JP2000244679A - Communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain communication terminal where the distortion of a transmission/ reception signal in a line route between a self device and an opposite party device is optimally corrected and communication quality is improved by selecting a combina tion by which a communication signal is optimally corrected and setting a transmission/ reception equalizer to the selected characteristics. SOLUTION: A transmission side monitors whether equalizer information of the opposite party device is received or not. When it is received, received equalizer information of the opposite party device is stored in RAM (103), which is collated with that of a self device that is previously stored in a ROM, and the combination of the characteristics of the transmission/reception equalizer, by which the line characteristics is optimally compensated, is selected (105). When the selected combination of the transmission/reception equalizer characteristics is reported to the reception side by the transmission side (106), the characteristics of the transmission/reception equalizer of the self device is set in the combination, which is reported from the transmission side, at the reception side (204). In the meantime, the transmission side also sets the characteristics of the transmission/reception equalizer of one's own device in the selected combination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal apparatus such as a facsimile apparatus, and more particularly to a transmission and reception equalizer for correcting distortion in a line path of a transmission / reception signal exchanged by a modem with a partner machine via a line. The present invention relates to a communication terminal device provided with:

[0002]

2. Description of the Related Art Conventionally, when a transmitting device and a receiving device both have a transmission and reception equalizer for correcting transmission and reception signals of a modem, respectively, the transmission and reception equalizers have no relation to the setting of the characteristics of the transmission and reception equalizers at the partner device. , The characteristics of its own transmission and reception equalizers are set.

[0003]

Therefore, both the transmitting side and the receiving side set the characteristics of their own transmission / reception equalizers independently of the settings of the other device, and tried to correct the distortion of the transmission / reception signal generated on the line path. In such a case, the correction may be overcorrected, or the correction may be insufficient, and as a result, it may not be possible to correct the distortion of the transmission / reception signal on the line path, and communication may not be performed normally. There was a problem.

[0004] The present invention has been made in view of the above circumstances, and a communication terminal device capable of optimally correcting distortion of a transmission / reception signal on a line path between the own device and a partner device and improving communication quality. The purpose is to provide.

[0005]

According to a first aspect of the present invention, there is provided a communication terminal apparatus for performing communication by transmitting / receiving a signal to / from a partner apparatus via a line using a modem. A communication terminal device comprising: a transmission equalizer that corrects a signal from a modem with predetermined characteristics and transmits the signal to the partner device; and a reception equalizer that corrects a signal from the partner device with predetermined characteristics and causes the modem to receive the signal. A self-characteristic storage means for storing information on equalizer characteristics which can be set for the own equipment in advance, and an equalizer characteristic of the own equipment stored in the self-characteristic storage means prior to the start of communication with the partner device. Self-device characteristic notifying means for notifying the other device of the information of the other device, and a counterpart device characteristic recognizing device for recognizing information of an equalizer characteristic which can be set by the other device notified from the other device prior to the start of communication. From among the combinations of the equalizer characteristics that can be set in the partner device recognized by the partner device characteristic recognizing means and the equalizer characteristics that can be set in the own device stored in the own device characteristic storage unit, the correction of the communication signal is performed. Characteristic selecting means for selecting an optimum combination, and characteristic setting means for setting the transmission and receiving equalizers to the characteristic selected by the characteristic selecting means.

According to a second aspect of the present invention, in the communication terminal apparatus according to the first aspect, a test is performed by setting a characteristic of the transmission / reception equalizer by the characteristic setting means and then transmitting a test signal to the other terminal by the modem. It further comprises a signal transmitting means and a setting confirming means for receiving a test signal from a partner device by the modem and confirming the effect of the correction by the transmission / reception equalizer.

According to a third aspect of the present invention, in the communication terminal device according to the second aspect, as a result of the confirmation by the setting confirmation unit, the characteristics of the transmission / reception equalizer selected by the characteristic selection unit are insufficiently corrected. In this case, an equalizer characteristic that can be set in the counterpart device recognized by the counterpart device characteristic recognition means and an equalizer characteristic that can be set in the own device stored by the own device characteristic storage means, among other combinations. And a characteristic reselecting unit for selecting a combination that optimizes communication signal correction, and a characteristic resetting unit for setting a transmission / reception equalizer to the characteristic selected by the characteristic reselecting unit.

According to a fourth aspect of the present invention, in the communication terminal device of the second aspect, as a result of the confirmation by the setting confirmation unit, the characteristic of the characteristic selection unit or the transmission / reception equalizer reselected by itself is corrected. Is insufficient, an equalizer characteristic that can be set in the counterpart device recognized by the counterpart device characteristic recognizing means and an equalizer characteristic that can be set in the own device stored in the own device characteristic storage means, and other combinations. A characteristic reselecting unit that selects a combination that optimizes the communication signal correction, a characteristic resetting unit that sets the transmission / reception equalizer to the characteristic selected by the characteristic reselecting unit, and a characteristic resetting unit. After resetting the characteristics of the transmission / reception equalizer, a test signal is retransmitted by the modem, and the transmission / reception equalizer is transmitted to the setting confirmation means of the partner device. And further comprising a test signal retransmission means for re-check the effect of correction by Isa.

According to a fifth aspect of the present invention, in the communication terminal device of the first, second, third, or fourth aspect, the communication started after setting the combination of the characteristics of the transmission / reception equalizer ends normally. If not, an equalizer characteristic that can be set in the counterpart device recognized by the counterpart device characteristic recognizing means and an equalizer characteristic that can be set in the own device stored by the own device characteristic storage means, and other combinations of From among them, a post-communication characteristic reselecting unit that selects a combination that optimizes communication signal correction, a post-communication characteristic resetting unit that sets the transmission / reception equalizer to the characteristic selected by the characteristic reselecting unit, After the setting by the characteristic resetting means, the communication is re-executed.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described in detail.

First, FIG. 1 shows a block configuration of a facsimile apparatus 1 as a communication terminal apparatus according to an embodiment of the present invention.

In FIG. 1, a facsimile apparatus 1 includes a system control unit 2, a ROM 3, a RAM 4, a scanner 5, a plotter 6, an encoding / decoding unit 7, an operation display unit 8, a modem 9, a modem interface unit 10, a network control unit. 11 and a system bus 12.

The system control section 2 controls each section of the apparatus according to the control program written in the ROM 3 while using the RAM 4 as a work area. RO
As described above, M3 is a read-only memory that stores a control program for the system control unit 2 to control each unit of the device. The RAM 4 is a random access memory used as a work area of the system control unit 2 as described above.

The scanner 5 has 3.85 lines / mm, 7.7
This is for obtaining image information by reading a document image at a predetermined reading line density such as book / mm and 15.4 book / mm. The plotter 6 is for recording and outputting the received image information according to its line density, and for recording and outputting (copying operation) the image information read by the scanner 5 according to its line density.

The encoding / decoding unit 7 converts the transmission image data into
While encoding and compressing with a predetermined coding method such as an MH coding method, an MR coding method, and an MMR coding method conforming to G3 facsimile, the received image data is subjected to an MH coding method.
The decoding is performed by a predetermined decoding method corresponding to the MR coding method, the MMR coding method, or the like.

The operation display unit 8 is provided with a numeric keypad for designating a destination telephone number, a transmission start key, a one-touch dial key, and various other keys. It displays the operating state of the device to be notified and various messages.

The modem 9 is a G3 facsimile modem.
It modulates data to be transmitted to the line 20 which is an analog telephone line network via the network control unit 11, and demodulates a signal received from the line 20 via the network control unit 11. Also, the modem 9 has a DTM corresponding to the dialed number.
It also sends out the F signal. The network control unit 11 is connected to the line 20 to close / release the DC loop of the line, detect the polarity reversal of the line, detect the line release, detect a dial tone, detect a tone signal such as a busy tone, and call. It controls connection to a line such as signal detection and generates dial pulses.

The modem interface unit 10 intervenes between the modem 9 and the network control unit 11 to correct the level and characteristics of signals transmitted and received by the modem 9 to optimize the signals input to and output from the modem 9. It is for keeping. The system bus 12 is a signal line through which the above components exchange data.

FIG. 2 shows the configuration of the modem interface unit 10.

In FIG. 1, a transmission / reception signal of a line 20 connected via a network control unit 11, a transmission signal inputted to a 2-wire / 4-wire conversion circuit 30, and a 2-wire / 4-wire conversion circuit 30 Is separated or combined with each other by the two-wire / four-wire conversion circuit 30. The transmission signal from the modem 9 is input to the transmission equalizer 31 and is corrected by the characteristics of the transmission equalizer 31 so that the transmission amplifier Tx
The transmission gain is adjusted by the
Is input as a transmission signal. On the other hand, the reception signal from the two-wire / four-wire conversion circuit 30 is adjusted in reception gain by the reception amplifier Rx, corrected by the characteristics of the reception equalizer 32, and input to the modem 9 as a reception signal.

The transmission equalizer 31 is connected to the system bus 12
Switches SW1a and 1b, which are switched to the contacts a, b, or c in conjunction with each other by the system control unit 2 via the control unit 2; It is composed of a characteristic 1 transmission equalizer 31b connected to each contact b and a characteristic 2 transmission equalizer 31c connected to each contact c. As a result, the transmission equalizer 31
As shown in FIG. 3, the characteristic 0 and the characteristic 1 correspond to the connection contacts a, b and c of the switches SW1a and 1b, respectively.
And characteristic 2 can be varied.

The reception equalizer 32 is connected to the system bus 12
Switches SW2a and 2b, which are switched to the contacts a, b or c in conjunction with each other by the system control unit 2 via the control unit 2; It is composed of a characteristic B reception equalizer 32b connected to each contact b and a characteristic C reception equalizer 32c connected to each contact c. As a result, the reception equalizer 32
As shown in FIG. 4, the characteristic A and the characteristic B correspond to the connection contacts a, b and c of the switches SW2a and 2b, respectively.
And the characteristic C.

Characteristic 0, characteristic 1 and characteristic 2 of the transmission equalizer 31, or characteristic A and characteristic B of the reception equalizer 32
And the characteristic C are differences in gain characteristics for each frequency component, phase compensation characteristics for each frequency component, and the like. The facsimile apparatus 1 stores information on the equalizer characteristics of its own device as shown in FIG. Is stored in the storage area 3a of the ROM 3 in advance.

As shown in FIG. 6, the transmission / reception processing procedure when the facsimile apparatus 1 having the above configuration communicates via the line 20 as the transmitting facsimile apparatus 1a and the receiving facsimile apparatus 1 will be described with reference to FIGS. This will be described with reference to FIG.

First, in FIG. 7, while the receiving side monitors whether there is an incoming call (No loop of decision 201), when the transmitting side calls the receiving side (process 101), the receiving side decision 201 If the answer is Yes, the line path with the transmitting side is connected, and the equalizer information 3a of the own device stored in advance in the ROM 3 as shown in FIG. The transmitting side is notified by a non-standard function setting signal NSS of 30 procedures (process 202). After the process 202, the receiving side monitors whether there is a notification from the transmitting side of the combination of the characteristics of the transmission / reception equalizer (No loop of the determination 203).

On the other hand, after the process 101, the transmitting side monitors whether or not to receive the equalizer information of the partner device (decision 10).
(No loop of No. 2), upon reception (Ye of decision 102)
s), and stores the received equalizer information of the partner device in the storage area 4a of the RAM 4 as shown in FIG.
3) Collating the equalizer information 4a of the partner device with the equalizer information 3a of the own device stored in the ROM 3 in advance, and selecting a combination of transmission and reception equalizer characteristics that can optimally compensate the line characteristics (process 105). ).

The combination of the characteristics of the transmission / reception equalizer that can be selected in the process 105 is, as shown in FIG.
There are nine types: A1, A2, B0, B1, B2, C0, C1, and C2. Note that, for example, the combination A2 means a combination of the characteristic of the reception equalizer 32 with the characteristic A and the characteristic of the transmission equalizer 31 with the characteristic 2.

When the transmitting side notifies the receiving side of the combination of transmission / reception equalizer characteristics selected in processing 105 (processing 10
6) On the receiving side, the determination 203 becomes Yes, and the characteristics of the transmission / reception equalizer of the own device are set to the combination notified from the transmitting side (Process 204).

On the other hand, the transmitting side also sets the characteristics of its own transmission / reception equalizer to the combination selected in processing 105 (processing 1).
07).

In the present embodiment, the equalizer characteristic on the receiving side is notified to the transmitting side, and the optimum combination of the transmitting and receiving equalizer characteristics is selected on the transmitting side. And the receiving side may notify each other of the equalizer characteristics of the own device to the other side, and the transmitting side and the receiving side may select the combination of the own device in each judgment, or one of the transmitting side or the receiving side may first It selects the combination of the characteristics of its own transmission / reception equalizer and notifies the other party of the selection result, and the other party selects the combination of the characteristics of its own transmission / reception equalizer that matches the notified combination. You may.

By performing the processing up to the processing 107 on the transmitting side and the processing up to the processing 204 on the receiving side, it is possible to set the transmission / reception equalizer to a characteristic that can optimally compensate the line characteristic.

Further, after the process 204, the receiving side monitors whether or not the test signal from the transmitting side is received by the modem 9 (No at 205), and the transmitting side transmits the test signal by the modem 9 (No. 205). Process 108).

A test signal transmitted from the modem 9 on the transmitting side and received by the modem 9 on the receiving side includes a transmitting equalizer 31 on the transmitting side, a line path that actually connects the transmitting side and the receiving side, and Since the signal passes through the reception equalizer 32 on the reception side, the characteristics of the transmission equalizer 31 on the transmission side and
If the characteristics of the reception equalizer 32 on the reception side can sufficiently correct the distortion of the frequency characteristics and the phase characteristics that occurs in the line path actually connecting the transmission side and the reception side, the modem 9 on the transmission side can be used. The transmitted test signal should be received by the receiving modem 9 without distortion.

[0034] The receiving side, if the determination 205 is Yes,
The frequency characteristics and the like of the received test signal are measured (Step 20).
6) As a result, it is determined whether the correction by the transmission / reception equalizer is OK (NG) or not (decision 207).

If it is NG (N in decision 207)
o), a test result signal indicating NG is transmitted to the transmitting side (process 208), and the process returns to the determination 203.

On the other hand, after the process 108, the transmitting side monitors whether a test result signal is received from the receiving side (No loop in decision 109).
s) It is determined whether or not the received test result signal is a signal indicating OK (signal indicating NG) (decision 11)
0), if the signal is NG (No in decision 110), the process returns to step 105.

As a result, even if the distortion of the actual line path cannot be sufficiently corrected by the combination of the transmission and reception equalizers selected first, the combination of the transmission and reception equalizer characteristics shown in FIG. , Another optimal combination can be reselected by the processing 105, and reset by the processing 107 and the processing 204.

Further, even if the characteristics of the transmission / reception equalizer are reselected and reset, if the judgment 207 is No,
Reselection by processing 105, processing 107 and processing 204
Are repeated, and a transmission / reception equalizer is set in the most optimal combination as possible.

If the judgment is OK in judgment 207 (Yes in judgment 207), a test result signal indicating OK is transmitted to the transmitting side (step 209), and the process waits until reception starts (step 210 in step 210). No loop).

On the other hand, after the process 108, the transmitting side monitors whether a test result signal is received from the receiving side (No loop in decision 109).
s) It is determined whether or not the received test result signal is a signal indicating OK (signal indicating NG) (decision 11)
0), if the signal is OK (Yes in decision 110), communication is started (process 111), and in response to process 111, decision 210 is Yes in the receiving side, and thereafter, the transmitting side The receiving side and the receiving side transmit and receive a facsimile message (steps 112 and 211).

The transmission / reception processing in the processing 112 and the processing 211 can be normally performed in most cases because the transmission / reception equalizer characteristics are optimally selected and set prior to the start of communication. However, since the selection setting of the transmission / reception equalizer characteristics prior to the start of communication may be insufficient in actual communication, the reception side determines that the reception processing is normal (OK) after the reception processing of step 211 is completed. Whether there was (NG)
That is, it is determined whether or not the number of lines in which the transmission error has occurred is within an allowable range (decision 212).

If the receiving process is not normal (decision 2
No. 12), a communication result signal indicating NG is transmitted to the transmitting side (process 208), and the process returns to the determination 203.

On the other hand, the transmitting side monitors whether or not the communication result signal is received from the receiving side after the transmitting processing of processing 112 (No loop of decision 113).
3), it is determined whether or not the received communication result signal is a signal indicating OK (signal indicating NG) (decision 1)
14) If the signal is NG (decision 114)
No), the process returns to step 105.

With the transmission / reception equalizer characteristics selected and set prior to the start of the actual communication, even if the actual communication fails, the combination of the transmission / reception equalizer characteristics shown in FIG. , Another optimum combination is re-selected by the processing 105, and the processing 10
7 and the process 204, and
Even if the characteristics of the transmission / reception equalizer are reselected and reset, if the determination 212 is No, the reselection by the processing 105 and the resetting by the processing 107 and the processing 204 are repeated, and the optimum A transmission / reception equalizer is set by the combination.

If it is determined in the determination 212 that the reception processing is normal (Yes in the determination 212), a communication result signal indicating OK is transmitted to the transmitting side (processing 21).
3), end the process.

On the other hand, after the process 112, the transmitting side monitors whether a communication result signal is received from the receiving side (decision 1).
13 (No loop), upon reception (Ye in decision 113)
s) It is determined whether the received communication signal is a signal indicating OK (signal indicating NG) (decision 114), and OK
If it is a signal to the effect (Yes in decision 114),
The process ends.

In the embodiment described above, the present invention is applied to a facsimile apparatus which is a communication terminal apparatus for transmitting and receiving facsimile messages. However, the present invention is not limited to the contents of data to be transmitted and received. Instead, the present invention can be similarly applied to any communication terminal device provided with a transmission and reception equalizer that corrects distortion in a line path of a transmission / reception signal exchanged with a partner device via a line via a modem.

[0048]

According to the first aspect of the present invention, the own device and the other device do not independently set the characteristics of the transmission / reception equalizer, but use the information of the characteristics of the transmission / reception equalizer that can be set in advance by the own device. While notifying the other party, the other party recognizes the information of the transmission and reception equalizer characteristics that can be set by the other party, and recognizes the combination of the transmission and reception equalizer characteristics that can be set by the other party and its own device. To select and set the combination that provides the best correction characteristics, it is possible to improve the communication quality by optimally correcting the distortion of the transmission and reception signals on the line path between the own device and the other device. can get.

According to the second aspect of the present invention, after the characteristics of the transmission / reception equalizer are set by the characteristics setting means,
Since the effect of the correction by the transmission / reception equalizer on the line route actually connected between the own device and the partner device has been confirmed, distortion of the actually connected line route, change in the situation due to distance, etc., can be accurately performed. The effect that can respond is obtained.

According to the third aspect of the present invention, if the combination of the characteristics of the transmission / reception equalizer selected first cannot sufficiently correct the distortion or the like of the actually connected line path, the other combinations are not included. In order to re-select and re-set the optimal combination, it is possible to further optimally correct the distortion of the transmission / reception signal on the line path between the own device and the other device, thereby improving the communication quality. can get.

According to the fourth aspect of the present invention, if the combination of the characteristics of the transmission / reception equalizer selected first cannot sufficiently correct the distortion or the like of the actually connected line path, the other combinations will not be used. If the optimum combination is re-selected and re-set, and the re-set transmission / reception equalizer characteristic combination still cannot sufficiently correct the distortion and the like of the actually connected line path, further Since the most suitable combination is re-selected from among the combinations, it is possible to further optimally correct the distortion of the transmission / reception signal in the line path between the own device and the other device, thereby improving the communication quality. can get.

According to the fifth aspect of the present invention, in the combination of the characteristics of the transmission / reception equalizer selected before the start of communication, if the actual communication does not end normally, the optimum combination among the other combinations is selected. Re-select and re-set, and re-execute communication, so that even if the combination of characteristics of the transmission / reception equalizer selected before the start of communication is inappropriate for actual communication, communication should be completed normally. The effect that becomes possible is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a block configuration of a facsimile apparatus as a communication terminal apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a modem interface of the facsimile apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a connection state of a switch and a transmission equalizer characteristic;

FIG. 4 is a diagram illustrating a relationship between a connection state of a switch and a reception equalizer characteristic;

FIG. 5 is a diagram showing storage contents according to the present invention of a ROM of the facsimile apparatus according to the embodiment of the present invention;

FIG. 6 is a diagram illustrating a transmission-side and reception-side facsimile apparatus that mutually transmits and receives via a line.

FIG. 7 is a flowchart illustrating a transmission / reception process performed by the facsimile apparatus according to the embodiment of the present invention as a transmission side facsimile apparatus and a reception side facsimile apparatus via a line.

FIG. 8 is a flowchart together with FIG. 7 showing a transmission / reception processing procedure performed by a facsimile apparatus according to an embodiment of the present invention as a transmission side and a reception side facsimile apparatus via a line.

9 is a flowchart showing a transmission / reception process performed by the facsimile apparatus according to the embodiment of the present invention as a transmission side and a reception side facsimile apparatus via a line, together with FIG. 7 and FIG.

FIG. 10 is a diagram showing storage contents according to the present invention of the RAM of the facsimile apparatus according to the embodiment of the present invention;

FIG. 11 is a diagram showing combinations of transmission / reception equalizer characteristics.

[Explanation of symbols]

 1, 1a, 1b Facsimile machine 2 System control unit 3 ROM 4 RAM 5 Scanner 6 Plotter 7 Encoding / decoding unit 8 Operation display unit 9 Modem 10 Modem interface unit 11 Network control unit 12 System bus 20 Line 30 2-wire / 4-wire Conversion circuit 31 transmission equalizer 31a characteristic 0 transmission equalizer 31b characteristic 1 transmission equalizer 31c characteristic 2 transmission equalizer 32 reception equalizer 32a characteristic A reception equalizer 32b characteristic B reception equalizer 32c characteristic C reception equalizer SW1a, SW1b, SW2x, SW2x SW Receiver amplifier

Claims (5)

[Claims] 1. A transmission equalizer for transmitting and receiving a signal by a modem to and from a partner device via a line to perform communication while correcting a signal from the modem with predetermined characteristics and transmitting the corrected signal to the partner device. A communication terminal device having a reception equalizer that corrects a signal from the partner device with a predetermined characteristic and causes the modem to receive the signal; and a self-characteristic storage unit that previously stores information on an equalizer characteristic that can be set for the self-device. Prior to the start of communication with the other device, own device characteristic notifying means for notifying the other device of information on the equalizer characteristics of the own device stored in the own device characteristic storage device, and A counterpart characteristic recognizing means for recognizing information of an equalizer characteristic which can be set by the counterpart notified by the counterpart; and an equalizer settable by the counterpart recognized by the counterpart characteristic recognizing means. A characteristic selection unit that selects a combination that optimizes communication signal correction from among combinations of the equalizer characteristics and the equalizer characteristics that can be set in the own device stored in the own device characteristic storage unit, and the characteristic selection unit. A communication terminal device comprising: a characteristic setting unit that sets the transmission and reception equalizers to selected characteristics. 2. A test signal transmitting means for transmitting a test signal to the partner device by the modem after setting the characteristics of the transmission / reception equalizer by the characteristic setting device, and receiving the test signal from the partner device by the modem. 2. The communication terminal device according to claim 1, further comprising a setting checking unit for checking the effect of the correction by the equalizer. 3. As a result of the confirmation by the setting confirmation means, if the characteristics of the transmission / reception equalizer selected by the characteristic selection means are insufficiently corrected, the characteristics can be set in the partner equipment recognized by the partner equipment characteristic recognition means. Equalizer characteristics,
With other equalizer characteristics that can be set in the own device stored in the own device characteristic storage means,
3. The method according to claim 2, further comprising: a characteristic reselecting unit that selects a combination that optimizes communication signal correction; and a characteristic resetting unit that sets a transmission / reception equalizer to a characteristic selected by the characteristic reselecting unit. The communication terminal device according to claim 1. 4. As a result of confirmation by the setting confirmation means, if the characteristics of the characteristic selection means or the transmission / reception equalizer reselected by itself are insufficiently corrected, the counterpart equipment recognized by the counterpart characteristic recognition means recognizes A characteristic reselecting unit that selects a combination that optimizes communication signal correction from other combinations of a settable equalizer characteristic and an equalizer characteristic that can be set in the own device stored in the own device characteristic storage unit. Characteristic re-setting means for setting the transmission / reception equalizer to the characteristic selected by the characteristic re-selection means; and re-transmitting a test signal by the modem after resetting the transmission / reception equalizer characteristic by the characteristic re-setting means. Test signal retransmitting means for reconfirming the effect of correction by the transmission / reception equalizer on the setting confirmation means of the apparatus. The communication terminal device according to claim 2, wherein: 5. An equalizer characteristic that can be set in the partner device recognized by the partner device characteristic recognizing means when the communication started after setting the combination of the characteristics of the transmission / reception equalizer is not completed normally; A post-communication characteristic reselecting unit that selects a combination that optimizes the communication signal correction from other combinations with the equalizer characteristics that can be set in the own device stored in the characteristic storage unit and the characteristic reselecting unit. The communication characteristic re-setting means for setting the transmission / reception equalizer to the selected characteristic, and a communication re-executing means for performing communication again after setting by the characteristic setting means after communication. 1, 2,
The communication terminal device according to any one of items 3 and 4.