JPH03234132A - Communication system - Google Patents

Abstract

PURPOSE:To attain recommunication even when communication is failed and to preclude the possibility of data missing hy storing information specifying a unit data being an object of transmission at a storage device side, checking the presence of the unit data being the object of transmission based thereon and deleting data in the storage device in the lump when no data exists. CONSTITUTION:Information specifying a unit data of an object of transmission is stored when a data is sent from an IC card reader/write 2 to a computer 1 and the information is revised every time the transmission is confirmed and data stored in a storage device 3 are deleted in the lump when loss of the data being an object of transmission is discriminated based on the information. Thus, When the communication is failed on the transmission of data in plural units, since the data are left in the storage device 3 without delete of the data, the data is sent without any trouble by recommunication.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of communication between two devices, such as a computer and a terminal device.

[Conventional technology]

There is a system in which data stored in a plurality of IC cards is input to a computer and stored in its storage unit. Figure 4 shows the schematic configuration of this system, where 1 is a computer;
1a is a storage section thereof, 1b is a communication control section, and the communication control section 1b has a plurality of IC card readers/writers 2, 2...
The communication control units 2a, 2a, . . . are connected to each other.

IC card 3.3... is IC card reader/writer 2
2... stores data written by the computer 1 or data written by other devices. When transmitting this data to the storage section 1a of the computer 1, the procedure shown in FIG. 5 was used.

In FIG. 5, ■ and 0 represent the relationship between transmission and reception.

When the computer 1 receives a data transmission request from the IC card reader/writer 2, it enters the process shown in FIG. 5 and performs the process to start data collection (Ill).

This is the initialization of the received file, etc. Then the command “
a' is sent to the requested IC card reader/writer 2 (#2). This command "a" is for requesting transmission of one item of data stored in the IC card 3.

The IC card reader/writer 2 receives this command “a” (#11) and checks whether there is data in the IC card 3 attached to the IC card reader/writer 2 (#1).
2) If there is data, send "00" to computer 1 (#13); if not, send "01"(#19). Data to be transmitted is read from the IC card 3 into an appropriate register of the IC card reader/writer 2, and is transmitted from there via the communication control section 2a.

After transmitting the command "a", the computer 1 starts a timer (#3), and if data is received from the IC card reader/writer 2 within the time limit, the content is determined (#4).

If there is no error processing (116), an error message is displayed on the display unit (not shown) of the computer 1 (117). If the received data is “00”, the sent data is accumulated in the received file (
#8), if “01”, close the received file, storage section 1a
Data collection completion processing such as writing to is executed (#5).

When writing to the storage unit 1a is performed, the received file is erased.

On the other hand, when the IC card reader/writer 2 transmits "01", it executes the termination process (+120). “00
”, the transmitted data is erased and the next data is read into the register in the IC card reader/writer 2 (#14).Then wait for the next command a” (#15)
, start the timer (1116), and if there is no next command "a" within the time limit, execute error processing #17
), display an error message (#18).

If command "a" is received within the time limit, the process returns to step #11.

[Problem to be solved by the invention]

In the conventional communication system as described above, data that has been sent unsuccessfully is not stored in the storage unit 1a, and the IC card 3
It will also be erased and cannot be reproduced.

In other words, in IC card reader/writer 2, step #13
This is because after the data is transmitted in ~#14, it is erased regardless of whether the transmission was successful or not.

Furthermore, when the computer 1 side restarts due to error output (#7), it outputs the command "a" and requests the transmission of the next data. Any data that cannot be stored is not stored in the storage unit 1a.

The present invention was made to solve these problems, and by increasing the number of types of commands, in the above example, the data stored in the IC card is erased regardless of whether the communication is successful or not. To provide a communication method that can be stored in a storage unit without any problems, that is, can completely complete transmission and reception of all data even if there is a communication malfunction.

[Means to solve the problem]

In the communication method of the present invention, information identifying the unit data to be transmitted is retained, and this is updated each time the transmission is recognized as R. Based on this information, it is determined that there is no more data to be transmitted. At this point, all data stored in the storage device will be deleted.

[Effect]

Even if a communication failure occurs during the transmission of multiple units of data, the data remains in the storage device without being erased, so it can be transmitted without omission by re-communication.

〔Example〕

The present invention will be described below with reference to an embodiment of the apparatus shown in FIG. Figure 1 shows the communication control unit 1b on the computer 1 side.
FIG. 2 is a flowchart showing the processing procedure of the communication control section 2a of two examples of IC card readers/writers.

FIG. 3 is an explanatory diagram showing the transmission and reception status of command data. In the figure, ■, ■, . . . represent the relationship between transmission and reception.

When the IC card reader/writer 2 requests data transmission, the computer 1 executes data collection start processing (
1131). This processing includes initialization of the received file. Next, the command "S" is sent to the IC card reader/writer 2 that requested the transmission (1132).

Command "S" is a transmission start declaration to the IC card reader/writer 2. The IC card reader/writer 2 that received this (151) checks whether there is any internal abnormality (
152) If there is no command, send command “00” If there is an error, send “01” to computer 1 (15
3.65). Step # when sending command “01”
Return to 51.

After sending the command "S", the computer 1 starts a timer (I33), and if there is no response within the time limit or if "Ol" is received within the time limit, it enters abnormality processing or error processing (+134.I42). Displays a message reporting the error occurrence and prompting a reboot (I43). If "00" is received within the time limit, use the same command as before.
Send to IC card reader/writer 2 (+135)
.

After transmitting "00", the IC card reader/writer 2 sets a flag indicating the number of data stored in the RC card 3 to be transmitted to 1 (I54), starts a timer, and waits for command "a" to be received. (I55). If command "a" is not received within the time limit, the process returns to step #51. When a command is received within the time limit (I56), it is checked whether the command is correct (“a” is sufficient), and whether there is any abnormality in the device, and the data represented by the flag is checked.
First, the presence or absence of data from the first game is checked (I57). “01” if data does not exist, “00” if data exists, “02” if there is an error in the data device
”, if the command is different, that is, if a command other than “a” is received, “03” is output to the computer 1 (#5
B.

66.71.72). For step #71.12 I
The process moves to No. 65 abnormality processing.

On the computer 1 side, after sending the command "a", start the timer (1136), and if there is no response from the IC card reader/writer 2 within the time limit, or if "02" or "03" is received, the timer is activated in lI42. Move to abnormality processing (lI37
).

If "00" and data are received, a command "b" is transmitted (1144). This command "b" is a confirmation of the response after sending the command "a." If the message is not received within the time limit, the process returns to step #51. If this is received within the time limit (I68), the presence or absence of an abnormality is checked (I6
9) If there is no abnormality, send the command "00" similarly to step #53 (I70), and further add 1 to the flag (1700). Here it will be set to 2.

Computer 1 starts the timer after sending command “b” (1145), and if there is no response within the time limit or “01”
(+146), step #4 of abnormality processing
Enter 2. On the other hand, if "00" is received, data accumulation processing is started and data is written to the received file (I
47). Then, return to step ll35 and use the command “a”
Issue again and wait for the next data. In this way, steps #35-37, 44-47 are repeated on the computer, and steps #55-57, 66-47 are repeated on the IC card reader/writer 2.
70. Repeat 700.

For example, if three items of data have been accumulated in the IC card 3, if normal communication is performed and the flag is set to 4, and step 1157 is reached, there is no more data, so step #58 is reached. “01” will be transmitted. Upon receiving this, computer 1 transmits command "C" (1138). Command “C” is a notification to the IC card reader/writer 2 that data collection has been completed,
When IC card reader/writer 2 receives this (I10
) Check whether there is an abnormality (+161), and if there is an abnormality, return to the abnormality processing in step #45. If there is no abnormality, send the command "00" to confirm (I62)
. Then, the data up to the contents of the flag (here 4) are deleted (I63), and a predetermined termination process is performed (164).

When the computer 1 receives the command "00", it starts a timer (1t39), and if it does not receive a response within the time limit or if it receives "01" within the time limit, it enters step #42 of abnormality processing and returns "00'' is received, data collection termination processing such as closing the received file and writing to the storage unit 1a is performed (lI41).

By the way, as shown in Figure 3 with a * mark, data should be sent as "00" (166), and if this communication is not working properly,
The timer (lI36) exceeds the time and abnormal processing (1
142). Also, if "00" becomes "02", "03'", abnormality processing (142) is entered.If "00" becomes "01", the computer will send the command "C", but the IC card reader /The writer 2 side cannot receive the command "b" and enters abnormality processing ($165) as an abnormality in step #69.
Enter 42.

Computer 1 displays an error message (#4
3) This allows the operator to restart.

On the other hand, on the IC card reader/writer 2 side, step #67
When the timer exceeds the time limit, abnormality processing is entered in step 1165, and the process returns to step #51 to wait for command "S". Therefore, by restarting the computer I
Data from the first game of C card 3 will be transmitted. That is, data deletion in step #63 is not performed midway.

Note that the present invention is not limited to the above-described embodiments, but can be applied generally to cases where data stored in a storage device is transmitted from this device to another device.

〔Effect of the invention〕

In the method of the present invention as described above, it is possible to re-communicate even in the event of communication failure, and the excellent effect that there is no risk of data loss can be obtained.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing an example of the processing procedure on the receiving side in the system of the present invention, Fig. 2 is a flowchart on the sending side, Fig. 3 is an explanatory diagram of the data communication of Figs. 1 and 2, and Fig. 4 is FIG. 5 is a block diagram of a device to which the method of the present invention is applied, and is a flowchart showing a conventional processing procedure on the transmitting and receiving side. 1...Computer 1a...Storage unit 1b...
Communication control unit 2...IC card reader/writer 2a
. . . Communication control unit 3 . . IC card In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) 1 from a storage device that stores multiple units of data
In a communication method that transmits data unit by unit to another device, when the other device receives one unit of data, it transmits a confirmation signal to the storage device, and the storage device receives the unit data to be transmitted. Retain information that identifies
Upon receiving the confirmation signal, this information is updated, and based on the retained information, the presence or absence of the unit data to be transmitted is checked, and if the data does not exist, the data in the storage device is deleted all at once. Characteristic communication method.