JPH0325112B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] In a data communication network control device, an answer tone and a tone can be generated using a general-purpose microprocessor and a small number of peripheral circuits, without using a dedicated LSI for tone generation.
Generates touch tone, etc.

[Industrial application field]

The present invention relates to a network control device used when maintaining exchanges and data terminals through communication lines.

[Conventional technology]

FIG. 2 shows an example of a conventional data communication system.

In the figure, 1 and 2 are data terminals, 3 and 4 are modems, 5 and 6 are network control devices, and 7 is a switch.
8 and 9 are communication lines. The same symbols represent the same objects throughout the figures below.

When the data terminal 1 and the data terminal 2 perform data communication via the exchange 7, a device configuration as shown in FIG. 2 is normally adopted.

The modems 3 and 4 are devices connected to the data terminals 1 and 2, respectively, and serve as modems for converting the input and output signals of the data terminals 1 and 2 into a symbol format suitable for the communication lines 8 and 9.

The network control devices 5 and 6 are devices used when using public communication lines, and are called NCUs, and have functions such as sending dial signals necessary for controlling the communication network, sending answer back signals, and touch tones. ing.

FIG. 3 shows an example of a circuit of a conventional network control device.

In the figure, 10 is an overall control section, 11 is an answer tone generation section, and 12, 13, and 14 are interface sections, respectively.

As shown in FIG. 3, a conventional network control device includes an interface section 12 having an interface function with a terminal, an interface section 13 having an interface function with a switching network via a line, and an interface function with a modem. Interface section 1 having
4, an answer back tone generating section 11, and an overall control section 10 for comprehensively controlling various devices such as these.

Furthermore, in configuring the answer back tone generator 11, a dedicated LSI or logic circuit is used to generate a predetermined signal tone (including a touch tone, etc.), and a dedicated logic circuit is also used to output it to the line. was.

[Problem that the invention seeks to solve]

However, in recent equipment configurations, the modem and network control device are often housed in the same case in order to downsize the device.

As is well known, recent modem devices utilize microprocessors to configure their circuits. Therefore, by using this microprocessor to generate an answer block tone, etc., and by outputting the above signal to the line using a logic circuit such as a latch circuit built into the modem, the device can be made smaller and more economical. It is an object of the present invention to achieve this goal.

[Means for solving problems]

The above problem can be solved by accommodating the modem and the network control device in the same case as shown in FIG. , and uses a general-purpose microprocessor 20 provided in the modem in a time-sharing manner to selectively read various signal tone data stored in the table 24 in advance and input it to the latch circuit 21. However, this problem can be solved by converting the data input to the latch circuit 21 into an analog signal sound by the DA converter 22 and outputting it to the line via the output filter 23.

[Effect]

According to the present invention, a general-purpose microprocessor used in a modem is used in a time-sharing manner to read a predetermined signal tone from a table, store it in a latch circuit, convert this data into an analog quantity, and send it to the line. Therefore, there is no need for a dedicated LSI or logic circuit as in the conventional method, and the effect is that the device can be made smaller and more economical.

〔Example〕

FIG. 1 is a diagram showing an embodiment of an answer back tone generation method according to the present invention.

In the figure, 20 is a general-purpose microprocessor, 21 is a latch circuit, 22 is a DA converter, 23 is an output filter, and 24 is a table.

In the present invention, a dedicated LSI or logic circuit is not used to generate touch tones, answer back tones, etc., and the answer back tone generator 11
Instead, a generation circuit using a general-purpose microprocessor 20 built into the modem 3 (or modem 4) as shown in FIG. The above signal is output to the line using a filter, an output filter, and a table.

That is, data obtained by sampling signal tones such as an answer tone and a touch tone is created in advance and stored in the table 24, and the general-purpose microprocessor 20 operates in a time-sharing manner according to instructions from the overall control section 10.

The overall control unit 10 checks the status of the terminal 1 (or terminal 2) in response to a call from the other station, and instructs the general-purpose microprocessor 20 to generate a predetermined signal tone.

Upon receiving an instruction to generate a signal tone from the overall control section 10, the general-purpose microprocessor 20 reads out a predetermined signal tone from the table 24 and inputs it to the latch circuit 21.

If the signal tone data stored in the table 24 has, for example, an 8-bit structure, the most significant bit (MSB bit) is a sign bit, and the following 7 bits are data bits.

Signal sound data with this structure is transmitted to the latch circuit 21.
When input to the latch circuit 2, the overall control section 10
1 data is transferred to the DA converter 22, converted into an analog signal to create a positive or negative polarity analog signal, and sent to the communication line 8 (or communication line 9) via the output filter 23.

〔Effect of the invention〕

As explained in detail above, according to the present invention, it is possible to generate a signal sound and output it to the line using a general-purpose microprocessor without using a dedicated LSI or logic circuit, thereby making the device more compact and economical. It has the great effect of being able to measure the change in

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of an answer back tone generation method according to the present invention. FIG. 2 shows an example of a conventional data communication system. FIG. 3 shows an example of a circuit of a conventional network control device. In the figure, 1 and 2 are data terminals, 3 and 4, respectively.
1 is a modem, 5 and 6 are network control devices, 7 is a switch, 8 and 9 are communication lines, 10 is an overall control unit, and 1 is a network controller.
1 is an answer back tone generation section, 12, 13,
and 14 are interface sections, 20 is a general-purpose microprocessor, 21 is a latch circuit, and 22 is a D
-A converter, 23 is an output filter, and 24 is a table.

Claims (1)

[Claims] 1. A modem and a network control device housed in the same case, a latch circuit 21 provided in the modem,
By using the D-A converter 22, the output filter 23, and the table 24, and by using the general-purpose microprocessor 20 provided in the modem in a time-sharing manner, the table is processed by the general-purpose microprocessor 20. Selectively read out various signal sound data stored in advance in the D-24 and input it to the latch circuit 21, and input the data input to the latch circuit 21 to the D-24.
An answer tone generation method characterized in that the A converter 22 converts the signal into an analog signal and outputs the signal to the line via the output filter 23.