JPH01128661A - Network control circuit - Google Patents

Abstract

PURPOSE:To prevent a pseudo-incoming from a telephone set by switching control to a telephone set side after a constant time passes when a line is released. CONSTITUTION:When the necessity of automatic announcement is generated, a relay activating circuit 13 is operated by a signal from a main control part 9 and a relay contact 10 is switched to a communication control part side. Simultaneously, a transistor 12 is turned on and a direct current loop is formed in a route that a telephone line connecting terminal L1 the contact of a divider 3 the relay contact 10 a diode bridge 11 the transistor 12 a communication control part 5 the diode bridge 11 the contact of the divider 3 a telephone line connecting terminal L2. After the constant time passes, the transistor 12 repeats turning on and off by a signal from the main control part 9 and a dial signal is sent. Thus, since the control is switched to the telephone set side after the constant time passes when communication is finished, the switching can be executeed after a ringing is erased when the line is released and a phenomenon that the telephone set judges the ringing as a calling signal is erased. Then, the pseudo-incoming can be prevented.

Description

[Detailed Description of the Invention] (Industrial Application Field) The purpose of the present invention is to send home security information and other information to a remote center by automatic dialing using a telephone line. This paper relates to the network control circuit for automatic reporting equipment.

(Prior Art) FIG. 3 is a block diagram of the periphery of a network control circuit of a conventional automatic reporting device. In the figure, 1 is a telephone line input terminal, 2 is a telephone connection terminal, 3 is a disconnector provided to switch and connect the telephone, and 4 is a relay contact that serves both to capture the line and send out a dial signal. , 5 is a communication control unit that executes and controls the information reporting 2 communication, 6 is an incoming call detection circuit that detects an incoming call from the outside, and 7 is a main phone detection circuit that detects the usage status of the connected phone. , 8 is a relay starting circuit for controlling the relay contact 4, and 9 is a main control section of the automatic notification device.

Next, the operation will be explained. First, in order to perform automatic notification, the separator 3 is switched as shown in FIG. Relay contact 4 is also normally in the position shown in FIG. This is a standby state, indicating that control is on the phone side. Here, when it becomes necessary to perform automatic reporting, the relay activation circuit 8 is activated by a control signal from the main circuit, and the relay contact 4 is moved to the communication control unit side, and automatic dialing is performed to execute one communication. When the communication is completed, the relay contact 4 returns to the position shown in FIG. 3 and enters a standby state.

(Problems to be Solved by the Invention) In the conventional network control circuit described above, after the end of the communication, the line is opened and the control is switched to the main telephone side using the relay contact 4, so the telephone may receive a false call. There are cases where the ringer is turned off.

The reason for this is that when the telephone captures the line, the polarity of the line is reversed, so when the communication ends and the reversed state returns to the original state, that is, when the line is released, the direct current causes ringing, which the telephone This is because the operator mistakenly thought that a 167 call signal had come and set off the ringer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a network control circuit that eliminates the drawbacks of the prior art and switches control to the telephone side after a certain period of time has elapsed after opening the line after communication ends, thereby preventing pseudo-incoming calls.

(Means for Solving the Problems) The network control circuit of the present invention has a function of capturing a telephone line, a function of creating a dialing signal, a function of detecting a calling signal from the line, and a function of detecting a connected telephone. In a network control circuit that has a function of detecting usage status, when the line is released after one communication and switched to the telephone side, the transistors of the line capture relay and the dial signal sending transistor are controlled by the main control unit. After the line is turned off and the line is released, the relay is switched after a certain period of time to prevent false calls from being received by the connected telephone.

(Function) According to the present invention, after a certain period of time has passed after the end of one communication,
Since the control is switched to the telephone side, the switching can be performed after the ringing when one line is opened disappears, and the phenomenon in which the telephone determines ringing as a calling signal is eliminated, and pseudo-incoming calls can be prevented.

(Example) An embodiment of the present invention will be described based on FIG.

FIG. 1 is a block diagram showing the configuration of the network control circuit of the present invention;
FIG. 2 is a timing chart of the operation of the line capture relay contact and the dial signal sending transistor of the circuit of FIG. In this figure, the same parts as those in the conventional example shown in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted. 1
0 is a relay contact for capturing the line, 11 is a diode bridge to keep the direction of current flowing even if the polarity of the line is reversed, 12 is a transistor for creating a dial signal, and 13 is a relay This is a starting circuit for contact 10.

Next, the operation will be explained. In FIG. 1, the separator 3. The position of relay contact 10 indicates a standby state. Further, at this time, the transistor 12 is off. When the need for automatic notification arises from this state, the relay starting circuit 13 is activated by a signal from the main control section 9, and at the same time the relay contact 10 is switched to the communication control section side, the transistor 12 is turned on.
Telephone line connection terminal Li → Disconnector 3 contact → Relay contact L
O→Diode bridge 11→Transistor 12→Communication control section 5→Diode bridge ■1→Contact of disconnector 3→
A DC loop is formed along the path of the telephone line connection terminal L2.

Thereafter, after a certain period of time has elapsed, the transistor 12 is repeatedly turned on and off by a signal from the main control section 9, and a dial signal is sent out. The transistor 12 remains on after sending the dial signal, and the communication control unit performs communication. When the communication is finished, a signal from the main control section first turns transistor 1 on.
2 turns off and cuts the loop. At that time, the ringing described above occurs when the polarity is restored, but the ringing does not reach the connected telephone because the relay contact 10 is still on the communication control unit side. Then, after a certain period of time has passed and the ringing has disappeared, the relay contact 10 is returned to the telephone side.

(Effects of the Invention) According to the present invention, since the control is switched to the telephone after a certain period of time has passed after the line is opened, it is possible to prevent false incoming calls from the telephone.

Considering the current situation where automatic reporting of certain information is often carried out late at night, this control has an extremely large practical effect as a function of an automatic reporting device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a network control circuit according to an embodiment of the present invention, Fig. 2 is a timing chart of the same line capture relay contact and dial signal sending transistor, and Fig. 3 is a block diagram of a conventional network control circuit. be. 1... Subscriber telephone line input terminal, 2... Telephone connection terminal, 3... Disconnector, 5... Communication control unit,
6...Call signal detection circuit, 7...Telephone in use detection circuit, 9...Automatic notification device main control unit, 10.
...Line capture relay contact, 11...Diode bridge, 12...Dial signal sending transistor, 1
3...Line capture relay activation circuit. Patent applicant Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] In a network control circuit that has a function of capturing a telephone line, a function of creating a dialing signal, a function of detecting a calling signal from the telephone line, and a function of detecting the usage status of the connected telephone, after the end of communication, , when the telephone line is opened and switched to the telephone side, the transistors of the relay for capturing the telephone line and the transistor for transmitting the dial signal are turned off under control from the main control unit, and the telephone line is opened; , A network control circuit characterized in that it prevents false incoming calls from a connected telephone by switching a relay after a certain period of time delay.