JP3006087B2 - Line terminal equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line terminal device connected to a telephone line and capable of using a no-ringing communication service.

2. Description of the Related Art In recent years, no-ringing communication services have begun to spread in automatic meter reading of gas, water, and the like. This service has conventionally been provided by installing a line terminal device on a telephone at home. The features of the service include using the idle time of the telephone line, giving priority to the use of the telephone, and receiving a call to the line terminal device without ringing the telephone bell.

FIG. 3 shows a conventional line terminal of this type. The line terminal device detects a potential difference between the connected telephone lines 1,
Issue a no ringing connection start request signal at the time of polarity inversion,
Also, a polarity reversal detection unit 2 that issues a no-ringing connection end request signal when the next polarity is restored, an off-hook control unit 3 that performs impedance control on the telephone line 1, a transmission / reception unit 4 that transmits and receives data, and a polarity reversal detection unit 2 When the no-ringing connection start request signal is received from the telephone line, the off-hook control unit 3 semi-closes the telephone line 1 and drives the transmission / reception unit 4 to detect a no-ringing call signal and thereafter establish a link with the communication partner. Or a main control unit 5 that, upon receiving a no-ringing connection termination request signal from the polarity reversal detection unit 2 even during communication, releases the telephone line 1 by the off-hook control unit 3 and terminates the no-ringing communication. .

Next, FIG. 4 shows a configuration of the polarity inversion detecting section 2, and FIG. 5 shows a time chart for explaining the operation thereof. The point is the potential difference between telephone lines, which normally holds about 48v. Now, when the polarity is reversed or restored, the polarity reversal edge detection circuit 21 detects the change point (for example, when the potential difference between
An H pulse is generated as indicated by the point (at the point where v becomes a point). This captures a change in the potential difference between two points in order to enable connection to a telephone line in either direction. As indicated by the dots, the T flip-flop 22 holds the H level during the period from the rising of the H pulse corresponding to the first polarity inversion to the rising of the H pulse corresponding to the next polarity recovery. That is, the H level is maintained while the polarity of the telephone line is inverted, and the L level is maintained throughout the recovery of the polarity. The rising edge detector 23 outputs an H pulse as a point as a no ringing connection request signal when the point changes from the L level to the H level. The falling edge detector 24 outputs an H pulse as a point as a no ringing connection end request signal when the point changes from the H level to the L level. In the above configuration, the polarity inversion detecting unit 2 issues a no-ringing connection start request signal at the first polarity inversion, and issues a no-ringing connection end request signal at the next polarity recovery.

SUMMARY OF THE INVENTION However, in such a conventional line terminal device, the polar opposite edge detection unit outputs an H pulse in response to the instantaneous interruption and restoration of the line voltage during communication. The communication must be terminated unconditionally.

Further, when two H pulses are output from the polar opposite edge detecting unit due to chattering or the like at the time of polarity inversion or polarity restoration, the next polarity restoration or polarity inversion is regarded as the opposite one. The same applies to noise on telephone lines and noise on internal circuits.

The present invention solves the above-mentioned problems, avoids unconditionally terminating communication when line voltage is momentarily interrupted or restored, and malfunctions by regarding the polarity inversion and polarity restoration of the telephone line as the opposite of each other. The purpose is to provide a line terminal device that does not.

Means for Solving the Problems In order to achieve the above object, a line terminal device of the present invention
A polarity inversion detection unit is provided for issuing a no-ringing connection start request signal both at the time of the first polarity inversion (ie, the odd-numbered inter-line potential difference change point) and the next polarity restoration (ie, the even-numbered inter-line potential difference change point). Things.

In addition, a line disconnection detection unit that issues a no-ringing connection termination request signal when a potential difference between telephone lines has become equal to or less than a predetermined value for a certain period of time is provided.

In addition, a line voltage abnormality detection unit that issues a no-ringing connection termination request signal when the potential difference between the telephone lines becomes equal to or more than a predetermined value for a predetermined time is provided.

In addition, a non-communication state detection unit that issues a no-ringing connection end request signal when the non-communication state with the communication partner via the telephone line has elapsed for a predetermined time or more.

In addition, a power supply disconnection detection unit that issues a no-ringing connection termination request signal when the power supply voltage falls below a predetermined value is provided.

In addition, an off-hook detection unit that issues a no-ringing connection end request signal when an off-hook state of a connected device is detected.

Operation According to the above-described configuration, the present invention starts or continues the no-ringing connection at the time of the first polarity reversal and at the time of the next polarity recovery. In other words, the no-ringing communication is not terminated by the signal output from the pole detection unit. The factors that complete the no-ringing communication are:
(1) When the line disconnection state continues for a certain period of time or more, (2) When the potential difference between lines exceeds a predetermined value for a certain period of time or more, and (3) Non-communication such as disconnection of a carrier signal from a communication partner. (4) when the internal power supply voltage falls below a predetermined value, and (5) when an off-hook state of a connected device such as a telephone is detected.

Therefore, at the time of the first polarity reversal and at the time of the next polarity recovery, the telephone line is once semi-closed and the link establishment standby state is established so that the no-ringing call signal can be detected. Then, since no ringing call signal or carrier signal does not come from the communication partner, the telephone line is opened by the output from the non-communication state detecting unit after a certain period of time has elapsed, so that the no-ringing communication is terminated.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In FIG. 1, blocks having the same functions as those shown in the conventional example of FIG. 3 are given the same reference numerals. As in the conventional example, an off-hook control unit 3 for controlling impedance on the telephone line 1 and a transmitting / receiving unit 4 for transmitting / receiving data.
And a main control unit 5 that controls the connection of the off-hook control unit 3 in response to the no-ringing connection start request signal or the no-ringing connection end request signal, and drives the transmission / reception unit 4. The polarity reversal detector 6 is connected to the telephone line 1,
At the time of the first polarity inversion, a no-ringing connection start request signal is issued both at the time of the first polarity inversion (that is, at the odd-numbered line potential difference change point) and at the time of the next polarity inversion (that is, at the even-numbered line potential difference change point). This configuration is equivalent to the polarity edge detection circuit 21 shown in the conventional example of FIG. FIG. 2 shows a time chart for explaining the operation. The point is the potential difference between telephone lines, which normally holds about 48v. Now, when the polarity is reversed or restored, the polarity reversal edge detection circuit 21 detects the change point (for example, when the potential difference between the lines is 0 V
H pulse is generated as indicated by a point (at a point where the voltage becomes 32v from the above). This H pulse is output as it is as a no ringing connection start request.

Further, when the potential difference between the telephone lines has become equal to or less than a predetermined value for a certain period of time, a line disconnection detection unit 7 that issues a no-ringing connection end request signal of an H pulse. A line voltage abnormality detector 8 that issues a no-ringing connection termination request signal of a pulse, a non-communication state that issues a no-ringing connection termination request signal of an H pulse when a non-communication state with a communication partner via a telephone line has passed for a predetermined time or more. Detecting unit 9, power-down detecting unit 10 that issues an H-pulse no-ringing connection termination request signal when the power supply voltage falls below a predetermined value, and ends the H-pulse no-ringing connection when an off-hook state of the connected device is detected. An off-hook detection unit 11 that issues a request signal is provided. Line disconnection detection unit 7, line voltage abnormality detection unit 8, non-communication state detection unit 9, power supply disconnection detection unit 10, off-hook detection unit 11
Sends an H-pulse no-ringing connection end request signal when each state is detected. All of these are connected by a positive logic OR gate 12, and if at least one or more events occur, the no-ringing connection end request signal Is transmitted to the main control unit 5 to terminate the no-ringing communication.

In the above-described configuration, the function of the polarity reversal detecting unit 6 always starts the no-ringing communication at the point where the potential between the telephone lines changes, so whether the generated change in the potential between the lines is the first polarity reversal or the next polarity restoration. Need not be distinguished. Also, even if the no-ringing connection start request signal is output at the wrong place due to chattering or instantaneous interruption occurring at the time of polarity reversal or polarity recovery, noise on the telephone line, noise on the internal circuit, etc. Once the connection is established, the connection can be disconnected by timeout, and if communication is being performed, the communication state can be ignored and the communication state can be continued.

Regarding the end of the no-ringing communication, it is not determined only by the change point (polarity restoration) of the potential between telephone lines.
In addition to the above-mentioned non-communication state timeout, the process is terminated by any event such as line disconnection, line voltage abnormality, power supply disconnection of the main line terminal device, off-hook detection of a device connected to the main line terminal device, or the like. Regarding the connection control of the no-ringing communication, the operation of the entire system is more reliably realized.

As is clear from the above embodiment, according to the present invention, the start of the no-ringing communication is determined each time the potential between the telephone lines changes, so that the no-ringing communication is inevitably interrupted due to noise, instantaneous interruption, or the like. However, the detection of the first polarity inversion will not be missed without fail next time, and the reliability of the entire system will be improved.

Further, since the complex factor is detected and the condition is determined for the end of the no-ringing communication, the efficiency of the connection control of the no-ringing communication is further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a line terminal apparatus according to one embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of a polarity judgment detecting unit in the apparatus, and FIG. FIG. 4 is a block diagram illustrating a configuration of a polarity determination detection unit in a conventional line terminal device, and FIG. 5 is a time chart illustrating an operation of the polarity determination detection unit in the conventional line terminal device. . 1 ... telephone line, 3 ... off-hook control unit, 4 ... transmission / reception unit, 5 ... main control unit, 6 ... polarity reversal detection unit, 7 ...
Line disconnection detecting section, 8: Line voltage abnormality detecting section, 9: Non-communication state detecting section, 10: Power loss detecting section, 11: Off-hook detecting section, 21: Polarity detecting edge circuit.

Continued on the front page (72) Yoshio Horiike 1006 Kadoma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. ) Inventor Yoshiyuki Oishi 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-56-14762 (JP, A) JP-B-58-8183 (JP, B2) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) H04M 11/00-11/10

Claims (1)

(57) [Claims] 1. A polarity reversal detection unit for detecting the polarity of a telephone line and issuing a no-ringing connection start request signal at the time of reversal and recovery of the polarity, an off-hook control unit for controlling impedance on the telephone line, and data transmission / reception And a line disconnection detecting unit that detects a disconnection state for a predetermined time or more in connection with the telephone line, or an abnormal voltage exceeding a predetermined value between lines of the telephone line for a predetermined time or more. A line voltage abnormality detecting unit for detecting, or a non-communication state detecting unit for detecting that a non-communication state with a communication partner has elapsed for a predetermined time or more, or a power-off detecting unit for detecting that a power supply voltage has dropped below a predetermined value. Or an off-hook detection unit that detects that an off-hook state of another connected device has been detected, and has no ringing connection from the polarity inversion detection unit. The control unit controls the off-hook control unit in response to a request signal to drive the transmission / reception unit, and further includes the line disconnection detecting unit, the line voltage abnormality detecting unit, the non-communication state detecting unit, the power disconnection detecting unit, and the off-hook detecting unit. And a main control unit that receives the detection signal from the control unit as a no-ringing connection end signal, controls the off-hook control unit, and releases the line.