JP2940180B2 - Line terminal equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-ringing line terminal device which is connected to a telephone line, detects data polarity inversion of the telephone line, controls the impedance to a half-closed state, and performs data communication.

[0002]

2. Description of the Related Art A conventional line terminal of this type is connected to a telephone line 1 as shown in FIG. 6, and detects a polarity inversion of a telephone line 1 and a no-ringing call signal. NRS signal detecting section 3, ANS signal transmitting section 4 for transmitting a signal responding to the no ringing call signal, and transmitting / receiving section 5 for transmitting / receiving data to / from a communication partner.
An impedance control unit 6 for switching the DC impedance of the telephone line 1 between open, semi-closed, and closed;
An off-hook detection unit 7 for detecting off-hook of another device 9 connected to a subsequent stage of a communication device such as a telephone, and a main control unit 8 for controlling all the components described above. In the main control unit 8, when the polarity inversion of the telephone line 1 is detected by the polarity inversion detection unit 2, the impedance control unit 6 switches the DC impedance of the telephone line 1 from open (for example, ∞Ω) to half-closed (for example, 10 kΩ). Waits for a no-ringing call signal appearing on the telephone line. When the no ringing call signal expected by the NRS signal detection unit 3 can be normally received, an ANS signal responding to the no ringing call signal is transmitted from the ANS signal transmission unit 4 to the telephone line 1, and thereafter the next polarity is output. No-ringing communication is performed using the transmission / reception unit 5 until inversion is detected.
On the other hand, if the received no-ringing call signal is not an expected signal, or if the no-ringing call signal has not been received for a certain period of time after the detection of polarity inversion, ANS
Without sending a signal, the impedance control unit 6 returns the DC impedance of the telephone line 1 from half-closed to open to terminate the no-ringing communication. If the polarity inversion of the telephone line 1 is detected again by the polarity inversion detection unit 2 during the no-ringing communication using the transmission / reception unit 5, the impedance control unit 6 returns the DC impedance of the telephone line 1 from half-closed to open, and the no-ringing communication. To end. Similarly, also when the off-hook detection signal is received from the off-hook detection unit 7 during the no-ringing communication, the impedance control unit 6 returns the DC impedance of the telephone line 1 from half-closed to open to terminate the no-ringing communication. When a call is transmitted from the main line terminal device, the impedance control unit 6 closes the DC impedance of the telephone line 1 from open (for example, ∞Ω) to close (for example, 300 Ω).
To start the dialing operation. That is, an AA (automatic transmission / reception) type NC corresponding to a no ringing line
It has a U function. Here, it is assumed that the polarity inversion detecting unit 2, the NRS signal detecting unit 3, the ANS signal transmitting unit 4, the transmitting / receiving unit 5, the impedance control unit 6, and the main control unit 8 together constitute a general no-ringing network control unit. Can be considered.

The off-hook detection unit 7 measures a current flowing to another device 9 connected to a subsequent stage of a communication device such as a telephone, and if the current is equal to or more than a predetermined value, outputs an off-hook detection signal of the other device 9 to the main control unit. 8, which indicates that the other device 9 itself controlled the closing of the DC impedance.

[0004]

However, in the above configuration, since the off-hook detecting section only detects the off-hook state (ie, closed) of the other device 9 connected to the subsequent stage, the half-closed state is detected. It is not possible.
Also, as shown in FIG.
When the other device 9 is connected in parallel with the main line terminal device, the closed or semi-closed state of the other device 9 cannot be detected. Further, there is a problem that an abnormal state such as disconnection or short circuit of a telephone line cannot be detected.

The present invention solves such a conventional problem. By measuring the voltage between telephone lines, the impedance of another device connected to the same telephone line or another device connected to the main line terminal device is measured. The purpose is to detect the state and to notify if it is abnormal.

[0006]

In order to solve the above-mentioned problems, a line terminal device according to the present invention comprises a line voltage detecting section for measuring a voltage between telephone lines, and an open or half-closed state by an impedance control section during non-communication. Or a line voltage corresponding to the closing control is stored in advance, and a state detection unit that detects a state on the line from a difference between the stored line voltage and the line voltage measured from the current line voltage detection unit, An abnormality notification unit that receives a signal from the state detection unit and notifies an abnormal state is provided.

[0007]

According to the present invention, the voltage between the telephone lines under open / semi-close / close control by the impedance control unit of the present line terminal device is grasped in advance and connected to the same line. Detect the impedance state of the device.

For example, the power supply voltage supplied from the telephone exchange to the main line terminal is 48 V, and the line resistance of the telephone line 1 is 2
Assume kΩ. If no other device is connected,
When the DC impedance is controlled to be open (for example, ∞Ω), semi-closed (for example, 10 kΩ), and closed (for example, 300 Ω),
The combined resistance of the line resistance and the line terminal equipment is ∞
Ω, 12 kΩ, and 2.3 kΩ. Therefore, the voltages appearing on the telephone line 1 are V (open) = 48 [V] V (half-closed) = (48 / 12k) * 10 k [V] = 40 [V] V (closed) = ( 48 / 2.3k) * 0.3k [V] ≒ 6.3 [V]. Therefore, for example, if the line voltage is measured to be about 40 V instead of 48 V regardless of the open control of this line terminal device, it means that the other device connected to the same telephone line is under half-closed control. . When the line voltage is measured to be about 6.3 V, it means that another device connected on the same line is performing the closing control (ie, off-hook detection). This also applies during no-ringing communication in which the main line terminal device performs half-closing control. If the other device changes from the open control to the semi-closed control (for example, 10 kΩ) during the half-closed control (for example, 10 kΩ), the telephone line voltage V is changed from 40 V to V = 48 / (2 k + 10 k / 2) * 10 k / 2 [V ] ≒
Shift to 34.3 [V]. Similarly, when the other device performs the closing control (for example, 300Ω) during the half-closing control, the voltage between the telephone lines becomes about 6.1 V.
Therefore, the impedance control state of another device connected on the same line is detected. This has exactly the same effect when another device is connected after the main line terminal device or when another device is connected in parallel with the main line terminal device as shown in FIG. 5B.

If the line voltage is 0 V irrespective of the open control of the line terminal device, it is considered that the telephone line is disconnected, disconnected or short-circuited.

[0010]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, elements shown in the block diagram having the same functions as those of the conventional line terminal shown in FIG. The telephone line 1 includes a polarity reversal detection unit 2 for detecting the polarity reversal of the telephone line 1, an NRS signal detection unit 3 for detecting a no ringing call signal, and an ANS signal transmission unit for transmitting a signal responsive to the no ringing call signal. 4 and a transmitting / receiving unit 5 for transmitting / receiving data to / from a communication partner
An impedance control unit 6 for switching the DC impedance of the telephone line 1 between open, semi-closed, and closed;
A line voltage detector 10 for measuring the voltage of the telephone line 1 is connected. The state detection unit 11 is connected to the impedance control unit 6 and the line voltage detection unit 10, and stores in advance the line voltage corresponding to the open, half-close, or close control by the impedance control unit 6 during non-communication,
The impedance state on the telephone line is detected from the difference between the stored line voltage and the line voltage measured by the current line voltage detection unit 10, and a state detection signal is sent to the abnormality notification unit 12.

The main control unit 8 includes a polarity inversion detecting unit 2 and an NRS.
The signal detection unit 3, the ANS signal transmission unit 4, the transmission / reception unit 5, the impedance control unit 6, the line voltage detection unit 10, and the abnormality notification unit 12 are connected. It should be noted that another device 9 such as a telephone is connected to the subsequent stage of the line terminal device.

The abnormality notification unit 12 receives a state detection signal from the state detection unit 11 and determines whether or not the state is abnormal. The abnormality notification unit 12a and an LED display for displaying the abnormality when the state is determined to be abnormal. 12b. When it is determined that the state is an abnormal state, the state detection unit 11 sends a communication prohibition request signal to the main control unit 8.

The control procedure of the no-ringing communication is the same as that shown in the conventional example, and will not be described in detail, but constitutes a similar no-ringing network controller.

First, the operation of the state detection unit 11 will be described with reference to the flowcharts of FIGS. This line terminal device is connected to the telephone line 1, and the initial registration operation is performed in a state where other devices are not connected or under release control. During the initial registration, it must be confirmed that the communication is not performed and the polarity inversion does not occur until the registration is completed (step 20).
1, 202, 214). During non-communication, it is in the open control state, but after closing control in step 203, the line voltage is measured and stored as a closed voltage if 3v ≦ measured voltage ≦ 20v, otherwise it is registered as a range error. Abort. (Steps 204 and 2
05) Similarly, in steps 206 to 208, it is confirmed that the measured voltage during the semi-closed control is 20v ≦ measured voltage ≦ 50v, and in steps 209 to 211, the measured voltage during the open control is 40v ≦ measurement ≦ 60v. I do. Steps 212 and 213
It is also confirmed that the closing voltage <half-closing voltage <open voltage, and three types of voltage information are registered. If the registration has been canceled, the initial registration operation is performed again.

Next, FIG. 3 shows an operation of detecting a line state. In step 301, the current line voltage is measured and this is
If it is larger than (> 0), the process proceeds to step 303. If not, it is regarded as a line disconnection / non-connection or short-circuit failure, and a line disconnection detection signal is transmitted to the main control unit 8 to end the process.
(Step 302) In step 303, it is confirmed whether or not the initial registration shown in FIG. 2 has been completed. Steps 304 and 3 depend on whether the main line terminal is under the closing control, the half closing control or the opening control.
05 branches to any of steps 306 to 308.
If the closing control is being performed, in step 306, the difference V1 between the closing voltage registered in advance and the currently measured voltage is measured.
(= Closing voltage−measured voltage). Step 309-
In 311, if V1 ≦ v11, the process proceeds to step 320, and after determining that the other device 9 is in the open state, transmits an open state detection signal to the main control unit 8 and ends.

If v11 <V1 ≦ v12, the process proceeds to step 319. After determining that the other device 9 is in the half-closed state, the other device 9 transmits a half-closed state detection signal to the main control unit 8, and ends.

If v12 <V1, the process proceeds to step 318, and after determining that the other device 9 is in the closed state, the other device 9 transmits a closed state detection signal to the main control unit 8 and ends. Here, 0 <v11 <v12 <closing voltage. Similarly, in steps 312 to 314, the connection state of the other device 9 is determined during the half-close control of the main line terminal, and in steps 315 to 317, the connection state of the other device 9 is determined during the release control of the main line terminal. I do. Actually, the line voltage is measured not only once but continuously for a plurality of times to confirm that a stable voltage can be obtained. Further, an uncertainty area may be provided between the open state, the semi-closed state, and the closed state.

Next, the abnormality determination operation in the abnormality notification unit 12 will be described with reference to the flowchart of FIG. As described above, there are four types of state detection signals from the state detection unit 11, namely, a disconnection detection state, another device line open state, another device line semi-closed state, and another device line closed state. If the disconnection is detected in step 401, it is immediately regarded as an abnormal state.
Proceed to 10. If the disconnection is not detected, the process proceeds to step 402, and if the line terminal apparatus is under the release control, it is checked whether or not the other device 9 is also in the open state. If the other device 9 is not in the open state in step 403, it is not in an abnormal state,
In this case, the process proceeds to step 411, where only the communication prohibition request signal is transmitted, and the process ends. If this line terminal device is under half-closed control (step 404), it is checked whether or not the other device 9 is in the closed state (step 405). . If the other device 9 is in the semi-closed state, and if the half-closed state is maintained for one second or longer (steps 406 and 407), it is regarded as an abnormal state and the process proceeds to step 410. If the line terminal device is under half-closed control and the other device 9 is under open control, it is regarded as a normal state and the process proceeds to step 408. If the line terminal device is under the closing control, it is regarded as normal without checking the impedance state of the other device 9, and the process proceeds to step 408. In step 408, the LED is turned off, and no communication prohibition request is output (step 409), and the process ends. Step 41
In the case of 0, the abnormal state is notified by blinking the LED, and then a notification prohibition request signal is output (step 411), and the processing is ended.

By this operation, for example, when a plurality of line terminal devices are connected on the same line, and when a specified number or more of line terminal devices are connected, the DC impedance on the line is reduced, so that an abnormal state is caused. It can be determined. If a plurality of line terminal devices are set to respond to the same no-ringing call signal by mistake, the half-closed state will be maintained at the same time, and similarly the impedance on the line will be reduced. become.

Here, one type of LED display of the abnormal state is used, but the type of the abnormality notification may be classified according to the content.

In the above configuration, connection is made on the telephone line and on the telephone line regardless of whether the main line terminal is communicating or not and regardless of the connection form when a plurality of main line terminals are connected to the same telephone line. The abnormal state notification unit 12 immediately terminates the communication of the line terminal device and notifies the abnormal state. is there.

[0023]

As described above, according to the line terminal device of the present invention, the following effects can be obtained.

Since the impedance state on the line is constantly monitored while the system is operating, and in the case of an abnormality, useless communication control can be avoided and an abnormality can be notified, which is very advantageous in maintenance. In particular, when multiple line terminal devices are connected on the same line, are not more than the specified number of line terminal devices connected, or are multiple line terminal devices erroneously holding the half-closed state at the same time? Can be automatically diagnosed, so that the reliability of the entire system can be improved.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a line terminal device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of a state detection unit in the apparatus.

FIG. 3 is a flowchart illustrating the operation of a state detection unit in the apparatus.

FIG. 4 is a flowchart illustrating an abnormality determination operation of an abnormality notification unit in the apparatus.

FIG. 5A is a block diagram illustrating a connection configuration of another device provided at a subsequent stage of the device. FIG. 5B is a block diagram illustrating a connection configuration of another device provided in parallel with the device.

FIG. 6 is a functional block diagram of a conventional line terminal device.

[Explanation of symbols]

 2 polarity reversal detection unit 3 NRS signal detection unit 4 ANS signal transmission unit 5 transmission / reception unit 6 impedance control unit 10 line voltage detection unit 11 state detection unit 12 abnormality notification unit

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiyuki Oishi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A 1-314056 (JP, A) JP-A 1 −256854 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04M 11/00

Claims (3)

(57) [Claims] 1. A no-ringing network controller for switching a line impedance between open, semi-closed, and closed, a line voltage detector for measuring a line voltage, and an open, semi-closed, or closed line during non-communication. A state detection unit that stores the line voltage corresponding to each of the connected lines in advance and detects the impedance state of the line from the difference between the stored line voltage and the line voltage measured from the line voltage detection unit; A line terminal device comprising: an abnormality notification unit that receives a signal from a state detection unit and notifies an abnormal state. 2. The line terminal device according to claim 1, wherein the state detection unit sends a disconnection detection signal to the abnormality notification unit when the line voltage measured from the line voltage detection unit during the release control is equal to or less than a predetermined value. 3. The circuit according to claim 1, wherein when the line voltage measured by the line voltage detecting unit is lower than a previously stored line voltage by a predetermined value or more during the open / semi-closed / closed control.
2. A connection detection signal from another device is sent to an abnormality notification unit.
Line terminal device as described in the above.