JPH0310558A - Network controller - Google Patents

Abstract

PURPOSE:To detect the busy state of a telephone line for a call with simple circuit constitution by starting a no ringing incoming call detection circuit, supplying a voltage signal fed to the telephone line to the no ringing incoming call detection circuit thereby detecting the state of the telephone line. CONSTITUTION:A dialing line connection communication block 13 applies a voltage to a detection circuit 11 via a terminal call start diode 212 to check the voltage. The line voltage at that time is fed to a low voltage detection Zener diode 211 and a high voltage detection Zener diode 27 so as to identify whether or not the line voltage is within a voltage decided by both the Zener diodes, that is, within a range of nearly 36-60V. When the line voltage is within 36-60V, a no ringing communication block 14 gives a signal to the dialing line connection communication block 13 via a line state output line 12. As a result, the call line connection communication block 13 identifies it that the telephone line is not busy.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Application Field) The present invention has a no-ringing incoming call detection circuit that is connected to a telephone line and detects no-ringing incoming calls, and utilizes the no-ringing incoming call detection circuit. The present invention relates to a "network a" control device that detects the state of a telephone line for making a call.

(Prior Art) This type of network control device connects a terminal device that reads water, gas, electricity, etc. meters to a distant data collection center device via a telephone line, and receives no-ringing calls from the data collection center device. This telephone line is used for data collection systems, etc., which receive calls to the terminal device via the network control device and collect 81 measurement data from the terminal device. are generally connected in parallel, and in such a case, a call may be made from another device such as this telephone to the telephone line. When making this call, it is necessary to confirm that the telephone line is not in use, so the network controller has a function to detect the usage status of the telephone line in addition to the function of detecting no-ringing incoming calls. .

FIG. 2 is a circuit diagram of a conventional network control I device having both of these functions. This conventional organization O device connects telephone lines L1. No-ringing incoming call detection circuit 3 connected to L2
2, a terminal calling line in use detection circuit 31
A no-ringing communication block 33 is connected to the subsequent stage of the no-ringing incoming call detection circuit 32, and a calling line connection communication block is connected between the terminal calling line in use detection circuit 31 and the no-ringing incoming call detection circuit 32. 34
are connected, and terminals T1. Other equipment such as a telephone (not shown) is connected via T2.

The no-ringing incoming call detection circuit 32 has a polarity detection diode 41 connected in series to the telephone line L2, and when a positive voltage is applied to the telephone line L2 due to a no-ringing incoming call, this polarity detection diode 41 becomes conductive. death,
The switching transistor 4 via the diode 41
A positive voltage is applied to the collector and base of No. 3. As a result, the switching transistor 43 turns on,
The first two positive polarity voltages are applied to the other switching transistor 47 connected in series to the switching transistor 43.
is applied to both ends of the Zener diode 44 for low voltage detection via the emitter base of the Zener diode 4.
The switching transistor 47 is made conductive via the transistor 4. These switching transistors 43.
47 becomes conductive, the no-ringing communication block 33 connected to the collector of the switching transistor 47 is connected to the telephone lines Ll, L2 via these conductive switching transistors, and the no-ringing communication block 33 is thereby connected. A CPU fi control block (not shown) connected via line 35 is activated, and CPU control for data transmission is started.

In addition to the above-mentioned no-ringing incoming call detection function, the no-ringing incoming call detection circuit 32 also detects when a high voltage signal is applied to the telephone line L2 for an insulation test of the telephone line.
When a 16 Hz, 75 VAC ringing signal is applied, these signals are passed through the switching transistors 43 and 47 to the no-ringing communication block 33.
A Zener diode 42 for detecting a high voltage is made conductive so that the signal "C" is not applied to the control circuit connected to the base circuit of the switching transistor 43 when the Zener diode 42 is made conductive by the signal. The transistor 46 is turned on, so that the switching transistor 43 is not conductive.

On the other hand, the terminal calling line in-use detection circuit 31 has two photocouplers 51 and 52 connected in series to the telephone line L1 in opposite directions to each other, and these photocouplers connect the telephone terminal fi! 11 is detected, and the current flowing through the terminal T1. In addition to detecting whether a device such as a telephone connected to T2 is in use or not,
A photocoupler 53 for detecting the calling signal of A075V is connected between the telephone lines L1 and 12 via a DC cutoff capacitor or the like, thereby detecting the application of the calling signal. If it is determined that the telephone line is being used as described above, or that the @trusted calling signal is applied to the telephone line and the telephone line is being used, it will stop making calls and stop the telephone line from being used. If it is determined that there is no such device, a call operation is performed.

<Problems to be Solved by the Invention> The conventional network control I device described above has a dedicated terminal call line in-use detection circuit 31, and two detection circuits are provided in addition to the no-ringing incoming call detection circuit 32. Therefore, there are problems in that the circuit configuration is complicated and uneconomical.

The present invention has been made in view of the above, and its purpose is to provide a no-ringing incoming call detection circuit and a network control feature that can detect when a line is in use with a simple and economical circuit configuration. There is a particular thing.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the network control device of the present invention is connected to a telephone line, has a no-ringing incoming call detection circuit, and has a no-ringing incoming call detection circuit. A network control device a for detecting the state of a telephone line, comprising a starting means for starting the no-ringing incoming call detection circuit, and a voltage signal supplied to the telephone line by the no-ringing incoming call detecting circuit started by the starting means. The present invention further comprises a supply means for supplying a voltage signal supplied to the telephone line to the no-ringing incoming call detection circuit in order to detect the state of the telephone line.

(Function) The network side til device of the present invention activates the no-ringing incoming call detection circuit, supplies the voltage signal supplied to the telephone line to the no-ringing incoming call detection circuit, and thereby detects the state of the telephone circuit.

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

FIG. 1 is a circuit diagram of a network control device according to an embodiment of the present invention. The network control device shown in the figure includes telephone lines Ll, L, 2.
A no-ringing communication block 14 is connected through the detection circuit 11, and a calling line connection communication block 13 is connected to the telephone lines L1 and L2. The no-ringing communication block 14 and the calling line connection communication block 13 are connected to a CPU control block (not shown) via a connection line 15, and data transmission is performed under the control of the CPU control and IJ control. . Further, the telephone line 11.12 is connected to the terminal T1. It is connected to other equipment such as a telephone (not shown) via T2.

The detection circuit 11 has a no-ringing incoming call detection function and a circuit usage state detection function.

More specifically, the detection circuit 11 is based on a conventional no-ringing incoming call detection circuit, and has a circuit use state detection function added to the no-ringing incoming call detection circuit.

The detection circuit 11 has a rectifying diode bridge 21 connected between the telephone lines [1 and 12, and the output of the rectifying diode bridge 21 is connected to a high voltage detection Zener diode 27 and a switching transistor 26,
The rectifying diode bridge 21 connects the telephone line Ll,
With the polarity of the voltage applied to L2 aligned, the Zener diode 27 for high voltage detection and the switching transistor 2
6. In addition, the switching transistor 2
6 is a switching transistor 260 connected in series.
It is connected to the no-ringing communication block 14 via. The base of the switching transistor 260 is connected to ground via a low voltage detection tuner diode 211. J3, switching transistor 26
The base of is a resistor and switching control transistor 2
5 to ground.

A high voltage detection Zener diode 27 connected to the output of the rectifying diode bridge 21 is connected to the base of a high voltage control transistor 28 via a resistor. The collector of the high voltage υ1 transistor 28 is supplied with voltage 1 through a resistor, and the emitter of the high voltage control transistor 28 is connected to the base of an off control transistor 29. A calling signal detection capacitor 210 is connected between the bases of the two off-control transistors and the ground,
A resistor is connected in parallel to the calling signal detection capacitor 210.

On the other hand, the detection circuit 11 has a polarity detection diode 22 connected to the telephone line 2 via a resistor, and detects a positive voltage applied to the telephone line 2 by the polarity detection diode 22. It is designed to be detected. The cathode of the polarity detection diode 22 is a polarity control transistor 23.
1 & is connected to the base of the terminal, and is also connected to the calling line connection communication block 13 via the activation diode 212 for terminal calling. The polarity control transistor 23 has a collector supplied with voltage V- via a resistor, and an emitter connected to the base of a switching control transistor 25 via a switching off transistor 24. The base of the switching-off transistor 24 is connected to the collector of the off-control transistor 29 . Further, the collector of the off control transistor 29 is connected to the base of another transistor 290 via a resistor, the emitter of this transistor 290 is connected to the emitter of the polarity control transistor 23 via a resistor, and the collector is connected to the base of another transistor 290 via a resistor. The circuit configuration is such that it is connected to the base of the transistor 29, so that positive feedback is applied.

The network control device of the present invention is configured as described above. Next, the effect will be explained.

Note that in the telephone exchange, telephone line L1. When L2 is not in use, telephone line L1 is at +48 volts.
The voltage between 1 and 12 is between 1 volt and 36 volts with undefined polarity. When another no-ringing terminating device is communicating, the line voltage is approximately 30 volts with telephone line L1 having a negative polarity. When a ringing signal is being applied for receiving a call, the telephone line L1 is biased to 48 volts of negative polarity, and a ringing signal of 16H2, ΔC75V is applied intermittently with 1 second on and 2 seconds off. The detection circuit 11 detects a no-ringing incoming voltage from 36 volts to about 60 volts through the low voltage detection Zener diode 211 and the high voltage detection Zener diode 2, respectively.
7 was detected.

First, a case where there is a no-ringing incoming call will be described. No-ringing calls are received on telephone line L1. L2
The polarity of is reversed, and a positive voltage is applied to the telephone line L2. Therefore, when there is a no-ringing incoming call, a forward incoming voltage is applied to the polarity detection diode 22 connected to the telephone line L2, and the incoming voltage is supplied to the polarity control transistor 23 via the polarity detection diode 22. and the polarity control transistor 23 is turned on.

When the potential control transistor 23 is turned on, the telephone line L
The voltage from 2 is applied via the polarity detection diode 22 and the polarity control transistor 23 to the collector and base of the switching-off transistor 24 via the resistor, and the switching-off transistor 24 is turned on.

When the switching-off transistor 24 is turned on, a voltage is applied to the base of the switching transistor 25 via the switching-off transistor 24, and the switching control transistor 25 is also turned on. A base current flows through, and the switching transistor 26 is turned on. When the switching transistor 26 is turned on, the incoming voltage applied to the telephone line L2 passes through the rectifying diode bridge 21 and the switching transistor 26 to the base of the switching transistor 260 and the low voltage detection Zener diode 2.
It is supplied between 11 and 11. As a result, the incoming voltage applied from the telephone line L2 is detected by the low voltage detection Zener diode 211.
When the Zener voltage becomes higher than the Zener voltage of the switching transistor 260, the switching transistor 260 is turned on.
The incoming voltage is passed through the no-ringing communication block 1 through 60.
4, the connection with the telephone line is completed, and the no-ringing communication block 14 becomes operational. Note that under normal conditions, the telephone line L1 is of positive polarity, and the telephone line L2 is of positive polarity.
is negative polarity, the polarity detection diode 22 is reverse biased, and the switching transistors 26, 260 are in the off state, so the no-ringing communication block [1 to 1
4 is no longer working.

By the way, the transmission voltage applied to the telephone line L2 when a no-ringing call is received is supplied to the polarity detection diode 22 as described above, and at the same time, it is also supplied to the high voltage detection Zener diode 27 via the rectification diode bridge 21. However, since the Zener voltage of the Zener diode 27 for high voltage detection is higher than the no-ringing incoming voltage, the Zener diode 27 for 8-voltage detection does not conduct, and the circuit following the Zener diode 27 for high voltage detection also does not operate. ing.

In addition, telephone line L1. A high voltage may be applied to the telephone line L2 for the insulation test of L2, but since this is different from a no-ringing incoming call, it is desirable that the no-ringing communication block 14 not operate. Therefore, in this case, the high voltage applied to the telephone line L2 is supplied to the polarity control transistor 23 via the polarity detection diode 22, and at the same time is supplied to the high voltage detection Zener diode 27 via the rectification diode bridge 21. However, the high voltage for this insulation test is connected to the Zener diode 2 for high voltage detection.
Since the Zener voltage is higher than the Zener voltage of No. 7, the high voltage detection Zener diode 27 becomes conductive. As a result, when the Zener diode 27 for high voltage detection becomes conductive, the voltage control transistor 28 is turned on, which also turns on the off control transistor 29. As the off control transistor 29 turns on, the switching off transistor 2
Since the base of the switching off transistor 24 is suppressed to the ground level to prevent the switching off transistor 24 from turning on, even if the switching off transistor 24 tries to turn on via the previous JL path, it will not be able to turn on. Since the switching-off transistor 24 cannot be turned on, the switching control transistor 25 cannot be turned on either. Therefore, the switching transistor 26.260
cannot be turned on, so the no-ringing communication block 14 cannot operate.

Furthermore, the no-ringing communication block 14 must not operate even when a 16Hz, AC75V (7) call signal is applied; The Zener diode 27 for high voltage detection becomes conductive at the peak of the calling signal, and as a result, the high voltage control transistor 28 and the off control transistor 29 are turned on. However, the Zener diode 27 for high voltage detection becomes non-conductive at the valley part of the calling signal, and as a result, the off control transistor 19 also tries to turn off. capacitor 21
OFF control transistor 2 due to charge accumulated in 0
9 does not turn off even at the valley of the ringing signal, and remains on while the ringing signal is applied. Therefore,
As a result, the switching-off transistor 24 cannot be turned on, and as a result, the switching transistors 26 and 260 also remain off, so that the no-ringing communication block 14 does not operate.

On the other hand, in order for the network control device 11 to make a call, it must detect the usage status of the line. First, if a no-ringing call is being received, the no-ringing communication block 14 sends the call via the line status output line 12. Since the line in use signal is supplied to the line connection communication block 13, it is determined that the line is in use, and the calling operation is stopped at the discretion of the CPU control block.

Therefore, it is only necessary to check the case where the telephone line L1 other than the above has positive polarity.
2, a voltage is applied to the detection circuit 11 to start it up and check it. In other words, the calling line connection communication block 1
3 applies a starting voltage to the detection circuit 11 via the starting diode 212 for terminal calling, the starting voltage turns on the polarity control transistor 23, which turns on the switching off transistor 24 and As the switching 11111 transistor 25 tries to turn on, the line voltage being supplied to the telephone line L1 at this time is supplied to the high voltage detection Zener diode 27 via the rectifying diode bridge 21, and the switching transistor 26.260
is supplied to the Zener diode 211 for low voltage detection. As a result, the line voltage at this time is supplied to the low voltage detection Zener diode 211 and the high voltage detection Zener diode 27, and the line voltage is within the voltage range determined by both Zener diodes, that is, approximately 36 to 60 volts. It is determined whether there is one or not. That is, when the line voltage is within this voltage range of 36 to 60 volts, the low voltage detection Zener diode 211 conducts, thereby turning on the switching transistor 260, and the line voltage is passed through the switching transistor 26°260. Since the signal is supplied to the no-ringing communication block 14, the no-ringing communication block 14 supplies a signal to the calling line connection communication block 13 via the line status output line 12. As a result, the calling line connection communication block 13 can identify that the telephone line is not in use, and can thereby seize the line and perform communication.

(Effects of the Invention) As explained above, according to the present invention, the no-ringing incoming call detection circuit is activated, the voltage signal being supplied to the telephone line is supplied to the no-ringing incoming call detection circuit, and the state of the telephone line is thereby detected. Since the no-ringing incoming call detection circuit can be used to detect the state of use of the telephone line for making a call, the circuit configuration can be simplified and cost-effective.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a network control I device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional network control device. DESCRIPTION OF SYMBOLS 11... Detection circuit, 13... Line connection communication block for calling, 14... No-ringing communication block, 21... Diode bridge for rectification, 24... Switching off transistor, 25... Switching control transistor, 26.2
60...Switching transistor, 27...Tsj node diode for high voltage detection, 29...Off control transistor, 210...Capacitor 4J for calling signal detection, 211
...Zener diode for low voltage detection, 212...Starting diode for terminal calling, Ll, L2...Telephone line.

Claims (1)

[Claims] A network control device connected to a telephone line, having a no-ringing incoming call detection circuit, and detecting the state of the telephone line for making a call, comprising: activation means for activating the no-ringing incoming call detection circuit; and activation means for activating the no-ringing incoming call detection circuit. supplying the voltage signal supplied to the telephone line to the no-ringing incoming call detection circuit in order to detect the voltage signal supplied to the telephone line by the no-ringing incoming call detection circuit and detect the state of the telephone line; A network control device comprising means.