JP2002324013A - Receiving end device for data transfer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiving end device for a data transfer system that, if a transmission abnormality occurs, can immediately acknowledge it. SOLUTION: When receiving one packet's data (S1), the number of the data received is examined (S2). If the number of the data is correct (S2: Yes), the data are stored in a memory (S3), and the processing from S1 to S4 is repeated until the reception of the whole data is finished. If the number of the data is incorrect (S2: No), the transmitting end device is requested to retransmit the same data (S5). When receiving the data retransmitted (S6), in the same manner as in S2, the number of the data is examined (S7). If the number of the data is correct (S7: Yes), the processing shifts to S3. If the number of the data retransmitted is incorrect (S7: No), a reset command is transmitted (S8) to the transmitting end device using a system different from a packet system. After the reset command is transmitted (S8), error processing is executed to terminate this data reception processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving device of a data transfer system for transferring data and size data indicating the length of the data as a group of data.
The present invention relates to a receiving device of a data transfer system capable of immediately recognizing a data reception abnormality.

[0002]

2. Description of the Related Art One of the data transfer methods performed between a computer as a host device and a printer or facsimile device as a peripheral device is a packet method. In this packet system, packet data composed of a header portion indicating a data length and a data portion composed of data itself is transmitted as one data group. When receiving the packet data, the receiving device recognizes the data portion and the break of the packet data based on the data length indicated in the header portion, extracts the data from the recognized data portion, and stores the data in the memory in the device. It performs various processes such as storing in a.

[0003]

As described above, the packet data includes a header portion other than the data in the data group to be transferred. Therefore, even one data is lost or received due to noise or the like. If even one data is received extra (when a reception error occurs), the header part and the data part will be misaligned. If there is a gap between the header part and the data part, the data in the data part will be recognized as the data in the header part, or conversely, the data in the header part will be recognized as the data in the data part. There is a problem that not only the data at the time but also the data after the occurrence of the reception error cannot be normally received.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has as its object to provide a data transfer system receiving side device capable of immediately recognizing when a reception error occurs. And

[0005]

In order to achieve the above object, a receiving apparatus in a data transfer system according to claim 1 comprises: a receiving means for receiving transferred data for each of the group of data; Receiving data comparing means for comparing the number of data of a group of data received by the receiving means with the number of data calculated based on the data length indicated by the size data; and a result of comparison by the receiving data comparing means When the number of data of the received group of data does not match the number of data calculated based on the data length indicated in the size data, a retransmission requesting the transmitting apparatus to retransmit the same data. Requesting means, retransmission data receiving means for receiving retransmitted retransmission data from the transmitting side device based on a retransmission request from the retransmission request means, and retransmission data receiving means Retransmission data comparing means for comparing the number of data of a group of retransmission data received by the above with the number of data calculated based on the data length indicated by the size data, and the retransmission data comparing means As a result of the comparison, if the number of data of the received group of data does not match the number of data calculated based on the data length indicated in the size data, a predetermined signal or command is transmitted to the transfer side apparatus of the data. And transmission means for transmitting the information.

According to the receiving apparatus in the data transfer system according to the first aspect, the transferred data is received by the receiving means for each group of data, and the number of received data and the number of received data are received. The number of data calculated based on the data length indicated in the data size data is compared by the comparing means. As a result of the comparison by the comparing means, if the data numbers of both data do not match, a request to retransmit the same data is made to the transmitting apparatus, and the data number of the received data is compared with the retransmitted data. Is compared with the number of data calculated based on the data length indicated in the size data of the received data, and when the comparison result does not match, the predetermined signal or command is It is transmitted to the device and the occurrence of the reception error is notified to the transfer side device.

[0007] The receiving device in the data transfer system according to the second aspect is the receiving device according to the first aspect,
As a result of the comparison with the retransmission data by the retransmission data comparing means, when the number of data of the received group of data matches the number of data calculated based on the data length indicated in the size data, Storage control means for storing data in the storage means as normal reception data, and when the number of data of retransmission data matches the number of data calculated based on the data length indicated in the size data, the data is returned to normal. The received data is stored in the storage means.

In a third aspect of the present invention, the receiving device in the data transfer system according to the first or second aspect, wherein the transmitting means transmits the predetermined signal or command to the first device. The transmission is performed by a method different from the method.

[0009]

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The present embodiment will be described using a data transfer system including a personal computer (PC) and a multifunction peripheral (MFD). Note that a multi-function peripheral (MFD) is a device having a plurality of functions as a computer peripheral such as a facsimile function, a printer function, and a scanner function.

FIG. 1 is a block diagram showing the electrical configuration of the data transfer system according to the present embodiment. The personal computer 1 includes a CPU 11, a ROM 12, a RAM
13, gate array 14, interface (IF) 1
5, a hard disk drive 16, and a floppy disk drive (FDD) 17. Of these, CPU1
1, the ROM 12, the RAM 13, the gate array 14, and the IF 15 are interconnected by a bus line 18. The bus line 18 includes an address bus, a data bus, a control signal line, and the like.

The CPU 11 stores programs stored in the ROM 12, operating system (OS) and various application programs stored in the hard disk drive 16, and programs supplied via the FDD 17 by a floppy disk. An arithmetic device that operates based on the information, and performs various types of information processing. The ROM 12 is a memory for storing various data in addition to a basic program for operating the CPU 11. R
The AM 13 is a memory for storing various data. Various programs supplied via the FDD 17 by the hard disk device 16 or the floppy disk include:
The program is loaded on the RAM 13 and executed by the CPU 11.

The gate array 14 functions as an interface between the CPU 11, the hard disk device 16, and the FDD 17. The IF 15 is, for example, a bidirectional parallel interface conforming to the IEEE1284 standard. The personal computer 1
It is connected to the multi-function peripheral device 2 via a cable 33 connected to the IF 15 to enable data transmission and reception. Note that the connection between the personal computer 1 and the multi-function peripheral device 2 is not limited to the cable 33, but can be connected by an optical signal such as infrared light.

The hard disk device 16 is a rewritable storage medium for storing an operation system (OS) of the personal computer 1 and various application programs. The FDD 17 is a drive device for reading a program stored in a floppy disk mounted on the FDD 17 and writing a program or data to the floppy disk. The program for the data reception processing in FIG.
6 or a floppy disk.
3 and is executed by the CPU 11.

The multifunctional peripheral device 2 includes a CPU 21, a ROM
22, a RAM 23, an interface (IF) 25, a gate array 26, an operation unit 27, a scanner 28, a printer 29, a floppy disk drive (FDD) 30, and a modem 31. CPU21, ROM
22, RAM23, IF25, and gate array 26
Are interconnected by a bus line 24. This bus line 24 also has an address bus, a data bus, and a bus line, similarly to the bus line 18 of the personal computer 1.
It is composed of a control signal line and the like.

The CPU 21 controls each device connected to the bus line 24 based on various programs stored in the ROM 22 to perform facsimile operations, printer operations, and the like.
Alternatively, it performs a scanner operation or the like. R
The OM 22 is a non-rewritable memory that stores various programs executed by the CPU 21 in the multifunction peripheral device 2. The data reception processing program of FIG.
This is stored in the ROM 22. The RAM 23 is a rewritable memory that stores various data. Facsimile data received from another facsimile machine via the modem 31 or I / O from the personal computer 1
The print data input via the F25 and the scanner data read by the scanner 28 are temporarily stored in the RAM 23.

The gate array 26 functions as an interface between each device connected to the gate array 26 and the CPU 21. IF25 is, for example, I
This is a bidirectional parallel interface conforming to the EEE1284 standard.
3 and connected to the personal computer 1. The operation unit 27 is used by an operator to perform various operations such as setting of the multifunction peripheral device 1.
This is for reading an image of a document inserted in the multifunction peripheral device 2. The printer 29 is for printing facsimile data received by facsimile, scanner data read by the scanner 28, or print data input from the personal computer 1. The modem 31 modulates and demodulates facsimile data for transmission, and transmits and receives various procedural signals for transmission control. The multi-function peripheral device 2 includes the modem 3
1 and a telephone line 32. FDD30
Is a drive device for writing data to a floppy disk mounted on the FDD 30.

Next, with reference to FIG. 2, a data group transferred by the packet method will be described. The data group transferred by the packet method, that is, the packet data 50, includes a header portion 51 and a data portion 52. The header part 51 has a one-byte packet data identifier 53.
And a 2-byte data length 54, for a total of 3 bytes. The packet data identifier 53 is an identifier indicating that subsequent data is packet data,
The data length 54 is size data indicating the size (length) of the data portion 52. Therefore, one packet data 5
The size of 0 is obtained by adding 3 bytes which is the size of the header portion 51 to the size indicated by the data length 54.

The data receiving process in the data transfer system composed of the personal computer 1 and the multifunctional peripheral device 2 will be described with reference to the flowchart of FIG. The process of FIG. 3 is a process executed by the receiving device of the data transfer system to receive a data group transferred by the packet method. Therefore, such data reception processing is executed by the personal computer 1 when the transferred data is received by the personal computer 1, while it is executed by the multifunction peripheral device 2 when the transferred data is received by the multifunction peripheral device 2. Be executed.

In the data receiving process, when one packet of data is received (S1), it is checked whether the number of received data is correct (S2). Specifically, the number of data of a data group actually received as data of one packet,
It is checked whether or not the number of data obtained by adding 3 bytes which is the size of the header portion 51 to the size indicated by the data length 54 of the header portion 51 of the received packet data 50 matches. If they match, the number of received data is correct (S2: Yes), that is, since the data was normally received, the received data is stored in a predetermined memory in the RAMs 13 and 23 (S3). If the reception of all data has been completed (S4: Yes), this process is terminated,
On the other hand, if the reception has not been completed (S4: No), the processing shifts to S1, and the above processing is repeated until the reception of all data is completed (S1 to S4).

As a result of checking the number of received data in the process of S2, if the number of received data does not match the number of data obtained by adding 3 bytes to the size indicated by the data length 54, the number of received data is incorrect. (S2: N
o). That is, since a reception error has occurred, the received group of data is discarded, and a request for retransmission of the same data is made to the transmitting apparatus (S5). After requesting retransmission (S
5) When data for one packet is received again (S
6) The data number of the re-received packet data 50 is checked in the same manner as in S2 (S7). If the number of re-received data is correct (S7: Yes), the process proceeds to S3, and the above-described processes from S1 to S4 are repeated until reception of all data is completed.

If the number of re-received packet data 50 is incorrect (S7: No), it is determined that the receiving error cannot be recovered and a reset command is transmitted to the transmitting device (S8). The reset command sent here is sent to the transmission side device by a method other than the packet method.
This is because, since an error has occurred in the data transfer by the packet method, it is difficult to receive the reset command normally even if the reset command is sent by the same method. By sending a reset command using a method other than the packet method,
The reset command can be more reliably transmitted to the transmitting device.

After transmitting the reset command (S8), the receiving side device performs error processing (S9) and notifies the operator of the occurrence of a receiving error. Specifically, an error is displayed on the display device of the receiving device or a buzzer sounds to notify the operator of the occurrence of the receiving error. After the error processing (S9), the data reception processing ends.

As described above, according to the data transfer system of the present embodiment, the number of data received is checked every time one packet data 50 is received. Or recognize it,
Conversely, the data portion 52 is not erroneously recognized as the header portion 51. Therefore, the header part 51 can be correctly received as a header part, and the data part 52 can be correctly received as a data part. Further, when a reception error occurs, the reset command is transmitted to the transmission side device by a method different from the packet method, so that the occurrence of the reception error can be reliably notified to the transfer side device.

In the receiving apparatus in the data transfer system according to any one of claims 1 to 3, the processing of S1 and S6 is performed by the receiving means and the retransmission data receiving means, and the processing of S2 is performed by the reception data comparing means and the retransmission data comparing means. , S7, and S8 as the transmission means. Further, in the receiving device in the data transfer system according to the second aspect, the processing of S3 corresponds to the storage control means.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the gist of the present invention. Can easily be inferred.

For example, in the present embodiment, the packet method has been described as an example. However, if the method transfers data and size data indicating the data length as a group of data,
It is possible to apply the present invention to a system other than the packet system. Further, the reset command transmitted in the process of S8 is changed to another command such as an error command,
It is also possible to change to a control signal such as a reset signal other than the command. For example, a reset signal may be transmitted by using one of the control terminals (ports) in the parallel interface and switching the terminal voltage from high to low or from low to high. According to this method, it is possible to more reliably notify the transfer-side device that a reception error has occurred in the reception-side device.

[0028]

According to the receiving apparatus in the data transfer system according to the first aspect, every time a group of data is received, the number of received data is compared with the number of data to be received by one. When a reception error occurs in both the data received and the retransmission data for the first time, a predetermined signal or command may be transmitted to the transfer side device to notify the transfer side device of the occurrence of the reception error. There is an effect that can be.

According to the receiving device in the data transfer system of the second aspect, in addition to the effect of the receiving device of the first aspect, if the reception error does not occur in the retransmission data, the retransmission data is returned to normal. Data can be stored in the storage means, and even when one data is received extra (due to abnormal reception) due to noise or the like at the time of receiving the first received data, it can be stored as retransmitted data. This has the effect of greatly reducing the case where communication is interrupted due to noise.

According to the third aspect of the data transfer system of the present invention, in addition to the effects of the first aspect of the present invention, furthermore, the predetermined signal or command sent to the transfer side apparatus is received. Since the transmission is performed by a method different from the transfer method in which the abnormality has occurred, there is an effect that such a predetermined signal or command can be more reliably transmitted to the transfer side device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a data transfer system according to one embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a data structure of packet data.

FIG. 3 is a flowchart illustrating a data reception process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Personal computer (reception side apparatus or transmission side apparatus) 2 Multifunction peripheral apparatus (reception side apparatus or transmission side apparatus) 50 packet data (1 group of data) 51 header part 52 data part (data) 53 packet data identifier 54 data Length (size data)

Continued on front page F term (reference) 5B083 BB03 CC06 CD06 CD07 EE11 GG04 5C075 CA03 CA14 CD25 CE09 FF09 5K034 AA06 AA09 DD01 FF01 FF04 FF13 FF15 FF18 FF19 HH01 HH02 HH09 HH11 MM01 TT02

Claims (3)

[Claims] 1. A receiving device of a data transfer system for transferring data and size data indicating the length of the data as a group of data from a transmitting device, receiving the transferred data for each of the group of data. Receiving data comparing means for comparing the number of data of a group of data received by the receiving means with the number of data calculated based on the data length indicated in the size data; As a result of the comparison by the comparing means, when the number of data of the received group of data does not match the number of data calculated based on the data length indicated in the size data, the same data is transmitted to the transmitting device. Retransmission request means for requesting retransmission, and retransmission data for receiving retransmitted retransmission data from the transmission side apparatus based on a retransmission request from the retransmission request means. Receiving means; retransmission data comparing means for comparing the number of data of the group of retransmission data received by the retransmission data receiving means with the number of data calculated based on the data length indicated in the size data; As a result of the comparison with the retransmission data by the retransmission data comparison means, if the number of data of the received group of data does not match the number of data calculated based on the data length indicated in the size data, the data And a transmission unit for transmitting a predetermined signal or command to the transfer side device. 2. As a result of the comparison of the retransmission data by the retransmission data comparing means, the number of data of the received group of data coincides with the number of data calculated based on the data length indicated in the size data. 2. The receiving device of the data transfer system according to claim 1, further comprising: storage control means for storing the data in the storage means as normal reception data when the data is received. 3. The data transmission method according to claim 1, wherein the transmission unit transmits the predetermined signal or command to the transfer side device by a method different from the data transfer method. The receiving device of the transfer system.