JPH10322458A - Modem system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of a communication error due to hung-up or a fault by changing a on-line wire from a main system control means section to a sub system communication section in the case of detecting the error. SOLUTION: In the case that a main system communication section 3 and a sub system communication section 6 have no hung-up and no fault, the main system communication section 3 conducts data communication. A hung-up or a fault takes place in the main system communication section 3, then a sub CPU 4 controls a changeover section 7 to change an on-line wire from the main system communication section 3 to the sub system communication section 6 and resets the main system, communication section 3 consisting of CPU 1 and a main modem section 2 to restore the system. The sub CPU 4 monitors an error in the main CPU 1 or the main modem section 2 and has a routine time reset processing means that resets the main system control means section 3 at each routine time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a modem system, and more particularly, to a system suitable for use in an unmanned environment.

[0002]

2. Description of the Related Art Generally, when digital data is transmitted using an analog line, means for converting digital data into an analog wave, transmitting the analog wave, and demodulating the analog wave on a receiving side is employed. Such modulation and demodulation processes are performed by a modulator and a demodulator, respectively, and generally, a device called a modem, which is a generic name for these, is used.

Incidentally, this modem also has a circuit configuration similar to that of a computer, and generally includes a CPU, a memory, and software. For this reason, an error is likely to occur due to surge or noise from the communication line, and a hang-up may occur in which the original function is stopped.

[0004] When a hang-up occurs, the reset switch of the modem is pressed to initialize the communication, and then the communication is resumed.

[0005]

However, there is no problem in the case where the modem is on the operator side and can be reset artificially, such as in ordinary personal computer communication or the Internet, but there is no problem. This can be a serious problem if the modem hangs up in an unattended facility, such as a wireless repeater at the top of a mountain.

[0006] This is because such equipment is often located in a remote location and it is difficult to go out due to the reset of the modem. In particular, robots such as data loggers for weather observation are often installed in polar regions, which has been a serious problem in terms of reliability. Even if the equipment can be remotely operated, if the modem itself hangs up, there is no way of remote operation, and the hang-up is a bottleneck of this kind of equipment.

Further, when a hardware failure occurs in the modem, even if it can be reset, it cannot be returned to a normal state. In this case, there was no way to recover except to recover and repair the modem.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a modem which does not cause a communication failure due to a hang-up or a failure.

[0009]

The present invention is configured as follows to solve the above-mentioned technical problems.

That is, a main communication unit 3 including a main CPU 1 and a main modem unit 2, a sub communication unit 6 including a sub CPU 4 and a sub modem unit 5, and one of the main communication unit 3 and the sub communication unit 6. And a switching unit 7 for switching and using the sub-line as an online line.
The PU 4 includes a monitoring processing stage that monitors an abnormality of the main CPU 1 or the main modem unit 2, a change processing stage that changes an online line from the main communication unit to the sub communication unit when an abnormality is detected as a result of the monitoring, A reset processing stage for resetting the CPU and the main modem unit.

Also, a main system communication unit 3 including a main CPU 1 and a main modem unit 2, a sub system communication unit 6 including a sub CPU 4 and a sub modem unit 5, and one of the main system communication unit 3 and the sub system communication unit 6. And a switching unit 7 for switching and using the line as an online line.
4 is a monitoring stage for monitoring an abnormality of the main CPU 1 or the main modem unit 2, and when an abnormality is detected as a result of the monitoring,
A change processing stage for changing an online line from the main communication unit 3 to the sub communication unit 6 and a regular reset processing stage for resetting the main communication unit 3 or the sub-modem unit 5 at regular intervals are provided.

In addition to these configurations, a ring detecting circuit for detecting a call from a public line, a ring latch circuit for holding a signal from the ring detecting circuit, a memory circuit, a memory backup circuit, and a display for displaying a state of a modem. The same holds true even if a container or the like is added.

The operation of the above configuration will be described. If neither the main communication unit 3 nor the sub communication unit 6 has hanged up or failed, the main communication unit 3
Performs data communication.

If a hang-up or a failure occurs in the main communication section 3, the sub CPU 4 controls the switching section 7 to change the online line from the main communication section 3 to the sub communication section 6, and The main communication unit 3 composed of the main CPU 1 and the main modem unit 2 is reset to recover.

If both hang up at the same time, the sub CPU 4 recovers by a regular reset operation. Extremely reliable operation occurs because there is little probability that both hardware will fail.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a modem system according to the present invention will be described in more detail with reference to the embodiments shown in FIGS.

The basic specifications of this modem system are as follows:
It looks like this: The communication line is one line, the applicable line is a telephone line or a two-wire dedicated line or a duplex wireless line (including public wireless telephones), an NCU (Netw
ork Control Unit) type is AA, dial type is dial pulse type or tone type, NCU control command is AT
Command compliant, communication method is full duplex, communication speed is 24
00 bps.

The basic configuration of the present modem system is as shown in FIG. In the figure, the switching unit A7a is R
It is connected to the S232C serial interface and to the data logger. On the other hand, the switching unit B7b is connected to a telephone line. The switching unit A7a and the switching unit B7b are switched by the sub CPU 4. That is, the switching unit A7a includes an RS232C serial interface,
The switching section B7b selectively connects the main communication section 3 or the sub communication section 6 to the telephone line and the main communication section 3 or the sub communication section 6. The switching unit A7a and the switching unit B7b constitute the switching unit 7.

The main communication section 3 comprises a main CPU 1 and a main modem section 2. On the other hand, the sub-system communication unit 6 includes a sub-CPU 4 and a sub-modem unit 5.

Therefore, by switching the switching section A7a and the switching section B7b simultaneously, the online line (signal line actually used) is connected to the main communication section 3.
And the sub-system communication unit 6 can be selected.

The sub CPU 4 includes a program,
The program includes a monitoring processing stage for monitoring an abnormality of the main modem unit 2, a change processing stage for changing an online line from the main communication unit to the sub communication unit when an abnormality is detected as a result of monitoring, a main CPU and A reset processing stage for resetting the main modem unit 2 is provided by software.

The sub CPU 4 has a regular reset processing stage for monitoring an abnormality of the main CPU 1 or the main modem unit 2 and resetting the main communication unit 3 at regular intervals. The abnormality is inspected by, for example, performing a self-loopback test once a day.

FIG. 2 shows a block diagram of the hardware.
It is inserted between a telephone line and an RS-232C-compliant output port sent from a terminal (not shown). RS
A switching unit A7a is connected to the -232C compliant output port, and ICs 8 and 9, which are serial / parallel converters, are connected to the output of the switching unit A7a.
The main system communication unit 3 and the sub system communication unit 6 are connected to these ICs 8 and 9, respectively.

The main CPU 1 has a static RAM 1
0 and an LCD 11 and an EEPROM 12, which are liquid crystal display units, are connected. On the other hand, the sub CPU 4 has a static RAM 13, a clock RTC 14, and an EEPROM.
15, a power supply monitoring unit 17 is connected. Also, RTC
The backup circuit 16 is connected to 14. A power adapter 18 is connected to the power monitoring unit 17 so that power is supplied.

The power monitor 17 outputs a reset signal and a power stop detection signal to the sub CPU 4.
A sub reset signal is output from the sub CPU 4 to the main CPU 1, the main modem unit 2, and the sub modem unit 5. The outputs of the main modem unit 2 and the sub-modem unit 5 are connected to a switching unit B7b, and the output of the switching unit B7b is connected to a telephone line. The output of the switching unit B7b is connected to a ring detection circuit 19 for detecting that a telephone call has been made. The output of the ring detection circuit 19 is connected to the main modem unit 2 and the sub-modem unit 5, and It is connected to the ring latch circuit 20. The main CPU 1 and the sub CPU 4 are connected to a dual port RAM.

The operation of the above configuration will be described with reference to the flowchart shown in FIG. Step 10
From 0 to Step 107, the operation in the main communication unit 3 is mainly shown, and from Step 110 to Step 125, the operation in the sub communication unit 6 is mainly shown.

First, start by turning on the power (step 10).
0) Then, in step 101, initial processing is performed. Thereafter, a self-test is executed in step 102, and the result is notified to step 114. Further, a loopback test is performed once a day (step 104). Then, the process proceeds to a communication process error detection process (step 105). Here, every hour (for example, 1
Is determined (step 10).
6) In the affirmative branch (every hour), reset of the main modem unit 2 is executed. On the other hand, the negative branch forms a loop leading to step 105.

Next, the operation of the sub-system communication section 6 will be described. The process proceeds from the start step 110 to the initial processing step 111, and in step 112, the main communication unit 3
Request a self test. Subsequently, at step 113, a self-test of the sub-system communication section 6 is executed. On the other hand, as for the result of step 103, it is determined in step 114 whether the result of the self-test was good. In the negative branch, it is determined in step 115 whether an error has occurred in the main communication unit 3. Here, in the negative branch (no error has occurred), the main communication unit 3 goes online in step 116 and moves to step 119. The affirmative branch of step 114 proceeds to step 117, in which a loopback test is instructed to the main communication unit 3 and executed in step 104, and in step 118
Move to. At step 118, the result of the loopback test is determined. The affirmative branch is monitored by the main communication section 3 (step 119), and it is determined whether or not it is time to perform a loopback test (step 12).
Move to 0. The positive branch goes to step 112,
The negative branch moves to step 119.

On the other hand, the negative branch of step 118 controls the switching unit 7 to switch the online line to the sub-system communication unit 6 (step 121). Then, a communication process error detection process (step 122) is executed to determine whether it is time to perform a loopback test (step 1).
Move to 23. The positive branch moves to step 112, and the negative branch moves to step 124 where it is determined whether it is every hour. The affirmative branch of step 124 shifts to step 125 for resetting the sub-modem unit 5, and the negative branch shifts to step 122.

The series of operation states are converted into predetermined codes and then automatically transmitted from the telephone line so that the receiving side can know them.

[0031]

According to the modem system of the present invention, when an abnormality occurs in the main communication unit due to a hang-up or a failure, the communication failure occurs because the sub CPU automatically changes the online line to the subsystem side. Never.
Further, since the sub CPU automatically resets the main CPU, the hang state can be eliminated immediately.

Further, a device having a regular reset processing stage for resetting the main modem unit and the sub-modem unit at regular intervals can always be operated in the best condition. In a device having a status transmission stage for self-diagnosing the main CPU and transmitting the result, the status of the modem can be known from the receiving side.

As described above, by using the present invention in an unmanned transmission device such as a data logger or a wireless relay station, it is possible to greatly improve reliability and simplify maintenance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a modem system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a modem system according to one embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of the modem system according to the embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main CPU 2 Main modem part 3 Main communication part 4 Sub CPU 5 Sub modem part 6 Sub communication part 7 Switching part

Claims (2)

[Claims] 1. A main communication unit including a main CPU and a main modem unit, a sub communication unit including a sub CPU and a sub modem unit, and one of a main communication unit and a sub communication unit is switched and used as an online line. The sub CPU changes the online line from the main communication unit to the sub communication unit when an abnormality is detected as a result of the monitoring. Change processing stage and main CPU
And a reset processing stage for resetting the modem. 2. A main communication unit including a main CPU and a main modem unit, a sub communication unit including a sub CPU and a sub modem unit, and one of a main communication unit and a sub communication unit is switched and used as an online line. The sub CPU changes the online line from the main communication unit to the sub communication unit when an abnormality is detected as a result of the monitoring. And a periodic reset processing stage for resetting the main communication unit or the sub-modem unit at regular intervals.