JP2003333205A - Modem superposing digital signal on subscriber line, and telephone set and dial system conversion thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce influence of dial pulses on xDSL communication superposed on telephone. <P>SOLUTION: A modem which is equipped with an interface accommodating a data terminal, an interface accommodating a telephone set through a telephone line, and an interface connected to a telephone switching 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 used for telephone and superposing it on a telephone line and using a branching filter separating data communication and telephone communication is equipped with a means of detecting a calling PB signal (multi- frequency signal) from the telephone line and a means of sending dial pulses out and converts the calling PB signal (multi-frequency signal) from the telephone set into corresponding dial pulses and sends them out to an exchange. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to xDSL (Dig).
The present invention relates to an extended function of a modulation / demodulation device called an “ital Subscriber Line” modem.
The extended function is to convert the dial system at the time of calling of the telephone communication by the xDSL modem when the telephone communication is superimposed on the data communication by the 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 Vice Provider). From the viewpoint of cost, a technique has been proposed for realizing high-speed data transmission by using the metallic cable that has been conventionally used for telephone communication as it is.

These technologies include Digital Su
bscriber Line is abbreviated as DSL, and AD
SL (Asymmetric DSL), HDSL (H
high bit rate DSL), IDSL (IS
DN DSL), SDSL (Symetric DS)
L), SHDSL (Single Pair DS)
L), VDSL (Very high bit rat)
e DLS), HDSL2, etc., generally x
Collectively referred to as DSL.

[0006] Also, what realizes these is a modulation / demodulation device (modem), and the device inside the home is xTU-R (xD
SL Transceiver Unit-Remote
end), the equipment on the telephone station side is xTU-C (xDSL
TransceiverUnit-Central
office).

Among the xDSL, the ones that can coexist with the conventional telephone are ADSL and VDSL.

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

However, when a telephone generates a dial pulse, it causes a change in line impedance, affects data transmission between modems, and sometimes breaks the communication link.

To recover from this fault, the operating parameters of the modem must be reset to match the new impedance state of the line, but this process takes a considerable amount of time.

ITU standard G. 992.2 (G.Lit
In e), the DSL modem uses the telephone side (POTS: Pla).
in Old Telephone Service)
"Fast Retrai", a procedure to monitor the status change of the hook switch and quickly recover when the change occurs.
n) "is defined.

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

Japanese Unexamined Patent Publication No. 11-289403 discloses a "digital subscriber transmission system" in which the additional data length on the time axis of a modulation signal obtained by quadrature amplitude modulating a plurality of frequency-multiplexed carriers is made variable. 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. "

In these two implementations, a fixed time domain line equalizer is used instead of the conventional adaptive time domain line equalizer to simplify complicated parameter adjustment to cope with a change 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 during on-hook, the transmission subcarrier is expanded or shifted to a band close to this voice band, and further communication is performed using the voice band. "I am doing it.

[0015]

However, the above-mentioned "Fast Retraim" and Japanese Unexamined Patent Application Publication 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.

Even when the state is changed from off-hook to on-hook only once, such as when disconnecting a call, the above-mentioned conventional example has some effect of reducing the failure time.

However, in the case of making a call by dial pulse, the change state of the hook switch continues until the transmission of the last digit of the telephone number is completed. For example, 20PPS (P
ulse Per Second) environment, 1
It takes 10/20 = 0.5 seconds to dial a "0" (zero) consisting of zero pulses. Considering human operation intervals, it takes about 10 seconds to send a telephone number of 5 to 11 digits. During this time, the data transmission side is affected.

That is, the conventional example is a countermeasure after the line impedance changes, and does not correspond to the fact that the impedance change continues for a long time like dialing at the time of calling.

Further, Japanese Patent Laid-Open Nos. 11-289403 and 11-308334 correspond to that the opposite device is also variable in order to change the additional data length which is fixed in the ITU standard. You have to do it.

Similarly, in Japanese Laid-Open Patent Publication No. 11-308357, the device on the opposite side must be provided with means for responding to the change of the table.

[0021]

SUMMARY OF THE INVENTION The present invention comprises an interface for accommodating a data terminal, an interface for accommodating a telephone via a telephone line, and an interface for connecting to a telephone exchange, and a frequency band used by the telephone. In a modem that communicates with the opposite device by using a duplexer that encodes / modulates the data from the data terminal and places it on the telephone line so that the signals have frequency bands that do not overlap, A means for detecting a calling PB signal (multi-frequency signal) from the telephone line and a means for sending a dial pulse are provided, and the calling PB signal (multi-frequency signal) from the telephone is converted into a corresponding dial pulse. Since it was sent out to the exchange, only by the correspondence on the xTU-C side,
It is possible to make a call by the dial palace contract without affecting the data communication.

[0022]

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 company 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 xDSL 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 xDSL carrier.

Reference numeral 100 is a telephone company office, 150 is a telephone exchange, 500 is a telephone network, and 701 is a telephone that can be directly connected to the telephone network.

Reference numeral 102 is ATU-C. In addition, by bundling a plurality of ATU-Cs, DSLAM (Digital 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.

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.

Reference numeral 702 is a telephone that can be directly connected to the telephone network and is placed in the house.

A telephone call between the telephone 701 and the telephone 702 is carried out in the sequence of in-house ← → exchange of telephone office ← → telephone network ← → other party.

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.

It is assumed that the user of the telephone 702 has a dial pulse calling contract with the telephone carrier over the line 501.

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

FIG. 2 is a block diagram of the ATU-C (102).

101 is an R for connecting to the line 501
A J-11 connector, 116 is an interface for accommodating the telephone 702 via the line 501, 117 is a band pass filter for separately extracting a telephone signal and a DSL modem signal from the signal from the line 501, and P
A splitter that also detects B signals (multi-frequency signals), 115 is an interface that sends dial pulses to the exchange, detects polarity reversal of the exchange, and detects incoming signals,
103 is a connector for connecting to an exchange, 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 coding / decoding / modulation, and an interface function with STM or ATM.

Reference numeral 108 denotes a control device including 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 and the like) for copying and executing a program and initial data, and holding operation data and the like.

Reference numeral 111 is an Ethernet (R) driver, 112 is an RJ-45 connector for accommodating a 10 / 100Base-T, etc., 113 is a power supply circuit, 114
Is a time measuring device for generating a time-out or measuring a time.

Note that, here, the CPU 108 has a built-in serial communication controller, and the Ethernet
(R), HDLC, and ATM frames and packets can be processed.

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 device composed of a CPU or the like for controlling the ATW / temperature overall, 208 is a storage device 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, 211 is an RJ-45 connector for accommodating a 10 / 100Base-T, etc., 212 is an RJ-45 connector for connecting to a telephone 702 inside the home, and 213 is a power supply. A circuit, 214 is a timing device.

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

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

For layer 2 communication on the line 501, for example, PPP (Point To Point Prot) is used.
ocol ”is used.

FIG. 4 is a block diagram of telephones 701 and 702.

401 is an RJ- for connecting to a telephone line.
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 an input / output port, 4
Reference numeral 09 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. R to copy and execute, or to retain operational data
Rewritable memory such as AM (including EEPROM), 412 is a sound source for generating busy tone, dial tone, PB signal, etc., 413 is a time measuring device, and 414 is a speaker for outputting ring tone or call voice. .

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

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

A device driver for controlling a line interface such as a telephone or Ethernet (R) is
It is installed in a form compatible with the OS.

A program for processing a protocol of the network layer and a protocol of the transvote layer is provided on the upper layer, and an application program is provided 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.

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

First, an area for holding a state variable is secured in the RAM frame 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 if the same event of data reception occurs, the processing for it depends on the value of the state variable.

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

Each step in the flow will be referred to by one letter and three numbers. The alphabet indicates the seed price of the device, and the processing of ATU-C is C. 1. Description of ATU-C flow (Fig. 5-1 to Fig. 5-
2) [C100: Idle] First, it is assumed that all are in the initial state (step C100). 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.

Here, if the user of the telephone 702 goes off-hook, the ATU-C interface detects it and closes the loop for the exchange (step C102). Subsequently, the COT I / F 115 and the SLT are connected so that the line on the telephone side and the line on the exchange side are connected.
Connect the communication path with the I / F 116 (step C10
3), the state is set to the dial waiting state (step C20).
To 0).

[C200: Waiting for dial] <PB dial detection> Even in this state, the event is similarly monitored (step C201). Splitter 11
When 7 detects the PB component in the signal from the telephone, CP
U108 controls the COT I / F to send a dial pulse corresponding to the PB signal to the exchange (step C).
202). Then, start the timer (step C
203). At this time, the state remains the same.

<Timer expiration event> Step C20
When the timer has expired at 0, the state is changed to talking (step C300).

Although not shown in the flow chart, when the PB signal is received from the telephone at the stage after the call in step C300, it is sent to the exchange side as it is.

(Second Embodiment) The second embodiment is a method in which an event to be transited during a call is a signal component from the 99 exchange side.

These include the following:

(A) Voice component in signal This is to judge that "the user of the telephone 701 responded and uttered some voice".

(Ii) Stop of RBT (ring back tone) This is because it is judged that the user of the telephone 701 has responded, "the exchange has detected and stopped sending the RBT to the ATU-C." is there.

(Third Embodiment) In the third embodiment, an event to be transited during a call is performed by "reversing the polarity of the line on the exchange side".

This is a case where an exchange is used which transmits the response of the called side to the calling side by reversing the polarity.

In the present embodiment, ADSL is used as a concrete example, but the same can be applied to other xDSL such as VDSL shared with a telephone.

[0073]

As described above, according to the present invention,
The data from the data terminal has an interface for accommodating the data terminal, an interface for accommodating the telephone through the telephone line, and an interface for connecting to the telephone exchange, and has a frequency band signal that does not overlap with the frequency band used by the telephone. A PB for calling from a telephone line in a modem that encodes / modulates data on a telephone line and uses a duplexer that separates data communication and telephone communication to communicate with an opposite device
A means for detecting a signal (multi-frequency signal) and a means for sending a dial pulse are provided, and the calling PB signal (multi-frequency signal) from the telephone is converted into a corresponding dial pulse and sent to the exchange. Therefore, the line impedance fluctuation unlike dial pulse calling does not occur and the data communication can be stably performed. The control at this time is performed only on the telephone station side.
Since communication with an opposite modem is not required unlike 7 and the like, the load of the system and the communication amount of control information can be reduced.

If the dial pulse transmission contract is PB
If it is applied to a telephone line that is cheaper than the outgoing contract, the line contract fee can be reduced.

[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] Block diagram of Oni∬V Ichion.

FIG. 4 is a block diagram of a telephone used in the system of the present invention.

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

[Explanation of symbols]

100 Telephone operator's office 102 ATU-C 103 Connector 104 Pulse transformer 105 Driver 106 Analog front end circuit 107 ADSL modem 108 Control device 109 including CPU 109 Storage device 110 including ROM 110 RAM (including EEPROM) Rewritable memory 111 including Ethernet (R) driver 112 RJ-45 connector 113 power supply circuit 114 timing device 115 interface 116 interface 150 telephone exchange 200 ATU-R 201 branch 301 data terminal on data network 302 data terminal 500 at home telephone Network 600 data network 702 home telephone 701 telephone

Continued front page    F-term (reference) 5K004 AA06 GC01                 5K027 AA01 AA02 BB07 BB12 CC01                       EE03 EE12 EE13 EE14                 5K051 AA04 BB01 BB02 CC00 CC01                       DD07 DD12 EE04 FF02 HH01                       HH18 HH22 JJ02                 5K101 KK20 LL00 LL01 MM05 MM06                       NN02 NN34 PP06 QQ17 UU03

Claims (5)

[Claims] 1. An interface for accommodating a data terminal, an interface for accommodating a telephone via a telephone line, and an interface for connecting to a telephone exchange, so that a signal in a frequency band that does not overlap with a frequency band used by a telephone is provided. In a modem that communicates with an opposite device by using a duplexer that encodes / modulates data from a data terminal and places it on a telephone line to separate data communication and telephone communication, a PB signal for calling (multifrequency signal) from the telephone line ) Detecting means and dial pulse sending means, and converting the calling PB signal (multi-frequency signal) from the telephone into a corresponding dial pulse and sending it to the exchange. The dial system conversion of the modem and the telephone that superimposes the digital signal on the. 2. The demultiplexer according to claim 1, wherein the duplexer also serves as means for detecting a calling PB signal (multifrequency signal) from a telephone line. 3. The "means for detecting a calling PB signal (multi-frequency signal) from a telephone line" in claim 1 is characterized by detecting elapse of a fixed time. 4. The "means for detecting a calling PB signal (multi-frequency signal) from a telephone line" in claim 1 is characterized by analyzing a signal from an exchange. 5. The "means for detecting a calling PB signal (multi-frequency signal) from a telephone line" in claim 1 is characterized by detecting a polarity reversal of a line connected to an exchange.