JP2000124967A - Data transmission equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover a communication disable state caused by erroneous setting in the communication setting system of RS232C. SOLUTION: Inside a main storage device 30, two storage areas are provided for storing the setting contents of RS232C port P, and certain fixed communication setting is stored in default setting information 30a1, and arbitrary communication setting is stored in a custom setting information 30a2. Besides, an input/ output register 34 holds information showing whether a maintenance console 27 is connected or not corresponding to the signal state of RS232C port P. When a power source is turned on, a central processing unit 29 refers to the stored contents in the input/output register 34, and when the maintenance console 27 is connected, the custom setting information 30a2 is set to a communication controller 33, but when the console is not connected, the default setting information 30a1 is set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an RS232C port in a data transmission device, and more particularly to a data transmission device related to communication settings.

[0002]

2. Description of the Related Art In recent years, data communication for transmitting data by connecting a terminal such as a computer to another computer has become popular. First, an example of a connection configuration for performing such data communication will be described with reference to FIG.

FIG. 3 is a block diagram showing an example of a data transmission system for controlling data transmission in which a data transmission device, a terminal device, and a maintenance console are connected. Terminal devices 2 and 3 are connected to the data transmission device 1, a data transmission device 4 is connected below the system transmission device 1, and terminal devices 5 and 6 are connected thereto. Is connected to a maintenance console 8 via an RS232C cable 7.

[0004] In each data transfer, a packet is transferred in an arbitrary byte unit, and the components of the packet are mainly composed of "destination address, source address,
Transfer byte length, user data, and error control data. "

[0005] When a packet is transmitted from the terminal device (2, 3, 5, 6), the transmission device (1, 4) is connected to the terminal device (2, 3, 5, 6) connected under the transmission source address. Is stored.

Here, as an example, a case where data transfer is performed between the terminal device 5 and the terminal device 3 will be described.

When a packet is transmitted from the terminal device 5,
The data transmission device 4 collates the destination address with the stored terminal address of the subordinate. Here, since there is no corresponding address, the packet is further transferred to the system transmission apparatus 1. The system transmission device 1 also checks the destination address and transmits the packet to the corresponding terminal device 3.

[0008] Unlike the computers and the like, such transmission devices 1 and 4 usually do not require manual operation for communication setting and the like, and do not have an input / output device such as a console. Therefore, when performing maintenance work such as various settings and internal tests in the transmission devices 1 and 4, a maintenance console 8 is separately prepared and connected by the RS232C cable 7.

[0009] Such a maintenance console 8 is not connected to the flat console, and the RS232C cable 7 is connected if necessary.
This is an emergency console connected to the data transmission device 1 via the.

Incidentally, the RS232C transmission performed using the RS232C cable 7 or the like has already been standardized with the contents of "connector pin numbers, signal names and their meanings" as shown in FIG. 4 and has been widely adopted in various devices. I have.

There is an example of a conventional data transmission device configured as shown in the block diagram of FIG. RS23
The maintenance console 10 is connected to the RS 23 via the 2C cable 9.
The data transmission device 11 connected to the 2C port P as necessary has a central processing unit (CPU) 12, a main storage device (MEM) 13, and a non-volatile storage device (FME).
M) 14, local bus 15, communication controller (S
A PC 16, an input / output register (IOR) 17, and a data transmission control unit 18 are provided. The central processing unit 12, the main storage device 13, and the non-volatile storage device 14 are connected via a local bus 15.

A communication controller 16 is connected to the local bus 15, and an input / output register 17 indicating the state of the communication controller 16 is also connected. Also,
The central processing unit 12 is connected to a data transmission control unit 18 for controlling data transmission with the outside.

Therefore, when the power is turned on to the data transmission device 11 and a predetermined initialization process is completed,
The central processing unit 12 copies the storage contents of the nonvolatile storage device 14 to the main storage device 13.

The nonvolatile storage device 14 stores configuration information 14a for making communication settings of the communication controller 16, and stores the same information in the main storage device 1.
3 is stored as configuration information 13a.

The central processing unit 12 makes communication settings for the communication controller 16 based on the contents of the configuration information 13a. In addition, R is set to RS232C port P.
When the maintenance console 10 is connected via the S232C cable 9, information as to whether or not the RS232C port P is in a communicable state is stored in the input / output register 17, and the central processing unit 12 connects the local bus 15 to the local bus 15. By accessing the input / output register 17 through the interface, it is possible to know whether or not communication is possible.

The configuration information 13a includes R
S232C port P communication speed, data length, parity,
There are setting contents such as a stop bit length, and the setting contents can be referred to from the maintenance console 10 and the setting contents can be arbitrarily changed according to the use environment. When the settings are changed,
The configuration information 13a and 14a of both the main storage device 13 and the nonvolatile storage device 14 are updated.

Since the nonvolatile storage device 14 is a nonvolatile storage device, the setting contents of the RS232C port P can be stored even when the power is turned off.

The technique described so far is for arbitrarily setting the communication speed or other parameters in the RS232C transmission. The communication speed setting in the RS232C transmission is disclosed in, for example, JP-A-63-207246 (particularly, The communication speed can be automatically identified and the communication speed can be set as shown in FIG. 1 of the specification and the description thereof).

The content is that the communication speed is automatically identified by counting the clock pulses during the period when the start bit signal is generated in the RS232C transmission. It is configured as shown.

Therefore, the transmission signal S of the RS232C and the output of the output terminal Q are output through the OR gate 19 to the clock terminal C.
The output of the output terminal Q of the flip-flop 20 supplied to LK1 is supplied to the end signal terminal END of the central processing unit (CPU) 21. At the same time, the output of the output terminal Q is
The enable terminal E of the counter 23 via the OR gate 22
N. The clock terminal CLK of the counter 23
2, the output of the pulse generator 24 is supplied through an OR gate 25. Accordingly, the communication speed of the transmission signal S of the RS232C is identified by the count value of the counter 23 at this time.

The communication speed of the transmission signal S of the RS232C is
Assuming that transmission at 1200 bps and 300 bps is enabled, the clock frequency of the pulse generator 24 is set to 10
kHz. For this reason, the communication speed is 1200 bps
In the case of, the count value of the counter 23 becomes 9 or 8, and in the case of 300 bps, it becomes 34 or 33.

The central processing unit 21 fetches the output data of the counter 23 from the data bus B, identifies that the communication speed is 1200 bps or 300 bps from each count value, and based on the result, a communication speed switching signal or the like. Is output to the network control unit (NCU) and the modem (MODEM) together with the data of the transmission signal S supplied to the serial port A.

The reset terminal RES of the central processing unit 21
The reset signal output from the ET is a flip-flop 2
0 and a reset terminal R provided for each of the counters 23
1, R2, and at the same time, to the enable terminal EN of the counter 23 via the OR gate 22, and is controlled so that the above-described operation is properly performed.

By adopting such a technique, if only the communication speed of the maintenance console 10 shown in FIG. 5 described above is changed, the communication speed of the communication controller 16 is automatically set. There is no need to set the communication speed of the communication controller 16, and the setting need only be made when changing other parameters such as the data length, parity, and stop bit length.

[0025]

However, the above-mentioned conventional system has the following first and second problems.

The first problem is that characters may be garbled in the maintenance console and communication may not be performed normally. More specifically, the maintenance console is not permanently installed in the data transmission device as described above, and the communication setting of the RS232C port can be freely changed depending on the installation environment and installation conditions of the data transmission device. Therefore, the communication setting of the RS232C port in each data transmission device is various.

When setting the communication of the RS232C port from the maintenance console, there is no problem because the communication speed is automatically identified. However, if the data length is erroneously set to 8 bits, it is set to 7 bits. If you do,
Since the communication settings are different between the two, garbled characters occur and communication cannot be performed normally.

The second problem is that when the communication settings of the RS232C port are changed, the changed contents are also written in the configuration information of the nonvolatile memory device (FMEM) in order to save the changed contents of the communication settings. Therefore, the first
In the case where the wrong setting described in the above problem is performed, it is not possible to recover the state in which communication is impossible even if the power is turned off.

Therefore, an object of the present invention is to recover a state in which communication has become impossible by making an incorrect communication setting to the RS232C port. Even if you use a maintenance console that cannot support the
An object of the present invention is to provide a data transmission device capable of reliably performing C communication.

[0030]

To achieve the above object, the data transmission apparatus of the present invention employs the following characteristic configuration.

(1) In a data transmission device to which a maintenance console can be connected via an RS232C cable, when the maintenance console is connected via the RS232 cable, communication is performed with arbitrarily set communication settings. When the RS232C cable is not connected, communication is performed with default communication settings.

(2) The data transmission apparatus described in (1) above is configured by storing configuration information having both storage areas of default setting information of fixed communication settings and custom setting information of arbitrarily set communication settings. It is configured to have storage means for storing.

(3) The storage means of (2) is composed of a main storage device and a non-volatile storage device which can access data via a local bus.

(4) The data transmission device of (3) performs communication setting of an RS232C port based on configuration information of the main storage device and the non-volatile storage device, and performs communication setting between the main storage device and the non-volatile storage device. And a communication controller for accessing the non-volatile storage device and reading and writing the configuration information via the local bus.

(5) The data transmission apparatus of (4) is provided with an input / output register for connecting the maintenance console to the RS232C port and storing information as to whether the RS232C port is in a communicable state. The configuration is as follows.

(6) The data transmission device according to any one of the above (3) to (5) can be used for data access between the main storage device and the non-volatile storage device, which is performed via the local bus. It is configured to be able to perform based on the control by the communication controller and the output of the input / output register.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a data transmission device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. Note that this embodiment is an example in which a data transmission system similar to that shown in FIG. 3 is formed.

A data transmission device 28 to which a maintenance console 27 is connected to an RS232C port P as needed via an RS232C cable 26 has a central processing unit (CPU) 29, a main storage device (MEM) 30, A non-volatile storage device (FMEM) 31, a local bus 32,
Communication controller (SPC) 33, input / output register (I
OR) 34 and a data transmission control unit 35 are provided.

The central processing unit 29, the main storage device 30, and the non-volatile storage device 31 are connected via a local bus 32. A communication controller 33 is connected to the local bus 32, and an input / output register 34 indicating the state of the communication controller 33 is also connected. Further, the central processing unit 29 is connected to a data transmission control unit 35 for controlling data transmission with the outside.

Such a non-volatile storage device 31 has the RS2
The configuration information 31a of the 32C port is stored, and has a recording area for default setting information 31a1 and custom setting information 31a2.

The main storage device 30 also stores the same configuration information 30a as the non-volatile storage device 31, and has a storage area for default setting information 30a1 and custom setting information 30a2.

Data transmission device 28 and maintenance console 27
RS232C communication is made on the DTE side, and when connecting each other, an RS232C cable 26 of the same standard as that described with reference to FIG. 4 is used.

Next, the operation of the data transmission apparatus according to the present embodiment will be described with reference to the flowchart shown in FIG.

When the power of the entire data transmission device 28 is turned on, the central processing unit 29 operates as follows.
Is copied to the main storage device 30. Therefore, the configuration information 30a of the main storage device 30
Has the same content as the configuration information 31a of the nonvolatile storage device 31. Also, RS232C port P
Is connected to the maintenance console 27, the R shown in FIG.
D indicating that the connection destination based on the S232C standard can operate
The R signal is enabled, and the signal state is stored in the input / output register 34.

The central processing unit 29 includes an input / output register 34
(Step S1), if the DR signal is enabled, it is determined that communication is possible (YES), and in the next step S2, the custom setting information 30a2 stored in the main storage device 30 is communicated. This is set for the controller 33. If step S1 is NO, ie,
If the DR signal is disabled, the next step S
In step 4, the default setting information 30a1 stored in the main storage device 30 is set in the communication controller 33.

In the next step S4, the maintenance console 2
7 to the RS232C port P, and the next step S3
To perform communication from the maintenance console 27. This step S
Step 3 is similarly performed after execution of step S2 executed when the DR signal is in the enable state.

When the communication setting of the RS232C port P of the maintenance console 27 is changed, the data transmission control unit 35 operated by the central processing unit 29 sends the custom setting information 30a2 in the main memory 30 and the custom setting information 30a2 in the nonvolatile memory 31. The setting contents are written to both storage areas of the setting information 31a2.

When the communication settings of the RS232C port P are read from the maintenance console 27, the contents stored in the custom setting information 30a2 in the main storage device 30 are referred to.

If the setting contents are incorrect when the communication setting of the RS232C port P is made, the RS232C port P becomes in a state where communication is impossible unless the same setting is made on the maintenance console 27. In order to recover this state, RS23
It is necessary to remove the RS232C cable 26 from the 2C port P and to turn on the power to the entire data transmission device 28 again.

The removal of the RS232C cable 26 disables the DR signal to the input / output register 34, so that the default setting information 30a1 is set in the communication controller 33. The default setting information 30a1 is a fixed setting and is a known setting, so that the same setting as the default setting information 30a1 can be performed on the maintenance console 27.

Therefore, by connecting the RS232C cable 26 to the RS232C port P again,
The 232C port P is temporarily in a communicable state. Here, by re-setting the communication settings of the RS232C port P from the maintenance console 27, it is possible to recover the communication disabled state in the custom settings.

As described above, since the RS232C port P is in a state in which communication is possible again, the custom setting incorrectly set from the maintenance console 27 can be corrected.

The RS232C port P is 115.2.
If the communication speed is set at kbps and the maintenance console 27 supports only the communication speed up to 9.6 kbps, the connection is first made with the default setting according to the above-described procedure, and the custom setting is performed from the maintenance console 27 by 9.1.
It is sufficient to change the setting to 6 kbps, and even if the setting contents of the RS232C port P are forgotten, the contents of the custom setting can be referred to by the above procedure.

Although the preferred embodiment of the data transmission apparatus of the present invention has been described in detail above, the present invention should not be limited to only such embodiment, and various modifications and changes can be made in accordance with a specific application. Of course, it is.

[0056]

As described above, when the maintenance console is connected via the RS232 cable, the data transmission apparatus of the present invention performs communication with the communication setting arbitrarily set, and the RS232C cable is used. When the connection is not established, the communication is performed with the default communication setting, so that the following remarkable effects can be obtained.

The first effect is that, by setting two storage areas of the default setting and the custom setting in the setting of the RS232C port, an incorrect communication setting is performed.
Even if communication becomes impossible with the custom settings, reconnection can be performed with the default settings, and the wrong custom settings can be corrected.

The second effect is that even when a maintenance console that does not support a high communication speed is used, the connection is temporarily established with the default setting and the connection is changed by changing the custom setting to a communication speed that can be supported. It is possible.

The third effect is that if the main storage device 30 and the non-volatile storage device are constituted by a high-speed memory (generally constituted by a high-speed memory), the RS23 can be transmitted from the maintenance console.
When the two-port communication setting is read, the custom setting information is referred to, so that the data transfer speed is not impaired.

Therefore, by making an incorrect communication setting for the RS232C port, it is possible to recover from a state in which communication has been disabled, and it is not possible to cope with a case where the setting contents are lost or a high communication speed. Even when the maintenance console is used, it is possible to provide a data transmission device capable of reliably performing the RS232C communication.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a data transmission device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the data transmission device shown in FIG.

FIG. 3 is a block diagram conceptually showing a system example of a data transmission device.

FIG. 4 is a diagram showing signal names, pin numbers, and connections when communication according to the RS232C standard is performed on the DTE side.

FIG. 5 is a block diagram illustrating a schematic configuration of an example of a conventional data transmission device.

FIG. 6 is a circuit diagram showing an example of a circuit configuration for automatically identifying a communication speed in the data transmission device.

[Explanation of symbols]

 P RS232C port 26 RS232C cable 27 Maintenance console 29 Central processing unit (CPU) 30 Main storage device (MEM) 30a1 Default setting information 30a2 Custom setting information 31 Nonvolatile storage device (FMEM) 31a Configuration information 31a1 Default setting information 31a2 Custom setting Information 32 local bus 33 communication controller (SPC) 34 input / output register (IOR) 35 data transmission control unit

Claims (6)

[Claims] 1. A data transmission device to which a maintenance console can be connected via an RS232C cable, wherein when the maintenance console is connected via the RS232 cable, communication is performed with an arbitrarily set communication setting. A data transmission device configured to perform communication with default communication settings when the RS232C cable is not connected. 2. A storage means for storing configuration information having storage areas for both default setting information of fixed communication settings and custom setting information of arbitrarily set communication settings. The data transmission device according to claim 1, wherein: 3. The data transmission device according to claim 2, wherein said storage means comprises a main storage device and a non-volatile storage device capable of accessing data via a local bus. 4. An RS232 based on configuration information of the main storage device and the nonvolatile storage device.
A communication controller for performing communication setting of the C port, accessing the main storage device and the non-volatile storage device, and reading and writing configuration information via the local bus is provided. The data transmission device according to claim 3, wherein: 5. The system according to claim 1, wherein said maintenance console is connected to said RS232C port, and comprises an input / output register for storing information as to whether said RS232C port is in a communicable state. 5. The data transmission device according to 4. 6. A data access between the main storage device and the non-volatile storage device via the local bus can be performed based on control by the communication controller and output of the input / output register. The data transmission device according to any one of claims 3 to 5, wherein the data transmission device is configured.