JP2003333204A - Modem superposing digital signal on subscriber line and telephone set therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a modem which superposes a digital signal on a subscriber line and its telephone set system not to close a loop of a telephone line during communication of a data terminal. <P>SOLUTION: The modem which is equipped with an interface accommodating a data terminal and a subscriber line interface connected as a terminal to a telephone network and communicates with opposite-side equipment by encoding and modulating data from the data terminal into a signal of a frequency band not overlapping with a frequency band for use of telephone and superposing it on the telephone network is equipped with a subscriber line interface accommodating a telephone set and a control line interface communicating control information with the telephone set; and the control line transmits notice of the start and end of communication of the data terminal to the telephone set, which recognizes a hook operation and dial button depression by a telephone set user. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to xDL (Digi).
The present invention relates to a telephone used for telephone communication that is superimposed on communication by a tally Subscriber Line) modem and its xDSL modem.

[0002]

2. Description of the Related Art In recent years, with the spread of the Internet, general households and businesses (Internet Ser
There is an increasing demand for high-speed connection with a video provider. A technique for realizing high-speed data transmission by using the conventional metallic cable as it is has been proposed in view of cost resistance.

These technologies include Digital Su
bscline Line is abbreviated as DSL, ADS
L (Asymmetric DSL), HDSL (Hi
ghbit rate DSL), IDSL (ISD
NDSL), SDSL (Symmetric DS)
L), SHDSL (Single Pair DS)
L), VDSL (Very high bit rat)
e DSL), HDSL2, etc., generally xDS
Collectively referred to as L. Also, what realizes these is a kind of modem, and the device inside the home is xTU-R (xDSL
Transceiver Unit-Remote
nd), the equipment on the telephone station side is xTU-C (xDSL T
transceiver Unit-Central o
fice), is called.

Among xDSL, ADSL and VDSL are the ones in which the conventional telephone can be used as they are. The upstream transmission speed from the home to the central office is several hundred kbits for ADSL.
/ S, and VDSL is several M to several tens Mbit / s. The transmission speed of the downlink from the Diwa station to the home is ADS.
L is several Mbit / s and VDSL is several M to several tens Mb
It / s.

These modems superimpose data on a band different from the frequency band used by existing telephones.

However, when the telephone is on-hook or off-hook, the line impedance is changed and the data transmission side is affected.

That is, if there is a change in the hook switch during data communication by the modem, the modem open communication is disconnected. In order to recover, the operating parameters of the modem have to be reset to match the new state of the line, but this recovery will take some time.

Therefore, in order to quickly adapt to changes in line impedance due to changes in the state of the telephone, ITU standard G. In 992.2 (G.Lite), the DSL modem uses the telephone side (POTS: Plain Old Tele).
A "Fast Retrain" procedure for monitoring the status change of the hook switch of the phone service) and quickly recovering when the change occurs is defined.

Further, as concrete implementations for adapting to the change in the line impedance at high speed, there are the following.

In Japanese Unexamined Patent Publication (Kokai) No. 11-289403, "Digital Subscriber Transmission System", "additional data length on the time axis of a modulated signal obtained by orthogonally amplitude-modulating a plurality of frequency-multiplexed carriers is made variable and the additional data length The control information for making variable is generated from the modulated signal received from the telephone line. "

In Japanese Unexamined Patent Publication No. 11-308334, "Digital Subscriber Transmission System", "additional data length on the time axis of a modulation signal obtained by quadrature amplitude modulation of a plurality of frequency-multiplexed carriers respectively is made variable or added. The data length is set longer than the impulse response of the line. "

These two implementations use a fixed time domain line equalizer instead of the conventional adaptive time domain line equalizer to simplify complicated parameter adjustment to cope with changes in the line state. By doing so, the response time is shortened.

Further, in Japanese Unexamined Patent Application Publication No. 11-308357, "Data Communication Device", an "on / off hook detection circuit detects a voltage level of a telephone line, and voice band communication using the telephone line is on-hook. Whether it is in a state or in an off-hook state is detected and output as a state detection signal.TEQ (Timed Domain Equalizer), FEQ (Frequency Domain Equalizer), and constellation encoder gain scaling are based on the state detection signal. By using separate tables for on-hook and off-hook, adaptive equalization, bit allocation, and gain allocation are performed in the time domain and frequency domain to perform data communication.
Since the telephone is not used when on-hook, the transmission subcarrier is expanded or shifted to a band close to the voice congested area, and further communication is performed using the voice band. "I am doing it.

[0014]

However, the above-mentioned "Fast Retrain" and Japanese Patent Laid-Open No. 11-289.
Japanese Patent No. 403 and Japanese Patent Laid-Open No. 11-308334 each attempt to shorten the recovery time. Further, Japanese Patent Application Laid-Open No. 11-308357 aims at efficiently transmitting data even if the line characteristics change.

Therefore, if the hook switch of the telephone changes during the transfer of a large file on the data communication side, the communication up to that point becomes useless, and the communication may have to be restarted from the beginning. Does not correspond to.

That is, these are all the measures taken after the line impedance has changed. This is D
This is because the SL modem cannot control on-hook / off-hook.

Japanese Patent Laid-Open No. 11-308357 only detects on-hook / off-hook by a change in line impedance.

Further, in JP-A-11-289403 and JP-A-11-308334, in order to change the additional data length which is fixed in the conventional example and the ITU standard, the opposite device is also variable. You have to deal with it.

Similarly, in Japanese Patent Application Laid-Open No. 11-308357, the opposite device must be equipped with a means for responding to the change of the table.

[0020]

According to the present invention, an interface for accommodating a data terminal and a subscriber line interface for connecting to a telephone network as a terminal are provided, and data from the data terminal does not overlap with a frequency band used by the telephone. In a modem that is coded / modulated so as to be a frequency band signal and placed on a line of a telephone network to communicate with an opposite device, a subscriber line interface that accommodates a telephone and a control line interface that communicates control information with the telephone The modem sends a communication start / end notification of the data terminal to the telephone through the control line, and the telephone recognizes the telephone user's hook operation and dial depression, and closes the loop of the telephone line during the communication of the data terminal. Since I tried to control it so that it would not tie,
It is possible to control the line impedance change to turn on-hook / off-hook at a timing that does not affect data communication.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) FIG. 1 shows a device configuration of a general system. It is roughly divided into three parts.

The first part is a telephone operator that provides telephone services, and is provided with an exchange and a line to each subscriber.

The second part is a telecommunications carrier that provides a DSL service, and has a modem for DSL communication in the office of the telephone carrier.

The third part is a general subscriber, which comprises a general telephone, a data terminal, and a modem designated by the DSL carrier.

Reference numeral 100 is a telephone operator's office, 150 is a telephone exchange, 500 is a telephone network, and 700 is a telephone that can be directly connected to the telephone network.

Reference numeral 101 is a branch for transmitting the signal on the line 501 to the AT.
It is for connecting the U-C and the telephone exchange.

Reference numeral 102 is ATU-C. In addition, by bundling a plurality of ATU-Cs, DSLAM (Digital1 S
subscriber Line Access Mul
There is also a configuration in which it is used as a multiplexer or a digital subscriber line access multiplexer.

Reference numeral 200 is an ATU-R, and 201 is a branch for connecting a signal flowing through the line 501 to the ATU-R and a telephone.

A telephone 400 is connected to the ATU-R in the house.

301 is a terminal connected to the data network,
302 is a data terminal in the house.

Reference numeral 600 is a data network such as the Internet.

A telephone call between the telephone set 700 and the telephone set 400 is carried out in the following order: in-house ← → telephone exchange, ← → telephone network ← → call partner.

Data terminal 301 and data terminal 30
The communication of No. 2 is performed in the sequence of home ← → modem installed at the telephone station ← → data network ← → communication partner.

Each block will be described with reference to FIGS. 2 to 4.

FIG. 2 is a block diagram of the ATU-C.

Reference numeral 103 is an RJ for accommodating the line 501.
-11 connector, 104 is a pulse transformer, and 105 is a driver.

Reference numeral 106 denotes an analog front end circuit,
It consists of a filter and an AD / DA converter.

An ADSL modem 107 has an interface function with an analog front end, a signal processing function such as encoding / decoding / modulation, an interface function with STM or ATM, and the like.

Reference numeral 108 is a control device composed of a CPU or the like for controlling the entire ATU-C, 109 is a storage device such as a ROM for storing a program for determining the processing of the CPU and fixed data, and 110 is a ROM. It is a rewritable memory including a RAM (including an EEPROM) for storing a program and initial data by copying and executing the operation data.

Reference numeral 111 is an Xdriver, 11
2 is RJ-45 for accommodating 10Base-T etc.
A connector, 113 is a power supply circuit, and 114 is a timing device. Note that, here, the CPU 108 has a built-in serial communication controller, and the Ethernet (R) and H
It shall be able to process DLC and ATM frames and packets.

FIG. 3 is a block diagram of the ATU-R. Basically, the ATU-C is symmetrically configured.

Reference numeral 202 denotes an RJ for accommodating the line 501.
-11 connector, 203 is a pulse transformer, 204 is a driver, and 205 is an analog front end circuit, which has a filter function and an AD / DA converter function. 206
Is an ADSL modem, which has an interface function with an analog front end, a signal processing function such as coding / decoding / modulation, and a packetizing function.

Reference numeral 207 is a control unit composed of a CPU or the like for controlling the entire ATU-R, 208 is a storage unit such as a ROM for storing a program for determining the processing of the CPU and fixed data, and 209 is a ROM. It is a rewritable memory including a RAM (including an EEPROM and the like) for copying and executing a program and initial data, and holding operation data and the like.

Reference numeral 210 is an Ethernet (R) driver, and 211 is an R for accommodating 10Base-T.
A J-45 connector, 212 is an RJ-11 connector for connecting to the telephone 400 inside the house, 213 is a power supply circuit, and 214 is a timing device.

CPU 207 similar to that of ATU-C
Shall have a built-in serial communication controller.

Thus, ATU-C and ATU-R are
Data from the RJ-11 side connected to the line 501 is sent to the Ethernet (R) side, and vice versa.
The data from the (R) side is connected to the line 501.
Transmit to J-11 side.

For layer communication on the line 501, for example,
PPP (Point To Point) is used.

FIG. 4 is a block diagram of the telephone 400.

401 is an RJ for connecting to the ATU-R
-11 connector, 402 is an incoming call detection circuit, 403 is a hook switch, 404 is a DC circuit, 405 is a power supply, 406
Is a transformer, 407 is a receiver, 408 is a human output port,
Reference numeral 409 is a control device including a CPU for controlling the entire telephone, 410 is a storage device including a ROM for storing a program for determining CPU processing and fixed data, and 411 is a program and initial data from the ROM. Copy and execute, or retain operational data. Rewritable memory such as RAM (including EEPROM) 412 is a sound source for generating a busy tone or dial tone, 413 is a clock device,
Reference numeral 414 is a speaker that outputs a ringtone or a call voice.

The telephone and the ATU-R are connected by two lines for transmitting a telephone signal and two lines for transmitting control information, a total of four lines, and the CPU 409 of the telephone 400 connects the input / output port 408. Control information can be transmitted and received via

Further, the CPU 409 uses the input / output port 40
8, the state of the hook switch 403 can be controlled, and the output to the handset or speaker can be controlled.

Here, a common software hierarchy structure of ATU-C / ATU-R / telephone will be described.

First, the base has an operating system (OS).

There is also a device driver suitable for an OS for controlling a line interface such as a telephone or Ethernet (R).

The network layer and transport layer programs are located on the upper layer, and the application program is located on the uppermost layer.

The application program initializes the device to be used and transmits and receives.

When data is received, an interrupt occurs,
The interrupt handler and the corresponding device driver part are executed and send the received data to the application. The operating system realizes these controls.

Transmission of control information between the ATU-R and the telephone is
It is performed by general start / stop communication or HDLC.

Communication of layers 3 and above may be carried out by an original protocol, and is realized by exchanging data of the format [length] / [command] / [command parameter].

By the way, this type of communication device is controlled by the state transition described below.

First, an area for holding state variables is secured in the RAM area. The initial state is called the idle state. When communication data or user operation occurs, the process for responding to it is performed and the state variable is updated. In the present invention, communication data and user operations are collectively called an event. Even for the same event, the processing differs depending on the value of the state variable. In this way, the communication protocol processing is realized.

Here, the most characteristic operation of the present invention will be described with reference to FIGS.

Each step in the flow will be referred to by one letter and three numbers.

The alphabet indicates the type of equipment, A
The TU-R process is R, and the telephone is T.

1. Description of ATU-R flow (FIG. 5) [R100: no data communication] First, it is assumed that all are in the initial state (step R100). In this state, the initialization is completed immediately after the power is turned on, and the data from the line or the data terminal can be received.

Further, the ATU-R has a network routing (layer 3) function to the ATU-C side for each data terminal inside the home. When the data communication is IP communication, the data terminal inside the home operates so that all IP packets to the subnet other than the subnet to which it belongs are sent to the ATU-R.

Here, the data terminal 302 is the data terminal 3
When data is sent to communicate with 01, A
The TU-R Ethernet (R) driver receives it and passes it to the data communication application.

In the present invention, the telephone is newly operated to notify the start / end of data communication, and
The information from the t (R) driver is received. Then, the information is recognized as an event and managed as the state of data communication.

When the data communication is started, the opposite AT
Perform processing for transfer to UC (step R1)
02). This is, for example, the link layer level establishment of ATU-R and ATU-C.

Further, the telephone is notified of the start of data communication by using the control line (step R103), and the state is changed to "with data communication" (step R20).
To 0).

[R200: With data communication] Even in this state, the event is similarly monitored (step R201), and when the end of the data communication is recognized, the process of stopping the transfer to the opposite ATU-C is performed (step R202). . This is, for example, a link layer level disconnection of ATU-R and ATU-C.

The telephone is notified of the end of data communication (step R203), and the state is changed to "no data communication" (to R200).

During the power-on period, the layer 2 is always
When establishing the link, the processes of steps R102 and R202 are not performed.

2. Description of the flow of the telephone (FIGS. 6-1 to 6-3) The telephone also performs similar state transition control.

[T100: Telephone Idle / No Data Communication] Initially, the idle state (step T10).
0). Waiting for an event (step T101), when the pick-up of the handset is detected, a dial tone is transmitted to the handset (step T102), and the value of the variable indicating the state of the hook switch is set to the value indicating "off-hook" (step T10).
3), the state is transited to [wait for telephone dial / no data communication] (to step T200).

When an incoming call is detected in step T101, a ring tone is sounded from the speaker (step T120).

At step T101, if the event is a data communication start notification, the state is changed to "telephone idle / data communication available" (to step T300).

In this event, the ATU-R recognizes the start of data communication and sends a notification (step R10).
3) because of this.

[T200: Waiting for telephone dial / no data communication] From this point onward, since it is the same as the conventional telephone communication control, description thereof will be omitted.

[T300: Telephone Idle / Data Communication Present] In this state of T300, it is assumed that the telephone is off-hook. At this time, since data communication is in progress, a busy alert is sent (step T302), the telephone circuit is not looped, the off-hook flag is set (step T303), and the state is set to [phone use restriction / data There is communication]
To (step T400).

When a call is detected in step T301, a variable indicating that the call is in the incoming state is set (step T320), and the state is transited to "telephone use restriction / with data communication" (to step T400).

When the data communication end notification is received in step T301, the state is changed to [telephone idle / no data communication] (to step T100).

[T400: Telephone use limitation / with data communication] When the state of [Telephone use limitation / with data communication] is received and an event of data communication end is received, depending on the values of the incoming flag and the hook flag, Control like.

(A) When both the hook flag and the incoming flag are set, the loop of the line is closed (step T406), and the state is transited to [during telephone call / no data communication] (to step T600).

(Ii) When the hook flag is set: The tone is changed to busy tone, dial tone is transmitted (step 404), the loop of the telephone line is closed (step T406), and the state is set to [wait for telephone dial / No data communication ”is made (step T200).

(U) When the backsend flag is set This is similar to step T120 and thereafter.

(E) If neither the hook flag nor the incoming flag is set, the state is set to [phone idle / no data communication] (to step T100).

In step T401, when the user of the telephone set 400 hangs up the receiver, the busy tone transmission is stopped (step T410), and the state of [telephone idle / data communication] is set (to step T300).

If it is not preferable to switch to dial tone transmission during busy tone transmission in step T404, a short call back ring may be made when the user picks up the receiver. Further, the control method is held in the setting memory so that the user can change it by the special number operation of the telephone.

Although various other changes can be considered, such control is similar to the control of a conventional exchange or button telephone system and will not be described further.

Here, the judgment of the start / end of the data communication will be described.

First, since the ATU-R connects the data terminal 302 and the data terminal 301 via the line 501, it can be considered as a kind of WAN router.

The router performs various controls depending on the communication contents of the data terminal. For example, if the communication is IP (Internet Protocol) communication,
Communication may be restricted depending on the TCP or UDP port number used for communication.

Here, the terminal 301 is the FTIP server, and the terminal 302 is the FTP client.
Will be performed.

FIG. 7 shows a general FTP sequence. The router, ATU-R, recognizes these sequences by looking at the contents of the IP packet, and "starts FTP" and "ends data connection".
Can be detected. Therefore, the notification of the start or end of the data communication is performed at these timings.

This is not limited to FTP, and any protocol may be used as long as the start and end are defined.

(Second Embodiment) In the first embodiment, A
The TU-R and the telephone control line communicate with each other to start / end data communication, and the CPU of the telephone controls the busy occurrence.

However, like the key telephone system,
All the events of the telephone may be notified to ATU-R so that the CPU of the ATU-R controls everything.

FIG. 8 shows a control flow of ATU-R.

In this case, since the ATU-R also manages the state of the telephone, the control takes into consideration the state of the telephone. Therefore, the telephone name is added to the state name, and if the state on the telephone side changes, the control on the ATU-R side also changes accordingly.

[R100B: Telephone Idle / No Data Communication] (FIG. 8 (1)) First, it is assumed that all are in the initial state (step R100).
B).

Here, the data terminal 302 is the data terminal 3
When data is transmitted in order to communicate with 01, a process for transferring to the opposite ATU-C is performed (step R102B), and the state is changed to [telephone idle / data communication] (to step R200B).

FIG. 9 shows a control flow of the telephone.

The telephone side manages only its own state,
Does not consider the state of data communication.

[T100B: Idle] (FIG. 9 (1)) Initially, the idle state is set. (Step T100B)
After waiting for an event (step T101B), when the handset is picked up, an off-hook event is sent to the ATU-R as control information (step T102B). And
The state is transited to "wait for off-hook acceptance" (to step T200B).

[Telephone idle / with data communication] (See FIG. 8)
(2)) It is assumed that this off-hook occurs in the state of R200B. The ATU-R sends a command for instructing busy tone output to the telephone without closing the line loop (step R202B). Then, the state is transited to [phone busy / data communication available] (step R300B).

[T200B: Waiting for off-hook reception] (FIG. 9 (2)) When a busy tone output instruction is received from the ATU-R on the telephone, in order to indicate to the user that telephone communication is unavailable. , Busyton is output from the handset or speaker (step T202B).

If the data communication is not performed, the ATU-R should return the off-hook reception, so the dial tone is output from the handset or the speaker to prepare for the user to press the dial (these). Controls are omitted in the flow diagram.).

Although ADSL is used as a concrete example in the present embodiment, it can be similarly applied to other xDSL such as VDSL shared with a telephone.

[0110]

As described above, according to the present invention,
An interface for accommodating a data terminal and a subscriber line interface for connecting to a telephone network as a terminal are provided, and data from the data terminal is coded / modulated so as to be a signal in a frequency band that does not overlap with a frequency band used by the telephone. A modem that is placed on a line of a telephone network and communicates with an opposite device is equipped with a subscriber line interface that accommodates a telephone set and a control line interface that communicates control information with the telephone set, and the modem uses a control line to communicate data terminals. The start / end notification is sent to the telephone, the telephone recognizes the telephone user's hook operation and dial depression, and controls so that the loop of the telephone line is not closed during the communication of the data terminal.
Since the line impedance change due to the hook state change is prevented during the data communication, the number of retransmissions due to the error occurrence during the data communication can be reduced and the data communication can be efficiently performed.

The control at this time is performed only inside the house, and does not require communication with an opposite modem as in Japanese Patent Laid-Open No. 11-308357.

In particular, in the second embodiment, the external line interface of the main device of the conventional key telephone system is changed to xDSL, and a part of the software of the main device is modified, so that the software on the telephone side is modified. Can be realized without any changes. This has the advantage that the manufacturer of this type of equipment can effectively utilize the assets, rather than newly creating hardware and software for controlling DSL communication and telephone communication with a single control device.

[Brief description of drawings]

FIG. 1 is a device configuration diagram of a system of the present invention.

FIG. 2 is a block diagram of ATU-C.

FIG. 3 is a block diagram of ATU-R.

FIG. 4 is a block diagram of a telephone connecting to an ATU-R.

FIG. 5 is a flow (ATU-R) of the first embodiment of the present invention.
side).

FIG. 6A is a flow chart of the first embodiment of the present invention (telephone side).

FIG. 6-2 is a flow of the first embodiment of the present invention (telephone side).

FIG. 6-3 is a flow of the first embodiment of the present invention (telephone side).

FIG. 7 shows an example of an FTP transaction.

FIG. 8 is a flow (ATU-R) of the second embodiment of the present invention.
side).

FIG. 9 is a flow of the second embodiment of the present invention (telephone side).

[Explanation of symbols]

100 Telephone operator's office 150 Telephone exchange 500 Telephone network 101 Branch 102 ATU-C 200 ATU-R 201 Branch 400 Home telephone 301 Data terminal on data network 302 Data terminal 600 at home 600 Data network 700 Telephone 202 RJ-11 Connector 203 Pulse transformer 204 Driver 205 Analog front-end circuit 206 ADSL modem 207 Control device 208 composed of CPU etc. Storage device 209 composed of ROM etc. Rewritable memory 210 composed of RAM (including EEPROM etc.) etc. Ethernet (R) driver 211 RJ-45 connector 212 RJ-11 connector 213 Power supply circuit 214 Timing device 401 RJ-11 connector 402 Incoming call detection circuit 403 Hook switch 404 DC circuit 405 Power supply 40 Trans 407 handset 408 and the like input-output port 409 storage device 411 RAM for CPU, etc. and the like configured controller 410 ROM (including EEPROM) rewritable memory 412 tone 413 timing device 414 Speaker

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5K027 AA01 AA02 BB05 BB07 EE02                       EE03                 5K034 AA19 EE12 FF04 FF05 FF06                       FF13 KK03 LL01 LL02                 5K051 AA02 AA04 BB01 BB02 CC00                       CC01 CC08 DD07 DD12 EE04                       FF02 HH01 HH02 HH16 HH26                       JJ14                 5K101 KK20 LL00 LL01 MM05 MM06                       NN32 PP06 QQ17 TT05 UU20

Claims (4)

[Claims] 1. An interface for accommodating a data terminal and a subscriber interface for connecting to a telephone network as a terminal, wherein data from the data terminal is a signal in a frequency band which does not overlap with a frequency band used by a telephone. A modem that is coded / modulated and placed on a line of a telephone network to communicate with an opposite device is equipped with a subscriber line interface for accommodating a telephone set and a control line interface for communicating control information with the telephone set. Is transmitted to the telephone, the telephone recognizes the telephone user's hook operation and dial depression, and controls so as not to close the loop of the telephone line during the communication of the data terminal. A modem and a telephone for superimposing a digital signal on a subscriber line. 2. The determination of “communication start / end of data terminal” in claim 1 is to analyze a protocol of data terminal communication. 3. The method of "controlling the loop of the telephone line not to be closed during communication of the data terminal" in claim 1 is that the telephone judges based on the communication start / end notification of the received data terminal. thing. 4. The method of "controlling the loop of a telephone line not to be closed during communication of a data terminal" according to claim 1, wherein the modem receives a state change of a hook switch of the telephone from the telephone through a control line. , It is to be controlled by the modem, such as sending the corresponding control command to the telephone.