JPH0740708B2 - Redial control system - Google Patents

Description

DETAILED DESCRIPTION [Overview] A signal quality detection circuit (SQ) for detecting the quality of a received signal in a redial control system using an AA type NCU built-in modem.
D) is provided, the line is disconnected when the deterioration of the received signal is detected, and the modem automatically redials based on the redial instruction parameter in the automatic call command.
As a result, even if the line is disconnected due to deterioration of the line condition, redial can be automatically performed.

[Industrial application field]

The present invention relates to a redial control method for a modem,
The present invention relates to a redial control method for a modem with a built-in outgoing / incoming automatic network controller (AA type NCU).

Modem (MODEM) for analog transmission of digital signals from data terminal equipment (DTE) using telephone lines.
Is used to perform mutual conversion between digital signals and analog signals, and the network control unit (NCU: Network) built into the model.
The control unit) controls the connection with the switching network, the connection between the DTE and the telephone line, and the generation of dial signals as in the case of a normal telephone. Both dial pulse signals (DP signals) and push button dial signals (PB signals) are used as dial signal formats.

For connection control for 1 line by NCU, manual type NCU (MM type NCU) used in the case of 1 line manual outgoing / incoming connection type,
There are semi-automatic NCU (MA type NCU) used in the case of 1 line manual transmission and automatic incoming connection type and automatic type NCU (AA type NCU) used in the case of 1 line automatic outgoing / incoming connection type.

The present invention, in these AA type NCU built-in modem,
The present invention relates to a redial control method when making a line connection.

[Conventional technology]

Referring to FIG. 4, a redial control system by a conventional modem with built-in AA type NCU will be described. FIG. 4 shows the line structure of the conventional DTE and modem.

In FIG. 4, 21 is the entire AA type NCU built-in modem, 211
Is a modem unit, and 212 is an AA type NCU (hereinafter referred to as NCU)
Is.

22 is a DTE, 23 is a terminal interface, and 24 is a telephone line. The telephone line is connected to a telephone exchange network (not shown), and the terminal interface 23 uses RS-232C.

In this configuration, when the DTE 22 performs data communication with the partner station, automatic dialing is performed by transmitting the character of the dial number to the NCU 212 and the modem 211 section via the terminal interface 23.

Now, for example, in ASCII code dial number D774111 (D
Indicates a dial signal, and 774111 indicates a telephone number), the NCU 212 dials the telephone number 774111 in the ASCII code to automatically make a call.

When the line with the partner station is connected and the handshake with the partner station succeeds, the data communication mode is set and data communication between the DTE 22 and the partner station is performed.

When the partner station is communicating during the line connection control operation by the NCU 212, the modem unit 211 instructs the NCU 212 to redial a predetermined number of times so that the line connection with the partner station is successful.

If you connect to the partner station correctly, if the connected line status is bad (for example, there is a lot of noise), handshaking does not succeed, or if the line status deteriorates during communication and many errors occur, communication will be interrupted. The line may be disconnected at.

In this way, when the line is disconnected again during the line connection with the same partner station, the same connection control procedure starting from the call is restarted from the beginning, and the operation to reconnect with the partner station is performed. Done.

[Problems to be solved by the invention]

In the conventional line connection method using the AA NCU built-in modem, when connecting to the partner station, if the signal quality deteriorates due to the deterioration of the line condition, the line may be disconnected during the communication. When reconnecting with a station, the connection process with the other station had to be restarted from the beginning.

Therefore, if the line is disconnected during communication due to the deterioration of the line condition, there is a problem that the reconnection process takes time and trouble.

The present invention, when the busy tone or voice signal from the telephone line is detected when the communication line is set up by the modem with built-in AA type NCU, and when the line is disconnected due to the deterioration of the line condition during communication, the line condition is generated. An object of the present invention is to provide a redial control method for automatically redialing data based on the judgment.

[Means for solving problems]

Means taken by the present invention to solve the above-mentioned problems in the line connection system using the AA type NCU built-in modem will be described with reference to FIG.

FIG. 1 is a block diagram showing the basic configuration of the present invention.

In FIG. 1, 11 is a modem with built-in AA NCU (hereinafter, simply referred to as modem 11), 12 is a terminal interface for connecting with a DTE (not shown), and 13 is for connecting with a switching network (not shown). It is a telephone line that

In the automatic call command sent from the DTE to the modem 11, a redial instruction parameter is added as redial information.

In the modem 11, 111 is an AA type NCU (hereinafter referred to as NCU111), which controls the connection with the switching network and the connection between the DTE and the telephone line.

112 is a signal quality detector (SQD)
Then, a signal quality instruction value (SQ instruction value) for instructing the quality of the received signal during communication is generated.

A tone detection circuit 116 detects a busy tone or a voice signal of the telephone line when the communication line is set.

Reference numeral 113 denotes a redial control unit, which determines the quality of a received signal when the tone detection unit 116 detects a busy tone or a voice signal, and also based on the SQ instruction value input from the SQD 112.
When the deterioration in the quality of the received signal is detected, the line is disconnected and the NCU 111 is instructed to redial based on the redial instruction parameter in the automatic call command.

[Work]

The modem 11 automatically makes a call based on the automatic call command sent from the DTE to establish a line connection with the partner station.

During line connection, if the tone detection circuit 116 detects a busy tone or voice signal that the other party is busy from the line,
The redial control section 11 is sent to the NCU111 based on the redial instruction parameter in the automatic call command after disconnecting the line.
3 instructs redial.

That is, although the communication partner is a modem, there is a case where the communication partner has a configuration in which a modem and a telephone are connected in parallel.
In such a configuration, if the telephone is off-hook for a call from the exchange, the connection with the modem cannot be established.

So the phone goes off-hook and the voice signal is sent back,
If detected by the tone detection circuit 116, the line is disconnected and redial is performed.

When redialing is performed and the remote station is connected again and the call bell rings, the telephone is connected off-hook without going off-hook by knowing that the previous communication was a modem.

As described above, when either the busy tone or the voice signal is detected from the received signal of the partner station when the line is set, the line is disconnected and redial is automatically performed. It can be omitted.

During the data communication with the line connected, the SQD 112 detects the quality of the signal received from the partner station and generates the SQ instruction value.
Now, when the signal quality is good, the level of the SQ instruction value is low, and the signal quality is instructed by the level of the SQ instruction value becoming higher as the signal quality decreases (the SQ instruction value of the present invention. Content is not limited to this).

During data communication, if the line condition deteriorates and the signal quality deteriorates, the level of the SQ instruction value generated by the SQD 112 increases.

The redial control unit 113 determines the quality of the received signal based on the SQ instruction value input from the SQD 112, disconnects the line when deterioration of the received signal quality is detected, and sets the redial instruction parameter in the automatic call command as the redial instruction parameter. Based on this, the NCU111 is instructed to redial.

When the line is connected to the partner station via the exchange network, there are many connection routes for the line connecting to the partner station, and the state of each line is usually different for each line. For example, even if the condition of one line route is bad, the condition of the other line route may be good. Therefore, if the modem 11 redials and reconnects to the same partner station whose line has been disconnected during communication, it is possible to make a connection by the line route in a good state.

As described above, even when the line is disconnected due to the deterioration of the signal quality due to the deterioration of the line status during communication, the modem automatically redials to the same partner station and reconnects the line. It can be done. that time,
It is possible to connect by a circuit route in good condition.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

FIG. 2 is a block diagram of the configuration of an embodiment of the present invention, and FIG. 3 is a processing flowchart of the embodiment.

(A) Configuration of the embodiment In FIG. 2, AA type NCU built-in modem 11 (modem 11), A
The A-type NCU111 (NUC111) is as described in FIG.

Modem 11 is assumed to be a two-wire full-duplex modem in this example.

In addition to redial control, 113 also controls the overall operation of the modem 11 such as setting the operation mode of the modem 11 and controlling the NCU 111.

In the control unit 113, 113a is a microprocessor (MPU)
In accordance with various commands given by DTE, modem 1
The operation mode 1 is set, and the NCU 111 is controlled to perform dialing or the like. A command RAM 113b stores various commands sent from the DTE. 113c is a program ROM
Stores programs for instructing various control operations performed by the modem 11.

A receiving unit 114 demodulates original data from the signal received from the partner station. The SQD 112 is shown inside the receiving unit 114 because it uses the signal obtained during the demodulation operation performed by the receiving unit 114 to generate the SQ instruction value.

A carrier detection circuit (CD detection circuit) 115 detects a carrier in a received signal.

116 is a tone detection circuit, which is a tone on the telephone line, that is,
It detects and determines voice signals, dial tones, ring back tones, and busy tones, and detects and determines the presence or absence of these tones.

A transmitter 117 modulates a carrier with data from the DTE and sends it out over the telephone line.

A band separation circuit 118 separates the transmission signal sent from the transmission unit 117 and the reception signal by band.

12 is a terminal interface, a DTE (not shown) and a modem 1
Connect between 1 RS-232C as terminal interface 12
Is used.

Reference numeral 13 is a telephone line connected to a switching network (not shown).

(B) Operation of Embodiment The operation of the embodiment will be described with reference to the processing flowchart of FIG. 3 and its steps.

Step S _{1 An} automatic call command is sent from the DTE (not shown) to the modem 11 via the terminal interface 12 using the ASCII code.

During this automatic call command, if the line connection fails, the partner station does not come out, the partner station is busy, or the line status after connecting to the partner station, as shown in the example below. If a disconnection is made during communication due to deterioration or the like, a parameter for giving an instruction to automatically redial the same party again is added.

DP0424774111R3 [Example of automatic call command] In this automatic call command, the first "D" indicates a dial command, and the next "P"("T" when using push button dial) is a pulse dial. And instruct "04
24774111 "indicates the other party's telephone number.

The last "R3" is a parameter for instructing redial. Among these, "R3" is a parameter for instructing redial, and "3" indicates that the number of times of automatically redialing is three times. As the parameter for instructing redial, characters or symbols not used for dialed numbers can be used other than "R". In this way, by detecting this parameter, it is possible to know both the end of the telephone number and the presence / absence of redial. Further, the number of redials can be generally n times other than "3". If there is no instruction for the number of redials n, it is treated as once. A code other than ASCII code may be used for the automatic call command.

Upon receiving the automatic call command, the step S ₂ MPU 113a stores this command in the command RAMA 113b and controls the NCU 111 to perform dialing. The NCU111 dials the telephone number "0424774111" in the automatic call command. The telephone number is sent to the telephone line 13 in the form of a pulse signal.

If it fails to dial, the process shifts to a step S _6, performs a redial, if successful to dial, and then proceeds to the next step S _3.

When dialing fails, for example, when dialing an external line using the in-house PBX, the external line is not connected. In this case, the dial tone for the outside line is not returned. MPU113a instructs the detection of external dial tone to tone detection circuit 116, when the external line dial tone is not detected by the tone detection circuit 116 to perform the redial processing proceeds to step S _6. The processing in step S _6, will be described later.

After dialing steps S ₃ , S ₄ , and S ₅ , the MPU 113a instructs the tone detection circuit 116 to detect busy tone (step S ₃ ), detect voice (step S ₄ ) and detect ringback tone. (Step S ₅ ) is performed.

Because if the tone detection circuit 116 detects a busy tone (step S ₃₎ partner is busy, performing the redial processing proceeds to step S _6.

In the case of a modem, a human may respond by mistakenly switching, and in that case, voice is detected by the tone detection circuit 116. Even if the tone detector 116 detects a voice (step S ₄ ), it is considered that the line connection has failed, and the process proceeds to step S ₆ to perform the redial process. Unlike the ringback tone (2100HZ), the voice has a level above a certain threshold and is generated with irregular synchronization that is different from the busy tone and ringback tone.Voice is detected by detecting this. It

Even if the ring back tone is detected but the other party does not come out within the predetermined fixed time (step S ₅ ), it is considered that the line connection has failed, and the process proceeds to step S ₆ to perform the redial process. The MPU 113a counts the duration of the ringback tone sent from the tone detection circuit 116 by an internal timer, and if the ringback tone continues for a certain period of time or more, it is determined that the line connection has failed.

In step S ₂ to S _5, when failing to line connection, MPU 1
13a performs disconnection processing of the line.

Step S _{6 If the} line connection fails, the MPU 113a detects whether or not there is a parameter (Rn) instructing redial in the automatic call command.

If the parameter (Rn) is not detected, the process ends, and if the parameter Rn is detected, the next step
The processing of S _7.

Step S _{7 The} MPU 113a counts the number of redials and determines whether or not it has reached the designated value n. When the designated value is redialed n times, the process is terminated without redialing.

If the number of redials does not reach the specified value n, the process returns to step S ₁ after a predetermined delay time (Delay) and redialing is performed. The delay time is selected at different values depending on the redial by circuit condition deterioration described respective line connection contents of failure and post caused by the step S ₁ to S _5.
These values are given in advance as commands in the command RAM 113b.

In addition, the number of times of automatic redial may be restricted to a certain number or less by law or the like. If the number of redials n indicated by the parameter Rn is larger than the restricted number of times, the number of redials is limited to the restricted number of times. Since the number of regulations often varies from country to country, the number of regulations for each country is stored in the program ROM 113c and processed so that the number of redials is less than or equal to the number of regulations for each country.

If in step S ₈ Step S ₁ to S ₅ line connection was successful, or the line connection by redialing is invalid redial control if done correctly, with the partner station in full duplex normal Data communication is performed.

When transmitting, the data from the DTE is sent to the terminal interface 12
Is input to the transmission unit 117 via. The transmission unit 117 modulates the carrier with this data, and the band separation circuit 118 and the NCU 111.
To the telephone line 13 via. The transmission signal is sent to the partner station via a switching network and a receiving modem not shown.

During reception, the signal received from the partner station is the telephone line 13, NCU1.
The signal is input to the receiving unit 114 and the CD detection circuit 115 via 11 and the band separation circuit 118 (the reception signal is also input to the tone detection circuit 116, but the tone detection circuit 116 does not operate during data communication).

The receiving unit 114 demodulates the original data from the received signal and sends this data to the DTE via the terminal interface 12.

Step _{9 The} SQD 112 generates a signal quality instruction value (SQ instruction value) from the received signal and supplies it to the MPU 113a.

When a QAM (Quadrature Amplitude Modulation) wave is used as a transmission and reception signal, the SQ indication value is a reference point at the time of demodulating the QAM wave (its size is proportional to the maximum value of the reception signal) and a rectangular grid. It is represented by the sum of the distances between the signal points arranged at the points. The larger the sum of the distances, that is, the larger the level of the SQ instruction value, the higher the error occurrence rate and the lower the signal quality. Therefore, this SQ
By monitoring the level of the indicated value, the signal quality and line condition can be detected.

The MPU113a sets a threshold value, and when the level of the SQ instruction value input from the SQD112 exceeds this threshold value, it is determined that the line condition has deteriorated and the signal quality necessary for communication cannot be obtained, and the line is disconnected once. and returns to step S ₆ and performs the redial processing described above.

Step S _{10 Even if the} SQ instruction value is lower than the threshold value and the line condition is good, if the carrier from the partner station is not detected for a certain time or more, the communication is ended.

When data is sent from the partner station, the carrier is always sent by convention, so the carrier is detected by the CD detection circuit 115. If the carrier detection signal is not input from the CD detection circuit 115 for a certain period of time, the MPU 113a determines that the communication from the partner station has ended, and performs communication end processing.

When sending data to the other station from step S ₁₁ DTE, D by convention
An ER (Equipment Ready: data terminal ready) signal is sent from the TE to the modem 11.

The MPU 113a monitors the ER signal sent from the DTE via the terminal interface 12, and when this ER signal is not detected for a certain period of time, determines that the data communication from the DTE has ended, and performs communication end processing. .

Although the embodiment in the case of the full-duplex modem has been described above, the present invention is not limited to the case of the full-duplex modem, but is also applied to the case of the half-duplex modem.

In the case of a half-duplex modem, instead of the band separation circuit 118, the receiving unit 117 is connected to the NUC111 when transmitting and the receiving unit 11 is receiving when receiving.
4. A switching circuit that connects the NCU 111 to the CD detection circuit 115 and the tone detection circuit 116 is used. The other configuration is the same as that of the full-duplex modem, and its circuit connection and redial operation are the same as those of the above-mentioned full-duplex modem.

〔The invention's effect〕

As described above, according to the present invention, the line is disconnected when a voice signal or a busy tone is detected from the telephone line when the communication line is set up, or when the signal quality is deteriorated due to the deterioration of the line state during communication. In the case of the call, the modem can automatically redial the same station and reconnect the line. At that time, since redialing is automatically performed, it is possible to save the trouble of re-setting, and it is possible to connect by the line route in a good state.

[Brief description of drawings]

FIG. 1 ... Explanatory diagram of basic configuration of the present invention, FIG. 2 ... Explanatory diagram of configuration of an embodiment of the present invention, FIG. 3 ... Processing flowchart of the same embodiment, FIG. 4 ... Conventional data terminal device ( Fig. 1 and Fig. 2 are diagrams for explaining the line configuration of the DTE) and the modem. In Fig. 1 and Fig. 2, 11 ... Modem with a built-in outgoing / incoming automatic network controller (AA NCU), 12 ... Terminal interface, 13 ... 111
...... Calling and receiving automatic network controller (AA type NCU: NCU), 1
12 …… Signal quality detection circuit (SQD), 113 …… Redial control section (or control section).

Claims (1)

[Claims] 1. A redial control system using a modem (11) with a built-in outgoing / incoming automatic network controller (111), (a) outputting a quality value of a received signal received by the modem (11) during communication. A signal quality detection circuit (112), (b) a tone detection circuit (116) for detecting a busy tone and a voice signal of a telephone line received by the model (11) when the communication circuit is set, (c) the signal quality When the quality value output from the detection means (112) drops below a certain value, or when the tone detection circuit (116) detects a busy tone or a voice signal, the set line is disconnected. And a redial control unit (113) for instructing the automatic dialing / incoming network control device (111) to perform redial based on a redial instruction parameter in an automatic call command. Dial control system.