JPH01288047A - Terminal state supervising method - Google Patents

Abstract

PURPOSE:To identify not only the state of disable/enable communication but also the state of power on/off of a slave station terminal equipment, line fault such as line interruption and terminal fault state switchingly by identifying the state of the slave station from the master station side depending on the combination of a line current level and the state of a synchronizing signal. CONSTITUTION:A slave station is provided with a function, which enables display of 3 states in a consumed current; consumption of a feeding current from a master station at local power OFF to some degree; consumption of a current over that at local power ON and nearly zero current consumption at lien interruption. On the other hand, the master station is provided with a function identifying the current consumption into 3 states by using two threshold values and also with a synchronization supervisory function, thereby identifying the power ON state, power OFF state, line fault state and terminal fault state of a slave station terminal equipment switchingly. That is, the master station identifies clearly the 4 states of line fault state, terminal fault state, terminal power OFF state and terminal power ON and normal state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to subscriber line circuit devices and terminals used in communication equipment and the like.

BACKGROUND ART FIG. 4 shows a conventional method for monitoring the terminal status (slave station status) of a master station in communication between a master station (network side) and a slave station (user side).

As shown in FIG. 4, the master station always sends a synchronization signal (■) to the slave stations.

The slave station receives the signal and establishes synchronization (
■), loop back the synchronization signal (■).

In this way, the master station can recognize whether it is in a communicable state with the slave station by detecting the synchronization signal returned from the slave station.

In other words, it is possible to identify whether the slave station terminal is normally activated and connected, or whether it is in an Ω failure state such as the power is off or the line is disconnected.

In this way, even with the conventional method described above, the master station can recognize whether the slave terminal is in a communicable state or in a communicable state.

Problems to be Solved by the Invention However, in the conventional terminal status monitoring method described above, since the slave station terminal status is recognized based on the presence or absence of a synchronization signal from the slave station to the master station, only two states can be detected: communicable or not communicable. First, even if communication is not possible, it is impossible to determine whether the local power supply of the terminal is simply turned off or whether there is a failure such as a disconnection of the line or an abnormality in the terminal.

Therefore, although we would like to have a function that switches to the standby system in the event of a line abnormality such as line disconnection or terminal abnormality, when there is no abnormality,
For example, there was a problem in which the switching function was activated due to a local power outage.

The present invention is intended to solve such conventional problems, and is capable of not only identifying whether communication is enabled or disabled, but also identifying the power on/off status of slave terminals, line failures such as line disconnection, and terminal failure status. The purpose of this invention is to provide a terminal status monitoring method that can separate and identify the terminal status.

Means for Solving the Problems In order to achieve the above object, the present invention provides that the slave station consumes a certain amount of power supply current from the master station when the local power is turned off,
The main station has a function that can display three states of current consumption, including a state in which more current is consumed when the local power is on, and a blank state when the line is disconnected. In addition to the function of identifying three states using two thresholds, the master station also has a conventional synchronization monitoring function, allowing the master station to detect the power-on state, power-off state, line abnormality state, and terminal abnormality state of the slave terminal. It is designed so that it can be separated and identified.

Effects The present invention has the following effects due to the above structure.

In other words, the slave station switches the power consumption current depending on the on/off state of the local power supply, and the master station uses two thresholds to distinguish between three states, thereby detecting line abnormalities such as line disconnections with almost zero current consumption. In addition, it is possible to determine whether the slave station terminal is powered off, which is between two thresholds, and the slave terminal is powered on, which consumes more current than the upper threshold. Therefore, by monitoring the synchronization state and determining whether the synchronization is normal or abnormal when the terminal is powered on, it is possible to determine whether the terminal state is normal or abnormal.

That is, on the master station side, four states can be clearly identified: a line fault state, a terminal fault state, a terminal power off state, and a normal state with the terminal power on.

Embodiment FIGS. 1 and 2 show the configuration of an embodiment of the present invention. FIG. 1 shows the power supply circuit and terminal current consumption determination circuit of the master station (network side), and FIG. , is a current consumption switching circuit that switches the power consumption current supplied from the master station depending on the power receiving circuit power on/off state of the slave station (terminal side).

In FIG. 1, 1.2 is a transmitting/receiving transformer, and power is supplied through its center tap.

3 is an overcurrent protection circuit for the power supply current; 4 is a current mirror for detecting the current consumption on the slave station side; this current mirror allows current 1. flow to the opposite side.

5 is a series resistor R1 and R2 through which the current 2 flows, and 7.
8 is a differential amplifier connected to series resistor q.

6 is a voltage/logic conversion section, which converts the input voltage V1 of the differential amplifier 7
and differential amplifier 80 input voltage Vo,
PWSO and PWS, respectively, compared with the hold voltage Vs.
It is output to the I terminal as high and low logic levels.

In Figure 2, 11.12 is a transmitting/receiving transformer on the slave station side, 13.14 is a constant current diode for passing a constant current through the line, and 15 is a relay that operates when the slave station is powered on. A make contact is connected in series with a constant current diode 14.

Next, the operations shown in FIGS. 1 and 2 will be explained.

First, in FIG. 2, when the slave station is powered off, the relay 15 is off and its contacts are open.

Therefore, the current I sent from the master station to the line passes through the transmitting/receiving transformer 11, 12 and the constant current diode 13
=Ia flows.

When the power of the slave station is still on, the relay 15 is on and its contacts are closed, so the above current Ia is applied to the line.
In addition to this, the current Ib flowing through the constant current diode 14 is added, resulting in I-Ia+Ib.

Next, in Figure 1, from the master station to the transmitting/receiving transformer 1.2
, an overcurrent protection circuit 3, and a current mirror 4. A current 1 is supplied to the line via the overcurrent protection circuit 3 and the current mirror 4. The circuit on the opposite side of the current mirror 4 includes 1. (= It flows, which causes resistance R1
A voltage Vl is generated corresponding to the resistance R1+R1, and a voltage ■o is generated corresponding to the resistance R1+R1 (here, vO>vl). This voltage V,
V is converted to a logic level by the voltage/logic converter 6 and output to PWSI and PWSO.

Based on the operations of the master station and slave stations (terminals) described above, a method for identifying four states: line failure, terminal power off, terminal abnormality, and terminal normality is summarized and shown in FIG. In Figure 3, PWSO
, PWSI changes from No 1 to Low, respectively, as IL and In(III>IL>0), and the terminal currents Ia, Ia+Ib and It, , IH satisfy IH<I
It satisfies the relationship a<IL, Ia+Ib>Iu.
,, When IH is set, four states can be identified based on the combination of PWSl, pwso and synchronization state (normal, out of order). In other words, when both Pwsi and pwso are H (high), terminal current I=O, line failure occurs, PWS1=H(
)・a), When PWSO=L (low), terminal current I=L
(low) turns off the terminal power, both PWSI and PWSO are set to low (
low) and out of synchronization, the terminal is abnormal, pws i.

When both pwso and pwso are L (low) and the synchronization is normal, the terminal can be identified as normal.

In this way, according to the above embodiment, the power supply consumption current is determined on the master station side using two threshold values, and the slave station side adjusts the consumption current. By monitoring the synchronization state, line abnormalities, terminal power on/off, and abnormalities can be monitored, and abnormalities can be detected separately from line abnormalities and terminal abnormalities.

Further, according to the above embodiment, when it is desired to have a function of switching to a standby system in the event of a line or terminal abnormality, even if the terminal is powered off, the master station does not recognize it as abnormal due to loss of synchronization. This also has the effect of allowing terminal abnormalities to be monitored even when the terminal is operating with local power supply.

Effects of the Invention In the present invention, as is clear from the above embodiment, the slave station switches the current consumption depending on the power on/off state, and the master station has two thresholds to monitor and identify the current consumption. At the same time, by synchronous monitoring, on the master station side,
It has the advantage of being able to identify four states: a line failure state such as line disconnection, a terminal failure state, a terminal power off state, and a normal state when the terminal power is on.

Furthermore, regarding the switching function in the event of a failure, it is possible to have a function that detects synchronization loss when the terminal is powered off and performs switching only in the event of a failure in the main menu, such as a line abnormality or terminal abnormality, without having to switch. It has the effect of being able to.

[Brief explanation of the drawing]

FIG. 4 is a diagram illustrating a conventional terminal status monitoring method. 1... Master station transmitting transformer, 2... Master station receiving transformer,
3... Overcurrent protection circuit, 4... Current mirror, 5
...Resistors R1, R2, 6...Voltage/logic conversion section, 7
, 8... Differential amplifier, 11... Slave station reception transformer,
12...Slave station transmission transformer, 13. 14... Constant current diode, 15... Relay. Name of agent: Patent attorney Satoshi Nakao and one other person
30th Is>IL>. 4th @ Q3 lo114BKw

Claims (2)

[Claims] (1) A means for changing the line current level supplied from the master station to the slave station (terminal) into two levels depending on whether the slave station is powered on or off, and a line supplied from the master station to the slave station. means for detecting a current level and determining the level into three levels;
A terminal comprising means for detecting a synchronization signal returned from a slave station on the master station side and determining the synchronization state, and identifying the status of the slave station from the master station based on a combination of the line current level and the state of the synchronization signal. Condition monitoring method. (2) Determine the line current level as zero, low, or high; when the line current is zero, there is a line fault; when the line current is low, the terminal power is turned off; when the line current is high and the synchronization is out, the terminal is abnormal;
2. The terminal status monitoring method according to claim 1, wherein the terminal is determined to be normal when the line current is high and the synchronization is normal.