JPH04337947A - Data communication system - Google Patents

Abstract

PURPOSE:To reduce a shared MODEM, to simplify system configuration and to reduce system cost by providing plural speed changing means in one MODEM interface trunk device. CONSTITUTION:Data terminal interface devices 21 and 22 are equipped with respectively different speed changing systems. A MODEM interface trunk device 4 is provided to interface a shared M0DEM 5-2 for converting data signals into analog signals in the case of executing data communication between data terminals 11 and a data terminal 12 connected through a MODEM to an analog line. At this device 4, the data signals changing the speed at the data terminal interfaces 21 and 22 are changed into the original data speed, transmitted to a MODEM 5-1 and converted into analog signals. The device 4 is equipped with the plural kinds of speed change circuits, selects one circuit corresponding to the speed change of the data terminal interface devices 21 and 22 connected according to the instruction of a central processing unit 9 and correctly converts the signals into the original data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to data communication in a digital electronic exchange, and more particularly to data communication using a modem in common.

0002

2. Description of the Related Art In a conventional data communication system, as shown in FIG. Modem 5-
The modem interface trunk devices 81 and 82 that interface with the data terminals 2 and 5-3 are prepared for each type of data terminal interface device 21 and 22, and the modem interface trunk devices 81 or 82 that match the speed conversion method of the data terminal 11 to be connected during communication are prepared. was selected and data communication was performed. The speed conversion method of data terminal interface device 21 and the speed conversion method of modem interface trunk device 81 are of the same type, and similarly, speed conversion methods of data terminal interface device 21 and modem interface trunk device 81 are of the same type.

0003

[Problems to be Solved by the Invention] In this conventional data communication method, it is necessary to prepare modem interface trunk devices corresponding to the number of speed conversion methods provided in the data terminal interface device, and modem interface devices must also be prepared. This creates a problem in that an extra amount is required, which complicates the system configuration and increases costs.

An object of the present invention is to provide one modem interface device with a plurality of speed conversion means and a speed conversion selection means for selecting one speed conversion means from the plurality of speed conversion means, thereby reducing the number of shared modems and reducing system costs. The object of the present invention is to provide a data communication method that enables the reduction of the amount of data.

[0005]

[Means for Solving the Problems] The data communication system of the present invention uses a common modem for data communication via an analog line from a data terminal connected to a digital line via a digital electronic exchange. In a data communication system in a digital exchange equipped with a modem interface trunk device for use in the digital electronic exchange, the modem interface trunk device includes means for interfacing analog signals with the modem; PCM signal conversion means for connecting to the division switch; means for interfacing digital signals with the modem; a plurality of types of speed conversion means for connecting the digital signal to the time division switch; and speed conversion selection means for selecting one speed conversion means from the plurality of types of speed conversion means in response to an instruction from a central processing control unit of the exchange.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a relay system diagram showing an embodiment of the present invention. The data terminal interface devices 21 and 22 connected to the digital line each have different speed conversion methods. For example, unique speed conversion method and ISDN
The CCITT Recommendation V. 110/V. 120
There are speed conversion methods such as Here, when performing data communication between the data terminal 11 accommodated in these digital lines and the data terminal 12 connected to the analog line via a modem, a shared modem 5 converts the data signal from the digital line into an analog signal. -2, there is a modem interface trunk device 4.

In the modem interface trunk device 4, the speed of the data terminal 1 is converted by the data terminal interface devices 21 and 22 in order to connect to the time division switch.
1 data signal is speed-converted back to the original data and sent to the modem 5-1 to be converted into an analog signal. The modem interface trunk device 4 has multiple types of speed conversion circuits, and selects one that matches the speed conversion of the data terminal interface devices 21 and 22 connected according to instructions from the central processing control device 9, and correctly converts the data to the original data. do.

FIG. 2 is a functional block diagram of the modem interface trunk device 4 used in the present invention. The signal from the data terminal 11 whose speed has been converted by the data terminal interface devices 21 and 22 is inputted to the time division switch interface circuit 41 of the modem interface device 4 via the digital line interface device 6 and the time division switch 3. The signal from this data terminal 11 is selected by the speed conversion circuit selection circuit 47-1, and then converted into the original data by the speed conversion circuits 46-1 to 46-n. 2. The data is sent to the modem 5-2 through the modem digital interface circuit 44 and the digital line 200. The signal from the modem 5-2 converted into an analog signal is input to the modem analog interface circuit 43 via an analog line 400. The analog signal from this modem 5-2 is sent to the PCM signal conversion circuit 4.
5 becomes a PCM signal, and as shown in FIG.
, and is sent to the modem 5-1 via the analog line 300. The modem 5-1 transfers this signal to the digital line 1.
00 to the data terminal 12. The same goes for the opposite direction. The speed conversion circuit selection circuits 47-1 and 47-2 are
Controlled by the central processing control unit interface circuit 42 according to instructions from the central processing control unit 9, a speed conversion circuit similar to that of the connected data terminal interface devices 21 and 22 is selected. Note that the speed conversion circuit selection circuits 47-1 and 47-2 operate in conjunction with each other.

0010

[Effects of the Invention] As explained above, the present invention provides a single modem interface trunk device with a plurality of speed conversion means, thereby reducing the number of shared modems, facilitating system configuration, and reducing system costs. It has this effect.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a relay system according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of modem interface trunk values used in FIG. 1;

FIG. 3 is a relay system diagram of a conventional data communication system.

[Explanation of symbols]

11, 12 Data terminals 21, 22 Data terminal interface device 3
Time division switch 4 Modem interface trunk devices used in the present invention 5-1 to 5-3 Modem 6 Digital line interface device 7
Analog line interface device 81, 82
Conventional modem interface trunk device 9 Central processing control device 41 Time division switch interface circuit 42
Central processing controller interface circuit 43
Modem analog interface circuit 44 Modem digital interface circuit 45 PCM signal conversion circuit 46-1 to 46-n Speed conversion circuit 47-1 to 4
7-2 Speed conversion circuit selection circuit 100, 200
Digital line 200,400 Analog line

Claims (1)

[Claims] Claim 1: A digital device equipped with a modem interface trunk device for common use of a modem used when data communication is performed via an analog line from a data terminal connected to a digital line via a digital electronic exchange. In data communication systems in exchanges,
The modem interface trunk device includes means for interfacing analog signals with the modem, PCM signal conversion means for connecting the analog signals to a time division switch of the digital electronic exchange, and a means for interfacing analog signals with the modem. means for interfacing digital signals; a plurality of types of speed conversion means for connecting the digital signals to a time division switch; and speed conversion selection means for selecting one speed conversion means.