JPH0346446A - Malfunction restoration system for ringing transmission circuit - Google Patents

Abstract

PURPOSE:To suppress useless power consumption due to malfunction of a PNPN switch by providing a malfunction restoration circuit detecting a current flowing to a resistor of a ringing transmission circuit, detecting the malfunction condition of the PNPN switch and storing the result. CONSTITUTION:A ringing transmission circuit 6 supplies a ringing signal source 7 via a PNPN switch 8 to an A line 2 of a subscriber line with a ringing transmission circuit drive signal RNG in the ringing state and supplies a prescribed battery 11 to a B line 3 of the subscriber line via a PNPN switch 9 and a resistor 10. Moreover, a ring trip circuit 12 detects ring trip with loop forming at a subscriber terminal equipment 1 in the ringing state and applies display with a ring trip detection output TRP, and a comparator 13 incorporated in a malfunction restoration circuit 17 detects a current flowing to a resistor 10 with its voltage drop. The malfunction storage circuit 14 discriminates the condition of malfunction of the PNPN switch 9 of the circuit 6 with an AND circuit 15 receiving an output of the comparator 13, the output TRP and the signal RNG, stores the result and it is displayed to a host controller.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a subscriber circuit of a telephone exchange, and particularly relates to a malfunction recovery method for a PNPN switch in a ringing sending circuit.

[Conventional technology]

Conventionally, to prevent malfunction of ringing sending circuits, dv/d
A method using a PNPN switch element with high t tolerance has been considered.

[Problem to be solved by the invention]

The PNPN switch of the conventional ringing sending circuit described above has a high dv/dt tolerance, which specifies the false firing characteristic as a dma/dt tolerance, and has a high dv/dt tolerance to prevent false firing due to sudden voltage changes that occur on the terminal side. Although a PNPN switch is used, sudden voltage changes occurring on the terminal side may exceed the dv/dt tolerance of the PNPN switch, considering electric surges and other dv/dt, so malfunction of the ringing sending circuit is completely prevented. However, once the IFC and PNPN switches are turned on incorrectly, they have a current holding function, which means that the malfunctioning state of the ringing sending circuit is maintained, which hinders the normal operation of the subscriber circuit. there were.

[Means to solve the problem]

The malfunction recovery method of the ringing sending circuit of the present invention is connected to the subscriber terminal by the incoming line and the B line of a two-wire subscriber line, and switching the polarity of the voltage applied to the A line and the B line by a switch circuit. The power supply circuit supplies power to the subscriber terminal, and in the ringing state, the ringing sending circuit supplies a ringing signal to the A line of the above subscriber line via the first PNPN switch, and the second PNPN switch to the B line. In a subscriber circuit of a telephone exchange, a predetermined battery is supplied through a switch and a resistor, and a ring trip circuit detects a ring trip due to loop formation at a subscriber terminal.
A comparator detects the current flowing through the resistor connected between the battery and the second PNPN switch, and an AND circuit detects the condition where the current is not in a shilling trip state and a current flows through the resistor and a voltage drop occurs. A malfunction recovery circuit is provided for detecting and holding a malfunction condition of the second PNPN switch which controls the connection of a predetermined battery to the B line of the subscriber line by detecting and holding the malfunction recovery circuit. By monitoring the malfunction detection display of the circuit, a malfunction of the second PNPN switch that controls the connection of a predetermined battery to the B line of the subscriber line of the Y-ringing transmitting circuit is detected, and the ringing transmitting circuit is activated. This system is designed to perform malfunction recovery control.

[For production]

According to the present invention, a comparator detects the current flowing through the resistance of the ringing sending circuit, and an AND circuit detects and holds the concession operating condition of the PNPN switch of the syringing sending circuit.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

The figure is a block diagram showing one embodiment of the present invention.

In the figure, 1 is the subscriber terminal, 2 is the subscriber line A line, and 3 is the subscriber terminal.
is the B line of the subscriber line, 4 is a switch circuit that switches the polarity of the voltage applied to the subscriber line, 5 is a power supply circuit that supplies talk current to the subscriber terminal 1, and 6 is a switch circuit that switches the polarity of the voltage applied to the subscriber line. Send a ringing signal to line A[2 and send a ringing signal to subscriber line B
This ringing sending circuit 6 supplies a predetermined battery to the line 3, and this ringing sending circuit 6 has a ringing signal source 7 and a PNP.
It is composed of N switches 8, 9, a resistor 10, and a battery 11. 12 is a ring trip circuit that detects a ring trip due to loop formation at the subscriber terminal during the I)7df ringing state, and 13 is a comparator that detects the voltage drop across the resistor 10 connected between the battery 11 and the PNPN switch 90. , 14 is a malfunction judgment holding circuit that determines and holds the malfunction condition of the PNPN switch of the ringing sending circuit 6. This malfunction judgment holding circuit 14 receives the output of the comparator 13, the ring trip detection output TRP, and the ringing sending circuit drive signal. AND circuit 15 with RNG as input
and a latch circuit 1 whose input is the output of the AND circuit 15.
It is composed of 6 parts. Reference numeral 17 denotes a malfunction recovery circuit including a comparator 13 and a malfunction determination holding circuit 14.

The subscriber circuit of the telephone exchange is connected to the subscriber terminal 1 by the A line 2 and B line 3 of the two-wire subscriber line, and is connected to the subscriber terminal 1 by the switch circuit 4! The polarity of the voltage applied to the JI 2 and B line 3 is switched, and the power supply circuit 5 supplies power to the subscriber terminal 1. In the ringing state, the ringing sending circuit 6 connects the PNPN switch 8 to the A line 2 of the subscriber line. A ringing signal is supplied to the B line 3 through a PNPN switch 9 and a resistor 10, and a predetermined battery is supplied to the B line 3.
The Jtub circuit 12 is configured to detect ring trips due to loop formation at subscriber terminals.

In the subscriber circuit of the telephone exchange configured as described above, the present invention detects the current flowing through the resistor 10 connected between the battery 11 and the PN switch 9 using the comparator 13, and converts it into a ring using the AND circuit 15. ) B! of the subscriber line by detecting and holding the condition where the IJ block state is not present and current flows through the resistor 10 and a voltage drop occurs. 3 is equipped with a malfunction recovery circuit 17 that detects and holds a malfunction condition of the PNPN switch 9 that controls the connection of a predetermined battery, and the upper control device monitors the malfunction detection display of the malfunction recovery circuit 1T to generate a ringing sending circuit 6. The system is configured to detect a malfunction of a PNPN switch 9 that controls the connection of a predetermined battery to the B line 3 of the subscriber line, and to perform malfunction recovery control of the ringing sending circuit 6.

Next, the operation of the embodiment shown in this figure will be explained.

1. One end of the switch circuit 4 is connected to the subscriber terminal 1 via the A line 2 and B line 3 of the two-wire subscriber line, and the other end is connected to the power supply circuit 5 to apply voltage to the subscriber line. Switches the voltage polarity. The power supply circuit 5 supplies the communication current to the subscriber terminal 1, and the ringing sending circuit 6 sends a ringing sending circuit drive signal RNG to the A line 2 of the subscriber line via the PNPN switch 8 in the ringing state. Supply signal source T and connect PNPN to subscriber line B line 3.
A predetermined battery 11 is supplied via a switch 9 and a resistor 10. t'fc, the ring trip circuit 12 detects a shilling trip due to the formation of a loop in the subscriber terminal 1 during the ringing state, and displays the ring trip detection output TRP, and the comparator 13 built in the malfunction recovery circuit 17 The current flowing through the resistor 10 is detected based on the voltage drop. The malfunction holding circuit 14 determines and holds the malfunction condition of the PNPN switch 9 of the ringing transmission circuit 6 using an AND circuit 15 which receives the output of the comparator 13, the ring trip detection output TRP, and the ringing transmission circuit drive signal RNG. and display it on the higher-level control device.

Next, when there is no ringing state, the ringing signal and the prescribed battery are not supplied to the subscriber line from the ringing sending circuit 6, the PNPN switch 9 is turned off, and current flows through the resistor 10. However, if the PNPN switch 9 malfunctions due to a sudden voltage change button or electric surge that occurs on the subscriber terminal 1 side, the battery 11 is supplied to the B line 3 of the subscriber line via the resistor 10. As a result, a current flows through the resistor 10, resulting in a voltage drop. Then, the comparator 13 detects the voltage drop generated in the resistor 10, and the malfunction determination holding circuit 14 determines the conditions under which the current is flowing through the resistor 10 and a voltage drop has occurred, and the ringing sending circuit 6 P of
The conditions for malfunction of the NPN switch 9 are detected and held and displayed on the higher-level control device, and the higher-level control device performs malfunction recovery control of the ringing sending circuit 6.

〔Effect of the invention〕

As explained above, the present invention provides a malfunction recovery circuit that detects the current flowing through the resistance of the ringing sending circuit using a comparator, detects the malfunctioning condition of the PNPN switch of the syringing sending circuit using an AND circuit, and maintains the condition. By providing this, it is possible to suppress wasted power consumption due to malfunction of the PNPN switch in the ringing sending circuit, and furthermore, the higher-level control device can immediately know the abnormal state of the ringing sending circuit. Restoration control of the transmission circuit can be performed, which has the effect of improving service to subscribers.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the present invention. 1...Subscriber terminal, 2...Subscriber line A, 3
...Subscriber line B line, 4...Switch circuit, 5
...Power supply circuit, 6...Ringing sending circuit, 7
... Ringing signal source, 8.9 ... PNPN switch, 10 ... ◆ Resistor, 11 ... Battery, 12
... Ring trip circuit, 13 ... Comparator, 1
4... Malfunction determination holding circuit, 15... AND circuit, 16... Latch circuit, 17... Malfunction later circuit.

Claims (1)

[Claims] The A line and B line of a two-wire subscriber line are connected to the subscriber terminal, a switch circuit switches the voltage polarity applied to the A line and the B line, and a power supply circuit supplies power to the subscriber terminal. In the ringing state, a ringing signal is supplied from the ringing sending circuit to the A line of the subscriber line via the first PNPN switch, and a second PNPN switch is supplied to the B line.
In a subscriber circuit of a telephone exchange that supplies a predetermined battery through an N switch and a resistor and detects a ring trip due to loop formation at a subscriber terminal in a ring trip circuit, the battery and the second PNPN switch are connected to each other. A comparator detects the current flowing through the resistor connected between the subscriber lines, and an AND circuit detects and holds the condition where the ring trip state is not present and a current flows through the resistor and a voltage drop occurs. A malfunction recovery circuit is provided to detect and hold a malfunction condition of the second PNPN switch that controls the connection of a predetermined battery to the B line of A malfunction of the second PNPN switch that controls connection of a predetermined battery to line B of the subscriber line of the ringing transmission circuit is detected, and malfunction recovery control of the ringing transmission circuit is performed. Malfunction recovery method for ringing sending circuit.