JP2831699B2 - Data transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a terminal device connected to one end of a communication line via a network control device and a center connected to the other end of the communication line. The present invention relates to a data transmission apparatus that calls a partner apparatus from any of a terminal apparatus and a center apparatus and performs bidirectional data transmission with the apparatus.

(Prior Art) In a data transmission device of this type, a terminal device and a network control device for the terminal are connected by two wires, and when performing two-way communication by no ringing communication and terminal calling, The voltage start method is used. Specifically, the connection between the terminal device and the network control device is established between the transmission transistors 101 and 201 provided in the terminal device 100 and the network control device 200, respectively, as shown in FIG. This is done by directly connecting the grounds with two transmission lines 300 (DT, SG). In addition, both devices 100, 2
00 has switches 103 and 203 for supplying the voltage VDD to the transmission transistors 101 and 201, respectively, and activates the terminal device 100 from the network control device 200 via this switch, and the communication transmitted from the center device (not shown). The communication is terminated by notifying the terminal device 100 of the end signal from the network control device 200.

Now, for the case of no ringing communication,
When the network control device 200 receives the no-ringing incoming signal and the terminal start command data from the center device via the communication line, it turns on its own switch 203 and supplies the voltage from the network control device 200 to the terminal device 100 to start. I do. When the terminal device 100 detects the starting voltage from the network control device 200, the terminal device 100 performs transmission by turning on / off the transmission transistor 101. Further, in the communication from the center device to the terminal device, the transmission transistor 201 of the network control device 200 is turned on / off by a transmission signal from the center device to perform transmission. Then, at the end of the communication, the center device releases the line, whereby the polarity of the line is restored, so that the network control device 200 detects this and turns off the switch 203, whereby the network control device 200 100 is notified of the end of communication. That is, the network control device 200 notifies the end of communication by turning off the switch 203 and thereby turning off the voltage to the terminal device 100 via the transmission line 300.

By the way, in the conventional circuit shown in FIG. 7, a terminal device and a network control device are directly connected via a transmission transistor. A method of connecting with a coupler has been proposed. In this connection method, since the terminal device and the network control device are completely electrically separated from each other, the terminal device can have a complete explosion-proof structure, while at the same time improving the noise resistance of the signal circuit and improving the system. There is a merit that lightning resistance can be improved. Further, in the method of connecting the two with the photocoupler, signals are exchanged between the two depending on whether or not a current flows through the transmission line via the photocoupler, that is, whether or not the current is present.

(Problems to be Solved by the Invention) In a method of connecting between a terminal device and a network control device using a photocoupler, a transmission signal between the two is determined by the presence or absence of a current flowing through a transmission line via the photocoupler. In the transmission and reception of such a signal, the presence or absence of current is used for the transmission signals 1 and 0, and even during non-communication such as at the time of non-activation and after the end of communication,
Even when there is no transmission signal after activation, there is no current flowing through the transmission line, so there is no distinction between non-communication and when there is no transmission signal after activation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a data transmission device for quickly and accurately notifying the end of communication.

[Structure of the Invention] (Means for Solving the Problems) To achieve the above object, a data transmission device of the present invention is connected to one end of a communication line via a network control device as shown in FIG. Data transmission that performs bidirectional data transmission in the same communication procedure by calling a partner device from either the terminal device or the center device between the terminal device and the center device connected to the other end of the communication line. A device, provided in the network control device, a photocoupler interface that connects a data transmission path to the center device and a data transmission line to the terminal device in a non-contact manner, provided in the terminal device, Transfer means for alternately switching data transmission to the center device or data reception from the center device; and a transfer unit provided in the center device for performing the same communication procedure. Transmission end information transmitting means for transmitting transmission end information to the terminal device via a communication line and the network control device when a final response signal is transmitted from the terminal device during bidirectional data transmission. That is the gist.

(Operation) In the data transmission device of the present invention, in the network control device,
The data transmission line to the center device and the data transmission line to the terminal device are connected by a photocoupler interface, and both the center device and the terminal device call the other device and perform the same communication procedure. When a final response signal is transmitted from the terminal device at the time of data transmission in the transmission direction, the transmission end information is transmitted from the center device to the terminal device via the communication line and the network control device.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing a configuration of a data transmission device according to one embodiment of the present invention. The data transmission device shown in FIG. 1 includes a center device 1 and a terminal-side network control device 5 connected via a center-side network control device 2 to each end of telephone lines 3a and 3b connected via a telephone exchange 3. This is a device that performs data transmission with a plurality of terminal devices 6 that are connected to each other via the. More specifically, the data transmission device is a meter in which the terminal device 6 measures the usage of gas, water, electricity, or the like, for example, and a data collection device that collects data measured by the meter in the center device 1. The data transmission device calls each terminal device 6 with no ringing termination, and each terminal device 6 calls the center device 1 by a terminal calling operation, and performs bidirectional data communication between the two. At the end of communication, a data transmission end message is transmitted from the center apparatus 1 to the terminal apparatus 6, and when the terminal apparatus 6 detects this, a series of data transmission processing is ended. A no-ringing trunk 4 is connected to the exchange 3 in order to perform a no-ringing termination from the center device 1 to the terminal device 6, and as shown in FIG. 4 described later, the terminal-side network control device 5 and the terminal device 6 Are connected by a photocoupler.

FIG. 3 is a block diagram showing the configuration of the terminal-side network control device 5. The terminal-side network control device 5 shown in the figure has an output side connected to the telephone line 3b, and an automatic transmission network control unit 11 for making a terminal call, and is connected in parallel to the automatic transmission network control unit 11, A no-ringing incoming network control unit 12 for receiving a no-ringing incoming call from the center device 1 and an input terminal of the automatic outgoing network control unit 11 for demodulating a signal from the center device 1 and for transmitting a signal to the center device 1 , A signal switching unit 15, a serial data input / output unit 16, a CPU 13 for controlling the overall operation, and one end connected to the terminal device 6 via the connection line 7, and the other end connected to the signal terminal. It is connected to the switching unit 15 and comprises a two-wire to four-wire conversion unit 17 for converting two lines of the connection line 7 into four lines.

FIG. 4 is a circuit diagram showing an interface section between the terminal device 6 and the terminal-side network control device 5 connected via the connection line 7. The connection line 7 is composed of two lines consisting of a DT line and an SG line.
The connection line 7 is connected back to the SG line via the phototransistor 21t, and the connection line 7 is connected to the movable contact of the transfer switch 23 and the SG line is connected to the movable contact of the transfer switch 25 in the terminal device 6. Have been. The break contact of the transfer switch 23 is connected to ground, and the make contact is connected to the voltage VDD via a resistor. The make contact of the transfer switch 25 is connected to the ground, the break contact is connected to the voltage VDD via a resistor, and to the input of the receiving buffer 27.

Further, in the terminal-side network control device 5, both ends of the connection line 7, ie, the phototransistor 21t of the photocoupler 21,
The light emitting diode 29d of the photocoupler 29 is connected in parallel with the light emitting diode 29d. The light emitting diode 21d of the photocoupler 21 receives a signal transmitted from the center device 1, and the phototransistor 29t of the photocoupler 29 transmits a signal received by the center device 1. The terminal-side network control device 5 and the terminal device 6 thus connected by the connection line 7
Are electrically separated by a photocoupler 21 and a photocoupler 29.

 Next, the operation will be described.

The operation at the time of no ringing communication will be described with reference to FIGS. FIG. 5 (a) is a data communication timing chart at the time of no ringing communication, and FIG. 5 (b)
Indicates a data transmission procedure at the time of no ringing communication.

First, when the center device 1 activates the exchange 3 and performs no-ringing communication, the exchange 3 captures the no-ringing trunk 4 and inverts the polarity of the telephone line via the no-ringing trunk 4 to the terminal-side network control device 5. A no-ringing incoming call is performed (process S100 in FIG. 5B). When the terminal-side network control device 5 detects the no-ringing incoming call and returns a response signal to the exchange 3, the exchange 3 further returns the response of the terminal-side network control device 5 to the center device 1 with the polarity reversed (process S110). ).

A response signal is returned to the center device 1 and the center device 1
When the telephone line between the terminal device and the terminal-side network control device 5 is completely connected, the center device 1 transmits terminal activation command data to the terminal-side network control device 5. Upon receiving the terminal start command data, the terminal side network control device 5 starts the photocoupler 21 as shown in FIG. 5 (a) as a terminal start signal and activates the phototransistor 21t of the photocoupler 21. Is turned on, thereby activating the terminal device 6 via the connection line 7 (process S120).

In this start-up operation, when the phototransistor 21t of the terminal side network control device 5 is turned on, the connection portion 7 receives the voltage from the voltage VDD via the break contact of the transfer switch 25 of the terminal device 6, the SG line of the connection line 7, As shown in (d) of FIG. 5 (a), the phototransistor 21t of the network control device 5, the DT line of the connection line 7, and the ground path via the break contact of the transfer switch 23 of the terminal device 6 are activated. Electric current flows. This start-up current is detected via the reception buffer 27 of the terminal device 6, whereby the terminal device 6 is started.

When the terminal device 6 is activated, the terminal device 6 transmits its own data, such as meter reading data when the terminal device 6 is a gas, water, electricity meter, or the like, to the terminal-side network control device 5, the exchange 3, and the center-side network control. Transmitted to the center device 1 via the device 2,
Communication is started (process S130). That is, in this transmission operation, the terminal device 6 operates its own transfer switch 25, closes the make contact and supplies the ground from the transfer switch 25, and in this state, the terminal device 6 outputs the meter reading data as shown in (b) of FIG. This is performed by turning on / off the transfer switch 23 as shown. Transfer switch 23 is on /
When the terminal is turned off, a current flows from the voltage VDD of the terminal device 6 to the connection line 7 as the meter reading data in (d) of FIG. The photo coupler 29 is turned on / off, and this on / off signal is transmitted from the terminal side network control device 5 to the center device 1 as transmission data as described above.

When receiving the data from the terminal device 6, the center device 1 transmits the electronic message 1 to the terminal device 6. The terminal device 6 returns a response signal 1 to the message 1 to the center device 1.
Hereinafter, the same operation is repeated until the center device 1 transmits the message n and the terminal device 6 returns the response signal n (step S140).

When the transmission and reception of all telegrams and response signals are completed, the center device 1 transmits transmission end data to the terminal device 6. When receiving the transmission end data, the terminal device 6 restores the transfer switches 23 and 25 and immediately returns to the center device 1.
Then, the transmission process between the steps is terminated (process S150).

On the other hand, when the center device 1 transmits the transmission end data to the terminal device 6, the center device 1 performs a line restoration operation for the exchange 3. In response to this recovery operation, the exchange 3 recovers the polarity reversal for the terminal side network control device 5 and also recovers the polarity reversal for the center device 1, thereby releasing the telephone line that has been captured (processing S160).

Next, the operation of the terminal call communication will be described with reference to FIGS. 6 (a) and 6 (b).

FIG. 6 (a) shows the timing from when the terminal device 6 calls the center device 1 at the time of a terminal call and when the terminal device 6 is activated from the center device 1, and FIG. 6 (b) shows the terminal call communication. A series of data transmission procedures at the time is shown.

First, in order to call the center device 1, the terminal device 6 turns on the transfer switch 23 of the terminal device 6 as shown in (b) of FIG.
When the transfer switch 25 is turned off, a current flows to the photocoupler 29 of the terminal-side network control device 5 via the connection line 7 as shown in FIG. , The terminal device 6 turns on and off the transfer switch 23, and the telephone number of the center device 1 is shown in (b) and (d) of FIG. 6 (a). Is transmitted to the terminal-side network control device 5 (process S200 in FIG. 6B).

Upon receiving the call and the telephone number from the terminal device 6, the terminal side network control device 5 closes the loop of the telephone line, activates the exchange 3, and receives a dial tone from the exchange 3. Upon receiving the dial tone from the exchange 3, the terminal-side network control device 5 transmits the telephone number of the center device 1, that is, the dial number, received from the terminal device 6 (process S210).

When the exchange 3 receives the telephone number of the center device 1 from the terminal-side network control device 5, it transmits a calling signal to the center device 1 and simultaneously returns a ringing tone to the terminal-side network control device 5 (step S220).

When called by a call signal from the exchange 3, the center device 1 closes the loop of the telephone line. When the center device 1 closes the loop of the telephone line, the exchange 3 detects this and inverts the polarity of the telephone line to the terminal side network control device 5 (process S230). Further, following this operation, the center device 1 transmits an incoming response signal to the terminal side network control device 5 via the exchange 3. When the terminal-side network control device 5 receives the incoming response signal from the center device 1, the photocoupler 21 is operated as shown in FIGS. To the terminal device 6
Is started (process S240).

When the terminal device 6 starts, it transmits, for example, security information to the center device 1 and starts communication. Less than,
As in the case of the above-mentioned no-ringing communication, the telegram 1 is transmitted from the center device 1 to the terminal device 6, and the terminal device 6 returns the response signal 1 in response to the desired telegram n and the response signal n. Repeat (process S250).

When the transmission and reception of all telegrams and response signals are completed, the center device 1 transmits transmission end data to the terminal device 6. When receiving the transmission end data, the terminal device 6 restores the transfer switches 23 and 25 and ends the transmission process with the center device 1 (process S260).

On the other hand, when transmitting the transmission end data to the terminal device 6, the center device 1 releases the loop of the line to the exchange 3 and restores the polarity reversal to the terminal side network control device 5. The terminal-side network controller 5 releases the loop of the telephone line in response to the recovery from the polarity reversal (process S270).

[Effects of the Invention] As described above, according to the present invention, in a network control device, a data transmission line to a center device and a data transmission line to a terminal device are connected by a photocoupler interface, and the center device and the terminal When bidirectional data transmission is performed by calling the partner device from any of the devices and performing the same communication procedure, when a final response signal is transmitted from the terminal device, the communication line and the network control device are transmitted from the center device. Since the transmission end information is transmitted to the terminal device via the terminal device, for example, when the terminal device is a gas meter and the gas is shut off by a command from the center device, the gas shutoff operation can be quickly performed. it can. In both cases of calling from the center device to the terminal device and calling from the terminal device to the center device, the data transmission end information is transmitted from the center device to easily and accurately end the communication in the same procedure. can do.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the present invention, FIG. 2 is a block diagram showing an overall configuration of a data transmission device according to an embodiment of the present invention, and FIG. 3 is a terminal used in the data transmission device of FIG. FIG. 4 is a block diagram showing the configuration of the side network control device. FIG. 4 is a circuit diagram showing connection of an interface unit between the terminal device used in the data transmission device of FIG. 2 and the terminal side network control device. FIG. 6 is a diagram showing the operation of the data transmission device of FIG. 2 at the time of no ringing communication, FIG. 6 is a diagram showing the operation of the data transmission device of FIG. 2 at the time of calling a terminal, and FIG. FIG. 3 is a circuit diagram showing a connection with a control device. DESCRIPTION OF SYMBOLS 1 ... Center apparatus 3 ... Exchange 5 ... Terminal side network control apparatus 6 ... Terminal apparatus 7 ... Connection line 21, 29 ... Photocoupler 23,25 ... Transfer switch 99 ... Transmission end information transmission means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Nagano Uno 1-5-20 Kaigan, Minato-ku, Tokyo Inside Tokyo Gas Co., Ltd. (72) Chotaro Murakami 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Toshihiko Kawai 70, Yanagicho, Kochi-ku, Kawasaki, Kanagawa Prefecture Inside the Toshiba Yanagicho Plant (72) Inventor Yuji Mihara 70, Yanagicho, Yukicho, Kawasaki, Kanagawa Prefecture Co., Ltd. In the factory (72) Inventor Hiroto Uyama 70, Yanagicho, Yuki-ku, Kawasaki-shi, Kanagawa Prefecture In-house factory of Toshiba Yanagicho (56) References JP-A-62-173847 (JP, A) JP-A-52-146124 (JP JP-A-62-40895 (JP, A) JP-A-63-287247 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04M 11/00 H04L 5/16

Claims (1)

(57) [Claims] 1. A counterpart device between a terminal device connected to one end of a communication line via a network control device and a center device connected to the other end of the communication line from either the terminal device or the center device. A data transmission device that performs bidirectional data transmission in the same communication procedure by calling a data transmission line that is provided in the network control device and that reaches the center device and a data transmission line that reaches the terminal device. A photocoupler interface connected in a non-contact manner, transfer means provided in the terminal device for alternately switching data transmission to the center device or data reception from the center device, the transfer device being provided in the center device, When a final response signal is transmitted from the terminal device during bidirectional data transmission according to the communication procedure of Data transmission apparatus characterized by having a transmission end information transmission means for transmitting the transmission end information to the terminal apparatus via the network control unit.