of 1 ms (millisecond).

  Next, the transmission data amount determination unit 132 of the control unit 13 should transmit per unit time so as to be the same as the reception data amount per unit time detected by the reception data amount detection unit 131 in step S1. The transmission data amount is determined, and the transmission data amount is adjusted (step S2). That is, the amount of data transmitted per 1 ms is set to be the same as the amount of audio data received from the handset 2.

  Thereafter, the buffer usage detection unit 133 of the control unit 13 monitors the used capacity of the buffer memory 22M of the codec 22 of the handset 2, detects the used capacity of the buffer memory 22M of the handset 2 at that time, This is supplied to the transmission data amount determination unit 132 (step S3).

  Then, the transmission data amount determination unit 132 determines whether or not the free space of the buffer memory 22 is small (whether or not the usage capacity is large) from the usage amount of the buffer memory 22M from the buffer usage amount detection unit 133 ( Step S4). As described above, by receiving the information indicating the total storage capacity of the buffer memory 22M from the handset 2, it is possible to accurately grasp the free capacity of the buffer memory 22M.

  When it is determined in the determination process in step S4 that the free space is large (the used capacity is small), the transmission data amount determination unit 132 increases the transmission data amount determined and adjusted in step S2. (Step S5). When it is determined in the determination process in step S4 that the free space is small (the used capacity is large), the transmission data amount determination unit 132 decreases the transmission data amount determined and adjusted in step S2. (Step S6).

  Note that how much the transmission data amount is increased in step S5 and how much the transmission data amount is decreased in step S6 are determined in advance according to, for example, the used capacity or the free capacity of the buffer memory 22M. You just have to keep it. In addition to the used capacity or free capacity of the buffer memory 22M, the amount of transmission data to be increased or the amount of transmission data to be decreased may be determined in consideration of the amount of transmission data determined in step S2. .

  In addition, when the available capacity of the buffer memory 22M of the handset 2 is limited to some extent, the amount of transmission data to be increased or the amount of transmission data to be decreased is incremented by 1 byte or by 2 bytes. It may be fixed in advance.

  Then, after the process of step S5 or after the process of step S6, data is transmitted from the personal computer 1 to the handset 2 in accordance with the adjusted transmission data amount. Then, the control unit 13 determines whether or not the call has ended (step S7), and when determining that the call has not ended, repeats the processing from step S1. If it is determined in step S7 that the call has ended, the process shown in FIG. 4 ends.

  As described above, in the personal computer 1 of this embodiment, the personal computer 1 is based on the received data amount per unit time of data transmitted from the handset 2 and received by the own device, and the used capacity of the buffer memory 22M of the handset 2. Since the amount of transmission data per unit time of data transmitted from the computer 1 to the handset 2 can be controlled, it is possible to prevent sound interruptions and voice delays.

  The functions of the reception data amount detection unit 131 and the transmission data amount determination unit 132 shown in FIGS. 2 and 3 and the function of the buffer usage amount detection unit 133 shown in FIG. 3 are executed by the control unit 13. It can also be realized by a program (software).

  Therefore, a program for performing the processing described with reference to FIG. 4 is created and provided to a personal computer to which the handset 2 is connected through a communication network such as the Internet, or a CD (Compact Disc) or DVD (Digital By providing a personal computer to which the handset 2 is connected using various recording media such as an optical disc such as a Versatile Disc, a function for appropriately adjusting the amount of transmission data can be later installed in various personal computers. it can.

  In the above-described embodiment, the case where the predetermined unit time is 1 ms (milliseconds) has been described as an example, but the present invention is not limited to this. For example, when data is transmitted / received through the USB I / F, a synchronization frame called SOF (Start Of Frame) is added to each packet, and the unit from SOF to the next SOF is defined as one unit section. The received data amount may be detected for each unit section, and the transmission data amount for each unit section may be adjusted accordingly. Of course, other appropriate time intervals can be used as the unit time.

  In the above-described embodiment, the case where the personal computer 1 and the handset 2 are connected through the USB I / F has been described as an example. However, the present invention is not limited to this. The present invention can be applied to the case where devices are connected through various serial interfaces in which the amount of data transmitted per unit time is defined according to the standard.

  In the above-described embodiment, the case where the present invention is applied to the IP telephone communication system has been described as an example. However, the present invention is not limited to this. That is, the data transmitted / received is not limited to voice data. The present invention can be applied to various communication systems that transmit and receive various data between at least two devices.

1 is a block diagram for explaining an IP telephone communication system to which an embodiment of the present invention is applied. FIG. It is a block diagram for demonstrating the adjustment function 1 of the transmission data amount which the personal computer 1 shown in FIG. 1 has. It is a block diagram for demonstrating the adjustment function 2 of the transmission data amount which the personal computer 1 shown in FIG. 1 has. 6 is a flowchart for explaining transmission data amount adjustment processing performed in the personal computer 1 shown in FIG. 1. It is a figure for demonstrating an example of the IP telephone communication system comprised with a personal computer and a handset.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Personal computer, 11 ... Audio | voice driver, 12 ... USB I / F, 13 ... Control part, 14 ... Clock generator, 131 ... Received data amount detection part, 132 ... Transmission data amount determination part, 133 ... Buffer usage amount detection part, 2 ... handset, 21 ... USB I / F, 22 ... codec, 22M ... buffer memory, 23 ... D / A converter, 24 ... amplifier, 25 ... receiver (speaker), 26 ... speaker (microphone), 27 ... amplifier, 28 ... A / D converter, 29 ... control unit, 30 ... clock generator

Claims (9)

A transmission / reception device that transmits and receives data through a serial interface in which the amount of data transmitted per unit time is defined in the standard,
Clock generating means for generating a clock signal for determining the unit time;
Detecting means for detecting the amount of received data per unit time determined by the clock signal from the clock signal generating means for the received data transmitted through the serial interface and received by the own device;
Based on the received data amount detected by the detection means, the transmission data amount per unit time determined by the clock signal from the clock signal generation means for transmission data to be transmitted to the counterpart device through the serial interface. A transmission / reception apparatus comprising: determination means for determining The transmission / reception device according to claim 1,
An acquisition means for acquiring a used capacity of a reception buffer of a counterpart device that transmits data through the serial interface;
The transmission / reception apparatus, wherein the determination unit determines the transmission data amount in consideration of a use capacity of the reception buffer acquired by the acquisition unit. A data amount adjustment method of transmission data in a transmission / reception apparatus that transmits and receives data through a serial interface in which a data amount transmitted per unit time is defined in the standard
A detection step of detecting the amount of received data per unit time determined by a clock signal from the clock signal generating means of the own device for received data transmitted through the serial interface and received by the own device;
Based on the received data amount detected in the detecting step, the transmitted data amount per unit time determined by the clock signal from the clock signal generating means for transmission data to be transmitted to the counterpart device through the serial interface. A data amount adjusting method comprising: a determining step for determining. The data amount adjustment method according to claim 3,
An acquisition step of acquiring a used capacity of a reception buffer of a counterpart device that transmits data through the serial interface;
In the determination step, the transmission data amount is determined in consideration of the use capacity of the reception buffer acquired in the acquisition step. A data amount adjustment program for transmission data executed by a computer installed in a transmission / reception device that transmits and receives data through a serial interface in which the amount of data transmitted per unit time is defined in the standard,
A detection step of detecting the amount of received data per unit time determined by a clock signal from the clock signal generation unit of the own device for received data transmitted through the serial interface and received through the interface unit of the own device;
The transmission data amount per unit time determined by the clock signal from the clock signal generation unit of the own machine for the transmission data transmitted to the counterpart device through the interface unit of the own machine and the serial interface is detected in the detection step. A computer-readable data amount adjustment program characterized by causing a determination step to be determined based on a received data amount. A data amount adjustment program according to claim 5,
The acquisition step of acquiring the used capacity of the reception buffer of the counterpart device that transmits data through the serial interface through the interface unit of the own device,
In the determination step, the transmission data amount is determined in consideration of the use capacity of the reception buffer acquired in the acquisition step. A communication system configured by connecting a first transmission / reception device and a second transmission / reception device through a serial interface in which a data amount transmitted per unit time is defined in the standard,
The first transmission / reception device includes:
Clock generating means for generating a clock signal for determining the unit time;
Detecting means for detecting the amount of received data per unit time determined by the clock signal from the clock signal generating means for the received data transmitted through the serial interface and received by the own device;
Based on the received data amount detected by the detection means, the transmission data amount per unit time determined by the clock signal from the clock signal generation means for transmission data to be transmitted to the counterpart device through the serial interface. And a deciding means for deciding the communication system. A communication system according to claim 7,
The first transmission / reception device includes:
An acquisition means for acquiring a used capacity of a reception buffer of a counterpart device that transmits data through the serial interface;
The determining means determines the transmission data amount in consideration of the used capacity of the reception buffer acquired by the acquiring means;
The second transmission / reception device includes:
A reception buffer for accumulating reception data transmitted from the first transmission / reception device through the serial interface;
And providing means for detecting the used capacity of the reception buffer and providing the detected capacity to the control device. A communication system according to claim 7 or claim 8, wherein
The first transmission / reception device includes:
Receiving means connected to a communication network and receiving voice data to be transmitted to the second transmitting / receiving device transmitted through the communication network;
Transmission means connected to the communication network and configured to transmit voice data transmitted from the second transmission / reception device to a target partner through the communication network;
The second transmission / reception device includes:
A handset for emitting sound according to the sound signal transmitted from the first transmitting / receiving device;
A communication system comprising: a transmitter that collects sound to be transmitted to the communication network via the first transmission device and converts the sound into an electrical signal.

Images