JPH0337783B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] In a function that prevents incoming call collisions on a facsimile device based on the power polarity of the telephone line, even if the power polarity of the telephone line is reversed for some reason, the facsimile device can be operated without any problem. Made it possible to perform outgoing calls.

[Industrial application field]

The present invention relates to a facsimile device having an automatic dialing function, and in particular, to enable the facsimile device to operate without problems even if the polarity of the power supply of the telephone line is reversed to that when the facsimile device is installed, when the facsimile device creates a DC loop for making a call. Concerning a telephone line polarity monitoring method.

With the development of the information society, many facsimile devices have been installed and are being used frequently. This facsimile device is generally connected to a telephone line, has an automatic dialing function, and allows the user to select a desired party and transmit documents, drawings, etc.

When a facsimile machine makes a call using the automatic dialing function, before creating a DC loop for making a call, check the power polarity of the telephone line to prevent collision with an incoming call and check if the polarity is reversed from the normal polarity. , it is configured to determine that a call has arrived and stop the DC loop creation operation.

In other words, the exchange that makes up the public line reverses the polarity of the battery before sending a 16Hz signal for calling to the telephone, so the facsimile machine must detect this polarity reversal before making a call. is being determined.

Therefore, when installing a facsimile device, it is necessary to check the power polarity of the telephone line and connect it according to the normal power polarity, but there is no problem even if the power polarity of the telephone line changes after the facsimile device is installed. is necessary.

[Conventional technology]

FIG. 3 is a circuit block diagram showing an example of a conventional facsimile device.

The processor 1 operates by reading the program stored in the ROM 2, and when receiving an instruction to make a call, it checks the power polarity of the telephone line, so the line control circuit 5
control to close contact 7.

Therefore, depending on the power supply polarity of the telephone line, diode D
It is determined whether the current flows through the photocoupler 6 or is blocked and does not flow.

Here, for example, when no current flows through the photocoupler 6, assuming that the power polarity of the telephone line is in the normal state, the processor 1 checks whether there is a current value in the photocoupler 6 via the line control circuit 5, and determines whether the current is flowing. If it is, it is determined that the call has arrived by comparing it with the data stored in the memory 3, and if it is not flowing, it is determined that the call is normal, and the line control circuit 5 is controlled to close the contact 8.
Create a DC loop.

Therefore, conventional facsimile devices measure the normal power polarity of the telephone line when installed, connect based on the polarity of the data in the memory 3 determined by the facsimile device, and use that polarity as a reference to reverse the power polarity when a call arrives. was detecting whether or not.

[Problem that the invention seeks to solve]

As mentioned above, conventionally, when installing a facsimile device, the power polarity of the telephone line is measured and the telephone line is connected according to the polarity, so the connection of the telephone line from the exchange to the facsimile device may be reversed due to construction etc. In this case, when the power polarity of the telephone line is detected just before automatic dialing, even though there are no incoming calls during normal times, it is mistakenly determined to be an incoming call due to polarity reversal, and the process to create a DC loop is interrupted. .

Moreover, when an incoming call is received, it is erroneously determined to be normal, creating a DC loop and colliding with the incoming call.

Therefore, there is a problem in that normal operation cannot be performed thereafter.

[Means for solving problems]

FIG. 1 is a block diagram of a circuit showing one embodiment of the present invention.

Processor 1 closes contact 7, connects diode D and photocoupler 6 to the telephone line, and detects the power polarity of the telephone line determined by diode D.
It then compares it with the polarity data stored in the memory 3, and if it is reversed, it is determined that there is an incoming call and a timer 4 is set.

At the same time, the processor 1 closes the contact 9 and monitors the arrival of the 16 Hz calling signal, and when the timer 4 times out, it starts checking the power polarity of the telephone line again.

After repeating this a predetermined number of times, the memory 3
The configuration is such that the polarity data of is corrected.

[Effect]

In other words, as a result of checking the power polarity of the telephone line multiple times,
Even though the polarity is reversed, the subsequent 16Hz ringing signal cannot be detected within the time set by timer 4, which means that for some reason the telephone line is operating normally. It is determined that the power supply polarity is different from that when the facsimile device was installed, and the contents of the memory 3 that stores the power supply polarity during normal operation are changed.

〔Example〕

In FIG. 1, explanation will be made using FIG. 2 which shows a flowchart for explaining the operation of FIG. 1.

Processor 1 reads a program stored in ROM 2 and operates. When processor 1 receives an instruction to transmit a document, it closes contact 7 via line control circuit 5, and starts checking the power polarity of the telephone line as shown in FIG.

When contact 7 closes, current will either flow through diode D or be blocked depending on the power polarity of the telephone line. This state is detected by the photocoupler 6,
It is sent to the line control circuit 5. For example, if data is stored in the memory 3 that determines that the power supply polarity is reversed when current flows through the diode D,
When the processor 1 detects that current has flowed into the photocoupler 6 via the line control circuit 5, it transfers the current to the memory 3.
It is determined that the power supply polarity has been reversed.

When processor 1 determines that the power supply polarity has been reversed, it opens contact 7, sets timer 4, and closes contact 9.
It has a 16Hz ringing signal coming in via capacitor C.
If a 16Hz calling signal is received, photocouplers 10 and 1
1 and enters the line control circuit 5.

When the current flows through the photocouplers 10 and 11, the processor 1 determines that there is an incoming call, closes the contact 8 to create a DC loop, and shifts to processing for receiving data transmitted from the other party's facsimile device.

The processor 1 continues to detect the current flowing through the photocouplers 10 and 11, and when it receives a time-over interrupt signal from the timer 4, it checks whether this interrupt signal has been received a predetermined number of times, that is, the nth time.
If it is less than n times, contact 7 is closed and the same process as described above is performed to detect the power polarity of the telephone line.

If it is the nth time, the processor 1 changes the data for polarity verification in the memory 3, closes the contact 7, and shifts to the power supply polarity detection operation.

〔Effect of the invention〕

As explained above, the present invention not only allows the facsimile device to operate without any trouble even if the power polarity of the telephone line is reversed due to construction etc. after the facsimile device is installed, but also enables There is no need to check the power polarity of the telephone line before connecting, making installation work easier.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit showing an embodiment of the present invention, FIG. 2 is a flowchart explaining the operation of FIG. 1, and FIG. 3 is a block diagram of a circuit showing an example of a conventional facsimile device. . In the figure, 1 is the processor, 2 is the ROM, and 3 is the processor.
is a memory, 4 is a timer, 5 is a line set circuit,
6, 10, and 11 are photocouplers, and 7, 8, and 9 are contacts.

Claims (1)

[Scope of Claims] 1. A facsimile device having a function of detecting the power polarity of the telephone line, comparing it with the data in the memory 3, and stopping the creation of a DC loop when it is determined that there is an incoming call to prevent incoming calls from colliding, A timer 4 is provided which sends out a signal when a predetermined period of time has elapsed, and when it is determined that there is an incoming call based on the polarity of the power source, the timer 4 is set and then the incoming call signal is detected;
If the calling signal is not detected within a predetermined time based on the signal of the timer 4, the data in the memory 3 for determining the incoming call is changed after repeating the power polarity detection, timer setting, and ringing signal detection operations a predetermined number of times. A telephone line polarity monitoring method characterized by: