JPH03102946A - Private line connection method - Google Patents

Abstract

PURPOSE:To reduce the line connection time by allowing a computer (CMP) in the caller mode to send an ATD command at a variable period and a CMP in the called party mode to send an ATA command at a constant period to an AT MODEM. CONSTITUTION:An ATD command issue means 4 of a caller CMP 1S issues an ATD command to an AT MODEM 2S when a private line 3 is connected and starts a command issue interval variable timer 6. The CMP 1S revises the setting time of the timer 6 when no return information comes from the MODEM 2S even when the setting time of the timer 6 elapses after the issue of the ATD command and issues the ATD command again. On the other hand, when the called CMP 1R connects to the line 3, an ATA command is issued from an issue means 5 to an AT MODEM 2R to start a constant period timer 7. When no return information comes from the MODEM 2R even after the setting time of the timer 7 elapses after the issue of the ATA command, the AT command is issued again.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a line connection method in a system in which two computers are connected one-to-one through a dedicated line via a so-called AT modem to exchange data. Here, AT modem is a modem with intelligence.
A modem that performs operations such as calling a remote modem in response to various commands called ENT I ON commands.

[Conventional technology]

Connect two computers to one using a dedicated line via an AT modem.
When connecting to a 1-to-1 connection and bringing the line from an offline state to an online state, the computer on the AT modem side set for outgoing and the computer on the AT modem side set for incoming mode bring the line online. For example, each calling and receiving side must issue a line connection command or perform corresponding processing at the same time. For this reason, conventionally, humans on the calling and receiving sides communicated with each other using separate lines, etc., and manually performed hook operations for the AT modems on each side.

[Problem to be solved by the invention]

However, the above line connection method has the problem of being troublesome and time consuming. Therefore, it is an object of the present invention to provide a dedicated line connection method that can solve this problem.

[Means to solve the problem]

In order to solve the above problems, the method of the present invention provides two computers (Is, IR, etc.), an AT modem (2S, 2R, etc.) belonging to each computer,
In a system in which the two AT modems are connected by a dedicated line (such as 3) and the two computers exchange data with each other via the AT modem and the dedicated line, when the dedicated line is connected, Until the line connection is successful, one of the computers on the calling side gives an ATD command (to call the other party's AT modem for making a call) to the AT modem belonging to itself in a first cycle;
Similarly, the computer on the receiving side gives an ATA command (indicating that the other party's AT modem should be called to receive a call) to the AT modem belonging to itself in the second cycle, and in this case, One of them is fixed, and the other is made to change sequentially by a predetermined amount of change between at least predetermined upper and lower limit values.

[For use]

A computer whose AT modem is in sending mode sends an ATD command to the AT modem at variable intervals, and a computer whose AT modem is in receiving mode sends an ATA command to the AT modem at regular intervals.
The command is sent to the T modem to automatically create an opportunity for the output time of the ATD command and the output time of the ATA command to match.

【Example】

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a system configuration diagram as an embodiment of the present invention. In the same figure, 3 is a dedicated line, 2 (2S.2R
) are AT modems installed at both ends of this circuit la3. 1 (15. IR) is the AT that belongs to itself
These are computers that exchange data with each other via the modems 2S and 2R and the dedicated line 3. In this example, for convenience, Is is assumed to be the originating side, and IR is assumed to be the receiving side. Further, in accordance with this, the AT modem 2s is set in advance to a calling mode, and the AT modem 2R is similarly set to a receiving mode. Further, 4 and 6 are ATD command issuing means and a command issuance interval variable timer as partial functional units that are considered to share a part of the computer ISO function, and 5 and 7 are also part of the computer IR function. Then, the ATA command issuing means and fixed period timer are considered as partial functional units. FIGS. 2 and 3 are flowcharts showing the main operations of the computers Is and IR, respectively. The following 20-2
Reference numeral 6 indicates the step in FIG. 2, and reference numerals 30 to 36 indicate the steps in FIG. Next, the operation shown in FIG. 1 will be explained using FIGS. 2 and 3. When the sending computer IS (ATD command issuing stage 4) attempts to connect the dedicated line 3, it issues an ATD command to the AT modem 2S (20.21) and starts the command issuance interval variable timer 6 ( 22). Then, the AT modem 2 receives return information in response to the issued ATD command (that is, information indicating whether the line connection is established or not established).
When S returns the line connection failure to computer IS (23, branch Y → 24, branch N), when the timer 6 has timed out (26, branch Y), the ATD computer of computer IS (23, branch Y → 24, branch N) Issuance method 4) is ATD again
A command is issued to the AT modem 2S (21), and if it returns a line connection or establishment, the process ends (23, branch Y → 2
4, Branch Y). The computer Is issues the ATD command and then
The time is monitored until the return information of AT modem 2S is returned, and the AT
If the return information is not returned from the AT modem 2S even after the time set in the command issuance interval variable timer 6 has elapsed after issuing the D command, issue the ATD command again (
21-23, branch N→25, branch Y→21). The set time of this command issue interval variable timer 6 is gradually increased from the minimum value, and when it reaches the maximum value, it is returned to the minimum value. The minimum value is a predetermined value between 1 second and 5 seconds, and the maximum value is a predetermined value between 5 seconds and 20 seconds. The increment value of this set time is a predetermined value between 1 second and 5 seconds. On the other hand, when the computer IR on the receiving side (the ATA command issuing means 5) attempts to connect the dedicated line 3, the ATA
A command is issued to the AT modem 2R (30.31), and the periodic timer 7 is activated (32). and issued A
When the AT modem 2R returns line connection failure to the computer IR as return information in response to the TA command (33, branch Y → 34, branch N), it waits for the timeout of the timer 7 (36, branch Y ), computer IR
(ATA command issue 1,000 steps 5) issues an ATA command to AT modem 2R again (31), and ends if it returns a line connection command (33, branch Y → 34, branch Y) ．． The computer IR monitors the time from when the ATA command is issued until the return information of the AT modem 2R is returned, and after the ATA command is issued, the return information is not returned from the AT modem 2R even after the set time of the periodic timer 7 has elapsed. If it does not come, issue the ATA command again (31~
33, branch N → 35, branch Y → 31). The set time of this periodic timer 7 is set to a predetermined value between 5 seconds and 15 seconds.

【Effect of the invention】

According to the present invention, since the computer in which the AT modem is in the transmission mode sends the ATD command to the AT modem at variable intervals, the computer in which the AT modem is in the reception mode can quickly and easily respond to the ATA commands issued to the AT modem at regular intervals. Can be synchronized.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram as an embodiment of the present invention, FIG. 2 is a flowchart showing the main operations of the sending computer in FIG. 1, and FIG. 3 is a flowchart showing the operation of the receiving computer in FIG. This is a flowchart showing the main operations. 1 (IS.IR')
: Computer, 2 (2S. 2R): AT modem, 3: Dedicated line, 4: ATD command issuing means, 5:
ATA command issuing means, 6: command issuing interval variable timer, 7: fixed period timer. Departing I member 11 Arriving I = I ^1 {

Claims (1)

[Scope of Claims] 1) Two computers and an AT modem belonging to each computer, the two AT modems are connected by a dedicated line, and the two computers are connected to the AT modem and the dedicated line. In a system in which data is mutually exchanged via the dedicated line, when the dedicated line is connected, the sending computer among the computers sends an ATD command to the AT modem belonging to itself in the first cycle until the line connection is successful. Similarly, the receiving side computer is configured to give an ATA command to the AT modem belonging to itself in a second period, and at this time, one of the first or second period is fixed, and the other is set to at least a predetermined period. 1. A dedicated line connection method characterized in that the value is sequentially changed by a predetermined amount between upper and lower limit values.