JP2001237996A - Isdn terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a long life in a backup battery and high reliability in a system at a low cost in a method for constituting the backup battery circuit of an ISDN terminal. SOLUTION: In the terminal, the backup battery 1, the first contact point 6 and the second contact point 7 of a switch, which are serially arranged, and a battery voltage detecting circuit 9 are provided, and a terminal control circuit 4 monitors their states. Thus the useless consumption of the battery is prevented by a small scale circuit and forgetting turning-on the switch is detected when the ISDN terminal is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of an ISDN terminal connected to an ISDN line among automatic meter reading terminals usually called a T-NCU.

[0002]

2. Description of the Related Art Conventionally, in an automatic meter reading terminal connected to an ISDN line, a method of supplying power to a station or from an AC adapter has been adopted. Therefore, at the time of a power outage or when the line is disconnected by mistake, not only communication becomes impossible, but also various kinds of information to be held are lost instantaneously. In order to prevent this, a high energy density battery such as a lithium battery is mounted to back up the memory in some cases. However, unlike a conventional terminal for an analog line, a large amount of power is required in design in order to cope with the high speed of the ISDN line.

[0003] Such memory backup methods can be roughly classified into two types: a method of automatically switching to a battery when the power of a line or an AC adapter is cut off, and a method of manually switching to a battery. The former is an excellent method from the viewpoint of protecting information stored in the memory, but since the backup operation is continued from the time of manufacture to the time when the ISDN terminal is installed on site, battery consumption cannot be ignored. As a result, the battery life is shortened. In the latter method, the memory cannot be backed up due to a power failure or a momentary interruption of the line. In addition, if the power failure is resolved, it is necessary to manually switch from the battery to the line power supply or the AC adapter again manually.

FIGS. 5A and 5B show two specific examples of a memory backup circuit. In the case of FIG. 5A, when the power is turned off, the system automatically switches to a battery.
In the case of FIG. 5 (2), a switch 5 for switching the power supply is provided by a method of manually switching to a battery.

[0005]

However, in the above conventional configuration, the memory backup circuit configured as shown in FIG.
In the case of 4 kbps), the entire power consumption is large even in the standby mode in which no communication is performed. If the battery is consumed in this standby mode from the time the ISDN terminal is manufactured to the time it is installed at the site, the life of the battery after installation is greatly reduced.

Here, the standby mode is an operation mode for reducing the power consumption of the hardware constituting the circuit. For example, in the case of a microcomputer, it is realized by switching the operation clock to a low speed.

In FIG. 5 (2), since the switch 5 is manually switched to the battery side only in the event of a power failure or the like, it is impossible to hold various information stored in the memory when the line is momentarily interrupted. Further, if it is forgotten to manually switch from the battery (return of the switch) even after the power failure is resolved, the operation may be stopped in a short period of time due to unnecessary consumption of the battery.

As described above, it is an important issue to design a memory backup method suitable for ISDN terminals that does not cause unnecessary battery consumption and memory loss.

[0009]

In order to solve the above-mentioned problems, the present invention utilizes the characteristic of an ISDN line called station power supply, and performs terminal control when a power failure occurs or power is not supplied from a power supply line connected to an ISDN terminal. A backup battery that supplies power so that the circuit can perform the minimum necessary processing,
A switch is provided in series with the backup battery.

As a result, the battery is not consumed in a standby mode or the like from the time the ISDN terminal is manufactured to the time it is installed at the site, and the battery life can be extended. Furthermore, after installation, it is possible to detect the forgetting to turn on the switch for switching the backup battery, and to use the function of detecting the forgetting to switch on the battery and the battery voltage drop detection circuit.
The function of determining the operation state of the ISDN terminal can be easily realized,
It also contributes to performance improvement and cost reduction of the whole system such as automatic meter reading.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is characterized in that a backup battery for supplying power so that the terminal control circuit can perform necessary minimum processing when a power failure occurs or there is no power supply from a power supply line connected to the ISDN terminal. , A switch is provided in series with the backup battery.

[0012] Thus, in a power supply section of an ISDN terminal configured to perform a backup process using a battery at the time of an instantaneous line interruption or an AC power failure, a switch provided in series with the battery is turned on at the time of installation. ISD
Battery consumption can be eliminated in a standby mode or the like from the time when the N terminal is manufactured to the time when it is installed at the site, and it is not necessary to manually switch from the battery after the power outage is resolved (switch recovery).

According to a second aspect of the present invention, a second contact is provided in conjunction with the first contact of the switch, and this contact information is output to a terminal control circuit.

Thus, by notifying the state of the switch to the terminal control circuit through the second contact point, the state of the power supply is instantaneously determined, and the terminal control circuit performs an optimal operation. Can inform the person in charge of the installation work.

According to a third aspect of the present invention, a battery voltage detecting circuit for the backup battery is provided after the first contact of the switch, and the output of the battery voltage detecting circuit is input to the terminal control circuit to determine the state of the switch and the battery voltage. It is possible to simultaneously detect the decrease.

Thus, by notifying the terminal control circuit of the second contact for informing the state of the switch and the output of the battery voltage detection circuit, the state of the power supply can be instantaneously determined, and the terminal control circuit operates optimally. And, if necessary, inform the person in charge of the installation work through the center.

According to a fourth aspect of the present invention, there is provided a line voltage detection circuit for a power supply line connected to an ISDN terminal, and the output of the line voltage detection circuit and the second contact information of the switch are input to a terminal control circuit. This is to determine whether the state of the power supply line is normal or the state of power failure or line disconnection.

Thus, the second contact for informing the terminal control circuit of the state of the switch, and the output of the battery voltage detection circuit and the output of the line voltage detection circuit are notified to the terminal control circuit, so that the state of the power supply can be instantaneously determined. As a result, the terminal control circuit performs an optimal operation, and if necessary, the information can be notified to the person in charge of the installation work through the center.

For example, after installation, notification to the center via a line can improve the life and reliability of the system. Compared to conventional ISDN terminals that switch unconditionally to a backup battery during a power outage or manually switch to a backup battery, it can be activated only when a power backup is required, and the switching when the power is turned off is also automatic. is there. Furthermore, since it is possible to detect and prevent forgetting to turn on the backup switch and to notify the center of the external power supply status, it is possible to improve the service life of ISDN terminals and improve the reliability as a system for automatic meter reading. Become.

[0020]

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

(Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention. In the figure, first, the flow of power supply and the operation of each block will be described for the period from when the ISDN terminal is manufactured to when it is installed.

During this period, since the line is not connected,
Turning off the switch 6 prevents unnecessary consumption of the battery 1 in the terminal control circuit 4.

Next, the flow of power supply and the operation of each block after the ISDN terminal is installed will be described.

Since the ISDN line is supplied to the station, the DC voltage of +40 V input from the network via the line is converted by the DC / DC converter 3 into a voltage (for example, +5 V) suitable for the terminal control circuit 4 to prevent backflow. Is supplied to the terminal control circuit 4 through the diode 2 of FIG. At this time, the switch 6 is turned on, but if the output voltage of the DC / DC converter 3 is set higher than the battery voltage, the diode 2 on the battery side is turned off, and power is not supplied from the battery 1. Thus, unnecessary consumption of the battery 1 can be prevented. If the line voltage drops due to a power failure or line disconnection, DC /
Since the output of the DC converter 3 drops to 0V, the diode 2 on the battery side turns on, and power is supplied from the battery 1 to the ISDN terminal such as the terminal control circuit 4. The backup by the battery 1 enables the ISDN terminal to continue the minimum necessary processing such as holding the memory contents and monitoring the state by the microcomputer.

In the figure, the switch 6 is inserted on the positive electrode side of the battery, but the same effect can be obtained by inserting it on the negative electrode side.

(Embodiment 2) Embodiment 2 will be described with reference to FIG. In the figure, the basic flow of power supply and the operation of each block are the same as those in the first embodiment.
The second contact 7 of the switch 6 that switches on / off complementarily in conjunction with the switch is provided. For example, when the first contact of the switch 6 is on, the contact 7 is off, and when the first contact 6 is off, the contact 7 is on. The terminal control circuit 4 can recognize the state of the switch 6 for connecting / disconnecting the backup battery 1 based on the contact information.

This is to detect that the switch 6 is not turned on by the second contact 7 and to generate some kind of warning, since the switch 6 may be forgotten to be turned on during the terminal installation work. . As a method of this warning, for example, at the time of installation, when performing initial setting of various data in the ISDN terminal, the fact is displayed on a display device of a device (setting device) for performing setting, or a sound such as a buzzer sounds. Is also good. Further, the setting may not be advanced.

As a result, it is possible to prevent wasteful consumption of the backup battery, prolong the battery life, and ensure reliable construction quality.

It is needless to say that the same effect can be obtained even if the contact 7 is turned off when the first contact of the switch 6 is turned on and the contact 7 is turned off when the first contact 6 is turned off. Absent.

(Embodiment 3) Embodiment 3 will be described with reference to FIG. In the figure, the basic flow of power supply and the operation of each block are the same as those of the second embodiment, but a battery voltage detection circuit 9 is provided immediately after the switch 6 of the backup battery 1. The battery voltage detection circuit 9 is configured by combining a normal comparator and a reference voltage circuit, for example. As a result, the battery voltage applied to the anode of the diode 2 on the backup battery side is detected, and one detection circuit can have both functions of ON / OFF detection of the switch 6 and detection of a battery voltage drop. Furthermore, the terminal control circuit 4 cannot determine whether the battery voltage has been consumed or the switch 6 has been forgotten to be turned on by the output of the battery voltage detection circuit 9 alone. Is configured so that the terminal control circuit 4 can recognize the state of the terminal control circuit 4.

Here, the battery voltage drop detecting function is as follows.
A function that constantly monitors the battery voltage drop on the ISDN terminal side and, if it falls below a certain value, notifies the center to that effect and prevents the meter reading function of the ISDN terminal from stopping before it happens. is there. Conventionally, a dedicated battery voltage drop detection circuit is provided. However, in the present invention, it is possible to reduce the entire circuit scale by making the detection circuit also have a function of detecting that the switch 6 has been turned on. Further, the terminal control circuit 4 can determine whether the battery voltage has dropped or whether the switch 6 has been forgotten to be turned on by monitoring the second switch contact 7.

(Embodiment 4) Embodiment 4 will be described with reference to FIG. In the figure, the basic flow of power supply and the operation of each block are the same as those of the third embodiment, but DC / DC
The line voltage detection circuit 10 is provided immediately after the output of the converter 3. The line voltage detection circuit 10 is configured by, for example, combining a normal comparator and a reference voltage circuit. Thereby, the line voltage applied to the anode of the diode 2 on the DC / DC converter side is detected and notified to the terminal control circuit 4. Thus, the supply voltage abnormality at the time of power failure or line disconnection can be detected at the same time, so that the terminal control circuit 4 can determine whether the power failure or line disconnection or normal operation is occurring.

Here, the term "power failure" means a state where it is impossible to supply DC +40 V from the S / T point of the line at the time of a power failure when the power supply is connected to a DSU operating on AC power. The line disconnection means that the wiring at the point U or the S / T point is disconnected for some reason, the power supply to the station is stopped, and the communication path is opened to disable communication.

The terminal control circuit 4 constantly monitors the supply voltage from the line to determine whether the communication failure is caused by a power failure or line disconnection or another cause. It is possible to report to the center.

In this way, even if the output of the battery voltage detection circuit 9 is normal and the output of the second contact 7 of the switch is normal, the line voltage detection circuit 1
By monitoring the output level of 0, the state of power supply from the line can be determined. If it is known based on the output level of the line voltage detection circuit 10 that the power supply to the station has stopped, the terminal control circuit 4 is shifted to the standby mode after a certain period of time, thereby reducing the current consumption of the battery.

Here, the standby mode is an operation mode for reducing the power consumption of the hardware constituting the circuit. For example, in the case of a microcomputer, it is realized by switching the operation clock to a low speed.

Although not shown, according to the present embodiment, a storage means for storing the situation of power failure or line disconnection in the ISDN terminal is provided, and when the system is restored, the center is notified to that effect, so that system maintenance can be performed. It becomes easy and reliability can be improved.

Although not shown, a third switch circuit that can be remotely controlled from the center of the system is provided in parallel with the switch circuit configured as described above, so that if the backup switch is forgotten to be turned on, The backup by the battery can be realized without going to the factory. In addition, by providing a fourth switch circuit that can be remotely controlled from the center side in series with the switch circuit, even if there is no response due to relocation or the like, the backup battery can be cut off without going to the site to eliminate unnecessary batteries. Wear can be prevented.

In each of the embodiments described above, the ISDN terminal that operates exclusively with station power supply is premised, but the present invention is also applicable to an ISDN terminal that operates with an AC power supply using an AC adapter. In this case, the DC / DC converter 3 in each embodiment shown in FIGS. 1 to 4 may be replaced with an AC adapter.

[0040]

As described above, according to the present invention, there is provided a backup battery for supplying power so that the terminal control circuit can perform the necessary minimum processing at the time of a power failure or when there is no power supply from the power supply line connected to the ISDN terminal. Since the switch is provided in series with the backup battery, the battery is not consumed in a standby mode or the like from the time the ISDN terminal is manufactured to the time it is installed at the site, and the battery life can be extended. Further, after installation, it is possible to prevent forgetting to turn on the switch for switching the backup battery, and at the same time, it can serve both as a function to detect forgetting to switch on and a battery voltage drop detection circuit. Therefore, the function of determining the operation state of the ISDN terminal can be easily realized, which contributes to improvement of the performance of the entire system such as automatic meter reading and cost reduction. As described above, by providing the switch in series with the backup battery, the life of the battery can be extended, and the quality of installation work and the reliability of the system can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an ISDN terminal according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of an ISDN terminal according to a second embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of an ISDN terminal according to a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of an ISDN terminal according to a fourth embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of an ISDN terminal showing a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Backup battery 4 Terminal control circuit 6 Switch or its first contact 7 Second contact of switch 9 Battery voltage detecting means 10 Line voltage detecting means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shiro Honma 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Terms (reference) 5G003 DA03 EA06 GB03 5K027 AA10 BB17 CC02 FF14 GG03 GG06 5K037 AA10 AA13 AB01 AC05 BA03 DA06

Claims (4)

[Claims] A backup battery for supplying power so that the terminal control circuit can perform necessary minimum processing when a power failure occurs or power is not supplied from a power supply line; and a switch connected in series with the backup battery. ISDN terminal provided with. 2. The ISDN terminal according to claim 1, further comprising a second contact interlocking with the first contact of the switch, and outputting the contact information to a terminal control circuit. 3. A battery voltage detection circuit for a backup battery is provided after a first contact of a switch, and an output of the battery voltage detection circuit is input to a terminal control circuit to simultaneously detect a switch state and a battery voltage drop. 3. I according to claim 2, wherein
SDN terminal. 4. A line voltage detection circuit for detecting a voltage of a power supply line is provided, and an output of the line voltage detection circuit and second contact information of a switch are input to a terminal control circuit, and the state of the power supply line is normal. 4. The ISDN according to claim 3, wherein the determination is made.
Terminal.