JP2002190931A - Communication terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication terminal device for accurately grasping the condition of a line. SOLUTION: Every time data that are received by a modem 17 are subjected to DMA transmission at a DMA section 18 in the case of TCF reception during a facsimile communication procedure, an EQM value is read from the modem 17 and an average value is calculated. Then, it is decided whether the average value is equal to or less than a threshold that is set to a threshold table 21 or not, thus deciding whether modem training by TCF is conforming or not. Since the average value of the EQM value does not vary due to a little noise, the condition of the line can be judged accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal capable of performing facsimile communication.

[0002]

2. Description of the Related Art In facsimile communication, during a procedure, a receiving side notifies a receiving side of a receiving capability by a DIS in a procedure, and then the transmitting side considers the receiving capability of the receiving side and the transmitting capability of the transmitting side. Is provisionally determined and notified to the receiving side by DCS. Thereafter, a training check signal TCF is transmitted from the transmitting side to the receiving side at the provisionally determined communication speed, and the receiving side performs training of the modem, that is, checks whether reception is possible at the communication speed. This result is notified to the transmitting side, and if the receiving side can receive at the communication speed, it is determined that communication is to be performed at the communication speed, and subsequent image transmission is performed. If the receiving side cannot receive at the communication speed, the training is performed by reducing the communication speed or by switching to a communication system that is less affected by the line condition. In this way, the training is performed until the receiving side can receive. With such a training sequence, if the line condition is good, reception can be performed at a high communication speed. If the line condition is bad, communication can be performed at a communication speed and communication method according to the situation at that time. It can be carried out.

[0003] T used in the above training sequence
The CF transmits a continuous “0” from the transmitting side for about 1.5 seconds. This is received by the receiving side, and it is '0' for more than 1 second.
It has been determined that communication at that communication speed is possible if the communication speed can be continuously received. However, even if the condition of the line is good, noise or the like happens to be mixed in the middle of the line, and if any data does not become “0”, the training fails by itself. For this reason, there has been a problem that the communication speed is reduced even when the line condition is almost good.

On the other hand, many modems generally output a value called EYE quality (hereinafter referred to as an EQM value). This EQM value is a deviation amount between a reference position of a signal element arranged on a real-imaginary plane and an actual position of a received signal in differential phase modulation or quadrature amplitude modulation generally used in facsimile communication. Is a value that indicates If this EQM value is small, it indicates that the transmission quality is good. It is possible to grasp the status of the line from the EQM value. But,
In the facsimile communication, the above-described determination method is used, and the EQM value is not used.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a communication terminal device capable of more accurately grasping the status of a line. is there.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a communication terminal capable of facsimile communication, a modem for modulating and demodulating data, a facsimile communication using the modem, and a method for receiving TCF data during a facsimile communication procedure. Control means for detecting an EQM value output from the modem at predetermined time intervals and comparing the detected value with a preset threshold value to determine the status of the line. Thus, for example, even if noise is mixed about once or several times in an almost good line, there is almost no effect,
The condition of the line can be determined to be good, and the condition of the line can be determined more accurately.

[0007] Such a determination of the line status can be made more accurately by detecting the EQM value a plurality of times, calculating the average value, and comparing the average value with the threshold value. In order to detect the EQM value a plurality of times, the configuration is such that the EQM value is detected in conjunction with the process of DMA-transferring the data received by the modem to the memory.
It is possible to easily detect the EQM value a plurality of times without requiring a process such as separately starting a process.

[0008] In addition, a more rigorous determination can be made by judging the state of the line in consideration of whether or not 0s of the received TCF data continue for a predetermined number of data, which is conventionally used.

[0009] The threshold value to be compared with the EQM value can be set according to the communication speed. When the communication method is also changed, a threshold can be set according to the communication method and the communication speed. This makes it possible to make a determination according to the communication speed and further the communication method.

[0010]

FIG. 1 is a block diagram showing an embodiment of a communication terminal device according to the present invention. In the figure, 11 is a main control unit, 12 is a display unit, 13 is an operation unit, 14 is a reading unit,
15 is a recording unit, 16 is an NCU, 17 is a modem, 18 is D
The MA unit, 19 is an image memory, 20 is a RAM, 21 is a threshold table, 22 is a ROM, and 23 is a bus.

The main control unit 11 controls the entire communication terminal device and implements a facsimile communication function and the like via the modem 17 and the NCU 16. At the time of facsimile reception, data transmission / reception is performed with the transmission side in accordance with a predetermined communication procedure.
7 is performed, that is, a process of determining a communication speed and a communication method that can communicate in the current line state is performed. At this time, it is possible to determine whether or not “0” sent by the TCF has been continuously received for one second as conventionally performed. Further, the EQM value output from the modem 17 can be obtained and compared with a predetermined threshold value. Alternatively, it is possible to acquire the EQM value output from the modem 17 a plurality of times, calculate the average value, and compare and determine the average value with a predetermined threshold value. When acquiring the EQM value from the modem 17 a plurality of times, for example,
This can be performed before and after the DMA transfer by the MA unit 18. Then, if the current communication speed allows sufficient reception, the CFR is transmitted to the transmission side, and the process proceeds to reception of image data. If it is determined that the reception cannot be performed at the current communication speed, the FTT is transmitted to the transmitting side to reduce the communication speed or change the communication method to perform the training of the modem 17 again by the TCF.

The threshold value to be compared with the EQM value or the average value of the EQM value can be set according to the communication speed and the communication system. Further, by adjusting the threshold value, it is possible to adjust whether the determination is strict or loose. If the determination is made strictly, the number of determinations that the communication at the current communication speed is difficult is increased, and the communication is performed at a lower communication speed. If the determination is made loosely, the communication at the current communication rate is likely to be performed more frequently. However, the high communication rate is often offset by retransmission due to an error or the like. Such a threshold value is determined, for example, by the RAM2
0 or the like can be stored in advance as a table.

The display unit 12 can display various information such as a message to the user, a message indicating the state of the apparatus, and operation guidance. Operation unit 1
3 allows the user to make various settings and instructions.
At this time, it can be performed while using the display unit 12. For example, in modem training, it may be configured to be able to set whether to judge the state of the line based on the judgment of “0” sent by the TCF and whether to judge it based on the EQM value.

The reading section 14 reads an image on a document to be transmitted under the control of the main control section 11. Reading unit 14
Is arbitrary. Also, when performing only reception or receiving an image to be transmitted from outside, the reading unit 1
It is also possible to configure without providing 4. Recording unit 15
Forms a received image, an image read by the reading unit 14, various kinds of setting information and management information, a message for a user, and the like on a recording sheet under the control of the main control unit 11. The recording method of the recording unit 15 is also arbitrary.
Further, for example, in a configuration in which a received image is output to the outside, the configuration can be such that the recording unit 15 is not provided.

The NCU 16 and the modem 17 communicate with a communication partner device via, for example, a public line or a dedicated line. The NCU 16 controls a line and the like. Also,
The modem 17 modulates and demodulates image data to be transmitted and received.
When receiving data, the modem 17 sends an EQM
It has a function to output a value.

The DMA unit 18 includes an image memory 19 and a RAM.
Data transfer between the modem 20, the modem 17, the reading unit 14, and the recording unit 15 is performed by DMA. For example, data transfer at the time of receiving a TCF and subsequent transfer of image data are performed. The setting of the transfer amount and the like is performed by the main control unit 11. Of course, there may be a configuration in which the DMA unit 18 is not provided.

The image memory 19 can store an image to be transmitted or received, an image read by the reading unit 14, an image being processed, and the like. When storing an image in the image memory 19, the image may be stored in a compressed state.

The RAM 20 is used when it is necessary to store data in the processing of the main control unit 11 and other units.
The data at the time of receiving the TCF can be transferred to the RAM 20 or the image memory 19. Further, the RAM 20 holds a threshold table 21 in which a threshold value to be compared with the EQM value or the average value of the EQM value in the main control unit 11 is stored. FIG. 2 is an explanatory diagram of an example of the threshold table. The threshold table 21 shown in FIG. 2 shows an example in which a threshold value to be compared with the EQM value or the average value of the EQM value can be stored according to the communication speed, the communication method, and the severity of the determination. In the example shown in FIG. 2, the severity of the determination is shown at five levels, and the threshold value at each level is set according to each communication method and communication speed. Of course, the number of levels is arbitrary, and levels need not be provided. The threshold value may be set to a smaller value as the communication speed becomes higher and the determination level becomes stricter so that stricter determination is performed with respect to phase shift and the like. The threshold table 21 may be stored in an area of the RAM 20 that can hold data even when the power is turned off.

The ROM 22 stores a program that defines the operation of the main controller 11, fixed data, and the like. The above-described threshold table 21 may be stored in the ROM 22. Also, if adjustment is required,
Among them, it can be stored in a rewritable area.

The bus 23 includes a main control unit 11, a display unit 12,
Operation unit 13, reading unit 14, recording unit 15, NCU 16, modem 17, DMA unit 18, image memory 19, RAM2
0, ROM 22 and the like are connected to each other to enable data transfer between them. In addition to these, various devices may be connected to the bus 23. Also, for example, an interface is connected to the bus 23, and external devices such as a computer and a printer or LA through the interface.
N or the like.

Next, an example of the operation of the communication terminal device according to the embodiment of the present invention will be described. In one embodiment of the communication terminal device according to the present invention, the process of the modem training at the time of facsimile reception has a feature. Therefore, the process will be described, and other processes will be omitted. FIGS. 3 and 4 are flowcharts showing an example of a modem training operation at the time of image reception in the embodiment of the communication terminal device of the present invention. At the time of facsimile reception, after notifying the receiving side to the transmitting side by DIS,
Communication conditions including a communication speed and the like are instructed by the DCS from the transmission side. Accordingly, in S31, the modem 1
7 is set.

In step S32, a three-second timer, which is a timeout period for receiving the pre-data training signal before receiving the TCF, is started. Then, in S33, it is determined whether or not the pre-data training signal has been transmitted normally. If normal reception of the pre-data training signal is not confirmed, it is determined whether or not 3 seconds have elapsed in S34, and if within 3 seconds, the process returns to S33. If normal reception of the pre-data training signal is confirmed within 3 seconds, S
The processing shifts to the receiving process of the TCF 35 and thereafter. If normal reception of the pre-data training signal is not confirmed within three seconds, it is determined that modem training by the TCF has failed in S52 without checking the data of the TCF.

After normal reception of the pre-data training signal is confirmed, various initializations for receiving the TCF are performed. First, in S35, a two-second timer that specifies the TCF reception and determination time is started. In S36, a one-second timer is started as a time for acquiring the average value of the EQM value in the TCF. This time is also the time for receiving consecutive '0's. S35 and S
36 may be any of them. Of course, it is desirable to be able to set simultaneously.

In step S37, the average EQM value indicating the average value of the EQM value is initialized to 0, and in step S38, the EQM value check status indicating the determination result of the EQM value is initialized to NG. Further, in S39, a data check status indicating whether or not continuous'0's for one second or longer has been detected is initialized to NG.

Further, in step S40, an interrupt process for acquiring the EQM value and sequentially calculating the average value is enabled. This interrupt processing will be described later. Then, in S41, the elapse of one second is waited for by the one-second timer started in S36. During this time, the modem 17 receives the TCF and outputs the EQM value at the time of reception. The TCF data received by the modem 17 is DMA-transferred by the DMA unit 18 to the RAM 20 or the image memory 19. For example, the end of the DMA transfer is used as an interrupt, an interrupt process is started, and the EQM value is obtained from the modem 17. Then, an average value can be calculated.

FIG. 5 is a flowchart showing an example of the interrupt processing. In S61, the EQM value is read from the modem 17. In step S62, the average EQM value is checked. If the value is 0, the first EQM value is read. Therefore, in step S63, the EQM value read in step S61 is set as the average EQM value. If the average of the EQM is not 0 in S62, the average of the EQM and the
The value is added and divided by 2 to obtain a new EQM average value.

As described above, the modem 17 is controlled by the interrupt processing.
The average value is calculated each time the EQM value is read from the. By repeating this process, the EQM value is averaged, and even if the EQM value greatly fluctuates once or several times due to, for example, noise, the EQM value is set as a value that is not affected by the fluctuation.
An average value is obtained.

In this example, the average of the EQM values for one second is obtained, and it is desirable that the number of samples be substantially uniform regardless of the communication speed. Therefore, DMA
In order for the data transfer by the unit 18 to occur at equal intervals,
The amount of data to be transferred by the MA, the activation interval of the DMA unit 18, and the like may be set according to the communication speed. Also,
Variations due to differences in the number of samples can also be adjusted by changing the threshold according to the communication speed.

Returning to FIGS. 3 and 4, after one second has passed, S
At step 42, the operation of the interrupt processing is stopped, and at step S43, the EQM average value is compared with a predetermined threshold value. The threshold is obtained from the threshold table 21 according to the current communication speed, communication method, and the like. When the threshold table 21 is as shown in FIG. 2, a threshold corresponding to a preset level indicating the severity of the determination is acquired along with the current communication speed and communication method, and the EQM value is obtained. Compare with the average value of As a result of the comparison, if the EQM average value is within the threshold,
In the determination using the EQM average value, it is determined that communication at the communication speed (and the communication method) is possible, and the EQM value check status is set to OK in S44. If the EQM average value exceeds the threshold, S44 is skipped and the EQM value check status remains NG.

Next, in S45, the data of the TCF received during the past one second is checked to determine whether or not the data is all "0". This determination is a conventional TCF determination method. If the data check is OK, that is, if the data of the TCF received in one second is all “0”, it is determined in the determination by the data check that communication at the communication speed (and communication method) is possible, and in S46 Set the data check status to OK. If '1' is included in the data received for one second, the determination is continued at this point, S46 is skipped, and the data check status remains NG.

In S47, it is determined whether or not the received data of the TCF exists, and in S48, it is determined whether two seconds have elapsed. Further, in S49, it is determined whether or not the data check status is OK. If the data check status remains NG, there is received data of the TCF.
Is repeatedly performed.
This makes it possible to make a determination based on the TCF data for one second up to the determination time. After the data check status becomes OK, S47 to S4 until TCF reception data is exhausted or two seconds elapse.
9 will wait.

In S50, it is determined whether or not the setting is to use the result of the data check.
At 51, the data check status is determined. If the data check status is NG, it is determined in S52 that modem training by the TCF has failed. If the setting does not use the result of the data check, the process proceeds to the next EQM value check without determining the data check status.

In S53, it is determined whether or not the setting uses the check result of the EQM value. If the setting is to be used, the status of the EQM value check is determined in S54. If the EQM value check status is NG, S
At 52, it is determined that the modem training by the TCF has failed. If the EQM value check status is OK, it is determined in S55 that the training of the modem by the TCF has been successful. If the setting does not use the check result of the EQM value, the EQM value check status is not determined, and it is determined in S55 that the training of the modem by the TCF is successful.

As described above, it is possible to determine the success or failure of the modem training by using the average value of the EQM value. Therefore, for example, the line condition is good, and the TCF data for one second happens to be affected by noise or the like. Even in the case where “1 ′” is included, it is possible to perform image transmission at a higher communication speed with successful modem training. In addition, the success or failure of the modem training can be determined by using the data check that has been conventionally performed together with the average value of the EQM value, thereby making it possible to determine the line more strictly.

The setting of whether or not to use the result of the data check and the setting of whether or not to use the check result of the EQM value must be set to use at least one of them. Of course, it may be set to use both.

In the above-described example of the operation, the calculation of the EQM average value is one second. However, the present invention is not limited to this. Etc. can be set. Further, other statistical methods may be used in addition to the average, such as further considering the variance. Of course E
It is also possible to compare the QM value with a threshold value without averaging the QM value.

Further, in the above-described example, the EQM value is read by using the DMA transfer as a trigger. However, the present invention is not limited to this. Good. However, if processing such as reading of the EQM value is performed by another processing, the processing as a whole becomes complicated. Therefore, the processing such as reading of the EQM value at the time of DMA transfer is simplified as described above. can do.

[0038]

As is clear from the above description, according to the present invention, the EQM value output from the modem,
Since the pass / fail of the modem training is determined by using the average value of the QM value, the modem training does not fail due to the noise which happens to be mixed and the communication speed is not reduced, and more accurate line evaluation can be performed. Needless to say, a more strict evaluation of the line can be performed by using the conventional detection of "0" data of the TCF. Also, the EQM value or EQM
The threshold value used to determine the average value can be set according to the communication speed, the communication method, the severity of the determination, and the like, and the evaluation can be performed finely. According to the present invention, various effects are obtained as described above.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a communication terminal device of the present invention.

FIG. 2 is an explanatory diagram of an example of a threshold table.

FIG. 3 is a flowchart showing an example of a modem training operation at the time of image reception in the embodiment of the communication terminal device of the present invention.

FIG. 4 is a flowchart (continued) illustrating an example of a modem training operation at the time of image reception in the embodiment of the communication terminal device of the present invention.

FIG. 5 is a flowchart illustrating an example of an interrupt process.

[Explanation of symbols]

11: Main control unit, 12: Display unit, 13: Operation unit, 14 ...
Reading unit, 15: recording unit, 16: NCU, 17: modem,
18 DMA unit, 19 image memory, 20 RAM, 2
1. Threshold table, 22 ROM, 23 bus.

Claims (4)

[Claims] 1. A communication terminal device capable of facsimile communication, comprising: a modem for modulating and demodulating data; a facsimile communication using the modem; and output from the modem at predetermined time intervals when receiving TCF data during a facsimile communication procedure. A communication terminal device comprising: a control unit that detects an EQM value to be performed and compares the detected EQM value with a preset threshold value to determine a line status. 2. The control means according to claim 1, wherein
The communication terminal device according to claim 1, wherein the communication terminal device detects the value a plurality of times, calculates an average value thereof, and compares the average value with the threshold value. 3. The control means further comprises:
3. The communication terminal device according to claim 1, wherein the status of the line is determined in consideration of whether or not 0 of the F data continues for a predetermined number of data. 4. The communication terminal device according to claim 1, wherein the threshold value is set according to a communication speed.