JPH11289441A - Communication terminal equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication terminal equipment that is able to decide a proper transmission rate of communication. SOLUTION: A receiver side device measures a channel state (band width and S/N) based on line probing signals L1, L2 sent from a transmitter side device. Then the band width and S/N are set to a facsimile information field FIF part in an NSF signal and the resulting signal is sent to the transmitter side device. Then the transmitter side device stores the band width and S/N to a FAX number table 13b. Then the transmitter side device decides a symbol speed from a symbol speed decision table 13c based on the band width. Furthermore, the transmitter side device decides a transmission rate from a transmission rate decision table 13d based on the symbol speed and the S/N. As a result, the transmitter side device grasps in advance a channel state up to a receiver side device being a transmission destination prior to 2nd and succeeding calls. Thus, the transmitter side device can decide a proper transmission rate in advance in response to the channel state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal device represented by a facsimile device, a multifunction device having a copy function and a facsimile function, and more particularly to an ITU.
-T Recommendation V. The present invention relates to a communication terminal device having 34 functions.

[0002]

2. Description of the Related Art Conventionally, in a facsimile apparatus as a communication terminal apparatus, ITU-T Recommendation V. 17 and the like, and modulates the transmission image data in accordance with Recommendation T.17. The image data is transmitted in a facsimile transmission control procedure according to No. 30.

[0003] In recent years, image data has a maximum size of 33.6 [kb].
ps] can be transmitted at a communication speed of V.ps. 3
Facsimile machines having four functions are also becoming popular. This V. If the 34 function is used, it is possible to change the communication speed according to the line condition between the transmitting device and the receiving device. Therefore, when a large amount of image data is transmitted and the line condition is favorable, the communication time can be shortened and the communication fee for the communication can be reduced. In addition, there has conventionally been a facsimile apparatus provided with an ECM mode (error correction function) for reliably transmitting image data. Therefore, V.E. By transmitting the image data in accordance with the 34 functions, the image data can be transmitted to the receiving device more quickly and more reliably.

[0004]

However, this ECM
V. mode When transmission is performed according to the F.34 function, the line condition between the transmitting device and the receiving device deteriorates, and when an error frame occurs, a signal indicating a retransmission request is transmitted from the receiving device to the transmitting device. Is done. Then, the transmitting device retransmits the image data of the error frame to the receiving device. In addition, if the line conditions worsen,
The communication speed is reduced, and the image data of the erroneous frame is retransmitted to the receiving device. As a result, V.V. having a high communication speed is communicated with a receiving device having a poor line condition. Even in the case of communication using the 34 function, retransmission from the transmitting apparatus frequently occurs, and conversely, the communication time is increased and the communication fee is sometimes increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems existing in the prior art, and has as its object to provide a communication terminal device capable of determining an appropriate communication speed in advance. Is to do.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a bandwidth and a signal / noise ratio are determined based on a line condition determination signal transmitted from a transmitting apparatus. , And control means for transmitting the bandwidth and the signal / noise ratio detected by the detecting means to the transmitting device.

According to the second aspect of the present invention, a storage means for receiving information including a bandwidth and a signal / noise ratio transmitted from a receiving side device and storing the received information in correspondence with each destination. With.

According to a third aspect of the present invention, in the communication terminal device according to the second aspect, the communication speed is determined based on the bandwidth and the signal / noise ratio stored in the storage means, and the transmission speed is determined for each transmission destination. Control means for making a call.

In the embodiments of the invention described below, the "communication terminal device" described in the claims or the means for solving the problems corresponds to the facsimile apparatus 1, and the "detection means" also corresponds to the modem. 20. Similarly, the “control means” includes the MPU 11, the ROM 12, and the RAM 13
Is equivalent to

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a facsimile device 1 as a communication terminal device includes an MPU 1
1, ROM 12, RAM 13, reading unit 14, recording unit 1
5, an operation unit 16, a display unit 17, an image memory 18, a codec 19, a modem 20, and an NCU 21. Each of the units 11 to 21 is connected via a bus 22.

The MPU 11 controls each part of the facsimile machine 1. The ROM 12 stores a program for controlling the facsimile machine 1. RAM 13
Temporarily stores various information on the facsimile machine 1. The RAM 13 has a retransmission count storage area 13a for temporarily storing the number of retransmissions. Further, R
AM13, as shown in FIG. 2, "abbreviated number", "FA
FAX number table 13b composed of items of "X number", "bandwidth (L: cut-off frequency on low frequency side, H: cut-off frequency on high frequency side)", "S / N ratio", and "number of retransmissions" Is stored. In addition, as shown in FIG. 3, the RAM 13 stores a symbol rate composed of items of “bandwidth (L: lower cutoff frequency, H: higher cutoff frequency)” and “symbol rate”. The decision table 13c is stored. Also, RAM
13 stores a communication speed determination table 13d including "S / N ratio" and "communication speed", as shown in FIG. The “bandwidth” and “S / N” shown in FIGS.
"H" added after the data in the item of "ratio" is 1
Indicates a hexadecimal number. Further, the symbol rate determination table 13c shown in FIG. 3 and the communication rate determination table 13d shown in FIG.
Is a value determined by experiment.

The reading section 14 reads image data on a document and outputs black and white binary image data. The recording unit 15 is composed of an electrophotographic printer, and records received image data and image data of a document read by the reading unit 14 on recording paper in a copy operation.

The operation unit 16 includes a numeric keypad (including the * and # keys) 16a for inputting a telephone number and the like, an abbreviated number registration, and an abbreviated key 16b for transmitting from the abbreviated number.
Start key 1 for starting document reading operation
6c, a communication / copy key 16d for setting a "communication (FAX)" operation or a "copy" operation, a communication mode key 16e for setting a communication mode to an "ECM mode" or a "non-ECM mode", etc. It has operation keys. A display unit 17 such as an LCD displays various information such as an operation state of the facsimile machine 1.

The image memory 18 temporarily stores received image data and image data read by the reading unit 14 and subjected to MMR compression encoding by the codec 19. Codec 19
Encodes the image data read by the reading unit 14 for transmission by MH, MR, MMR, or the like. The codec 19 decodes the received image data.

The modem 20 conforms to ITU-T Recommendation T.30. 30 based on a facsimile transmission control procedure according to ITU-
T Recommendation V. 17, V. 27ter, V.A. 29 etc.
V. 17), and modulates and demodulates the transmission / reception data in accordance with any one of the above. Also, the modem 20 conforms to ITU-T Recommendation V. 8 and a session start procedure according to ITU-T Recommendation V.8. 34, and modulates and demodulates transmission / reception data. Further, the modem 20 has a function of performing communication according to an ECM mode (error correction function) and a non-ECM mode. In addition, the modem 20 outputs to the MPU 11 the cutoff frequency on the low band side and the cutoff frequency on the high band side in the bandwidth, and the S / N ratio.

The NCU 21 has a function of controlling connection with the telephone line L and detecting transmission and reception of a dial signal corresponding to the fax number of the other party. In the facsimile apparatus 1 configured as described above, the operation when transmitting using the ECM mode will be described.
As shown in FIG. 8 and V.I. The operation will be described with reference to the flowcharts shown in FIGS. In this flowchart, operations other than the user are executed under the control of the MPU 11 based on a program stored in the ROM 12.
Prior to the processing of this flowchart, it is assumed that the user operates the communication / copy key 16d to set “communication mode” and the communication mode key 16e to set “ECM mode”. .

As shown in FIG. 6, in S1, a user places a document on a document table (not shown) of the reading unit 14. In S2, the user sets the destination FA
The X number is the numeric keypad 16a of the operation unit 16 or the shortcut key 1
6b.

In S3, the user waits for the start key 16c to be pressed. In S4, the value of the retransmission count storage area 13a is cleared.

In step S5, the document is read by the reading unit 14, and the image data of the read document is encoded by the codec 19. Then, the encoded image data is stored in the image memory 18.

In S6, the content of each item corresponding to the destination FAX number input in S2 is F
It is determined whether or not it is registered in the AX number table 13b. If the contents of each item are registered in the FAX number table 13b, the process proceeds to S7. On the other hand, if the content of each item is not registered in the FAX number table 13b, it is determined that the FAX number has not been transmitted in the past, and the process shifts to S11 shown in FIG.

In S7, based on the bandwidth corresponding to the FAX number of the destination input in S2,
The symbol rate is determined from the symbol rate determination table 13c. Specifically, for example, when the abbreviated number “0” is input in S2, the FAX number table 13b
Is L: 01H and H: 26H, the bandwidth L: 0 of the symbol rate determination table 13c is
0H, H: corresponds to the case of 26H, and the symbol rate is 34
29 [baud] is determined.

In S8, the symbol rate determined in S7 and the FAX input in S2 are used.
The communication speed is determined from the communication speed determination table 13d based on the S / N ratio for the number. Specifically, since the symbol rate is 3429 [baud] in the previous example, it corresponds to the communication rate determination table 13d in the case of the symbol rate 3429 [baud]. Also, S / N
Since the ratio is 16H [dB], the table 13d
Corresponds to 17H to 19H [dB], and the communication speed is determined to be 24.0 [kbps].

In S9, it is determined whether or not the number of retransmissions corresponding to the FAX number of the destination input in S2 is "0". When the number of retransmissions is “0”, the process proceeds to S11 shown in FIG. On the other hand, if the number of retransmissions is other than “0”, the process proceeds to S10. Specifically, in the previous example, since the number of retransmissions is “1”, the process shifts to S10.

In S10, the communication speed is reduced by one rank. That is, at the communication speed obtained from the bandwidth and the S / N ratio of the FAX number table 13b, retransmission has occurred during the previous transmission. Therefore, in this transmission, the transmission is performed at a communication speed reduced by one rank in advance in order to minimize the occurrence of retransmission. Specifically, in the previous example, the communication speed was 24.0 [kbps].
To 14.4 [kbps].

At S11 shown in FIG. 7, a call is made to the FAX number input at S2.
Specifically, a call signal (CNG signal or CI signal, etc.)
Is sent to the exchange.

In S12, the NCU 21 waits for the line L to be connected to the exchange. S13
In, the reception of the ANSam signal (modified response tone) transmitted from the receiving side device is awaited until the predetermined time elapses.

At S14, a CM signal (calling menu signal) is transmitted to the receiving device. In S15, the reception of the JM signal (common menu signal) transmitted from the receiving side device is waited until the predetermined time elapses.

In S16, a CJ signal (CM termination signal) is transmitted to the receiving device. In S17, the reception of the INFO0a signal transmitted from the receiving side device is waited until the predetermined time elapses. Here, the INFO sequence (INFO0a signal, INF
The O0c signal and the INFOh signal) are used to exchange modem capabilities, line probing results, and data mode modulation parameters.

In S18, the tone A signal and the tone A phase inverted signal are detected. Here, the tone A is a tone of 2400 [Hz], and the tone A phase inversion signal is obtained by inverting the phase of the tone A by 180 degrees.

In S19, when a predetermined silence period has elapsed, an INFO0c signal is transmitted to the receiving device.
Here, in the INFO0 sequence, the symbol rate of the transmitting apparatus is notified to the receiving apparatus. If the symbol rate is determined in advance from the bandwidth and the S / N ratio at the previous transmission in S7, INFO0c is used.
The information indicating the ability at or below the symbol rate determined by the signal is
The receiving device is notified. On the other hand, when the bandwidth and the S / N ratio at the time of the previous transmission are not stored in the FAX number table 13b, the symbol rate of the highest capability originally possessed by the transmitting apparatus is notified to the receiving apparatus. The receiving device does not select a symbol rate that exceeds the symbol rate indicated by the INFO0c signal received from the transmitting device.

In S20, the tone B signal and the tone B phase inverted signal are transmitted to the receiving device. here,
The tone B is a 1200 [Hz] tone, and the tone B phase inversion signal is obtained by inverting the phase of the tone B by 180 degrees.

In S21 shown in FIG. 8, L1, L2
A signal (line probing signal as a line status determination signal) is transmitted to the receiving device. Here, the line probing signal is called a probing tone.
150 [Hz] from 0 [Hz] to 3750 [Hz]
Notch (However, 900, 1200, 1800, 2400
[Except for [Hz]) and tones whose phases are appropriately set are sequentially changed from 150 [Hz], and are repeatedly transmitted 24 times during 160 [ms]. That is, the line probing signal is transmitted from the transmitting device to the receiving device via the line L. That is, by receiving this signal at the receiving device,
The characteristics of the line L are measured at the receiving device.

In S22, the reception of the tone A signal transmitted from the receiving side device is waited until the predetermined time elapses. In S23, the tone B signal is transmitted to the receiving device.

In S24, the reception of the INFOh signal transmitted from the receiving side device is waited until the predetermined time elapses. That is, the symbol rate indicated by the 27th bit to the 29th bit in the INFOh signal is received.

In S25, the S signal, the S inverted signal,
The PP signal and the TRN signal are transmitted to the receiving device. S
In 26, transmission and reception of the PPh signal, the ALT signal, and the MPh signal are performed with the receiving side device. And M
In exchanging Ph signals, the communication speed between transmission and reception is determined.

In S27, transmission and reception of the E signal are performed with the receiving side device. In S31 shown in FIG. 9, the reception of the NSF signal, the CSI signal, and the DIS signal transmitted from the receiving apparatus is waited until the predetermined time elapses.

In S 32, the bandwidth and S / N ratio indicated by the FIF (Facsimile Information Field) area in the received NSF signal are stored in the FAX number table 13.
b. That is, the bandwidth and S / N ratio are FA as data for determining the communication speed at the next transmission.
It is stored in the X number table 13b.

In S33, the NSS signal, the TSI signal, and the DCS signal are transmitted to the transmitting device. In S34, one block of image data is transmitted to the receiving device according to the ECM mode.

In S35, the PP from the receiving side device is
It is determined whether an R signal (partial page request) has been received. That is, it is determined whether a retransmission error has occurred and a retransmission request has been issued from the receiving device. If a PPR signal has been received, the process proceeds to S36. On the other hand, when the PPR signal has not been received, the process proceeds to S38.

In S36, the retransmission count storage area 13
The value of a is incremented. In S37, the image data of the frame specified by the PPR signal is retransmitted from the receiving device to the receiving device. That is, S35 to S37 until the PPR signal is no longer received from the receiving device.
Is repeatedly executed.

In S38, it is determined whether or not the image data of the next block exists in the image memory 18. If there is image data of the next block, the process proceeds to S39. on the other hand,
If there is no image data of the next block, the process proceeds to S40.

In S39, the PPS-MPS signal is transmitted to the receiving device. In S40, the PPS-
The EOP signal is transmitted to the receiving device. In S41, the DCN signal is transmitted to the receiving side device, and N
The line L to the exchange is released by the CU 21.

In S42, the retransmission count storage area 13
The value of “a” is stored in the item of “number of retransmissions” in the FAX number table 13b. Next, in the facsimile apparatus 1, the operation when receiving using the ECM mode will be described.
As shown in FIG. 8 and V.I. The operation will be described with reference to the flowcharts shown in FIGS. The operation of this flowchart is based on a program stored in the ROM 12 and
It is executed under the control of the PU 11.

In S51, it is waited for the NCU 21 to detect the call bell signal from the exchange based on the call origination in the transmitting apparatus. In S52, NCU2
1 closes the line L to the exchange.

In S53, the ANSam signal is transmitted to the transmitting device. In S54, the CM transmitted from the transmitting apparatus before the predetermined time elapses.
Wait for the signal to be received.

In S55, the JM signal is transmitted to the transmitting device. In S56, the reception of the CJ signal transmitted from the transmitting apparatus is waited until the predetermined time elapses.

In S57, the INFO0a signal is transmitted to the transmitting device. In S58, the I-mail transmitted from the transmitting device before the predetermined time elapses.
Wait for the NFO0c signal to be received.

In S59, the tone B signal and the tone B phase inverted signal are detected. In S60, the tone A signal and the tone A phase inverted signal are transmitted to the transmitting device.

In S61 shown in FIG. 11, the reception of the L1 and L2 signals transmitted from the transmitting apparatus is waited until the predetermined time elapses. In S62, the tone A signal is transmitted to the receiving device.

In S63, the reception of the tone B signal transmitted from the transmitting apparatus is waited. S6
At 4, the modem 20 reads the bandwidth and the S / N ratio of the measurement results of the L1 and L2 signals received at S61.

In S65, the INFOh signal is transmitted to the transmitting device. Specifically, the symbol rate is determined based on the bandwidth read in S64 and the symbol rate determination table 13c. Then, the determined symbol rate is equal to the 27th symbol in the INFOh signal.
The bit is stored in the 29th bit and transmitted to the transmitting device.

In S66, the reception of the S signal, the S inversion signal, the PP signal, and the TRN signal is waited until the predetermined time elapses. In S67, PP
The transmission and reception of the h signal, the ALT signal, and the MPh signal are performed with the transmission side device. Then, in the exchange of the MPh signal, the communication speed between transmission and reception is determined.

In S68, transmission and reception of the E signal are performed with the receiving side device. In S71 shown in FIG. 12, the bandwidth and S / N read in S64 are read.
The ratio is stored in the FIF area in the NSF signal.

In S72, the NSF signal, the CSI signal and the DIS signal are transmitted to the transmitting device. In S73, the NSF signal, the TSI signal, and the DCS signal transmitted from the transmitting apparatus before the predetermined time elapses.
Wait for the signal to be received.

In S74, the CFR signal is transmitted to the transmitting device. In S75, one block of image data is received. In S76, it is determined whether or not there is an error frame in the image data for one block received in S75. If there is an error frame in the image data for one block, the process proceeds to S77. On the other hand, if there is no error frame in the image data for one block, the process proceeds to S79.

In S77, the FIF in the PPR signal
The information of the error frame is stored in the area and transmitted to the transmission side device. In S78, the image data of the retransmission frame transmitted from the transmitting device is received.

In S79, it is determined whether the PPS-MPS signal transmitted from the transmitting device has been received. If a PPS-MPS signal has been received, S7
Returning to 5, the image data for the next one block is received. On the other hand, if no PPS-MPS signal is received,
The process moves to S80.

In S80, the PPS-MP transmitted from the transmitting side device until the predetermined time elapses.
Wait for the S signal to be received. In S81,
Until the predetermined time elapses, the reception of the DCN signal transmitted from the transmitting apparatus is waited. Then, when the DCN signal is received, the line L to the exchange is released by the NCU 21.

As described above, according to the present embodiment, the following operations and effects can be obtained. (1) The line conditions (bandwidth and S / N ratio) are measured at the receiving side device based on the line probing signals (L1, L2) transmitted from the transmitting side device. Then, the bandwidth and the S / N ratio are stored in the FIF area in the NSF signal and transmitted to the transmitting device. In the transmitting device, the bandwidth and the S / N ratio are stored in the FAX number table 13.
b. Therefore, the transmitting apparatus determines the symbol rate from the symbol rate determination table 13c based on the bandwidth. Also, the symbol rate and S / N
The communication speed is determined from the communication speed determination table 13d based on the ratio. As a result, the transmitting device can grasp the line status to the receiving device, which is the transmission destination, before the second and subsequent calls. Therefore, an appropriate communication speed can be determined in advance according to the line condition.

(2) In addition, the bandwidth and the S / N ratio are stored in the FAX number table 13b corresponding to the FAX number of the transmission destination. For this reason, it is possible to grasp the line status for each receiving-side device that is the transmission destination. Therefore, an appropriate communication speed can be determined in advance for each transmission destination.

(3) Further, the transmitting apparatus can lower the communication speed by one rank before transmitting based on the number of retransmissions in the FAX number table 13b. For this reason, the possibility of frequent retransmissions can be minimized. Therefore, the communication time can be shortened and the communication fee can be reduced.

(4) The symbol rate is determined based on the bandwidth output from the modem 20. Then, the communication speed is determined based on the S / N ratio output from the modem 20 and the symbol speed. For this reason, even if the symbol rates are the same but the symbol rates are different, an appropriate communication rate can be reliably determined.

The above embodiment can be modified and embodied as follows. In the above embodiment, transmission / reception is performed in place of the configuration in which the measurement result (bandwidth and S / N ratio) at the time of the line probing signal is transmitted from the reception device to the transmission device, and the measurement result is stored in the transmission device. It may be configured to store the communication speed thus set.

The maximum communication speed transmitted and received between the transmitting device and the receiving device may be stored. In the above embodiment, the measurement result at the time of the line probing signal is stored in the transmitting device. At 34, the communication speed can be changed during communication. For this reason, a configuration may be adopted in which the maximum communication speed during communication is stored in the transmitting device for the next transmission. With this configuration, the next initial communication speed can be started from the previous maximum communication speed. As a result, the communication time can be further reduced, and the communication fee can be reduced.

The above embodiment is described in V. It may be applied to the case of full-duplex communication in 34 functions. In the above-described embodiment, the communication speed is determined based on the bandwidth and the S / N ratio. If the number of retransmissions is one or more, the communication speed is reduced by one rank. , The communication speed may be determined only from the bandwidth and the S / N ratio.

Symbol rate determination table 1 shown in FIG.
3c and the communication speed determination table 13d shown in FIG. 4 may be configured to be stored in the ROM 12 because they are invariant experimental values.

Further, technical ideas other than the claims grasped from the above embodiment will be described below together with their effects. [1] The communication terminal device according to claim 1, wherein the control means stores the highest communication speed performed between the transmitting device and the receiving device.

With this configuration, transmission can be started at the highest communication speed of the last communication. [2] The communication terminal device according to claim 3, wherein the control means determines the communication speed in accordance with the presence or absence of the number of retransmissions in the previous communication.

With this configuration, the communication speed can be determined in consideration of the presence or absence of the number of retransmissions at the time of the last communication. Therefore, a more appropriate communication speed can be determined.

[0070]

Since the present invention is configured as described above, it has the following effects. According to the first aspect, an appropriate communication speed can be determined in advance.

According to the second aspect of the invention, an appropriate communication speed can be determined in advance for each destination. According to the invention described in claim 3, in addition to the effect of the invention described in claim 2, communication time can be shortened, and
Communication charges can also be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a facsimile apparatus according to an embodiment.

FIG. 2 is an explanatory diagram showing a FAX number table.

FIG. 3 is an explanatory diagram showing a symbol rate determination table.

FIG. 4 is an explanatory diagram showing a communication speed determination table for each symbol speed.

FIG. 8 and V.I. Explanatory drawing showing the communication operation in 34.

FIG. 6 is a flowchart showing an operation when transmitting using the ECM mode.

FIG. 7 is a flowchart showing an operation when transmitting using the ECM mode.

FIG. 8 is a flowchart showing an operation when transmitting using the ECM mode.

FIG. 9 is a flowchart showing an operation when transmitting using the ECM mode.

FIG. 10 is a flowchart showing an operation when receiving using the ECM mode.

FIG. 11 is a flowchart showing the operation when receiving using the ECM mode.

FIG. 12 is a flowchart showing the operation when receiving using the ECM mode.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Facsimile machine as a communication terminal device, 11 ... MPU which comprises a control means, 12 ... R which comprises a control means
OM, 13 ... RAM constituting storage means and control means,
20: Modem as detecting means.

Claims (3)

[Claims] 1. A detecting means for detecting a bandwidth and a signal / noise ratio based on a line condition determination signal transmitted from a transmitting apparatus, and a detecting means for detecting a bandwidth and a signal / noise ratio detected by the detecting means. A communication terminal device comprising: a control unit that transmits the information to the device. 2. A communication terminal device comprising: storage means for receiving information including a bandwidth and a signal / noise ratio transmitted from a receiving device, and storing the received information in association with each destination. 3. The communication terminal device according to claim 2, further comprising: a control unit that determines a communication speed based on the bandwidth and the signal / noise ratio stored in the storage unit and makes a call for each transmission destination. Communication terminal device provided.