JPH0927894A - Facsimile signal transmission system - Google Patents

Abstract

(57) Abstract: To provide a facsimile signal transmission method capable of shortening the transmission time of a facsimile control signal and surely realizing facsimile transmission even if the number of links increases. In the facsimile signal transmission system, a link directly connected to a facsimile terminal F is provided with an initial signal discrimination function unit 2 and a processed signal transmission function unit 3. Starting of the facsimile control signal processing function unit 1 is controlled based on the signal that arrives first in the initial signal determination function unit 2, and transmission of the processed signal from the processed signal transmission function unit 3 is controlled. When the signal that first reaches the initial signal discrimination function unit 2 is a facsimile control signal, the facsimile control signal processing function unit 1 performs processing for guaranteeing the standard protocol. When the first signal reaching the initial signal discrimination function unit 2 is the processed signal, the facsimile control signal is not processed to guarantee the standard protocol. A flag signal sequence, a bit sequence, or a tone signal sequence can be used for the processed signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile signal transmission system. In particular, the present invention relates to a facsimile signal transmission method in which a digital transmission device for demodulating and transmitting a G3 facsimile signal is connected over a plurality of links via a repeater exchange to construct a network.

[0002]

2. Description of the Related Art FIG. 4 is a schematic configuration diagram of a facsimile signal transmission system according to the prior art. In the facsimile signal transmission system, the G3 facsimile signal output from the facsimile terminal F1 is transmitted to the relay exchange through the subscriber line exchange and the digital transmission device. The digital transmission device is, for example, a digital time division multiplexer (T
DM devices) T1 and T2 are used. TDM device T1,
Each of T2 is connected by a digital line SD such as a high speed digital leased line. Here, the TDM devices T1 and T
The connection between each of the two is defined as link 1.

On the other hand, the repeater exchange enables connection of a plurality of links, and a facsimile signal transmission system network is constructed. For example, when the relay exchange is connected to the facsimile terminal F2, the TDM devices T3 and T4 and the subscriber line exchange are interposed between the relay exchange and the facsimile terminal F2. The connection between each of the TDM devices T3, T4 is defined as link 2.

FIG. 5 is a diagram showing a signal state when a network is constructed. As shown in FIG. 5, the facsimile signal is transmitted as a modulated signal between the facsimile terminal F1 and the TDM device T1, and the facsimile signal is transmitted as a demodulated signal between the TDM devices T1 and T2. T
When the demodulated signal is transmitted between the DM devices T1 and T2, the efficiency of the line band can be improved. The facsimile signal is transmitted as a modulated signal between the TDM device T2 and the TDM device T3 via the repeater exchange. Similarly, the TDM devices T3, T
The facsimile signal is transmitted as a demodulated signal during the period 4 and the facsimile signal is transmitted as a modulated signal between the TDM device T4 and the facsimile terminal F2.

FIG. 6 is a block diagram of the above-mentioned facsimile signal transmission system. Reference numeral 1 is a facsimile control signal processing function unit. Facsimile control signal processing function unit 1
, The first facsimile control signal output from the facsimile terminal F1 is processed, and the processed first facsimile control signal is output to the repeater exchange. The first facsimile control signal processed by the repeater exchange is input to the facsimile control signal processing function unit 1, and the processed first facsimile control signal is further processed and output to the facsimile terminal F2. The facsimile control signal processing function unit 1 is installed independently in each of the links 1 and 2.

FIG. 7 is a diagram showing a sequence of facsimile control signals in the facsimile signal transmission system shown in FIG. FIG. 7 shows the relationship between each of the first facsimile control signal 4 and the processed first facsimile control signal 5 transmitted from the facsimile terminal F1 to the facsimile terminal F2 and the processing time in the middle.

Next, the system operation of the above-mentioned facsimile signal transmission system will be described.

In a network constructed by TDM devices that demodulate and transmit G3 facsimile signals,
The facsimile signal is demodulated at the entrance of the link and modulated at the exit of the link for transparent, real-time transmission. However, in the digital transmission device represented by the TDM device, only the standard protocol of G3 facsimile (ITU-TS standard T.30) is generally supported, and it is usually impossible to support various unique modes. is there. Therefore, even if it is called transparent transmission, some processing is performed on the facsimile control signal (for example, processing for deleting the NSF signal).
Is required, and an operation is required to prevent entering the original mode (each company's mode). Such an operation is performed in the facsimile control signal processing function unit 1 shown in FIG.

As shown in FIG. 7, in the facsimile control signal processing function unit 1 of each of the links 1 and 2, the operation (processing) for not entering the unique mode is the initial identification signal (NSF signal, CSI signal) of the facsimile signal. , DIS signal)
Done for Facsimile control signal processing function unit 1
In this case, since the processing is performed independently and sequentially, the facsimile control signal of the initial identification signal which is the first facsimile control signal 4 in the link 1 is transmitted from the facsimile terminal F1 to the facsimile terminal F2. The processing time is added to the transmission time. Further, the processing time of the facsimile control signal processing function unit 1 in the link 2 is added to the first facsimile control signal 5 processed by the facsimile control signal processing function unit 1 in the link 1. The first facsimile control signal 4
, The NSF signal is included, and in the first processed facsimile control signal 5, the NSF signal is deleted.

[0010]

In the above-mentioned facsimile signal transmission system according to the prior art, the following points are not taken into consideration. That is, in the facsimile signal transmission method, the process for operating the standard protocol without the G3 facsimile signal entering the unique mode (the process for the first facsimile control signal) is performed independently for each link, so the process for each link is performed. The time is added to increase the transmission time of the facsimile control signal. Particularly, when the number of links increases, the processing time corresponding to the number of links is added, and the transfer time of the facsimile control signal becomes longer than the permissible range, so that there are cases where facsimile transmission cannot be realized.

The present invention has been made to solve the above problems. Therefore, it is an object of the present invention to provide a facsimile signal transmission system which can shorten the transmission time of a facsimile control signal and can reliably realize facsimile transmission even if the number of links increases.

[0012]

In order to solve the above-mentioned problems, the invention according to claim 1 is to connect a digital transmission device for demodulating and transmitting a facsimile signal to a plurality of links via a repeater exchange. In the facsimile signal transmission method in which the network is constructed, the facsimile control signal processing function unit for performing processing for guaranteeing the standard protocol operation for the facsimile control signal, and the facsimile control signal are processed by the facsimile control signal processing function unit. The processed signal indicating that the processed signal is a processed signal sending function unit that can be sent prior to sending the processed facsimile control signal, and whether the first signal to arrive is the facsimile control signal or the processed signal. When it is determined that the fax control signal processing function unit is activated, Sends the processed signal from the processed signal transmission function unit performs the processing to re control signal,
An initial signal determination function unit that does not activate the facsimile control signal processing function unit and does not process the facsimile control signal when it is determined that the signal is a processed signal.

According to the first aspect of the invention, the link directly connected to the facsimile terminal is provided with the initial signal discrimination function section and the processed signal transmission function section. Activation of the facsimile control signal processing function unit is controlled based on the signal that arrives first in the initial signal determination function unit, and control of the transmission of the processed signal from the processed signal transmission function unit is performed. If the first signal reaching the initial signal discrimination function unit on the link on the transmission side is the first facsimile control signal, the facsimile control signal processing function unit performs processing to guarantee the standard protocol and then the processed first facsimile control signal. Is generated. Based on the processed signal sent on the sending link,
In the link on the receiving side, the signal that reaches the initial signal discrimination function unit first becomes the processed signal, so the processed first facsimile control signal is transmitted to the facsimile terminal without being processed to guarantee the standard protocol. It Therefore, the processing for guaranteeing the standard protocol is not performed in the link on the receiving side, so that the transmission time of the facsimile control signal can be shortened.

According to a second aspect of the present invention, in the facsimile signal transmission system according to the first aspect, the processed signal transmitting function section transmits any one of a flag signal string, a bit string and a tone signal as a processed signal. It is characterized by being able to do it.

In the invention of claim 2, any one of a flag signal string, a bit string and a tone signal can be used as the processed signal.

According to a third aspect of the present invention, in the facsimile signal transmission system according to the first or second aspect, the processed signal which is connected to the initial signal discrimination function unit and is recognized and the processed signal are recognized. It is characterized by comprising a detection-processed signal length setting unit capable of setting a signal length to be recognized.

According to the third aspect of the invention, since the detection-processed signal length setting unit is added, it is possible to flexibly deal with network construction.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The constitution of the present invention will be described below together with the embodiments of the present invention.

First Embodiment of the Invention FIG. 1 is a block diagram showing a schematic configuration of a facsimile signal transmission system according to a first embodiment of the present invention. In FIG. 1, the facsimile signal transmission system is
That is, a facsimile control signal processing function unit 1 and an initial signal discrimination function unit 2 are added to a TDM device as a digital transmission device.
And a processed signal sending function unit 3.

The facsimile control signal processing function unit 1 of the facsimile signal transmission system processes the facsimile control signal (initial identification signal) for guaranteeing the standard protocol operation of the G3 facsimile, as described above.

The initial signal discriminating function unit 2 discriminates whether the signal that arrives first is a facsimile control signal or a processed signal indicating that the processing for guaranteeing the standard protocol operation has already been performed. In the embodiment of the present invention, a flag signal string of a specific length is used for the processed signal. When the initial signal determination function unit 2 determines that the first signal to arrive is the facsimile control signal, the facsimile control signal processing function unit 1 is activated, and the facsimile control signal is subjected to processing for guaranteeing the standard protocol operation. On the other hand, when the initial signal determination function unit 2 determines that the first signal to arrive is the processed signal, the facsimile control signal processing function unit 1 is not activated, and the process for guaranteeing the standard protocol operation for the facsimile control signal is not performed. Not applied.

The processed signal sending function unit 3 is activated when the first signal received by the initial signal discrimination function unit 2 is a facsimile control signal, and is processed by the facsimile control signal processing function unit 1 for the first facsimile control. A processed signal (a flag signal string of a specific length) is transmitted prior to the signal transmission. The processed signal is sent from the link that received the first facsimile control signal (eg, link 1) to the link directly connected to this link (eg, link 2).

FIG. 2 is a diagram showing a sequence of a facsimile control signal in the facsimile signal transmission system shown in FIG. As shown in FIG. 2, the first facsimile control signal 4 is transmitted from the facsimile terminal F1 directly connected to the link 1. In the link 1, the first facsimile control signal 4 is processed in the facsimile control signal processing function unit 1 to guarantee the standard protocol operation,
This processed first facsimile control signal 5 is transmitted. Prior to the sending of the first processed facsimile control signal 5, the processed signal sending function unit 3 sends a processed signal (a flag signal string of a specific length). In the link 2, the processed signal first arrives at the initial signal discrimination function unit 2 and the activation of the facsimile control signal processing function unit 1 is stopped in the initial signal discrimination function unit 2. Therefore, the facsimile terminal directly connected to the link 2 The first processed facsimile control signal 5 reaches the machine F2 as it is. That is, the facsimile terminal F2 directly connected to the link 2 from the link 1
The first facsimile control signal 5 processed in the areas up to is transmitted transparently.

Next, the system operation of the above-mentioned facsimile signal transmission system will be described.

First, the first facsimile control signal 4 is transmitted to the link 1 from the facsimile terminal F1 directly connected to the link 1. In the link 1, the initial signal discrimination function unit 2 discriminates whether the first signal to arrive is the first facsimile control signal 4 or the processed signal. This judgment is autonomously made on the link 1. If it is determined that the facsimile control signal 4 is the first facsimile control signal 4, the facsimile control signal processing function unit 1 is activated, the processing for guaranteeing the standard protocol operation is performed on the first facsimile control signal 4, and the processed first facsimile control is performed. Signal 5 is generated. The initial signal discrimination function unit 2 that has made the above discrimination activates the processed signal transmission function unit 3 together with the activation of the facsimile control signal processing function unit 1. When the processed signal sending function unit 3 is activated, the processed signal is sent to the link 2 prior to sending the first processed facsimile control signal 5. Thereafter, the first facsimile control signal 5 processed by the facsimile control signal processing function unit 1 is transmitted.

In the link 2, the initial signal discrimination function unit 2
Since the first signal to arrive at is a processed signal, the initial signal determination function unit 2 of the link 2 determines that the signal is a processed signal. If it is determined that the signal is a processed signal, the facsimile control signal processing function unit 1 is not activated. Therefore, the first processed facsimile control signal 5 transmitted after the processed signal is sent to the facsimile terminal F2 directly connected to the link 2 without being processed to guarantee the standard protocol operation. As a result, in the link 2, the processed first facsimile control signal 5 is transparently transmitted and sent to the facsimile terminal F2.

As described above, in the facsimile signal transmission system according to the embodiment of the present invention, the initial signal discrimination function unit 2 is connected to the link directly connected to the facsimile terminal F.
And a processed signal sending function unit 3. Starting of the facsimile control signal processing function unit 1 is controlled based on the signal that arrives first in the initial signal determination function unit 2, and transmission of the processed signal from the processed signal transmission function unit 3 is controlled. When the first signal reaching the initial signal discriminating function unit 2 on the link (link 1) on the transmitting side is the first facsimile control signal 4, the facsimile control signal processing function unit 1 performs a process for guaranteeing a standard protocol and processes it. The generated first facsimile control signal 5 is generated. In the link (link 2) on the receiving side, the signal that first reaches the initial signal discriminating function unit 2 becomes the processed signal based on the processed signal transmitted on the link on the transmitting side. The control signal 5 is transmitted to the facsimile terminal F without being processed to guarantee the standard protocol. Therefore, the processing for guaranteeing the standard protocol is not performed in the link on the receiving side, so that the transmission time of the facsimile control signal can be shortened.

In the present invention, the processed signal sent from the processed signal sending function section 3 of the facsimile signal transmission system is the same modulation (V.21) as the flag signal sequence as the processed signal.
The bit string that has been used can be used. M for bit string
PN (pseudo noise) signals such as sequences can be used. When a bit string is used as the processed signal, the initial signal judging function unit 2 judges whether the first signal to arrive is a facsimile control signal or a bit string.

Further, in the present invention, a tone signal can be used as the processed signal transmitted from the processed signal transmitting function section 3 of the facsimile signal transmission system. The tone signal has the same modulation (V.
21) has not been done. When a tone signal is used as the processed signal, the initial signal determination function unit 2 determines whether the first signal to arrive is a facsimile control signal or a tone signal of a specific length (time length).

Embodiment 2 of the Invention FIG. 3 is a block diagram showing a schematic configuration of a facsimile signal transmission system according to Embodiment 2 of the present invention. As shown in FIG. 3, in the facsimile signal transmission system according to the embodiment of the present invention, the processed signal sending function unit 3 described in the first embodiment of the invention is the flag signal sending function unit 3.
Further, a detection flag signal length setting unit (detection processed signal length setting unit) 6 is added. In the flag signal sending function unit 3F, a flag signal string is sent as a processed signal. In the detection flag signal length setting unit 6, the signal length of the flag signal sequence to be recognized can be set in advance in consideration of the characteristics of the transmission path between the links.

As described above, in the facsimile signal transmission system according to the embodiment of the present invention, since the detection flag signal length setting unit 6 is added, it is possible to flexibly cope with the construction of the network.

In the present invention, similarly to the first embodiment of the invention described above, a bit string and a tone signal can be used for the processed signal used in the facsimile signal transmission system. When a bit string is used for the processed signal, the processed signal sending function unit 3 is composed of a bit string sending function unit,
Further, a detection bit string length setting unit is added. When a tone signal is used for the processed signal, the processed signal sending function unit 3 is composed of a tone signal sending function unit, and a detected tone signal length setting unit is further added.

[0033]

According to the present invention, it is possible to provide a facsimile signal transmission system in which the transmission time of a facsimile control signal can be shortened and facsimile transmission can be surely realized even if the number of links increases.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a facsimile signal transmission system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a sequence of a facsimile control signal in the facsimile signal transmission system shown in FIG.

FIG. 3 is a block diagram showing a schematic configuration of a facsimile signal transmission system according to a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a facsimile signal transmission system according to a conventional technique.

FIG. 5 is a diagram showing a signal state during network construction according to a conventional technique.

FIG. 6 is a block configuration diagram of a facsimile signal transmission system according to a conventional technique.

7 is a diagram showing a sequence of a facsimile control signal in the facsimile signal transmission system shown in FIG.

[Explanation of symbols]

1 facsimile control signal processing function section, 2 initial signal discrimination function section, 3 processed signal sending function section, 4 first facsimile control signal, 5 processed first facsimile control signal, 3F flag signal string sending function section, 6 detection Flag signal length setting unit.

Claims (3)

[Claims] 1. A facsimile signal transmission system in which a digital transmission device for demodulating and transmitting a facsimile signal is connected over a plurality of links via a repeater exchange to construct a network, wherein a standard protocol operation is added to the facsimile control signal. A facsimile control signal processing function unit for performing a guarantee process, and a processed signal indicating that a facsimile control signal has been processed by the facsimile control signal processing function unit is transmitted prior to the transmission of the processed facsimile control signal. The signal sending function unit determines whether the first arriving signal is the facsimile control signal or the processed signal, and when it is determined to be the facsimile control signal, activates the facsimile control signal processing function unit to set the facsimile control signal to the facsimile control signal. Does the processed signal transmission function unit perform processing An initial signal discrimination function unit that sends a processed signal from the facsimile control signal processing unit, does not activate the facsimile control signal processing function unit when the processed signal is discriminated, and does not perform a process for guaranteeing a standard protocol operation on the facsimile control signal. A facsimile signal transmission system characterized by comprising: 2. The facsimile signal transmission system according to claim 1, wherein the processed signal sending function unit can send either a flag signal string, a bit string, or a tone signal as a processed signal. Signal transmission method. 3. The facsimile signal transmission system according to claim 1 or 2, wherein a processed signal which is connected to the initial signal discrimination function unit and is recognized and a signal length which is recognized by the processed signal are A facsimile signal transmission system characterized by having a detection-processed signal length setting unit that can be set.