JPS60213163A - Sixteen-hz treating circuit of network control device - Google Patents

Abstract

PURPOSE:To prevent a telephone line from being influenced with a 16-Hz signal flowed into a power supply circuit by starting a subscriber's telephone line by a specific starting signal, after a prescribed delay time, connecting the subscriber's telephone line to the power supply circuit. CONSTITUTION:A switch circuit 1 is connected to the subscriber's telephone line 10. When a starting signal having specific polarity is inputted, the subscriber's telephone line 10 is turned on. A timer circuit 2 delays the turning on of the switch circuit 1 until a fixed period is passed after turning on the polarity of the telephone line 10. When the circuit 2 generates a timer output 20, the circuit 1 is controlled so as to be turned on, and the power supply circuit 3 supplies electric power to data terminal not shown.

Description

Detailed description of the invention: Technical field to which the invention pertains The present invention relates to a data transmission system using a general subscriber telephone line, which is connected between a data terminal and a subscriber line, and is applied only when activated by an activation signal. The present invention relates to a network control device for connecting a data terminal to a subscriber line, and particularly relates to an improvement that does not adversely affect a 16 Hz paging signal.

Conventional technology In recent years, automatic meter reading for measuring usage of water, gas, electricity, etc., or monitoring of various electric power equipment, etc. has become popular.

As a method to easily collect information scattered over a wide area, such as when surveying the usage of vending machines, data terminal equipment is connected to the subscriber line, and each data terminal is activated in turn from the master station. A data collection system that transmits data from a data terminal to a subscriber telephone line is attracting attention because of its effectiveness. Such systems have a very wide range of application fields and are highly expected to become popular in the future.

The cost of the above-mentioned system is determined by the cost of the terminal system, and in order to reduce the terminal cost, it is not a good idea to use commercial power as the operating power source for each terminal. It is necessary to operate using the electric power that is generated. That is, it is important for the terminal system to turn on the power supply circuit only when it receives activation, and to turn off the power supply circuit when it is not needed. For this purpose, a network control device is installed between the subscriber telephone line and the terminal, which turns on the power only when activated by an activation signal of a specific polarity, and connects the terminal circuit to the subscriber telephone line using a specific AC signal. There is.

However, various signals necessary for a call connection are transmitted to the subscriber telephone line, and in particular, the polarity of the 16 Hz calling signal is alternately reversed, and the shelf width thereof is large. Therefore, 16Hz
The terminal system is activated by the signal and the power is turned on, but since no specific AC signal is input, no data is sent from the terminal system. However, when the power of the terminal system is turned on, , which affects the telephone system's 16Hz ringing signal. In order to prevent this, a 16 Hz detection circuit is conventionally provided, and the power is controlled to be turned off based on the 16 Hz detection output. However, in the conventional circuit described above, the 18Hz detection circuit is
The drawback is that it affects the waveform of the 16 Hz ringing signal for several cycles between detecting the z signal and turning off the power.

OBJECTS OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional drawbacks, and to provide a 18Hz countermeasure for a network control device, which distinguishes between an activation signal and a 16Hz calling signal, and prevents the power from being turned on depending on the 16Hz calling signal. The purpose is to provide circuits.

Composition of the Invention The 16Hz countermeasure circuit of the network control device of the present invention includes a timer circuit that is activated by an activation signal of a specific polarity and turns on a switch circuit described later after a certain delay time, and a activation signal of a specific polarity and the timer circuit. Equipped with a switch circuit that is turned on by delayed output and connects the subscriber telephone line and the power supply circuit described later, and a power supply circuit that supplies operational power to the data terminal circuit using power supplied from the subscriber telephone line. It is characterized by

Embodiments of the Invention Next, the present invention will be described in detail with reference to five drawings.

The figure is a block diagram showing one embodiment of the present invention. That is, the switch circuit 1 is connected to the subscriber telephone line 10 and turns on when a startup signal of a specific polarity is input, and the switch circuit 1 is connected to the subscriber telephone line 10 and turns on when a startup signal of a specific polarity is input, and the switch circuit 1 is connected to the subscriber telephone line 10 until a certain delay time elapses after the polarity of the subscriber telephone line 10 becomes the activated state. A timer circuit 2 is provided for controlling the switch circuit 1 to delay turning on, and when the switch circuit 1 is turned on, the subscriber telephone line 1O and the power supply circuit 3 are connected. The power supply circuit 3 is a circuit for supplying operating power to a circuit that determines activation based on a specific AC signal and a data terminal circuit including a modem and the like. The timer circuit 2 is composed of, for example, a resistor and a capacitor, and controls the switch circuit 1 to be in an on state using a timer output 20 when the charging voltage of the capacitor exceeds a certain value. That is, when an activation signal of a specific polarity is input from the subscriber telephone line 10, the timer circuit 2 outputs the timer output 20 after a certain delay time, and the switch circuit l
is turned on, the subscriber telephone line IO is connected to the power supply circuit 3, and the power supply circuit 3 supplies operating power to a data terminal circuit (not shown) using the power supplied from the subscriber telephone line 10. The data terminal circuit is brought into operation by the power supplied from the power supply circuit 3, and is activated when a specific AC signal is input from the subscriber telephone line 10 to send out data.

Join phone! ! When the polarity of 10 is reversed, the switch circuit 1 is turned off, and the power supply circuit 3 and the data terminal circuit are disconnected from the subscriber telephone line 10.

When an 18Hz signal is input from subscriber telephone line IO,
Since the time constant of the timer circuit 2 is sufficiently large compared to 16H2, the timer output 20 is not output from the timer circuit 2. Therefore, the switch circuit l is in the off state, and the subscriber telephone line 10 and the power supply circuit 3 are not connected. Therefore, this embodiment has the effect that it does not have any effect on the 16Hz signal waveform on the subscriber telephone line 10.This embodiment does not require a 16Hz detection circuit unlike the conventional one, and the timer circuit 2 is a resistor. Since it can be constructed using only capacitors, it is also effective in reducing the cost of the network control device.

Effects of the Invention As described above, in the present invention, the subscriber telephone line is activated by a starting signal of a specific polarity, and is turned on after a certain delay time to connect the subscriber telephone line to the power supply circuit. This has the effect of preventing the 16 Hz signal on the line from flowing into the power supply circuit 3 and being adversely affected. Furthermore, the configuration is simple and effective in reducing the cost of the network control device.

[Brief explanation of the drawing]

The figure is a block diagram showing one embodiment of the present invention. In the figure, l: switch circuit, 2: timer circuit, 3
: Power supply circuit, 10: Subscriber telephone line, 20: Timer output. Applicant: NEC Corporation Agent: Patent Attorney: Toshimune Sumita

Claims (1)

[Claims] a timer circuit that is started by a starting signal of a specific polarity and turns on the switch circuit described later after a certain delay time; and a timer circuit that is turned on by the starting signal of a specific polarity and the delayed output of the timer circuit to connect the subscriber telephone line and the power supply circuit described below. 16H of a network control device characterized by comprising a switch circuit for connection, and a power supply circuit that supplies operational power to a data terminal circuit using power supplied from a subscriber telephone line.
Z countermeasure circuit.