JPH0738539A - Data transfer method, data transmitter and receiver - Google Patents

Abstract

PURPOSE:To reduce overhead caused by searching a communication enable channel every time with data transfer or waiting time until radio waves to be transmitted get stable in the case of transmission with a simplex communication system using packets. CONSTITUTION:In the case of transmission, a state code SC and a code EC for error detection are added to print data and defined as a packet and the plural packets are continuously transmitted. On the reception side to receive these packets, concerning each packet, it is detected by using the code for error detection whether the data are normally transferred or not. When the presence of any error is judged, code NAK is returned, and the transmission side retransmits the data of the packet where the error is found out. Since it is not necessary to repeatedly search the idle channel for each packet, transfer speed is not decelerated. Further, by increasing/decreasing the size of the packet corresponding to the frequency of error generation, best transfer efficiency can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for wirelessly transferring data, and more specifically to a method of transferring data between computers or between a computer and peripheral devices, and a data transmitter and a data receiver to which this method can be applied. Regarding

[0002]

2. Description of the Related Art Generally, when transferring data between computers or peripheral devices, the two are usually connected by a cable and transferred by wire. With the spread of data, wireless data transfer has been attempted without the need to connect a cable. In addition, there is an increasing demand for sharing high-speed devices such as laser printers among multiple computers so that print data and other data can be processed all at once.Let's avoid complicated wiring and transfer data using radio waves or light. The following are also proposed.

In such data communication by radio (including optical communication as well as radio waves), in order to ensure reliability, data is collected every predetermined number of bytes,
Data for error detection is added to this to make a packet.
Every time the packet is transmitted, the receiving device detects whether there is an error in the transferred data using the error detection data,
This is sent back to the sender.

[0004]

However, in addition to the fact that wireless data transfer is essentially serial communication and it takes time for data transfer, it is further necessary to judge an error by a packet and to send a judgment result. There was a problem that it took time. As a result, the computer is occupied by data transfer for data exchange and printing, the transfer speed is slower than the high-speed page printer, and the expensive high-speed printer cannot be effectively used. There is a problem in that the occupation time of the is also long.

In particular, in the case of data communication by radio waves, a plurality of usable channels are open to the public, and it is common for the transmitting side to select a free channel at the time of starting transmission for communication. This is because, from the viewpoint of publicity of radio waves, it is not allowed for a single transmission device to occupy a specific channel even when it is not used. Even if weak radio waves, infrared rays, far infrared rays, and other wireless means that do not have legal restrictions on occupation time are used, the channel resources for communication cannot be taken infinitely, and multiple computers and peripheral devices cannot be used. At the same time, in order to perform data transfer without causing interference, it is necessary to adopt a design in which one communication device does not occupy a specific channel.

Therefore, when one packet is transmitted,
The transmitting device once releases the right to use the channel. The device on the side of receiving the data now becomes the transmitting side, searches for an empty channel, secures the right to use the channel, and then transmits an acknowledge signal indicating whether the data was normally received or a request for retransmission is made. In response to this signal, the device on the transmission side transmits either a new packet or a previous packet that could not be transmitted normally. Before that, the process of searching and securing an empty channel must be performed again. I won't. For this reason, it is necessary for the transmitting device and the receiving device to perform processing such as searching for and securing an empty channel for transmission of one packet without fail, and waiting for the radio wave to become stable. This has been a cause of further reducing the transmission speed of the transfer. These problems cannot be overlooked particularly in simplex communication in which only a single wireless device is prepared for transmission and reception.

[0007] Of course, if the communication about whether or not the data is normally transmitted is not performed, the data can be continuously transmitted while the channel use right is secured, but then, the reliability of the data transmission can be sufficiently secured. Can not. Also,
If the capacity of data belonging to one packet is increased and the amount of data to be transmitted at one time is increased, the time required for a free channel search will be relatively reduced, but the amount of data to be retransmitted will also increase if an error occurs. , The overall throughput is still reduced. Of course, if the packet size is reduced when the communication state is poor, the probability that an error is included in one packet will decrease, and the packet retransmission rate will also decrease. However, as the number of packets becomes smaller, the number of packets to be transferred will increase, and the overhead due to the waiting time until the search for an empty channel and the wireless output becomes stable will increase. I won't.

A data transfer method, a data transmitter and a receiver of the present invention are intended to solve these problems and improve the speed of data transfer between computers or peripheral devices. I took it.

[0009]

According to the data transfer method of the present invention for transferring data between computers or peripheral devices, the transmitting side includes a plurality of data to be output, to which a plurality of information to which error detection of the data is added is added. The packet is divided into packets, a channel that can transmit the packet by wireless communication is secured, the plurality of packets are continuously output through the secured channel, and the receiving side outputs a plurality of packets through the channel. Are continuously received, data and information regarding error detection are extracted from the received packets, and it is determined whether or not each of the received packets is normally transmitted using the extracted information regarding error detection. The result of the determination is collectively returned to the transmitting side using an empty channel.

The data transmission apparatus of the present invention is applicable to the above-mentioned data transfer method and wirelessly transmits data to a computer or a peripheral device, and outputs the output data as information relating to error detection of the data. Data dividing means for dividing into packets, output means for selecting a free channel from a plurality of channels and wirelessly outputting data using the channels, and receiving the divided packets for each packet A plurality of output control means for continuously outputting by the output means without receiving a completion response from the receiving side, and retransmitting only a packet having an error in data transmission when receiving a response from the receiving side. The gist of the present invention is to have a packet retransmitting means.

On the other hand, the data receiving apparatus of the present invention is applicable to the above-mentioned data transfer method, receives data wirelessly transmitted to a computer or a peripheral device, and receives data via one of a plurality of channels. Receiving means for continuously receiving a plurality of packets transmitted by the receiving means, a data separating means for separating data and information regarding error detection from the received packets for each packet, and the separating means. And an error determination unit that determines whether or not there is an error in the received data for each packet based on the error detection information, and a response unit that returns the result of the determination to the transmission side using an empty channel. Is the gist.

In the data transfer method of the present invention,
It is also possible to adopt a configuration in which the length of the data included in each packet is variable according to the packet transmission / reception status such as the error occurrence frequency. Further, in the data receiving device of the present invention, when the error determining means determines that the received data has an error, the error packet is retransmitted until the error packet is retransmitted. Providing an output suppressing unit that does not output packet data to the outside is also suitable when the receiving device is connected to a device that handles data irreversibly, such as a printing device.

The term "wireless" in the present invention means that it is not a wired system directly connected by a cable, and it is not limited to specific low power communication, but may be specific weak communication or communication using other bands. Optical communication using infrared rays, far infrared rays, microwaves, or the like can also be used.

[0014]

In the data transfer method of the present invention configured as described above, the receiving side divides the data to be output into a plurality of packets to which data relating to error detection of the data is added, and the packets are wirelessly transmitted. A channel that can be transmitted by communication is secured and output wirelessly. The receiving side receives the packet, extracts the data and the information regarding the detection of the error from the packet, and determines whether or not the data is normally transmitted based on the information regarding the error detection. As a result of this determination, a free channel is secured again, and the result is collectively returned to the transmitting side. Therefore, the data is divided into a plurality of packets, but is transmitted continuously at the time of transmission, that is, without vacant channels being secured for each packet, and the reply regarding the presence or absence of an error is also collectively transmitted. As a result, it is possible to reduce the time required for the empty channel search.

On the other hand, the data transmitting apparatus of the present invention can realize the transmitting side of this transfer method, and the data receiving apparatus of the present invention can realize the receiving side of this transfer method. The data transmitting device and the data receiving device are normally used in a pair, but they can also be used individually, for example, by combining the transmitting device of the present invention with a receiving device that does not use information regarding error detection to perform data transfer. Further, in the present invention, the code relating to error detection is
It is also possible to include an error correction code, perform error correction on the reception side, and request the transmission side to retransmit data only when the error cannot be corrected by the error correction code.

[0016]

Preferred embodiments of the present invention will be described below in order to further clarify the structure and operation of the present invention described above. FIG. 1 is a schematic configuration diagram of a data transmission device 1 and a data reception device 5 according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an internal configuration of the data transmission device 1. As shown in the figure, the data transmission device 1 is used by being connected to the printing output of the computer 2, and the data reception device 5 is used.
Is used by connecting to the print input of the printer 6.

As shown in FIG. 1, the data transmission device 1 and the data reception device 5 mainly include a data communication control unit 7, a radio communication control unit 8 and an antenna 9. In this embodiment, since data is sent from the computer 2 to the printer 6 via the data transmission device 1 and the data reception device 5, the data transmission device 1 functions as a master and the data reception device 5 functions as a slave. The data transmitting device 1 and the data receiving device 5 have the same internal configuration, and data can be transferred from the data receiving device 5 to the data transmitting device 1. Also in this embodiment, the data is transmitted from the data receiving device 5 to the data transmitting device 1 in order to notify whether or not the data transmission by the packet is performed without error. The actual data transfer will be described later.

The internal structure of the data transmission device 1 will be described. As shown in FIG. 2, the data transmission device 1 includes an 8-bit microprocessor (hereinafter referred to as MPU) 11,
A SIO 12 for converting data output from the MPU 11 into a serial signal and a transmission / reception unit 14 connected to the SIO 12 are mainly configured. The decoding circuit 22, the transmission / reception unit controller 25, etc. are connected. The data input / output of the memory 27 is also connected to the data bus 16. The MPU 11, the memory controller 20, the IO decoding circuit 22, the transmission / reception unit controller 25, and the memory 27 constitute the data communication control unit 7. Also, SIO
12, the transmission / reception unit 14 constitutes the wireless communication controller 8.

The data transmitting apparatus 1 includes a cable 29,
It is connected to the printing output port 32 of the computer 2 via the connector 30. MPU1 of data transmission device 1
1 is a control signal (strobe ST
RB, reception response AKN, busy BUSY) to receive print data, and using the memory controller 20,
The print data is sequentially stored in the memory 27. When the print data of a predetermined amount or more is stored, the MPU 11 forms this data into a packet and sends it to the SIO 12. At the same time, the transceiver unit controller 25 is controlled to switch the transceiver unit 14 to the transmittable state.

Upon receiving the print data, the SIO 12 converts the print data sent as a parallel signal into a serial signal and outputs the serial signal to the transmission / reception unit 14. The communication method is
Character synchronization (BISYNC synchronization) communication, SIO12
Outputs a data to be communicated with a synchronization character. The transmission / reception unit 14 puts this serial signal on the frequency of the channel assigned in advance and transmits it from the antenna 9 to the outside. In the present embodiment, data is transmitted by the simplex method, the maximum number of channels that can be used by the transmitting / receiving unit 14 is 10, and channel 0 is used as a control channel. In addition, SIO12 and MPU
Data exchange with 11 is performed using the transmission interrupt Tx and the reception interrupt Rx.

The transmission / reception unit 14 conforms to the standard of the radio equipment for data transmission in the 400 MHz band of the specific low power radio station, the communication system is the simplex system, the total number of used channels is 10, and the modulation system is the binary FSK modulation. System, modulation speed is 4
It is 800 bps. The transmission / reception unit 14 in the present embodiment performs carrier sense under the control of the transmission / reception unit controller 25, and performs transmission and reception using a channel in which interference does not occur according to the instruction.

The data receiving device 5 having the same configuration as the data transmitting device 1 receives the packet by the transmitting / receiving unit 14 and outputs it to the MPU 11 via the SIO 12. The MPU 11 receives the reception interrupt Rx and receives the SIO.
12 is accessed, the received data is read, and the data is sequentially stored in the memory 27. After that, the data formed on the memory 27 is output to the printer 6 for printing.

Next, the transmission / reception processing executed by the data transmitting apparatus 1 and the data receiving apparatus 5 will be described with reference to the flowchart of FIG. When print data is sent from the computer 2, the MPU of the data transmitter 1
11 starts the transmission processing routine shown in FIG. 3, and first, the data sent from the computer 2 is stored in the memory 2
The process of storing in 7 is performed (step S120). In this case, the data storage location is sequentially performed from an address previously determined as the print data storage location, and the pointer value indicating the final storage address is incremented by 1 each time the data is stored. Therefore, when the data transmission from the computer 2 continues, the print data is sequentially stored in the memory 27. When the data on the memory 27 is transmitted and becomes unnecessary, the storage start address is incremented. A specific address range is prepared for the data storage location (print data buffer). Within this range, the range where the untransmitted print data is stored is the storage start address and the storage end address. And has been used as a so-called ring buffer.

After the data is stored, the MPU 11 determines whether the stored data is in a packet (step S130). Since data is transmitted in packets and n packets are continuously transmitted, the MPU 11 waits for the memory 27 to store sufficient data to form n packets. If the amount of data is insufficient, nothing is done and the process directly goes to "NEXT" to end this routine once.

When it is determined that sufficient data to form the packet is stored in the memory 27 (step S130), the status code SC indicating the packet status and the error detection code EC are added to this data. Then, a process for forming a packet is performed (step S140). For example,
As shown in FIG. 5, the status code SC and the error detection code EC are added before and after the predetermined number of bytes of data PD1 to form the packet P1. Status code SC
Is a code "CNT" indicating that the packet is continuous after the packet, or a code "E" indicating that the packet is not continuous after the packet.
There is "ND". Various kinds of error detection codes EC are known, but in the present embodiment, the cyclic code CR is used.
C was used.

Next, it is determined whether all the packets P belonging to this transmission have been created (step S150). In the present embodiment, since n packets are continuously transmitted, all the packets belonging to one transmission are generated. Since there is a subsequent packet from the first packet to the (n-1) th packet, its status code is "CNT", and the status code of the last packet is
It becomes "END". FIG. 5 shows how a packet is created in this way. In FIG. 5, n packets transmitted first are shown, and the print data contained in these packets are shown as PD1-1 to PD1-n.
The first half of the subscript indicates which time the packet is transmitted, and the second half indicates the number of the packet in the group.

If all the packets have not been created, the process directly goes to "NEXT" and this routine ends. On the other hand, in this way, when it is determined that n packets are formed for the print data stored in the memory 27, the start address and end address of the data forming the packet,
Also, a table such as a transmission address pointer for this packet is created (step S160). After that, connection processing with the partner station is performed (step S17).
0).

The connection process is performed as follows. The transmission / reception unit 14 of the data transmission device 1 that attempts to transmit data is called a calling station, and the transmission / reception unit 14 of the data reception device 5 that receives data from the calling station is called a called station. An example of the connection procedure is shown in FIG. Figure 6
Is the procedure for simplex system and fixed / manual channel switching. As shown in the figure, the calling station searches for an empty data channel, confirms that the control channel is empty, and then makes a call using the control channel. The connection request signal including the specified empty data channel designation information is transmitted. Upon receiving the control signal, the called station confirms that the control channel is free, and then returns a connection response signal using the control channel, whereby the line is connected to the designated channel. After the connection with the partner station is performed, the transmission interrupt mask is released to accept the transmission request (step S180),
This routine is ended by exiting to "NEXT".

When the above processing is performed and the packet preparation and line connection are performed, the transmission interrupt mask is also released, so that the MPU 11 receives the transmission interrupt Tx from the SIO 12 and is shown in FIG. Execute the transmission interrupt processing routine.
In this interrupt processing, first, it is determined whether or not there is transmission data remaining (step S200), and if transmission of all data of that packet is completed, it is determined whether or not there is an untransmitted packet. , (Step S210), if transmission of all the packets is completed, processing for disconnecting the line is performed (step S215), and then the process directly returns to end this routine once.

When the transmission data remains, a process of reading 1-byte data from the memory 27 is performed by referring to the transmission address pointer (step S220).
When 1 byte of data is read, the above-mentioned address pointer is automatically incremented, and the MPU 11 prepares for the next transmission interrupt Tx. The data read from the memory 27 is output to the SIO 12 (step S23
0), the transmission / reception unit 14 transmits the data to the data reception device 5 via a predetermined channel.

When a large amount of print data is sent from the computer 2 by repeating the above processing, MP
The U11 divides this data into a predetermined length and forms this into a packet, which is sequentially processed by the SIO 12 and the transmission / reception unit 1.
4 to the data receiving device 5.

The transmission of data by the transmission / reception unit 14 is 400M as shown as "communication" in FIG.
There is a limit of 40 seconds or less in the Hz band. this is,
Since the frequency band used in this embodiment is open, a transmission / reception unit 14 limits the time during which it can occupy one channel, and provides an opportunity for another radio station to use the channel. I am giving.
The pause time of transmission is defined to be 2 seconds or more, and if another wireless station does not use this channel during this period, the next communication can be started. As a result, the data transmission device 1
Between the data receiving device 5 and the data receiving device 5, as shown in FIG.
Communication is performed by repeating a section A in which communication is performed (maximum 40 seconds) and a section B in which communication is not performed (minimum 2 seconds). The data per packet is 256 or 512 bytes, and the number of packets transmitted at one time is about 10. Therefore, in this embodiment, one transmission is completed within 40 seconds.

Next, the receiving process by the data receiving device 5 will be described. Transmission / reception unit 1 of data receiving device 5
4 receives the data via a predetermined channel and SI
When O12 outputs the reception interrupt Rx to MPU11, MP
U11 activates an interrupt process and executes a predetermined reception process. Here, for convenience of understanding, the reception process will be described using the flowchart of FIG. 9 described as a sequential process instead of the interrupt process.

When the reception process is started, first, in order to count the number of packets, a process of substituting the initial value 1 for the variable x is performed (step S300). Next, a process of receiving one packet of data is performed (step S31).
0), CRC of print data PD included in this packet
Is calculated and compared with the error detection code EC added at the end (step S320).

If they are the same as each other, it is determined that there is no error in the received data, and the received response signal sequence to be returned is ACKed.
x is set (step S330), and if they do not match, NAKx is set in the reception response signal sequence (step S340), and a value 1 is set in the initial value 0 flag Fng (step S340). Step S345).
FIG. 5 shows the state of data transfer when there is no error in the data of all received packets, while FIG. 10 shows the state of transfer when there is an error. Hereinafter, description will be given while comparing both figures.

When it is determined that the data contained in the packet has no error, a code A indicating that there is no error
After adding CKx to the reception response signal sequence (step S33
0), and the value of the flag Fng is determined (step S35).
0), if the value of the flag Fng is 0, that is, if there is no erroneous packet before that, the print data belonging to the packet is set to be outputable (step S355). Therefore, if there is no error in the print data that is received sequentially (packet 1 in FIG.
-1 to 1-n), these data are set to be outputable, and are sequentially output to the printer 6. on the other hand,
As shown in FIG. 10, when it is determined that the packet 2-x has an error, the packets up to the packet immediately before the packet that is determined to have an error are printed out. , The output of print data is suspended even if an error-free packet is received.

After the reception of one packet is completed and the error is judged using the error detection code EC, the variable x is incremented by 1 (step S360) to judge whether the reception of all the packets is completed (step S360). Step S3
70). If the reception of the data for all the packets has not been completed, the process returns to step S310 and the process is executed again from the reception of the data.

If the receiving process for all the packets is completed, the transmitting side disconnects the line once. Therefore, this time, a process of connecting the line is performed on the receiving side (step S38).
0). The process for connecting the line is similar to that described in the transmission process routine of FIG. 3, and after searching for an empty data channel or the like, the empty channel is designated using the control channel, and the data transmitting apparatus 1 is instructed. The data receiving device 5 is ready to send data. After that, the data receiving device 5 performs a process of returning a reception response signal regarding the transmission data to the data transmitting device 1 (step S390). The reception response signal is composed of a code ACKx or NAKx indicating whether or not there is an error in each packet. After these processes, the line is disconnected, the process goes to "END", and this reception process routine ends.

The receiving process of the data transmitting apparatus 1 when receiving the reception response signal from the data receiving apparatus 5 will be described with reference to FIG. When the line is connected as the receiving device in response to the request from the data receiving device 5, the data transmitting device 1 executes the reply receiving routine shown in FIG. First, a process of receiving the reception response signal sent from the data receiving device 5 is performed (step S400), and the codes included in the reception response signal sequence are sequentially checked (step S410). If this code is ACK, a process of releasing the area of the corresponding print data PD is performed (step S420).

As shown in FIG. 5, when all packets belonging to one group are normally received, all AC
Since the K code is returned, the area where the print data PD1-1 to 1-n forming the corresponding packet was released is released. As a result, the area in which these print data are stored becomes empty and can be subsequently used as a storage area for print data sent from the computer 2.

On the other hand, when the code NAK is present in the reception response signal, the release of the area in which the corresponding print data exists is suspended (step S430), and the print data in this area is sent to the head of the group to be transmitted next. Is added (step S440). In the case shown in FIG. 10, since an error was found in packet 2-x, NAK2-x
Is transmitted, and the corresponding print data PD2-n is left as it is, and this constitutes the head packet of the next transmission group. Therefore, the print data PD2-x and the following data can be printed out only after the next plurality of packets are normally transmitted, and the data transmission device 1 receives the reception response signal from the data reception device 5 that has normally received the data. Releases the print data area. If there are two or more consecutive data transmission errors due to a packet, a routine (not shown) is executed to reduce the size of the packet. Further, when there is no error in the transmission of n packets for two or more times in succession, the processing for increasing the packet size is performed by a routine not shown.

According to the data transfer method of the present embodiment described above, although the simplex method is adopted, a plurality of packets are collectively transmitted and then the reception response signals thereof are collectively received, and an error is detected. Only the packet is retransmitted. Therefore, it is not necessary to send a signal from the receiving side to the transmitting side as to whether the packet is normally transmitted or a request for resending is made for each packet transmission, and in particular, the time required for communication such as search for a free channel and designation of a free channel is omitted be able to. As a result, the overhead required for data transfer can be reduced, and the time required to exchange a predetermined number of bytes of data can be greatly reduced. Moreover, when an error is detected, it is only necessary to retransmit the packet in error, and since this packet is also transmitted collectively in the next transmission group instead of individually, an error occurs. The transfer speed will not be reduced so much.

Similarly, the data transmission device 1 and the data reception device 5 of this embodiment can efficiently perform data transmission and data reception. In the data transmission device 1, even if an erroneous packet exists in a group (plurality of packets) transmitted at a time, the print data of the packet having no error can be sequentially released in the data area. It can be sequentially used for storing print data from the computer 2. Further, in the data receiving device 5, the output of the print data of the packets after the packet in which the error is found is also suspended, so that the order of the data is retained. Therefore, it is suitable for irreversible processing such as printing. Also,
If the frequency of error occurrence is high, increase the length of the data included in the packet, and if the frequency of error occurrence is low,
The data length is shortened. In the former case, the ratio of the status code and error detection code included in the transferred data can be reduced, and in the latter case, the amount of data to be retransmitted can be reduced. As a result, in any case,
The transfer efficiency can be improved.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention. Is. For example, if the number of packets to be transmitted each time is determined in advance, "CNT" or "EN"
Data can be transferred without adding a status code such as "D". It also detects the frequency of error occurrences in packet transmission, and if the frequency of error occurrences is high, shortens the length of the data contained in the packet to prevent the transfer efficiency from being reduced due to data retransmission due to the occurrence of error. It can also be configured to. Furthermore, it is possible to add an error correction code instead of the error detection code. In this case, it is not necessary to request data retransmission for the error-correctable range.

In addition, a configuration using a band of 1.2 GHz or 2.4 GHz for the transmission frequency of the transmission / reception unit 14, a configuration applied to communication between computers, a LAN (local network) including a plurality of computers and printers The configuration and the like applied to can be considered.
Further, the data transmission device of the present invention is usually used in combination with the data reception device of the present invention.
With the configuration in which the code “D” is added, it is possible to receive a plurality of packets by a data receiving device that cannot continuously receive the packets.

[0046]

As described above, the data transfer method of the present invention has an excellent effect that data can be transferred wirelessly at high speed between computers or a peripheral device such as a printer. Therefore, each device such as a computer can be freely arranged. In addition, since the data transferred in parallel is in units of packets, there is an advantage that the time required to retransmit the data when an error occurs can be shortened.

The data transmitting device and the data receiving device using this data transfer method can be realized with an extremely simple structure, and high-speed data transmission and reception can be realized respectively.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a data transmission device 1 and a data reception device 5 according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of the data transmission device 1.

FIG. 3 is a flowchart showing a transmission processing routine performed by the data transmission device 1.

FIG. 4 is an explanatory diagram showing a configuration example of a packet.

FIG. 5 is an explanatory diagram showing a normal transfer state of data in units of packets.

FIG. 6 is an explanatory diagram showing an overall control up to data communication between two wireless stations.

FIG. 7 is a flowchart showing a transmission interrupt processing routine in the data transmission device 1.

FIG. 8 is an explanatory diagram showing a relationship between data communication and a transmission suspension period between wireless stations.

9 is a flowchart equivalently showing a reception processing routine executed by the data receiving device 5. FIG.

FIG. 10 is an explanatory diagram showing a state of transfer when a data error occurs in units of packets.

FIG. 11 is a flowchart showing a processing routine in which the data transmission device 1 receives a reception response signal from the data reception device 5.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Data transmission device 2 ... Computer 5 ... Data reception device 6 ... Printer 7 ... Data communication control part 8 ... Wireless communication control part 9 ... Antenna 11 ... MPU (microprocessor) 12 ... SIO 14 ... Transmission / reception unit 16 ... Data bus 17 ... Address bus 20 ... Memory controller 22 ... IO decoding circuit 25 ... Transmission / reception unit controller 27 ... Memory 29 ... Cable 30 ... Connector 32 ... Printing output port

Claims (5)

[Claims] 1. A data transfer method for wirelessly transferring data between computers or with peripheral devices, wherein the transmitting side divides output data into a plurality of packets to which information regarding error detection of the data is added. Then, a channel that can transmit the packet by wireless communication is secured, the plurality of packets are continuously output through the secured channel, and the receiving side continuously outputs the plurality of packets through the channel. Data and information about error detection are extracted from the received packet, and it is determined whether or not each of the received packets is normally transmitted using the extracted information about error detection. The data transfer method is characterized in that the result of (1) is collectively returned to the transmitting side using an empty channel. 2. A data transmission device for wirelessly transmitting data to a computer or a peripheral device, the data dividing device dividing data to be output into packets to which information regarding error detection of the data is added, and a plurality of channels. An output means for wirelessly outputting data using the channel and a plurality of the divided packets without receiving a reception completion response for each packet from the receiving side. And a packet retransmitting unit that retransmits only a packet having an error in data transmission when receiving a response from the receiving side. 3. A data receiving device for receiving data wirelessly transmitted to a computer or a peripheral device, the receiving means capable of continuously receiving a plurality of packets transmitted via one of a plurality of channels. And a data separating unit that separates data and information related to error detection from the received packet for each packet, and the presence or absence of an error in the received data based on the separated information related to error detection. A data receiving apparatus comprising: an error determining unit that determines each packet; and a response unit that returns the result of the determination to a transmitting side using an empty channel. 4. The data receiving apparatus according to claim 3, wherein when the error determining means determines that the received data has an error, the error is received until the packet in error is retransmitted. A data receiving device comprising an output suppressing unit that does not output the data of packets subsequent to the packet having the error. 5. The data transfer method according to claim 1, wherein when the transmitting side determines that there is a transmission error based on the determination result returned from the receiving side, a packet to be transmitted next is transmitted. A data transfer method that reduces the amount of data contained and increases the data contained in the packet to be transmitted next when it is determined that the transmission has been normally performed for a predetermined period.