JPH04282943A - Network controller for no-ringing incoming call - Google Patents

Abstract

PURPOSE:To surely detect a no-ringing incoming call signal even when a telephone line is connected in any direction. CONSTITUTION:The polarity of voltage of a telephone line applied to telephone line connection terminals 1a, 1b is arranged to a prescribed polarity by a diode bridge 2 and an output voltage from the diode bridge 2 is fed to a voltage detection circuit 3, from which a detection signal is outputted when the voltage reaches a 1st prescribed voltage or over. A polarity storage circuit 4 stores the polarity of the telephone line when the detection signal is outputted from the voltage detection circuit 3 and gives a polarity change signal to a high dielectric strength switch circuit 5 when the polarity of the voltage of the telephone line is changed to make the switch circuit conductive thereby applying an output voltage of the diode bridge 2 to a equipment 6, and then the terminal equipment 6 detects the voltage of the telephone line and detects a no-ringing incoming call signal, the terminal equipment 6 gives a closing signal to the high dielectric strength switch circuit, which is interrupted and the application of the output voltage of the diode bridge 2 to the terminal equipment 6 is stopped.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a no-ringing incoming network control device that is connected between a telephone line and a terminal device, is called by a no-ringing incoming signal from an exchange, and connects the telephone line to the terminal device.

0002

2. Description of the Related Art An example of this type of no-ringing terminating network control device is the circuit 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 including a high voltage detection circuit at one terminal 9a of telephone line connection terminals 9a and 9b, as shown in FIG. analog switch 1
0 is connected to the other terminal 9b, and the common return end of the high voltage analog switch 10 is connected to the other terminal 9b via a backflow blocking diode 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 the high voltage analog switch 10 is turned on is input to the low voltage analog switch 12 connected to the output of the high voltage analog switch 10. This 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 has a second predetermined voltage lower than the first predetermined voltage.
When the voltage is lower than the second predetermined voltage, the cutoff state is maintained, and when the voltage is equal to or higher than the second predetermined voltage, the conduction state is established. Once the conductive state is established, the conductive state is maintained even if the input DC voltage becomes less than the second predetermined voltage.

[0003] A terminal device 13 for data collection, for example, is connected to the DC output side of the low voltage analog switch 12. 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 is determined whether or not reception of a specific call signal sent superimposed on the inverted DC voltage sent from a central device (not shown in the figure) connected via a telephone line is detected;
If the call signal cannot be received within a certain period of time,
A release signal 14 is supplied to the high voltage analog switch 10 to shut off the high voltage analog switch 10.

0004

[Problem to be solved by the invention]
In the conventional network control device disclosed in US Pat.
The telephone line connecting terminals 9a, 9b and the telephone line must be connected with the same polarity, and if they are connected with the opposite polarity, they will not operate properly.

[0005] The present invention has been made in view of the above, and
The object is to provide a no-ringing terminating network control device that operates normally no matter which direction the telephone line polarity is connected. [Structure of the invention]

[0006]

[Means for Solving the Problems] In order to achieve the above object, the no-ringing incoming network control device of the present invention is connected between a telephone line and a terminal device, and is called by a no-ringing incoming signal from the exchange side, A no-ringing terminating network control device for connecting a telephone line to a terminal device, comprising: a diode bridge connected between the telephone lines so as to align voltage polarities of the telephone lines in a certain direction; and a diode bridge connected to the output of the diode bridge; Voltage detection that responds promptly when the output voltage from the diode bridge changes to a first predetermined voltage or higher and outputs a detection signal, and responds with a delay when the output voltage drops below the first predetermined voltage. means, polarity storage means for storing the voltage polarity state of the telephone line when the voltage detection means outputs the detection signal, and outputting a polarity change signal when the voltage polarity of the telephone line changes; and the polarity change signal. conducts to supply the output voltage of the diode bridge to the terminal device, thereby causing the terminal device to perform a telephone line voltage detection operation and a no-ringing incoming signal detection operation, and a closing signal output from the terminal device. and a switch means for stopping the supply of the output voltage of the diode bridge to the terminal device.

[0007]

[Operation] In the no-ringing incoming network control device of the present invention, the voltage polarity of the telephone line is aligned in a fixed direction by the diode bridge, and when the output voltage from the diode bridge having the polarity in the fixed direction becomes equal to or higher than the first predetermined voltage, A detection signal is outputted in response to a prompt response, the polarity of the telephone line at the time this detection signal is outputted is memorized, and the switching means is made conductive by the polarity change signal outputted when the voltage polarity of the telephone line changes. , supplies the output voltage of the diode bridge to the terminal device, thereby causing the terminal device to perform the operation of detecting the telephone line voltage and the operation of detecting the no-ringing incoming signal. and the supply of the output voltage of the diode bridge to the terminal device is stopped.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to 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 1b connected to a telephone line, and the telephone line connection terminals 1a and 1b are connected to the input of a diode bridge 2. This diode bridge 2
is for converting the polarity of the DC voltage from the telephone line supplied from the telephone line connection terminals 1a and 1b into a fixed direction, and the output voltage from the diode bridge 2 whose polarity is set in a fixed direction by the diode bridge 2, That is, the DC voltage from the telephone line is supplied to the voltage detection circuit 3. This voltage detection circuit 3 reacts quickly when the DC output voltage from the diode bridge 2 rises above a first predetermined voltage, and reacts with a delay when it falls below the first predetermined voltage, causing the output signal to change. It is supposed to be done.

The output signal of the voltage detection circuit 3 is connected to one input terminal of a polarity memory circuit 4, and the other input terminal of the polarity memory circuit 4 is connected to the telephone line connected to the input of the diode bridge 2. One of terminals 1a and 1b (Fig. 1
In this case, it is connected to the 1a side). This polarity memory circuit 4 stores the polarity of the telephone line connected to the other input terminal when the output signal of the voltage detection circuit 3 changes from a first predetermined voltage or lower state to a first predetermined voltage or higher state. However, if the polarity of the telephone line stored at this time is different from the previously stored polarity, a polarity change signal is output.

The polarity change signal outputted by the polarity memory circuit 4 is connected to the switch close signal input terminal of the high voltage switch circuit 5, and when the polarity change signal is applied, the high voltage switch of the high voltage switch circuit 5 becomes conductive. state. A DC voltage from a telephone line, which is the output voltage of the diode bridge 2 connected to the input of the voltage detection circuit 3, is supplied to the high voltage switch input side of the high voltage switch circuit 5. When 5 becomes conductive, it is supplied to the terminal device 6 through the high voltage switch.

Further, when the high voltage switch circuit 5 becomes conductive, it outputs a switch conduction state signal to the terminal device 6. The terminal device 6 is activated when a switch conduction state signal is applied from the high-voltage switch circuit 5, starts a timer operation that operates for a predetermined time, and controls the DC voltage from the telephone line supplied through the high-voltage switch circuit 5. Voltage detection is performed, and a no-ringing incoming signal superimposed on this DC voltage is detected. The terminal device operates when the DC voltage from the telephone line becomes equal to or less than a second predetermined voltage, which is lower than the first predetermined voltage, or equal to or higher than a third predetermined voltage, which is higher than the first predetermined voltage, or when the timer is operating for a predetermined time. When no ringing incoming signal is detected, a switch open signal is output that makes the high voltage switch circuit 5 non-conductive.

FIG. 2 is a detailed circuit diagram of the no-ringing terminating network controller of FIG. As shown in detail in the figure, the voltage detection circuit 3 divides the output voltage of the diode bridge 2 by a resistor R31 and a resistor R32 connected in series, and a resistor R31 and a resistor R32 are connected to divide the output voltage of the diode bridge 2. The anode side of the diode D31 and the resistor R3 are connected to the part where the voltage obtained by dividing the output voltage of is outputted.
One end of the diode D31 is connected to the other end of the resistor R33, and one end of the capacitor C31 is connected to the cathode side of the diode D31 and the other end of the resistor R33. Capacitor C
The other end of 31 is connected to one end of resistor R32 and diode bridge 2.
is connected to the ground to which the negative output side end of the resistor R is connected.
33, diode D31, and capacitor C31 constitute a high-speed charge and low-speed discharge integration circuit, and the output of the integration circuit in which resistor R33, diode D31, and capacitor C31 are commonly connected is connected to the non-inverting input terminal of comparator 31, and the output of the integration circuit is connected to the non-inverting input terminal of comparator 31. The positive output terminal of the reference power supply 32 is connected to the inverting input terminal of the reference power supply 31 . The negative output terminal of the reference power source 32 is connected to ground, and this reference power source 3
2 and the output voltage of the diode bridge 2 are divided by the resistor R31 and the resistor R32, and the voltage is divided by the resistor R33, the diode bridge D31, and the capacitor C31.
Comparator 3
1 to detect whether the telephone line voltage is above or below the first predetermined voltage.
The output of the polarity storage circuit 4 is connected to the polarity storage circuit 4.

The polarity memory circuit 4 includes the telephone line connection terminals 1a, 1 connected to the input of the diode bridge 2.
A resistor R whose one end is connected to one side of b (1a side in Fig. 2)
41, a resistor R42 whose one end is connected to the other end of the resistor R41, and whose other end is connected to ground, the resistor R41, and the resistor R4.
A D-type flip-flop 41 has a data input terminal D connected to the connection point of the D-type flip-flop 41 and a clock input terminal CK connected to the output terminal of the comparator 31, which is the output of the voltage detection circuit 3. A resistor R43 whose one end is connected to the output terminal Q' and a resistor R43
A capacitor C41 has one end connected to the other end and the other end is connected to ground, one input terminal is connected to the output terminal Q of the D type flip-flop 41, and the other input terminal is connected to the resistor R43 and the capacitor C41. The output of the exclusive NOR 42 serves as a polarity change signal output terminal and is connected to the high voltage switch circuit 5.

In the high voltage switch circuit 5, the output terminal of the exclusive NOR 42 which is the output of the polarity memory circuit 4 is connected to the set input terminal S, and the output terminal of the terminal device 6 is connected to the reset input terminal R. The S-R latch 51 supplies the switch state signal to the terminal device 6 from its output terminal Q, and the resistor R5 is connected to the output terminal Q of the S-R latch 51.
A transistor Q51 whose base terminal is connected through 1 and whose emitter terminal is connected to ground, and a transistor Q5
A transistor Q52 serving as a high-voltage switch whose base terminal is connected to the collector terminal of 1 through a resistor R52, whose emitter terminal is connected to the positive output side end of the diode bridge 2, and whose collector terminal is connected to the terminal device 6. and a resistor R53 connected between the emitter terminal and base terminal of the transistor Q52. 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 1b rises from a low voltage to a first predetermined voltage or higher regardless of polarity, the polarity of this voltage is kept constant by the diode bridge 2. The voltage detection circuit 3 and the high voltage switch circuit 5 are supplied as a positive voltage. Then, this voltage is divided by the resistor R31 and the resistor R32 of the voltage detection circuit 3, and the divided voltage is applied to the capacitor C31 via the diode 31 and the resistor 33 (mainly the diode 31) connected in parallel. is charged at high speed and supplied to the non-inverting input terminal of the comparator 31. When the voltage at the non-inverting input terminal of the comparator 31 becomes equal to or higher than the voltage of the reference power supply 32 connected to the inverting input terminal of the comparator 31 due to the line voltage becoming higher than the first predetermined voltage, the output of the comparator 31 (voltage detection circuit 3
output) becomes 1 level and is applied to the clock input terminal CK of the D-type flip-flop 41 of the polarity storage circuit 4. The D type flip-flop 41 is configured so that the output signal of the voltage detection circuit 3 connected to the clock input terminal CK is 0.
It stores the 0 or 1 level state of the data input terminal D when the level changes from level to 1, and outputs a non-inverted level to the output terminal Q and an inverted level to the output terminal Q▲bar▼, as shown in Figure 2. As such, D type flip-flop 41
Since the data input terminal D of is connected to the telephone line connection terminal 1a through the resistor R41 and to GND through the resistor R42, the data input terminal D becomes 0 or 1 level depending on the polarity of the telephone line, and is a D type. Flip-flop 41 will store the polarity of the telephone line. If the polarity of the telephone line stored in this way is different from the previously stored polarity, the output terminal Q of the D-type flip-flop 41
and Q' were reversed from their previous states almost simultaneously, and the signal at the output terminal Q was quickly transmitted to one input terminal of the exclusive NOR 42, and the signal at the output terminal Q' charged and discharged the capacitor C41 via the resistor R43. Since it is transmitted as a signal to the other input terminal of the exclusive NOR 43 with a delay,
Both input terminals of the exclusive NOR 43 are at the same 0 or 1 level for a time determined by the time constant of the resistor R43 and the capacitor C41.
A 1-level polarity change signal is outputted to the output of the high-voltage switch circuit 5, and is applied to the set input terminal S of the S-R latch 51 of the high-voltage switch circuit 5.

S-R latch 51 of high voltage switch circuit 5
When the polarity change signal is applied from the polarity storage circuit 4 to the set input terminal S of the SR latch 51, the output terminal Q of the S-R latch 51 becomes 1 level, and is outputted to the terminal device 6 as a switch conduction state signal, and the resistor R51 is applied to the base terminal of transistor Q51 via
conduction. When the transistor Q51 becomes conductive, the resistor R53 is supplied with the voltage of the telephone line, which has been made positive by the diode bridge 2, through the resistor R52.
A current flows through the resistor R52 and R53, and the voltage at the base terminal of the transistor Q52, which is commonly connected to the resistors R52 and R53, decreases due to the voltage division between the resistors R52 and R53. A current flows from the emitter terminal to the base terminal of the transistor Q52, making the transistor Q52 conductive, and the voltage of the telephone line is output to the collector terminal of the transistor Q52, and is supplied to the terminal device 6.

The terminal device 6 is activated upon receiving a switch conduction state signal from the high-voltage switch circuit 5, starts a timer operation that operates for a predetermined period of time, and the high-voltage switch circuit 5
starts detecting the voltage of the telephone line supplied via the telephone line and the detection of the no-ringing incoming signal, and the voltage of the telephone line is lower than the first predetermined voltage or higher than the first predetermined voltage. A switch close signal is sent to the reset input terminal R of the S-R latch 51 of the high-voltage switch circuit 5 when the voltage exceeds the third predetermined voltage and when the no-ringing incoming signal cannot be detected within the predetermined time period during timer operation. Output.

S-R latch 51 of high voltage switch circuit 5
When the switch close signal is received at the reset input terminal, the output terminal Q becomes 0 level, the transistor Q51 becomes non-conductive, and the base current of the transistor Q52 is prevented from flowing, so that the transistor Q52 also becomes non-conductive.

In the network control device described above, when there is a call due to polarity reversal of the voltage of the telephone line and a no-ringing incoming call signal, the voltage of the output of the diode bridge 2 changes and changes from a low voltage to a first predetermined voltage. Since the line voltage rises above, the voltage detection circuit 3 detects the voltage and
The polarity memory circuit 4 operates to detect a change in polarity and turn on the high voltage switch circuit 5.
starts the terminal device 6 with a switch conduction state signal, the terminal device 6 starts timer operation, voltage detection, and no-ringing incoming signal detection operation, and the voltage of the telephone line is higher than the second predetermined voltage and lower than the third predetermined voltage. If a no-ringing incoming signal is detected while the timer is operating, the timer will stop and
Data communication processing can be performed.

Further, in the insulation test, when a voltage equal to or higher than the third predetermined voltage with polarity reversal is applied, the high voltage switch circuit 5 becomes conductive once, but due to voltage detection by the terminal device 6, A switch close signal is output from the terminal device 6, and the high voltage switch circuit 5 becomes non-conductive. Furthermore,
In the insulation test, if a voltage that does not cause polarity reversal or a voltage that is lower than the first predetermined voltage is applied, the polarity storage circuit 4 either outputs a polarity change signal or the voltage detection circuit 3
does not react, the high-voltage switch circuit 5 maintains a non-conducting state, and the direct current resistance of the line in the insulation test is the resistance R.
Is it more than the combined resistance value of 31 and R32, or resistor R31 and R32
is greater than the combined resistance value of R41 and R42.

Since the no-ringing incoming network control device is used by being connected in parallel with the telephone, when the 16Hz 75V signal of the telephone call signal is superimposed on the line voltage, polarity reversal occurs every 16Hz, but the voltage detection Diode D31, resistor R33, and capacitor C31 in circuit 3
Since the voltage detection circuit 3 continues to hold the voltage detection state, the polarity memory circuit 4 does not operate, and the voltage detection circuit 3 continues to hold the voltage detection state.
The high voltage switch circuit 5 does not become conductive for every Hz.

[0023]

[Effects of the Invention] As explained above, according to the present invention,
The voltage polarity of the telephone line is aligned in a certain direction with a diode bridge, and when the output voltage from the diode bridge having the polarity in the certain direction becomes equal to or higher than a first predetermined voltage, a detection signal is outputted in response to the immediate reaction, and this detection signal The polarity of the telephone line at the time when the voltage polarity of the telephone line is changed is memorized, and the switching means is made conductive by the polarity change signal outputted when the voltage polarity of the telephone line changes, and the output voltage of the diode bridge is supplied to the terminal device. This causes the terminal device to perform a telephone line voltage detection operation and a no-ringing incoming signal detection operation, and further shuts off the switch means by a closing signal outputted from the terminal device, thereby reducing the output voltage of the diode bridge to the terminal device. Since the supply is stopped, the telephone line can be connected regardless of the voltage polarity of the telephone line, making installation easier, eliminating the possibility of incorrect connections, and preventing the polarity of the telephone line from being swapped during other installation work. It is possible to accurately detect a call caused by a no-ringing call without any problem. Furthermore, it has a high impedance for insulation tests performed on telephone lines, does not interfere with insulation tests, does not respond erroneously to telephone ring signals, and operates accurately and with high reliability. can.

[Brief explanation of the drawing]

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.

FIG. 2 is a detailed circuit diagram of the no-ringing terminating network controller of FIG. 1;

FIG. 3 is a configuration diagram of a conventional no-ringing terminating network control device.

[Explanation of symbols]

1a, 1b Telephone line connection terminal 2 Diode bridge 3 Voltage detection circuit 4. Polarity memory circuit 5 High voltage switch circuit 6 Terminal device

Claims (1)

[Claims] 1. A no-ringing incoming network control device that is connected between a telephone line and a terminal device, is called by a no-ringing incoming signal from the exchange side, and connects the telephone line to the terminal device, the device controlling the voltage of the telephone line. A diode bridge connected between the telephone lines so that the polarities are aligned in a certain direction, and connected to the output of the diode bridge,
Voltage detection that responds promptly when the output voltage from the diode bridge changes to a first predetermined voltage or higher and outputs a detection signal, and responds with a delay when the output voltage drops below the first predetermined voltage. means, polarity storage means for storing the voltage polarity state of the telephone line when the voltage detection means outputs the detection signal, and outputting a polarity change signal when the voltage polarity of the telephone line changes; and the polarity change signal. conducts to supply the output voltage of the diode bridge to the terminal device, thereby causing the terminal device to perform a telephone line voltage detection operation and a no-ringing incoming signal detection operation, and a closing signal output from the terminal device. a switch means for stopping the supply of the output voltage of the diode bridge to the terminal device.