JPS62186639A - Ring trip system - Google Patents

Abstract

PURPOSE:To attain ring trip even if a subscriber line is grounded and to quicken the response time by providing a ring trip circuit to lines A, B of the subscriber line respectively. CONSTITUTION:Since the time constant of the ring trip circuit 8 connected to the subscriber line A4 is selected small, the ring trip reply time is fast. On the other hand, the time constant of the ring trip circuit connected to the subscriber line B line 3 is selected larger and the response time is longer, but even if the subscriber line is grounded, the ring trip is attained. Since both outputs of the ring trip circuits 6, 8 are in OR connection, even if any circuit is subjected to ring trip, a ring trip signal is obtained. Thus, the response time is quickened and the ring trip is attained even if the subscriber line is grounded.

Description

[Detailed Description of the Invention] [Summary] A ring trip circuit is provided on each of the A line side and the B line side of the subscriber line, and the outputs of both ring trip circuits are connected to OR to take out the ring trip signal. The aim is to shorten the response time of the system and ensure ring tripping even in the event of a ground fault in the subscriber line.

[Industrial application field]

The present invention relates to an improvement of a ring trip method in a subscriber line circuit of an exchange.

Ring trip is intended for a subscriber to stop ringing by off-hooking the incoming telephone that is receiving the ringing tone, and detects the voltage change at the detection point due to the formation of a DC loop in the subscriber line. However,
When the telephone is turned on, an alternating current of the ringing signal is flowing to the detection point, and the ring trip circuit has an integrating circuit to avoid malfunction. This increases the ring trip response time.

The ring trip circuit is also required to operate even in the event of a ground fault in the subscriber line.

Therefore, it is desired to provide a ring trip circuit that has a short ring trip response time and operates reliably even in the case of a subscriber line ground fault.

[Conventional technology]

FIG. 3 is a diagram of a conventional ring trip system.

In FIG. 3, the calling signal from the calling signal transmitter 1 connected to the ground is transmitted through a calling signal transmitting resistor R1 and a relay 2 (R
B line 3. via the contact point rt' of T). Bell circuit of telephone 5,
A line 4. The signal flows from the contact point rt' of the relay 2 and the calling signal receiving resistor R2 to the power source VB, causing the bell of the telephone 5 to ring.

In this case, the ring trip circuit 6 does not operate with the alternating current of the calling signal due to the integration circuit formed by the resistor R61 and the capacitor C61.

When the telephone 5 goes off-hook and the hook switch H5 closes while sending a ringing signal, the A line 4. Since the B line 3 is connected in a DC manner by the telephone 5, the voltage at the (-) input terminal connected to the capacitor C61 of the comparator 61 (CP) of the ring trip circuit 6 is applied to the (+) input terminal. The current threshold voltage VthB will be exceeded,
Comparator 61 issues a ring trip signal to operate relay 2 and connect telephone 5 to power supply/monitoring circuit 7 via relay contacts rt', rt'.

[Problem that the invention seeks to solve]

In the conventional method described above, in order to prevent malfunction, the time constant of the integrating circuit is increased, that is, the capacitor C61
It is necessary to make the value of

Therefore, there is a problem that it takes a long time to obtain the ring trip signal after the telephone 5 goes off-hook.

[Means for solving problems]

FIG. 1 is a diagram showing the principle of the ring trip method of the present invention.

In FIG. 1, numeral 1 is a calling signal transmitter, and the calling signal is transmitted from the earth through a calling signal transmitting resistor R1, a B line 3, and a telephone set 5.
．． A line 4. The signal flows to the power supply VB via the calling signal receiving resistor R2.

6 is a ring trip circuit connected to the ring signal transmitting resistor R1, which is the same as in the conventional example; 8 is a ring trip circuit newly connected to the ring signal receiving resistor R2 on the A line side; The output of the trip circuit is OR-connected.

[Effect]

The off-footer of the telephone 5 causes the resistance R1 for transmitting a ringing signal to
DC voltage is generated on the B wire 3 side of the ring signal receiving resistor R2 and the A wire 4 side of the ring signal receiving resistor R2, and the ring trip circuit 6 detects the voltage.
, 8 sends out a ring trip signal.

When the time constant of the ring trip circuit 8 is small, the ring trip response time is fast.

A calling signal transmitting resistor R1 is provided to protect the calling signal transmitter 1.
has a large resistance value. Therefore, the time constant of the ring trip circuit 6 becomes large and the ring trip response time takes a long time, but a ring trip is possible even in the case of a ground fault in the subscriber line.

Since the re-outputs of the ring trip circuits 6 and 8 are OR-connected, a ring trip signal can be obtained even if either circuit is ring tripped, resulting in a short ring trip response time and resistance to subscriber line ground faults. You can get the ring trip method.

〔Example〕

The present invention will be specifically explained below with reference to illustrated examples.

FIG. 2 is a diagram of a ring trip system according to an embodiment of the present invention. The same reference numerals indicate the same objects throughout the figures.

In the figure, the example value of the calling signal transmission resistor R1 is approximately IK
Ω, the example value of the resistor R61 in the ring trip circuit 6 is 100K to 200Ω, the example value of the capacitor C61 is about lOμF, while the example value of the ringing signal receiving resistor R2 is 200 to 300Ω, An example of the value of the resistor 81 in the ring trip circuit 8 is 100 to 200 Ω, and an example of the value of the capacitor C81 is 0.1 to 0.5 μF.
The time constant of ring trip circuit 8 is the same as ring trip circuit 6.
It is much smaller than the previous model and has a faster ring trip response time.

That is, the (-) of the comparator 81 of the ring trip circuit 8
) When the input terminal voltage exceeds the threshold voltage V thA applied to the (+) input terminal in a short time by the small time constant, the comparator 81 sends out a ring trip signal via the OR element 9. relay 2
is activated, the ringing signal is stopped at the relay contacts rt' and rt', and the telephone 5 is connected to the power supply/monitoring circuit 7.

The ring trip circuit 6 performs a ring trip later than the ring trip circuit 8, but it can perform a ring trip even if the subscriber line has a ground fault of about 500Ω, and even if the ring trip circuit 8 does not ring trip, the relay 2 is activated. Because it works, it increases credibility.

〔Effect of the invention〕

According to the present invention, ring trip circuits with different time constants are provided on each of the A line side and the B line side, so the response time is fast.
In addition, there is an effect that a ring trip can be performed even if the subscriber line has a ground fault.

[Brief explanation of drawings]

Figure 1 is a principle diagram of the ring trip method of the present invention. FIG. 2 is a diagram of a ring trip system according to an embodiment of the present invention. FIG. 3 is a diagram of a conventional ring trip system. In the figure, 1 is a calling signal transmitter; 2 is a relay, 3 is B line, 4 is the A line, 5 is a telephone, 6.8 is the ring trip circuit, 7 is a power supply/monitoring circuit; R1, R2, R61, R81 are resistors, C61 and C81 are capacitors, 61.81 indicates a comparator.

Claims (1)

[Claims] A ring trip circuit (6) is connected to the B line (3) side of the subscriber line, and a ring trip circuit (8) is also provided on the A line (4) side of the subscriber line, A ring trip method characterized by a configuration in which a ring trip signal can be extracted from either output of both ring trip circuits.