JP2015149667A - Relay device, and method and system for voice transmission/reception - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a relay device to provide an upper-level device with information including the state of an analog dedicated line through an ISDN circuit.SOLUTION: A relay device includes: a relay device-side voice transmitter unit 51; and a relay device-side voice receiver unit 52. The relay device-side voice transmitter unit 51 transmits, to a lower-level device 17, a remote control signal and a voice signal. The relay device-side voice receiver unit 52 receives a remote control signal and a voice signal from the low-level device 17, to transfer, through an ISDN line 3, data composed of a synchronous signal, the remote control signal and the voice signal through the upper-level device 13 to a control console 11. Among signals included in the remote control signal, which are incapable of thinning and capable of thinning, the signal capable of thinning is replaced by information in which the state of an analog dedicated line 5 is included, so as to transmit according to the synchronous signal.

Description

  The present invention relates to a relay apparatus, a voice transmission / reception method, and a voice transmission / reception system, and in particular, by using information signal bits, the relay apparatus transmits information including the status of an analog dedicated line to an upper apparatus via an ISDN line. The present invention relates to a relay device, a voice transmission / reception method, and a voice transmission / reception system that allow a control console to remotely monitor the status of an analog dedicated line by transmitting.

  Conventionally, the status of analog lines has been monitored. For example, there is one that determines whether or not an analog line is disconnected depending on the presence or absence of a pilot signal superimposed on the analog line (see, for example, Patent Document 1).

  In addition, there is a technique in which voice communication is performed while performing various data transmission by band-separating a voice signal, a control signal, a monitoring signal, and the like (see, for example, Patent Document 2).

  In addition, there has been a technique in which voice communication is performed smoothly by separating the frequency band of the audio signal and the control signal from the frequency band of the contact signal (see, for example, Patent Document 3).

  In addition, there is a B channel having a transmission rate of 64 kbps of an ISDN line divided into two parts of 32 kbps, and one of them is used for audio data encoded by ADPCM (Adaptive Differential PCM) (for example, Patent Document 4). reference).

  In addition, there is a case in which four speech channels are formed by dividing each B channel having a transmission rate of 64 kbps of an ISDN line into two, and a signal encoded by ADPCM having a transmission rate of 32 kbps is transmitted (for example, , See Patent Document 5).

  In some cases, data encoded by ADPCM and serial data are multiplexed and transmitted in one frame (for example, see Patent Document 6).

  In addition, there are some which transmit various signals by compressing the B channel in the ISDN line and allocating the D channel to the vacant area (see, for example, Patent Document 7).

  In addition, in the 2B + D channel structure of the ISDN line, four channels can be used by halving the two B channels, and in the case of voice communication, a voice signal encoded by ADPCM is inserted, and digital In the case of data communication, there is one in which digital data having a transmission rate of 32 kbps is inserted as it is (see, for example, Patent Document 8).

JP 2007-135053 A (paragraph [0020]) JP-A-8-18558 (paragraph [0017]) JP 2010-87705 A (paragraph [0053]) Japanese Patent Laid-Open No. 7-202834 (Claim 1) JP 7-131521 A (paragraph [0017]) JP-A-5-252315 (Claim 1) JP 7-154386 A (paragraph [0014]) JP 7-245774 A (paragraph [0013])

  Here, a control console, a host device, a relay device, and a lower device are provided, the host device and the relay device are connected by an ISDN line, the relay device and the lower device are connected by an analog dedicated line, and the control console is a lower device. Assume a system that remotely monitors the system.

  In the case of the system configuration assumed above, according to the conventional technology, the control console cannot remotely monitor the status of the analog dedicated line provided between the relay device and the lower-level device.

  In other words, in the prior art, it has been desired that the relay apparatus transmits information including the status of the analog dedicated line to the host apparatus via the ISDN line.

  The relay device of the present invention is applied to a voice transmission / reception system including a control console, a host device, and a lower device, and is provided between the host device and the lower device. The host device is an ISDN line. The lower device is a relay device connected by an analog leased line, and includes a relay device side voice transmitting unit and a relay device side voice receiving unit, and the relay device side voice transmitting unit is The remote operation signal and the audio signal are transmitted to the lower device, and the relay device side audio reception unit receives the remote operation signal and the audio signal from the lower device, The ISDN line transmits data composed of a synchronization signal, the remote operation signal, and the audio signal for each frame to the control console via the host device. While included in signal Among the non-signal and decimation possible signals can, replacing the decimation possible signal to information including the status of the analog dedicated line, and transmit in response to the synchronization signal.

  In the relay device according to the present invention, the relay device-side voice reception unit organizes the signal that can be thinned out, including a control signal transmitted to the lower device and a monitoring signal received from the lower device, and According to the state of the control signal and the state of the monitoring signal included in a possible signal, the line disconnection state of the analog dedicated line is detected as a first line disconnection, and the analog dedicated line is detected from the lower-level device. When a disconnection state detection result is received, it is detected as a second line disconnection and is transmitted to the control console including information on at least one of the first line disconnection and the second line disconnection.

  In the relay device according to the present invention, the relay device-side voice transmitting unit and the relay device-side voice receiving unit are set with a first frequency and a second frequency, and the control signal is turned on in the first state. Corresponding frequencies, the second frequency corresponding to the OFF state of the control signal, the first frequency corresponding to the ON state of the monitoring signal, and the second frequency corresponding to the OFF state of the monitoring signal. The relay apparatus-side voice receiving unit is configured so that the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are both less than a preset first threshold value. 1 is detected as a line disconnection.

  In the relay device of the present invention, the relay device-side voice receiving unit has a third frequency set, and the signal level corresponding to the control signal in the lower device is less than the first threshold set in advance. As a result of the determination, when the signal level corresponding to the third frequency is received from the lower-level device, and the signal level corresponding to the third frequency is equal to or higher than a second threshold set in advance, the second level Is detected as a line disconnection.

  In the relay device of the present invention, the relay device-side voice transmitting unit and the relay device-side voice receiving unit are configured such that the first frequency, the second frequency, and the third frequency are from a frequency band of the voice signal. A large frequency band is set, and a state different from the line disconnection state is set in the first frequency, the second frequency, and a fourth frequency band larger than the third frequency.

  In the relay device according to the present invention, the relay device-side voice transmission unit includes an oscillator that oscillates a signal level corresponding to each preset frequency, and the oscillator has the first signal when the control signal is in an ON state. The signal level corresponding to the second frequency is supplied to the lower order device, and when the control signal is in the OFF state, the signal level corresponding to the second frequency is supplied to the lower order device.

  In the relay device of the present invention, the relay device-side voice reception unit compares the signal level corresponding to each preset frequency with each of the first threshold value and the second threshold value. And when the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are both less than the first threshold, the level detection processing unit When the signal level corresponding to the third frequency is equal to or higher than the second threshold, it is detected as the second line disconnection.

  The voice transmission / reception method of the present invention is applied to a voice transmission / reception system including a control console, a higher-level device, and a lower-level device, and is provided between the higher-level device and the lower-level device. A voice transmission / reception method executed by a relay device connected by a line and the subordinate device being connected by an analog dedicated line, and for each frame on the ISDN line, a synchronization signal, a remote operation signal, The data composed of the audio signal is transmitted to the control console via the host device, and the remote operation signal and the sound signal are transmitted to the lower device, from the lower device. Receiving the remote operation signal and the audio signal, and among the non-thinable signal and the thinnable signal included in the remote control signal, the thinnable signal is the analog-only signal. Replaced with information including the status of the line, and transmit in response to the synchronization signal.

  In the voice transmission / reception method of the present invention, when the lower device detects a disconnection state of the analog dedicated line, the detection result is transmitted to the relay device, and a control signal transmitted to the lower device and received from the lower device. A signal that can be thinned out, including a monitoring signal, and depending on the state of the control signal and the state of the monitoring signal that are included in the signal that can be thinned, When detected as a first line break and the detection result of the line break state is received from the lower-level device, it is detected as a second line break and at least one of the first line break and the second line break Including the information on the information to be transmitted to the control console.

  In the voice transmission / reception method of the present invention, a first frequency and a second frequency are set, the first frequency corresponds to the ON state of the control signal, and the second frequency corresponds to the OFF state of the control signal. The frequency is associated, the first frequency is associated with the ON state of the monitoring signal, the second frequency is associated with the OFF state of the monitoring signal, the signal level corresponding to the first frequency and the first frequency When both of the signal levels corresponding to the frequency of 2 are less than a preset first threshold, it is detected as the first line disconnection.

  In the audio transmission / reception method of the present invention, when the third frequency is set and the signal level corresponding to the control signal is less than the preset first threshold, the signal level corresponding to the third frequency is set. When the signal level corresponding to the third frequency is transmitted to the relay device and is equal to or higher than a preset second threshold, it is detected as the second line disconnection.

  In the audio transmission / reception method of the present invention, the first frequency, the second frequency, and the third frequency are set to a frequency band larger than a frequency band of the audio signal, and the first frequency, the second frequency, And a state different from the line disconnection state are set in a fourth frequency band higher than the third frequency.

  In the audio transmission / reception method of the present invention, when the control signal is in an ON state, a signal level corresponding to the first frequency is supplied to the lower-level device, and when the control signal is in an OFF state, the signal level is set to the second frequency. A corresponding signal level is supplied to the subordinate device.

  In the voice transmission / reception method of the present invention, when both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than the first threshold, it is detected as the first line disconnection. When the signal level corresponding to the third frequency is equal to or higher than the second threshold, it is detected as the second line disconnection.

  The voice transmission / reception system of the present invention includes a control console, a host device, a relay device, and a lower device, the host device and the relay device are connected by an ISDN line, and the relay device and the lower device are connected to each other. An audio transmission / reception system connected via an analog leased line, wherein the relay device transmits a remote operation signal and an audio signal to the lower device, and the remote operation signal is transmitted from the lower device. The voice signal is received, and the ISDN line receives data composed of the synchronization signal, the remote operation signal, and the voice signal for each frame to the control console via the host device. Of the signals that are to be transmitted and cannot be thinned out and the signals that can be thinned out included in the remote operation signal, the thinnable signals are replaced with information including the status of the analog dedicated line It is intended to transmit in response to the synchronization signal.

  In the voice transmission / reception system of the present invention, when the lower order apparatus detects a disconnection state of the analog dedicated line in the lower order apparatus, the lower order apparatus transmits a detection result to the relay apparatus, and the relay apparatus transmits to the lower order apparatus. The control signal to be received and the monitoring signal received from the lower-level device are organized into the signals that can be thinned, and are included in the signals that can be thinned, depending on the state of the control signal and the state of the monitoring signal , Detecting the line disconnection state of the analog dedicated line as a first line disconnection, and detecting the line disconnection state detection result from the lower-level device, detecting the second line disconnection as the first line disconnection. And information related to at least one of the second line disconnections is transmitted to the control console.

  In the voice transmission / reception system of the present invention, the relay device is set with a first frequency and a second frequency, the control signal is made to correspond to the first frequency, and the control signal is turned off. Corresponding to the second frequency, corresponding the first frequency to the ON state of the monitoring signal, corresponding the second frequency to the OFF state of the monitoring signal, and corresponding to the first frequency. When both the signal level and the signal level corresponding to the second frequency are less than a preset first threshold, it is detected as the first line disconnection.

  In the voice transmission / reception system of the present invention, the lower device and the relay device are set with a third frequency, and the lower device has a signal level corresponding to the control signal that is less than the preset first threshold. If there is, the signal level corresponding to the third frequency is transmitted to the relay device, and the relay device has a signal level corresponding to the third frequency equal to or higher than a preset second threshold, The second line disconnection is detected.

  In the audio transmission / reception system of the present invention, the lower-level device and the relay device are set such that the first frequency, the second frequency, and the third frequency are larger than the frequency band of the audio signal, A state different from the line disconnection state is set in a fourth frequency band larger than the first frequency, the second frequency, and the third frequency.

  In the voice transmission / reception system of the present invention, the relay device includes an oscillator that oscillates a signal level corresponding to each preset frequency, and the oscillator has the first frequency when the control signal is in an ON state. A corresponding signal level is supplied to the lower order device, and when the control signal is in an OFF state, a signal level corresponding to the second frequency is supplied to the lower order device.

  In the voice transmission / reception system of the present invention, the relay device includes a level detection processing unit that compares a signal level corresponding to each preset frequency with each of the first threshold value and the second threshold value. The level detection processing unit detects that the first line is disconnected when both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than the first threshold. When the signal level corresponding to the third frequency is equal to or higher than the second threshold, it is detected as the second line disconnection.

  In the present invention, by using the information signal bit, the relay device transmits information including the status of the analog dedicated line to the host device via the ISDN line, so that the status of the analog dedicated line is remotely transmitted to the control console. It has the effect that it can be monitored from.

It is a figure which shows an example of a structure of the audio | voice transmission / reception system 1 used as the premise of Embodiment 1 of this invention. It is a figure which shows the example of each transmission function structure of the control console 11 and the high-order apparatus 13 which are contained in the audio | voice transmission / reception system 1 used as the premise of Embodiment 1 of this invention. It is a figure which shows each receiving function structural example of the control console 11 and the high-order apparatus 13 for reception which are contained in the audio | voice transmission / reception system 1 used as the premise of Embodiment 1 of this invention. It is a figure which shows the example of a transmission function structure of the relay apparatus 15 contained in the audio | voice transmission / reception system 1 used as the premise of Embodiment 1 of this invention. It is a figure which shows the example of a receiving function structure of the relay apparatus 15 contained in the audio | voice transmission / reception system 1 used as the premise of Embodiment 1 of this invention. It is a figure which shows each structural example of the transmission function of the low-order apparatus 17_1 contained in the audio | voice transmission / reception system 1 used as the premise of Embodiment 1 of this invention. It is a figure which shows the structural example of the communication frame transmitted / received by the audio | voice transmission / reception system 1 used as the premise of Embodiment 1 of this invention. It is a figure explaining an example of the frequency band of various signals used as the premise of Embodiment 1 of the present invention. It is a figure explaining the schematic structural example of the data format per frame applied when monitoring the state of the analog private line 5 contained in the voice transmission / reception system 1 in Embodiment 1 of this invention. It is a figure which shows an example of a structure of the audio | voice transmission / reception system 1 in Embodiment 1 of this invention. It is a figure which shows the example of a transmission function structure of the relay apparatus 15 contained in the audio | voice transmission / reception system 1 in Embodiment 1 of this invention. It is a figure which shows the example of a receiving function structure of the relay apparatus 15 contained in the audio | voice transmission / reception system 1 in Embodiment 1 of this invention. It is a figure which shows each structural example of the transmission function of the low-order apparatus 17 contained in the audio | voice transmission / reception system 1 in Embodiment 1 of this invention, and a reception function. It is a figure which shows the example of a receiving function structure of the high-order apparatus 13 contained in the audio | voice transmission / reception system 1 in Embodiment 1 of this invention. It is a figure explaining the schematic structural example of the data format applied when monitoring the state of the analog private line 5 contained in the audio | voice transmission / reception system 1 in Embodiment 1 of this invention corresponding with a frame number. It is a figure explaining the example of a schematic structure of the data format applied when monitoring the state of the analog private line 5 contained in the voice transmission / reception system 1 in Embodiment 1 of this invention in time series. It is a figure explaining an example of each frequency band of the control signal and monitoring signal in Embodiment 1 of this invention. It is a figure explaining an example of the frequency band corresponding to the line disconnection information detected by the low-order apparatus 17 in Embodiment 1 of this invention.

  Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
<Overview>
As will be described later, the voice transmission / reception system 1 uses the information signal bits, so that the relay device 15 transmits information including the status of the analog dedicated line 5 to the host device 13 via the ISDN line 3. The control console 11 remotely monitors the status of the analog private line 5.

<Description of prerequisite technology>
FIG. 1 is a diagram showing an example of a configuration of a voice transmission / reception system 1 which is a premise of Embodiment 1 of the present invention. As shown in FIG. 1, the voice transmission / reception system 1 includes a control console 11, a host device 13, a relay device 15, and a lower device 17_1 to a lower device 17_3. The host device 13 and the relay device 15 are connected by the ISDN line 3. Note that the lower devices 17_1 to 17_3 are referred to as the lower devices 17 unless particularly distinguished from each other.

  The voice transmission / reception system 1 performs data transmission via the ISDN line 3 between the higher-level device 13 and the relay device 15. For example, when the audio transmission / reception system 1 encodes an audio signal using ADPCM (Adaptive Differential PCM) and compresses the audio signal to 32 kbps and assigns the audio signal to the B1 channel and the B2 channel of the ISDN line 3, the audio signal is set to 3 channels and other than the audio signal The information signal bits are composed of 4 bits, and data transmission can be performed.

  For example, if one of the information signal bits is unused, the voice transmission / reception system 1 allocates three channels of the voice signal and three bits of the information signal bit to the B1 channel and the B2 channel of the ISDN line 3. Data transmission is being performed.

  The voice transmission / reception system 1 connects the relay device 15 and the lower level device 17_1 of CH1 by an analog dedicated line 5_1 to perform data transmission of voice signals and information signals. The voice transmission / reception system 1 connects the relay device 15 and the lower level device 17_2 of CH2 through an analog dedicated line 5_2 to perform data transmission of voice signals and information signals. The voice transmission / reception system 1 connects the relay device 15 and the lower level device 17_3 of CH3 by an analog dedicated line 5_3, and performs data transmission of voice signals and information signals.

  Note that the analog dedicated line 5_1 to the analog dedicated line 5_3 are referred to as the analog dedicated line 5 unless particularly distinguished from each other.

  From the above description, the relay device 15 is connected to the lower device 17 via the analog dedicated line 5 for each channel, and performs data transmission of voice signals and information signals.

  The voice transmission / reception system 1 can transmit data of the CH1 voice signal and the control signal from the higher-level device 13 to the voice transmission device 63 included in the lower-level device 17_1 by such a data transmission system. The voice transmission / reception system 1 can transmit the audio signal and control signal of CH2 from the higher level device 13 to the voice transmission device 73 included in the lower level device 17_2 by such a data transmission system. The voice transmission / reception system 1 can transmit the audio signal and control signal of CH3 from the higher level device 13 to the voice transmission device 83 included in the lower level device 17_3 by such a data transmission system.

  In other words, the audio transmission / reception system 1 can transmit data of the three channels of audio signals and control signals from the upper apparatus 13 to the lower apparatus 17 for each channel, and can control the lower apparatus 17 remotely.

  The voice transmission / reception system 1 can transmit data of the CH1 voice signal and the monitoring signal to the higher-level device 13 from the voice reception device 64 included in the lower-level device 17_1. The voice transmission / reception system 1 can transmit data of the CH2 voice signal and the monitoring signal to the higher level device 13 from the voice reception device 74 included in the lower level device 17_2. The audio transmission / reception system 1 can transmit data of the CH3 audio signal and the monitoring signal to the upper apparatus 13 from the audio receiving apparatus 84 included in the lower apparatus 17_3.

  That is, the voice transmission / reception system 1 can transmit data signals and monitoring signals of a total of three channels from the lower level device 17 for each channel to the higher level device 13 and can control the lower level device 17 remotely.

  Here, it is assumed that an audio signal, a control signal, and a monitoring signal are transmitted between the control console 11 and the host device 13. Specifically, among the audio signal, the control signal, and the monitoring signal, the audio signal is transmitted and received between, for example, the control console 11 and the host device 13. Of the audio signal, the control signal, and the monitoring signal, the control signal is transmitted from the control console 11 to the host device 13, for example. Of the audio signal, the control signal, and the monitoring signal, the monitoring signal is transmitted from the host device 13 to the control console 11, for example.

  The control console 11 will be described. As shown in FIG. 1, the control console 11 includes a control console side audio transmission unit 31 and a control console side audio reception unit 32. FIG. 2 is a diagram illustrating a transmission function configuration example of each of the control console 11 and the host device 13 included in the voice transmission / reception system 1 which is the premise of the first embodiment of the present invention. As shown in FIG. 2, the control console side voice transmission unit 31 includes a CH1 operation unit 101, a CH2 operation unit 102, a CH3 operation unit 103, a CH1 audio input unit 111, a CH2 audio input unit 112, and a CH3 use. The voice input unit 113 is provided.

  The CH1 operation unit 101 is a switch for controlling the voice transmission device 63 mounted on the CH1 subordinate device 17_1. When the CH1 operation unit 101 is in the ON state, a voice signal is transmitted by the voice transmission device 63. The CH2 operation unit 102 is a switch for controlling the voice transmission device 73 mounted on the CH2 subordinate device 17_2, and a voice signal is transmitted by the voice transmission device 73 when in the ON state. The CH3 operation unit 103 is a switch for controlling the voice transmission device 83 mounted in the CH3 subordinate device 17_3. When the CH3 operation unit 103 is in the ON state, a voice signal is transmitted by the voice transmission device 83.

  That is, the ON state information and the OFF state information of the CH1 operation unit 101, the CH2 operation unit 102, and the CH3 operation unit 103 are output as control signals by the control console 11 to the host device 13.

  The voice input unit 111 for CH1 converts the voice of the person who operates the control console 11 into an electrical signal using, for example, a microphone and inputs the voice signal into the voice transmission / reception system 1 as a voice signal. The input audio signal is output to another device by the audio transmission device 63 mounted on the lower device 17_1 of CH1. The CH2 voice input unit 112 converts the voice of the person who operates the control console 11 into an electrical signal using, for example, a microphone and inputs the voice signal into the voice transmission / reception system 1. The input audio signal is output to another apparatus by the audio transmitting apparatus 73 mounted on the CH2 subordinate apparatus 17_2. The voice input unit 113 for CH3 converts the voice of the person who operates the control console 11 into an electrical signal using, for example, a microphone and inputs the voice signal into the voice transmission / reception system 1 as a voice signal. The input audio signal is output to another device by the audio transmission device 83 mounted in the CH3 subordinate device 17_3.

  That is, the electrical electrical signal input from the audio input unit 111 to the audio input unit 113 is output as an audio signal by the control console 11 to the host device 13.

  FIG. 3 is a diagram illustrating a reception function configuration example of each of the control console 11 and the reception higher-level device 13 included in the voice transmission / reception system 1 which is the premise of the first embodiment of the present invention. As shown in FIG. 3, the control console side voice receiving unit 32 includes a CH1 monitoring signal display unit 141, a CH2 monitoring signal display unit 142, a CH3 monitoring signal display unit 143, a CH1 audio output unit 151, and a CH2 audio output. Unit 152 and an audio output unit 153 for CH3.

  The CH1 monitoring signal display unit 141 notifies the user of the control console 11 by lighting a display (not shown), for example, that the audio receiving device 64 mounted on the CH1 subordinate device 17_1 has received and detected the audio signal. . The CH2 monitoring signal display unit 142 notifies the user of the control console 11 by lighting of a display (not shown), for example, that the audio reception device 74 mounted on the CH2 subordinate device 17_2 has received and detected the audio signal. . The CH3 monitoring signal display unit 143 notifies the user of the control console 11 by lighting a display (not shown), for example, that the audio receiving device 84 mounted on the CH3 subordinate device 17_3 has received and detected the audio signal. .

  Here, the information output and displayed by each of the CH1 monitoring signal display unit 141 to CH3 monitoring signal display unit 143 is based on the monitoring signal received from the host device 13.

  The CH1 audio output unit 151 outputs an audio signal received from the outside by the audio receiving device 64 mounted on the CH1 subordinate device 17_1, for example, to a speaker or the like. The CH2 audio output unit 152 outputs an audio signal received from the outside by the audio receiving device 74 mounted on the CH2 subordinate device 17_2, for example, to a speaker or the like. The CH3 audio output unit 153 outputs an audio signal received from the outside by the audio receiving device 84 mounted on the CH3 subordinate device 17_3, for example, to a speaker or the like.

  That is, the audio signal output from the audio output unit 151 to the audio output unit 153 is an output of the audio signal received from the higher-level device 13.

  Next, the host device 13 will be described. As shown in FIG. 2 and FIG. 3, the higher level device 13 includes a higher level device side voice transmission unit 41 and a higher level device side voice reception unit 42. Among these, the higher-level apparatus side audio transmission unit 41 includes a control signal organization unit 121, a transmission audio signal processing unit 123, and an ISDN line driver unit 125, as shown in FIG.

  The control signal organization unit 121 receives the control signal of CH1, the control signal of CH2, and the control signal of CH3 from the control console 11, generates b0 bits to b2 bits in the B1 channel of the 2B + D ISDN line 3, and generates the ISDN line. Output to the driver unit 125.

  The transmission audio signal processing unit 123 includes a CODEC unit 131, a CODEC unit 133, a CODEC unit 135, an ADPCM conversion unit 132, an ADPCM conversion unit 134, and an ADPCM conversion unit 136.

  The CODEC unit 131 receives the CH1 transmission audio signal, which is an analog audio signal, from the control console 11, converts it into a digital audio signal, and outputs it to the ADPCM conversion unit 132. The CODEC unit 133 receives the CH2 transmission audio signal, which is an analog audio signal, from the control console 11, converts it into a digital audio signal, and outputs it to the ADPCM conversion unit 134. The CODEC unit 135 receives the CH3 transmission audio signal, which is an analog audio signal, from the control console 11, converts it to a digital audio signal, and outputs it to the ADPCM conversion unit 136.

  ADPCM conversion section 132 encodes the compressed audio signal of CH1, which is a digital audio signal, with ADPCM and gives it to b4 bit of B1 channel to b7 bit of B1 channel. The ADPCM conversion unit 134 assigns the CH2 transmission audio signal, which is a digital audio signal, encoded and compressed by ADPCM to the b0 bit of the B2 channel to the b3 bit of the B2 channel. ADPCM converting section 136 encodes the compressed audio signal of CH3, which is a digital audio signal, with ADPCM, and gives it to b4 bit of B2 channel to b7 bit of B2 channel.

  The ISDN line driver unit 125 configures a communication frame, which will be described later, with information assigned to the b0 bit of the B1 channel to the b7 bit of the B1 channel and information assigned to the b0 bit of the B2 channel to the b7 bit of the B2 channel. And output to the 2B + D ISDN line 3.

  As shown in FIG. 3, the upper apparatus side voice receiving unit 42 includes a monitoring signal distributing unit 161, a received voice signal processing unit 163, and an ISDN line receiver unit 165.

  The ISDN line receiver unit 165 receives communication frame configuration data, which will be described later, from the 2B + D ISDN line 3, information given to the b0 bit of the B1 channel to the b7 bit of the B1 channel, and the b0 bit to B2 of the B2 channel. The information given to the b7 bit of the channel is acquired.

  Of the acquired information, the ISDN line receiver unit 165 outputs the b0 bit of the B1 channel to the b2 bit of the B1 channel to the monitoring signal distribution unit 161. Of the acquired information, ISDN line receiver section 165 outputs B4 channel b4 bit to B7 channel b7 bit to ADPCM demodulation section 172. Of the acquired information, the ISDN line receiver unit 165 outputs the b2 bit of the B2 channel to the b3 bit of the B2 channel to the ADPCM demodulation unit 174. Of the acquired information, the ISDN line receiver unit 165 outputs the B2 channel b4 bit to the B2 channel b7 bit to the ADPCM demodulation unit 176.

  ADPCM demodulation section 172 demodulates the information given to b4 bit of B1 channel to b7 bit of B1 channel, and outputs it to CODEC section 171 as a received audio signal of CH1, which is a digital audio signal. The CODEC unit 171 converts the CH1 reception audio signal, which is a digital audio signal, into a CH1 reception audio signal, which is an analog signal, and outputs it to the control console 11.

  ADPCM demodulation section 174 demodulates the information given to b0 bit of B2 channel to b3 bit of B2 channel, and outputs it to CODEC section 173 as a received audio signal of CH2 which is a digital audio signal. The CODEC unit 173 converts the CH2 reception audio signal, which is a digital audio signal, into a CH2 reception audio signal, which is an analog signal, and outputs it to the control console 11.

  ADPCM demodulation section 176 demodulates the information given to b4 bit of B2 channel to b7 bit of B2 channel, and outputs it to CODEC section 175 as a received audio signal of CH3 which is a digital audio signal. The CODEC unit 175 converts the CH3 reception audio signal, which is a digital audio signal, into a CH3 reception audio signal, which is an analog signal, and outputs it to the control console 11.

  Next, the relay device 15 will be described. FIG. 4 is a diagram showing an example of a transmission function configuration of the relay device 15 included in the voice transmission / reception system 1 which is a premise of the first embodiment of the present invention. FIG. 5 is a diagram illustrating an example of a reception function configuration of the relay device 15 included in the voice transmission / reception system 1 which is a premise of the first embodiment of the present invention.

  As shown in FIG. 4 and FIG. 5, the relay device 15 includes a relay device side voice transmission unit 51 and a relay device side voice reception unit 52. As shown in FIG. 4, the repeater side voice transmission unit 51 includes an ISDN line receiver unit 181, a control signal distribution unit 182, a transmission voice signal processing unit 183, a CH1 FDM signal modulation unit 185, and a CH2 FDM signal modulation unit 186. And CH3 FDM signal modulator 187.

  The ISDN line receiver unit 181 receives communication frame data, which will be described later, from the 2B + D ISDN line 3, information given to the b0 bit of the B1 channel to the b7 bit of the B1 channel, and the b0 bit to B2 of the B2 channel. The information given to the b7 bit of the channel is acquired.

  Of the acquired information, the ISDN line receiver unit 181 outputs the b0 bit of the B1 channel to the b2 bit of the B1 channel to the control signal distribution unit 182. Of the acquired information, the ISDN line receiver unit 181 outputs the B1 channel b4 bit to the B1 channel b7 bit to the ADPCM demodulation unit 201 of the transmission voice signal processing unit 183. Of the acquired information, the ISDN line receiver unit 181 outputs the b0 bit of the B2 channel to the b3 bit of the B2 channel to the ADPCM demodulation unit 203 of the transmission voice signal processing unit 183. Of the acquired information, the ISDN line receiver unit 181 outputs the B2 channel b4 bit to the B2 channel b7 bit to the ADPCM demodulation unit 205 of the transmission voice signal processing unit 183.

  The control signal distributor 182 outputs the b0 bit of the B1 channel to the FDM signal modulator 185 of CH1 as the CH1 control signal. The control signal distributor 182 outputs the B1 channel b1 bit to the CH2 FDM signal modulator 186 as a CH2 control signal. The control signal distributor 182 outputs the B2 channel b2 bit to the CH3 FDM signal modulator 187 as the CH3 control signal.

  ADPCM demodulating section 201 demodulates the information given to b4 bit of B1 channel to b7 bit of B1 channel, and outputs it to CODEC section 202 as a CH1 transmission voice signal which is a digital voice signal. The CODEC unit 202 converts the CH1 transmission audio signal, which is a digital audio signal, into a CH1 transmission audio signal, which is an analog signal, and outputs it to the CH1 FDM signal modulation unit 185.

  ADPCM demodulating section 203 demodulates the information given to b0 bit of B2 channel to b3 bit of B2 channel, and outputs it to CODEC section 204 as a transmission audio signal of CH2, which is a digital audio signal. The CODEC unit 204 converts the CH2 transmission audio signal, which is a digital audio signal, into a CH2 transmission audio signal, which is an analog signal, and outputs it to the CH2 FDM signal modulation unit 186.

  ADPCM demodulating section 205 demodulates information given to b4 bit of B2 channel to b7 bit of B2 channel, and outputs it to CODEC section 206 as a transmission audio signal of CH3 which is a digital audio signal. The CODEC unit 206 converts the CH3 transmission audio signal, which is a digital audio signal, into a CH3 transmission audio signal, which is an analog signal, and outputs it to the CH3 FDM signal modulation unit 187.

  The CH1 FDM signal modulation section 185 includes a first OSC 211, an LPF 215, and an adder circuit. The first OSC 211 outputs a 2950 Hz signal when the CH1 control signal from the control signal distributor 182 is ON, and outputs a 2950 Hz signal when the CH1 control signal from the control signal distributor 182 is OFF. do not do. The frequency band output from the first OSC 211 is within the control signal band (ΔF2) in the frequency multiplexing method described later.

  The LPF 215 is a low-pass filter that allows the audio signal band (ΔF1) to pass and blocks the control signal band (ΔF2) in the frequency multiplexing method described later. Therefore, the transmission audio signal of CH1 output from the CODEC 202 passes through the LPF 215, so that the control signal band (ΔF2) is blocked. The FDM signal modulation unit 185 adds the analog CH1 control signal output from the first OSC 211 and the CH1 transmission audio signal that has passed through the LPF 215 by the addition circuit, thereby transmitting the frequency-multiplexed CH1. The audio signal and the CH1 control signal are output to the CH1 analog dedicated line 5_1.

  The CH2 FDM signal modulator 186 also performs the same processing, and outputs the frequency-multiplexed CH2 transmission voice signal and CH2 control signal to the CH2 analog dedicated line 5_2. The CH3 FDM signal modulator 187 also performs the same processing, and outputs the frequency-multiplexed CH3 transmission voice signal and CH3 control signal to the CH3 analog dedicated line 5_3.

  As shown in FIG. 5, the repeater side voice reception unit 52 includes a CH1 FDM signal demodulation unit 231, a CH2 FDM signal demodulation unit 232, a CH3 FDM signal demodulation unit 233, a monitoring signal organization unit 241, a received voice signal processing. Section 243 and an ISDN line driver section 245.

  The reception audio signal processing unit 243 includes a CODEC unit 271, a CODEC unit 273, a CODEC unit 275, an ADPCM conversion unit 272, an ADPCM conversion unit 274, and an ADPCM conversion unit 276.

  The CH1 FDM signal demodulator 231 includes a first BPF 251, an LPF 255, and a level detection processor 261. The CH1 FDM signal demodulator 231 inputs the CH1 received voice signal frequency-multiplexed from the CH1 analog dedicated line 5_1 and the CH1 monitoring signal to the first BPF 251 and the LPF 255.

  The first BPF 251 is a band pass filter that passes signals in a frequency band of 2900 Hz or more and less than 3000 Hz and blocks signals in other frequency bands, for example. Since the monitoring signal is received as a 2950 Hz signal in the ON state, the monitoring signal passes through the first BPF 251 and is output to the level detection processing unit 261.

  The level detection processing unit 261 monitors the analog signal level, and outputs an ON signal as a digital signal when the analog signal exceeds a certain signal level. The level detection processing unit 261 converts the monitoring signal of CH1 into a digital signal and outputs it to the monitoring signal organization unit 241.

  The LPF 255 is a low-pass filter similar to the LPF 215 built in the FDM signal modulation unit 185 of the relay apparatus side voice transmission unit 51, and passes the frequency band (ΔF1) of the frequency-multiplexed reception voice signal to monitor signals. This is a low-pass filter that blocks the band (ΔF2). By such filter processing, only the received audio signal of CH1 is limited, and the LPF 255 outputs the received audio signal of CH1 that is an analog signal to the CODEC unit 271.

  The CH2 FDM signal demodulator 232 performs the same processing, converts the CH2 monitoring signal into a digital signal, outputs the digital signal to the monitoring signal organization unit 241, and outputs the CH2 reception audio signal, which is an analog signal, to the CODEC unit 273. .

  The CH3 FDM signal demodulator 233 also performs the same processing, converts the CH3 monitoring signal into a digital signal, outputs the digital signal to the monitoring signal organization unit 241, and outputs the CH3 reception audio signal, which is an analog signal, to the CODEC unit 275. .

  The CODEC unit 271 receives the CH1 reception audio signal, which is an analog audio signal, from the CH1 FDM signal demodulation unit 231, converts it into a digital signal, and outputs the digital signal to the ADPCM conversion unit 272. The CODEC unit 273 receives the CH2 received audio signal, which is an analog audio signal, from the CH2 FDM signal modulation unit 232, converts the received audio signal into a digital signal, and outputs the digital signal to the ADPCM conversion unit 274. The CODEC unit 275 receives the CH3 reception audio signal, which is an analog audio signal, from the CH3 FDM signal modulation unit 233, converts the received audio signal into a digital signal, and outputs the digital signal to the ADPCM conversion unit 276.

  The ADPCM conversion unit 272 assigns the received audio signal of CH1, which is a digital audio signal, encoded by ADPCM and compressed to the b4 bit of the B1 channel to the b7 bit of the B1 channel. The ADPCM conversion unit 274 gives the CH2 received audio signal, which is a digital audio signal, encoded and compressed by ADPCM to the b0 bit of the B2 channel to the b3 bit of the B2 channel. ADPCM conversion section 276 assigns the compressed audio signal of CH3, which is a digital audio signal, encoded with ADPCM to b4 bit of B2 channel to b7 bit of B2 channel.

  The ISDN line driver unit 245 configures a communication frame configuration, which will be described later, with information given to the b0 bit of the B1 channel to the b7 bit of the B1 channel and information given to the b0 bit of the B2 channel to the b7 bit of the B2 channel. And output to the 2B + D ISDN line 3.

  As shown in FIGS. 4 and 5, the voice signal, the control signal, and the monitoring signal are transmitted between the host device 13 and the relay device 15 via the ISDN line 3 having a 2B + D configuration. Of the audio signal, the control signal, and the monitoring signal, the audio signal is transmitted and received between the higher-level device 13 and the relay device 15, for example. Of the audio signal, the control signal, and the monitoring signal, the control signal is transmitted from the higher level device 13 to the relay device 15, for example. Of the audio signal, the control signal, and the monitoring signal, the monitoring signal is transmitted from the relay device 15 to the higher-level device 13, for example.

  Next, the lower order device 17 will be described. FIG. 6 is a diagram illustrating a configuration example of each of the transmission function and the reception function of the lower-level device 17_1 included in the voice transmission / reception system 1 that is the premise of the first embodiment of the present invention. As illustrated in FIG. 6, the lower-level device 17_1 includes a lower-level device-side audio transmission unit 61, a lower-level device-side audio reception unit 62, an audio transmission device 63, and an audio reception device 64. Here, the lower apparatus 17_1 performs audio transmission / reception with the outside for CH1, the lower apparatus 17_2 performs audio transmission / reception with the outside for CH2, and the lower apparatus 17_3 performs audio transmission / reception with the outside for CH3. Assumes something.

  The CH1 FDM signal demodulation unit 281 includes a first BPF 291, a level detection processing unit 292, and an LPF 293. The CH1 FDM signal demodulator 281 inputs the CH1 transmission voice signal and the CH1 control signal frequency-multiplexed from the CH1 analog dedicated line 5_1 to the first BPF 291 and LPF 293, and outputs the output signal to the voice transmission device 63. Output to.

  The first BPF 291 is a band pass filter that passes signals in the frequency band of 2900 Hz or more and less than 3000 Hz and blocks signals in other frequency bands. Since the control signal is received as a 2950 Hz signal in the ON state, the control signal passes through the first BPF 291 and is output to the level detection processing unit 292.

  The level detection processing unit 292 monitors the analog signal level, and outputs an ON signal as a digital signal when the analog signal exceeds a certain signal level. The level detection processing unit 292 converts the CH1 control signal into a digital signal and outputs the digital signal to the voice transmission device 63.

  The LPF 293 is a low-pass filter that passes an audio signal band (ΔF1) described in a frequency multiplexing method, which will be described later, and blocks a control signal band (ΔF2). By such filter processing, the CH1 FDM signal demodulation unit 281 is limited to only the CH1 transmission voice signal, and outputs the CH1 reception voice signal, which is an analog signal, to the voice transmission device 63.

  The lower device side voice receiving unit 62 includes a CH1 FDM signal modulating unit 283, and the CH1 monitoring signal and the CH1 received voice signal are input from the voice receiving device 64, and the superimposed signal is the CH1 analog dedicated line. Output to 5_1.

  The audio receiving device 64 receives an audio signal from the outside, and outputs the received audio signal of CH1 that is an analog signal to the FDM signal modulation unit 283 of CH1. The audio receiver 64 outputs a CH1 monitoring signal notifying that an audio signal has been received from the outside to the FDM signal modulator 283 of CH1.

  The CH1 FDM signal modulation section 283 includes a first OSC 311 and an LPF 315. The first OSC 311 outputs a 2950 Hz signal when the CH1 monitoring signal from the voice receiver 64 is ON, and does not output a 2950 Hz signal when the CH1 control signal is OFF. The frequency band of the signal output from the first OSC 311 is within the monitoring signal band (ΔF2) described in the frequency multiplexing method described later.

  The LPF 315 is a low-pass filter similar to the LPF 293 built in the FDM signal demodulator 281 of the lower apparatus side audio transmitter 61 described above, and passes only the frequency band (ΔF1) of the received audio signal for frequency multiplexing. This is a low-pass filter that blocks the audio signal corresponding to the monitoring signal band (ΔF2) of the received audio signal.

  The analogized CH1 monitoring signal output from the first OSC 311 and the CH1 reception voice signal that has passed through the LPF 315 are added by an adder circuit, and the frequency-multiplexed CH1 reception voice signal and the CH1 monitoring signal are dedicated to analog use. Output to line 5_1. Note that the internal configurations of the low-order device 17_2 and the low-order device 17_3 are the same as those of the low-order device 17_1, and thus description thereof is omitted.

  Next, an example of a communication frame will be described. FIG. 7 is a diagram showing a configuration example of a communication frame transmitted / received in the voice transmission / reception system 1 which is a premise of the first embodiment of the present invention. As shown in FIG. 7, it is assumed that the communication frame is transmitted using the B1 channel and the B2 channel in the 2B + D ISDN line 3.

  Specifically, in the B1 channel, the control signal and the monitoring signal of CH1 are given to the b0 bit. In the B1 channel, the control signal and the monitoring signal of CH2 are given to the b1 bit. In the B1 channel, the control signal and the monitoring signal of CH3 are given to the b2 bit. In the B1 channel, the b4 to b7 bits are given as CH1 transmission audio signals encoded by ADPCM.

  That is, a signal other than the transmission voice signal described above, for example, a control signal and a monitoring signal, can be applied to the B1 channel by the amount compressed by encoding using ADPCM.

  In the B2 channel, the b2 to b3 bits are given a CH2 transmission audio signal as a signal encoded by ADPCM. In the B2 channel, the b4 bit to b7 bit are provided with a CH3 transmission audio signal as a signal encoded by ADPCM.

  Next, an audio signal, a control signal, and a monitoring signal will be described. The audio signal, the control signal, and the monitoring signal are transmitted between the relay device 15 and the lower device 17 via the analog dedicated line 5.

  For example, the audio signal of CH1 is transmitted and received between the relay device 15 and the lower device 17_1. The audio signal of CH2 is transmitted and received between the relay device 15 and the lower device 17_2. The audio signal of CH3 is transmitted and received between the relay device 15 and the lower device 17_3.

  For example, the control signal of CH1 is transmitted from the relay device 15 to the lower device 17_1. The control signal of CH2 is transmitted from the relay device 15 to the lower order device 17_2. The control signal of CH3 is transmitted from the relay device 15 to the lower device 17_3.

  For example, the monitoring signal of CH1 is transmitted from the lower apparatus 17_1 to the relay apparatus 15. The monitoring signal of CH2 is transmitted from the lower order device 17_2 to the relay device 15. The monitoring signal of CH3 is transmitted from the lower apparatus 17_3 to the relay apparatus 15.

  Next, transmission of audio signals, control signals, and monitoring signals by frequency multiplexing will be described. FIG. 8 is a diagram for explaining an example of frequency bands of various signals that are the premise of the first embodiment of the present invention. As shown in FIG. 8, the audio signal band (ΔF1) is assigned a low-frequency band, for example, a band of 2700 Hz. On the other hand, the control signal band and the monitoring signal band (ΔF2) are assigned a frequency band higher than the audio signal band (ΔF1), for example, 2800 Hz or more. For example, a frequency of 2950 Hz is assigned to the control signal or the monitoring signal.

  As described above, when a signal is transmitted through the analog dedicated line 5, a frequency band corresponding to an assumed signal is set in advance, and a signal belonging to the preset frequency band is detected, whereby various signals are detected. Is realized.

  The above is the technology that is the premise of the first embodiment of the present invention. In the presupposed technology, there is a case where it is desired to remotely know from the control console 11 that the analog dedicated line 5 connected to the relay device 15 is not disconnected and the system is operating normally.

  That is, in the relay device 15, as a method of detecting the status of the analog dedicated line 5, for example, the disconnection of the analog dedicated line 5, for example, the control signal and the monitoring signal assigned to the B1 channel and the B2 channel of the 2B + D ISDN line 3 If the signal disconnection detection result of the analog dedicated line 5 is given to the information signal bit used in the control signal and can be notified to the host device 13 and the control console 11, the control console 11 detects the disconnection of the analog dedicated line 5. Can be done.

  However, when the disconnection of the analog dedicated line 5 is detected, the information signal bit of the ISDN line 3 has already been assigned 3 bits for control and monitoring. Therefore, there is no room for allocating line disconnection for three analog dedicated lines 5. For this reason, it is necessary to efficiently use 4 bits of the information signal bits and to transmit the line disconnection information for the 3 lines of the analog dedicated line 5 to the host device 13 via the ISDN line 3. Next, Embodiment 1 of the present invention that realizes such data transmission will be described in order.

<Description of configuration>
FIG. 9 is a diagram for explaining a schematic configuration example of a data format per frame applied when monitoring the state of the analog dedicated line 5 included in the voice transmission / reception system 1 according to the first embodiment of the present invention. . As shown in FIG. 9, one frame includes a synchronization signal, a remote operation signal, and an audio signal. Among these, the remote operation signal is provided with, for example, an information signal bit, and includes a signal that cannot be thinned out and a signal that can be thinned out.

  Therefore, the analog dedicated line 5 can be remotely monitored by replacing the signal that can be thinned with another signal, for example, by giving an analog dedicated line monitoring signal. At this time, if the analog leased line monitoring signal has a low transmission frequency, even if it is replaced with a thinning-out enable signal, the entire system will not be greatly affected.

  In other words, it is only necessary to replace the information signal bit corresponding to the signal that can be thinned out with the analog dedicated line monitoring signal, which has a low transmission frequency.

  Next, the system configuration will be described in order. FIG. 10 is a diagram showing an example of the configuration of the voice transmission / reception system 1 according to Embodiment 1 of the present invention. In FIG. 10, compared with what was mentioned above, the change location was shaded. For example, the control console side voice receiving unit 32, the higher level device side voice receiving unit 42, the relay device side voice transmitting unit 51, the relay device side voice receiving unit 52, the lower level device side voice transmitting unit 61, and the lower level device side voice receiving unit 62. Etc.

  FIG. 11 is a diagram showing a transmission function configuration example of the relay device 15 included in the voice transmission / reception system 1 according to Embodiment 1 of the present invention. As shown in FIG. 11, the relay device-side voice transmission unit 51 has a configuration in which a first OSC 211 and a second OSC 212 are different.

  Specifically, when the CH1 control signal from the control signal distributor 182 is in the ON state, the FDM signal modulator 185 causes the first OSC 211 to output a signal having a frequency of 2980 Hz, for example. The FDM signal modulation unit 185 causes the second OSC 212 to output a signal having a frequency of 2920 Hz, for example, when the control signal of CH1 from the control signal distribution unit 182 is in the OFF state. A signal having a frequency of 2980 Hz and a signal having a frequency of 2920 Hz are added and then output to the analog dedicated line 5_1.

  As a result, a process of transmitting signals indicating the ON state and OFF state of the control signal of CH1 to the subordinate device 17_1 of CH1 via the analog dedicated line 5_1 is executed. If there is a malfunction, the subordinate device 17_1 of CH1 cannot obtain a signal indicating either the ON state or the OFF state of the control signal of CH1.

  Therefore, the CH1 subordinate apparatus 17_1 can detect the disconnection of the analog dedicated line 5_1 of CH1. The subordinate device 17_2 of CH2 and the subordinate device 17_3 of CH3 have the same configuration as that of the subordinate device 17_1 of CH1, and perform the same operation, so the description thereof is omitted here.

  FIG. 12 is a diagram showing an example of a reception function configuration of the relay device 15 included in the voice transmission / reception system 1 according to Embodiment 1 of the present invention. As shown in FIG. 12, the repeater side voice receiving unit 52 is different from the above in that three band pass filters are provided.

  That is, the first BPF 251 is a band-pass filter that passes, for example, a 2980 Hz signal that is output when the monitoring signal is ON from the lower-level device 17_1. The second BPF 252 is a band pass filter that passes, for example, a 2920 Hz signal that is output from the lower level device 17_1 when the monitoring signal is in the OFF state. The third BPF 253 is a band-pass filter that passes a signal of, for example, 3140 Hz that is output when the lower device 17_1 detects the disconnection of the analog dedicated line 5_1.

  The level detection processing unit 261 monitors the signal levels of the ON band (ΔF3) of the monitoring signal that has passed through the first BPF 251 and the OFF band (ΔF2) of the monitoring signal that has passed through the second BPF 252, and the ON time band of the monitoring signal When the signal level in (ΔF3) is higher than the signal level in the OFF time band (ΔF2) of the monitoring signal, an ON signal of the monitoring signal of CH1 is output as a digital signal to the monitoring signal organization unit 241.

  When the signal level in the ON time band (ΔF3) of the monitoring signal is lower than the signal level in the OFF time band (ΔF2) of the monitoring signal, the level detection processing unit 261 sends the digital signal as CH1 to the monitoring signal organizing unit 241. The monitoring signal OFF signal is output.

  The level detection processing unit 261 detects that the signal level in the ON time band (ΔF3) of the monitoring signal and the signal level in the OFF time band (ΔF2) of the monitoring signal are both lower than a preset lower limit value. Therefore, it is determined that the line is disconnected, and a CH1 line-off ON signal is output as a digital signal to the monitoring signal organization unit 241.

  The level detection processing unit 261 monitors the signal level in the line disconnection signal band (ΔF4) that has passed through the third BPF 253, and if the signal level has a signal level that exceeds a certain level, the level detection processing unit 261 is subordinate to the relay device 15. It is determined that the lower device 17_1 has detected the disconnection of the analog dedicated line 5_1 directed to the device 17_1, and an ON signal for CH1 lower device detection circuit disconnection is output as a digital signal to the monitoring signal organization unit 241.

  The supervisory signal organization unit 241 organizes the supervisory signals CH1 to CH3, the line break signals CH1 to CH3, and the lower apparatus detection line break signals CH1 to CH3, and transmits them on the 2B + D ISDN line 3. Information according to the communication frame described later with reference to FIGS. 15 and 16 is assigned to the B1 channel b0 to b3 bits of the communication frame.

  Although details will be described later, the first line disconnection shown in FIG. 15 is given a line disconnection signal from CH1 to CH3. Further, the second line disconnection shown in FIG. 15 is given a lower apparatus detection line disconnection signal from CH1 to CH3. As will be described later, each bit of the first line break and the second line break is transmitted at a ratio of, for example, 18 to 1 with respect to the frame to which the monitor signal is added. Thus, the line disconnection signal has no problem even if it has low intelligibility.

  FIG. 13 is a diagram showing a configuration example of each of the transmission function and the reception function of the lower order device 17 included in the voice transmission / reception system 1 according to the first embodiment of the present invention. As shown in FIG. 13, the FDM signal demodulating unit 281 and the FDM signal modulating unit 283 are different from those described above.

  The CH1 FDM signal demodulation unit 281 includes a first BPF 291, a second BPF 294, a level detection processing unit 292, and an LPF 293.

  The first BPF 291 is a band-pass filter that passes a signal having a frequency of 2980 Hz output from the relay device 15 when the control signal is ON. The second BPF 294 is a band pass filter that passes a signal with a frequency of 2920 Hz output from the relay device 15 when the control signal is OFF.

  The level detection processing unit 292 monitors the respective signal levels such as the ON time band (ΔF3) of the control signal that has passed through the first BPF 291 and the OFF time band (ΔF2) of the control signal that has passed through the second BPF 294. When the signal level in the ON time band (ΔF3) is higher than the signal level in the OFF time band (ΔF2) of the control signal, an ON signal of the CH1 control signal is output as a digital signal to the voice transmitting device 63.

  When the signal level in the ON time band (ΔF3) of the control signal is lower than the signal level in the OFF time band (ΔF2) of the control signal, the level detection processing unit 292 sends the CH1 as a digital signal to the voice transmission device 63. A control signal OFF signal is output. The level detection processing unit 292 is configured such that the signal level in the ON time band (ΔF3) of the control signal and the signal level in the OFF time band (ΔF2) of the control signal both fall below a preset lower limit value. In this case, it is determined that the line is disconnected, and the CH1 line disconnection ON signal is output as a digital signal to the lower apparatus voice receiving unit 62.

  The CH1 FDM signal modulation section 283 includes a first OSC 311, a second OSC 312, a third OSC 313, and an LPF 315. The first OSC 311 outputs a signal having a frequency of 2980 Hz when the CH1 monitoring signal from the audio receiving device 64 is in the ON state. The second OSC 312 outputs a signal having a frequency of 2920 Hz when the CH1 monitoring signal from the audio receiving device 64 is in the OFF state. When the third OSC 313 receives the CH1 line disconnection ON signal, the third OSC 313 outputs the CH1 second line disconnection signal at a frequency of 3140 Hz as the lower apparatus detection line disconnection signal. The output of the first OSC 311, the output of the second OSC 312, and the output of the third OSC 313 are added and then output to the CH 1 analog dedicated line 5_1.

  With such a configuration, the disconnection of the analog dedicated line 5_1 of CH1 can be detected on the relay device 15 side. Further, when the channel disconnection signal of CH1 from the lower apparatus side voice transmission unit 61 is in the ON state, a signal having a frequency of 3140 Hz is output from the third OSC 313 to the analog dedicated channel 5_1 of CH1. With such a configuration, the relay device 15 can determine that a line break has been detected in the lower device 17_1.

  FIG. 14 is a diagram showing an example of a reception function configuration of the higher-level device 13 included in the voice transmission / reception system 1 according to Embodiment 1 of the present invention. As shown in FIG. 14, the CH1 relay device detection line disconnection display unit 331 to the CH3 subordinate device detection line disconnection display unit 343 are different.

  The monitoring signal distribution unit 161 receives information given from the b0 bit of the B1 channel to the b3 bit of the B1 channel of the communication frame transmitted on the ISDN line 3 from the ISDN line receiver unit 165. The b0 bit of the B1 channel to the b3 bit of the B1 channel are information according to the communication frame shown in FIG. 15 to be described later, and are a monitoring signal from CH1 to CH3, a line disconnection signal from CH1 to CH3, and from CH1 to CH3. The lower device detection line disconnection signal is given. The monitoring signal distribution unit 161 decomposes the B0 bit of the B1 channel to the b3 bit of the B1 channel into each and outputs it to the control console 11.

  The control desk side voice receiving unit 32 includes a CH1 relay device detection line disconnection display unit 331, a CH2 relay device detection line disconnection display unit 332, a CH3 relay device detection line disconnection display unit 333, a CH1 subordinate device detection line disconnection display unit 341, and a CH2. A lower apparatus detection line disconnection display unit 342 and a CH3 lower apparatus detection line disconnection display unit 343 are added.

  The CH1 relay device detection line disconnection display unit 331 receives notification of the first line disconnection of CH1 from the host device 13, and notifies the operator that the relay device 15 detects the disconnection of CH1 by a lamp or the like. . Similarly, the CH2 relay device detection line disconnection display unit 332 notifies the operator that the relay device 15 has detected the CH2 line disconnection. Similarly, the CH3 relay apparatus detection line disconnection display unit 333 notifies the operator that the CH3 relay line disconnection is detected by the relay apparatus 15.

  The CH1 lower apparatus detection line disconnection display unit 341 receives a notification of the second line disconnection of CH1 from the upper apparatus 13, and notifies the operator by a lamp or the like that the lower apparatus 17_1 has detected the disconnection of CH1. . Similarly, the CH2 lower apparatus detection line disconnection display unit 342 notifies the operator that the lower apparatus 17_2 has detected the CH2 disconnection. Similarly, the CH3 lower apparatus detection line disconnection display unit 343 notifies the operator that the CH3 line disconnection is detected in the lower apparatus 17_3.

  FIG. 15 is a diagram for explaining a schematic configuration example of a data format applied when monitoring the state of the analog dedicated line 5 included in the voice transmission / reception system 1 according to Embodiment 1 of the present invention, in association with the frame number. It is. FIG. 16 is a diagram illustrating, in time series, a schematic configuration example of a data format applied when monitoring the state of the analog dedicated line 5 included in the voice transmission / reception system 1 according to the first embodiment of the present invention.

  Specifically, in the B1 channel, “A” is given to the b0 bit as a bit corresponding to the F bit as a synchronization signal. The F bit is an ITU-T (International Telecommunication Union Telecommunication Standardization Sector) X. This is a 50-system frame pattern, and this frame pattern enables the receiving side to recognize the frame number. In the above description, an example in which the F bit is used as a synchronization signal has been described. However, the communication frame is particularly limited as long as it can be synchronized between the transmission-side device and the reception-side device in each communication frame. It is not a thing.

  In operation, “A” may be identified as having the presence or absence of an alarm, for example, when there is no alarm when 1 and when there is an alarm when 0. “A” is not particularly limited here as long as it has a meaning corresponding to, for example, the absence of an incoming pulse and a loss of frame alignment.

  In the B1 channel, the b1 bit is provided with a control signal for CH1, a monitoring signal for CH1, and channel disconnection detection information for CH1. However, the control signal and the monitoring signal are given to each of 18 bits in the 20-bit cycle in which the F bit of the synchronization signal circulates. The line disconnection detection information is given to 2 bits in a 20-bit cycle in which the F bit of the synchronization signal circulates. Compared with the monitoring signal, the line disconnection detection information is less frequently given the number of bits. As a result, in the system, the responsiveness of the line disconnection detection information is unnecessary, and therefore, for example, it may be given to each of 2 bits in the 20-bit period.

  For example, FIG. 16 shows a case where the b1 bit in the B1 channel is time-series. As shown in FIG. 16, the synchronization signal b0 bit has “1”, “1”, “0”, “1”, “0”, “0” with the A bit as the start bit as time passes. ”,“ 1 ”,“ 0 ”,“ 0 ”,“ 0 ”,“ 0 ”,“ 1 ”,“ 0 ”,“ 1 ”,“ 0 ”,“ 1 ”,“ 1 ”,“ 1 ”, “0” is given in order. Along with the b0 bit, the b1 bit of CH1 includes “monitor”, “first line disconnection”, “monitor”, “monitor”, “monitor”, “monitor”, “monitor”, “monitor”, “monitor”. ”,“ Monitor ”,“ monitor ”,“ second line disconnection ”,“ monitor ”,“ monitor ”,“ monitor ”,“ monitor ”,“ monitor ”,“ monitor ”,“ monitor ”,“ monitor ” It is given in order. The A bit and “monitor” are the correspondence between the first b0 bit and the b1 bit.

  That is, as shown in FIGS. 15 and 16, the frame number, the synchronization signal, the control signal and the monitoring signal, and the audio signal encoded by ADPCM are associated with each other. Therefore, a corresponding signal is specified from the synchronization signal.

  For example, the host device 13 receives a communication frame via the ISDN line 3 and refers to the b0 bit corresponding to the synchronization signal in the received communication frame, thereby various signals associated with the synchronization signal. B1 bit to b3 bit type corresponding to. For example, as shown in FIG. 16, when it is assumed that information related to “first line disconnection” comes after the synchronization signal A bit, the b0 bit of the synchronization signal specifies the meaning of the b1 bit.

  In the description of FIGS. 15 and 16, an example in which the first line break and the second line break are transmitted by being replaced with the monitoring signal at a constant ratio has been described. However, the present invention is not particularly limited thereto. It is not something. For example, the first line break may be transmitted and the second line break may not be transmitted. Further, for example, the second line disconnection may be transmitted and the first line disconnection may not be transmitted. In other words, any data configuration that can grasp the status of the analog dedicated line 5 by replacing the signal that can be thinned out with a signal that includes the status of the analog dedicated line 5 is acceptable. It is not limited.

  In the B1 channel, the b2 bit is provided with a control signal for CH2, a monitoring signal for CH2, and channel disconnection detection information for CH2. However, the control signal and the monitoring signal are given to each of 18 bits in the 20-bit cycle in which the F bit of the synchronization signal circulates. Further, the line disconnection detection information is given to each of 2 bits in a 20-bit cycle in which the F bit of the synchronization signal circulates.

  In the B1 channel, the b3 bit is assigned a control signal for CH3, a monitoring signal for CH3, and channel disconnection detection information for CH3. However, the control signal and the monitoring signal are given to each of 18 bits in the 20-bit cycle in which the F bit of the synchronization signal circulates. Further, the line disconnection detection information is given to each of 2 bits in a 20-bit cycle in which the F bit of the synchronization signal circulates.

  In the B1 channel, a signal obtained by encoding the CH1 transmission audio signal by ADPCM is added to bits b4 to b7. That is, a signal other than the transmission voice signal as described above, for example, a control signal, a monitoring signal, and line disconnection information can be given to the B1 channel by the amount compressed by encoding using ADPCM. .

  In the B2 channel, a signal obtained by encoding the CH2 transmission audio signal by ADPCM is added to the b0 to b3 bits. In the B2 channel, a CH3 transmission audio signal is added to the b4 to b7 bits.

  Next, frequency bands of various signals will be described. FIG. 17 is a diagram illustrating an example of each frequency band of the control signal and the monitoring signal according to Embodiment 1 of the present invention. FIG. 18 is a diagram illustrating an example of a frequency band corresponding to line disconnection information detected by the lower order device 17 according to Embodiment 1 of the present invention.

  The audio signal band (ΔF1) is assigned a low frequency band, for example, a band of 2700 Hz or less. The ON time band of the control signal and the ON time band (ΔF3) of the monitoring signal are assigned to a frequency band higher than the band (ΔF1) of the audio signal, for example, 2960 Hz to less than 3000 Hz. The control signal OFF time band and the monitoring signal OFF time band (ΔF2) are assigned to a frequency band higher than the audio signal band (ΔF1), for example, 2900 Hz to less than 2940 Hz.

  Further, as shown in FIG. 18, a line disconnection signal band (ΔF4) for notifying that the disconnection of the analog dedicated line 5 from the relay apparatus 15 to the lower apparatus 17 is detected is added. The line disconnection signal band (ΔF4) is assigned to a frequency band higher than the audio signal band (ΔF1), for example, 3100 Hz or more and less than 3200 Hz.

  Thus, since the frequency band corresponding to each signal is uniquely assigned, the audio transmission / reception system 1 can transmit various signals by frequency division multiplexing, and a band-pass filter and a low-pass filter. Necessary signals can be easily extracted by a filter circuit such as a filter.

<Description of effects>
As described above, the voice transmission / reception system 1 detects the disconnection of the analog dedicated line 5 by the relay device 15 and the subordinate device 17 by changing the configuration of the communication frame for data transmission of the ISDN line 3 and the analog dedicated line 5. The detection result can be transmitted to the host device 13 and the control console 11, and the operator using the control console 11 can be notified of the disconnection of the analog dedicated line 5.

  For example, the voice transmission / reception system 1 uses the information signal bit so that the relay device 15 transmits information including the status of the analog dedicated line 5 to the host device 13 via the ISDN line 3. 11 can remotely monitor the status of the analog leased line 5.

  Specifically, since the information corresponding to the monitoring signal can be thinned out of the information signal bits, the voice transmission / reception system 1 detects the disconnection of the analog dedicated line 5 by using the information signal bit corresponding to the monitoring signal. The result is replaced at a constant ratio according to the synchronization signal. As a result, the voice transmission / reception system 1 can transmit the status of the analog dedicated line 5 to the control console 11, so that the control console 11 can remotely monitor the status of the analog dedicated line 5.

  In the above description, the line disconnection has been described as an example of the situation of the analog dedicated line 5. However, the present invention is not particularly limited to this. For example, the control console 11 may monitor the open / closed state of a door at a remote location via the analog dedicated line 5. For example, the control console 11 may monitor the operating state of the air conditioner in a remote place via the analog dedicated line 5. In any case, the voice transmission / reception system 1 can monitor various information by replacing the information signal bits that can be thinned out with signals of other meanings. As a result, information signal bits can be used efficiently and network resources can be used effectively.

  In the above description, the level detection processing unit 261 has preset both the signal level in the ON time band (ΔF3) of the monitoring signal and the signal level in the OFF time band (ΔF2) of the monitoring signal. Although it has been described that it is determined that the line is disconnected when the value falls below the lower limit value, the present invention is not particularly limited to this.

  For example, it is unnecessary to determine the signal level in the ON time band (ΔF3) of the monitoring signal among the signal level in the ON time band (ΔF3) of the monitoring signal and the signal level in the OFF time band (ΔF2) of the monitoring signal. In the implementation mode, the level detection processing unit 261 may determine the line disconnection only based on whether or not the OFF time band (ΔF2) of the monitoring signal is below a preset lower limit value.

  Further, for example, among the signal level in the ON time band (ΔF3) of the monitoring signal and the signal level in the OFF time band (ΔF2) of the monitoring signal, the signal level in the OFF time band (ΔF2) of the monitoring signal is determined. In the case of an unnecessary implementation, the level detection processing unit 261 may determine the line disconnection only based on whether or not the ON time band (ΔF3) of the monitoring signal falls below a preset lower limit value.

  That is, it is important to determine whether the line is disconnected by directly or indirectly using the signal level in the ON time band (ΔF3) of the monitoring signal and the signal level in the OFF time band (ΔF2) of the monitoring signal. In an implementation in which it is not necessary to directly use the monitoring signals in both bands, the level detection processing unit 261 includes the signal level in the ON time band (ΔF3) of the monitoring signal and the OFF time band (ΔF2) of the monitoring signal. The disconnection may be determined based on any of the signal levels.

  In the drawings of the first embodiment, the relationship between the sizes of the constituent members may be different from the actual one. In the drawings of the first embodiment, the same reference numerals are added to the same or corresponding parts, and this is common throughout the entire specification. Furthermore, the form of the component described in the whole specification is merely an example, and is not limited to these descriptions.

  DESCRIPTION OF SYMBOLS 1 Voice transmission / reception system, 3 ISDN line, 5, 5_1, 5_2, 5_3 Analog leased line, 11 Control console, 13 Upper apparatus, 15 Relay apparatus, 17, 17_1, 17_2, 17_3 Lower apparatus, 31 Control console side voice transmission part, 32 Control console side voice reception unit, 41 Upper device side voice transmission unit, 42 Upper device side voice reception unit, 51 Relay device side voice transmission unit, 52 Relay device side voice reception unit, 61, 71, 81 Lower device side voice transmission Unit, 62, 72, 82 Lower device side voice receiving unit, 63, 73, 83 Voice transmitting device, 64, 74, 84 Voice receiving device, 101 CH1 operation unit, 102 CH2 operation unit, 103 CH3 operation unit, 111-113 Audio input unit, 121 Control signal organization unit, 123 Transmission audio signal processing unit, 125 ISDN line driver unit, 131, 133, 35, 171, 173, 202, 175, 204, 206, 271, 273, 275 CODEC, 132, 134, 136, 272, 274, 276 ADPCM converter, 141 CH1 monitoring signal display, 142 CH2 monitoring signal display 143 CH3 monitoring signal display unit 151-153 audio output unit 161 monitoring signal distribution unit 163 received audio signal processing unit 165 ISDN line receiver unit 172 174 176 201 201 203 205 ADPCM demodulating unit 181 ISDN line receiver unit, 182 control signal distribution unit, 183 transmission voice signal processing unit, 185-187 FDM signal modulation unit, 211, 311 first OSC, 212, 312 second OSC, 213 third OSC, 215-217 LPF, 231-233 FDM signal demodulator, 241 Monitoring signal organizing unit, 243 Received audio signal processing unit, 245 ISDN line driver unit, 251, 291 1st BPF, 252, 294 2nd BPF, 253 3rd BPF, 255-257, 293, 315-317 LPF, 261, 292 levels Detection processing unit, 281 FDM signal demodulation unit, 283 FDM signal modulation unit, 313 third OSC, 331 CH1 relay device detection line disconnection display unit, 332 CH2 relay device detection line disconnection display unit, 333 CH3 relay device detection line disconnection display unit, 341 CH1 lower apparatus detection line disconnection display part, 342 CH2 lower apparatus detection line disconnection display part, 343 CH3 lower apparatus detection line disconnection display part.

Claims (21)

Applied to audio transmission / reception system composed of control console, host device, and lower device,
Provided between the upper device and the lower device;
It is connected to the host device via an ISDN line,
The subordinate device is a relay device connected by an analog leased line,
A voice transmission unit on the relay device side;
A voice receiving unit on the relay device side;
With
The relay device side voice transmitter is
A remote operation signal and an audio signal are transmitted to the lower device;
The relay device side voice receiving unit,
The remote control signal and the audio signal are received from the subordinate device,
In the ISDN line, for each frame, data including a synchronization signal, the remote operation signal, and the audio signal is transmitted to the control console via the host device.
Of the signals that cannot be thinned out and the signals that can be thinned out included in the remote operation signal, the signals that can be thinned out are replaced with information including the status of the analog dedicated line, and transmitted according to the synchronization signal. A relay device characterized by The relay device side voice receiving unit,
Organizing the signal that can be thinned out, including a control signal to be transmitted to the lower-level device and a monitoring signal received from the lower-level device,
According to the state of the control signal and the state of the monitoring signal included in the signal that can be thinned, the disconnection state of the analog dedicated line is detected as a first line disconnection,
When the detection result of the disconnection state of the analog dedicated line is received from the lower-level device, it is detected as a second disconnection,
The relay apparatus according to claim 1, wherein information relating to at least one of the first line break and the second line break is transmitted to the control console. The relay device side voice transmitting unit and the relay device side voice receiving unit are:
A first frequency and a second frequency are set;
Corresponding to the first frequency to the ON state of the control signal,
The second frequency corresponds to the OFF state of the control signal,
Making the first frequency correspond to the ON state of the monitoring signal;
The second frequency corresponds to the OFF state of the monitoring signal,
The relay device side voice receiving unit,
When both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than a preset first threshold, it is detected as the first line disconnection. The relay device according to claim 2. The relay device side voice receiving unit,
A third frequency is set,
As a result of determining that the signal level corresponding to the control signal is lower than the first threshold set in advance in the lower level device, the signal level corresponding to the third frequency is received from the lower level device; 4. The relay apparatus according to claim 3, wherein when the signal level corresponding to the third frequency is equal to or higher than a second threshold set in advance, it is detected as the second line disconnection. 5. The relay device side voice transmitting unit and the relay device side voice receiving unit are:
The first frequency, the second frequency, and the third frequency are set to a frequency band larger than the frequency band of the audio signal;
The relay according to claim 4, wherein a state different from the line disconnection state is set in a fourth frequency band larger than the first frequency, the second frequency, and the third frequency. apparatus. The relay device side voice transmitter is
Equipped with an oscillator that oscillates the corresponding signal level for each preset frequency,
The oscillator is
When the control signal is in an ON state, a signal level corresponding to the first frequency is supplied to the lower device,
6. The relay device according to claim 3, wherein when the control signal is in an OFF state, a signal level corresponding to the second frequency is supplied to the lower-level device. The relay device side voice receiving unit,
A level detection processing unit that compares a signal level corresponding to each preset frequency with each of the first threshold and the second threshold;
The level detection processing unit
When both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than the first threshold, it is detected as the first line disconnection,
The relay apparatus according to claim 6, wherein when the signal level corresponding to the third frequency is equal to or higher than the second threshold value, the second line disconnection is detected. Applied to audio transmission / reception system composed of control console, host device, and lower device,
Provided between the upper device and the lower device;
It is connected to the host device via an ISDN line,
The subordinate device is a voice transmission / reception method executed by a relay device connected by an analog leased line,
In the ISDN line, for each frame, data composed of a synchronization signal, a remote operation signal, and a voice signal is transmitted to the control console via the host device.
Transmitting the remote operation signal and the audio signal to the lower-level device;
The remote control signal and the audio signal are received from the subordinate device,
Of the signals that cannot be thinned out and the signals that can be thinned out included in the remote operation signal, the signals that can be thinned out are replaced with information including the status of the analog dedicated line, and transmitted according to the synchronization signal. A voice transmission / reception method characterized by the above. When the lower device detects the disconnection state of the analog dedicated line, the detection result is transmitted to the relay device,
Organizing the signal that can be thinned out, including a control signal to be transmitted to the lower-level device and a monitoring signal received from the lower-level device,
According to the state of the control signal and the state of the monitoring signal included in the signal that can be thinned, the disconnection state of the analog dedicated line is detected as a first line disconnection,
When the detection result of the line disconnection state is received from the lower-level device, it is detected as a second line disconnection,
9. The voice transmitting / receiving method according to claim 8, wherein information relating to at least one of the first line disconnection and the second line disconnection is transmitted to the control console. A first frequency and a second frequency are set;
Corresponding to the first frequency to the ON state of the control signal,
The second frequency corresponds to the OFF state of the control signal,
Making the first frequency correspond to the ON state of the monitoring signal;
The second frequency corresponds to the OFF state of the monitoring signal,
When both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than a preset first threshold, it is detected as the first line disconnection. The voice transmission / reception method according to claim 9. A third frequency is set,
If the signal level corresponding to the control signal is less than the preset first threshold, the signal level corresponding to the third frequency is transmitted to the relay device,
11. The voice transmitting / receiving method according to claim 10, wherein when the signal level corresponding to the third frequency is equal to or higher than a second threshold set in advance, the second line disconnection is detected. The first frequency, the second frequency, and the third frequency are set to a frequency band larger than the frequency band of the audio signal;
The voice according to claim 11, wherein a state different from the line disconnection state is set in a fourth frequency band larger than the first frequency, the second frequency, and the third frequency. Transmission / reception method. When the control signal is in an ON state, a signal level corresponding to the first frequency is supplied to the lower device,
The voice transmission / reception method according to any one of claims 10 to 12, wherein when the control signal is in an OFF state, a signal level corresponding to the second frequency is supplied to the lower-level device. When both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than the first threshold, it is detected as the first line disconnection,
14. The voice transmission / reception method according to claim 13, wherein when the signal level corresponding to the third frequency is equal to or higher than the second threshold, the second line disconnection is detected. Consists of a control console, a host device, a relay device, and a lower device. The host device and the relay device are connected by an ISDN line, and the relay device and the lower device are connected by an analog dedicated line. An audio transmission / reception system,
The relay device is
A remote operation signal and an audio signal are transmitted to the lower device;
The remote control signal and the audio signal are received from the subordinate device,
In the ISDN line, for each frame, data including a synchronization signal, the remote operation signal, and the audio signal is transmitted to the control console via the host device.
Of the signals that cannot be thinned out and the signals that can be thinned out included in the remote operation signal, the signals that can be thinned out are replaced with information including the status of the analog dedicated line, and transmitted according to the synchronization signal. A voice transmission / reception system. The subordinate device is:
When the lower device detects the disconnection state of the analog dedicated line, the detection result is transmitted to the relay device,
The relay device is
Organizing the signal that can be thinned out, including a control signal to be transmitted to the lower-level device and a monitoring signal received from the lower-level device,
According to the state of the control signal and the state of the monitoring signal included in the signal that can be thinned, the disconnection state of the analog dedicated line is detected as a first line disconnection,
When the detection result of the line disconnection state is received from the lower-level device, it is detected as a second line disconnection,
The voice transmission / reception system according to claim 15, wherein information relating to at least one of the first line disconnection and the second line disconnection is transmitted to the control console. The relay device is
A first frequency and a second frequency are set;
Corresponding to the first frequency to the ON state of the control signal,
The second frequency corresponds to the OFF state of the control signal,
Making the first frequency correspond to the ON state of the monitoring signal;
The second frequency corresponds to the OFF state of the monitoring signal,
When both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than a preset first threshold, it is detected as the first line disconnection. The voice transmission / reception system according to claim 16. The subordinate device and the relay device are:
A third frequency is set,
The subordinate device is:
If the signal level corresponding to the control signal is less than the preset first threshold, the signal level corresponding to the third frequency is transmitted to the relay device,
The relay device is
18. The voice transmission / reception system according to claim 17, wherein when the signal level corresponding to the third frequency is equal to or higher than a second threshold set in advance, the second line disconnection is detected. The subordinate device and the relay device are:
The first frequency, the second frequency, and the third frequency are set to a frequency band larger than the frequency band of the audio signal;
The voice according to claim 18, wherein a state different from the line disconnection state is set in a fourth frequency band larger than the first frequency, the second frequency, and the third frequency. Transmission / reception system. The relay device is
Equipped with an oscillator that oscillates the corresponding signal level for each preset frequency,
The oscillator is
When the control signal is in an ON state, a signal level corresponding to the first frequency is supplied to the lower device,
The audio transmission / reception system according to any one of claims 17 to 19, wherein when the control signal is in an OFF state, a signal level corresponding to the second frequency is supplied to the lower-level device. The relay device is
A level detection processing unit that compares a signal level corresponding to each preset frequency with each of the first threshold and the second threshold;
The level detection processing unit
When both the signal level corresponding to the first frequency and the signal level corresponding to the second frequency are less than the first threshold, it is detected as the first line disconnection,
21. The voice transmission / reception system according to claim 20, wherein when the signal level corresponding to the third frequency is equal to or higher than the second threshold, the second line disconnection is detected.

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