JP3464011B2 - Terminal adapter capable of automatic line / packet switching - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal adapter (TA) for connecting a data terminal (DTE) or the like to a line, and particularly to an existing interface (V.24 / 28, X.
ISDN (Integrated
Services Digital Network) for connecting to a terminal adapter.

[0002]

2. Description of the Related Art In the process of popularization of ISDN, the use of ISDN using existing telephones and data terminals is the main focus. The terminal adapter is a device for connecting an existing terminal to the ISDN without changing the current information communication system form of the user. Therefore, the advantages of ISDN such as high speed and economy can be easily provided.

FIG. 10 shows a conventional terminal adapter (T
FIG. 4 is a sequence diagram showing an example of a communication procedure for performing data communication between the data terminal (DTE) 30 and the network (ISDN) via A) 32. 10, a space between the terminal 30 and the terminal adapter 32 is V.V. which is normally used in personal computers and the like. 24/28 interface (corresponding to RS-232C interface) or the like. Also, the terminal 3
0 is V.0 in the synchronous terminal. 25 bis command, an asynchronous terminal uses an AT command or the like to make a call request to the terminal adapter 32 by terminal operation. At that time, the contents of the dial command before the data communication start by the user himself,
Alternatively, the circuit switching or packet switching is selectively designated by the mode setting of the terminal adapter 32.

Next, the terminal adapter 32 uses the call setting message (SET of Q931) having the line designating parameter (line switching or packet switching), the destination address, etc.
UP) to the network 31. After that, the network 31 sends to the terminal adapter 32 a call setting acceptance message indicating acceptance confirmation of the call setting message, and finally a response message notifying that the destination terminal responds and the communication path is set. When the terminal adapter 32 receives the response message, the terminal 3
A response signal is sent to 0 to instruct the start of data transmission.
Upon receiving the response signal, the terminal 30 starts data transmission to the network 31 via the terminal adapter 32.

[0005]

By the way, the charge mode is different between the circuit switching and the packet switching, and the charge is determined according to time in the circuit switching and according to the data amount in the packet switching. The minimum usage fee for circuit switching is 10 yen, while that for packet switching is 0.4 yen. The communication fee is further subdivided by various communication parameters such as communication distance and day / night and distinction between weekdays and holidays.

Therefore, the line fee for data communication differs depending on whether line switching or packet switching is used even when the same amount of data is sent, and how the above various fee parameters are selected at that time. become. Today, with the advent of various communication networks, such as corporate networks, VANs, LANs, etc., that connect a wide range of regions, the amount of data handled there has been increasing dramatically, and the reduction of communication costs for users has hitherto been achieved. It is of even greater concern.

However, as described above, in the prior art, when performing data communication, the user preliminarily determines the contents of the dial command and the mode of the terminal adapter by his / her own judgment, and selects what is called manual circuit switching or packet switching. Therefore, it is difficult for the user to grasp the communication data amount in advance and to use the cheaper line efficiently by considering the above various parameters. However, there was a problem that the reduction of the above could not be achieved sufficiently.

In view of the above problems, an object of the present invention is to enable an existing data terminal to efficiently use an ISDN network capable of circuit-switched and packet-switched communication at a low charge. An object of the present invention is to provide a terminal adapter that automatically selects circuit switching or packet switching to achieve reduction in communication cost.

[0009]

According to the present invention , a terminal is connected to a network.
The terminal adapter that connects to the network line is a terminal
Connection procedure with a network line
Pseudo-line communication control means to execute, and sent from the terminal
Communication end detection means for detecting the end of incoming data, and
Terminal data storage means for temporarily storing data
The various parameters are based on the amount of data stored in the data storage means.
Data by calculating or comparing data
Select the circuit or packet switch with the cheaper transmission fee
Exchange type determining means and the exchange type after the end of the data.
Circuit switching or packet exchange selected by another determination means
Pseudo terminal connection communication procedure for exchange network
Execute and send the data stored in the terminal data storage means
And pseudo terminal communication control means .

Further, according to the present invention, the exchange type judging means 7 has the transmission data amount (transmission amount and packet size), the destination telephone number (distance) and / or date and time (day, night, weekday, etc.) as the parameters. Holidays) and has a billing table for determining the line usage fee, and the communication end detecting means 5 detects the end of the transmission data by a no-signal state which continues for a predetermined time during data transmission, And / or transmission data end signal detecting means for detecting with a control signal for instructing the end of the transmission data.

[0011]

The pseudo line communication control means 4 has a pseudo line communication control function for performing communication control (see FIG. 10) equivalent to that for connecting and communicating with the line to the terminal 1. Then, the transmission data from the terminal 1 is temporarily stored in the terminal data storage means 6 by the function. When the end of transmission data from the terminal 1 is detected by the communication end detecting means 5, the exchange type judging means 7 compares and considers the amount of received data in the terminal data storage means 6 and the various charge parameters at that time. Select the exchange type (line / packet) with the lowest charge.

Next, the pseudo terminal communication control means 9 acts as a pseudo terminal instead of the terminal 1 to execute communication control of the terminal with the network and send data to the selected switching network. The device control means 10 includes the above-mentioned means (4,
The present invention is realized as an entire adapter device by managing each control sequence of 5, 7, 9). The terminal interface means 3 is an existing data terminal interface,
For example, electrical connection with various V and X series terminals and communication procedures are executed. The line interface means 8
Is a DSU (Digital
Interface to connect with the Service Unit). In addition, the line interface means 8 uses the D
The interface may be directly interfaced with the ISDN line by also using the function of SU.

[0013]

EXAMPLE FIG . 1 shows the basic configuration of a terminal adapter.
It is a figure. As shown in Fig. 1, the terminal adapter
The data transmission unit interfaces the signal from the terminal 1.
For the terminal interface means 3 for said terminal 1
Pseudo line communication that executes connection communication procedure with the line in a pseudo manner
Control means 4, end of data sent from the terminal 1
Communication end detecting means 5 for detecting
Terminal data storage means for temporarily storing incoming data
6, the amount of data stored in the terminal data storage means 6
Calculate or compare various charge parameters based on
By doing so, the circuit exchange for the one with the lowest data transmission fee
Alternatively, the exchange type determination means 7 for selecting packet exchange, the network
A line interface for interfacing with the network side
Selected by the exchange means 8 and the exchange type determination means 7.
Pseudo for circuit switched or packet switched networks
Execute the connection communication procedure of the terminal to the above-mentioned line interface
Stored in the terminal data storage means 6 via the means 8
Pseudo terminal communication control means 9 for transmitting data, and
For controlling each means 4, 5, 7, 9 as a whole device
Automatic circuit / packet switching composed of device control means 10
A switchable terminal adapter is provided. Figure 2
1 is a block diagram showing an embodiment of a terminal adapter according to the present invention. 2 and FIG. 1, the terminal control unit 21 and the ISDN line control unit 26 of FIG. 2 correspond to the terminal interface unit 3 and the line interface unit 8 of FIG. 1, respectively. The terminal control unit 21 and I of FIG.
The SDN line control unit 26 is the pseudo line communication control means 4 of FIG.
Also, it may have a part or all of the respective functions of the pseudo terminal communication control means 9. Further, the timer 27 of FIG. 2 corresponds to the communication end detecting means 5 of FIG. 1, and the calculation circuit 2 of FIG.
8 and the charging table 29 correspond to the exchange type determining means 7 of FIG. CPU 24, ROM 22 and RAM in FIG.
Reference numeral 23 corresponds to the device control means 10 of FIG.
U24, ROM22 and RAM23 so-called CPU
The circuit has the functions of the pseudo line communication control means 4 and the pseudo terminal communication control means 9 of FIG. 1, and further the exchange type determination means 7 of FIG.
The function of may be included. The RAM 23 in FIG. 2 also corresponds to the terminal data storage means 6 in FIG.

2, the terminal control unit 21 of the terminal adapter 20 according to the present invention is an interface (V.24) for electrical and communication procedures to an existing data terminal.
/ 28, V.I. 25 bis, X21, etc.). CP
The U circuits 24, 22 and 23 control the terminal adapter 20 as a whole, and the RAM 23 functions as a data buffer for temporarily storing the data sent from the terminal. As described above, the CPU
The circuit may perform some or all of the functions of the terminal control unit 21 such as the control of the communication procedure with the existing terminal and the communication protocol control of the ISDN line control unit 26 described later.

The timer 27 detects the end of the transmission data sent from the terminal, and therefore has, for example, a retriggerable timer circuit driven by a reception detection signal for each byte of the terminal transmission data, or a function equivalent thereto. CP
It is composed of a soft timer realized by software by the U circuit and detects the end of data when there is no received data for a predetermined time. In the present embodiment, the presence or absence of received data within a predetermined time is monitored by the timer 27 in order to detect the end of transmitted data from the terminal, but as another method, the end of data included in the received data is instructed. Control signal, eg E in the basic procedure
A control signal such as TX (End of Text) may be detected.

The calculation circuit 28 is composed of, for example, a counter circuit which counts up by a reception detection signal for each byte of the terminal transmission data, and counts the amount of transmission data from the terminal. The function of the calculation circuit 28 is the same as that of the C
It may be realized by software such as searching the number of received data in the RAM 23 by the PU circuit. The charge table 29 is a charge table based on various parameters (data amount, packet size, distance, day and night, weekdays and holidays, etc.) relating to the above-mentioned communication charges as judgment data for lowering communication charges, or a combination of the above parameters. The replacement type selection table is configured so that the optimum replacement type can be selected easily. Billing table 2
9 may be included in the ROM 23 of the CPU circuit. I
The SDN line control unit 26 provides an interface for opposite connection with the DSU for connecting with the ISDN line. For example, JT-V recommended by TTC for speed matching
The low speed data is interfaced to the 64 Kb / s B channel by 110 or the like. The ISDN line control unit 26 may be realized as including the function of the DSU.

FIG. 3 shows an example of a communication control sequence for explaining the characteristic operation of the terminal adapter according to the present invention. In FIG. 3, a conventional communication control procedure such as the above-mentioned V. Two
A call request is made to the terminal adapter 20 according to the present invention using 5bis or AT command. At this point, the terminal adapter 20 functions as a pseudo network for the data terminal 30, and returns a pseudo response to the data terminal 30 according to a predetermined procedure. The data terminal 30 determines that the network side is in a data receiving state and sends the data to the terminal adapter 20.

The terminal adapter 20 stores the data in the RAM 23 as described with reference to FIG. And
When the timer 27 detects the end of the received data, based on the amount of received data by the calculation circuit 28, the accounting table 29 is used to select either the circuit exchange or the packet exchange with the lowest communication charge. After that, the terminal adapter 20 functions as a pseudo ISDN data terminal for the network 31,
A call is made by designating the selected circuit-switched or packet-switched connection according to the same procedure as shown in the prior art of FIG. Thereafter, the received data from the data terminal 30 stored in the RAM 23 is sent to the network 31 in response to the network 31.

4 and 5 show an example of the processing flow of the communication control procedure of the terminal adapter according to the present invention described above. The solid line box indicates the terminal operation, the thick solid line box indicates the terminal adapter operation, and the dotted line box indicates the network operation. In FIG. 4, when the terminal issues a call request to the terminal adapter (S101), the terminal adapter accepts the call request and call request information (destination address etc.).
Is stored in the internal memory (S102, S103). Next, the terminal adapter sends a response message indicating that the data is in a state of accepting data, simulating the network side, to the terminal (S104). Upon receiving the response message, the terminal starts data transmission to the terminal adapter (S105, S106). The terminal adapter receives the data, stores it in the internal memory, counts the amount of the received data, and monitors the no-signal time or a predetermined data end control signal that continues for a predetermined time to end the transmission data from the terminal. Is detected (S107 to S10
9).

Next, in FIG. 5, when the terminal adapter detects the end of data, the charge for using circuit switching or packet switching is received data amount, destination telephone number (communication distance), date and time (day, night, weekday, holiday). ), And when packet exchange is used, it is further comprehensively calculated from the data division method (packet size) and the like to determine which of the exchanges is cheaper (S110 to S112).

6 to 9 are explanatory views showing an example of the above determination. FIG. 6 is an example of a simple exchange type selection table (billing table) showing whether either circuit switching or packet switching is advantageous in terms of charges when the transmission data amount and the distance from Tokyo to the destination are used as parameters. Is. Such a simple selection table is prepared for day, night, weekday and holiday respectively, and the above selection is performed by comprehensively judging each condition. For example, if the above table is used, it is possible to easily determine that circuit switching should be used for areas other than Tokyo when transferring data of less than 100 bytes. Of course, it is also possible to use the detailed charge table displayed as a direct charge to compare and calculate the use charges from the above various conditions and select the switching type of the line or packet.

FIGS. 7 to 9 are explanatory views showing an example of selection or combination of packet sizes for transferring data at a lower cost when packet switching is selected. FIG. 7 shows an example of selection of packet size with respect to data size and combination thereof. In FIG. 7, when a data size of 5632 octets is transmitted, a packet size of 2816 octets is selected in the A column, and it is transmitted twice. FIG. 8 is an explanatory diagram schematically showing the communication procedure in this case. In column B, the above 5
Data of 632 octets and 4096 octets and 1
It transmits once using each of the two packet sizes of 536 octets. FIG. 9 is an explanatory diagram schematically showing the communication procedure in this case.

In the case of the former, the charge is (column A in FIG. 7, FIG. 8), 4.9 yen (2,816 octets) × 2 times = 9.8.
It is a yen, and the charge in the latter case (column B in FIG. 7, FIG. 9) is
6.2 yen (4096 octets) + 3.2 yen (1536)
Octet) = 9.4 yen. Therefore, even if the same data amount is transmitted from the above example, the packet size selection /
It can be seen that the charge varies depending on the combination method, and in the case of this example, the latter is selected from the viewpoint of the charge. Further, the column C of FIG. 7 shows a case where a data size of 3072 octets smaller than that of the above example is transmitted, and in that case also, an example in which a wrong packet size is selected is disadvantageous in terms of price is shown. It is a thing. In other words, the charge in this case is 0.8 yen (256 octets) x
12 times = 9.6 yen, which is more expensive than in the case of column B.

Returning to FIG. 5 again, the circuit switching or packet switching is selected by comprehensively judging various charge parameters as described above (S112). When the circuit switching is selected, the terminal adapter specifies the circuit switching in the call setting message, and sends the received data from the terminal stored internally to the network side by the response message from the network (S113 to S11).
7). On the contrary, if packet switching is selected, packet switching is specified in the call setup message,
In response to a response message from the network, the received data from the terminal stored internally is sent to the network side as B channel packet information or D channel packet information (S113 to S117).

[0025]

As described above, according to the present invention, the data terminal can automatically and efficiently use the ISDN capable of performing both the circuit switching and the packet switching, and the cost required for the data communication. The reduction effect of is cumulatively significant.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a terminal adapter according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a terminal adapter according to the present invention.

FIG. 3 is a diagram showing an example of a communication control procedure for explaining the operation of the terminal adapter according to the present invention.

FIG. 4 is a flowchart showing an example (1) of a processing flow of a communication control procedure of the terminal adapter according to the present invention.

FIG. 5 is a flowchart showing an example (2) of the processing flow of the communication control procedure of the terminal adapter according to the present invention.

FIG. 6 is a diagram showing an example of a simple exchange type selection table in which a transmission data amount and a distance to a destination are parameters.

FIG. 7 is a diagram showing an example of selection of packet size with respect to data size and combination thereof.

FIG. 8 is an explanatory diagram schematically showing a case where 5632 octet data is transmitted in a packet size of 2816 octet in two divided transmissions.

FIG. 9 is an explanatory diagram schematically showing a case where 5632 octet data is transmitted with two packet sizes of 4096 octet and 1536 octet.

FIG. 10 is a diagram showing an example of a communication procedure for performing data communication between an existing terminal and a network via a conventional terminal adapter.

[Explanation of symbols]

1 ... Terminal 2 ... Terminal adapter 3 ... Terminal interface means 4 ... Pseudowire communication control means 5: Communication end detecting means 6 ... Terminal data storage means 7 ... Exchange type determination means 8 ... Line interface means 9 ... Pseudo terminal communication control means

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-104930 (JP, A) JP-A-4-124943 (JP, A) JP-A-4-329795 (JP, A) JP-A-3- 45053 (JP, A) JP-A-2-264536 (JP, A) JP-A-62-289028 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/14 H04L 12 / 64

Claims (3)

(57) [Claims] 1. A terminal for connecting a terminal to a network line.
-In the terminal adapter, pseudo for the terminal
Pseudo executing the access communication procedure with the line of the network
And line communication control means similar, and communication end detection means for detecting the end of the data transmitted from the terminal, the terminal data storage means for temporarily storing the data, the terminal de
Switching type determining means for selecting circuit switching or packet switching with a lower transmission fee of the data by calculating or comparing and determining various parameters based on the amount of data stored in the data storage means ; after completion of the exchange type determination unit network of circuit switching or packet switching selected by relative perform the connection communication procedure pseudo-terminal the terminal data
Pseudo terminal communication for sending data stored in the data storage means
A terminal adapter having a control means.
Ta . 2. The exchange type judging means has a billing table for judging a line charge by using the transmission data amount , the telephone number of the other party and / or the date and time as the parameter. Terminal adapter . 3. The communication end detecting means uses a timer means for detecting the end of the transmission data by a no-signal state which continues for a predetermined time during data transmission, and / or a control signal for instructing the end of the transmission data. 2. The tag according to claim 1, comprising transmission data end signal detecting means for detecting .
-Terminal adapter .