JPH0779411B2 - Facsimile machine transmission mode discrimination method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a transmission mode determination method of a facsimile apparatus that determines a transmission mode of a partner apparatus when receiving a call.

[Technical background of the invention]

Conventionally, a device having a G II mode and a G III mode is well known as a facsimile device, but in recent years, a device having a so-called mini-fax transmission mode (hereinafter referred to as MF mode) has been invented. .

When the other party is a G II mode facsimile apparatus, this type of apparatus has frequency components of 1850 Hz and 1650 Hz after the incoming call is detected, as shown in FIG. 1 (a).
The digital identification signal DIS of 0 bps is sent, and after a certain period of time, the group identification signal GI of 1850 Hz ± 6 Hz is 1.5 seconds ± 15%.
The digital identification signal DIS is transmitted again after the transmission. On the other hand, when a group command signal (sending min1.5 seconds max10 seconds at 2100Hz ± 10Hz) GC arrives from the partner device and a 2100Hz phase signal PS arrives, the self-synchronization is adjusted by this phase signal PS. , 1650Hz ± 6Hz reception ready confirmation signal CFR after the above phase signal PS is disconnected
After that, the operation shifts to the operation of receiving the image signal PC from the partner device.

On the other hand, when the partner device is a MF mode facsimile device, for example, as shown in FIG. 1 (b), the digital identification signal DIS is first sent after the incoming call is detected, and the phase signal sent from the partner device is sent. Performs self-synchronization by PS, and when this synchronization is completed, sends a reception preparation completion confirmation signal CFR of 1080Hz ± 4Hz and operates so as to shift to the reception operation of the image signal PC coming from the other device after that. To do.

By the way, in order to perform each of the above operations, it is necessary to determine whether the transmission mode of the partner device is the G II mode or the MF mode. Conventionally, this transmission mode is determined by the group command signal. This is done by detecting the arrival of GC.

[Problems of background technology]

However, some facsimile machines, for example, G III
As shown in FIG. 1 (c) immediately after the end of the transmission of the group identification signal GI, such as a device in the G II mode (former G II mode) before the standard of the mode was established or a device that cannot detect the digital identification signal. There is one that returns a group command signal GC as shown in (4). When such a device is the partner, the digital identification signal DIS transmitted by itself and the group command signal GC from the partner device exist in the same time zone.
In that case, since the facsimile device is generally configured not to perform the receiving operation during the transmitting operation, it cannot receive the group command signal GC, and as a result, the partner device is in the G II mode. Instead, it was misidentified as MF mode, and the operation reliability was extremely low.

Further, in order to prevent the above-mentioned misjudgment, the signal form is devised to shorten the preamble signal between the group identification signal GI and the digital identification signal DIS, and thereby the digital identification signal DIS and the group command signal GC are overlapped. A method of reducing reception and enabling reception of the group command signal GC has also been considered. However, such a method requires complicated signal processing circuits and processing operations for shortening the preamble signal, resulting in a complicated configuration and high price, and even if it satisfies the conditions in the standard. It was not desirable.

[Object of the Invention] The present invention makes it possible to accurately determine a transmission mode with a simple configuration even for a device that immediately returns a group command signal after transmitting a group identification signal. It is an object of the present invention to provide a method for determining the transmission mode of a facsimile machine, which can be improved.

[Outline of Invention]

In order to achieve the above object, the present invention focuses on the fact that the length of the phase signal is different between the G II mode and the unique transmission mode such as the MF mode which is the transmission mode for the mini-fax, The transmission mode of the partner device is provided by providing a clocking means for clocking for a predetermined period set in advance from the time when the phase signal is detected, and detecting whether or not the phase signal ends during the clocking period of this clocking means. Is determined.

Example of Invention

FIG. 2 is a circuit block diagram of a facsimile apparatus to which the transmission mode discrimination system according to the embodiment of the present invention is applied. This device has a microprocessor (CPU) 1 to which a read only memory (ROM) 2 and a random access memory (RA) are connected via a bus 4.
M) 3 is connected, and the transmitter 5, the receiver circuit 6, the control signal detector 7, and the event timer 8 are also connected. A line 9 is connected to a network control unit (NCU) (not shown). The transmitting unit 5 is the CPU 1
The control signal generation circuit 5a is composed of a programmable oscillator that generates a control signal of a predetermined frequency in accordance with the command of 1., and the transmission circuit 5b that sends the control signal generated from the circuit 5a to the line. On the other hand, the receiving circuit 6 is connected to the line 9
The phase signal PS and the image signal PC are demodulated and digitized among various signals that have come through the above. The control signal detection unit 7 also includes a binarization circuit 7a that binarizes various control signals (including phase signals) that arrive via the line 9, and a frequency that detects the frequency of the signal that arrives from the binarized output. It is composed of a detection circuit 7b. Event timer 8
According to an instruction from the CPU 1, the clock counts for a predetermined period set in advance and generates a clock signal of, for example, “H” level during this clocking operation period. ROM2 and RAM3
Are stored programs and control data indicating the control procedure of the CPU 1, respectively.

Next, the transmission mode discrimination method of the present embodiment will be described based on the above configuration. FIG. 3 is a flowchart showing the control procedure.

When an incoming call is generated, the CPU 1 first issues an instruction to the control signal generation circuit 5a to generate a digital identification signal DIS which is an initial identification signal, and transmits this digital identification signal DIS from the transmission circuit 5b to the line 9 in FIG. ), (B). When the transmission of this digital identification signal DIS is completed,
It is determined whether or not the phase signal PS (2100 Hz) is detected by the frequency detection circuit 7b. If the phase signal PS is not detected by this determination, the group identification signal GI and the digital identification signal DIS, which are the initial identification signals, can be read and generated from the transmission unit 5 after a certain period of time, and as shown in FIG. 1 (a). To send. Then, after the transmission of these signals is completed, the operation shifts to the detection operation of the group command signal GC and the phase signal PS from the partner device. On the other hand, if the phase signal PS is detected in the determination, the operation of detecting the phase signal PS is continued as it is. Here, the detection of the phase signal PS is performed as follows. That is, the phase signal PS is obtained by repeating a full carrier of 2100 Hz with a lost time (carrier interruption period) of about 4 to 6% inserted in the middle at a 1/6 second cycle as shown in FIG. Has become. Therefore, the position of the carrier break period that arrives every 1/6 seconds is detected, and when this break period is repeated three times in a 1/6 second cycle, this signal is recognized as the phase signal PS. .

Now, when the phase signal PS is detected in this way, the CPU 1 executes the third
As shown in the figure, first issue a drive instruction to the event timer 8,
As a result, the time counting operation of the event timer 8 is started.
Then, after driving the timer 8, the CPU 1 performs phase matching of its own device based on the phase signal data obtained by the receiving circuit 6. When this phase matching is completed, the CPU 1 first determines whether the phase signal PS has been detected, that is, whether the phase signal PS has still arrived. And the phase signal PS
If is detected, it is determined whether or not the event timer 8 has timed out, and the detection determination of the phase signal PS and the time-up determination are repeated while the time is not timed up.

By the way, the transmission period of the phase signal PS is set to 6 ± 0.5 seconds in the G II mode, and 30 to 40 seconds in the MF mode. Therefore, whether the partner device is in the G II mode or the MF mode can be determined by monitoring the transmission period of the phase signal PS. Therefore, in this embodiment, the time period of the event timer 8 is set to about 8 seconds to determine the length of the phase signal PS transmission period.

That is, in the repetition period of the detection determination and the time-up determination of the phase signal PS, if the phase signal PS cannot be continuously detected for 300 msec before the event timer 8 times out, it is determined that the phase signal PS is disconnected. , The transmission mode of the partner device at this time is recognized as G II mode. On the other hand, when the event timer 8 times out while the phase signal PS is still detected, the transmission mode of the partner device at this time is recognized as the MF mode.

Then, when the transmission mode of the partner device is determined, CPU1
After that, the control signal is transmitted and received in accordance with a preset control procedure for each mode, and the image signal is received.

In this way, according to the transmission mode determination method of the present embodiment, G
Since the II mode and the MF mode are discriminated not by the presence or absence of the group command signal GC but by the length of the transmission time of the phase signal PS, it is assumed that the partner device is an old G II mode device. As shown in Fig. 1 (c), the digital identification signal
Even if the group command signal GC arrives during the DIS transmission period, it can be discriminated as the G II mode without being discriminated as the MF mode. Further, in order to discriminate the present embodiment, it is only necessary to provide the event timer 8, and as a result, compared with the conventional system using a special signal processing circuit and a control circuit for operating the transmitting and receiving systems simultaneously. Thus, there is an advantage that the circuit configuration can be greatly simplified. Therefore, according to the present embodiment, it is possible to provide a facsimile apparatus having a simple structure and capable of performing accurate mode determination.

The present invention is not limited to the above embodiment.
For example, the time counting operation by the event timer may be performed by software by the CPU 1. By doing so, the event timer can be eliminated, and thus the circuit configuration can be further simplified. Further, the transmission mode determination method of the present invention and the conventional method of detecting the presence or absence of the group command signal GS may be used together. That is, when it is determined that the partner device is in the G II mode by the conventional method, this determination result is used as it is, while when it is determined that the partner device is in the MF mode, the determination result by the method of the present invention is used. It suffices to recognize the transmission mode of the side device. This makes it possible to accurately determine the transmission mode for the old G II mode device.
In the case of the G II mode device, high speed mode discrimination can be performed. In addition, the circuit configuration and the time measured by the time measuring means can be variously modified and implemented without departing from the scope of the present invention.

〔The invention's effect〕

As described in detail above, the present invention is provided with a clocking means for clocking a predetermined period from the time when the phase signal is detected,
The transmission mode is determined by detecting whether or not the phase signal ends during the time counting operation of the time measuring means.

Therefore, according to the present invention, even for a device that returns an immediate group command signal after transmitting a group identification signal,
It is possible to provide a transmission mode determination method for a facsimile apparatus that can accurately determine the transmission mode without complicating the circuit configuration and improve the operation reliability.

[Brief description of drawings]

1 (a) to 1 (c) are timing charts of signal transmission / reception for explaining a conventional transmission mode discrimination method, and FIGS. 2 to 4 explain a transmission mode discrimination method in an embodiment of the present invention. 2 is a circuit configuration diagram of a facsimile apparatus to which the present system is applied, FIG. 3 is a flowchart showing a control procedure of the present system, and FIG. 4 is a diagram showing a signal form of a phase signal. 1 ... CPU, 2 ... ROM, 3 ... RAM, 4 ... Bus, 5 ...
… Transmitting unit, 5a …… Control signal generating circuit, 5b …… Transmitting circuit,
6 ... Receiving circuit, 7 ... Control signal detecting section, 7a ... Binarizing circuit, 7b ... Frequency detecting circuit, 8 ... Event timer,
9 ... Line, DIS ... Digital identification signal, GI ... Group identification signal, GC ... Group command signal, PS ... Phase signal, CFR ... Reception ready confirmation signal, PC ... Image signal.

Claims (1)

[Claims] 1. After the call is made, an initial identification signal returned from the device on the other side is detected, and after this detection, a group command signal and a phase signal formed by repeating intermittently a predetermined pattern are transmitted for a first predetermined period. The CCITT standard G II mode is used for transmission, and the transmission is performed according to a unique transmission mode for transmitting a phase signal, which is formed by repeating intermittent patterns of a predetermined pattern, for a second predetermined period that is longer than the transmission period of the phase signal in the above device. In a facsimile device that can be connected to each of the devices, a detecting unit that detects the phase signal, and a second predetermined period longer than the first predetermined period from the time when the phase signal is detected by the detecting unit. A time measuring means for measuring time of a predetermined time set within a range shorter than the time is provided, and the phase signal ends during the time measuring period of this time measuring means. By whether transmission mode determination method of a facsimile apparatus is characterized in that so as to determine the transmission mode of the partner apparatus at that time.