JPS61112467A - Erroneous start preventing circuit of network control unit - Google Patents

Abstract

PURPOSE:To make correct starting operation without giving influences on other terminal units by inserting the contact of a relay to prevent transmission of transmission signals to other terminals during data transmission. CONSTITUTION:When a terminal unit 111 or a telephone set 201 makes a call while a terminal unit 101 is transmitting data, energy accumulated in a capacitor 6 flows to a photocoupler 7 and makes output of a driving circuit 8 off. Conse quently, a relay 3 is restored and its contact is also restored and a DC loop is formed. On the other hand, as FS signals in data transmission of the terminal unit 101 are checked perfectly by a brake contact 11, the erroneous starting of the terminal unit 111 is not caused by this.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a false activation prevention circuit in a data transmission system using general subscriber telephones S, and in particular, in addition to one subscriber telephone MY telephone, two When the above terminal devices (including the M control unit) are shared for data transmission, it is possible to prevent the communication of one device from inducing the activation/operation of another device. This article relates to a circuit for preventing erroneous activation of network control equipment.

[Conventional technology]

In recent years, data on small leaves scattered over a wide area has been collected from the master station, such as automatic meter reading of water, gas, electricity, etc. used, monitoring of various electric power equipment, inspection of vending machine usage, etc. As a method for easily collecting data by activating slave stations in order, the next data transmission using a general subscriber telephone line (hereinafter referred to as a telephone line) is the most promising and is attracting attention.

When transmitting data using such telephone lines, it is no exaggeration to say that the terminal system determines the cost of the system, and in order to reduce the cost of this terminal system, the operating power supply It is not a good idea to use commercial power supply as a source, and the central office power source from the exchange is now used as is.

Furthermore, recently, public facsimile machines that use regular subscriber telephone lines have become popular for home use, and devices have been devised so that calls can be received by a special signal from a special facsimile communication network.

[Problem that the invention seeks to solve]

However, as mentioned above, when two terminal devices with automatic meter reading and automatic call receiving functions such as a public facsimile are connected together to a single telephone line, the data transmission signal of the terminal device causes This may cause the other device to start too slowly.

For example, if the activation condition is only a special single frequency signal other than 16Hz (or) (Russ) from the exchange side, then in the following case, the next frequency position pa< of the data communication of the other terminal device
A problem has arisen in that the single cylinder wave number component VL in the spectrum due to the shift, FS) signal becomes more concentrated than the single cylinder wave number component VL.

[Means for solving problems]

In view of the above points, the present invention has been made to solve such problems, and its purpose is to connect two terminal devices with automatic meter reading and automatic call receiving functions such as a public facsimile, or one telephone line. When connected, it is possible to perform correct startup 1gJ operations without affecting each other, and without preventing other data transmission operators from giving priority to making phone calls. , a multi-purpose, highly flexible communication system that shares one line with a telephone and at least two terminal devices. VC Ruru provides a circuit for preventing erroneous activation of a network control device.

In order to achieve this useful object, the present invention connects a first network control device IIA, a second network control device having superiority over the first network control device, and a telephone set in parallel with a general subscriber telephone line, The configuration is actuated by a starting signal sent from the first network control device, and the second network control device located at a lower level
A normally closed contact of a relay that is activated by the activation signal to open and close is inserted into one side of the communication path to the network control device, and this normally closed contact and the above general subscriber telephone line are connected in parallel so that the voltage between the connection points is The normally closed contact is inserted into a series circuit of a rectifier, a resistor, and a capacitor that are oriented to block the current when the current is in a steady state. + a photocoupler connected to the other side of the communication path, and the light emitting element side is connected in parallel in the opposite direction to the rectifier, and the output signal from the light receiving element side of this photocoupler changes from the first state to the second state. By changing to , the output becomes 1
A relay drive circuit that changes from one state to a second state, and a relay circuit that is energized when the output of the relay 410 circuit is in the first state and closes the normally closed contact. .

[For production]

When two terminal devices consisting of the first and second network control devices f each use a special single frequency signal as an activation condition, V
By inserting the normally-closed contact of a relay that blocks data transmission signals into the communication path to the lower-level terminal device, it is possible to prevent the lower-level terminal device from erroneous activation, and also to prevent the lower-level terminal device from erroneously starting up. When a device makes a call, the DC loop is detected (1) and acts on the off-hook detection circuit of the higher-level device, so as not to interfere with the calling operation of the lower-level device.

[Example〕 Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

The figure is a diagram showing an example of the false start prevention circuit of the network control device according to the present invention, and shows the basic circuit configuration of the false start prevention circuit and the connection with the terminal device.

In the figure, 14 shows a portion related to the false start prevention circuit according to the present invention, 101 is a first network control device, a higher-level terminal device (hereinafter referred to as a terminal device (Al)), and 111 is the first network control device. A second network control device with more superiority is Ruru lower terminal equipment R (hereinafter referred to as end floor equipment ω), 20
The telephone set shown in Figure 1 is connected in parallel to these RI telephone lines 20 and 21.

The terminal device IL(4) 101 is connected to the telephone line 20.2.
The system is configured to use the entire local power supply from the station 1 and to operate in response to reverse polarity and single object signals.

Next, during data communication, the telephone 20 connected in parallel with the terminal device (A) 101 at [5! 20, 21]
It is equipped with a function to detect off-hook situations such as 1, immediately stop data communication, and stop current consumption. In addition, 102
There is a bus for logically controlling the terminal device t(A)IQl.

In the false start prevention circuit 1, 2a and 2b are kojidoko iiMf
When t(A) 101 is excited, the terminal equipment (A) 101 receives the voltage as a starting signal only when the telephone S work 9 is excited, 2 is this terminal equipment fit(A) through this terminal 2a, 2b t- 1011C connected friend noise removal circuit 3
is excited by the output of the relay drive circuit (drive circuit) 8, and when the terminal device 1t(A) 101 is activated, the terminal device fI
This is a relay circuit that controls the normally closed contact (break contact) 11 that disconnects the line in order to prevent optical signals from flowing into the (L middle) 111. This break contact 11t is inserted into one side of the communication path to the lower terminal device &(B) 111. 4 is a rectifier (diode) oriented to block the current when the voltage at the connecting terminal TO, 711SJ5 is in a steady state, 5 is a resistor, and 6 is a diode 4. A capacitor intended for the purpose of being charged with telephone polarity in combination with a resistor 5, which are connected in series and connected to the telephone line 20, 21 through 11 break contacts in this series circuit 70, 71. 7 is a photocoupler which is connected in parallel with the diode 4 in the opposite direction and consists of an m light-emitting element and a light-receiving element that receives light from this light-emitting element;
This photocoupler T is the connection terminal 60, 61 or the terminal equipment @)
111 and telephone 201 in an I-current manner, and detects that the charges charged in the capacitor 6 form a DC loop. A photocoupler T detects the current in the drive circuit 8 and is configured to drive the relay circuit 3'1t only when the current is detected. Resistors 9 and 10 in a series circuit of resistors 10
n1 input terminal H is connected in parallel with the noise removal circuit 2, and the connection of the resistor 12 and capacitor 13 in the series circuit of the resistor 12 and capacitor 13 It is connected to a resistor 14 connected in parallel with the capacitor 13 and a light receiving element of the photocoupler 7, and is connected to a relay circuit 3 at its output end.

On the other hand, in the terminal device (3) 111, a single-frequency receiver (not shown) receives a single-frequency receiver from the telephone line 20.21 to 112! 113 is a DC blocking capacitor; 114 is a switch controlled by the control circuit 112 to form a DC termination with a resistor 115 for automatic response to incoming calls; 116 is a terminal device (A); ) 101 is not excited.
an off-hook detection circuit for detecting that a call has been made; 11
81': Current supply line from the power supply circuit 117 using C commercial power supply (CA Look), 80.81 is the telephone 201
The connecting terminals 90 and 91 are respectively connected to the connecting terminals 60 and 61 of the false start prevention circuit 1, and this connecting terminal 90 is connected to the control circuit 112 via the DC blocking capacitor 113 and also connected to the off-hook terminal. Detection circuit 1
16 to the connection terminal 80, and the connection terminal 91
is connected to the control circuit 112 and to the connection terminal a1. And this terminal equipment [[F]) 111
A telephone set 201 is connected to connection terminals 80 and 81 of.

Next, the operation of the case shown in figure C will be explained.

First, the terminal device (B) 111H1 operates using a commercial power source (AClooV)k from outside, and is designed to automatically start and operate incoming calls only when a single-phrase wave signal is received.

When the terminal device (a) 101 is in the data communication mode, the capacitor 6 is first charged with the potential from the telephone line 20.21, and then the break contact 11 is broken and the FS signal etc. during data communication is It works to prevent the data transmission signal from leaking to the terminal device (B) 111f[l+. Then, during data communication, the terminal device Q3) 11
1 When the telephone 201 forms a DC loop for making a call, the energy stored in the capacitor 6 flows through the light emitting element side of the photocoupler 7, and the photocoupler T
The light-receiving element side of is turned on, and accordingly, the output of the drive circuit 8 is set to t-0FF.

When the output of the drive circuit 8 turns OFF, the relay circuit 3
9, the pre-slip contact 11 is restored and closed, and a DC loop is formed between the telephone line 20, 21 and the terminal device 201.

When a DC loop is formed, an off-hook detection circuit (not shown) in the terminal device (AJlol) is activated, and finally the activation to the erroneous activation prevention circuit 1 is turned OFF.

Therefore, the break contact 11 is completely in the closed state, and does not interfere with the calling operation, communication/talk, etc. of the terminal device (B) 111 or the telephone set 201.

If we consider normal data communication, a frequency modulation (shift, FS) signal method is generally used, and this FS
The signal is a binary frequency modulated signal whose frequency is shifted to logic 11" or logic sO", and its spectrum is determined by the shift ratio, that is, the ratio of the frequency shift between marks and spaces to the dot frequency. be done.

Here, the dot frequency is determined by the communication speed and the logical %1' or logical %0'' pattern component.

(For details, see "Data Transmission," published by Lattice, translated by Shogo Seri.) Such a spectrum appears as various same wave number components depending on the code being communicated, with varying levels, and depending on the activation conditions of the terminal device, it becomes a single frequency component. , leading to the terminal device erroneously starting up.

In the present invention, in order to prevent false activation due to the spectrum of the FS signal during data overload, the lower terminal equipment f(
A break contact 11 is inserted into the communication line to which the terminal device (B) 111) is connected, that is, a circuit for blocking data transmission AC signals is inserted.

Furthermore, while the terminal device (A) 101 is in data communication, that is, the break contact 11 is broken, the terminal device (E) 111 with a high priority or a telephone! 201 is detected, and furthermore, a complete DC loop is formed from the terminal device (8) 111 or telephone 201 to the telephone line, and by using the off-hook detection function of the terminal device (4) 101, the self-activation is completely completed. I am canceling it.

In addition, in the above description, the terminal device (A) 101
was explained using the case of using the local power supply as an example, but the misfire F
! A is not limited to this.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to realize a multipurpose and highly reliable communication system in which all telephones on one subscriber telephone line and at least two terminal devices share the same, and
For example, when two terminal devices with automatic meter reading and automatic call receiving functions, such as a public facsimile, are connected to two telephone lines, each can perform the correct startup operation without affecting the other, and the telephone Since there is no hindrance to giving priority to calls made over other data transmissions, the practical effect is extremely significant.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an erroneous activation prevention circuit for a network control device according to the present invention. 1... Erroneous startup prevention circuit, 3... Relay circuit, 4
...Diode (rectifier), 5...Resistance, 6.
...Capacitor, 7...Photocoupler, 8.Φ drive circuit (relay drive circuit), 11...Break contact (normally closed sharp button, 20.21...Telephone line, 10
1...Terminal device (A) (first network control device &),
111...Terminal device a3) (second network control device, 201...Telephone.

Claims (1)

[Claims] A first network control device and this first network control device are connected in parallel with the general subscriber telephone line.
A second network control device having superiority over the network control device and a telephone set are connected, and the second network control device, which is located at a lower level, is activated by a start signal sent from the first network control device. inserting a normally closed contact of a relay that is activated and opened by the activation signal into one of the communication paths to the network control device;
The normally closed contact is inserted into a series circuit of a rectifier, a resistor, and a capacitor oriented to block current when the voltage between this normally closed contact and a connection point connected in parallel to the general subscriber telephone line is in a steady state. A photocoupler connected between the other side of the communication path and having a light emitting element side connected in parallel in the opposite direction to the rectifier, and an output signal from the light receiving element side of this photocoupler changing from a first state to a second state. a relay drive circuit whose output changes from a first state to a second state; and a relay circuit which is energized to open the normally closed contact when the output of the relay drive circuit is in the first state. A circuit for preventing erroneous activation of a network control device, characterized by: