JP2000295380A - Isdn terminal device and method for disconnecting connection to isdn line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the situation of temporary stop of ISDN service served to a terminal device without bringing about an increase in cost and making the device large when power feeding to the terminal device is stopped while the terminal device using an ISDN line communicates. SOLUTION: A terminal device utilizing an ISDN line is provided with detecting means 1 and 4 which detect that power feeding from a power supply is stopped during communication, a disconnecting means 4 which disconnects normally connection to the ISDN line on the basis of the stop detection of power feeding by the means 4 and 5 and a storing means 2 which feeds power at least for time needed to disconnect the connection to the ISDN line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ISDN (Inte
TECHNICAL FIELD The present invention relates to a terminal device using a grated services digital network), and more particularly to a device capable of normally disconnecting from an ISDN line when power supply is stopped during communication.

[0002]

2. Description of the Related Art In recent years, terminal devices such as telephones, video telephones, and video conference terminal devices provided with an interface for connecting to an ISDN line have become widespread. Also,
Existing terminal devices, such as telephones and computers, which do not have such an ISDN line interface, can use the terminal adapter for matching the interface conditions to the ISDN line interface.
Communication can be performed using an SDN line.

[0003] When communication is performed by using such an ISDN line with such a terminal device, when the communication is completed, the ISDN
Connection with line (connection on B channel or H channel)
Usually, a control signal for disconnecting the terminal is transmitted from the terminal device using the D channel, and the connection with the ISDN line is normally disconnected. That is, for example, in a video conference terminal device, an operation switch for disconnecting the connection is provided on a panel or the like, and by operating the switch, the connection with the ISDN line can be normally disconnected. ing.

[0004] However, if the supply of power to the terminal device is stopped during the communication, the connection to the ISDN line is not normally cut off, the operation of the terminal device is stopped, and the communication is interrupted. I will. For example, in a video conference terminal device, the supply of power is stopped during communication for the following reasons.

(1) Since an optical fiber cable subscriber line is provided with a primary rate interface as an ISDN line interface, power cannot be supplied (phantom power supply) from the exchange side. Because it is designed to use a commercial AC power supply,
This commercial power supply was interrupted during communication. (2) The power plug of the video conference terminal was accidentally unplugged from the outlet during communication. (3) The power switch of the video conference terminal device is turned off by mistake during communication.

[0006] When the communication is interrupted without disconnecting the connection to the ISDN line normally, the telecommunications carrier providing the ISDN service determines that a failure has occurred in the terminal device. In order to prevent an extra load from being applied to the network, provision of the service to the terminal device is temporarily stopped, and provision of the service to the terminal device is performed after a predetermined time (for example, 90 seconds or more) has elapsed. I'm trying to resume.

[0007] Therefore, for example, during communication with a video conference terminal device, when the power is recovered immediately after a momentary power failure, when the power plug is immediately inserted after the power plug is accidentally unplugged, Even when the power is turned on immediately after the power is turned off, communication cannot be performed because the provision of the ISDN service is not resumed until the predetermined time has elapsed.

It is inconvenient for the user to stop providing the ISDN service for a predetermined time due to the stop of the supply of the power during communication, since this leads to a loss of time. Therefore, for example, in a video conference terminal device, a battery that supplies enough power to continue communication for a sufficient time even in the event of a power failure is provided, or a power switch is provided with a software switch so that the power is not turned off accidentally during communication. Conventionally, it has been considered to prevent the power supply from being stopped during communication by performing control.

[0009]

However, providing a battery for supplying such a sufficient amount of power leads to a significant increase in the cost and size of the video conference terminal device. Further, simply controlling the power switch by software without providing such a battery can prevent the power supply from being stopped due to an erroneous operation of the power switch, but cannot prevent the power supply from being stopped due to a power failure.

As described above, in the conventional video conference terminal device, it is possible to avoid a situation in which the provision of the ISDN service is temporarily stopped due to the stop of the power supply during communication without increasing the cost and the size. Did not.

In the above description, a terminal device for a video conference is taken as an example. However, in order to solve the inconvenience of the user, the terminal device for the other terminal device using the ISDN line is also used.
It is desired to avoid a situation in which provision of the SDN service is suspended. That is, for example, even in a mobile phone, power supply may be stopped during a call due to consumption of a built-in battery or erroneous operation of a power key. Therefore, it is desired to avoid a temporary stop of the service.

In view of the above, the present invention provides a method for temporarily providing an ISDN service to a terminal device when power supply to the terminal device is stopped during communication of the terminal device using an ISDN line. The purpose of the present invention is to make it possible to avoid the situation of suspension without increasing costs and increasing the size.

[0013]

In order to solve this problem, the applicant of the present invention provides a terminal device using an ISDN line with a power supply from a power source during communication, as described in claim 1. Detecting means for detecting that the power supply has been stopped; disconnecting means for normally disconnecting the connection to the ISDN line based on the detection of the stop of power supply by the detecting means;
It is proposed to include a power storage unit that supplies power for a time required to disconnect the connection with the SDN line.

In this ISDN terminal device, when the supply of power from the power supply is stopped during communication using the ISDN line, this is detected by the detecting means. Then, based on the detection result, the connection with the ISDN line is normally disconnected by the disconnection unit while the power is supplied from the power storage unit.

As described above, even when the power supply from the power supply is stopped during communication, the connection with the ISDN line is normally disconnected, so that a situation in which the provision of the ISDN service is temporarily stopped is avoided. Become like Further, the power storage means only needs to supply power for a short time required to disconnect the connection with the ISDN line, and therefore, it is sufficient to provide the power storage means in a video conference terminal device conventionally. Unlike a battery that supplies enough power to continue communication over time, there is no increase in cost or size.

In an ISDN terminal device such as a video conference terminal device having a primary group speed interface and using a commercial AC power supply, for example, a second aspect of the present invention is described.
And a means for monitoring the level of the AC voltage from the power supply at a predetermined fraction of the period of the AC voltage. When,
It is preferable to include means for detecting a stop of power supply based on a result of monitoring the binarized value within the predetermined number of times.

As a result, the stoppage of the power supply from the power supply is detected within one cycle of the AC voltage from the power supply (for example, within 20 milliseconds for a commercial power supply having a frequency of 50 Hz). Therefore, after the supply of power from the power supply is stopped during communication, the connection with the ISDN line is quickly disconnected, and the power required by the power storage means is reduced accordingly. Therefore, an increase in cost and an increase in size can be further prevented.

It is preferable that the power storage means also serves as a capacitor provided in a power supply circuit in the ISDN terminal device, for example, as described in claim 3. As a result, it is not necessary to provide a new component as the power storage means, so that an increase in cost and an increase in size due to the presence of the power storage means can be completely prevented.

Next, as a method for disconnecting the ISDN terminal device from the ISDN line, the present applicant proposes a method for disconnecting at least the ISDN line after the power supply from the power supply is stopped. A first step of supplying power for a time required to disconnect the connection from the power storage means, a second step of detecting that supply of power from the power supply is stopped during communication, and And performing the third step of normally disconnecting the connection with the ISDN line based on the detection of the stop of the power supply.

In this method of disconnecting the connection from the ISDN line, after the supply of power from the power supply is stopped, at least the power required for disconnecting the connection from the ISDN line is supplied from the power storage means, and the communication is performed. During which the supply of power from the power supply was stopped, and based on this detection result,
The connection with the ISDN line is normally disconnected while the power is supplied from the power storage means.

As described above, even when the power supply from the power supply is stopped during communication, the connection with the ISDN line is normally cut off, so that the provision of the ISDN service is temporarily stopped. Will be avoided. Further, the power storage means only needs to supply power for a short time required to disconnect the connection with the ISDN line, and therefore, it is sufficient to provide the power storage means in a video conference terminal device conventionally. Unlike a battery that supplies enough power to continue communication over time, there is no increase in cost or size.

In an ISDN terminal device such as a video conference terminal device having a primary group speed interface and using a commercial AC power supply, for example, claim 5
In the second step, the level of the AC voltage from the power supply is binarized in the second step, and the binarized value is monitored at intervals of a predetermined fraction of the cycle of the AC voltage. It is preferable to detect the stop of the power supply based on the monitoring result of the binarized value within the number of times.

As a result, the stop of the supply of power from the power supply is detected within one cycle of the AC voltage from the power supply. Therefore, after the power supply from the power supply is stopped during the communication, the process immediately proceeds to the third step to perform the IS
Since the connection with the DN line can be cut off, and the electric power required to be supplied by the electric storage means is reduced by that much, an increase in cost and an increase in size can be prevented more effectively.

The power storage means for supplying electric power in the first step is, for example, as described in claim 6 as follows.
It is preferable to use a capacitor provided in a power supply circuit in the ISDN terminal device. As a result, it is not necessary to provide a new component as the power storage means, so that an increase in cost and an increase in size due to the presence of the power storage means can be completely prevented.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example in which the present invention is applied to a video conference terminal device will be described. FIG.
1 shows a general configuration example of a video conference system using a DN line. FIG. 6A shows a multi-point conference control device (center) 21 that integrates the operation control functions of the video conference as a center, and the video conference terminal devices 22 at a plurality of locations are connected to the I-mode.
This is an example of connecting with SDN. FIG. 6B is an example in which the video conference terminal devices 22 at a plurality of locations are connected without providing a center so that the video conference terminal device 22 at any location can control the operation of the video conference.

FIG. 7 shows a general configuration example of each of the video conference terminal devices 22 of FIG. In the video conference terminal device 22, the video codec 2
4 and the audio data picked up by the microphone 25 and encoded by the audio codec 26 are multiplexed by the multiplexing / demultiplexing unit 27 and
It is transmitted via the DN line interface 28.

The ISDN line interface 28
Of the data received via the multiplexing / demultiplexing unit 27, the moving image data is decoded by the moving image codec 24 and displayed on the display 29, and the audio data is decoded by the audio codec 26 and output from the speaker 30. Is output. Also, although not shown in FIG.
Some devices are provided with a device for transmission / reception and display, a facsimile, and a printer.

The video conference terminal uses a commercial power supply, and its AC voltage is converted into a DC voltage by the power supply circuit 31 and supplied to each unit in the video conference terminal 22. Various operation switches are arranged on the operation unit 32. Among them, the power of the video conference terminal device is turned on / off.
A power switch to turn off is also included. The control unit 33 controls the operation of each unit of the video conference terminal device 22,
Transmission and reception of various control signals via the ISDN line interface 28 are performed.

Next, a description will be given of a characteristic portion of the video conference terminal device to which the present invention is applied. As shown in FIG. 1, the video conference terminal device to which the present invention is applied is provided with a power-off detection unit 1 and a power storage unit 2. Is input.

The power-off detecting section 1 detects the stop of the supply of electric power from the commercial power supply, and outputs an output signal between the microcomputer including the CPU 4, the ROM 5, and the RAM 6 and its peripheral devices. Is input to the CPU 4 via an input / output control unit (I / O) 3 for controlling transmission and reception of the signal.

When the supply of power from the commercial power supply is stopped during communication based on an input signal from the power-off detecting section 1, the CPU 4 controls the input / output of a control signal for disconnecting from the ISDN line. This is transmitted through the section 3 and the ISDN line interface 7 (corresponding to the ISDN line interface 28 in FIG. 7) to execute processing for normally disconnecting the connection with the ISDN line. In ROM5,
A program for this connection disconnection processing is stored, and is used as a work area in the RAM 76 during the execution of this processing. These CPU 4, ROM 5, and R
As the AM 6, for example, the video conference terminal device 2 shown in FIG.
In the second embodiment, the one provided in the control unit 33 may be used.

When the supply of power from the commercial power supply is stopped, power storage unit 2 supplies power for the time required to normally disconnect the connection to the ISDN line to each unit in the video conference terminal device. Things.

FIG. 2 shows an example of the configuration of the power-off detector 1 of FIG. In the power-off detecting unit 1, the AC voltage of 100 V is reduced to 5 V by the transformer 11. One end of the secondary side of the transformer 11 is grounded, and the other end is connected to one end of the capacitor 12. The other end of the capacitor 12 is connected to the inverter 13, and the output signal of the inverter 13 is fed back to the inverter 13 via the resistor 14 and is input to the Schmitt trigger circuit 15.

The 5 V AC voltage on the secondary side of the transformer 11 is shaped into a square wave having a duty ratio of 50% and an amplitude of 5 V by the capacitor 12, the inverter 13, the resistor 14, and the Schmitt trigger circuit 15, and this waveform is formed. A square wave signal is output from the power interruption detection unit 1. The input / output control unit 3 converts the level 0 V and 5 V of the square wave signal into binary signals of “0” and “1” and inputs the binary signal to the CPU 4.

FIG. 3 shows an example of the configuration of power storage unit 2 in FIG. A switching power supply circuit is used as a power supply circuit (corresponding to the power supply circuit 31 in FIG. 7) for converting an AC voltage from a commercial power supply into a DC voltage in the video conference terminal device to which the present invention is applied. 1 of this switching power supply circuit
On the next side, a bridge rectifier 16 for rectifying an AC voltage of 100 V from a commercial power supply, and a capacitor 17 for storing a DC voltage of about 140 V rectified by the bridge rectifier 16.
And a constant voltage circuit 18 for stepping down and stabilizing the voltage stored in the capacitor 17 to 5 V.

As the power storage unit 2, the capacitor 17 of the switching power supply circuit is also used. When the supply of electric power from the commercial power supply is stopped from this capacitor 17, it is possible to supply electric power to each unit in the video conference terminal device for about 50 to 100 milliseconds.

FIG. 4 is a flowchart showing an example of processing executed by the CPU 4 of FIG. 1 during communication. First, a timer of 1/3 f seconds (for example, about 6.7 milliseconds in the case of a commercial power supply having a frequency of 50 Hz) with respect to the frequency f of the AC voltage from the commercial power supply is prepared, and the timer is initialized. A monitoring flag for monitoring the output signal of the disconnection detecting unit 1 is prepared, and the value of the monitoring flag is set to “0” or “1”.
Initialize to one (Step S1).

Subsequently, the value of the loop counter is set to 3 (step S2), and the process waits until 1 / 3f second elapses (step S3). Then, when 1 / 3f seconds elapse,
It is determined whether or not the current value of the signal input from the power interruption detection unit 1 via the input / output control unit 3 matches the value of the monitoring flag (step S4).

If they do not match, the value of the monitoring flag is set to the current value of this input signal (step S5), and the steps from step S2 are repeated. On the other hand, if they match, the value of the loop counter is decremented by 1 (step S6), and it is determined whether or not the value of the loop counter has become 0 (that is, the value of this input signal every 1 / 3f second is continuous three times). Is determined to be the same) (step S7).

As exemplified in FIG. 5A, the power-off detecting section 1
Is a signal that repeats "0" and "1" every 1/2 f of the cycle when the AC voltage is supplied from the commercial power supply, so the value every 1/3 f second is continuous three times. And will not be identical. Therefore, at this time,
The value of the loop counter never becomes zero. Therefore, if the value of the loop counter is not 0, since the AC voltage is supplied from the commercial power supply, the process returns from the step S7 to the step S3, and repeats the steps from the step S3.

On the other hand, as shown in FIG. 5B, when the supply of the AC voltage from the commercial power supply is stopped, the input signal from the power-off detection unit 1 becomes a signal of value “0”.
The value every 1 / 3f second becomes the same three times in a row. Therefore, at this time, the value of the loop counter becomes 0.

If the value of the loop counter does not become 0, the supply of the AC voltage from the commercial power supply is stopped, and the power supply unit 2 (the capacitor 17 in FIG. 3) of FIG. Since the power is supplied to the respective parts in the system, the process proceeds from step S7 to step S8, where a control signal for disconnecting the connection with the ISDN line is transmitted via the input / output control unit 3 and the ISDN line interface 7. Transmit and disconnect the connection with the ISDN line normally. Then, the process ends.

As described above, in this video conference terminal device, during communication, 1 / 3f of the input signal from the power-off detection unit 1 is output.
When the value per second becomes the same three times in a row (ie,
After the supply of power from the commercial power supply is stopped, the connection with the ISDN line is normally disconnected within one cycle of the AC voltage from the commercial power supply. One cycle of this AC voltage is, for example, 20 milliseconds with a commercial power supply having a frequency of 50 Hertz, whereas power is supplied from the power storage unit 2 for about 50 to 100 milliseconds as described above. While power is being supplied, the disconnection from the ISDN line can be completed.

As a result, a power failure, accidental disconnection of the power plug of the video conference terminal device from the outlet,
Even if power supply from the commercial power supply is stopped during communication due to accidentally operating the power switch to turn off the power, the connection to the ISDN line is normally disconnected. The suspension of service provision can be avoided. In addition, since the capacitor 17 originally provided in the switching power supply circuit in the video conference terminal device is also used as the power storage unit 2 without providing new components, the cost increase due to the presence of the power storage unit 2 increases. Enlargement is completely prevented.

In the above example, the input signal from the power-off detecting unit 1 is monitored every 1 / 3f second, and when the value every 1 / 3f second becomes the same three times in succession, the ISDN line The connection with is disconnected. However, the present invention is not limited to this. For example, the input signal is monitored every 1 / 4f second, and when the value every 1 / 4f second becomes the same four times in a row, the connection with the ISDN line is disconnected. This input signal is sent for 1 / n second (n is 2
Monitoring may be performed for each of the above-mentioned arbitrary integers), and the connection with the ISDN line may be cut off based on the monitoring result of the value within n times.

Alternatively, such a power-off detection unit 1
The stop of the supply of power from the power supply may be detected and the connection to the ISDN line may be disconnected by an appropriate method other than periodically monitoring an input signal from the ISDN.

In the above example, the capacitor 17 provided in the switching power supply circuit in the video conference terminal device is also used as the power storage unit 2. However, the present invention is not limited to this. May be provided. Even in such a case, the power storage unit 2 only needs to supply power for a short time required to disconnect the connection to the ISDN line, and therefore, there is no increase in cost and size.

In the above example, the present invention is applied to a video conference terminal device, but the present invention is also applied to other terminal devices (for example, telephones, video telephones, computers, etc.) using an ISDN line. May do it. Further, the present invention is not limited to the above-described example, and it is needless to say that various other configurations can be adopted without departing from the gist of the present invention.

[0049]

As described above, according to the ISDN terminal device of the first aspect of the present invention, when the supply of power from the power supply is stopped during communication, power is supplied from the power storage means. In the meantime, the connection with the ISDN line is normally disconnected. Further, the power storage means only needs to supply power for a short period of time required for disconnecting the connection with the ISDN line, so that there is no increase in cost and size. Therefore, when the power supply to the ISDN terminal device is stopped during communication, it is possible to avoid a situation in which the provision of the ISDN service to the terminal device is temporarily stopped without increasing the cost and the size. can get.

According to the ISDN terminal device of the second aspect, after the supply of power from the power supply is stopped during communication, the connection with the ISDN line is immediately disconnected, and the power storage means Since the amount of power required to be supplied is reduced by that amount, the effect that the cost increase and size increase can be more effectively prevented can be obtained.

Further, according to the ISDN terminal device of the third aspect, it is not necessary to provide a new component as a power storage means, so that an increase in cost and an increase in size due to the presence of the power storage means can be completely prevented. can get.

Next, the IS according to claim 4 of the present invention.
According to the method for disconnecting the connection with the DN line, when the supply of power from the power supply is stopped during communication, the connection with the ISDN line is normally disconnected while the power is supplied from the power storage unit. Like that. The power storage means is ISDN
It suffices to supply power for a short time required to disconnect the connection to the line, so that there is no increase in cost or size. Therefore, when the supply of power to the ISDN terminal device is stopped during communication, the IDN
The effect of being able to avoid a situation in which provision of the SDN service is temporarily suspended without increasing costs or increasing the size is obtained.

Further, according to the method for disconnecting from the ISDN line according to the fifth aspect, after the supply of power from the power supply is stopped during communication, the connection with the ISDN line can be immediately disconnected. In other words, the amount of power required to be supplied to the power storage means is reduced by the corresponding amount, so that an effect that the cost increase and the size increase can be more effectively prevented can be obtained.

Further, according to the method for disconnecting the connection with the ISDN line according to the sixth aspect, it is not necessary to provide a new component as the power storage means, so that the cost increase and the size increase due to the existence of the power storage means are completely eliminated. The effect that it can prevent is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a characteristic portion of a video conference terminal device to which the present invention is applied.

FIG. 2 is a diagram illustrating an example of a configuration of a power-off detection unit 1 of FIG. 1;

FIG. 3 is a diagram illustrating an example of a configuration of a power storage unit 2 in FIG.

FIG. 4 is a flowchart illustrating an example of a process executed by a CPU 4 of FIG. 1;

FIG. 5 is a diagram illustrating an example of a signal input to the CPU 4 from the power-off detection unit 1 in FIG.

FIG. 6 is a diagram illustrating a general configuration example of a video conference system.

FIG. 7

It is a diagram showing a general configuration example of a video conference terminal device.

[Explanation of symbols]

1 power cut-off detection unit, 2 power storage unit, 3 input / output control unit, 4 CPU, 5 ROM, 6 RAM, 7,28 ISDN line interface, 11 transformer, 12,17 capacitor, 13 inverter, 14 resistor, 15 Schmitt trigger Circuit, 16 bridge rectifier, 18 constant voltage circuit,
21 multipoint conference control device, 22 video conference terminal device, 23 camera, 24 video codec,
25 microphones, 26 audio codecs, 27
Multiplexing / demultiplexing unit, 29 display, 30 speaker, 31 power supply circuit, 32 operation unit, 33 control unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference)

Claims (6)

[Claims] 1. A terminal device using an ISDN line, comprising: detecting means for detecting that power supply from a power supply has been stopped during communication; and detecting detection of the stop of the power supply by the detecting means. An ISDN terminal device comprising: a disconnecting unit that normally disconnects a connection with an ISDN line; and a power storage unit that supplies at least power for a time required to disconnect the connection with the ISDN line. 2. The ISDN terminal device according to claim 1, wherein the power supply is an AC power supply, and the detecting unit controls the level of the AC voltage from the power supply to two.
Means for digitizing, means for monitoring the binarized value at intervals of a predetermined number of times of the cycle of the AC voltage, and monitoring results of the binarized value over the predetermined number of times or less. And a means for detecting a stop of the supply of the electric power based on the ISDN terminal. 3. The ISDN terminal device according to claim 1, wherein a capacitor provided in a power supply circuit in the ISDN terminal device is also used as the power storage means. 4. A method for disconnecting a connection to an ISDN line in a terminal device using the ISDN line, the method comprising:
A first step of supplying power for a time required to disconnect the connection with the DN line from the power storage means, a second step of detecting that supply of power from the power supply is stopped during communication, Based on the detection of the stop of the power supply from the power supply,
And a third step of normally disconnecting the connection with the DN line.
How to disconnect from N line. 5. The method according to claim 4, wherein the power supply is an AC power supply, and in the second step, the level of the AC voltage from the power supply is binary. And monitors the binarized value at intervals of a predetermined number of times of the cycle of the AC voltage. Based on the monitoring result of the binarized value within the predetermined number of times, the binarized value of the electric power is monitored. A method for disconnecting connection with an ISDN line in an ISDN terminal device, comprising detecting a stop of supply. 6. The method of disconnecting an ISDN terminal device from an ISDN line according to claim 4 or 5, wherein in the first step, the power storage means is provided in a power supply circuit in the ISDN terminal device. ISD in ISDN terminal device characterized by also using capacitor
How to disconnect from N line.