JPH06104906A - Closed zone wired communication system - Google Patents

Abstract

PURPOSE:To obtain the closed zone wired communication system with a high transmission efficiency and excellent economy. CONSTITUTION:The communication system is an in-closed area communication system in which information is communicated among plural terminal equipments 12,13,14 connected to a transmission medium through which data are sent and supervisory information is communicated between a supervisory terminal equipment 15 connected to the transmission medium 11 and each of the plural terminal equipments 12,13,14. Then a unit block of data to be sent is subject to time division multiplex into plural time slots, the information is communicated by using one time slot and the supervisory information is communicated by the other time slot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to time division multiplexing of communication signals in a digital cable communication system, and in particular,
The present invention relates to a closed-area wired communication system that realizes a broadcast function and individual communication in the same time slot.

[0002]

2. Description of the Related Art There are several methods for simultaneously using one transmission medium by a plurality of terminals. FDM (frequency division multiplexing) and TDM (time division division) are typical ones.
There is. FDM is a technique used in television broadcasting and the like, in which frequency intervals that do not affect each other are provided and different frequencies are used, and TDM is a signal that is multiple times faster than the speed at which it is actually used. , A method of creating a series of signal configurations (time slots) in which a plurality of terminals output signals that are speeded up in a predetermined order according to a predetermined contract by providing a time gap that does not affect each other in a transmission path. . In TDM, a time slot is repeatedly transmitted from a transmitting side and continuously transmitted, and necessary information is extracted at a receiving side and reduced to a speed at which the information is actually used.

In a communication system using TDM, a transmitting side terminal outputs information in a time slot designated by a center, and a receiving side terminal collects necessary information from a predetermined time slot. In a telephone-type system, direct communication is performed via a pair line during two-way communication in a star network configuration, but in a multi-drop type network, communication is performed between terminals using two time slots in the TDM method. .

At the same time, when configuring a star network in a telephone system, the same information is output to each line, but in a multi-drop network, one terminal is assigned to a predetermined time slot. With respect to the transmitted information, a plurality of terminals collect the information of the time slot.

On the other hand, in recent years, closed area wired communication systems for the purpose of communication within the area have been developed in various places. In such a closed area wired communication system, equipment monitoring, sensor data collection, etc. are realized at a data transmission rate of about 1200 BPS as remote monitoring in the closed area, and remote control such as mutual communication by voice signal in the telephone or emergency stop is realized. Is being carried out.

Therefore, unless forced communication is stopped and each terminal is set to a standby state, information transmission and control for all terminals cannot be realized during a telephone call or during remote monitoring. When this forced communication stop function is executed, the system such as remote monitoring needs to be equipped with a restart function for interruption. For this reason, the personal computer communication system, which has been applied to the conventional closed-area communication system as the closed-area communication system, has been modified with the communication function software.

A conventional closed area wired communication system will be described below. FIG. 5 shows a system configuration of a conventional closed area wired communication system. The configuration of FIG. 5 is, for example, a system which is used for monitoring a gas leak as well as performing a call and data transmission through a closed communication line. In FIG. 5, 11
Is a transmission medium for transmitting voice and data. Reference numeral 12 denotes a terminal device (in this case, a terminal device on the transmission side, which will be referred to as a “transmission terminal” hereinafter). 13 is a terminal device (in this case,
The receiving terminal is referred to as a “receiving terminal” hereinafter). 5
Reference numeral 1 is a communication terminal for monitoring, and in this case, it is a gas leakage sensor device that monitors the state of gas leakage periodically or as necessary and transmits the monitoring data. Reference numeral 52 is also a communication terminal for monitoring, and is a workstation (WS) that collects monitoring data from the gas leak sensor device 51.
Is. In this case, the reception terminal 13 and the gas leak sensor device 51 are the same terminal A when viewed from the transmission medium 11, and are connected to the transmission medium 11 by the common connection line B.

Reference numeral 53 is a center device unit for monitoring the terminals accommodated in the transmission medium, and 54 is a forced communication interruption device for generating an interruption signal. The number of terminals that are other terminals and that are accommodated in the transmission medium 11 is plural.

FIG. 6 shows the internal structure of the receiving terminal 13,
1 is a time division multiplexing unit, 42 is a control unit constituted by a microprocessor, 43 is a buffer, and 44 is a time division multiplexing unit 41.
It is a communication device that receives the signal extracted in step 1 or outputs the compressed information to be sent to the time division multiplexer 41.

The operation of the closed wired communication system configured as described above will be described below. First, when a communication path is established between the transmitting terminal 12 and the receiving terminal 13, the signal transmitted by the transmitting terminal 12 is transmitted by the transmission medium 11
Is transmitted to the receiving terminal 13 via. In this case, when the workstation 52 collects the monitoring data of the gas leak sensor 51, the workstation 52 notifies the center 53 to that effect. In response to this, the center 51 sends the interruption signal generated by the forced communication interruption device 54 onto the transmission medium 11, and the forced interruption detection function 61 in the receiving terminal 13 detects this interruption signal and the transmitting terminal 12 Sharing the transmission medium 11 by disconnecting the communication line between the receiving terminal 13 and the receiving terminal 13 and then newly establishing a communication line between the workstation 52 and the gas leak sensor device 51 to collect information. I was able to.

[0011]

However, the above-mentioned conventional closed-area wired system requires a means having a forced line disconnection function for each terminal, which causes a problem of increasing the cost of the terminal. In addition, even if communication is interrupted at any time during mutual communication, it takes time and effort to devise a communication procedure so that the terminal can operate without trouble after the interruption factor is resolved.
There is a problem that the transmission efficiency is also reduced. Further, it is necessary to modify the software of the communication function in the personal computer communication system which is applied to the closed area communication system in the conventional telephone system, which causes a problem of being uneconomical.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a closed wired communication system with high transmission efficiency and excellent economical efficiency.

[0013]

Information is communicated between a transmission medium for transmitting data and a plurality of terminals accommodated in the transmission medium, and a monitoring terminal accommodated in the transmission medium and the plurality of terminals. A communication method within a closed area for communicating monitoring information with each terminal, time division multiplexing a unit block of data to be transmitted into a plurality of time slots, and communicating the information using one time slot, etc. In the configuration, the monitoring information is communicated using one time slot.

[0014]

With this configuration, when the terminals use the time slots for communication and are communicating with each other, the information can be collected without interruption of the communication by using the monitoring time slots.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the system configuration of an embodiment of the present invention. In FIG. 1, 11 is a transmission medium, 12 is a terminal (in this case, it is a transmission side terminal, and is hereinafter referred to as “transmission terminal”), 13 is also a terminal (in this case, is a reception side terminal, and is hereinafter referred to as “reception terminal”). That is). Reference numeral 14 is a center device for monitoring each terminal accommodated in the transmission medium 11.
Reference numeral 5 denotes a terminal device that monitors devices and broadcasts simultaneously to all terminals, and is, for example, a workstation in a gas leak monitoring system.

FIG. 2 shows a format of a signal transmitted / received among the terminals 12, 13, 14 and the center 15, and particularly shows an example of a time slot configuration. In FIG. 2, 31 indicates a series of continuous signals, and 32 is a unit block of the series of signals. This unit block 32 is composed of address information and two time slots, and the combination is fixed but its contents change.

In each unit block, 33 is address information for identifying a receiver, 34 is a time slot 1 for communication between terminals, and 35 is a time slot 2 for monitoring information.
Is.

FIG. 3 is a sequence diagram showing the communication procedure (protocol) of the present invention. In this communication procedure, time slot 1 and time slot 2 are used for communication.

In FIG. 3, reference numeral 21 indicates a time slot 1.
Is a signal transmitted from the terminal 12 to the center 14 using the, and is a communication request signal for requesting communication with the terminal 13. 22 also uses center slot 1 using time slot 1.
4 is a signal transmitted to the terminal 12, and is a request permission signal for permitting communication between the terminal 12 and the terminal 13. 23
From the center 14 to the terminal 12 using the time slot 1.
And 13 are communication signals that are instructions to use the time slot 2 for mutual communication. Reference numeral 24 indicates mutual communication between the terminal 12 and the terminal 13 using the time slot 2. Reference numeral 25 denotes a signal transmitted from the terminal 15 to the terminal 13 using the time slot 1, which is a broadcast of data or the like to the terminal 13 or a collection of monitoring information.

Therefore, when the line of the mutual communication 24 using the time slot 2 is established, the monitoring communication 25 is realized by using the vacant time slot 1.

FIG. 4 is a block diagram showing the internal structure of the terminals 12 and 13. In FIG. 4, 11 is a transmission medium, 41 is a time division multiplexing unit for generating or extracting time slots, 42 is a control unit composed of a microprocessor,
Reference numeral 43 is a buffer, and 44 is a communication device that receives the signal extracted by the time division multiplexing unit 41 or outputs the compression information to be transmitted to the time division multiplexing unit 41. Reference numeral 45 is a buffer, and 46 is a monitoring device including a gas leak sensor device and the like.

The operation procedure of the closed wired communication system configured as described above will be described with reference to FIGS. 1, 3, 3 and 4. First, when the terminal 12 communicates with the terminal 13, (1) the terminal 12 asks the center 14 for permission to communicate with the terminal 13, receives the designation of the time slot 1 for communication, and receives the designated time. Information is sent to the terminal 1 using the slot 1.
3 is transmitted.

(2) When the terminal 13 is instructed to receive by the address information received prior to the time slot, the information of the time slot 1 instructed by the address information is extracted,
A communication path for mutual communication between the terminal 12 and the terminal 13 is established.

(3) In the terminal 13, the time division multiplexing unit 41 receives the signal 33, and the control unit composed of a microprocessor or the like analyzes the information.

(4) The received signal of the time slot 1 is shaped in timing, speed, etc. by the buffer circuit 43 and supplied to the communication device 44.

(5) When the terminal 15 collects broadcast information to all terminals and device information, it obtains permission from the center 14 and outputs the information to the designated time slot 2.

(6) The center 14 turns on the data reception instruction flag to be transmitted to all terminals and transmits data.

(7) In the terminal 13, the time division multiplexing unit 41 receives the address information 33 designated by the center, and the control unit 42 decodes it.

(8) The buffer circuit 45 receives the information of the time slot 2 supplied by the time division multiplexer 41.

(9) The buffer circuit 45 shapes this signal and supplies the information to the monitoring device 46.

While making the circuit common, the data communication such as the monitoring information can be realized even during the communication between the terminals.

In the description, the directional communication has been described for the sake of convenience, but bidirectional communication can be performed from the terminal 13 to the terminal 12 at the same time using the same time slot, and the time slot configuration may be unexpected.

The characteristics of the closed area wired communication system according to this embodiment and the characteristics of the conventional closed area wired communication system are shown in comparison with each other (Table 1).

[0035]

[Table 1]

As is clear from (Table 1), the closed area wired communication system according to the present embodiment is more economical and the line utilization efficiency is higher than the conventional system.

[0037]

As described above, according to the present invention, it is possible to realize simultaneous instruction and monitoring of devices without interruption of communication during communication between terminals, and also to simplify the system, and Since the configuration can be simplified, it is economical, and since the number of lines used can be reduced, the line utilization efficiency is improved and an excellent closed-area wired communication system can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a closed digital cable communication system according to an embodiment of the present invention.

FIG. 2 is an example of a transmission code of the present invention.

FIG. 3 is a communication procedure (protocol signal configuration diagram) in the present embodiment.

FIG. 4 is a configuration of a terminal according to an embodiment of the present invention.

FIG. 5 is a block diagram of a conventional closed wired communication system.

FIG. 6 is a configuration of a terminal of a conventional closed wired communication system.

[Explanation of symbols]

 11 transmission medium 12 terminal (transmission side) 13 terminal (reception side) 14 center device 15 terminal (for monitoring system) 21 line request signal 22 line request permission signal 23 communication instruction signal 24 intercommunication between terminals 25 monitoring system and terminal Communication 31 Signal from center device to terminal 32 Timeslots of 33 categories Address information 34 Timeslot 1 35 Timeslot 2 41 Time division multiplexing unit 42 Control unit composed of microprocessor etc. 43 Buffer 44 Communication unit 45 Buffer 46 Monitoring device 51 communication terminal 52 communication terminal 53 center device 54 forced communication interruption device 61 forced interruption detection function

Claims (1)

[Claims] 1. A transmission medium for transmitting data, and information communication between a plurality of terminals accommodated in the transmission medium, and a monitoring terminal accommodated in the transmission medium and each of the plurality of terminals. It is a communication method within a closed area for communicating monitoring information, in which a unit block of data to be transmitted is time-division multiplexed into a plurality of time slots, the information is communicated using one time slot, and the other one time is transmitted. A closed wired communication system characterized in that the monitoring information is communicated using a slot.