JP2605889B2 - Closed area wired communication device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed-area wired communication device using an unused channel in a video-based wired communication system constituted by a coaxial line such as a CATV or a common listening network. About.

2. Description of the Related Art Conventionally, this type of wired communication system is configured of one center device and a plurality of terminal devices, and broadcast, that is, unidirectional communication from the center device to a plurality of terminal devices, Communication is performed between terminal devices via the exchange function of the center device. One communication line is allocated to each terminal device, and when each terminal device performs mutual communication, the center device is requested to connect a communication line with the corresponding terminal device, and communication is performed after the line is established. .

In addition, during communication between the terminals, the communication line is blocked, so that the center device cannot broadcast to each terminal device. Therefore, in such a case, the center device superimposes a broadcast reception command signal of a frequency outside the voice band on the modulation signal so that the center device can request each terminal device for broadcast reception. A device having an interrupt function for notifying has been developed.

However, in the above-described conventional closed-area wired communication device, when a broadcast reception command signal is sent from the center device, all terminals must receive the broadcast reception command signal. However, there is a problem that even when the communication is performed, it is necessary to temporarily suspend the communication and receive a broadcast from the center.

The present invention solves the above-described problem. When performing communication between terminal devices, even if an interrupt request for broadcast reception is received from the center device, a broadcast request from the center is transmitted from the center device to the terminal device. It is an object of the present invention to provide a closed wired communication device that allows the user to select whether to receive the communication immediately or after the communication between the terminals is completed.

Means for Solving the Problems In order to achieve the above object, the present invention provides a method of transmitting a broadcast reception command signal of a frequency outside the voice band from a center device to each terminal when performing communication between terminal devices. When there is an interrupt request that is superimposed on the modulation signal and notified, whether an interrupt is received from the center or immediately after completion of inter-terminal communication by inputting a predetermined external designation signal in each terminal Is provided.

Therefore, according to the present invention, when an interruption request for broadcast reception is received from the center device during communication between terminal devices, the importance of the communication in each terminal device performing mutual communication is determined. Has the effect that it is possible to select whether to receive or not to receive the broadcast in accordance with.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention.
In FIG. 1, reference numeral 11 denotes a center device, 12 denotes a transmission medium composed of a coaxial line or the like, and 13, 14, 15, and 16 denote terminal devices.
The number of terminal devices can be set arbitrarily.

FIG. 2 shows the configuration of the center device 11, in which 21 is a splitter, 22 is a separator, 23 is a mixer, 24 is a mixed signal generator,
25 is a tone generator, 26 is a starter, and 27 is a coupler.

FIG. 3 shows the configuration of the terminal devices 13 to 16, 31 is a branching device, 32 is a microprocessor, 33 is a synthesizer for reception, 34 is a tone detector, 35 is a synthesizer for transmission, 36 is an audio output, 37 Is an audio input, 38 is an external designation signal input port, and 39 is an external signal generator.

Next, the operation of the above embodiment will be described. In FIG. 1, when the terminal devices 13 and 14 communicate with each other, the terminal device 13 first contacts the center device 11 via the communication line of the transmission medium 12, and requests the allocation of the communication line. In response to this, the center device 11 allocates a communication line between the terminal devices 13 and 14. Accordingly, the terminal device 13 performs communication using the communication line instructed to the terminal device 14.

The details of this communication will be described with reference to FIG. 2 and FIG. First, the terminal device 13 that has received the voice input 37
After modulating 37 with the reference frequency of the synthesizer for transmission 35, it is transmitted to the transmission medium 12 via the splitter 31. Signal taken from the transmission medium 12 into the branching device 21 of the center device 11
In the signal 211, the communication uplink signal 212 is extracted from the signal by the separator 22. The mixer 23 combines the extracted upstream signal 212 with the mixed signal 215 generated by the mixed signal generator 24 to form a downstream signal 216. The coupler 27 sends the downstream signal 216 to the transmission medium 12.

The downlink signal sent to the terminal device 14 through the transmission medium 12 is divided into a transmission signal and a reception signal by the splitter 31.
The received signal is sent from the splitter 31 to the receiving synthesizer 33, and is combined and sent to the microprocessor 32,
It is analyzed here. The microprocessor 32 instructs the reception synthesizer 33 on the reception channel and the transmission synthesizer 35 on the transmission channel. The receiving synthesizer 33 performs communication by converting it into an audio output 36 by an audio processor or the like using the designated channel.

When the center device 11 broadcasts to each terminal device in an emergency or the like, the center device 11 sends an activation signal 213 from an activation device 26 constituted by a microprocessor or the like.
To cause the tone generator 25 to generate a tone signal 214 which is a broadcast reception command signal of a frequency outside the voice band. The tone signal 214 is superimposed on the mixed signal 215 from the mixed signal generator 24, is put on the down signal 216 from the mixer 23, and is sent from the combiner 27 to the transmission medium 12.

A signal including a tone signal transmitted from the transmission medium 12 to each terminal device is detected by a tone detector 34 in each terminal device. When the tone signal is detected, the microprocessor 32 selects another reception channel designated for communication between the terminal devices to receive an instruction from the center device 11, and selects a different channel.
And the receiving synthesizer 33 receives the signal of that channel. The center apparatus 11 thereafter performs broadcast communication using the designated communication line.

On the other hand, when the terminal devices 13 and 14 are communicating with each other when the broadcast reception command signal is sent from the center device 11, for example, it is more important that the terminal devices 13 communicate with each other. If determined, the terminal device 13 is connected to the external signal generator.
39 For example, after connecting the telephone via a modular jack etc., operate the telephone switch during a call to
Operate the button to generate the DTMF signal. Next, the external designation signal input port 38 detects this DTMF signal and sends it to the microprocessor 32. When detecting the input of the DTMF signal, the microprocessor 32 suspends the switching of the line for receiving the broadcast from the center device described above, and converts the DTMF signal through the line between the currently communicating terminal devices 14. Send to terminal device 14. Upon receiving this, the microprocessor 32 detects the DTMF signal, similarly suspends the line switching for receiving the broadcast from the center device, and continues the communication with the terminal device 13.

In the above case, the terminal device 13 communicates with the currently communicating terminal device.
If it is determined that the communication with 14 is not so important, by not operating the external signal generator 39,
Under the control of the microprocessor 32, a broadcast reception request from the center device can be accepted.

As described above, according to the above-described embodiment, even when a broadcast reception request is issued from the center device while the terminal devices are communicating with each other, simply operating the telephone or another external signal generator is sufficient. This has the effect that communication between terminals can be continued as it is.

Advantageous Effects of the Invention As is clear from the above embodiments, the present invention is applicable to the case where mutual communication is performed when an interruption request for broadcast reception is received from the center device during communication between terminal devices. There is an advantage that the terminal device can select whether to receive the broadcast communication or to continue the mutual communication between the terminal devices according to the importance of the communication.

Further, there is an effect that the above-described device can be realized at low cost without significantly increasing equipment costs, material costs, and the like, and without deteriorating line quality.

[Brief description of the drawings]

1 is a system configuration diagram of a closed-area wired communication device according to one embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a center device according to one embodiment of the present invention, and FIG. 3 is a terminal according to one embodiment of the present invention. It is a schematic structure figure of an apparatus. 11 ... Center device, 12 ... Transmission medium, 13, 14, 15, 16
...... Terminal device, 21 ... Branch device, 22 ... Separator, 23 ... Mixer, 24 ... Mixed signal generator, 25 ... Tone generator, 26 ... Activator, 27 ... Coupler, 211 …… Transmission medium 1
Signal flowing through 2, 212 ... Communication upstream signal, 213 ...
Emergency start signal, 214: Broadcast reception command signal (tone signal) outside the voice band to be superimposed, 215: Mixed signal for converting upstream band signal to downstream band signal, 216: mixed downstream Signal, 31 ... branching device, 32 ... microprocessor, 33 ... receiving synthesizer, 34 ... tone detector, 35 ... transmitting synthesizer, 36 ... sound output,
37 ... voice input, 38 ... external designated signal input, 39 ... external signal generator.

Claims (1)

(57) [Claims] 1. A communication device main body in which a center device and a plurality of terminal devices are connected by wire, and a broadcast reception command signal of a frequency outside a voice band for each terminal is superimposed on a modulation signal for each terminal. Broadcast receiving command means for notifying and transmitting, line selection switching means housed in the terminal device and selectively switching connection with the center device and connection between terminal devices, and When receiving a broadcast reception command from the center device while performing communication between devices, when interrupting communication between terminal devices,
When the connection to the center device is switched by the line selection switching means and communication between terminal devices is continued, DT
Switching control means for outputting the hold signal of the MF to the terminal device of the other party, housed in the terminal device of the other party, and inputting the hold signal, even if receiving a broadcast reception command from the center device, A closed-area wired communication device comprising: communication control means for continuing current communication.