JP3143322B2 - Subscriber line monitoring method and device, and subscriber line test monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a subscriber terminal in an off-hook state, in which a Howrah signal is transmitted via a subscriber line in a power-supplied state. More particularly, the present invention relates to a subscriber line monitoring method and apparatus for detecting a state transition to a subscriber line, and a subscriber line test monitoring apparatus including the subscriber line monitoring apparatus therein.

[0002]

2. Description of the Related Art In recent years, as part of infrastructure development of a communication network using an optical fiber cable, a subscriber interface device has been separately installed in a remote place such as a user building from a switching center and each subscriber terminal has been installed. It is designed to be housed once in a subscriber interface device via a subscriber line (metallic subscriber line) and then housed in a switching center via an optical fiber cable. More specifically, as shown in FIG. 6, each of the subscriber terminals 1 is connected to a subscriber line 3 corresponding to the subscriber terminal 1 via a terminal connection terminal 2 and then connected to the subscriber via a subscriber connection terminal 4. It is temporarily housed in a subscriber interface device 5 including a plurality of subscriber circuits 50 corresponding to the terminals 1 and further exchanged via an optical fiber cable 12 provided commonly to each of the subscriber terminals 1. It is housed in the station building 80.

When each of the subscriber terminals 1 is accommodated in the subscriber interface device 5 as described above, various types of signals are applied to the subscriber line composed of the subscriber line 3 and the subscriber terminal 1. In order to perform testing, measurement, and monitoring on the items, various tests, measurements, and monitoring are performed in a state where the subscriber line 3 is pulled into the subscriber line test monitoring device 51 via a changeover switch in the corresponding subscriber circuit 50. It is to be done. As shown in the drawing, the subscriber line test monitoring device 51 gives a warning to the subscriber in the case of forgetting to return the handset in each of the subscriber terminals 1 (meaning an off-hook state for a long time after the end of the call). Howla signal (audible sound signal)
Signal generation circuit 511 for transmitting a signal, a howla monitoring circuit 510 for detecting a transition of the handset of each subscriber terminal 1 to a return state (on-hook state) during transmission of a howla signal, a howla monitoring circuit 510 When the transition to the on-hook state is monitored, a power supply circuit 513 for supplying DC power to the subscriber line 3 is provided. In addition to the above, the subscriber line test monitoring device 5
In FIG. 1, various test / measurement circuits including a test subscriber circuit 512 are provided. The test subscriber circuit 512 has a line capacity, a ground capacity, a line voltage, and the like. It is provided for supplying DC power to the subscriber line when measurement is performed. The states of these circuits are monitored and controlled by the central control processing unit 514.

As a known document relating to this kind of subscriber line test monitoring technology, for example, Japanese Patent Application Laid-Open No. 63-31276 is known.
0 JP: The (name line monitor circuit), the fourth, as shown in Figure, as an example, A line where a subscriber line by a resistor R ₁ to R _5, at line B, respectively After the potential is divided, the potentials V ₁ and V ₂ after the division are compared by the operational amplifier 11, and the state of the subscriber line is in a loop state from the magnitude relation between these potentials V ₁ and V _2. Or whether it is in the open state. Also, Japanese Patent Application Laid-Open No. 4-154
In Japanese Patent Publication No. 360 (name: ground fault / contact detection circuit), A
The current flowing through each of the A and B lines is detected in the power supply circuit while the current is flowing from the corresponding power supply circuit to each of the line and the B line, and is compared with a reference voltage. .

[0005]

By the way, the number of subscribers accommodated in a subscriber interface device installed remotely from the switching center tends to decrease with the progress of optical fiber transmission lines in the future. On the other hand, on the other hand, the cost and space per subscriber required for the subscriber line test monitoring device are
Is growing in reverse. That is, as a subscriber line test monitoring device for testing, measuring, and monitoring each of the subscriber lines accommodated in the subscriber interface device, in order to economically construct the subscriber interface device, In the future, further miniaturization and cost reduction are demanded. In particular, the Howra monitoring circuit for monitoring and detecting the transition of the subscriber terminal from the off-hook state to the on-hook state and the power supply circuit therefor have a large hardware scale, and a large mounting space is required. The fact is that many costs are required for testing / measuring each subscriber line.

A first object of the present invention is to provide a subscriber terminal in an off-hook state, in which a Howrah signal is transmitted via a subscriber line in a power-supplying state. An object of the present invention is to provide a subscriber line monitoring method capable of easily detecting a state transition to a state. A second object of the present invention is to provide a subscriber terminal in an off-hook state in which a Howrah signal is transmitted via a subscriber line in a power-supplying state and changing the subscriber terminal from an off-hook state to an on-hook state. An object of the present invention is to provide a subscriber line monitoring device capable of easily detecting a state transition. A third object of the present invention is to provide a subscriber line test monitoring apparatus capable of easily detecting a transition of a subscriber terminal to an on-hook state during transmission of a Howrah signal while reducing the mounting space and economically. It is in.

[0007]

SUMMARY OF THE INVENTION The first object of the present invention is basically to provide a subscriber terminal in an off-hook state via a subscriber line in a power supply state and DC isolation from the power supply state. When the Howrah signal is transmitted in the state of being switched on, the load current flowing into the subscriber line is low as a whole.
Te following that the state changes to the current value state, which is achieved by the state transition from the off-hook condition of the subscriber terminal to on-hook condition is detected, more specifically, subscriber line
The inflow load current including the Howla signal component to the
Sampling with a sampling period Ts smaller than the period T _HOW
After pulling, it is larger than the Howla signal period T _HOW
Every predetermined time T, the low current value state within the certain time T
The total number of samplings is the total sum of the high current value state.
Since the number of rings is larger than the number of rings,
A state transition from the hook state to the on-hook state is detected.
It is achieved by being .

The second object is basically to feed a subscriber line and detect a load current flowing into the subscriber line, and transmit a Howrah signal to the subscriber line. A howler signal generating circuit for performing the power supply to the subscriber line by the feeder circuit, a coupling circuit for isolating the howler signal generating circuit in a DC manner, and a howler signal component from the feeder circuit. And an on / off-hook state monitoring circuit for detecting the state transition of the subscriber terminal from the off-hook state to the on-hook state with the state transition of the inflow load current to the low current value state. It is achieved by being composed.

A third object of the present invention is to basically supply power to a subscriber line and detect an inflow load to the subscriber line in order to detect at least a state transition of the subscriber terminal from an off-hook state to an on-hook state. A test subscriber circuit as a power supply circuit for detecting a current, a howla signal generating circuit for transmitting a howla signal to the subscriber line, and when power is supplied to the subscriber line by the test subscriber circuit. In addition, a coupling circuit for DC-isolating the Howla signal generation circuit and a detected inflow load current including a Howla signal component from the test subscriber circuit are monitored, and a low current value state of the inflow load current is monitored. And a state transition circuit for detecting a state transition of the subscriber terminal from the off-hook state to the on-hook state with the on / off-hook state monitoring circuit. It is.

[0010]

The DC impedance seen from the power supply side when the Howrah signal is transmitted to the subscriber terminal via the subscriber line in the power supply state while being isolated from the power supply state in a DC manner is: it is when in the on-hook state is infinite, also a few hundred Ω when in the off-hook state, therefore, the size compared to that of the DC load current on-hook state in the off-hook state Kunar. Therefore, the inflow load current including the Howla signal component (AC current component) to the subscriber line is detected on the power supply side,
When the monitoring processing is performed in a predetermined manner, the state transition of the subscriber terminal from the off-hook state to the on-hook state can be easily detected by the state transition of the inflow load current to the low current value state. In particular, at this time, as a power supply circuit for supplying power to the subscriber line, a test subscriber circuit provided as an existing one in the subscriber line test monitoring device is used,
In addition to the function of detecting the inflow load current to the subscriber line, when the detected inflow load current is monitored and processed by the on / off hook state monitoring circuit, an existing in-subscriber line test monitoring device is provided. It is possible to eliminate the need for a Howrah monitoring circuit and a dedicated power supply circuit therefor, and in the subscriber line test monitoring device, the hardware scale is correspondingly reduced, and thus the mounting space is reduced, and The transition of the subscriber terminal to the on-hook state during the transmission of the Howrah signal can be easily detected economically.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A subscriber line monitoring method and apparatus according to the present invention and a subscriber line test monitoring apparatus will be described below with reference to FIGS.
This will be described below. By the way, at present, the monitoring of the subscriber line is performed exclusively in the subscriber line test / monitoring device, so that the subscriber terminal and the subscriber interface device interposed between the subscriber line test / monitoring device are not provided. The illustration of the subscriber line monitoring in the subscriber line test monitoring device after omitting the illustration is as follows. That is, FIG. 1 shows a schematic block configuration of a main part of a subscriber line test monitoring apparatus according to the present invention in relation to a subscriber terminal and a subscriber line. When each of the subscriber terminals 1 is in the state of forgetting to return the handset, the subscriber terminal 1 is switched to the subscriber interface 1 by the howler sound so that the subscriber can put the subscriber terminal 1 in the on-hook state. After being drawn into the subscriber line test monitoring device via the device, as shown in the figure, a test circuit (with a DC load current detecting function) 512 is connected to the subscriber terminal 1 by a coupling circuit 8. , Subscriber line 3
While the DC load current is being supplied via the
The Howler signal is transmitted via the coupling circuit 8 and the subscriber line 3. In this case, the coupling circuit 8, when viewed from the howler signal generating circuit 51 1 side, allowed function as an AC load subscriber terminal 1, also test for the subscriber circuit 512
Functions as an AC-isolated state, but when viewed from the test subscriber circuit 512, the subscriber terminal 1 functions as a DC load, and the Howra signal generation circuit 511 operates as a DC load. It functions to keep it in an isolation state. In other words, in the subscriber line test monitoring apparatus according to the present invention, the dedicated howler monitoring circuit (510) and the dedicated power supply circuit (513) which are conventionally provided are not required, and are replaced with these. The existing test subscriber circuit 512 provided for measuring line capacitance, line-to-ground capacitance, line voltage and the like is used. The test subscriber circuit 512 is available because the subscriber terminal 1 is connected to the subscriber interface device 5 by the remote installation of the subscriber interface device 5 from the switching center 80. This is because the line length of the line 3 is accommodated, and the transmission signal level of the Howrah signal can be reduced by the shortening of the line length of the subscriber line 3. The test subscriber circuit 512 also detects a DC load current including a Howla signal component (the DC load current is actually detected as being converted into a voltage), but the detected DC load current is turned on. The state transition when the subscriber terminal 1 is switched from the off-hook state to the on-hook state is detected by the predetermined monitoring processing performed by the / off-hook state monitoring circuit 10. Under the control of the control processor 514, the transmission of the Howler signal from the Howler signal generation circuit 511 to the subscriber line 3 is stopped.

The outline of the subscriber line test monitoring apparatus according to the present invention has been described above. Next, monitoring processing in the on / off hook state monitoring circuit 10 will be described. As described above, in the test subscriber circuit 512, the DC load current on the subscriber line 3 during the transmission of the Howrah signal is detected.
Then, from the DC load current on which the Howla signal component is superimposed from the test subscriber circuit 512, focusing on only the DC current component, it is determined whether the subscriber terminal 1 is currently in the off-hook state or the on-hook state. Is to be detected. FIG. 2 shows the on / off hook state monitoring circuit 10.
Although the schematic configuration in one example is shown, the configuration and operation will be described below with reference to the operation example shown in FIG.

That is, the on / off hook state monitoring circuit 10
Then, the DC load current 90 on which the Howla signal component is superimposed from the test subscriber circuit 512 is first continuously sampled by the sampling unit 100 under the condition shown as the following equation 1. I have.

[0014]

(Equation 1)

In the sampling section 100, the DC load current 90 is continuously sampled with a period Ts sufficiently smaller than the Howla signal period T _HOW , and the sampling result for the DC load current 90 is counted by the counting section 101 in the next stage. And is counted for each high / low current value state. In this case, the counting unit 101 uses the reset signal Reset (−) from the outside to generate the period T (T = 10 in this example).
Ts), it is reset
The counting section 101 obtains the total number of samplings for each high / low current value state within the fixed time T at every fixed time T sufficiently larger than the Howla signal period T _HOW . The on / off hook state determination unit 102 compares and determines the total number of samplings in the high current value state and the total number of samplings in the low current value state at regular time intervals T based on the total number of sampling times. The on / off hook state is detected, and the detection result 110 is to be notified to the central control processing unit 514.

The counting operation in the counting section 101 will be described in more detail. The high current value state (corresponding to the off-hook state or the Howra signal component) and the low current value state (corresponding to the on-hook state) during the counting valid period I are described. Assuming that the total number of times of sampling is N and n, respectively, N and n are represented by Equation 2 below.

[0017]

(Equation 2)

Similarly, the counting valid period II is shown as Expression 3.

[0019]

(Equation 3)

In this manner, the total number of samplings N, n counted in each cycle T is turned on / off at the end of the cycle.
Although the comparison is made by the off-hook state determination unit 102, according to the example shown in FIG.
While it is determined that the vehicle is in the off-hook state from the comparison result of N> n, in the counting valid period II, it can be determined that the vehicle is in the on-hook state from the comparison result of N <n.

FIG. 4 shows a schematic configuration of another example of the on / off hook state monitoring circuit 10. In this case, the DC load current 90 on which the Howla signal component is superimposed from the test subscriber circuit 512 is first turned on by the low-pass filter 103 in the on / off hook state monitoring circuit 10 so that the Howla signal component as an AC current component is obtained. Is to be removed. Obviously, in order to remove the Howler signal component, the cutoff frequency fc in the low-pass filter 103 must satisfy the condition expressed by the following Expression 4 with respect to the Howler signal frequency f _HOW .

[0022]

(Equation 4)

The low-pass filter 103 can remove a frequency component higher than the Howrah signal frequency f _HOW from the DC load current 90. The DC load current 90 from which the Howla signal component has been removed is then compared with a preset threshold value by an on / off hook state determination unit (configured as a comparator, as described later) 104. By this, whether the vehicle is in the off-hook state or the on-hook state is detected. FIG. 5 shows a specific configuration example of the on / off hook state monitoring circuit 104. In this case, the low-pass filter 103 includes a resistor R and a capacitor C. The circuit 104 is configured as a comparator 105. Incidentally, when the low-pass filter 103 is composed of the resistor R and the capacitor C, the above-described Equation 4 can be modified as the following Equation 5.

[0024]

(Equation 5)

From this relational expression, it is sufficient that the range of the time constant CR is easily determined and the values of the resistor R and the capacitor C are determined within the range. Now, the DC load current 90 after the removal of the Howler signal component, that is, the output Vo of the low-pass filter 103 is equal to the set threshold value Vref and the comparator 1.
05, and when the comparison result is Vo> Vref, the detection result 110 indicating the off-hook state is obtained.
If the comparison result is Vo <Vref, the detection result 110 indicating that the vehicle is in the on-hook state is obtained, and the central control processing device 514 is notified.

[0026]

As described above, according to the third aspect ,
In a state where a Howrah signal is transmitted to a subscriber terminal in an off-hook state via a subscriber line in a power supply state,
A subscriber line monitoring method capable of easily detecting a state transition of the subscriber terminal from an off-hook state to an on-hook state is provided. A subscriber line monitoring device capable of easily detecting a state transition of the subscriber terminal from an off-hook state to an on-hook state while a Howrah signal is being transmitted via the subscriber line in a power supply state, In the case of the items 2, 5, and 7 , a subscriber line test monitor capable of easily detecting the transition of the subscriber terminal to the on-hook state during the transmission of the Howrah signal with a small mounting space. Devices are obtained respectively.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic block configuration of a main part of a subscriber line test monitoring apparatus according to the present invention in relation to a subscriber terminal and a subscriber line;

FIG. 2 is a diagram showing a schematic configuration of an example of an on / off hook state monitoring circuit according to the present invention;

FIG. 3 is a diagram showing an example of the operation of the on / off hook state monitoring circuit;

FIG. 4 is a diagram showing a schematic configuration of another example of the on / off hook state monitoring circuit according to the present invention;

FIG. 5 is a diagram illustrating a specific configuration example of an on / off hook state monitoring circuit in another example;

FIG. 6 is a diagram showing a block configuration of a subscriber line test monitoring apparatus according to the related art in relation to a subscriber terminal, a subscriber line, a subscriber interface device, and a switching center.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Subscriber terminal, 3 ... Subscriber line, 8 ... Coupling circuit, 10 ...
On / off hook state monitoring circuit, 100: sampling section, 101: counting section, 102: on / off hook state determining section, 103: low-pass filter, 104: on / off hook state determining section, 105: comparator, 511: howler signal Generating circuit, 512 ... Testing subscriber circuit, 514
... Central control processor

──────────────────────────────────────────────────続 き Continuing from the front page (72) Tatsuhiro Fukunari 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within the Information and Communication Division, Hitachi, Ltd. (72) Junji Takayama 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo No. Nippon Telegraph and Telephone Corporation (72) Inventor Satoshi Asami 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-53-20809 (JP, A) JP-A Sho 53-136415 (JP, A) JP-A-58-5071 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04M 3/30 H04M 19/02

Claims (7)

(57) [Claims] 1. A method in which a subscriber terminal in an off-hook state is subscribed to in a state where a Howrah signal is transmitted in a DC-isolated state from the power supply state via a subscriber line in a power supply state. A subscriber line monitoring device for detecting a state transition of a subscriber terminal from an off-hook state to an on-hook state, the power supply circuit supplying power to a subscriber line and detecting a load current flowing into the subscriber line A howler signal generation circuit for transmitting a howler signal to the subscriber line, and a coupling circuit for direct current isolation of the howler signal generation circuit when the power supply circuit supplies power to the subscriber line. And monitor the detected inflow load current including the Howla signal component from the power supply circuit, and change the state of the inflow load current to the low current value state from the off-hook state to the on-hook state of the subscriber terminal. And an on / off hook state monitoring circuit for detecting a state transition to a state. 2. A subscriber line test / monitoring device for performing various tests and monitoring on a subscriber line corresponding to a subscriber terminal selectively drawn into the device, wherein at least the subscriber terminal is off-hook. A test subscriber circuit as a power supply circuit for supplying power to a subscriber line and detecting a load current flowing into the subscriber line to detect a state transition from a state to an on-hook state; and A howler signal generation circuit for transmitting a howler signal to the power supply, a coupling circuit for direct current isolation of the howler signal generation circuit when the test subscriber circuit supplies power to a subscriber line, The detected inflow load current including the Howla signal component from the test subscriber circuit is monitored, and the state of the subscriber terminal is changed from the off-hook state to the on-hook state by the state transition of the inflow load current to the low current value state. A subscriber line test monitoring device internally including an on / off hook state monitoring circuit for detecting a state transition. 3. A method in which a subscriber terminal in an off-hook state is subscribed to in a state where a Howra signal is transmitted in a DC-isolated state from the power supply state via a subscriber line in a power supply state. A subscriber line monitoring method for detecting a state transition of a subscriber terminal from an off-hook state to an on-hook state, wherein the inflow load current including a Howla signal component to the subscriber line is reduced by a sampling period smaller than the Howla signal period T _HOW. After sampling with Ts, the total number of samplings pertaining to the low current value state within the predetermined time T is greater than the total number of samplings pertaining to the high current value state for each fixed time T greater than the Howrah signal period T _HOW. A line transition from an off-hook state to an on-hook state of a subscriber terminal when the subscriber line is large. 4. A method in which a subscriber terminal in an off-hook state is subscribed to in a state where a Howra signal is transmitted in a DC-isolated state from the power supply state via a subscriber line in a power supply state. A subscriber line monitoring device for detecting a state transition of a subscriber terminal from an off-hook state to an on-hook state, the power supply circuit supplying power to a subscriber line and detecting a load current flowing into the subscriber line A howler signal generation circuit for transmitting a howler signal to the subscriber line, and a coupling circuit for direct current isolation of the howler signal generation circuit when the power supply circuit supplies power to the subscriber line. And sampling the detected inflow load current including the Howla signal component from the power supply circuit with a sampling cycle Ts smaller than the Howla signal cycle T _HOW .
For each fixed time T greater than the Howrah signal period T _HOW , the total number of samplings in the low current value state within the fixed time T is greater than the total number of samplings in the high current value state. On / off for detecting the state transition of the subscriber terminal from the off-hook state to the on-hook state
An off-hook state monitoring circuit; 5. A subscriber line test / monitoring device for performing various tests and monitoring on a subscriber line corresponding to a subscriber terminal selectively drawn into the device, wherein at least the subscriber terminal is off-hook. A test subscriber circuit as a power supply circuit for supplying power to a subscriber line and detecting a load current flowing into the subscriber line to detect a state transition from a state to an on-hook state; and A howler signal generation circuit for transmitting a howler signal to the power supply, a coupling circuit for direct current isolation of the howler signal generation circuit when the test subscriber circuit supplies power to a subscriber line, after having sampled with a small sampling period Ts than howler signal period T _HOW detection inflow load current including a howler signal components from the test for the subscriber circuit, and larger than the howler signal period T _HOW At every predetermined time T, the total number of samplings in the low current value state within the predetermined time T is larger than the total number of samplings in the high current value state. A subscriber line test monitoring device internally including an on / off hook state monitoring circuit for detecting a state transition to a state. 6. A method in which a subscriber terminal in an off-hook state is subscribed to in a state where a Howrah signal is transmitted in a DC-isolated state from the power supply state via a subscriber line in a power supply state. A subscriber line monitoring device for detecting a state transition of a subscriber terminal from an off-hook state to an on-hook state, the power supply circuit supplying power to a subscriber line and detecting a load current flowing into the subscriber line A howler signal generation circuit for transmitting a howler signal to the subscriber line, and a coupling circuit for direct current isolation of the howler signal generation circuit when the power supply circuit supplies power to the subscriber line. And comparing the detected inflow load current from the power supply circuit with a constant threshold value with the Howla signal component included in the inflow load current removed, and comparing the inflow load current with the A subscriber line monitoring device comprising: an on / off hook state monitoring circuit for detecting a state transition of the subscriber terminal from an off-hook state to an on-hook state. 7. A subscriber line test / monitoring device for performing various tests and monitoring on a subscriber line corresponding to a subscriber terminal selectively drawn into the device, wherein at least the subscriber terminal is off-hook. A test subscriber circuit as a power supply circuit for supplying power to a subscriber line and detecting a load current flowing into the subscriber line to detect a state transition from a state to an on-hook state; and A howler signal generation circuit for transmitting a howler signal to the power supply, a coupling circuit for direct current isolation of the howler signal generation circuit when the test subscriber circuit supplies power to a subscriber line, The inflow load current detected from the test subscriber circuit is compared with a constant threshold value in a state where the Howla signal component included in the inflow load current is removed. There is And an on / off-hook state monitoring circuit for detecting a state transition of the subscriber terminal from the off-hook state to the on-hook state.