JPH04423B2 - - Google Patents

Description

[Detailed Description of the Invention] <Field of the Invention> The present invention relates to a terminal device on the side of a central device in roadside communication that communicates traffic information, etc. between a terminal device connected to the central device via a communication line and a vehicle. transmitter power supply
Concerning a central control system for ON/OFF control.

<Prior art and its problems> Conventionally, in roadside communication, in which traffic information such as traffic congestion caused by an accident is communicated between a terminal device connected to a central device via a communication line and a vehicle, the communication line Or, if a problem occurs with the terminal, go to the location where the terminal is installed and turn off the power to the terminal's transmitter.
This requires a lot of labor and time, and furthermore, in the event of an abnormality, the transmitter may emit unpleasant sounds and cause traffic disturbances until the transmitter power is turned off. There are drawbacks such as the possibility that drivers listening to the information may feel uncomfortable.

<Object of the Invention> The present invention has been made in view of the above-mentioned points, and the present invention has been made in view of the above-mentioned points.
The purpose is to eliminate the above-mentioned disadvantages by enabling OFF control and, in the event of an abnormality in the communication line or terminal, the transmitter power of the terminal is promptly turned off at the central unit.

<Structure and Effects of the Invention> In order to achieve the above-mentioned object, the present invention provides a terminal with a combination of signals from the central device that corresponds to ON/OFF control of the transmitter power supply. The first and second filters respectively filter and output control signals of two different frequencies to be transmitted.
the filter circuit, and the combination of the output signals from the first and second filter circuits.
A switching means is provided for determining ON/OFF and switching the transmitter power supply ON/OFF.

Therefore, according to the present invention, the transmitter power of the terminal device can be turned on by transmitting control signals of two different frequencies in a specific combination from the central device in response to the desired ON/OFF operation. /OFF control, which eliminates the need to go to the location where the terminal is installed and turn the transmitter power ON/OFF, which is required in the past, and can significantly reduce labor costs and time loss. Become. Furthermore, in the event of an abnormality in the communication line or terminal, the central unit can immediately turn off the power to the transmitter, which eliminates the possibility of transmitting unpleasant sounds that cause discomfort to the driver.

<Description of Examples> Examples of the present invention will be described in detail below with reference to the drawings. The drawing is a simplified configuration diagram of an embodiment of the present invention. The central device 1 is connected to the terminal devices 2 through a communication line 3. Central machine 1 is terminal machine 2
2 for audio signals such as traffic information to be transmitted to the terminal 2 or for controlling the power ON/OFF of the transmitter 4 of the terminal 2.
An amplifier 5 for amplifying control signals of two different frequencies f1 and f2, an amplifier 11 for amplifying the audio signal transmitted from the terminal 2, and a part of the audio signal given via the line 6 as described later. transmission abnormality detection means 8 for detecting transmission abnormality based on the signal branched from the terminal 2 and the audio signal given via the line 7 which is transmitted to the terminal 2 and then transmitted again from the terminal 2; A warning buzzer 9 and a warning lamp 10 are provided as warning means for warning of transmission abnormality based on the output from the abnormality detection means 8.

This transmission abnormality detection means 8 detects a signal obtained by branching a part of the audio signal given via the line 6,
After being transmitted to the terminal device 2, the audio signal transmitted from the terminal device 2 again through the line 7 is converted into a digital signal, the levels of both digital signals are compared, and both digital signals are converted within a predetermined time. When the number of times the signal levels match is equal to or greater than a predetermined number, it is determined that the transmission is normal; otherwise, it is determined that the transmission is abnormal and the warning buzzer 9 and warning lamp 10 are driven. This predetermined number of times is selected to be a sufficient number of times to prevent malfunctions due to various noises other than voice signals and delays in voice signals caused by the communication line 3.

In the central device 1, when there is no abnormality in the communication line 3 and the terminal device 2, audio signals such as traffic information are transmitted to the terminal device 2, and from the terminal device 2 to a vehicle (not shown). When the transmission abnormality detection means 8 detects an abnormality in the communication line 3 or the terminal device 2 as described above, the transmitter 4 power supply of the terminal device 2 is turned off.
To turn off the terminal 2, send control signals of two different frequencies, f1 and f2, in a combination that corresponds to turning off.
Transmit it to the transmitter 4 power supply as described below.
Turn it off. In this way, two different frequencies f1 and f2
The reason why these two signals are used as control signals is to prevent malfunctions in turning ON/OFF the power source of the transmitter 4 based on the audio signals, since the audio signals also have frequency components. When the abnormality in the communication line 3 and the terminal device 2 is resolved, the transmitter 4 of the terminal device 2 is transmitted from the central device 1.
In order to turn on the power, both control signals are transmitted to the terminal 2 in a combination corresponding to ON, the transmitter 4 is turned on, and then the original audio signals such as traffic information are transmitted again.

The terminal device 2 includes an amplifier 12 that amplifies the audio signal or control signal from the central device 1, a transmitter 4,
The present invention further includes a transmitting antenna 13, a receiver 14, and a receiving antenna 15.
For power ON/OFF control, first and second filters filter and output control signals of two different frequencies f1 and f2 transmitted from the central unit 1 in combinations corresponding to ON/OFF, respectively. Filter circuits 16a, 16b and first and second filter circuits 16
Based on the combination of output signals from a and 16b, the ON/OFF state is determined and the transmitter 4 power supply is switched on.
Switching means 17 for switching ON/OFF
Be prepared.

The first filter circuit 16a includes a first band filter 22a that passes only the control signal of frequency f1;
A digital converter 23a for converting the signal from the first band filter 22a into a digital signal, and the second filter circuit 16b has a frequency f2
a second band filter 2 that passes only the control signal of
2b, and a digital converter 23b that converts the signal from the second band filter 22b into a digital signal.
It consists of

The switching means 17 takes the AND of both signals from the first and second filter circuits 16a and 16b.
an AND circuit 24; a code converter 25 that determines ON/OFF based on the output from the AND circuit 24 and outputs a set/reset signal; It consists of a switching circuit 28 that switches ON/OFF of the transmitter 4 power supply, and this switching circuit 28 has a relay contact 26 and a relay drive circuit 27.
It consists of

This terminal device 2 transmits audio signals from the central device 1 from a transmitting antenna 13 to communicate traffic information and the like with vehicles (not shown). The transmitted audio signal is received by the receiving antenna 15 and transmitted to the central device 1 again. In addition, 18, 19, 20, 21
is a line transformer.

In the central control system for roadside communication of the present invention, when the transmitter 4 power is to be turned on or
If you want to turn it off, use two different frequencies f1,
The f2 control signal is transmitted to the terminal 2 in a specific combination corresponding to ON/OFF. In the terminal device 2, the control signal of frequency f1 passes through the first filter circuit 16a and is applied to the AND circuit 24, and the control signal of frequency f2 passes through the second filter circuit 16b and is applied to the AND circuit 24.
The AND circuit 24 performs the logical product of both signals and provides the result to the code converter 25. Code converter 25
Now, based on the output from the AND circuit 24, it is determined whether the transmitter 4 power source should be turned on or off, and a set/reset signal is sent to the relay drive circuit 27.
Output to. Relay drive circuit 27 turns relay contact 26 ON when a set signal is applied, and turns OFF relay contact 26 when a reset signal is applied.

In this way, in the present invention, it is possible to control ON/OFF of the power source of the transmitter 4 of the terminal device 2 on the central device 1 side.

[Brief explanation of drawings]

The drawing is a simplified configuration diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Central machine, 2...Terminal machine, 3...Communication line, 16a, 16b...First and second filter circuits, 17...Switching means, 24...AND circuit,
25...Code converter, 28...Switching circuit.

Claims (1)

[Claims] 1. Turning on/off the transmitter power of the terminal on the central machine side in roadside communication that communicates traffic information, etc. between the terminal connected to the central machine via a communication line and the vehicle.
It is a central control system for OFF control, and the terminal is equipped with two different frequencies transmitted from the central device in combinations corresponding to ON/OFF, respectively, for ON/OFF control of the transmitter power supply. a first filter that filters and outputs the control signals of
A second filter circuit and a switching means for determining the ON/OFF state based on the combination of output signals from the first and second filter circuits and switching the transmitter power supply ON/OFF. A central control system for roadside communications featuring: 2. The switching means includes an AND circuit that performs a logical product of both signals from the first and second filter circuits;
A code converter that determines ON/OFF based on the output from the AND circuit and outputs a set/reset signal; and a code converter that turns the transmitter power ON/OFF in response to the set/reset signal from the code converter. and a switching circuit that performs switching, and when a set signal is output from the AND circuit, the transmitter power is turned on, and when a reset signal is output, the transmitter power is turned off. A central control system for roadside communications as described in Scope 1.