JP3027813B2 - Communication device and communication method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device such as a data modem and a communication method, and more particularly to a communication device capable of detecting various communication system configurations for establishing a communication line and selecting an appropriate communication system configuration. The present invention relates to an apparatus and a communication method.

[0002]

2. Description of the Related Art Conventionally, data communication devices such as modems (analog and digital) have been used in public telephone networks (PST).
N: Public Switched Telepho
ne Network) has been used to transmit data from one place to another. Such modems use the conventional voice band of the PSTN (eg, about 0-4).
(KH band). Early modems transmitted data at about 300 bits per second (bps) or less over the PSTN.

[0003] Later, with the spread of the Internet, higher-speed communication systems (for example, modems) were required and developed. Currently, the highest speed analog modems available (ITU-V.100 as defined by the International Telecommunication Union (ITU)).
34 modem) is approximately 33, under ideal conditions
Data transmission is performed at a speed of 600 bps. These modems also exchange data in a band within about 4 kHz of the PSTN.

It is not uncommon to transfer data files of several megabytes (MB). Modems that operate using the 34 modulation scheme require a long time to transfer such files. As a result, demand for faster modems has increased.

[0005] Accordingly, many new communication methods have been proposed and developed for transmitting data over a local twisted wire pair using a conventional spectrum of 4 KHz or more. For example, various DSLs (Digital
A Subscriber Line (Digital Subscriber Line) modem has been developed. These are, for example, DS
L, ADSL, VDSL, HDSL, SDSL, etc., are generally called xDSL.

[0006] Some of the various xDSL systems allow simultaneous communication over a single twisted pair in the voice band and above the voice band. Since each of the various xDSLs adopts a different communication method, the uplink and the downlink,
Alternatively, the transfer speed in either one is different, and the frequency band used for the twisted pair communication channel is different.

Further, some types of xDSL require filters such as a low-pass filter, a high-pass filter, and a combination filter. These filters are sometimes referred to as splitters and may vary between devices. These filters separate the frequency band propagating voice band communication from the frequency band above the voice band propagating data communication.

[0008] The line environment surrounding the xDSL data communication system is, for example, in a conventional voice band (ie, 0-4 kHz).
z-band), the ability to coexist with conventional analog modems that communicate in the
Significantly different and complex. Therefore, in order to establish an optimal and interference-free communication line, it is indispensable to be able to determine the communication channel capability in addition to the communication device capability.

V. Conventional start-up sequences (such as the V.8 and V.8bis protocols established by the ITU-T), such as those implemented in I.34 modems, identify or identify different equipment capabilities such as the modulation scheme, protocol, etc. used. To negotiate, a bit sequence sent from each modem is used. These startup sequences apply only to conventional voice band communication methods. These conventional startup sequences do not check (or recognize) the configuration of the communication channel or line condition.

However, regarding the xDSL modem, information on line conditions, such as frequency characteristics, noise characteristics, and the presence / absence of a splitter, are negotiated by the two modems before the line is established, even if the communication line is successfully established. Sometimes useful.

Line probing techniques in the voice band are well known in the art and can be used to determine voice band line condition information. Such technology is
Certain modulation methods, e.g. 34 has been effectively used to optimize it. An apparatus having a multiplex modulation method. 8 or V.I. 8bis has been used to negotiate and select a particular modulation, and after its modulation start sequence is activated, line probing techniques are used to receive signals indicating the status of the communication channel. At this point, if it is determined that a given communication channel cannot effectively support the selected modulation method, a time consuming trial and error fallback technique is used to test the working modulation method. Was to be detected.

[0012]

Therefore, what is needed to establish a better communication line is a method of monitoring (checking) line conditions before attempting to select an optimal communication method. As described above, although a technique for increasing the data rate for a certain modulation scheme has already been established, a method using channel information to assist the selection of a communication method has not been provided conventionally.

[0013] Unfortunately, in the current state of the art, negotiation of communication capabilities is triggered without knowledge of a more efficient channel configuration. Clearly recognizing the spectrum, the splitter, and the like is indispensable for selecting an appropriate communication mechanism (modulation method).

The present invention has been made in view of the above points, and has been made in consideration of a specific (xDSL) suitable for existing line conditions.
To determine the communication standard, the various configurations, capabilities and limitations of the communication channel and associated equipment are detected. In other words, the present invention performs negotiation, exchanges of user data and inspects line characteristics without affecting the existing communication environment, and determines a communication standard and a data communication procedure suitable for the communication line. It is an object to provide a communication device and a communication method that can be determined in a short time.

[0015]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
Further, the present invention provides a first method for determining the line characteristics of a communication channel.
And the first judging means
The communication channel is determined based on the line characteristics of the communication channel.
Means for initiating high-speed data communication via the
Determine whether a splitter exists in the communication channel
And second determining means.

[0016]

According to one aspect of the present invention, a method for negotiating between modems implementing a plurality of communication methods (for example, DSL standards) and selecting one common communication standard used for communication. And an apparatus. The communication control unit executes a handshake procedure (protocol) in the negotiation channel, and acquires information on high-speed data communication including identification information of the type of xDSL used in the communication exchange. Communication standards may be de facto, proprietary, or issued by a company or government,
Applies to all types of standards.

In another aspect, the present invention provides a method for determining characteristics of a communication channel between a central office communication system and a telecommunications system using a test signal. The inspection signal detects a failure other than, for example, frequency roll-off and noise. These faults are identified and revealed between the central office system and the remote system. With the information about the communication channel quality, the present invention allows the present invention to make a more accurate decision on the choice of the continuing communication standard (for example, C instead of ADSL.
DSL or VDSL instead of CDSL).

In another aspect, the present invention provides a method and apparatus for determining the presence or absence of equipment used to separate frequency bands. In many cases, such devices are needed to communicate at frequencies above the voice band. If a separation device (splitter) to be used at that time is lacking, use of another communication method may be considered. The present invention includes a method for detecting the presence or absence of a splitter, which does not affect communication and does not interfere with any communication (such as voice communication or analog data communication) that is simultaneously performed in a voice band.

In another aspect, the present invention provides a procedure for falling back to a conventional voice band communication method when it is determined that high speed band communication is not possible. The notification signal (such as a spread processing signal) is transmitted within a conventional voice band received by the first communication control unit. The notification signal has an identification signal indicating the ability to perform data communication in a conventional voice band.

The notification signal determines whether the communication device is capable of high-speed communication even if the communication channel is not capable of high-speed communication at this time. This allows, for example, a user to purchase and install a high-speed data communication device (such as a modem), at which point the central office system automatically detects the installation of the high-speed communication device on the user side. Initiate an online procedure so that a user at the remote system can request the establishment of a high-speed communication channel using the modem.

In another embodiment of the present invention, the notification signal transmitted in the voice band (indicating that high-speed data communication is possible in the voice band or higher) is simultaneously performed in the voice band when the high-speed data communication is started. The choice is made so as not to interfere with or interrupt possible conventional communications (such as voice communications or analog data communications). The notification signal may be, for example, a spread spectrum signal generated using a pseudo-random number sequence. Alternatively, another spread spectrum technique that evenly spreads the transmission energy within the voice band may be used.

In another aspect of the invention, communication between end users, eg, exchange (transmission) of user names, passwords, etc.
Can be started over a user-only channel before communication channel testing (such as line probing) is completed and high-speed communication capabilities are exchanged. In the past, communication systems required long training (or startup) times before data was communicated between end users. According to the present invention, a test and negotiation (for a channel and a communication method) for performing high-speed communication can be performed, and at the same time, a communication path can be established.

By combining various aspects of the present invention, a method and apparatus for effectively and efficiently inspecting a communication channel and installed equipment and selecting an optimal communication method are provided. System designers, installers, and providers can set various parameters considered in the present invention during negotiations to efficiently define the optimal means of communication.

According to the present invention, determination of possible high-speed communication,
Exchange and selection of supported high-speed data communication capabilities,
Since the inspection of the communication line characteristics and the like can be executed at the same time, it is possible to immediately shift to the handshake protocol of the determined data communication procedure.

The present invention is preferably implemented on both sides of the communication channel for optimal negotiation. However, only one side of the communication channel may implement the invention. Further, one side may partially implement the present invention. Such a configuration is accurately reported to the communication system and, where appropriate, if the communication system supports conventional communication methods (such as analog), the communication system falls to those conventional communication methods. You can back.

Further, the present invention need not be implemented in an actual high-speed communication device. The present invention terminates a communication channel,
Or it can be implemented in a branching intelligent switch. This allows the communication system to accommodate various communication standards implemented in individual devices (or modems). These communication standards are precisely assigned as needed by a clear negotiation of the capabilities and requirements of the central office system and the remote systems.

According to the present invention, a method for selecting one communication standard from among a plurality of communication standards includes a procedure for examining a state of a communication channel, a condition of the inspected communication channel and each of the plurality of communication standards. Selecting a communication standard based on the capability. In the inspection of the communication channel condition, a first signal is transmitted on a communication channel of the signal, a signal for evaluating the influence of the communication channel is received, and a communication standard is selected according to the received signal. In selecting a communication standard, one xDSL is selected from a plurality of xDSL modem standards.
Select a modem standard.

According to the present invention, the communication standard capability information or user data is transmitted substantially simultaneously when checking the communication channel condition.

Further, according to the present invention, it is possible to determine whether a splitter is installed in a communication channel.

A communication device according to another aspect of the present invention includes a first communication device that transmits or receives negotiation information on a communication standard on a communication channel, and test information for determining channel characteristics of the communication channel (in different frequency bands). And a second communication device for transmitting or receiving a plurality of signals over a communication channel.

According to the present invention, the negotiation information and the inspection information are exchanged substantially at the same time. Alternatively, the negotiation information and the test information may be exchanged in different time zones.

Further, according to the present invention, the communication device can exchange a test signal on a communication channel in a predetermined frequency band, and can also exchange an optional test signal in a second frequency band.

A communication device according to another aspect of the present invention includes a first communication device for exchanging negotiation information between two sides, and a second communication device for transmitting or receiving at least user data. The negotiation information is AD
It relates to communication channel characteristics of communication standards such as SL, CDSL, and HDSL.

According to the present invention, a communication device disclosed for data exchange exchanges a fallback notification signal on a predetermined data communication band with a first communication device for exchanging negotiation information related to a predetermined data communication. And a second communication device. This fallback notification signal is used to indicate that a predetermined second communication band is available.

According to the invention, the predetermined second data communication band comprises a voice band. This voice band communication device is used when the first communication band cannot be used.

According to the present invention, even when the negotiation information and the fallback notification signal are substantially the same time zone,
Alternatively, they can be exchanged at different times.

According to the present invention, the fallback notification signal (such as a spread spectrum signal) does not interfere with other communication in the voice band.

A communication method according to another aspect of the present invention performs data exchange between a calling device and a responding device. With this method, it is determined whether a predetermined signal is detected by the responding device. A fallback procedure (such as a procedure in a voice band) is started when a predetermined signal is not detected by the responding apparatus. On the other hand, when a predetermined signal is detected,
The negotiation information is exchanged between the calling device and the responding device, and the capability between the calling device and the responding device is determined.
When the channel information is received by either the calling device or the responding device, an appropriate communication standard is selected by using at least one of the exchanged negotiation information and the received channel information, and a communication line is selected. Is established.

According to the invention, the method further comprises analyzing the received channel information and using the analyzed information in association with at least one of the exchanged negotiation information and the received channel information. , Select the appropriate information standard.

According to the present invention, user data is exchanged between the calling device and the answering device during the initialization procedure.

According to another aspect of the present invention, a disclosed data communication apparatus (such as a modem) includes means for determining line characteristics of a communication channel, and communication means based on the line means of the communication channel determined by the determination means. Means for initiating high-speed data communication on the communication channel. The notification signal indicates a high-speed data communication capability of the communication device, and is exchanged on a communication channel in a voice band.

According to the present invention, the high-speed data communication channel uses a frequency band higher than the voice band.

According to the present invention, there can be provided means for determining a communication standard of a communication device. Thus, high-speed data communication is started according to the determined communication standard and the determined line characteristics.

According to the present invention, when the determining means determines that the communication channel does not support high-speed data communication,
Means for performing data communication on a communication channel in a voice band can be provided.

Further, a communication apparatus according to another aspect of the present invention includes means for determining the presence of a splitter in a communication channel in order to maximize the capability of a communication standard.

A method according to another aspect of the present invention enables data communication by detecting the presence of a splitter in a communication channel and determines whether high speed communication is available. The presence of the splitter is detected using a signal that does not interfere with voice band communication.

Hereinafter, the present invention will be described more specifically with reference to FIGS.

FIG. 1 is a schematic block diagram of Embodiment 1 of a data communication system using a modem device. It is understood that the present invention can be applied to other communication devices without departing from the spirit and scope of the invention. Further, while the present invention has been described with reference to telephone communication systems using twisted pair wires, the present invention is not limited to cable communication systems (such as cable modems), optical communication systems, wireless systems, etc. without departing from the spirit and scope of the invention. It is understood that the present invention can be applied to other communication environments such as an infrared communication system.

The data communication system according to the first embodiment includes a central office system 2 and a remote system 4,
Both systems are interfaced via a communication channel 5.

The central office system 2 has a main distribution frame (MDF) 1 which functions as an interface between the central office system 2 and the communication channel 5. The MDF 1 has one end connected to an external telephone line (for example, communication channel 5) and the other end connected to an internal line (for example, an internal central office system line).

The remote system 4 has a network interface device (NID) 3 having an interface function between the remote system 4 and the communication channel 5. The NID 3 functions as an interface between a customer device and a communication network (for example, the communication channel 5).

FIG. 2 is a block diagram specifically showing the data communication system of FIG. 1 in the first embodiment. In the present embodiment, an example is shown in which the present invention is applied to a representative system, that is, both the central office system 2 and the remote system 4, and the remote system 4 has no splitter.

As shown in FIG. 2, the central office system 2 comprises:
A low-pass filter 34, a high-pass filter 38, a test negotiation block 46, a high-speed data receiving unit 68,
A high-speed data transmission unit 70 and a computer 82 are provided. The computer 82 functions as a general interface to network devices in the central office system. The test negotiation block 46 performs all negotiations such as line probing, which will be described later. These negotiations are performed before actual high-speed data communication.

The low-pass filter 34 and the high-pass filter 38 filter communication signals transferred via the communication channel 5. The test negotiation block 46 tests the conditions and capabilities of the central office system 2, the remote system 4, and the communication channel 5, and performs negotiation. After the procedure of the test negotiation block 46 is completed, selection of the high-speed data transmission / reception units (modems and the like) 68 and 70 is started. The high-speed data receiver receives the high-speed data transmitted from the remote system 4, while the high-speed data transmitter 70 transmits the high-speed data to the remote system 4. The high-speed data sections 68 and 70 may include an ADSL modem, a VDSL modem, a CDSL modem, or the like. In the initial negotiation procedure, the high-speed data sections 68 and 70 perform the test negotiation block 46.
May be constituted by a plurality of high-speed transmission devices that commonly use

In the present embodiment, the test negotiation block 46 includes a pseudo random noise receiving section 76,
A tone signal receiving unit 80, a user data receiving unit 60,
It includes a negotiation data reception unit 52, a user data transmission unit 62, and a negotiation data transmission unit 54.

The pseudo random noise receiving section 76 receives pseudo random noise. The tone signal receiving section 80 receives a tone signal. The user data receiving unit 60 receives the user data, and the user data transmitting unit 62 transmits the user data. The negotiation data receiving section 52 receives the negotiation data, and the negotiation data transmitting section 54 transmits the negotiation data. Details of the operation of the various parts of the central office system 2 are given below.

The user data receiving section 60, the negotiation data receiving section 52, and the high-speed data receiving section 68 transmit signals to the computer 82. User data transmission unit 6
2. The negotiation data transmitting unit 54 and the high-speed data transmitting unit 70 receive a signal transmitted from the computer 82.

The remote system 4 comprises a low-pass filter 36,
High-pass filter 40, test negotiation block 48, high-speed data receiving unit 72, and high-speed data transmitting unit 6
6 and a computer 84.

The low-pass filter 36 and the high-pass filter 40 filter communication signals transferred via the communication channel 5. The test negotiation block 48 includes the central office system 2, the remote system 4, and the communication channel 5.
Test conditions, ability, etc., and negotiate.
The high-speed data receiving section 72 receives high-speed data transmitted from the central office system 2, while the high-speed data transmitting section 66 transmits high-speed data to the central office system 2.

In the present embodiment, the test negotiation block 48 includes a pseudo-random noise generator 74,
A tone signal generator 78, a user data receiver 64,
It has a negotiation data receiving unit 56, a user data transmitting unit 58, and a negotiation data transmitting unit 50.

The pseudo-random noise generator 74 generates pseudo-random noise. The tone signal generator 78 generates a tone signal. User data receiver 64 receives user data, while user data transmitter 58 transmits user data. The negotiation data receiving unit 56 receives the negotiation data, while the negotiation data transmitting unit 50 transmits the negotiation data. The operation of each unit of the remote system 4 will be described in detail below.

The user data receiving section 64, the negotiation data receiving section 56, and the high-speed data receiving section 72 transmit signals to the computer 84. User data transmission unit 5
8. The negotiation data transmitting unit 50 and the high-speed data transmitting unit 66 receive the signal transmitted from the computer 84.

The central office system 2 comprises a plurality of channels 6,
8, 10, 12, 14, 16, 18, which comprise a plurality of channels 20, 22, 24, 2,
Used for communication with 6, 28, 30, 32. In this regard, in Embodiment 1, channel 6 communicates directly with the appropriate remote system audio channel 32 in the conventional audio band (eg, 0 Hz to about 4 kHz) filtered by low pass filters 34,36. With a central office voice channel used for Also,
The voice channel 33 on the remote system side is
Which is not under the control of the central office system 2. The audio channel 33 on the remote system side is connected in parallel with the communication channel 5 (but before the low-pass filter 36) and thus the audio channel 32 on the remote system side
Provide equivalent services. However, since the audio channel 33 on the remote system is located before the low-pass filter 36, this channel includes both the high-speed data signal and the audio signal.

By adjusting the frequency characteristics of the filters so as to be different, for example, I
Communication using another low-bandwidth communication method such as SDN can be performed. The high-pass filters 38 and 40 are selected when communicating with a frequency spectrum of 4 kHz or more.

The bit streams 8, 10, 12, 14,
16, 18 (of the central office system 2) and the bit streams 20, 22, 24, 26, 28, 30 (of the remote system 4) are used for communication between the central office computer 82 and the remote system computer 84, respectively. The digital bit stream used. Bitstreams 8, 10, 12,..., Without departing from the scope and spirit of the invention.
14, 16, and 18 are executed as a distributed signal as shown, or bundled with an interface or a cable, or multiplexed into a signal stream. For example, bit streams 8, 10, 12, 14,
16 and 18 are RS-232C, parallel, IEEE-1
394 (FireWire), USB (Universals)
al Serial Bus), wireless, or an interface conforming to the infrared (IrDA) standard. Similarly, bit streams 20, 22, 2
4, 26, 28, 30 may be implemented as distributed signals as shown, or bundled and implemented as described above.

According to the first embodiment, the user data such as the user ID and the password are stored in the user data receiving section 60 and the user data transmitting section 62 of the central office system 2 and the user data receiving section 64 of the remote system 4 and the user data. Communication (exchange) is performed between the data transmission units 58.

The user data channels 60 and 62 are low-speed communication channels, and are exchanged separately from the negotiation procedure transmitted and received by the negotiation data receiving unit 52 and the negotiation data transmitting unit 54.

Negotiation data (control information, etc.) relating to communication line conditions (frequency characteristics, noise characteristics, presence / absence of a splitter, etc.) is transmitted to negotiation data reception unit 52, negotiation data transmission unit 54, and remote system 4 of central office system 2. It is exchanged between the negotiation data receiving unit 56 and the negotiation data transmitting unit 50. In the present embodiment, these communications (negotiation communication and user communication) are performed substantially simultaneously (in parallel) using different frequency bands. However, the communication may be performed continuously in different time zones as long as the communication does not affect the scope and spirit of the present invention.

The user data channel communication does not need to have a negotiation channel correction function and is omitted as long as it does not affect the scope and spirit of the present invention. An example of data communication according to the present invention will be described with reference to FIGS. FIG. 3 is a flowchart showing the operation of the central office system 2. FIG. 4 is a flowchart showing the operation of the remote system 4. FIG. 5 is a schematic block diagram showing a frequency spectrum distribution of a signal used in the data communication system of the present invention.

In this embodiment, the central office system 2
Various communication paths for exchanging information between the remote system 4 and the remote system 4 use frequency division multiplexing (FDM). However, other techniques (CDMA, TDMA, etc.) may be used without departing from the spirit and scope of the invention.

As shown in FIG. 5, the communication path (frequency band) f1 constitutes an upstream negotiation channel. The communication path f2 (FIG. 5) forms a downstream negotiation channel. Control information relating to high-speed data communication is exchanged through uplink and downlink negotiation channels f1 and f2. The negotiation data transmitting unit 50 of the remote system 4 transmits using the frequency band f1,
Negotiation data receiving unit 52 of central office system 2
Is received using the frequency band f1. The negotiation data transmitting unit 54 of the central office system 2 transmits the channel f
2, and the negotiation data receiving unit 56 of the remote system receives data using the frequency band f2.

The communication path f 3 (FIG. 5) forms an upstream user channel for transmitting data such as a user ID and a password to the remote system 4. Communication channel f4
(FIG. 5) has a downlink user channel for receiving data such as a user ID and a password from the remote system 4. User data transmission unit 58 of remote system 4
Is transmitted in the frequency band f3, and the user data receiving unit 60 of the central office system 2 receives in the frequency band f3. The user data transmitting unit 62 of the central office system 2 transmits the downlink of the channel f4, and the user data receiving unit 64 of the remote system 4 receives the frequency band f4. As described above, information exchange between the negotiation channel and the user channel is performed independently of each other.

In the present embodiment, the frequency bands of the communication paths (negotiation channels) f1 and f2 are lower than the frequency bands of the communication paths (user channels) f3 and f4. The lower frequency is used for the negotiation channel because it is desirable for the system based on the observation that the lower the frequency, the lower the error rate. However, such allocation of the bands (along with the actual frequency bands of the various communication paths) can be varied without departing from the spirit and scope of the present invention.

The channel inspection signal is transmitted to determine the communication capability of the established communication line (connection). If the test signal has a plurality of signal groups, it is desirable that each test signal group be transmitted independently. In the present embodiment, there are two signal groups: (1) a basic channel test signal and (2) an optional channel test signal.

The communication path f5 (FIG. 5) has a basic channel test signal band for transmitting a basic channel test signal for determining the channel characteristics of a communication channel. Similarly, the communication path f
6 (FIG. 6) has an optional channel inspection signal band for optionally transmitting an optional channel inspection signal in a frequency band higher than the frequency band of the communication path f5. The tone signal generator 78 of the remote system 4 generates a test signal transmitted on the communication paths f5 and f6. The tone signal receiving unit 80 of the central office system 2 has a communication path f5
And an inspection signal is received at f6. The transmission of the basic channel test signal and the option channel test signal is started at different timings.

In the present embodiment, the test signal comprises a signal of a specific sine tone group. The specific configuration of the test signal can be changed without departing from the scope and spirit of the present invention. For example, the test signal may be composed of a plurality of frequencies, a plurality of signals, a wide area signal, a noise signal (such as white noise in a specific band) or a pure sine group including a spread spectrum signal. Further, the inspection signal may be composed of a plurality of signal groups transmitted in sub-frequency bands of different frequencies. Further, when the inspection signal is composed of a plurality of signal groups, the phases of the signals may be different.

The basic channel check signal is transmitted at the start of communication connection. It is desirable to determine whether or not the optional channel test signal (for example, the test signal transmitted in the optional channel test signal band f6) can execute data communication in a frequency band higher than the frequency band of the basic channel test signal band. Sent only if However, transmission of the optional channel test signal may be started simultaneously with the basic channel test signal without departing from the scope and spirit of the present invention.

The pseudo-random noise generator 74 (FIG. 2) of the remote system 4 transmits a notification signal in a voice band (about 0 to 4 kHz) as shown in FIG. The notification signal detects the presence of the splitter and the capability notification function using the voice band. This capability notification function indicates that at least one of high-speed data communication and voice communication is available. Regarding the frequency (spectrum) of the notification signal, use of a specific frequency signal (or FM modulation signal) is not preferable. For example, T.C. for facsimile connection. CNG signal in 30 protocols,
V. The CI signal or the like in the 8 protocol generates an audible signal that interferes with ongoing voice band communication. Therefore, in the present embodiment, it is preferable that the notification signal is a spread spectrum signal such as pseudo random noise. However, other types of signals can be used. By using a spread spectrum signal having an appropriate power value, reception of a signal that interferes with voice communication can be prevented.

In the present embodiment, the notification signal has a display signal indicating that the data communication capability is available in the voice band. By this display signal, another communication terminal (for example,
The central office system 2) when the remote system is sending the display signal can identify whether the high speed data communication function is available.

The notification signal can be further used to identify whether the communication system uses a frequency separation unit (such as a splitter). In a communication system, a splitter is used to prevent receiving a voice band signal when a communication device is connected to a high frequency port. Therefore, the absence of the notification signal indicates that the splitter is installed in the communication system.

The following will be described with reference to the flowcharts of FIGS. Since there are several decision branches in the flow chart, various combinations of steps are possible.
First, a schematic flow (that is, a straight flow) will be described, and then a flow involving a branch will be described. The path in the procedure (flowchart) depends on the equipment arrangement (for example, whether the splitter is in the communication path, both sides have the invention, whether external interference does not degrade the quality of the communication channel 5, etc.). Since the flow describes the negotiation between related communication devices, the operation of each related device is the ping-pong (zigzag) between FIG. 3 and FIG.
Described in the scheme. FIG. 3 shows the processing by the test negotiation block 46 of the central office system 2.
Is the test negotiation block 4 of the remote system 4
8.

In step (hereinafter abbreviated as ST) 200, a pilot tone signal of a predetermined frequency is transmitted by negotiation data transmitting section 50 of remote system 4. At the same time, pseudo-random noise is transmitted by the pseudo-random noise generator 74.

In ST202, central office system 2
Uses the negotiation data receiving unit 52 to inspect the negotiation uplink band and determine whether an uplink pilot signal is being transmitted. When the negotiation uplink data pilot signal is detected, the central office system 2
The transmission of the downlink negotiation pilot signal is started using the negotiation data transmission unit 54.

In ST208, remote system 4 determines whether or not a downlink pilot tone signal has been detected. In ST208, when a downlink pilot tone signal is detected by remote system 4, ST212 is executed, and negotiation data transmitting section 50 starts transmission of uplink negotiation data via uplink negotiation channel f1.

In ST214, when central office system 2 detects valid data, negotiation data transmitting section 54 starts transmission of downlink negotiation data via downlink negotiation channel f2. On the other hand, when the central office system 2 does not detect valid data, the data detection operation is repeatedly performed.

In ST218, remote system 4 determines whether valid negotiation downlink data has been detected. When the remote system 4 detects valid data, the user data transmission unit 58 of the remote system 4 starts transmitting uplink user data via the uplink user channel f3 (ST220). On the other hand, if remote system 4 fails to detect valid data, ST 218 is repeated until valid data is detected.

The remote system 4 also transmits a basic channel test signal (ST222) in the frequency band f5 (for example, a basic channel test signal channel). In response to this signal,
The central office system 2 starts checking the line characteristics.

The central office system 2 includes a user data receiving unit 6
It is determined whether valid uplink user data is detected at 0 (ST224). If the result of ST224 is negative, this step is repeatedly performed until a positive result is obtained. At that point, the process moves to ST226,
The user data transmission unit 62 starts transmitting downlink user data via the downlink user channel f4.

Next, ST 228 is executed, and tone signal receiving section 80 of central office system 2 starts receiving the basic channel check signal transmitted by tone signal generating section 78 of remote system 4.

In remote system 4, user data receiving section 64 determines whether or not valid downlink user data has been received (ST230). If the determination result is negative, ST230 is executed again until a positive result is obtained.
When the remote system 4 receives valid downlink user data (eg, a positive determination result), all communication channels have been established.

At this point, ST232 is executed, and remote system 4 repeatedly transmits its communication capability and communication method information via the upstream negotiation path. At the same time, ST234 is executed, and the central office system 2 starts transmitting its communication capability and desired communication conditions (for example, an indication that the optional channel test signal information band f6 (ST236) can be used).

When the remote system 4 receives from the central office system an indication permitting the use of the optional channel test signal (ST236 is affirmative), the tone generator 78 of the remote system 4 starts transmitting the optional channel test signal. (ST238). On the other hand, if ST236 is negative, the process proceeds to ST244.

In the meantime, the tone signal receiving section 80 of the central office system 2 performs spectrum analysis of the signal to calculate the spectrum information (ST240), and the spectrum information is then transmitted via the downstream negotiation path f2 to the remote system 4. (ST242).

Remote system 4 waits in ST 244 until it determines that spectrum information has been received. When the spectrum information is received, the remote system 4 performs the analysis, determines the capability, the channel limitation, and the like, and makes the final determination on the type of communication method (standard) to be used (for example, ADSL, CDSL, etc.) (ST246) ). Next, the remote system 4 stops transmitting the basic channel test signal (and the optional channel test signal, if transmitted) (ST248). The remote system 4 transmits (indicates) information related to the final determination (in the upstream negotiation path f).
1) (ST250).

Central office system 2 stands by until it is determined that information on the final determination has been received from remote system 4 (ST252). When central office system 2 detects the reception of the final determination, ST 254 is executed, and the transmission of downlink negotiation data and downlink user data is stopped.

On the remote system 4 side, the remote system 4 waits until energy (carrier) attenuation is detected, at which point the transmission of uplink negotiation data and uplink user data is stopped (ST258). Thereafter, the remote system 4 waits until the predetermined period ends (ST260), and thereafter, initialization of the procedure of the selected high-speed communication system type is started. After the negotiation procedure and the fast initialization procedure are completed, a suitable high-speed communication channel between the central office system 2 and the remote system 4 is available.

The tone signal receiving section 80 of the central office system 2
However, when the pilot tone signal cannot be detected in ST202, the pseudo random noise receiving unit 7 of the central office system 2
No. 6 judges in step ST204 whether or not pseudorandom noise in a voice band of about 0 Hz to 4 kHz exists (is detected). When the pseudo random noise is detected, the conventional voice band data communication can be executed (ST206), and it is determined that the channel cannot support the high-speed communication but the device can support the high-speed communication. That is, the present invention relates to 8, V.I. 8bis, V.I. It is determined that a conventional fallback communication connection of the voice band such as the 34 protocol is performed. If no pseudo random noise is detected, ST20
2 is re-executed to detect the pilot tone signal again. As described above, it is possible to determine whether or not the high-speed data communication function can be used by transmitting a notification signal (pseudo random noise or the like) within the voice band and determining whether the notification signal can be received.

However, if the high-speed data communication cannot be performed, the present invention falls back to the voice band communication procedure. For example, when high-speed data communication is not executed, Data communication can be performed using the H.34 protocol. If a downlink pilot tone signal is not detected in ST208, ST210
Is executed, and the remote system 4 executes the voice band procedure (V.8,
V. 8bis) or an alternative fast procedure.

In summary, negotiation block 4
6 and 48 analyze the communication channel and associated equipment (on both the central office system side and the remote system side)
Select an appropriate communication standard.

FIG. 6 shows a conceptual diagram of an apparatus according to Embodiment 1 of the present invention. The central office system splitter 304
Each block of the test negotiation block 46 shown in FIG.
-Supply signals to modems 68 and 70, shown at C302. PSTN switch 300 is connected to channel 5. Telephone 306 is conveniently connected to voice channel 33 shown in FIG. However, telephone 306 may connect to voice channel 32 without departing from the scope and spirit of the present invention. Various modifications can be made to the present embodiment. 7 to 12
Shows a modified schematic block diagram, but the invention is not limited to this embodiment. The same components as those in the first embodiment are denoted by the same reference numerals.

FIGS. 7 and 8 show a second embodiment of the present invention. In the present embodiment, the present invention is implemented only in the remote system 4, and the central office system 2 is not compatible with high-speed communication. When remote system 4 attempts to connect to central office system 2, a downlink pilot signal cannot be detected in ST208 (FIG. 4). As a result, a voice procedure is started in ST210. As shown in FIG.
4 shows a voice band signal transmitted to the N switch 300.

Although not shown, as a modification of the present embodiment, it is conceivable that the central office system 2 implements the present invention and the remote system terminal 4 does not use high-speed data communication.

In this situation, the central station system 2
At 202, when an uplink pilot tone cannot be detected, but when a pseudo random number signal is detected, a voice band procedure is started at ST206. Similarly, if the central office system 2 cannot detect an uplink pilot tone in ST202 and cannot detect a pseudo random number signal in ST204, the central office system 2 starts a voice band procedure after a predetermined time. 9 and 10 show a third embodiment of the present invention. This embodiment is implemented in that a remote system splitter 86 is provided in the remote system 4 in order to separate the x-type transmission unit (xTU-R) 350 on the remote system side from the telephone (network) 306. Embodiment 1 is different from Embodiment 1. In this configuration, the use of the splitter 86 significantly reduces the interference between the high-speed band and the voice band spectrum, and the xTU0C (302) and xTU-R (3)
The performance of 50) is improved. As shown in FIG. 10, the splitter 86 includes a low-pass filter 88 and a high-pass filter 90.

In this embodiment, the pseudo random noise does not pass through the high-pass filter 90. Thus, the pseudo-random noise receiver 76 of the central office system 2 will not receive the pseudo-random noise generated by the remote system 4, which indicates that a splitter is present. This information is exchanged during the negotiation period. As a result, the detection of the splitter filter is automatically performed and displayed.

In the present embodiment, telephone 306 (FIG. 9) is connected to channel 33 (FIG. 10). The configuration of the central office system 2 in FIG. 9 is the same as the configuration of the central office system 2 in FIG.

FIG. 11 shows a fourth embodiment of the present invention. In the present embodiment, the intelligent switch 314
Has the function performed in the test negotiation block 46 and has the appropriate xTU-C (316 or 318).
Etc.) and the selected communication standard (ADSL, VDS
L, ISDN, V.L. 34 etc.) are established.

FIG. 12 shows a fifth embodiment of the present invention. In the present embodiment, the central office system 2 is divided into a plurality of parts (for example, a first part 320 and a second part 322), and the communication operation can be performed by a plurality of service providers. The configuration of each part is essentially the same as the configuration shown in FIG. First part 320 and second part 322
Is configured similarly to any of the above-described embodiments. As already mentioned, splitters 304 and 328
Is installed to separate voice band signals from high speed communication.

According to the present embodiment, the public switched telephone network (PSTN) switches 300 and 326 and the xTU-C
The units 302 and 330 are configured by a service provider that provides a specific service. When the remote system initiates a request for service, only those systems that can provide the desired service (as determined by the upstream negotiation data corresponding to the transmission of the downstream negotiation data) are connected to the remote system.

According to the present invention, the optimum communication standard to be used is determined quickly and effectively from a plurality of communication standards. In particular, in the present invention, it is possible to efficiently select one communication standard from a plurality of communication standards, determine and clarify the channel characteristics, use the channel characteristics, and reasonably determine the presence or absence of a splitter in a communication path. These allow user data to be exchanged between the central office system and the remote system before a high speed communication path becomes available.

In the present invention, the data communication may be started at the same time as the negotiation procedure. That is, user communication (such as data communication) can be performed at the same time as the line inspection and the negotiation operation. However, the transmission of the user communication can also be started after performing the negotiation operation without departing from the spirit and scope of the present invention.

Although the invention has been described with reference to particular means, materials, and equipment, the invention is not limited to what is disclosed herein, but applies to any equivalent situation as set forth in the following claims. For example, the computers 82 and 84 can be replaced by another device (such as a network device) that generates a data signal transmitted via the communication channel 5.

[0112]

As is apparent from the above description, according to the present invention, it is possible to perform the communication without affecting the existing communication environment.
Negotiation and exchange of user data are performed between two communication systems, and at the same time, line characteristics are inspected, and a communication standard and a data communication procedure suitable for a communication line can be determined in a short time.

[Brief description of the drawings]

FIG. 1 is a block diagram of a data communication system using a communication device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration of the data communication system according to the first embodiment.

FIG. 3 is a flowchart showing an operation on the central office system side of the data communication system according to the first embodiment.

FIG. 4 is a flowchart showing an operation on the remote system side of the data communication system according to the first embodiment;

FIG. 5 is a schematic diagram showing a spectrum distribution used in the data communication system according to the first embodiment.

FIG. 6 is a schematic block diagram showing a data communication system according to the first embodiment.

FIG. 7 is a schematic block diagram showing a data communication system using a communication device according to a second embodiment of the present invention.

FIG. 8 is a block diagram showing a specific configuration of a data communication system according to a second embodiment.

FIG. 9 is a schematic block diagram showing a data communication system using a communication device according to a third embodiment of the present invention.

FIG. 10 is a block diagram showing a specific configuration of a data communication system according to a third embodiment.

FIG. 11 is a schematic block diagram of a data communication system using a communication device according to a fourth embodiment of the present invention.

FIG. 12 is a schematic block diagram of a data communication system using a communication device according to a fifth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 Main distribution frame (MDF) 2 Central office system 3 Network interface device (NID) 4 Remote system 5 Communication channel 34, 36 Low-pass filter 38, 40 High-pass filter 46, 48 Test negotiation block

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-51328 (JP, A) JP-A-10-75279 (JP, A) US Patent 5400322 (US, A) US Patent 5479447 (US, A) US Patent 5,805,669 (US, A) Nikkei Communication NO. 252, p. 81-89 (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 29/06 H04J 11/00 H04L 27/34 H04L 29/08 H04M 11/00 303

Claims (9)

(57) [Claims] 1. A first method for determining line characteristics of a communication channel.
And the first judging means
The communication channel is determined based on the line characteristics of the communication channel.
Means for initiating high-speed data communication via the
Determine whether a splitter exists in the communication channel
Communication device, comprising:
Place. 2. A second determination for determining the presence of a splitter
The measures are characterized in that they allow the performance of the communication standard to be optimized.
The communication device according to claim 1, wherein the communication device comprises: 3. The high-speed data communication uses a frequency higher than the voice band.
2. The communication device according to claim 1, wherein several bands are used.
Place. 4. A means for determining a communication standard of a communication device.
The high-speed data communication includes the determined communication.
Starting according to communication standards and line characteristics.
The communication device according to claim 1. 5. The communication device according to claim 1, wherein the determining means determines that the communication channel is a high-speed data
Communication is not supported if it is determined that
Means for performing data communication via the channel.
The communication device according to claim 1, wherein 6. The communication device includes a modem.
The communication device according to claim 1. 7. A communication indicating a high-speed data communication capability of a communication device.
Means for exchanging knowledge signals over voice band communication channels
The communication device according to claim 1, further comprising: 8. A communication method for enabling data communication.
Detecting the presence of the splitter in the communication channel,
Determines whether high-speed communication is available
Communication method. 9. A method for determining the presence of said splitter.
And has characteristics that do not interfere with voice band communication
9. A signal is emitted.
Communication method.