JPS5821469B2 - network control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides connection control and power supply for data terminal devices (hereinafter referred to as data terminals) using a power supply on the exchange side in a data collection system that uses subscriber telephone lines (hereinafter referred to as telephone lines). The present invention relates to a network control device.

It is being considered to install a data terminal on the subscriber side of a telephone line and collect data from automatic meter readings of electricity, gas, water, etc. into a solid device.

For this type of data collection, prioritize the use of the telephone above all else, and even if data collection is in progress, if there is an incoming or outgoing phone call, data collection will be stopped, and the terminal will not be called for data collection. I also try to do this without ringing my phone.

Generally, exchanges and telephones are connected as shown in FIG.

In this configuration, 1 is the exchange side, 2 is the subscriber circuit, and 3 is the subscriber circuit.
, 4 is the incoming trunk, 5 is the 16Hz bell signal oscillator,
6 is a 48V DC power supply, 7 is a telephone line, and 8 is a telephone set, and a data terminal 9 is connected in parallel with the telephone set 8.

In normal times, the subscriber circuit 2 is connected to the earth - 948V - IJ Shire I,) Winding - Contact C1 - Terminal a - Telephone line 7 - Terminal L2 - Telephone 8 - Terminal L1 - Telephone line 7 - Terminal 1 - Contact C2 - The circuit is configured with the ground air route, and -48V appears at the terminal L2tL+ on the telephone side, but since the telephone 8 is in the on-hook state, no loop current flows.

If the telephone goes off-hook in this state, the DC circuit is closed and a loop current flows, and the loop current is detected by relay L. As a result, the telephone line 7 is connected to a calling register (not shown), and the dial information reception operation is started. It is done.

A loop current is supplied from relay A from the time the dial information is received until the end of the call.

When the other party answers, the polarity of the telephone line 7 is reversed.

In the case of an incoming call, the telephone line 7 is connected from the subscriber circuit 2 to the outgoing side of the incoming trunk 4, and a 16 Hz ringing signal is sent to the ground.
Oscillator 5 - Relay winding F - Contact g.

One terminal low telephone line 7 one terminal L2 - telephone 8 one terminal L1
- Telephone line 7 one terminal one contact g1 - resistance r -948V
- It is sent out through the earth route, and terminals a and b have e in normal condition.
A signal is generated in which $48V, which has the opposite polarity to 48V, is superimposed with a 16 Hz ringing signal.

Furthermore, when the telephone 8 rings and the subscriber answers, a loop current flows through the relay winding F, and the relay G (not shown) flows through the relay winding F.
is operating and contact g.

, the calling circuit is disconnected by Σg1 (ring trip)
, the loop current flows through the relay winding to form a communication path with the other subscriber, and the communication path is maintained until the end of the call.

Terminal a when the ring is tripped. The voltage polarity of b returns to its original state.

In reality, as shown in Figure 2, the frame L is
Signals are exchanged with subscribers via the LF.

As a data collection system, incoming call trunk I for telephones is used.
A special track SPT for data collection separate from the CT is provided, and a network control device NCUIO is also provided between the telephone 8 and the data terminal 9 via the frame LLF.

In this configuration, in the case of a telephone call, the connection is made via the incoming trunk ICT-frame LLF route as described above, and at the moment of the incoming call, the polarity of the telephone line 7 is reversed, and the 16Hz call signal is transmitted via the network controller NCUIO. and ring the bell on telephone 8.

On the other hand, in the case of a call to data terminal 9, special trunk 5PT
-Connected via the route of frame LLF, 16 after polarity reversal
A call is made using a signal system other than Hz that does not ring the telephone 8, and the network control unit NCU 10 detects this and activates the data terminal 9 to collect data.

By the way, it has been considered in the past for the network control unit NCU 10 to drive data terminals by using the power source of the station (exchange side) without having its own power source.

Therefore, as a means of using the local power supply, a diode magnet is interposed in the part where the DC loop is formed, and the directionality of this diode is used to prevent power from being supplied to the data terminal during normal times when data is not being collected. A method has been considered in which the DC circuit is closed through a diode only when the polarity is reversed to supply current to the data terminal.

However, with this method of supplying current by simply closing the DC circuit when the polarity is reversed, the diode becomes conductive even when the polarity is reversed during a normal telephone call or outgoing call, and the DC circuit is closed. However, there were inherent problems that hindered the normal operation of the telephone.

In addition, polarity reversal is also performed in line tests, but there is also the problem that correct tests cannot be performed.

On the other hand, a method can be considered in which a call is made using a signal having a frequency other than 16 Hz after the polarity is reversed, and after this signal is detected, the DC circuit is immediately closed to supply current to the data terminal.

According to this system, even when the polarity is reversed, the DC circuit is not closed unless the above-mentioned calling signal is detected, so that the above-mentioned problem is temporarily resolved.

However, if the above-mentioned ringing signal transmission level cannot be made higher than the speech level, for example, in a ringing signal system that uses a frequency within the speech band as the calling signal, this signal level is kept low, and therefore it is necessary for detection. A detection circuit with an amplification function is required.

Therefore, an operating power supply is usually required, but
In order to utilize the local power supply, it is strongly desired that the above-mentioned normal operation of the telephone set and line test be not affected.

The present invention has been made with these points in mind, and it detects a specific ringing signal by flowing a current that is less than the non-sensing value of the relay of the exchange at the time of polarity reversal, and
The purpose of the present invention is to provide a network control device that can utilize the local power source without adversely affecting the original operation of the telephone line by stopping the consumption of this detection current after a certain period of time has elapsed since the polarity reversal.

The present invention will be described in detail below with reference to the drawings, but before describing embodiments, a basic configuration including an auxiliary power supply circuit and a calling signal detection circuit will be described.

In FIG. 3, 11 is a telephone, 12 is an off-hook detection circuit that detects off-hook of the telephone 11, and 13 is a switching circuit that becomes conductive when the polarity is reversed, becomes non-conductive due to the detection output of the off-hook detection circuit 12, and disconnects the subsequent circuit. ,
Reference numeral 14 denotes a terminal call detection unit 17, which is composed of a call signal detection circuit 15 that detects a specific call signal guided through the switching circuit 13, and an auxiliary power supply circuit 16 that supplies its operating power.
is a connection circuit consisting of a switching element that closes a DC circuit according to the output of the terminal call detection section 14.

When the connection circuit 17 is on, a predetermined current is supplied to a data terminal (not shown) through the terminal T, and signals are exchanged between the data terminal and the exchange through the office line connected to the terminal.

Next, the operation will be explained with reference to the operation waveform diagram in FIG.

First, the polarity a of the telephone line is L2Q, L. In the case (2), that is, in the normal state, the switching circuit 13 is non-conductive, and there is no current consumption in this network control device, and the consumption current d does not flow.

Next, when a call is made to collect data through the exchange, the polarity a is reversed to L2, Lle, and the switching circuit 13 becomes conductive.

Then, the auxiliary power supply circuit 16 rectifies the current from the station and supplies an operating current to the calling signal detection circuit 15.

in this case,. The current consumption d is limited to a current (1) that is less than the insensitive value of the relay that detects the loop current in the exchange, and the exchange does not perform any incoming call detection operation.

The current supply from the auxiliary power supply circuit 16 causes the calling signal detection circuit 15 to be activated.

In this state, when a calling signal of a specific frequency is sent from the exchange, this is detected by the calling signal detection circuit 15,
When both the polarity inversion state and the calling signal continue for a certain period of time or more, a detection output is generated, and in response to this detection output, the connection circuit 1
7 starts.

As a result, the telephone line and the terminal T of the data terminal are connected via the switching circuit 13 and the connection circuit 17, and a predetermined current is supplied to the data terminal.

In this case, the current consumption d is set so that a current (2) exceeding the emotional value of the relay of the exchange flows, thereby enabling the exchange to detect an incoming call.

Upon detecting this incoming call, the exchange sets up a communication path (in this case, a data transmission path) between the solid equipment and the terminal equipment.

When the data terminal is activated by the current supply, it generates a signal based on the data to be collected.

This data signal C is sent to the exchange side.

When the communication is completed in this way, the exchange returns the polarity a of the telephone line to its original state.

During the above operation, if the polarity a of the telephone line is inverted and the ringing signal is not detected, or if one of the two does not continue for a certain period of time, the output of the ringing signal detection circuit 15 is generated. Therefore, the connection circuit 17 is not activated and there is no closure 0 of the DC circuit.

Furthermore, when subscriber telephone set 11 goes off-hook during the above operation (during data transmission), off-hook detection circuit 12 detects this, and its output turns off switching circuit 13 to disconnect the data terminal.

5. This network control device performs a terminal call detection operation by passing a current that is less than the non-sensing value of the relay of the exchange when the polarity of the telephone line is reversed. This eliminates the need for a special power source for ring signal detection.

FIG. 5 shows an embodiment of the present invention, in which, in contrast to the basic configuration shown in FIG. 3, a time-limiting circuit 1 cuts off the supply current of the auxiliary power supply circuit 16 to a disconnected state after a certain period of time has passed since the polarity is reversed.
This is a configuration with 9 added.

Note that 18 is a polarity reversal detection circuit that operates when the voltage exceeds a predetermined value during polarity reversal.

The operation will now be described with reference to the waveform diagram in FIG.

6a, b, c, and d show the voltage at terminal L2 of the telephone line divided into various operating states.

First, in the case of normal data collection, the switching circuit 13 is made conductive by reversing the polarity, and as shown in FIG.
When a calling signal (other than 6 Hz) is superimposed and a minute current flows, the voltage becomes slightly lower than +48■.

At the time of response, the DC circuit is closed due to conduction of the connection 1 circuit 17, and current is supplied to the data terminal, so that the terminal voltage further decreases to a predetermined value.

Furthermore, when the data signal from the data terminal is sent out,
A data signal is superimposed on this voltage.

A.By the way, for phone line capacity tests,
Alternatively, a line test is performed as necessary.

In this case, there is no special signal and only polarity inversion is performed as shown in FIG.

Since a small current flows at this time, the terminal voltage is +48V.
decreases slightly from

However, at this time, upon receiving the output of the polarity reversal detection circuit 18, the timer circuit 19 starts operating and disconnects the auxiliary power supply circuit 16 after a certain period of time from the polarity reversal.

Therefore, at this point, the terminal voltage returns to +48V of the local power supply.

Therefore, even if there is a line test, there will be no particular impact.

In the case of an incoming telephone call, a 16 Hz ringing signal is superimposed after the polarity is reversed as shown in FIG. 6C.

Due to the polarity reversal, a small current flows and the terminal voltage drops slightly, but as in the case of FIG. 6, the small current is cut off after a certain period of time by the timer circuit 22, so it does not affect the telephone.

Furthermore, in the case of making a telephone call, as shown in Figure 6 d, after off-hook, during dialing and connection, the polarity is L1■t.
Since it is L2 e, the switching circuit 13 is off and the network control circuit has no effect on the operation of the telephone.

Next, when the called party responds and enters a talking state, the calling party enters a polarity inversion state.

However, since the direct current circuit is closed by the telephone 11, the off-hook detection circuit 12 operates, and its output turns the switching circuit 13 into an OFF state, so that there is no problem with the telephone call.

As described above, in the embodiment shown in FIG. 5, the polarity reversal detection circuit 18 ensures the detection of polarity reversal, and the time limit circuit 19 stops the minute current after a certain period of time after the polarity reversal, and the terminal voltage is brought to a steady value. Since the line test is restored, the line test can be carried out without any trouble, and it will not be affected by the line test, nor will it have the same effect on incoming calls.

As described above, according to the present invention, when the polarity is reversed, a current that is lower than the relay value of the exchange is caused to call a terminal for data collection, and when a response is made, current is supplied to the data terminal, and the exchange Since the structure is configured so that the DC circuit is closed by passing a current higher than the relay's sensing value, it is possible to supply operating power before the DC circuit is closed, and the time-limited circuit allows the DC circuit to be closed. Since even the consumption is limited to a certain period of time, it is possible to provide a network control device that does not adversely affect the normal operation of telephones or line tests.

[Brief explanation of the drawings] Figure 1 is a block diagram showing the relationship between the trunk circuit of a general telephone exchange and telephones, Figure 2 is a system diagram showing the relay method of a conventional data collection system, and Figure 3 is a diagram of the main A configuration diagram for explaining the invention, FIG. 4 is an operation waveform diagram of the device in FIG. 3, and FIG.
The figure is a configuration diagram showing a network control device according to an embodiment of the present invention.
Figure 6a, b. c and d are waveform diagrams showing changes in terminal voltage due to various operations of the network control device shown in FIG. 5; 11...Telephone, 12...Off-hook detection circuit, 13...Switching circuit, 14...
・Terminal call detection unit, 15... Call signal detection unit,
16... Auxiliary power supply circuit, 17... Connection circuit, 18... Polarity reversal detection circuit, 19...
...Timed circuit.

Claims (1)

[Claims] 1. A system installed between a subscriber telephone line connected to an exchange and a data terminal equipment, which supplies power from the exchange to the data terminal equipment in response to a specific ringing signal that does not ring the telephone bell, and also outputs the data terminal equipment. A network control device that guides signals to the exchange side includes means for keeping the signal disconnected from the exchange side during normal times, a ring signal detection circuit for detecting the specific ring signal, and a relay of the exchange when the polarity of the subscriber telephone line is reversed. an auxiliary power supply circuit that supplies a current below a dead value to the calling signal detection circuit for its operation; a time limit circuit that cuts off the supply current of the auxiliary power supply circuit after a predetermined period of time has elapsed since the polarity reversal of the subscriber telephone line; 1. A network control device comprising: means for supplying a current greater than the sensing value of a relay of an exchange to a data terminal device in order to close a DC circuit in response to a detection output of a calling signal detection circuit.