JPH071882Y2 - Data communication / voice communication switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention is a data communication / voice system in which data communication and voice communication are performed using the same transmission line, and interruption of voice communication can be performed during data communication. The present invention relates to a communication switching device.

BACKGROUND ART In recent years, data communication and voice communication are performed using the same transmission path, and voice communication may be interrupted during data communication. In this way, if voice communication is interrupted in the middle of data communication, the transmission signal between the data transmitting / receiving means performing the data communication is interrupted, and the operating states of the other data transmitting / receiving means cannot be discriminated from each other.
For this reason, as a method of returning data communication after interruption of voice communication, a method of temporarily disconnecting the line and performing voice communication and then performing data communication from the initial state again, and a preset time of voice communication are set. A method of automatically returning to data communication after a predetermined time from the start of voice communication is considered. However, the former method can be used only for transmission lines that can detect line disconnections, such as telephone-type public communication lines (so-called subscriber telephone lines) and private lines. It cannot be used on a transmission line that cannot be distinguished from the state. Also, disconnect the connected line once,
To return both to the initial state and perform data communication again,
There is also the problem of inefficiency in terms of time and line occupancy. The latter method can be used on any transmission line, but since voice communication is not constant in time,
If the set time is shorter than the call time, the conversation will be interrupted midway, and if the set time is longer than the call time, use time will be wasted. Further, if one of the power failures occurs in the middle of voice communication, the other one cannot detect the state and data communication is disabled, resulting in inconvenience.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to transmit a call signal between both devices during voice communication so that voice communication can be performed during voice communication. It is an object of the present invention to provide a data communication / voice communication switching device that enables both devices to recognize a certain thing and can perform voice communication at any time on any transmission path.

[Disclosure of the Invention] (Example) In this example, an example of using an NTT telephone public communication line as a transmission line is shown.

As shown in FIG. 1, the data transmission / reception means includes a computer device 11 that serves as a data transmission / reception terminal, and a computer device 11.
And a modem 12 for performing signal conversion between the input / output signal and the signal on the transmission line 1. The modem 12 is connected to the transmission line 1 via the converter 3 and the line connection device 2. The computer device 11 is provided with a microprocessor, and the modem 12 is compatible with at least one of the half-duplex system and the full-duplex system.
The converter 3 is inserted between the modem 12 and the line connection device 2, and switches between data communication and voice communication by a control signal from the computer device 11.
That is, the computer device 11 also operates as control means. As the line connection device 2, for example, as shown in FIG. 2, a network control device 5 for selecting a connection partner, a line transformer 6, and a protection line for converting the 2-wire transmission line 1 into 4-wire in-device wiring. It is composed of a 2-line / 4-line converter 7 including a sound circuit and the like. If a network control device 5 having an automatic dial function is used, a line can be connected by a control signal from the computer device 11.

The voice transmitting / receiving means includes a transmitter 21 and a receiver 28, and the output of the transmitter 21 is added via a band elimination filter 22 to a summing amplifier 24.
Entered in. In the summing amplifier 24, the output of the band elimination filter 22 (Fig. 4 (b)) and the output of the speech signal generating circuit 23 (Fig. 4 (a)) are added. As the call signal generation circuit 23, an oscillation circuit that outputs a single frequency within a frequency band that can be transmitted through the transmission line 1 is used. As shown in FIG. 3A, the band elimination filter 22 has an attenuation band set so as to remove the frequency component corresponding to the output frequency fa of the call signal generation circuit 23 from the output of the transmitter 21. Therefore, the output of the summing amplifier 24 is, as shown in FIG. 4 (c), the voice signal in which the attenuation band set by the band elimination filter 22 is missing and the speech signal set at the specific frequency fa within the attenuation band. Becomes a superimposed signal, and this signal is transmitted through the converter 3 to the transmission signal end TX of the line connection device 2.
Entered in. On the other hand, the output (FIG. 4 (d)) from the reception signal terminal RX of the line connection device 2 is input to the bandpass filter 25 and the bandstop filter 26 via the converter 3. As shown in FIG. 3 (c), the band filter 25 has a pass band set so as to pass the output frequency fb of the call signal generating circuit 23 in the partner station (called station) connected via the transmission path 1. Has been done. Here, the output frequencies of the call signal generating circuit 23 are set to different frequencies which are relatively close to each other between the calling station and the called station. Therefore, as shown in FIG. 4 (e),
A frequency component corresponding to the output frequency fb of the call signal generating circuit 23 of the partner station passes through the bandpass filter 25. The output of the band-pass filter 25 is input to the call detection circuit 27, and the call detection circuit 27 outputs a call detection signal when the signal of the frequency corresponding to the output frequency of the call signal generation circuit 23 in the partner station is equal to or higher than a predetermined level. Output. Call detection circuit
The output of 27 is input to the computer device 11,
While the call detection signal is being input to the computer device 11, the computer device 11 keeps the converter 3 set in the voice transmitting / receiving means side. As shown in FIG. 3 (b), the band elimination filter 26 has an attenuation band set so as to remove the output frequency fb of the call signal generating circuit 23 in the partner station, and therefore FIG. 4 (f).
As shown in, the audio signal in which the frequency component in the attenuation band is missing is output. The output of the band elimination filter 26 is input to the handset 28. Here, the band elimination filter 2
The bandwidths of the band filters 2, 26 and the band filter 25 may be set so as to correspond to the call signal generating circuit 23 of either the calling station or the called station, but in the present embodiment, the filters 22 are used. Bandwidths of 25, 26 are set so as to correspond to the output frequencies fa, fb of both speech signal generating circuits 23, respectively.
Therefore, reflection occurs due to the impedance mismatch of the 2-wire / 4-wire converter, and the output of the summing amplifier 24 is a bandpass filter.
The output of the call signal generation circuit 23 is attenuated by the band stop filter 26 even if it goes around to the band stop filter 25 and the band stop filter 26, so that the call signal is prevented from being input to the handset 28.

A call start / end detection device 4 such as a hook switch is connected to the computer device 11. For example, when the handset is picked up and the call start is detected in an off-hook state, the computer device 11 outputs call request data.
When the handset is placed and the end of the call is detected in the on-hook state, the computer device 11 switches the converter 3 to the data communication side.

In the above example, the call signal generating circuit 23 outputs a single frequency, but a modulated signal obtained by modulating a carrier may be used as the call signal.

(Operation) The operation will be described below. During data communication, the converter 3 is connected to the modem 12 side,
The data output from the computer device 11 is sent to the transmission line 1 via the line connection device 2. Here, if an off-hook state is set to start a call (the transmission line 1 is closed by data communication before off-hook), the calling station requests a call based on the output of the call start / end detection device 4. Data is output from the computer device 11, and the call request data is transmitted to the called station via the transmission line 1. Upon receiving the call request data, the called station switches the converter 3 to the voice communication side by the computer device 11 and returns the call acceptance data. When the caller receives the call acceptance data, the computer device 11 causes the converter 3 to switch the converter 3 to the voice communication side. Switch to the voice communication side. As a result, voice communication becomes possible for both parties, and a signal in which a voice signal and a call signal are superimposed is transmitted between both parties. Here, the voice signal lacks a component of the frequency band including the call signal, but if this bandwidth is set to a predetermined width or less, it does not hinder normal conversation. In this way, since the call signal is transmitted as long as the off-hook state continues, even if the conversation is interrupted in the middle, the signal does not become a non-signal state, and the converter 3 keeps the voice communication side while the call signal is transmitted by both sides. The result is that the conversation can continue for the desired amount of time. Further, when the conversation is ended and put into the on-hook state, the converter 3 is switched to the data communication side at the station that is on-hook, and the call detection signal is not output from the call detection circuit 27 at the partner station. The converter 3 is switched to the data communication side, and the data communication is restarted. As described above, the voice communication can be performed for the required time by interrupting the data communication.

[Advantage of the Invention] As described above, the present invention, when switching from data communication to voice communication, the station that receives each data by exchanging call request data and call acceptance data switches the converter to the voice communication side, During the voice communication, the call signal is continuously transmitted together with the voice signal between both devices, so that both devices can recognize that the voice communication is in progress, and as a result, it is possible to obtain the desired time for any transmission path. The advantage is that voice communication can be performed. That is, in the present invention, by adopting the above-mentioned configuration, the output of the transmitter and the call signal are transmitted to the transmission line in a frequency-multiplexed state during the voice communication, so that the call signal is transmitted during the voice communication. Always transmitted. Therefore, when the voice signal transmission is terminated at one station and the converter is switched to the data transmission / reception side by the call termination detection means, the call detection circuit at the other station does not detect the call signal and the data is automatically transmitted. It will be switched to the transmitting / receiving means side. In short, it is possible to select between data communication and voice communication at any time, and the switching from voice to data and data to voice can be switched at any time according to the user's need. Can be selected with, and when one station switches between voice and data, the other station automatically determines and follows so that it can be used very conveniently. is there. Also, when not used for voice communication, it can be used for data communication, and voice communication can be performed only when necessary, so the transmission line utilization efficiency is high, and the number of lines used can be reduced especially in the case of a fixed-rate leased line, As a result, there is an advantage that the utilization cost can be reduced. Further, if a trouble such as a power failure occurs during voice communication, the other device can recognize the trouble by the call signal, which is advantageous in that the occurrence of the trouble can be easily dealt with.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram embodying a line connection device in the same as above, FIG. 3 is an operation explanatory diagram of each filter used in the same as above, and FIG. FIG. 3 is an operation explanatory diagram showing signals of respective parts indicated by corresponding symbols in FIG. 2. 1 is a transmission line, 2 is a line connection device, 3 is a converter, 4 is a call start / end detection device, 11 is a computer device, 12 is a modem, 21 is a transmitter, 22 is a band elimination filter, and 23 is a call signal generation. A circuit, 24 is a summing amplifier, 25 is a bandpass filter, 26 is a bandstop filter, 27 is a call detection circuit, and 28 is a handset.

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Claims (3)

[Scope of utility model registration request] 1. A data transmission / reception means for performing data communication, and a voice transmission / reception means provided with a transmitter and a receiver for performing voice communication,
A converter that selectively connects one of the data transmission / reception means and the voice transmission / reception means to a transmission line, a control means for switching the conversion means, and a call request from the data transmission / reception means when a voice communication start point is detected during data communication. The data transmission / reception means is provided with a call start detection means for transmitting data, and a call termination detection means for switching the converter to the data transmission / reception means side by the control means when the end point of the voice communication is detected during voice communication. When the data is received, the control means switches the converter to the voice transmission / reception means side and the call reception data is returned, and when the call reception data is received, the control means switches the converter to the voice transmission / reception means side. The means continuously outputs a call signal within a predetermined frequency bandwidth during the period from the start of voice communication to the end of voice communication. A speech signal generation circuit, a first band elimination filter for removing a frequency component corresponding to a speech signal in the output of the transmitter, and a transmission signal by summing the speech signal and the output of the first band elimination filter. And a call detection circuit that detects a call signal of the other station included in the received signal, and a second band that removes the frequency component corresponding to the call signal of the other station in the received signal and outputs it to the handset The converter is set to the voice transmitting / receiving means side by the control means while the call detecting circuit detects the call signal, and the converter means the data transmitting / receiving means side by the control means when the call signal is not detected. A data communication / voice communication switching device which is set to. 2. A utility model registration claim in which a call signal output from the call signal generating circuit is a signal having a single frequency, and the calling station and the called station are set to different frequencies from each other. The data communication / voice communication switching device according to item 1. 3. The data communication / voice communication switching device according to claim 1, wherein the call signal output from the call signal generating circuit is a modulated signal.