JPH089461A - Data transmission system - Google Patents

Abstract

PURPOSE:To shorten the time required for establishing a communication protocol. CONSTITUTION:When a call is originated for transferring data from a personal DTE 1 to a terminal DTE 2 of a fixed network, a call originating request and analog MODEM function setting information are transmitted from the DTE 1 to an adapter ADP 30, and the ADP 30 extracts the MODEM function setting information and a correspondent pattern number from a memory 34 and transmits them from a mobile radio equipment MS through a digital network DL to an adapter 50 of an exchange while putting them on call setting information. At the adapter ADP 50, the MODEM function setting information corresponding to the received pattern number is read from a memory 54 and set to an analog MODEM 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system for transmitting facsimile data, personal computer data and the like through a digital transmission line having a transmission speed slower than an analog voice transmission line such as a digital mobile communication line.

[0002]

2. Description of the Related Art Conventionally, G3 facsimiles and MNs have been used.
Between analog data modems of terminals such as P modem,
In a system for performing data transmission by connecting via a digital line network, since the digital line network does not have a means for distinguishing between an analog data signal and a voice signal, an analog data modem generally has a P signal of a voice signal in a 3 kHz band.
Data transmission is performed by allocating a 64 kbps digital line capable of transmitting CM signals. That is, the analog data signal is transmitted by imitating the voice signal. However, the transmission speed of an analog data modem is generally about 2.4 to 9.6 kbps, and transmitting such a low speed data signal using the 64 kbps digital line is wasteful in terms of transmission efficiency. Not preferable.

Therefore, conventionally, a data relay system has been proposed in which a data signal of an analog data modem is transmitted using a digital line having a speed equal to the transmission speed of the analog data signal. For example, in the system disclosed in Japanese Patent Application No. 4-245128, even if there is a deviation between the transmission speed of the analog data modem and the digital transmission line, the bit slip phenomenon does not occur, whereby the analog data signal is transmitted. Data can be transmitted reliably without data loss, and wasteful data transmission is performed even if the timing when the communication protocol is established and the data can be transferred differs between the calling side and the called side. It has been proposed that a data transmission system that can prevent data loss and improve the data transmission efficiency.

FIG. 4 shows the system shown in Japanese Patent Application No. 4-245128. In the figure, two terminal devices DTE1 and DTE2 that oppose each other are connected via a digital circuit network DL including a wireless transmission path for mobile communication. The terminal devices DTE1 and DTE2 are, for example, personal computers, and these terminal devices DTE1.
Analog data modems MOD10 and MOD20, which are MNP modems, are attached to 1 and DTE2. On the other hand, an adapter device ADP1 is provided on the digital network DL side.
0 and ADP20 are provided, and the analog lines S are provided to these adapter devices ADP10 and ADP20, respectively.
Analog data modem MOD1 via L1 and analog line network (fixed communication network, hereinafter referred to as analog line) SL2
0, MOD 20 is connected. Adapter device ADP
20 is usually provided in the exchange.

The adapter devices ADP10 and ADP20 are
Analog data modems 11 and 21, protocol monitoring units 13 and 23, stuff synchronizing units 14 and 24,
The frame synchronization control units 15 and 25 are provided. The analog data modems 11 and 21 are MNP modems, and the analog data modems MOD10 and MOD10 on the terminal device side, respectively.
A function of demodulating the transmitted analog data coming from the MOD 20 via the analog lines SL1 and SL2 into digital data, and modulating the received digital data coming from the digital line network DL into analog data and sending it to the analog lines SL1 and SL2, respectively. have. The protocol monitoring units 13 and 23 perform control for connecting the analog data modems MOD10 and MOD20 on the terminal device side to each other via the digital network DL according to a predetermined communication protocol.

The stuff synchronization control units 14 and 24 are provided for the transmission speed of the transmission digital data demodulated by the analog data modems 11 and 21 and the digital line network DL, respectively.
Bit-slip information (information indicating whether or not a bit-slip has occurred) is generated from the transmission speed difference. At the same time, it instructs the analog data modems 11 and 21 about the clock speed of the analog data signals to be sent to the analog lines SL1 and SL2, based on the bit slip information extracted by the frame synchronization control units 15 and 25, respectively.

The frame synchronization control sections 15 and 25 add bit slip information and a frame synchronization signal to the transmission digital data transferred from the stuff synchronization control sections 14 and 24, respectively, to form a data frame, and the data frame is digitally transmitted. It is sent to the line network DL. Further, the frame synchronization control units 15 and 25 receive the data frames arriving via the digital network DL in frame synchronization, respectively, and decompose the received data frames to extract the bit slip information. Then, the received digital data signals corresponding to the number of bits designated by the bit slip information are transferred to the stuff synchronization control unit 14.

By the way, in the past, the transmission of digital data of a personal computer and digital data of a facsimile has been carried out through a general public fixed telephone network. For this reason, as described above, these digital data are converted into analog data in the voice band by the analog data modem and transmitted, and the personal computer is connected to the analog data modem so as to enable such transmission. Is provided with a connector of a predetermined shape, and similarly, in a G3 facsimile, an analog data modem is built in, digital data is converted into analog data and output, and for connecting this to an analog line, In other words, it had a connector structure for connecting an analog data modem.

Therefore, when transmitting / receiving the digital data of the terminal devices DTE1 and DTE2 of the personal computer through the digital line network DL such as the mobile communication network, it is already provided like the conventional transmission through the public telephone fixed network. The analog data modems MOD10 and MOD20 are connected through the provided analog transmission connector port to convert the digital data into analog data and take it out. In order to be able to transmit, the analog data from the analog data modems MOD10 and MOD20 is reproduced by the adapter devices ADP10 and ADP20 to the original low speed digital data such as 2.4 to 9.6 kbps. In this case, since the reproduced digital data has variations in the data rate (frequency), it is converted into data of a constant rate regardless of the data rate, that is, stuff synchronization is performed to the digital transmission network DL. I was sending it out. In mobile communication, the digital line network DL side of the adapter device ADP10 is connected to the digital line network DL via a mobile radio MS such as a mobile phone, and the digital line network DL side of the adapter device ADP20 is a radio base station. It is connected to the digital circuit network DL via the BS. Also, the mobile radio MS forms the digital signal received from the adapter device ADP10 into a digital radio signal frame for mobile communication, transmits and receives a signal on the digital radio line to and from the radio base station BS, and transmits the digital radio signal frame. Performs transmission / reception synchronization control. The radio base station BS demodulates the digital radio signal frame received from the mobile radio MS into a digital signal and transmits the digital signal to the adapter device ADP20 and at the same time the adapter device ADP.
The digital signal from 20 is formed into a digital radio signal frame for mobile communication and transmitted to the mobile radio MS.

As described above, the digital data is converted into analog data by the analog data modem, converted into digital data by the adapter device, and then converted into the digital line network D.
The operation sequence from call origination to data transmission in the data transmission system shown in Japanese Patent Application No. 4-245128 for transmitting L is performed as shown in FIG. It is assumed that the terminal device DTE1 originates a call to transmit a data signal to the terminal device DTE2. Then, a call request is sent from the MNP modem MOD10 on the terminal device DTE1 side to the adapter device ADP10, and the MNP modem MOD2 on the partner side is sent from the adapter device ADP10.
An incoming call signal 41 is sent to 0 through the digital network DL. The respective incoming call timings R and R'in the adapter device ADP10 on the calling side and the adapter device ADP20 on the called side are shown.

When the above-mentioned call request is sent, between the calling adapter device ADP10 and the MNP modem MOD10,
When an incoming call signal is sent, the adapter device AD on the incoming call side
Control for establishing the MNP communication protocol is independently performed between the P20 and the MNP modem MOD20. That is, the calling side ADP 10 and M
With respect to OD10, from ADP10 which received the call request to MOD10, high-group carrier 42 of V.22bis modem
After being sent, from MOD10 to ADP10 V. 22
The low group carrier 43 of the bis modem is returned. Then, the physical connection handshake 44 of the V.22bis modem is performed between the ADP 10 and the MOD 10. When the physical connection handshake 44 ends, the LR signal 45 is transmitted and received between the MOD 10 and the ADP 10. Subsequently, the LA signal 46 containing no parameter is sent from the MOD 10 to the ADP 10, while the ADP 10 sends the LA signal 46 to the MDP.
The LA signal including the parameters is returned to the OD 10.
This LA signal 47 is repeatedly transmitted.

On the other hand, between the ADP 20 and the MOD 20 on the called side, the MOD 20 and the ADP 20 receive the incoming signal.
After the high group carrier 42 of the V.22bis modem is sent to the MOD 20, the low group carrier 43 of the V.22bis modem is sent back to the MOD 20. And ADP2
0 and the MOD 20 a V.22bis modem physical connection handshake 44 is performed. When this physical connection handshake 44 ends, the AD of the calling side described above
Similar to between P10 and MOD10, MOD20 and ADP2
LR signal 45 is sent and received between 0 and MOD.
20 to ADP 20 LA signal without parameters 4
6 is transmitted, and subsequently, the LA signal 47 including the parameters is repeatedly transmitted from the ADP 20 to the MOD 20.

In this way, the adapter device AD on the calling side
The MNP communication protocol is established between the P10 and the MNP modem 10 and between the called adapter device ADP20 and the MNP modem MOD20, and a signal to that effect is transmitted via the intra-network signal 48 of the digital circuit network DL. It is assumed that the notification is sent to the respective adapter devices ADP20 and ADP10. Then, the adapter device AD that has received the communication protocol establishment notification by the intra-network signal 48.
The P20 and ADP10 respectively stop the transmission of the LA signal 47, and instead send the LA signal 50 including the information indicating that the communication protocol has been established, to the MNP modems MOD20 and MOD1.
Transfer to 0 respectively. Then, the adapter device ADP2
0, ADP10 completes the intervention in the phase for establishing the communication protocol between the modems MOD20, MOD10, and thereafter starts the data transfer relay process. On the other hand, the modems MOD20 and MOD10 are connected to the adapter device ADP2.
0, when the LA signal 50 is received from the ADP 10, the transmission of the data which has been waiting until then is started.

That is, the adapter devices ADP20, AD
P10 is not limited to the period until the communication protocol is established with the modems MOD20 and MOD10, respectively, and also during the transition period after the communication protocol on the self side is established, the adapter device ADP20, A
Until the notification indicating that the communication protocol is established by the intra-network signal 48 from the DP 10 is received, the modem MOD
20, a signal for suppressing the start of data transmission is transmitted to the MOD 10.

[0015]

However, the conventional system as described above has various problems to be improved as follows. That is, in the above system, the calling party M
By sending a call request from the NP modem MOD10 to the adapter device ADP10, the MOD1 is transmitted from the ADP10.
The high-group carrier 42 of the V.22bis modem is sent to 0 and the negotiation of the MNP communication protocol is started, but the call request is usually triggered by an off-hook signal from the MOD 10 To be judged. However, similarly, when the MOD 20 on the called side receives the incoming call signal, it sends an off-hook signal to the adapter device ADP20 on the called side, and then the high group carrier 42 of the V.22bis modem is transmitted from the MOD 20 to the ADP 20. Sent MN
The negotiation of the P communication protocol is started. A
Since the DP 20 does not always operate at the timing of receiving the incoming call signal from the ADP 10,
The off-hook signal sent from the MOD 20 serves as a trigger for starting the operation.

As described above, the adapter device cannot determine whether its own operation is the calling side operation or the called side operation at the time of receiving the off-hook signal. , V. 22bi
It is necessary to start the high-group carrier detection operation of the s-modem, perform the call-side operation when the carrier is detected within a certain time, and perform the call-side operation when the carrier is not detected. The time for detecting the high-group carrier of this V.22bis modem is, for example, RCR-STD27B "4.
V. 42 ANNEX modem communication procedure In the timer 2 "of Fig. 4.2.1, it is set to 10 seconds. Further, it takes about 5 seconds according to the ITU recommendation from the transmission of the answer tone of 2100 Hz to the end of the physical connection handshake 44 which is actually performed prior to the transmission of the high-group carrier of the V.22bis modem. LR performed after physical connection
It takes about 1 second to send and receive the signal 45 and the LA signal 46. The intra-network signal 48 for notifying the establishment of the MNP protocol from the ADP 10 on the calling side is the ADP 20 on the called side.
It takes about 16 seconds in total to be sent to.

Further, in the conventional system, when the LA signal 46 is sent from the MOD 10, the ADP 10, MO
Since the communication protocol between D10 is established, MOD10
Although the connection completion display is sent to the DTE 1 and the DTE 1 is notified that the data transmission is possible, in reality, the intra-network signal 4 transmitted from the ADP 20 is transmitted.
8 is received by ADP10, ADP20, MOD2
There is a problem that the MOD 10 cannot transmit the analog data signal until the MOD 10 receives the LA signal 50 including the information that the communication protocol between 0s has been established. Therefore, although the terminal device DTE1 apparently starts transmitting data from the terminal device DTE1,
2 caused the phenomenon that data did not reach easily and hindered smooth data transmission between terminals.

On the other hand, in the data transfer and relay processing after the establishment of the communication protocol, the communication speed of the digital line network, which is represented by the wireless transmission line for mobile communication, and the communication speed of the analog data modem are almost the same. In the case of such a line, since redundant information for error detection and correction cannot be added sufficiently when sending digital data to the digital line network, a transmission error that cannot be error-corrected occurs in the digital line network. In that case, as a result, data is retransmitted frequently between the analog data modems, and the transmission efficiency decreases. Since the communication protocol of the analog data modem is originally designed assuming connection to a wired communication network with relatively few transmission errors, the transmission efficiency when applied to the digital line network where the above transmission errors occur frequently. Is significantly reduced.

An object of the present invention is to provide a data transmission system capable of shortening the time required to establish a communication protocol from the origination / termination call to the actual start of communication, thereby improving the data transmission efficiency. is there.

[0020]

According to the present invention, a first terminal device for transmitting / receiving digital data is connected to an analog transmission line via a first analog data modem, and the analog transmission line is analog-digital. Connected to a digital transmission line via a first adapter device for mutual conversion,
In a data transmission system in which a second terminal device for sending / receiving digital data is connected to the digital transmission line via a second adapter device, the first adapter device receives the analog data coming from the analog transmission line. A second analog that is demodulated, reproduces digital data according to the communication protocol of the analog data modem, modulates the received and reproduced digital data into analog data according to the communication protocol of the first analog data modem, and sends the analog data to the analog transmission path. A data modem and the reproduced digital data are converted into digital signals according to a communication protocol dedicated to the digital transmission line, and the received digital signals from the digital transmission line are reproduced into digital data according to the communication program dedicated to the digital transmission line. Shi And for digital line communication protocol control means for supplying to said second analog data modem,
Frame synchronization control means for transmitting the converted digital signal to the digital transmission path, receiving the digital signal from the digital transmission path and supplying it to the communication protocol control means; the second terminal device; Based on the first setting information pattern memory storing the combination of analog modem function setting information required for one adapter device and the pattern information indicating the combination, and the pattern information sent from the second adapter device, The second data relay transmission device comprises means for reading out the first setting information pattern memory and setting the function of the second analog data modem in response to the first setting information pattern memory, wherein the second data relay transmission device is connected to the second terminal device. The terminating means and the digital data transmitted from the first terminal device via the terminal terminating means are converted into the digital data. The digital signal is converted into a digital signal according to the communication protocol dedicated to the transmission line, the digital signal received from the digital transmission line is reproduced as digital data according to the communication protocol dedicated to the digital transmission line, and the first signal is transmitted via the terminal connection terminating means. Second digital line communication protocol control means for transmitting to the terminal device, the converted digital signal for transmission to the digital transmission line, and the digital signal for arrival via the digital transmission line for receiving the second digital line. Second synchronization control means to be supplied to the communication protocol control means for use, a second setting information pattern memory having the same contents as the first setting information pattern memory, and analog modem function setting information in the signal from the second terminal device. The pattern information corresponding to this is analyzed and the second setting information pattern is analyzed. Obtained from Nmemori, the more the means for transmitting to said first adapter device.

[0021]

FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. 4 are designated by the same reference numerals. In the present invention, adapter devices ADP30 and ADP50 are provided instead of the adapter devices ADP10 and ADP20, respectively. The terminal device DTE1 is connected to the adapter device ADP30 via the interface line IL. Adapter device ADP3
0 includes a terminal connection termination unit 31, a digital line communication protocol control unit 32, a frame synchronization control unit 33, and a setting information pattern memory 34. The terminal connection terminating unit 31 has a function of transmitting and receiving a digital data signal with the terminal device DTE1 and converting a data signal format between the terminal device DTE1 and the communication protocol control unit 32 for digital line. In the digital line communication protocol control unit 32, the terminal device DT
After the analog modem function setting information in the digital data signal from E1 is analyzed, the setting information is retrieved from the prepared setting information pattern memory 34 and converted into a digital signal according to the communication protocol for the digital line. Assembling, notifying a digital signal according to the communication protocol for the digital line to the adapter device ADP50 through the digital transmission line DL, and receiving the digital signal arriving through the digital transmission line DL, the communication for the digital line is performed. The digital data signal is reproduced according to the protocol and is transmitted to the terminal device DTE1 via the terminal connection termination unit 31. The frame synchronization control unit 33 adds a frame synchronization signal to the transmission digital signal transferred from the digital line communication protocol control unit 32 and sends it to the digital line network DL, and at the same time, the digital signal arrived via the digital line network DL. Is received in synchronism, and the received digital signal excluding the frame synchronization signal is transferred to the digital line communication protocol control unit 32.

On the other hand, the adapter device ADP 50 includes an analog data modem 51, a digital line communication protocol control unit 52, a frame synchronization control unit 53, and a setting information pattern memory 54. The analog data modem 51 is composed of an MNP modem, demodulates a transmission analog data signal coming from the analog data modem MOD20 on the terminal device side via the analog line SL2 into a digital data signal, and causes the digital line communication protocol control unit 52 to perform the demodulation. It has a function of modulating the reproduced digital data signal into an analog data signal and sending it to the analog line SL2. The digital line communication protocol control unit 52 modulates a digital signal arriving via the digital transmission line DL into a digital data signal according to the communication protocol for the digital transmission line, and sends the digital data signal to the analog data modem 51 and from the analog data modem 51. Control for modulating the received digital data signal into a digital signal and transmitting it to the digital transmission line DL through the frame synchronization control unit 53 and the adapter device AD
Digital circuit network DL between P30 and ADP50
Control for connecting with a digital signal via.
It also has a function of sending the pattern information (number) sent from the setting information pattern memory 34 of the adapter device ADP30 to the setting information pattern memory 54 of the adapter device ADP50. In the frame synchronization control unit 53,
A frame synchronization signal is added to the transmission digital signal transferred from the digital line communication protocol control unit 52 to be sent to the digital line network DL, and the digital signal arriving via the digital line network DL is received in synchronization. , And transfers the received digital signal excluding the frame synchronization signal to the digital line communication protocol control unit 52. The setting information pattern memory 55 receives pattern information (number) from the digital line communication protocol control unit 52.
Is received, analog modem function setting information is retrieved from the pattern information, and the information is sent to the analog data modem 51 through the digital line communication protocol control unit 52 to set the parameters of the MNP modem.

In the setting information pattern memories 34 and 54, for example, as shown in FIG. 2, each combination of the functions to be set in the analog data modem 51 is numbered and stored according to the data transmitted from the terminal device DTE1. . Next, the operation of the system configured as described above will be described with reference to FIG. Now, assuming that the terminal device DTE1 is the terminal device DT
It is assumed that a call is made to transfer a digital data signal to E2. Then, the analog modem function setting information and the call request are sent to the adapter device ADP30 on the terminal device DTE1 side, and the adapter device ADP30 uses the analog modem function setting information to generate the corresponding pattern information (number) from the setting information pattern memory 34. ) Take out. Then, this pattern information is transferred to the adapter device ADP30.
From the adapter device 50 to the adapter device 50, an incoming call signal (call setting information) 56 is sent. When the exchange set with the adapter device 50 that has received the call setting information 56 determines that the call setting information is for data communication, the adapter device 5 in the exchange device 5
At the same time as capturing 0 and providing a digital line network DL between it and the adapter device 30, pattern information (number) of parameter setting information is extracted from the call setting information and sent to the adapter device 50. The transmitted pattern number is decoded by the setting information pattern memory 54 to take out the analog modem function setting information, and the analog data modem 51 is set with the information,
When the setting is completed, analog data modem MOD20
A call is made to the terminal device DTE2 via. That is, an incoming call signal indicating that there is an incoming call is sent to the terminal device DTE2. Calling side terminal device DTE1, Calling side terminal device DTE2
The incoming call timing in R is shown as R, R '.

Since the adapter device ADP 30 on the calling side does not need to call the MNP protocol for the analog data modem, it immediately sends a notification indicating that the communication protocol has been established by the intra-network signal 48. The terminal device DTE2, which receives the call (incoming signal) via the analog data modem MOD20, sets the analog modem function with the analog data modem MOD20 and establishes the physical connection with the analog data modem 51 of the adapter device 50. To do.

That is, the called adapter device ADP50
Between the analog data modem MOD20 and the analog data modem MOD20, the AD received from the modem MOD20 receiving the call in the same manner as shown in FIG.
After the high group carrier 42 of the V.22bis modem is sent to the P50, the V.22bi is sent from the ADP50 to the MOD20.
The lower group carrier 43 of the s-modem is returned. And A
A physical connection handshake 44 of the V.22bis modem is performed between the DP 50 and the MOD 20. When this physical connection handshake 44 is completed, MOD 20 and AD
The LR signal 45 is transmitted / received to / from the P50, the data link is established between the analog data modem MOD20 and the analog data modem 51, and when completed, at this time, the calling side adapter device ADP30 transmits the intra-network signal 48. Is received, the LA signal 50 including the information indicating that the communication protocol is established is transmitted from the adapter device ADP50 to the analog data modem MOD20, and at the same time, the intra-network signal 48 is transmitted to the adapter device ADP30 to change the communication protocol. Notify that it has been established. The adapter device ADP30 receiving this notification transmits the connection completion display 51 to the terminal device DTE1. After that, the adapter device ADP3
0, the ADP 50 shifts to the data transfer mode 49 using the communication protocol for the analog data modem.

The communication protocol dedicated to digital transmission is
It realizes highly efficient error-free transmission. For example, W
ORM-ARQ (The Institute of Electronics, Information and Communication Engineers, June 1991 2
6th CS91-26, RCS91-16 “WORM-A
As shown in "Digital mobile communication G3 facsimile transmission using RQ"), transmission is normally performed up to N (the number of blocks) even if there is no response, and only the block of the number for which a retransmission request is made is selectively performed. It is operated by SR (Selective Retransmission) type ARQ (Automatic Retransmission Request Method), but when the range of unconfirmed blocks exceeds a predetermined number, all N blocks from the oldest unconfirmed block are retransmitted in order, and the oldest unconfirmed block is retransmitted. This GBN (collective response) type A is repeated until N consecutive transmissions are received until the reception response for the block is received.
Operate with RQ. In other words, the SR type ARQ is usually used, but errors occur continuously like burst errors,
When an error frequently occurs, the SR type and the GBN type are adaptively switched according to the transmission state such as switching to the GBN type ARQ.

In the above, the terminal devices DTE1, DTE
Although a personal computer is taken as an example of 2, a device for transmitting and / or receiving other digital signals, that is, transmitting / receiving, may be used. In the case of G3 facsimile, the analog data modems MOD10, MOD20 are usually the terminal devices DTE1, It is built into DTE2.

[0028]

According to the present invention, since the adapter device ADP30 of the communication protocol dedicated to digital transmission is interposed between the terminal device DTE1 and the digital line network DL, and the analog data modem is not interposed, the terminal device DTE1 is provided. Can be transmitted immediately without the need for MNP protocol establishment. An adapter device ADP50 interposed between the digital line network DL and the analog line network SL2
Since the terminal device side follows the communication protocol of the analog data modem and the digital line network side follows the communication protocol dedicated to digital transmission, the communication speed of the digital transmission line represented by the wireless transmission line for mobile communication is SR type ARQ and GBN type AR are used even in a low speed line which is almost the same as the communication speed of an analog data modem and even when errors occur relatively frequently in the digital line network.
Since Q and Q are adaptively switched according to the state of the transmission path, it is possible to suppress a significant decrease in data transmission efficiency.

Further, according to the present invention, the analog modem function setting information between the mobile station MS side terminal DTE1 and the radio base station BS side adapter device 50 is previously stored in the adapter device A.
By patterning the DP 30 side and the ADP 50 side, it is not necessary to send all the analog modem function setting information using a digital signal on the wireless line, and only the pattern number needs to be sent and received. And the holding time of lines other than communication can be shortened, and the use efficiency of wireless lines can be improved.
In other words, each one of the analog modem function setting information,
For example, by the AT command, the conventional digital network DL
Although it takes a considerable time to send the data to the adapter device 50 via the cable, the present invention can significantly reduce this time.

Further, the connector for connecting to the analog data modem provided in the terminal device DTE1 can be used as it is for connection to the adapter device ADP30, and the adapter device ADP30 can be connected to the conventional adapter device ADP10. And a connection port to the digital line network DL, for example, a connection port of a mobile phone, can be connected in the same configuration as the conventional one, and it is not necessary to provide a new connector.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

2 is a diagram showing an example of stored contents of setting information pattern memories 34 and 54 in FIG.

FIG. 3 is a diagram showing an operation sequence of an embodiment of the present invention.

FIG. 4 is a diagram showing a conventional data transmission system.

5 is a diagram showing an operation sequence of the system of FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Daisuke Akiyama 2-10-1 Toranomon, Minato-ku, Tokyo NTT Mobile Communication Network Co., Ltd.

Claims (1)

[Claims] 1. A first terminal device for transmitting / receiving digital data is connected to an analog transmission line via a first analog data modem, and the analog transmission line is via a first adapter device for analog-digital mutual conversion. In a data transmission system in which a second terminal device for transmitting / receiving digital data is connected to the digital transmission line via a second adapter device, wherein the first adapter device is the analog device. Demodulate analog data coming from the transmission line, reproduce digital data according to the communication protocol of the analog data modem, and modulate digital data received and reproduced from the digital transmission line into analog data according to the communication protocol of the analog data modem. And then sends it to the analog transmission line Data modem and the reproduced digital data is converted into a digital signal according to the communication protocol dedicated to the digital transmission line, and the received digital signal from the digital transmission line is converted into digital data according to the communication program dedicated to the digital transmission line. Communication protocol control means for digital line for reproducing and supplying to the second analog data modem, transmitting the converted digital signal to the digital transmission line, receiving the digital signal from the digital transmission line, and performing the communication. A frame synchronization control means to be supplied to the protocol control means, a combination of analog modem function setting information required between the second terminal device and the first adapter device, and pattern information indicating the combination are stored. 1 setting information pattern memory; The first setting information pattern memory based on the pattern information sent from the adapter device, and setting the function of the second analog data modem in response thereto, the second adapter device comprising: The terminal connection terminating means connected to the two terminal devices, and the digital data transmitted from the second terminal device via the terminal terminating means are converted into digital signals according to the communication protocol dedicated to the digital transmission line, and the digital signals are converted into digital signals. Second digital line communication protocol control means for reproducing digital data received from the transmission line according to the communication protocol dedicated to the digital transmission line and transmitting the digital data to the second terminal device through the terminal connection terminating means. Transmitting the converted digital signal to the digital transmission line, The second frame synchronization control means for receiving the digital signal arriving via the digital transmission line and supplying it to the communication protocol control means for the second digital line, and the second setting having the same contents as the first setting information pattern memory. The information pattern memory and the analog modem function setting information in the signal from the second terminal device are analyzed, and the pattern information corresponding thereto is obtained from the second setting information pattern memory and transmitted to the first adapter device. A data transmission system comprising: