JPH11205477A - Terminal network controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To immediately report an emergency from a gas meter or the like connected to a terminal network controller at all times in the case of attaching the terminal network controller to an ISDN public line. SOLUTION: This controller is provided with an S/T point bus 12 for connecting the S/T point of a DSU which is an interface with the ISDN public line and transmitting signals, a terminal communication means 11 for connecting a terminal 10 and performing communication with the ISDN public line through the S/T bus 12 and an S/T point disconnection control means 13 for connecting ISDN communication terminals 2 and 14, controlling the connection and disconnection of the ISDN communication terminals 2 and 14 and the S/T bus 12 and controlling terminating resistance. By disconnecting the downstream SAT point bus 12 by the S/T point disconnection control means 13, a communication channel is surely secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal network control device for communicating terminal devices such as meter reading meters and equipment with a remote management device via an ISDN public line.

[0002]

2. Description of the Related Art Automatic meter reading of an energy supply management device (for example, a gas meter, a water meter, a power meter) from a remote management device using a telephone network, notification of a gas leak to the remote management device, and failure notification of equipment. Systems for performing remote diagnosis and the like are becoming widespread.

[0003] Further, ISDN telephone lines have begun to spread, and introduction to general households for accessing personal computer communication and the Internet has also become active. The general system configuration is such that a digital line terminator (hereinafter referred to as a DSU) is connected to a two-wire metal cable drawn from the ISDN public line to the house via a protector, and transmission such as two-wire to four-wire conversion is performed. The end of the road is done and IS
Connect a digital telephone for DN,
An adapter (hereinafter referred to as TA) is connected to perform protocol conversion, and is connected to a terminal device such as a personal computer using an RS-232C cable or the like. At NTT (Nippon Telegraph and Telephone Corporation), the reference point is the interface from the protector to the DSU. The reference point is the interface from the DSU to the telephone or TA. The reference point is the interface from the S / T, and the interface from the TA to the terminal equipment such as a personal computer. Called R. In addition, S /
The T point is an IS defined in Recommendation I.411.
DN user-network interface point, R point is ITU
-An existing user / network interface point defined in T Recommendation V, X series, etc.

[0004] In the ISDN public line, 8 is used for the S / T point bus.
Up to 400 communication terminals can be connected, and the power that can be transferred from the line is up to 400 mW (380 mW for one designated terminal, 20 mW for the other terminals), and the operating power of the communication terminal is In case of exceeding the above, it is necessary to supply an external power source such as a commercial power source or a battery. For this reason, Japanese Patent Laid-Open Publication No. 2-58497 discloses a telephone device connected to a main device as a method for performing communication of the telephone device via an ISDN public line even during a power failure. As shown in FIG. 4, the system comprises a main unit 1 connected to an S / T point of an ISDN public line, one ISDN-compatible telephone 2 connected to the main unit 1, and a plurality of analog telephones 3. You. Normally, the switching unit 5 is controlled by the CPU 4 of the main unit 1 to control the telephone line, the ISDN-compatible telephone 2 and the analog telephone 3
Communicate between At this time, the operating power of the main apparatus 1 and the operating power of the ISDN-compatible telephone 2 are supplied from an external power supply 6 composed of a commercial power supply or the like. However, CPU
When the ISDN telephone 4 detects a voltage drop due to a power failure of the external power supply 5, the switch 7 switches the ISDN-compatible telephone 2 so as to be directly connected to the ISDN public line.
Can transmit and receive power from the line power even during a power outage and communicate with the outside via the ISDN public line.

Further, of the communication terminals connected to the S / T point bus, the inside of the communication terminal furthest from the DSU or the connector connecting the communication terminal is terminated with a terminating resistor.

Further, two 64 Kbits are used in the ISDN line.
Data communication can be performed by circuit switching communication or packet communication using a B / s B channel and packet communication using a 16 Kbit / s D channel. For this reason,
For example, even if one B channel is in use, communication can be performed using the other B channel.

[0007]

When the above conventional method is used for a terminal network control device, there are the following problems.

(1) In order to eliminate the influence of other terminals at the time of operation confirmation when the terminal network control device is connected to the telephone line at the customer's house, all other terminals are temporarily disconnected from the telephone line. If the terminal network controller is not the farthest end from the DSU at that time, it is necessary to add a new terminating resistor.

(2) Unless the terminal network control device is designated as a designated terminal, almost no power can be exchanged from the telephone line. If the power cannot be supplied from the outside such as a commercial power supply during a power failure, the terminal network control device does not operate. The emergency call from the terminal device cannot be transmitted.

(3) When another communication terminal of the customer's house is in use, there is a case where there is no available channel, so that a report from a terminal device connected to the terminal network control device cannot be transmitted immediately.

[0011]

According to the present invention, there is provided an S / T for transmitting a signal by connecting an S / T point of a DSU which is an interface to an ISDN public line.
A point bus, terminal communication means for connecting a terminal device and communicating with an ISDN public line via the S / T bus,
N communication terminals, and the ISDN communication terminal and the S /
S / T point disconnection control means for controlling connection and disconnection with the T point bus and controlling the terminating resistance is provided.

According to the above invention, since the downstream S / T point bus can be disconnected by the S / T point disconnection control means, the communication of the terminal device on the telephone line can always be ensured.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an S / T point bus for connecting an S / T point of a DSU, which is an interface to an ISDN public line, and transmitting a signal, and connecting the terminal device to the S / T point bus.
Terminal communication means for communicating with an ISDN public line via a / T bus, connecting and disconnecting the ISDN communication terminal to and from the S / T point bus and controlling a terminating resistor S / T point cutting control means. Then, the communication of the terminal network control device can be reliably performed by separating the downstream communication terminal by the S / T point disconnection control means.

[0014] Further, there are provided external power supply means for receiving predetermined power and supplying predetermined power to each section, and line power supply means for receiving power of a telephone line and supplying predetermined power to each section.
The external power supply means transmits an S / T point disconnection request signal to the S / T point disconnection control means and transmits a power supply request signal to the line power supply means when power supply from the outside is stopped. Then, the terminal network control device can perform communication using power from the telephone line.

Further, the terminal communication means requests the ISDN public line for communication using the B channel and
S when receiving notification that B channel is in use from N public line
It transmits an S / T point disconnection request signal to the / T point disconnection control means. Then, the terminal network control device can perform communication while securing the B channel.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram of a terminal network control device according to a first embodiment of the present invention. In the figure, reference numeral 8 denotes a terminal network control device. Reference numeral 9 denotes a DSU, which is an entrance / exit for signals from the ISDN public line to the customer's home. The terminal network controller 8 connects to the S / T point interface of the DSU 9.
Reference numeral 10 denotes a gas meter as a terminal device. Reference numeral 11 denotes a terminal communication means, which is connected to the gas meter 10 and connects to the S / T point bus 1
2 and communicate with the ISDN public line. 13 is S /
The S / T point bus 12 is connected to an external ISD
It connects / disconnects with an S / T point for connection to an ISDN-compatible telephone 2 or a terminal adapter 14 which is an N communication terminal, and further adds a terminating resistor to an end point of the S / T point bus 12 at the time of disconnection. It can be operated externally as a switch. In the figure, a terminal resistor is installed in the connector of the terminal adapter 14 when an external communication terminal is connected. Further, in the terminal network control device 8, power of each unit is supplied by a battery.

In the above configuration, when communication is performed with the gas meter 10 to perform a test of the terminal network control device 8, the switch of the S / T point disconnection control means 13 is operated to allow the terminal network control device 8 to operate. The downstream S / T point bus is disconnected to terminate the line resistance of the S / T bus 12, and the ISDN compatible telephone 2 and the terminal adapter 14 connected downstream are connected.
The communication via the ISDN public line can be immediately performed from the gas meter 10 irrespective of the state.

The operation of the S / T point disconnection control means is not limited to an external switch operation. The terminal communication means in the terminal network control device can detect a disaster such as an earthquake, and can report from a terminal device such as a gas meter. Can be promptly notified in an emergency.

(Embodiment 2) FIG. 2 is a block diagram of a terminal network control apparatus according to Embodiment 2 of the present invention. In the figure, the difference from the first embodiment is that an external power supply means 15 is provided, and power is supplied to each unit of the terminal network control device 8 using a commercial power supply of a customer's house in normal times. A line power supply unit 16 can also supply power to each unit of the terminal network control device 8 with line power from an ISDN public line.

With the above configuration, in normal times, the ISDN-compatible telephone 2 operates as a designated terminal with line power from the ISDN public line, and the terminal network control device 8 operates with power supplied from a commercial power supply. However, when the power supply from the commercial power supply is lost (that is, the power is cut off), S / S
The T point disconnection control means 13 detects a drop in the power supply voltage and
The / T point bus 12 is disconnected from the ISDN compatible telephone 2 as an external communication terminal, and a terminating resistor is added to an end point of the S / T point bus 12. Further, the line power supply means 16 starts supplying power to each unit of the terminal network control device 8 from the line power. With the above operation, the terminal network control device 8 can stably supply power even in the event of a power outage, so that communication with the gas meter 10 becomes possible, so that an emergency call can always be made.

(Embodiment 3) FIG. 3 is a block diagram of a terminal network control apparatus according to Embodiment 3 of the present invention. In the figure, the difference from the first embodiment is that the terminal communication unit 11 requests the ISDN public line to perform communication using the B channel and
When a notification that the B channel is in use is received from the public line, S /
It has a function of sending an S / T point disconnection request signal to the T point disconnection control means 13.

With the above configuration, the ISDN telephone 2 and the terminal adapter 14 are normally connected to the S / T point to communicate with the ISDN public line in normal times. Here, when a report request is sent from the gas meter 10 to the terminal communication means 11 to make an emergency report such as a gas leak, the terminal communication means 11 requests the ISDN public line to start communication using the B channel. . At this time, when the terminal communication means 11 receives a notification indicating that the B channel is in use from the ISDN public line, the terminal communication means 11 determines that the ISDN-compatible telephone 2 and the terminal adapter 14 are using all the B channels and performs S / T point disconnection control. An S / T point disconnection request signal is sent to the means 13. The S / T point disconnection control means 13 is connected to the S / T point bus 12
Is disconnected from the external communication terminal, and the S / T point bus 12
A terminating resistor is added to the end point of. By the above operation, the B channel in use is released, so that the terminal network control device 8 can immediately make an emergency call from the gas meter 10.

[0024]

According to the terminal network control device of the present invention as described above, the following effects can be obtained.

(1) The S / T point disconnection control means disconnects the S / T point bus downstream from the terminal network control device and terminates the S / T bus, so that another communication terminal of the customer's house can be connected to the S / T. The communication with the ISDN public line of the terminal network control device can be performed in a state where the terminal network control device is not affected by the other terminals separated from the point bus.

(2) Even if the terminal network control device is not designated as a designated terminal, if power cannot be supplied from the outside such as a commercial power supply during a power failure, the S / T point bus downstream from the terminal network control device is disconnected and S / T By terminating the T bus, the terminal network control device can operate by supplying power from the ISDN public line, and thus can transmit an emergency notification from the terminal device.

(3) Even if another communication terminal of the customer's home is in use and there is no usable channel, the S / T point is disconnected by the terminal communication means at the time of an emergency call from the terminal device connected to the terminal network control device. By notifying the control means and disconnecting the S / T point bus downstream from the terminal network control device and terminating the S / T bus, the emergency notification from the terminal device even when another communication terminal of the customer's house is in use. Is not late.

[Brief description of the drawings]

FIG. 1 is a block diagram of a terminal network control device according to a first embodiment of the present invention;

FIG. 2 is a block diagram of a terminal network control device according to a second embodiment of the present invention;

FIG. 3 is a block diagram of a terminal network control device according to a third embodiment of the present invention;

FIG. 4 is a block diagram of a telephone device using a main device connected to a conventional ISDN public line.

[Explanation of symbols]

 2 Telephone for ISDN (ISDN communication terminal) 8 Terminal network control device 9 DSU 10 Gas meter (terminal device) 11 Terminal communication means 12 S / T point bus 13 S / T point disconnection control means 14 Terminal adapter (ISDN communication terminal) 15 External Power supply means 16 Line power supply means

Claims (3)

[Claims] 1. An S / T point bus for connecting an S / T point of a DSU, which is an interface to an ISDN public line, to transmit a signal, and connecting a terminal device to the ISDN via the S / T point bus. Terminal communication means for communicating with a public line, and ISD
N communication terminals, and the ISDN communication terminal and the S /
A terminal network control device comprising S / T point disconnection control means for controlling connection and disconnection with a T point bus and controlling a terminating resistance. 2. An external power supply comprising: external power supply means for receiving external power and supplying predetermined power to each unit; and line power supply means for receiving telephone line power and supplying predetermined power to each unit. When the power supply from the outside is stopped, S /
The terminal network control device according to claim 1, wherein an S / T point disconnection request signal is transmitted to the T point disconnection control means, and a power supply request signal is transmitted to the line power supply means. 3. The terminal communication means requests the ISDN public line for communication using the B channel and, upon receiving a notification indicating that the B channel is being used from the ISDN public line, sends the S / T point disconnection control means to the S / T point disconnection control means. 2. A point disconnection request signal is transmitted.
The terminal network control device as described in the above.