JP2002009867A - Signal transmission method and communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal transmission method for locally transmitting different signals without affecting a transmission signal and a reception signal, which are transmitted and received by two of twisted pair wires with simple constitution without the need of additional wiring and a modulation/ demodulation circuit. SOLUTION: Signals S3 are added to the transmission twisted pair wires 2T and the reception twisted pair wires 2R at common modes. Thus, the signals are transmitted between the two of the twisted pair wires.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a key telephone system and an ISDN (Integrated Service).
ices Digital Network) S / T
In extension transmission using two pairs of pairs at a point, it is suitable for transmitting and receiving signals locally between a plurality of terminals without affecting transmission and reception signals transmitted on each pair. The present invention relates to a signal transmission method and a communication device.

[0002]

2. Description of the Related Art For example, like the S / T point of ISDN,
DSU (Digital Service Unit;
Line terminating equipment) and a plurality of ISDN terminals connected in a multipoint manner, a transmission circuit for transmitting a signal to a transmission pair, and a reception circuit for reception to a reception pair. Connected to send and receive signals.

Also, between the main unit of the key telephone system and the extension telephone, a transmission signal is transmitted and received via a transmission pair line, and a reception signal is transmitted and received via a reception pair line. Is going.

[0004] In signal transmission using such a paired line, noise in the common mode is canceled by the paired line, so that signal transmission hardly affected by noise can be performed.

By the way, recently, as an ISDN terminal,
In many cases, personal computers are connected via terminal adapters. Therefore, there is an increasing demand for transmitting and receiving signals locally between a plurality of ISDN terminals connected in a multipoint manner.

In this case, a signal can be transmitted and received locally between a plurality of ISDN terminals connected in a multipoint manner without affecting a transmission signal and a reception signal transmitted on each pair line. As a method, a method of adding a new medium such as a third pair line, a method of allocating a high frequency band to the locally transmitted / received signal, and transmitting the signal by a frequency division method, for example, are known.

[0007]

However, in the above-mentioned method, a new pair wire or the like must be additionally wired, so that a change for transmitting and receiving signals locally becomes large-scale, and the cost increases. There is a problem that also becomes large.

On the other hand, according to the method (1), it is not necessary to add a pair line, but the signal frequency band transmitted and received locally is the frequency band of the transmission signal and the reception signal transmitted and received by two pairs of pair lines. In the case where the signal is close to the signal, it is difficult to separate the signal by the filter. Therefore, the signal to be transmitted and received locally needs to be modulated and demodulated to a high frequency band and transmitted. For this reason, the modulation / demodulation circuit must be provided separately, and there is also a problem that the cost burden is heavy.

In view of the above, the present invention does not require additional wiring or a modulation / demodulation circuit, has a simple configuration, and does not affect transmission signals and reception signals transmitted and received on two pairs of pairs. An object of the present invention is to provide a signal transmission method capable of transmitting a signal and a communication device used in the method.

[0010]

In order to solve the above-mentioned problems, a signal transmission method according to the present invention uses a communication transmission line using two pairs of a transmission pair and a reception pair.
In the signal transmission method for transmitting and receiving signals, the two pairs of paired lines are added between the paired line for transmission and the paired line for reception by applying a signal in phase to each of the paired lines. It is characterized in that a signal is transmitted between them.

A communication device according to the present invention is a communication device connected to a communication transmission line using two pairs of a transmission line and a reception pair. And a pair transmission line transmission circuit for transmitting a signal so as to add a signal in the same phase to each pair line between the pair line for reception and the pair line for reception.

Further, a communication device according to the present invention is a communication device connected to a communication transmission line using two pairs of a transmission pair line and a reception pair line, and And an inter-pair transmission signal receiving circuit for receiving a signal applied in-phase to each of the paired wires between the paired wires and the pair of reception wires.

[0013]

In the signal transmission method according to the present invention having the above-described structure, a signal is added in phase to the transmission pair line and the reception pair line, so that the transmission pair line and the reception pair line are added. The paired line is a paired signal line, and a signal is transmitted.

In a transmission line using a pair of wires, a signal in the common mode is canceled between the pair of wires, so that a signal transmitted through the transmission line of the pair of wires is not affected. . Therefore, the signal transmitted between the two pairs of wires is added to each of the pair of wires for transmission and the pair of wires for reception in phase, so that the signals are canceled and do not affect the transmission signal and the reception signal.

In the case where two pairs of transmission lines are considered as a pair, the transmission signal is canceled from the transmission pair to obtain only the transmission signal between the pairs. The received signal is canceled from the receiving pair line, and only the inter-pair transmission signal (in phase opposite to the transmitting pair side) is obtained. Therefore, transmission of a transmission signal between pairs is realized.

Further, in the communication device having the above-described configuration, between the transmission pair and the reception pair, transmission between pairs is performed so that signals are applied to each pair in the same phase. Just by including the signal transmission circuit, another signal can be transmitted without affecting the transmission signal and the reception signal.

[0017] Further, only by providing an inter-pair transmission signal receiving circuit for receiving a signal applied in-phase to each pair between the pair of transmission and the pair of reception, the transmission is performed. Another signal can be received without affecting the signal and the received signal.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a signal transmission method and a communication device according to the present invention when applied to a key telephone system will be described with reference to the drawings.

FIG. 2 is a block diagram showing an outline of the key telephone system in this embodiment. In FIG. 2, reference numeral 10 denotes a main unit which is connected to a telephone line 1 connected to a public telephone network and to an internal line 2.
A plurality of extension telephones 20 are connected to the inner line 2, and in this embodiment, a communication adapter 30 for transmitting and receiving a transmission signal between pairs, which will be described later, is connected.

In this embodiment, a terminal for transmitting and receiving a signal as an inter-pair transmission signal can be connected to each of the extension telephones 20. In the example shown in FIG. A personal computer 40 is connected to the extension telephone set 20. Communication adapter 3
Similarly, a terminal that transmits and receives a signal as an inter-pair transmission signal is connected to each of the terminals 0, and a personal computer 40 is connected as an example of this terminal in the example of FIG.

As shown in FIG. 1, the inner line 2 is composed of a reception pair line 2R composed of a pair of signal lines 2Ra and 2Rb and a transmission pair line 2T composed of a pair of signal lines 2Ta and 2Tb. It consists of a pair of pairs. In the description of this specification, a transmission signal transmitted between a pair 2R and a transmission line 2T is transmitted separately from a reception signal transmitted through a reception pair 2R and a transmission signal transmitted through a transmission pair 2T. The signal to be transmitted is called an inter-pair transmission signal.

The receiving pair line 2R of the inner line 2 is connected to the main unit 1
0, which is connected to both ends of a secondary winding of a first signal transmission transformer (hereinafter, simply referred to as a transformer) 101 for a reception signal, and a first signal for a reception signal of the extension telephone 20. Both ends of the secondary winding of the transformer 201 and both ends of the secondary winding of the first transformer 301 of the communication adapter 30 are connected.

The transmission pair 2T of the inner line 2 is connected to the main unit 1
0 is connected to both ends of the secondary winding of the second transformer 102 for the transmission signal of the extension telephone 20 and both ends of the secondary winding of the second transformer 202 for the transmission signal of the extension telephone 20 and the second end of the communication adapter 30. The second transformer 302 is connected to both ends of the secondary winding.

In the main unit 10, the center tap of the secondary winding of the first transformer 101 and the second transformer 10
And the center tap of the secondary winding of the third transformer 103
Are connected to both ends of the secondary winding. This third transformer 1
Reference numeral 03 denotes a transmission / reception of a transmission signal between pairs in the main device 10. One end and the other end of the secondary winding of the third transformer 103 are respectively connected to the secondary winding of the first transformer 101. This third transformer 1 is connected to a point tap and a center point tap of the secondary winding of the second transformer 102.
03, the transmission signals between pairs transmitted to the transmission pairs 2T and 2R are the signal lines 2Ta and 2T of the pair 2T.
b and in-phase to the signal lines 2Ra and 2Rb of the pair line 2R. Further, the transmission signal between the pair wires added in phase to each of the pair wires 2T and 2R is:
It is extracted by the third transformer 103.

Similarly, in the extension telephone set 20, the midpoint tap of the secondary winding of the first transformer 201 and the midpoint tap of the secondary winding of the second transformer 202 correspond to the transmission signal of the pair-to-line transmission signal. The communication adapter 30 is connected to both ends of the secondary winding of the third transformer 203 for transmission and reception. In the communication adapter 30, the center tap of the secondary winding of the first transformer 301 and the secondary winding of the second transformer 302 are connected. Is the third tap for transmitting and receiving transmission signals between pairs.
Are connected to both ends of the secondary winding of the transformer 303.

With the above configuration, the transmission signal between the pair transmitted to the transmission pairs 2T and 2R through the third transformer 203 of the extension telephone set 20 or the third transmission signal of the communication adapter 30 is transmitted. The inter-pair transmission signal transmitted to the pair wires 2T and 2R for transmission through the transformer 303 is added to the signal lines 2Ta and 2Tb of the pair line 2T in the same phase, and the signal lines 2Ra and 2R of the pair line 2R.
b in phase. Further, the transmission signal between the pair lines added to each of the pair lines 2T and 2R in the same phase is transmitted by the third transformer 203 in the extension telephone set 20 to the communication adapter 30.
In the third transformer 303, each is extracted.

The pair line 2R and the pair line 2T are terminated by terminating resistors 3R and 3T, respectively.

Next, the internal configuration of the main unit 10, the extension telephone 20, and the communication adapter 30 will be further described.

In the present embodiment, the main unit 10 is provided as shown in FIG.
The control unit 109 is connected to the system bus 110, and the line interface 104, the exchange switch 105, the extension interface 106, the router unit 114, and the setting storage unit 117 Are connected.

The power supply circuit 111 of the main unit 10 is connected to a commercial power supply via an AC adapter (not shown). The power supply circuit 111 is connected to the main unit 1 from a commercial power supply.
A power supply voltage for the first and second transformers 101 and 102 is connected to one end and the other end of the power supply circuit 111 via choke coils 112 and 113, respectively. The power supply voltage from the power supply circuit 111 is connected to the center tap of the secondary winding.
It is supplied as a power supply voltage for the extension telephone 20 and the communication adapter 30.

The line interface 104 is connected to the main unit 1
0 is connected to the telephone line 1 and controlled. The exchange switch 105 controls the line interface 104 and the extension interface 106 under the control of the control unit 109.
, And the flow of signal transmission and reception between the line interface 104 and the router unit 114 are controlled.

The extension interface 106 is connected to the exchange switch 105, sends out a transmission signal from the exchange switch 105 to the first transformer 101 through the amplifier 107, and sends a signal sent through the second transformer 102. The signal is received via the amplifier 108 and transmitted to the telephone line 1 through the exchange switch 105 and the line interface 104. Also, this extension interface 1
Reference numeral 06 controls an extension call under the control of the control unit 109, thereby enabling an extension call between a plurality of extension telephones 20.

The router section 114 sends data from the personal computer 40 to the telephone line 1 or sends data sent through the telephone line 1 to the personal computer 40. The setting data of the router unit 114 is stored in the setting storage unit 117.
Is stored in The setting storage unit 117 also stores setting data for a plurality of extension telephones 20 and other setting data.

The exchange of signals between the router 114 and the extension side of the main unit 10 is exchanged as a transmission signal between pairs, and the exchange between the one end of the primary winding of the third transformer 103 and the router 114 is performed. A transmission amplifier 115 and a reception amplifier 116 for transmitting transmission signals between pairs are provided between them.

Therefore, the first and second transformers 1
01, 102 connected to the center tap of the secondary winding
The transformer 103, the amplifiers 115 and 116, and the router unit 114 constitute a transmission / reception unit for transmission signals between pairs of the main apparatus.

Next, an example of the internal configuration of the extension telephone 20 will be described. FIG. 4 is a block diagram showing the configuration of the extension telephone 20 used in this embodiment.

As shown in FIG. 4, a received signal (received voice signal) obtained from the first transformer 201 connected to the receiving pair line 2R is supplied to the telephone circuit 206 through the amplifier 204. Then, the audio signal is supplied from the telephone circuit unit 206 to the speaker of the handset 207 and reproduced. The voice signal (transmitted voice signal) collected by the microphone of the handset 207 is transmitted to the telephone circuit unit 2.
06. Then, the signal is transmitted from the telephone circuit unit 206 to the second transformer 202 connected to the transmission pair 2T via the amplifier 205. With the above configuration, the extension telephone 20 can make an external call through the telephone line 1 and also can make an extension call with another extension telephone 20.

The power supply voltage of the extension telephone 20 is DC /
Obtained from DC converter 208. In the DC / DC converter 208, as described above, the power supply voltage from the main device 10 is extracted through the choke coils 209 and 210 as the voltage between the center taps of the first and second transformers, and the power supply voltage From the power supply voltage for the extension telephone.

The extension telephone 20 further includes a pair-to-line transmission signal control unit 211. The line-to-line transmission signal control unit 211 includes first and second transformers 201 and 202.
Transformer 2 connected to the center tap of the secondary winding of
03 and the amplifiers 212 and 213, between the receiving pair line 2R and the transmitting pair line 2T, transmission is performed in such a manner that an in-phase transmission signal is added to each pair line in phase. A transmission signal transmission / reception means for receiving a transmission signal between pairs applied in-phase to each pair between the transmission line 2R and the transmission pair 2T.

In this embodiment, the line-to-line transmission signal control unit 211 is provided with an interface for connecting a transmission / reception terminal of the line-to-line transmission signal to the extension telephone set 20, although not shown. In this example, the personal computer 40 is connected via the interface of the transmission signal control unit 211 as a transmission / reception terminal for transmission signals between transmission lines. Then, the line-to-line transmission signal control unit 211 supplies the transmission data received from the personal computer 40 to the third transformer 203 through the amplifier 212 and receives the reception data obtained by the third transformer 203 through the amplifier 213. And a function of transferring the data to the personal computer 40.

Next, an example of the internal configuration of the communication adapter 30 will be described. FIG. 5 is a block diagram showing a configuration of the communication adapter 30 used in this embodiment. This communication adapter 30 can be used without using the extension telephone 20.
It is used when two pairs of wires 2R and 2T are used as a transmission path of a transmission signal between pairs to perform communication.

As shown in FIG. 5, the configuration of the communication adapter 30 is the same as the configuration of the extension telephone 20 except for the amplifiers 204 and 205, the telephone circuit unit 206 and the handset 207, and includes the DC / DC converter 304 and the choke coil 30.
5, 306, an inter-pair transmission signal control unit 307, and amplifiers 308 and 309.

The communication adapter 30 is connected to the extension telephone 20
, Except for the amplifiers 204 and 205, the telephone circuit unit 206, and the handset 207, it is less expensive than the extension telephone 20, and the transmission / reception terminal for transmission signals between pairs, in this example, the personal computer 40 is For the purpose of connecting to two pairs of pairs 2R and 2T as transmission lines for line-to-line transmission signals, the use of the communication adapter 30 allows a system to be constructed at low cost.

Next, the operation of the key telephone system configured as described above when transmitting an inter-pair transmission signal will be described in more detail. The following description of the operation will be made as follows. When the extension telephone 20 is making an outside call via the main device 10, the data as a pair-to-pair transmission signal is transmitted between the two personal computers 40 via the communication adapters 30, respectively. Is transmitted and received.

FIG. 6 is a diagram for explaining the operation of the key telephone system in that case. FIG. 7 is a diagram showing transmission signal waveforms in the respective main parts.

As shown in FIG. 6, the main apparatus 10 sends the other party's call voice information (received voice information) S1 transmitted through the telephone line 1 to the extension telephone 20 through the receiving pair line 2R. The transmission voice information S2 from the extension telephone 20 is transmitted to the main unit 10 via the transmission pair 2T.
The main apparatus 10 sends the transmission voice to the other party through the telephone line 1.

The key telephone system according to the present embodiment
It is configured as a digital system and has a paired line 2R for reception.
And call voice information S1, transmitted over the transmission pair 2T.
S2 is a PCM signal.

In FIG. 6, when the extension telephone 20 is making an outside call via the main unit 10, the two personal computers 40 are connected via the communication adapter 30, respectively. This is a case where data S3 as a transmission signal is transmitted and received.

In the case of this embodiment, the plurality of personal computers 40 are CSMA / CD (Carrier).
r Sense Multiple Access w
the data S3 as a transmission signal between pairs on a single transmission line composed of two pairs of pairs 2R and 2T while avoiding collision of data transmission by a carrier detection multiple access / collision detection) system. Send and receive. In this case, the frequency band of the data S3 may overlap with the frequency bands of the information S1 and S2, but better transmission quality is obtained without overlapping.

Now, for example, the received voice information S1 transmitted on the receiving pair 2R is as shown in FIG. 7A, and the transmitted voice information S1 transmitted on the transmitting pair 2T is shown in FIG. S
2 is as shown in FIG. 7B. In this call state, one of the personal computers 40 in FIG.
It is assumed that the data S3 as shown in FIG. 7C is supplied to the inter-pair transmission signal control unit 307 as an inter-pair transmission signal from the other personal computer 40 in FIG.

Then, the data S 3 is transmitted from the line-to-line transmission signal control unit 307 through the amplifier 308 to the third transformer 3.
03 is supplied to the primary winding. At this time, the data S3 appearing in the secondary winding of the third transformer 303 passes through the middle point multi-tap of the secondary winding of the first transformer 301 to the signal lines 2Ra and 2Rb of the receiving pair line 2R in the same phase. In addition, the signal lines 2Ta and 2T of the transmission pair line 2T are transmitted through the midpoint tap of the secondary winding of the second transformer 302.
b in phase.

Therefore, a signal S4a (see FIG. 7D) obtained by adding the data S3 to the received voice information S1 is transmitted on one signal line 2Ra of the paired reception line 2R. On the other signal line 2Rb of the paired line 2R, the reception voice information S1 is inverted to the polarity of the data S3.
Is added to the transmission of the signal S4b (see FIG. 7E).

However, in the first transformer 201 of the extension telephone set 20, the signal S4b is subtracted from the signal S4a, so that the data S3 is canceled (FIG. 7F ) Signal S4c
(= S1)), the first transformer 2 of the extension telephone 20.
01, only the received voice information S1 is obtained, and the received voice information S1 is transmitted through the amplifier 204 to the telephone circuit 20.
6. In the telephone circuit section 20, the received voice information S1 is converted into an analog received voice signal,
And sound is reproduced by the speaker of the handset 207.

As described above, since the data S3 (in the opposite phase to the data S3 to the receiving pair 2R) is added to the transmitting pair 2T in the same phase, one of the transmitting pair 2T is added. The signal line 2Ta transmits a signal S5a (see FIG. 7 (G)) obtained by adding the data S3 to the transmission voice information S2, and the other signal line 2Tb of the transmission pair line 2T.
Then, the transmission voice information S2 is replaced with the data S
The signal S5b (see FIG. 7 (H)) to which the signal S3b (the phase opposite to the data S3 to the receiving pair line 2R) is added is transmitted.

However, in the second transformer 102 of the main unit 10 of the extension telephone 20, the signal S5b is subtracted from the signal S5a, so that the data S3 is canceled like the superimposed noise in the in-phase mode ( 7 (I) (see signal S5c (= S2)), only the transmission voice information S2 is obtained from the second transformer 201 of the main device 10, and the transmission voice information S2 is transmitted through the amplifier 108 and the circuit interface 104. Sent to telephone line 1.

At the midpoint tap of the first transformer 301 of the communication adapter 30 connected to the receiving pair line 2R, the signal obtained by adding the signal S4a of the signal line 2Ra and the signal S4b of the signal line 2Rb in phase. (S4a + S4b), and the received voice information S1 is canceled, leaving only the data S3. At the middle tap of the second transformer 302 of the communication adapter 30 connected to the transmission pair 2T, the signal S5a of the signal line 2Ta and the signal S5b of the signal line 2Tb are connected.
Becomes a signal (S5a + S5b) added in phase, so that the transmission voice information S2 is canceled and the data S3
(A phase opposite to the data S3 of the first transformer 201) is obtained.

Therefore, the signal S6 = (S4a + S4b) -from the third transformer 303 of the communication adapter 30.
(S5a + S5b) = S3 (see FIG. 7 (J)) is obtained. That is, only the data S3 is obtained from the third transformer 303 of the communication adapter 30 on the receiving side, and is supplied to the transmission signal control unit 307 via the amplifier 309, and transmitted from the transmission signal control unit 307. The data is transferred to the personal computer 40.

As described above, in the key telephone system according to the present embodiment, even during a call, the two pairs of wires 2 are not affected by noise or the like on the call voice.
By using the transmission path between R and 2T, transmission of other data such as computer data as in the above example becomes possible. Therefore, it is not necessary to add a pair of transmission lines for transmitting the other data, and it is also necessary to add a circuit such as a filter to separate the call voice information from the another data. Absent.

Further, since data is transmitted using the transmission line between the two pairs of wires 2R and 2T, the data is also
It is not affected by common mode noise,
The transmission path is less susceptible to external noise.

In the above-described example, the case where computer data is transmitted and received during an external call has been described. However, even when an internal call is being performed, computer data can be transmitted and received in a similar manner.

In the above description, the transmission of the transmission signal between pairs is performed in the case of data transmission between the personal computers 40 connected to the communication adapter 30.
Data transmission between the personal computers 40 connected to the extension telephone set 20, and the personal computer 40 connected to the communication adapter 30 and the personal computer 40 connected to the extension telephone set 20.
Data transmission between the personal computer 40 connected to the communication adapter 30 or the personal computer 40 connected to the extension telephone 20 and the main device 10 Transmission can be performed in the same manner as described above.

Main device 10 and personal computer 4
0 to the main unit 10
The setting information for the router unit 114 can be set in the main device 10 using the personal computer 40 and stored in the setting storage unit 117. Also, the data from the personal computer 40 is sent to the main device 10 as a transmission signal between pairs, and the
, The data can be sent to the telephone line 1 through the exchange switch 105 and the line interface 104, and the data from the telephone line 1 is received by the personal computer 40 as a pair-to-line transmission signal through the router unit 114. be able to.

In the above-described embodiment, the key telephone system is used.
In the extension transmission line using two pairs of pairs at the S / T point of the DN, in the same manner as described above, the above-mentioned inter-pair transmission signal is superimposed and transmitted between the two pairs of pairs. be able to. Further, the present invention is applicable to all communication systems using two pairs of wires for transmission and reception, respectively.

In the above-described embodiment, transmission and reception of transmission signals between pairs are performed between personal computers connected to extension telephones and communication adapters. A terminal device such as an extension telephone that transmits and receives a transmission signal and a reception signal through each of them may have a function of generating and transmitting an inter-pair transmission signal and receiving and performing predetermined processing. Needless to say.

[0065]

As described above, according to the present invention, another signal can be transmitted between two pairs of pairs without affecting the signal transmitted on each of the two pairs of pairs. Can be transmitted as And according to this invention,
There is no need to additionally provide another paired wire in addition to the existing two pairs, and there is no need for a modulation / demodulation circuit or the like, a separation filter, or the like.

Further, since the transmission signal between the pair is transmitted using the transmission line between the two pairs, the transmission signal between the pair is not affected by the common mode noise, and the external noise is not affected. Transmission lines that are not easily affected by

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a connection mode between two pairs of wires and each device in a key telephone system to which an embodiment of a signal transmission method according to the present invention is applied.

FIG. 2 is a diagram showing an overall outline of a key telephone system to which an embodiment of a signal transmission method according to the present invention is applied.

FIG. 3 shows a main device 10 in the system shown in FIGS. 1 and 2;
FIG. 3 is a block diagram illustrating a configuration example of FIG.

FIG. 4 is a block diagram showing a configuration example of an extension telephone 20 in the systems of FIGS. 1 and 2;

FIG. 5 is a block diagram showing a configuration example of a communication adapter 30 in the systems of FIGS. 1 and 2;

FIG. 6 is a diagram showing an example of a mode of signal transmission in the systems of FIGS. 1 and 2;

FIG. 7 is a diagram illustrating an example of a transmission signal waveform in each unit in FIG. 6;

[Explanation of symbols]

 2R reception pair line 2T transmission pair line 10 main unit 20 extension telephone 30 communication adapter 40 personal computer 101-103 signal transmission transformer 201-203 signal transmission transformer 301-303 signal transmission transformer 104 line interface 206 telephone circuit unit 211 Transmission signal control unit between pairs 307 Transmission signal control unit between pairs

Continuation of the front page F term (reference) 5K030 GA19 HC14 JA08 JL09 KA13 5K032 AA04 DA11 DB12 5K034 AA10 BB06 FF09 KK02 5K049 BB05 BB17 BB19 CC08

Claims (3)

[Claims] 1. A signal transmission method for transmitting and receiving a signal by using a communication transmission line using two pairs of a transmission pair line and a reception pair line, wherein the transmission pair line and the reception pair line are provided. By applying a signal in phase to each said pair of wires,
A signal transmission method, further comprising transmitting a signal between the two pairs of pairs. 2. A communication device connected to a communication transmission line using two pairs of a transmission pair and a reception pair, wherein the transmission pair and the reception are connected. A communication device comprising: a pair-to-pair transmission signal transmission circuit that sends out a signal between a pair of wires so as to apply a signal to the pair of wires in phase. 3. A communication device connected to a communication transmission line using two pairs of a transmission pair and a reception pair, wherein the transmission pair and the reception are connected. A communication device, comprising: a pair-to-pair transmission signal receiving circuit for receiving a signal applied in-phase to each of the paired lines between the paired lines.