JP2511695B2 - Subscriber status monitoring device - Google Patents

Description

The present invention relates to a subscriber status monitoring device in a subscriber circuit of a time-division switch, which prevents an erroneous trip by a loop monitoring circuit during transmission of a ringing signal, and also a ring trip circuit, a scan output circuit, and a relay. A relay driver circuit 7 for controlling the intermittent operation of the ringing signal transmission relay RL based on the intermittent SD signal from the control unit for the purpose of integrating the subscriber status monitoring device including the driver circuit and the loop monitoring circuit into an LSI.
A ring trip circuit 5 for detecting an off-hook of the telephone by a change in current in a calling signal transmission loop formed via a subscriber line to a subscriber telephone by a contact rl of the call signal transmitting relay, and a current supply to the telephone. Loop monitoring circuit 4 for detecting the on / off hook of the telephone in the power feeding circuit 3 for scanning, and scan output for sending signals to the control unit in response to the detection signals of the ring trip circuit 5 and the loop monitoring circuit 4, respectively. In the subscriber status monitoring device including the circuit 6, a scan output stop circuit 9 is added to operate and recover after delaying the operation and recovery of the relay driver circuit by a predetermined time each time the SD signal from the control unit is received. The stop circuit prevents the loop monitor circuit from sending the detection signal to the scan output circuit until the operation is restored. It has the ability.

[Industrial applications]

The present invention relates to a subscriber status monitoring device for a digital subscriber circuit of a time division switch.

The subscriber circuit in the time-division exchange is highly integrated by implementing LSI, and the ring trip circuit that detects the off-hook of the subscriber telephone during the call signal transmission and the call signal transmission relay of the detection signal from the ring trip circuit Highly integrated LSIs are required for the scan output circuit that controls restoration and for the loop monitoring circuit that detects on / off hooks of subscriber telephones in the power supply circuit.

[Conventional technology]

A circuit configuration diagram of a conventional subscriber status monitoring device is shown in FIG. In the figure, 1 is a subscriber telephone, 2 is a ringer signal generator, 3 is a power supply circuit, 4 is a loop monitoring circuit, 5 is a ring trip circuit, 6 is a scan output circuit, 7 is a relay driver circuit, and 8 is a ringing signal. The sending relay RL is shown.

In FIG. 3, the calling signal transmission relay 8 is intermittently operated through the relay driver circuit 7 by the SD signal which is the intermittent signal from the control unit, and the ringing signal from the ringer signal generator 2 is caused by the intermittent operation of the relay contact rl. Is sent to the subscriber telephone set 1. When the subscriber off-hooks the telephone for a response, the voltage across the detection resistor RO is detected and the detection signal is sent from the ring trip circuit 5 to the scan output circuit, and the SCN signal is sent from the scan output circuit 6 to the control unit. As a result, the control unit stops sending the SD signal, and the intermittent operation of the call signal sending relay via the relay driver circuit 7 is stopped. When the intermittent operation of the relay contact rl stops, the subscriber telephone set 1 is connected to the power feeding circuit 3 via the stationary position of the rl contact of the subscriber line, and the subscriber circuit current is supplied.
The loop monitoring circuit 4 also monitors the subscriber's on / off hook. If the subscriber goes off-hook when the call signal is relayed intermittently and the call signal is being sent intermittently, especially when the contact rl is in the stationary state shown in the drawing when the call signal send relay 8 is restored, the loop monitor circuit 4 detects and sends the detection signal to the scan output circuit 6, the scan output circuit sends the SCN signal to the control unit. As a result, the control unit stops sending the SD signal, stops the intermittent operation of the signal sending relay 8 via the relay driver circuit 7, and keeps the relay contact rl at the stationary position. Since the loop monitor circuit 4 monitors the loop state of the subscriber circuit when the call is connected, if the subscriber ends the call and goes on hook, this is detected and a detection signal is sent to the scan output circuit 6. As a result, the scan output circuit sends a corresponding signal to the control unit, and particularly in the case of on-hook, the control unit confirms on-hook due to the end of the call.

In the above circuit, the loop monitoring circuit 4 constitutes a part of the power feeding circuit 3, and the subscriber telephone 1 is connected to the ground-Q2-R2-rl- (B).
-TEL- (A) -rl-R3-Q3-V _BB supplies the subscriber circuit current through the path, and the voltage across resistors R2 and R3 is controlled by the two voltage / current converters V / 1 of loop monitoring circuit 4. Current is converted,
The sum of currents from the adder flows through the resistor R1, and controls the scan output circuit 6 by comparing the voltage drop of R1 with the limit voltage Vth2.
Sends the SCN signal to the controller.

In the above circuit operation, when the ringer signal generator 2 sends a ringing signal to the telephone 1 by disconnecting the relay contact rl of the ringing signal sending relay 8, the ringing signal is intermittently sent to the phone 1 by the intermittent operation of the rl contact. When the rl contact returns to the rest position in the figure, the electric charge accumulated in the telephone 1 by the ringer signal flows into the power feeding circuit 3 through the rl contact, and the loop monitoring circuit 4 connected to the power feeding circuit 3
May malfunction. In order to prevent this, the conventional relay contact rl is connected to a filter circuit of C and R to reduce the inflowing electric charge and prevent an erroneous trip due to a malfunction of the loop monitoring circuit 4.

[Problems to be Solved by the Invention]

However, the above-mentioned conventional circuit is not a complete measure for preventing erroneous trips, and has the drawback of increasing the number of parts such as C and R. Therefore, according to the present invention, an erroneous trip due to a loop monitoring circuit is prevented, and external parts are not used,
The purpose is to build a circuit so that it can be easily integrated into an LSI by the circuit configuration of transistors.

[Means for solving the problem]

According to the present invention, the above object is to provide a relay driver circuit 7 for controlling the intermittent operation of the calling signal transmitting relay RL based on the intermittent SD signal from the control unit as shown in the principle configuration diagram of FIG.
A ring trip circuit 5 for detecting an off-hook of the telephone by a change in current in a calling signal transmission loop formed through a subscriber line to a subscriber telephone by a contact rl of the call signal transmitting relay, and a current supply to the telephone. Loop monitoring circuit 4 for detecting the on / off hook of the telephone in the power feeding circuit 3 for
In the subscriber status monitoring device, which includes a scan output circuit 6 that sends a signal to the control unit in response to each detection signal of the ring trip circuit 5 and the loop monitoring circuit 4, when the SD signal from the control unit is received, A scan output stop circuit 9 that operates and recovers after a predetermined time from the operation and recovery of the relay driver circuit is added, and the scan output stop circuit switches from the loop monitoring circuit to the scan output circuit until the operation is recovered. This is achieved by a subscriber status monitoring device characterized by having a function of preventing the transmission of a detection signal.

[Action]

When the ringer signal generator 2 intermittently sends the ringing signal to the subscriber telephone 1 by the intermittent operation of the ringing signal transmission relay 8 and the telephone 1 is off-hook due to the subscriber response, the ring trip circuit 5 changes the voltage across the detection resistor R0. Monitor and the detection signal is sent to the scan output circuit 6 and the SNC
The signal is sent to the control unit. From the controller
When the SD signal is stopped, the calling signal sending relay 8 stops the intermittent operation via the relay driver circuit 7, and when the contact rl returns to the stationary position, sending of the calling signal is stopped.

At the same time, the subscriber telephone set 1 is connected to the power feeding circuit 3 to supply a current to the telephone set, and the loop monitoring circuit detects the off-hook state of the telephone set by the current at this time. The loop monitoring circuit also detects the on-hook of the telephone after the call ends.

However, when the ringing signal is being sent to the telephone by the intermittent operation of the ringing signal sending relay, when the contact point rl is interrupted and the contact point returns to the stationary position, the telephone
It is connected to the power supply circuit via rl.

In this case, the call signal is being sent to the telephone, the telephone is not answered, and the telephone is on-hook. Since the current is not supplied from the power feeding circuit, the loop monitoring circuit is normally in a non-operating state.

However, when the contact rl returns to the stationary position during the ringing signal transmission, the electric charge accumulated in the telephone flows into the power feeding circuit 3, and the loop monitoring circuit thereby erroneously detects that the telephone is off-hook corresponding to the subscriber's response and detects the detection signal. May occur.

However, according to the present invention, a scan output stop circuit is provided, and this scan output stop circuit receives an intermittent SD signal from the control unit and is intermittently controlled, but its operation and recovery are similarly controlled by the SD signal. There is a predetermined delay from the operation and recovery of the relay driver circuit.

The scan output stop circuit prevents the detection signal from being sent from the loop monitor circuit to the scan output circuit during the period from this operation to the recovery.

That is, even if the loop monitor circuit malfunctions due to the accumulated charge from the telephone set via the subscriber line when the contact of the ringing signal transmission relay returns from the operating position to the stationary position while the calling signal is being sent to the telephone set, the scan output is stopped at this time. Since the circuit is still in operation, the signal from this loop monitor circuit is not sent to the scan output circuit.

Further, the subscriber circuits as shown in FIG. 1 are mounted in close contact with each other in one package every 8 or 16 circuits.
Therefore, when the ringing signal is sent by the adjacent subscriber circuit,
Alternatively, when the subscriber telephone connected to the adjacent subscriber circuit is dialing, those signals are induced as a noise signal to the subscriber circuit shown in FIG. 1, and the noise signal causes the subscriber circuit of FIG. Therefore, the loop monitoring circuit may malfunction even when the ringing signal transmission relay is in operation.

However, in the present invention, the scan output stop circuit operates
Since no signal is sent from the loop monitor circuit to the scan output circuit during restoration, even if the loop monitor circuit malfunctions due to the noise signal induced from the adjacent subscriber circuit as described above, the scan output circuit Is not affected by this at all.

〔Example〕

FIG. 2 is a circuit diagram of an embodiment of the subscriber status monitoring device according to the present invention, particularly focusing on the scan output circuit and the loop monitoring circuit.
Shown in the figure.

In the figure, 4 is a loop monitoring circuit, 6 is a scan output circuit, 7 is a relay driver circuit, 9 is a scan output stop circuit, and the ring trip circuit 5 is omitted.

When an intermittent SD signal is input from a control unit (not shown in the figure), the call signal transmission relay 8 in FIG. 1 operates via the relay driver circuit 7, and the subscriber telephone set via its contact point rl and the subscriber line. A ringing signal transmission loop for 1 is formed, and when the telephone goes off-hook, the ring trip circuit 5 detects this and the scan output circuit 6 outputs the detection signal.
To send to.

When the subscriber responds to the ringing signal and puts the telephone in the off-hook state, a current flows from the power feeding circuit through the telephone, and when this is detected by the loop monitoring circuit, the voltage across the resistor R ₁ and the limit voltage Vth 2 are detected. Is also compared, the transistor Q ₉ operates, and the detection signal from the loop monitoring circuit is sent to the scan output circuit 6 as shown in FIG.

On the other hand, in the present invention, the scan output stop circuit 9 is provided, and the SD signal is input to the resistor Rx via the delay circuit D.
Therefore, an intermittent signal delayed by a predetermined time from the rising and falling of the SD signal is generated in the resistor Rx. Then, from the rising edge to the falling edge of this signal, the transistor Q ₇ becomes conductive and the transistor Q ₈ maintains the operating state.

During the call signal transmission, the contact of the call signal transmission relay changes from the operating state to the stationary state, the electric charge accumulated in the telephone flows to the loop monitoring circuit of the power feeding circuit through this contact, and the loop monitoring circuit detects an erroneous off-hook. , Generate a detection signal and generate a potential difference in the resistor R ₁ . However, in the conducting state of the transistor Q _7, the potential difference between the resistor R ₁ is a transistor Q ₈
The transistor Q ₈ continues to operate without any change in the state. Therefore, the detection signal from the loop monitoring circuit is not given to the scan output circuit 6.

Further, even if the loop monitor circuit malfunctions due to the noise signal induced from the adjacent subscriber circuit in the operating state of the call signal transmission relay, the scan output circuit is not affected at all.

〔The invention's effect〕

As described above, when the contact of the ringing signal transmission relay is switched from the operating position to the rest position when the ringing signal is transmitted to the telephone, the charge accumulated in the telephone flows to the loop monitoring circuit in the power feeding circuit, and the off-hook occurs. Since the detection signal is not sent to the scan output circuit and blocked even if it is erroneously detected, the SCN signal is not sent from the scan output circuit to the control unit, and therefore, the calling signal transmission is not terminated by mistake.

Further, even if the loop monitor circuit malfunctions due to the noise signal induced from the adjacent subscriber circuit when the contact of the ringing signal transmission relay is in the operating position, the scan output circuit does not operate by it.

Furthermore, the circuit of the present invention is composed of only transistors,
Since circuit components can be built into the LSI with a circuit suitable for conversion to I, there is no need to add external components unlike conventional circuits.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention, FIG. 2 is a circuit block diagram of an embodiment of the present invention, and FIG. 3 is a circuit block diagram of a conventional example. In the figure, 1 is a subscriber telephone, 2 is a ringer signal generator, 3 is a power supply circuit, 4 is a loop monitoring circuit, 5 is a ring trip circuit, 6 is a scan output circuit, 7 is a current driver circuit, and 8 is a ringing signal transmission. A relay, 9 is a scan output stop circuit, and 12 is a comparator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuzo Yamamoto 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (56) Reference JP 60-80352 (JP, A) JP 1-158861 (JP, A)

Claims (1)

(57) [Claims] 1. A relay driver circuit 7 for controlling the intermittent operation of a calling signal transmitting relay RL based on an intermittent SD signal from a control unit, and a contact line rl of the calling signal transmitting relay to connect a subscriber line to a subscriber telephone. A ring trip circuit 5 for detecting an off-hook of a telephone by a change in current in a call signal transmission loop formed via a loop monitor for detecting an on-off hook of a telephone in a power supply circuit 3 for supplying a current to the telephone. In a subscriber state monitoring device including a circuit 4 and a scan output circuit 6 which sends a signal to the control unit in response to each detection signal of the ring trip circuit 5 and the loop monitoring circuit 4, an SD signal from the control unit When receiving, scan output stop circuit 9 is added, which operates and restores after a predetermined time from the operation and restoration of the relay driver circuit. The subscriber status monitoring device, wherein the channel output stop circuit has a function of preventing the detection signal from being sent from the loop monitoring circuit to the scan output circuit until the operation is restored.