JP2004282408A - Communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide communication equipment in which a terminating circuit with a proper termination characteristic is set. <P>SOLUTION: The energy of a received signal for a probing period of a V.34 modem is detected to determine the unmatching of a termination condition. This prevents characteristic deterioration caused by the unmatching of termination and improves a communication characteristic. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication device that uses an analog public network as a communication path.
[0002]
[Prior art]
For example, in Europe recently, telecommunications licensing in analog public networks, which previously differed from country to country, has been consolidated. However, it is considered that some exchangers and environments have conventionally been approved.
[0003]
In the case where an exchange or the like conforming to a plurality of authorizations exists, what is most affected is the termination characteristic of the connected terminal. In particular, ITU-T Recommendation V.1 requires high-speed modem communication. In a facsimile apparatus using a 34 modem, unless an appropriate terminating circuit is set, a situation such as frequent data errors occurs, and high-speed communication cannot be performed.
[0004]
Therefore, for example, the impedance of the termination circuit is set by measuring the signal level of the wraparound signal during signal transmission and calculating the signal level difference.
[0005]
[Patent Document 1]
JP-A-2002-190930
[Problems to be solved by the invention]
However, in such a conventional device, it is difficult to grasp the frequency characteristics, and a situation occurs in which an appropriate termination circuit cannot be set.
[0007]
The present invention has been made in view of such circumstances, and has as its object to provide a communication device that can set a termination circuit having appropriate termination characteristics.
[0008]
[Means for Solving the Problems]
According to the present invention, in a communication apparatus using an analog public network as a communication path, a network control apparatus having a plurality of termination circuits having different termination characteristics, a modem means for data communication, and the modem means perform before communication starts. An energy detecting means for detecting the energy of the received signal during the probing period is provided.Based on the detection result of the energy detecting means, the matching of the termination circuit used in the network control device is determined, and based on the determination result, The communication operation is performed after the termination circuit used is switched.
[0009]
Further, in a communication apparatus using an analog public network as a communication path, a network control apparatus having a plurality of termination circuits having different termination characteristics, a modem means for data communication, and a probing period performed by the modem means before starting communication. Comprising energy detection means for detecting the energy of the received signal in, based on the detection result of the energy detection means, to determine the matching of the termination circuit used in the network control device, based on the determination result, When the retransmission operation is performed in the data communication procedure, the termination circuit to be used is switched.
[0010]
Further, in a communication apparatus using an analog public network as a communication path, a network control apparatus having a plurality of termination circuits having different termination characteristics, a modem means for data communication, and a probing period performed by the modem means before starting communication. Comprising energy detection means for detecting the energy of the received signal in, based on the detection result of the energy detection means, to determine the matching of the termination circuit used in the network control device, based on the determination result, After switching the terminating circuit to be used, a communication operation is performed, and thereafter, the terminating circuit to be used is held.
[0011]
Further, in a communication apparatus using an analog public network as a communication path, a network control apparatus having a plurality of termination circuits having different termination characteristics, a modem means for data communication, and a probing period performed by the modem means before starting communication. And a terminating characteristic switching mask condition storing means for storing a switching mask condition for terminating characteristics of the terminating circuit, wherein the network control is performed based on a detection result of the energy detecting means. The matching of the termination circuit used in the device is determined, and only when the mask condition stored in the termination characteristic switching mask condition storage means is not satisfied, the termination circuit to be used is determined based on the determination result. After the switching, the communication operation is performed.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
FIG. 1 shows a group 3 facsimile apparatus according to one embodiment of the present invention.
[0014]
In FIG. 1, a system control unit 1 performs control processing of each unit of the group 3 facsimile apparatus, and a system memory 2 executes a control processing program executed by the system control unit 1 and a processing program. It stores various data and the like that are sometimes needed, and also constitutes a work area of the system control unit 1. The parameter memory 3 stores various information unique to the group 3 facsimile apparatus. The clock circuit 4 is for outputting current time information.
[0015]
The scanner 5 is for reading a document image at a predetermined resolution, the plotter 6 is for recording and outputting an image at a predetermined resolution, and the operation display unit 7 is for operating this group 3 facsimile apparatus. And consists of various operation keys and various indicators.
[0016]
The encoding / decoding unit 8 encodes and compresses the image signal and decodes the encoded and compressed image information into the original image signal. The image storage device 9 encodes and compresses the image signal. This is for storing a large number of image information in the closed state.
[0017]
The communication control unit 10 determines the termination characteristics of the connected exchanges, performs a predetermined group 3 facsimile transmission procedure, and implements communication control for exchanging image information with a partner terminal. The group 3 facsimile modem 11 is for realizing a group 3 facsimile modem function, and exchanges transmission procedure signals (a low-speed modem function (V.21 modem)) and mainly exchanges image information. (V.17 modem, V.34 modem, V.29 modem, V.27ter modem, etc.).
[0018]
The network control device 12 is for connecting the group 3 facsimile apparatus to the analog public network PSTN, has an automatic transmission / reception function, has a plurality of termination circuits having different characteristics, and has a plurality of termination circuits. One of them is selected and applied. The selection control of the termination circuit is performed by the communication control unit 10.
[0019]
The energy detection unit 13 detects that the group 3 facsimile modem 11 When the 34 modem function is realized, the energy of the received signal during the probing period is detected, and the detection result is output to the communication control unit 10.
[0020]
These system control unit 1, system memory 2, parameter memory 3, clock circuit 4, scanner 5, plotter 6, operation display unit 7, encoding / decoding unit 8, image storage device 9, and communication control unit 10 , Are connected to an internal bus 14, and data exchange between these elements is mainly performed through the internal bus 14.
[0021]
Further, data exchange between the communication control unit 10 and the group 3 facsimile modem 11, the network control device 12, and the energy detection unit 13 is directly performed.
[0022]
Here, as shown in FIG. 2, the communication control unit 10 includes termination switching mode information (always / at the time of retransmission) for designating whether the switching operation of the termination characteristic is always performed or only during the retransmission operation. In addition, termination switching mask condition information in which a country code for designating a country in which the switching operation of the termination characteristic is not performed is stored. Usually, a country code of a country that does not satisfy the approval is set by switching the termination condition. Note that significant information may not be registered in the termination switching mask condition information.
[0023]
Further, the communication control unit 10 holds the currently determined termination characteristic, and sets a termination circuit to be used in the network control device 12 according to the retained termination characteristic at the start of communication. ing.
[0024]
FIGS. 3A and 3B show an example of a plurality of termination circuits provided in the network control device 12. FIG. FIG. 1A shows a termination circuit A including one resistor R0, and FIG. 1B shows a composite circuit in which a parallel circuit of a resistor R2 and a capacitor C1 is connected in series to a resistor R1. FIG.
[0025]
The impedance characteristics of the terminating circuits A and B are as shown in FIG. Note that the circuit constants of the resistors R1 and R2 and the capacitor C1 of the termination circuit B need to be set to values according to the destination country.
[0026]
With the above configuration, the group 3 facsimile modem 11 has the When performing communication using the 34 function, the communication control unit 10 performs a process as shown in FIG. 4 to switch the termination circuit of the network control device 12.
[0027]
First, when a call arrives (process 101), energy at each frequency during the probing period of the group 3 facsimile modem 11 is input from the energy detector 13 (process 102), and the termination circuit at that time matches the termination characteristic of the analog public network. It is checked whether the process has been performed (process 103, judgment 104).
[0028]
When it is determined that there is a mismatch, if the result of determination 104 is YES, it is checked whether or not information is registered in the termination switching mask condition information (determination 105). If the result of determination 105 is YES, The country code registered in the terminal at the time of installation is checked to determine whether the mask condition is satisfied (decision 106).
[0029]
When the result of the determination 106 is NO, the terminal switching mode information is checked to determine whether or not it is set only for retransmission (decision 107). When the result of the determination 107 is NO, the termination of the network control device 12 is determined. The circuit is switched (process 108).
[0030]
Next, data reception is started (step 109), and the process waits until reception is completed (NO loop of determination 110). Then, the receiving operation ends, and if the result of the determination 110 becomes YES, the termination condition at that time is held (process 111), and the operation at this time ends.
[0031]
When the result of the judgment 107 is YES, when the result of the judgment 106 is YES, and when the result of the judgment 104 is NO, the data reception is started with the setting contents of the first termination condition (processing 112). ), It is monitored whether or not a retransmission operation is performed until the reception is completed (NO loop of determinations 113 and 115).
[0032]
If a retransmission operation has occurred and the result of determination 113 is YES, the terminal circuit of network control device 12 is switched (process 114), and the flow proceeds to determination 115. When the receiving operation is completed and the result of determination 115 is YES, the operation at this time is ended.
[0033]
Thus, in the present embodiment, the V.V. Since the termination condition mismatch is determined by detecting the energy of the received signal during the probing period of the 34 modem, the characteristic degradation due to the termination mismatch can be prevented, and the communication characteristics can be improved. Further, since the termination circuit can be switched only at the time of retransmission, side effects due to the termination circuit switching can be avoided as much as possible. In addition, since the termination condition is maintained, deterioration of all transmission / reception characteristics can be prevented, and communication characteristics can be improved. Further, since the termination switching mask condition can be set, it is possible to prevent the terminal from being inadvertently switched and not conforming to the approval.
[0034]
In the above-described embodiment, the number of terminating circuits provided in the network control device is two. However, three or more terminating circuits may be provided.
[0035]
In the above-described embodiment, the V.V. Although the case where the present invention is applied to a group 3 facsimile apparatus having a 34 modem function has been described, the present invention can be similarly applied to other communication apparatuses.
[0036]
【The invention's effect】
As described above, according to the present invention, the V.V. Since the termination condition mismatch is determined by detecting the energy of the received signal during the probing period of the 34 modem, the characteristic degradation due to the termination mismatch can be prevented and the communication characteristics can be improved. In addition, since the termination circuit can be switched only at the time of retransmission, the effect that the side effect due to the termination circuit switching can be avoided as much as possible can be obtained. In addition, since the termination condition is maintained, all transmission / reception characteristics can be prevented from deteriorating and communication characteristics can be improved. In addition, since the termination switching mask condition can be set, there is also obtained an advantage that the terminal is not switched carelessly and thus does not become incompatible with the approval.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a group 3 facsimile apparatus according to one embodiment of the present invention.
FIG. 2 is a schematic diagram showing an example of termination switching mode information and termination switching mask condition information.
FIG. 3 is a block diagram showing an example of a plurality of termination circuits provided in the network control device 12, and a graph showing an example of their impedance characteristics.
FIG. 4 shows a group 3 facsimile modem 11 having a 34 is a flowchart illustrating an example of termination circuit switching processing performed by the communication control unit 10 when performing communication using the 34 function.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Communication control part 11 Group 3 facsimile modem 12 Network control device 13 Energy detection part

Claims (4)

In a communication device using an analog public network as a communication path,
A network control device having a plurality of termination circuits having different termination characteristics,
Modem means for data communication;
The modem means comprises energy detection means for detecting the energy of the received signal during the probing period performed before the start of communication,
Based on the detection result of the energy detecting means, the matching of the termination circuit used in the network control device is determined, and based on the determination result, the termination operation to be used is switched, and then the communication operation is performed. A communication device characterized by the above-mentioned. In a communication device using an analog public network as a communication path,
A network control device having a plurality of termination circuits having different termination characteristics,
Modem means for data communication;
The modem means comprises energy detection means for detecting the energy of the received signal during the probing period performed before the start of communication,
Based on the detection result of the energy detection means, the matching of the terminating circuit used in the network control device is determined, and based on the determination result, when the retransmission operation in the data communication procedure is performed, A communication device for switching the termination circuit. In a communication device using an analog public network as a communication path,
A network control device having a plurality of termination circuits having different termination characteristics,
Modem means for data communication;
The modem means comprises energy detection means for detecting the energy of the received signal during the probing period performed before the start of communication,
Based on the detection result of the energy detecting means, the matching of the terminating circuit used in the network control device is determined, and based on the result of the determination, the terminal circuit to be used is switched, and then the communication operation is performed. And a communication device for holding the termination circuit to be used thereafter. In a communication device using an analog public network as a communication path,
A network control device having a plurality of termination circuits having different termination characteristics,
Modem means for data communication;
Energy detection means for detecting the energy of the received signal during the probing period performed by the modem means before the start of communication,
A terminating characteristic switching mask condition storing means for storing a terminating characteristic switching mask condition of the terminating circuit;
Based on the detection result of the energy detection means, the matching of the termination circuit used in the network control device is determined, and only when the mask condition stored in the termination characteristic switching mask condition storage means is not satisfied. A communication device for performing a communication operation after switching the terminating circuit to be used based on a result of the determination.

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