JPH0417449A - Network controller for no ringing incoming call - Google Patents

Abstract

PURPOSE:To attain normal operation even when the polarity of a telephone line is selected in any direction by starting a no ringing detection means with a voltage detection signal when a voltage detection means detects a voltage from a telephone line to be a prescribed voltage or over and detecting a no ringing incoming signal by the detection means. CONSTITUTION:A polarity of voltage of a telephone line is made unidirectional by using a diode bridge 2 connecting between the telephone lines and when the voltage from the telephone line with the constant polarity reaches a 1st prescribed voltage or over, a switch means 3 is conductive, the voltage from the telephone line is fed to a voltage detection means 4 via a switch means 3 and when the voltage from the telephone line reaches a 2nd prescribed voltage or over, the voltage detection means 4 generates a voltage detection signal, the voltage detection signal starts the no ringing detection means 6 to detect a no ringing incoming signal. Thus, the telephone line is connected independently of the polarity of the telephone line, ease of mount of the controller is attained and risk of mis-connection is not caused.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a no-ringing incoming network control device that is connected to a telephone line and is called by a no-ringing incoming call from the exchange side.

(Prior Art) This type of no-ringing terminating network control device includes, for example, a circuit as disclosed in Japanese Patent Publication No. 63-28549. The network control device disclosed in Japanese Patent Publication No. 63-28549 has a high voltage detection circuit that includes a high voltage detection circuit at one terminal 9a of telephone line connection terminals 9a and 9b, as shown in FIG. is connected to the DC input end of the analog switch 10, and a reverse current blocking diode is connected to the other terminal 9b.
The common return terminal side of the high voltage analog switch 10 is connected through the cable 11. This high voltage analog switch 10 maintains a cut-off state when a DC voltage higher than a first predetermined voltage is input, and becomes a conductive state when a DC voltage lower than the first predetermined voltage is input. , has a function of passing the DC voltage and AC voltage with low loss. Further, when this high voltage analog switch 10 is supplied with a release signal 14 from the terminal device 13, it enters a cut-off state and maintains this state.

The DC voltage from the telephone line connection terminals 9a and 9b that appears on the output side when this high voltage analog switch IQ is turned on is as follows:
The signal is input to a low voltage analog switch 12 connected to the output of the high voltage analog switch 10, and the low voltage analog switch 12 determines the relationship with the operation start voltage of the terminal device 13. That is, this low voltage analog switch 12 maintains a cut-off state when the voltage is less than a second predetermined voltage, which is smaller than the first predetermined voltage, and becomes a conductive state when the voltage exceeds the second predetermined voltage. Once the conductive state is established, the conductive state is maintained even if the input DC voltage becomes less than the second predetermined voltage.

On the DC output side of this low voltage analog switch 12,
For example, a terminal device 13 for data collection is connected.

This terminal device 13 starts operating with power supplied from the telephone line connection terminals 9a and 9b when the low voltage analog switch 12 is turned on. Then, it determines the presence or absence of reception detection of a specific call signal sent superimposed on the inverted DC voltage sent from a solid device not shown in the diagram connected via the telephone line, and If the calling signal cannot be received within the time, a release signal 14 is supplied to the high voltage analog switch 10 to shut off the high voltage analog switch 10.

(Problems to be Solved by the Invention) In the conventional network control device disclosed in the above-mentioned Japanese Patent Publication No. 63-28549, one terminal 9b of the telephone line connection terminals 9a and 9b is Since the telephone line connection terminals 9a, 9b and the telephone line must be connected with the same polarity, there is a problem that the telephone line connection terminals 9a, 9b and the telephone line will not operate normally if they are connected with the opposite polarity.

The present invention has been made in view of the above, and an object of the present invention is to provide a no-ringing incoming network control device that operates normally no matter which direction the polarity of the telephone line is connected. .

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the no-ringing incoming network control device of the present invention provides a no-ringing incoming network control device that is connected to a telephone line and is called by a no-ringing incoming call from the exchange side. A network control device comprising: a diode bridge connected between telephone lines so as to set the voltage polarity of the telephone line in a fixed direction; Once the voltage rises above the voltage, switching means becomes conductive and passes the output voltage of the diode bridge, and the output voltage of the diode bridge passes through the switching means, and the output voltage becomes a second predetermined voltage. In this case, a voltage detecting means for generating a voltage detecting signal, and a no-ringing device connected in an alternating current manner to the output of the switching means, activated by the voltage detecting signal of the voltage detecting means, and detecting the no-ringing incoming signal. The present invention is characterized in that it comprises a detection means, and a timer means that is activated by the voltage detection signal of the voltage detection means and makes the switch means non-conductive after a predetermined period of time when a release signal from the outside is not supplied.

(Function) In the no-ringing incoming network control device of the present invention, the voltage polarity of the telephone line is set in a fixed direction by a diode bridge connected between the telephone lines, and the voltage from the telephone line having the polarity in the fixed direction is When the voltage exceeds a predetermined voltage, the switch means becomes conductive, and the voltage from the telephone line is supplied to the voltage detection means via the switch means, and when the voltage from the telephone line exceeds a second predetermined voltage in the voltage detection means, the voltage A detection signal is generated, the no-ringing detection means and the timer means are activated by the voltage detection signal, and the switch means is made non-conductive after a predetermined period of time when a release signal is not supplied to the timer means from the outside.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram showing the configuration of a no-ringing terminating network control device according to an embodiment of the present invention. The no-ringing terminating network control device shown in the figure has telephone line connection terminals 1a and lb connected to a telephone line, and the telephone line connection terminals 1a and lb are connected to the input of a diode bridge 2.

This diode bridge 2 has a telephone line connection terminal 1a:
It converts the polarity of the DC voltage from the telephone line supplied from Lb to a certain direction, and the diode bridge 2
The output voltage from the diode bridge 2 whose polarity is set in a fixed direction, that is, the DC voltage from the telephone line, is supplied to the high voltage switch circuit 3. This high voltage switch circuit 3
becomes conductive when the DC output voltage from the diode bridge 2 rises above the second predetermined voltage, and continues to maintain the conductive state even if the DC output voltage becomes lower than the second predetermined voltage. It looks like this.

Furthermore, when the high voltage switch circuit 3 is in the conductive state, when the DC output voltage from the diode bridge 2 becomes equal to or higher than the first predetermined voltage, which is higher than the second predetermined voltage, the high voltage switch circuit 3 enters the cut-off state, and thereafter the DC output is switched off. Even if the voltage becomes lower than the first predetermined voltage, the cutoff state is maintained. Furthermore, when the high voltage switch circuit 3 is in the conductive state, when the cutoff signal 9 is released from the outside, it enters the cutoff state, and thereafter continues to maintain the cutoff state even after the cutoff signal 9 is released. ing.

When the high voltage switch circuit 3 becomes conductive, the DC output voltage from the diode bridge 2 is supplied to the subsequent voltage detection circuit 4 via the high voltage switch circuit 3. The voltage detection circuit 4 starts operating with the power supplied from this DC voltage, and outputs a detection signal 8 when the DC voltage reaches or exceeds a third predetermined voltage smaller than the second predetermined voltage.

Therefore, when the high withstand voltage switch circuit 3 changes from the cut-off state to the conductive state, the voltage detection circuit 4 also always generates the detection signal 8. This detection signal 8 is supplied to the timer circuit 5 and the no-ringing signal detection circuit 6 to activate these circuits.

When activated by the detection signal 8 from the voltage detection circuit 4, the timer circuit 5 outputs a cutoff signal 9 after a certain period of time, and supplies the cutoff signal 9 to the high voltage switch circuit 3. 3 is turned off. Further, if the timer circuit 5 is supplied with a release signal 16 from the terminal device 7 before outputting the cutoff signal 9, the timer circuit 5 stops the timer operation and does not output the cutoff signal 9.

The no-ringing signal detection circuit 6 is AC-connected to the output of the high-voltage switch circuit 3 via a capacitor 15, and when activated by the detection signal 8 from the voltage detection circuit 4, the no-ringing signal detection circuit 6 detects the diode bridge 2
Detects the no-ringing incoming signal (NR8 signal) superimposed on the DC voltage from the terminal device 7, and transmits this detection signal to the terminal device 7.
supply to. When the terminal device 7 is supplied with the detection signal 8 from the no-ringing signal detection circuit 6, it determines that it has been called, and supplies a release signal 16 to the timer circuit 5, thereby stopping the operation of the timer circuit 5. However, the timer circuit 5 is prevented from generating the cutoff signal 9.

FIG. 2 is a detailed circuit diagram of the no-ringing terminating network controller of FIG. As shown in detail in the figure, the high voltage switch circuit 3 has a switching transistor Q31 connected in series to the output of the diode bridge 2, and the output of the diode bridge 2 connected to the emitter of the transistor Q31 is , a resistor R34, a Zener diode ZD31 having a Zener voltage corresponding to the second predetermined voltage, and a transistor Q32. Furthermore, a resistor R3 is connected between the base of the transistor Q31 and the cathode of the Zener diode ZD31.
5 is connected, and a transistor Q34 is connected in parallel to both ends of the Zener diode ZD31. The base of the transistor Q34 is connected to the diode D33 and the resistor R.
36 to the collector of the transistor Q31, and a resistor R38 is connected between the base and emitter of the transistor Q34.

Further, the output of the diode bridge 2 is connected to the ground via a resistor R32 and a transistor Q3B, and is also connected to the ground via a resistor R31, a diode D31, and a capacitor C31, and a transistor 033.
The collector of is connected to the base of the transistor Q32. Further, the connection point between the resistor R31 and the diode D31 is connected to the transistor Q3 via the diode D32.
2 collector. The connection point between the diode Q31 and the capacitor C31 is connected to the transistor 033.
and the cathode of a diode D36 via a resistor R33. The anode of the diode D36 is connected to the timer circuit 5,
The cutoff signal 9 is supplied from the timer circuit 5.

Furthermore, the collector of the transistor Q31 is connected to a resistor R37,
It is connected to the connection point between the resistor R33 and the diode D36 via a Zener diode ZD32 and a diode D35 having a Zener voltage corresponding to the first predetermined voltage.

Further, the voltage detection circuit 4 includes the transistor Q31
The voltage comparator circuit has a stabilized power supply 41 that operates by being supplied with the DC output voltage from the diode bridge 2, that is, the DC voltage from the telephone line, and operates with the voltage from the stabilized power supply 41. It has 43. Further, the collector of the transistor Q31, that is, the input of the stabilized power supply 41, is connected to the ground through resistors R41 and R42, thereby converting the DC voltage supplied through the transistor Q31 to the divided voltage. Resistor R4
1, the voltage at the connection point of R42 is supplied to one input of the voltage comparison circuit 43, and a reference equal to the third predetermined voltage of the reference voltage source V41 supplied to the other input of the voltage comparison circuit 43; It is designed to compare with voltage. The voltage comparison circuit 43 compares the divided voltage of the resistors R41 and R42 with a third predetermined voltage from the reference voltage source V41, and outputs the detection signal 8 when the divided voltage is larger than the third predetermined voltage. do.

Next, the operation of the network control device configured as described above will be explained.

First, when the voltage from the telephone line supplied between the telephone line connection terminals 1a and lb rises from a low voltage to a second predetermined voltage, which is the Zener voltage of the Zener diode ZD31, regardless of polarity, this voltage The polarity is aligned in a certain direction by the bridge 2, and the voltage is supplied to the high voltage switch circuit 3 as a positive polarity voltage. This voltage is then supplied to the base of the transistor 03B via the resistor R31 and diode D31 of the high voltage switch circuit 3, and is also supplied to the base of the transistor Q32 via the resistor R32.
is supplied to the base of transistor Q33 and tries to energize both transistors, but capacitor C3 is connected to the base of transistor Q33.
1 is connected, and the voltage supplied to the base of transistor Q33 is charged to capacitor C31, so the voltage at the base of transistor 03B does not rise, and therefore transistor Q33 does not conduct. On the other hand, transistor Q
32 is connected to the collector of transistor Q3B, but since transistor 033 is not conductive, the base potential of transistor QB2 rises and transistor QB2 is conductive.

As a result, the potential of the resistor R31 decreases via the diode D32, and the base potential of the transistor 033 becomes equal to or less than the Vf voltage, so that the transistor Q33 is kept in a cut-off state and only the transistor Q32 is stabilized in a conductive state.

On the other hand, the DC voltage from the diode bridge 2 is applied to the resistor R34 connected to the emitter of the transistor Q31.
Zener diode ZD31 is supplied to Zener diode ZD31 through the path of conductive transistor Q32, but since the DC voltage at this time is larger than the second predetermined voltage which is the Zener voltage of Zener diode ZD, Zener diode ZD31 is conductive. state, a current flows, a voltage is generated across the resistor R34, and when this voltage becomes the Vf voltage of the transistor Q31, the transistor Q3
1 is conductive. When the transistor Q31 becomes conductive, a voltage is generated on the collector side through the transistor Q31,
As a result, a current flows through the resistor R3g via the resistor R36 and the diode D33, and the voltage across the resistor R38 also causes the transistor Q34 to conduct. transistor Q
When B4 becomes conductive, a current route is formed that bypasses Zener diode ZD31, and thereafter, even if the DC voltage from the telephone line via diode bridge 2 and transistor Q31 decreases, transistor Q31 continues to be conductive.

When the transistor Q31 becomes conductive, a DC voltage is supplied to the voltage detection circuit 4 through the transistor Q31, thereby operating the stabilized power supply 41 and supplying the voltage comparison circuit 4.
3 and the voltage comparison circuit 43.
One input terminal of is supplied with a divided voltage from the connection point of resistors R41 and R42, and is compared with a reference voltage of a third predetermined voltage in a voltage comparison circuit 43. Since the third predetermined voltage is set lower than the second predetermined voltage, the voltage comparison circuit 43 outputs the detection signal 8.

Detection signal 8 from voltage comparison circuit 43 is supplied to timer circuit 5 and no-ringing signal detection circuit 6 to activate these circuits. When the no-ringing signal detection circuit 6 is activated by the detection signal 8, it detects the no-ringing incoming signal that is superimposed on the DC voltage and supplied from the telephone line via the capacitor 15, the high voltage switch circuit 3, and the diode bridge 2. , supplies the detection signal to the terminal device 7.

On the other hand, when the timer circuit 5 is activated by the detection signal 8 from the voltage comparison circuit 43, it starts a timing operation and generates a cutoff signal 9 after a certain period of time. This cutoff signal 9 charges C31 via diode D36 and resistor R33, and when the base potential of transistor Q33 reaches the Vf voltage, transistor Q33 becomes conductive. transistor 0
When 33 becomes conductive, the base potential of transistor Q32 decreases, and transistor Q32 becomes cut off. When transistor Q32 is cut off, transistor Q31
Since the base current of transistor Q31 stops flowing,
becomes blocked. Furthermore, when the transistor Q32 enters the cutoff state, the potential of the diode D32 rises, so no current flows through the diode D32, and even after the cutoff signal 9 is stopped, the transistor 033 remains conductive, and the transistor Q32 is cut off. stable in the state.

Note that, when the timer circuit 5 is supplied with the release signal 16 from the terminal device 7 during the above-described time counting operation, the timer circuit 5 stops the time counting operation and no longer outputs the cutoff signal 9.

The release signal 16 from the terminal device 7 is output from the terminal device 7 when the terminal device 7 is supplied with a detection signal from the no-ringing signal detection circuit 6 and it is determined that the terminal device 7 has been called. Therefore, as described above, if the detection signal is supplied from the no-ringing signal detection circuit 6 to the terminal device 7 before the timer circuit 5 outputs the cutoff signal 9, this causes the terminal device 7 to send the release signal 16 to the timer circuit. 5, the timer circuit 5 stops its timekeeping operation and does not output the cutoff signal 9, so that the state in which the transistor Q32 is conductive and the transistor Q31 is conductive continues.

Also, the DC voltage of the telephone line is connected to the Zener diode ZD3.
When the Zener voltage rises above the first predetermined voltage, which is the Zener voltage of No. 2, a current flows through the Zener diode ZD32, and this current charges the capacitor C31 via R37, the Zener diode ZD32, the diode D35, and the resistor R33, and the above-mentioned interruption occurs. It operates in the same way as when signal 9 is supplied.

In the network control device described above, when a call is received due to polarity reversal of the telephone line voltage and a no-ringing call due to a terminal device selection signal, the diode bridge 2
The output voltage changes and the line voltage increases from a low voltage to a second predetermined voltage or higher, so the high voltage switch circuit 3 becomes conductive, the voltage detection circuit 4 is activated, and the detection signal 8
Output. This detection signal 8 activates the timer circuit 5 and the no-ringing signal detection circuit 6, and the no-ringing signal detection circuit 6 detects a normal no-ringing incoming signal and supplies the detection signal to the terminal device 7. When the terminal device 7 determines that the call is a legitimate call, it supplies a release signal to the timer circuit 5 and stops the generation of the cutoff signal 9 from the timer circuit 5. Therefore, the high voltage switch circuit 3 is not cut off, and the terminal device 7 can perform subsequent data communication processing and the like.

In addition, in the insulation test, the Zener diode ZD32
When a voltage higher than the first predetermined voltage determined by the Zener voltage is applied, the high voltage switch circuit 3 becomes conductive once, but when the Zener diode ZD32 becomes conductive, it outputs a cutoff signal Therefore, the high voltage switch circuit 3 is cut off. The direct current resistance of the line at this time is greater than the combined resistance value of resistors R31 and R32.

Furthermore, in the insulation test, the Zener diode ZD31
When a voltage equal to or lower than the second predetermined voltage equal to the Zener voltage is applied, the Zener diode ZD31 does not become conductive, and the high voltage switch circuit 3 becomes cut off. The DC resistance of the line at this time is resistors R31 and R32
It is more than the combined resistance value.

In the insulation test, if a voltage is applied from the telephone line that is higher than the second predetermined voltage determined by the Zener voltage of Zener diode ZD31 and lower than the first predetermined voltage determined by the Zener voltage of Zener diode ZD32, or If the voltage fluctuates due to a telephone exchange operation other than a call due to an incoming no-ringing call, and the voltage at the output of the diode bridge 2 rises from a low voltage to a second predetermined voltage or higher, as described above, the high voltage switch circuit 3 The transistor Q31 becomes conductive, and the voltage detection circuit 4 outputs the detection signal 8, which activates the timer circuit 5 and the no-ringing signal detection circuit 6, but the no-ringing signal detection circuit 6 detects the no-ringing incoming signal. Since no detection signal is supplied to the terminal device 7 upon detection, the timer circuit 5 outputs a cutoff signal 9 after a certain period of time, thereby placing the high voltage switch circuit 3 in a cutoff state. The direct current resistance of the line at this time is greater than the combined resistance value of resistors R31 and R32.

FIG. 3 is a diagram showing a detailed circuit of the timer circuit 50 in another embodiment of the present invention. Timer circuit 50 shown in the figure
, the output signal of the voltage detection circuit 4 is delayed by a resistor 51 and a capacitor 53, and the capacitor 53 is bypassed by a transistor 55 to cancel the delayed output. This has the advantage that the timer circuit 50 can be operated with voltage from the exchange.

[Effects of the Invention] As explained above, according to the present invention, the voltage polarity of the telephone line is set in a fixed direction by the diode bridge connected between the telephone lines, and the voltage from the telephone line having the polarity in the fixed direction is When the voltage is equal to or higher than the first predetermined voltage, the switch means becomes conductive, and the voltage from the telephone line is supplied to the voltage detection means via the switch means, and the voltage from the telephone line is determined to be equal to or higher than the second predetermined voltage. When the voltage is reached, a voltage detection signal is generated, which activates the no-ringing detection means to detect the no-ringing incoming call signal. Therefore, the telephone line can be connected regardless of the polarity of the telephone line, and the installation is easy. There is no risk of erroneous connection, and there is no problem even if the polarity of the telephone line is changed during other installation work, and calls due to no-ringing incoming calls can be accurately detected. In addition, it is possible to economically realize a switch with a simple configuration that has high impedance for insulation tests performed on telephone lines, does not interfere with insulation tests, and has very low signal loss for data transmission. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a no-ringing incoming network control device according to an embodiment of the present invention, FIG. 2 is a detailed circuit configuration diagram of the network control device of FIG. 1, and FIG. FIG. 4, which is a detailed circuit diagram of a timer circuit according to another embodiment, is a block diagram of a conventional network control device. 2... Diode bridge, 3... High withstand voltage switch circuit, 4... Voltage detection circuit, 5... Timer circuit, 6... No-ringing signal detection circuit, 7... Terminal device.

Claims (1)

[Claims] A no-ringing incoming network control device connected to a telephone line and called by a no-ringing incoming call from the exchange side, comprising: a diode bridge connected between the telephone lines so as to set the voltage polarity of the telephone line in a fixed direction; a switch means connected to the output side of the bridge, which becomes conductive and allows the output voltage of the diode bridge to pass through once the output voltage of the diode bridge rises above a first predetermined voltage; voltage detection means that operates with the output voltage of the diode bridge and generates a voltage detection signal when the output voltage exceeds a second predetermined voltage; a no-ringing detection means that is activated by the voltage detection signal of the means and detects the no-ringing incoming signal; and a no-ringing detection means that is activated by the voltage detection signal of the voltage detection means and detects the switch after a predetermined period of time when a release signal from the outside is not supplied. and timer means for placing the means in a non-conducting state.