JPH07321789A - Radio data communication equipment - Google Patents

Abstract

PURPOSE:To reduce the traffic in radio communication to the utmost even under an environment where the traffic of radio communication is increased by comparing the traffic measured by a traffic measurement means with a preset threshold value so as to decide whether or not the transmission is to be implemented immediately prior to transmission of communication data. CONSTITUTION:A program to be operated as a radio slave station of a conventional radio POS system and also a radio traffic calculation program or the like are set in advance in a ROM 42 of each radio slave station 4a in the radio POS system. Every time the transmission request of communication data is received from a POS terminal equipment 1a, the traffic per unit time is compared with a traffic limit preset in a limit memory and whether or not the traffic limit is exceeds is decided. When it is discriminated that the traffic exceeds a limit, the communication data are tentatively stored in a communication data storage section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless data communication device used as a wireless station connected to a POS terminal or a host computer of a wireless POS (point of sale information management) system.

[0002]

2. Description of the Related Art FIG. 7 is a schematic configuration diagram of a conventional general wireless POS system. The wireless POS system shown in this figure has six POS terminals 1 for registering product sales data.
Two wireless base stations 3 are provided in the host computer 2 as a host device for controlling a, 1b, 1c, 1d, 1e, 1f.
a and 3b are connected by wire, and each POS terminal 1a-
1f are wireless slave stations 4a, 4b, 4c, 4d, 4 respectively.
e and 4f are provided and wireless communication is performed between the wireless base stations 3a and 3b and the wireless slave stations 4a to 4f.
This enables data transmission / reception between the S terminals 1a to 1f and the host computer 2.

Incidentally, the respective POS terminals 1a to 1f are distributed and installed in respective sales floors on one floor of a store, and the respective wireless slave stations 4a to 4f are mounted near the corresponding POS terminals 1a to 1f. Has been. On the other hand, the host computer 2 is installed in a store office,
As it is, wireless communication with each of the wireless slave stations 4a to 4f cannot be performed. Therefore, two wireless base stations 3a and 3b are connected to each PO.
By mounting the S terminals 1a to 1f on the ceiling of the floor where the S terminals are installed, the wireless communication can be performed on the entire floor.

Here, the POS terminals 1a to 1a are placed within the range of the radio wave propagation distance where one of the radio base stations 3a can stably communicate.
c is installed, and within the range of the radio wave propagation distance where the other radio base station 3b can communicate stably, the POS terminal 1d
1 to 1f are installed, each POS terminal 1a to 1c normally communicates wirelessly with one wireless base station 3a, and the remaining POS terminals 1d to 1f have the other wireless base station 3a.
b, the wireless parameters such as the identifier of the communication partner are set to the respective wireless base stations 3a and 3b and the respective wireless slave stations 4 so as to perform wireless communication with b.
Pre-set a to 4f to set up the system.

By the way, as a wireless communication system of such a system, generally, there is a system in which a master controls transmission of a slave between a master wireless station and a slave wireless station, a so-called polling / selecting system. , A method in which each wireless station freely transmits and only one station acquires the transmission right according to certain rules such as "first come, first served",
Although there is a so-called contention method, in the case of a POS system, a high-speed response is often used because a high-speed response is required for a unit price inquiry or the like.

[0006]

However, when the contention method is adopted as the communication method of the wireless POS system, in an environment where the traffic volume of wireless communication increases, for example, in a store having a large sales floor, etc. Like P
If the number of OS terminals is large, the number of transmission retries increases due to the deterioration of the wireless environment, or the frequency of sales registration significantly increases due to busy stores, it takes time to acquire the transmission right. Since there is a high possibility, there was a concern that the response time to a unit price inquiry would significantly increase.

Generally, in the contention system,
CSMA (Carrier Sense Multiple Access) to avoid communication collision by determining whether there is a radio wave carrier before transmission
The method is the mainstream, but when the traffic volume increases, the number of collisions increases, communication may not work, and there is a concern that the system will not function properly.

The present invention has been made under such circumstances, and an object thereof is to increase the traffic volume of wireless communication in a wireless data communication system adopting a contention system as a wireless communication system. Even in an environment, the amount of wireless communication traffic can be reduced as much as possible, the response time for data transmission that requires a response can be reliably shortened, and system down due to a significant increase in traffic volume can be prevented. The present invention aims to provide a wireless data communication device capable of always performing stable data communication.

[0009]

According to the present invention, during transmission processing of communication data, it is judged by another device whether or not the wireless line is in use, and when it is not in use, the transmission right is acquired and the communication data is wirelessly transmitted. In the wireless data communication device for transmitting, the traffic amount measuring means for measuring the traffic amount per unit time of the wireless line and the traffic amount measured by the traffic amount measuring means prior to the transmission process of the communication data are preset. A data transmission judging means for judging whether or not the transmission is to be carried out immediately by comparing with a threshold value, and the communication data is sent when the traffic quantity is equal to or less than the threshold value and the transmission is immediately carried out When the traffic volume exceeds the threshold value and the transmission delay is determined by the communication data transmission processing means for processing and the determination means, the communication data is processed. Communication data storage means for temporarily storing the data, and deferred data transmission means for transmitting the communication data stored in the communication data storage portion by the storage means when the traffic amount satisfies a communicable condition of a threshold value or less. Be prepared.

The data transmission judging means has a judging means for judging whether or not the communication data can be postponed depending on the type of the communication data, and judges whether or not only the communication data which can be postponed is immediately transmitted based on the traffic amount. However, it is preferable that the communication data that cannot be postponed is immediately transmitted regardless of the traffic volume.

[0011]

According to the present invention having such a configuration, prior to transmitting the communication data, the traffic amount measured by the traffic amount measuring means is compared with a preset threshold value and the transmission is immediately performed. It is determined whether or not.
Then, when the traffic amount is equal to or less than the threshold value and it is decided to immediately perform the transmission, the communication data is subjected to the transmission processing. That is, it is determined by another device whether or not the wireless line is in use, and when it is not in use, the transmission right is obtained and the communication data is wirelessly transmitted. On the other hand, when the traffic amount exceeds the threshold value and the transmission delay is determined, the communication data is temporarily stored in the communication data storage unit. Then, the communication data stored in this storage unit is subjected to a transmission process when the traffic volume decreases and the communication enable condition below the threshold value is satisfied.

Therefore, when the traffic volume increases to exceed the threshold value, the transmission of communication data is postponed until the traffic volume decreases and the communicable condition is satisfied. Growth is prevented.

Further, it is judged whether or not the delay is possible depending on the type of the communication data, and the communication processing which cannot be delayed, for example, the data for which a high speed response is required, is immediately transmitted regardless of the traffic volume.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wireless POS system (two wireless base stations 3a and 3b, terminals 1a to 1f) shown in FIG.
Also, an embodiment applied to each of the wireless slave stations 4a to 4f in a system including six wireless slave stations 4a to 4f) will be described with reference to the drawings.

The wireless communication specifications in this embodiment are as follows: radio wave format = spread spectrum, frequency band = 2.4G
Hz band, output = 10 mW / MHz, frequency channel = 1 wave (ch1), communication method = semi-duplex, spreading method = direct spreading method, data communication speed = 256 kbps.

FIG. 1 is a block diagram showing the main configuration of the host computer 2.
Is a CPU (Central Processor) that constitutes the control unit main body.
Unit) 21, a ROM (Read Only Memo) for storing fixed data such as program data executed by the CPU 21.
ry) 22, RAM (Random Acc) that stores variable data
ess Memory) 23, a communication interface 24 to which the wireless base stations 3a and 3b are connected by wire, a keyboard interface 25 for inputting a key signal from a keyboard 25a,
The CRT display device 26a includes a display device interface 26 that sends display data to the CRT display device 26a.

FIG. 2 is a block diagram showing the main configuration of the POS terminal 1a. The POS terminal 1a is a CPU 1
1, a ROM 12 and a RAM 13, a communication interface 14 to which a corresponding wireless slave station 4a is connected by wire, a keyboard interface 15 to which a key signal is input from a keyboard 15a, a receipt / journal printer, a display, a scanner, a card reader, etc. The peripheral device interface 16 is connected to the peripheral device 16a.

Since the other POS terminals 1b to 1f have the same configuration as that shown in FIG. 2, the following description will be given by using the same reference numerals for common portions.

FIG. 3 is a block diagram showing a main configuration of the wireless slave station 4a. The wireless slave station 4a includes a CPU 41 and an RO.
In addition to M42 and RAM43, a timer controller 44 that supplies a timer interrupt signal to the CPU41 at regular intervals,
It is composed of a communication interface 45 to which the corresponding POS terminal 1a is connected, a wireless circuit unit 46 for transmitting and receiving wireless data, an antenna 47, and the like.

The radio circuit unit 46 supplies the communication data generated by the control of the CPU 41 to the modulation unit 46b, and the communication data supplied from the radio transmission unit 46a is modulated and supplied to the antenna 47. Modulator 46
b, a demodulation unit 46c that demodulates communication data received by the antenna 47, a wireless reception unit 46d that takes in the communication data demodulated by the demodulation unit 46, and a radio wave from the communication data demodulated by the demodulation unit 46c. It is configured by a carrier sense unit 46e or the like that determines the presence or absence of carriers.

Since the other wireless slave stations 4b to 4f have the same structure as that shown in FIG. 3, the following description will be given by using the same reference numerals for common portions.

Now, the ROM 42 of each wireless slave station 4a-4f
In addition to the program for operating as a wireless slave station of a normal wireless POS system, particularly, as shown in FIG. 4, a wireless traffic calculation program 51, a data communication determination program 52, and a postponed data transmission program 5
3 and 3 are incorporated in advance.

The wireless traffic calculation program 51
Is a business program for periodically calculating the traffic of wireless communication defined as the usage rate of the wireless circuit per unit time, and this wireless traffic calculation program 51
A traffic amount measuring means is constituted by the ROM 42 storing the above and the CPU 41 executing this wireless traffic calculation program 51.

The data communication judgment program 52 compares the traffic amount measured by the traffic amount measuring means with a preset threshold value before transmitting the communication data, and immediately transmits the data. If the traffic volume is below the threshold value and it is decided to perform transmission immediately, the communication data is processed for transmission, and the traffic volume exceeds the threshold value and a relatively large amount of postponed transmission is determined. Then, the ROM 42, which is a business program for temporarily storing the communication data in the communication data storage unit, stores the data communication determination program 52.
And a CP that executes this data communication determination program 52
The U41 constitutes a data transmission determination means, a communication data transmission processing means, and a communication data storage means.

The postponement data transmission program 53 is a business program for transmitting the communication data stored in the communication data storage unit by the communication data storage means when the traffic volume satisfies the communicable condition of the threshold value or less. Therefore, the ROM 42 storing the postponement data transmission program 53 and the postponement data transmission program 53
The deferred data transmission unit is configured by the CPU 41 that executes

Further, the RAM 43 of each of the wireless slave stations 4a-4f.
In particular, as shown in FIG. 5, a communication data storage file 61 that constitutes the communication data storage unit, a timer interrupt counter 62 that counts the number t of interrupt signal inputs from the timer controller 44, and a carrier sense unit. A radio busy counter 63 that counts the number of times TW that the radio line is in use by 46e, a limit value memory 64 that stores a traffic limit value TR0 as a threshold value of the traffic volume, and the traffic A permissible value memory 65 for storing a traffic permissible value TR1 which is the maximum value of a region which is equal to or less than the limit value TR0 and satisfies the communication enable condition, and a calculation for storing the latest traffic calculated value TR calculated by the wireless traffic measuring means. A value memory 66,
A communication data table 67 that stores each data of the communication data name and the priority flag is formed corresponding to the type code that distinguishes various communication data.

The communication data storage file 61 is composed of a communication data area 61 capable of storing a plurality of communication data and a data number counter 61b for counting the number S of data stored in the communication data area 61a.

The priority flag in the communication data table 67 is a flag for setting whether or not the corresponding communication data can be postponed by the data transmission judging means, and "0" indicates that it can be postponed. , "1" indicates that the postponement is impossible.

The CPU 41 checks the priority flag while executing the data communication determination program 52 to determine whether or not the postponement is possible. Here, the data transmission determination means constituted by the ROM 42 storing the data communication determination program 52 and the CPU 41 executing the data communication determination program 52 determines whether or not it is possible to postpone depending on the type of communication data. Including means.

Next, P of the present embodiment constructed as described above
The operation when the wireless slave stations 4a to 4f wirelessly transmit in the OS system will be described with reference to the flowcharts shown in FIGS.

FIG. 6A is a flow chart showing the main part of the wireless traffic calculation program 51, and FIG. 6B is a flow chart showing the main part of the data communication determination program 52.
(C) is a flowchart showing a main part of the postponed data transmission program.

First, as an initial condition, each wireless slave station 4a
~ 4f communication data storage file 6 of RAM43
1 and the calculated value memory 66 are cleared. The count values t and Tw of the timer interrupt counter 62 and the wireless busy counter 63 are both reset to "0".

Further, for example, "0.7" is preset as the traffic limit value TR0 in the limit value memory 64, and "0.5" is preset as the traffic allowable value TR1 in the allowance value memory 65. ing.

The traffic limit value TR0 and the traffic allowable value TR1 are not limited to those in the present embodiment.
The optimum value should be set within the practical range. However, in general, once the traffic amount increases once, it often takes time to recover. Therefore, it is desirable to have a hysteresis characteristic so that TR1 <TR0.

Further, in the communication data table 67, a data name and a priority flag "0" or "1" are set corresponding to the data types of various communication data. In the present embodiment, only communication data generated in the product sales data registration work performed by the POS terminals 1a to 1f is illustrated, and the unit price inquiry data and the credit collation data, which require a high-speed response, are prioritized as data that cannot be postponed. The description will be continued on the assumption that the flag is set to "1", and the product sales data, the total sales data, the credit sales data, etc. for which no other response is required are postponed data and the priority flag is reset to "0".

By the way, the unit price inquiry data is stored in the POS terminal 1.
When the product code of the customer-purchased product is input in a to 1f, it is data for inquiring the unit price of the product to the host computer 2, and the unit price data of the corresponding product is returned from the host computer 2 in response to this inquiry. To be done. The credit verification data is data for inquiring the host computer 2 about the validity of the credit card when the credit card of the credit customer is read by the POS terminals 1a to 1f. The computer 2 responds that the credit card is valid or invalid.

On the other hand, the product sales data is the POS terminal 1a.
~ The code of the customer purchase product registered in 1f, the number of sales,
The sales total data is data for notifying the host computer 2, and the total sales data is for notifying the host computer 2 of the total points, total amount, etc. of all the purchased products of one shopper registered at the POS terminals 1a to 1f. Data to
The credit sales data is data for notifying the host computer 2 of the contents of the transaction for which payment was made by a credit card at the POS terminals 1a to 1f, and the host computer 2 sends these data. No response.

The timer controller 44 is a CPU
The interrupt interval of the interrupt signal input to the interrupt terminal p of 41 is set to, for example, 50 μs, and the interrupt interval of the interrupt signal input to the interrupt terminal q is set to, for example, 1 s.

Here, the interruption interval of the interruption signal inputted to the interruption terminal p is the radio traffic calculation program 51.
Is executed, and the interrupt interval of the interrupt signal input to the interrupt terminal q is the interval at which the postponed data transmission program 53 is executed.

The interrupt intervals of these interrupt signals are not limited to those in this embodiment, but it is said that the shorter the interrupt interval of the interrupt signal input to the interrupt terminal p, the higher the accuracy. It's ridiculous. However, it is preferably selected according to the performance of the CPU 41.

The CPU 41 executes the processing shown in FIG. 6A in accordance with the wireless traffic calculation program 51 every time an interrupt signal is input to the interrupt terminal p.

That is, first, as ST (step) 1, the timer interrupt counter 62 is incremented by "+1". Next, in ST2, the wireless circuit unit 46 is operated to perform carrier sense, and if it is confirmed that the radio wave carrier is detected by the carrier sense unit 46e, it means that the wireless line is in use, so the wireless busy counter 63 is set in ST3. "+1" count up. If it is confirmed in ST2 that the radio wave carrier is not detected by the carrier sensing unit 46e, the wireless line is not in use.
The process of T3 is not performed.

Next, as ST4, the timer interrupt counter 6
It is determined whether the count value t of 2 has reached the value t0 corresponding to the unit time for measuring the traffic volume. And
If the count value t has not reached the value t0, the current process is terminated. Here, assuming that the unit time is 1 second, the value t0 is "20000".

When the count value t reaches the value t0 in ST4, the timer interrupt counter 6 corresponding to the unit time of the count value TW of the wireless busy counter 63 is set in ST5.
The traffic amount TR per unit time is calculated by dividing by the count value t0 of 2, and the contents of the calculated value memory 66 are updated. Thereafter, if the count values t and TW of the timer interrupt counter 62 and the wireless busy counter 63 are reset to "0" at ST6, the current process is terminated.

Therefore, by the processing of ST1 to ST3, 5
The carrier sense state determined by the carrier sense unit 46e is observed at intervals of 0 μs, and the number of times when the wireless line is in use is counted by the wireless busy counter 63. Then, when the processing time of 1 second is detected by the processing of ST4, the ratio of the wireless usage time per unit time, that is, the traffic volume per second of the unit time is measured by the processing of ST5, and the calculated value memory Written in 66 and updated. After that, the count values t and TW of the timer interrupt counter 62 and the wireless busy counter 63 are reset to "0" by the process of ST6, and the next traffic amount per unit time is measured.

On the other hand, the CPU 41 of each wireless slave station 4a-4f
Is a POS connected through the communication interface 45
Each time a transmission request for communication data is received from the terminals 1a to 1f, the data communication determination program 52 is executed in accordance with FIG.
The process shown in (b) is executed.

That is, first, at ST11, the latest traffic amount TR stored in the calculated value memory 66 per second per unit time is compared with the traffic limit value TR0 preset in the limit value memory 64 to compare the traffic amount. It is determined whether TR exceeds the traffic limit value TR0.

If it does not exceed, it is recognized that communication is possible, and the data transmission process by the contention method is executed in ST12. That is, the wireless circuit unit 46 performs carrier sense to determine whether or not the wireless line is in use. When the wireless line is not in use, the transmission right is acquired and the corresponding communication data is wirelessly transmitted. After the transmission, this processing is ended.

On the other hand, when the traffic volume TR exceeds the traffic limit value TR0, it is recognized that the communication is difficult and the communication data table 6 is designated as ST13.
7, the priority flag corresponding to the type code of the communication data requested to be transmitted is read. Then, if the priority flag is set to "1" in ST14, the communication data requested to be transmitted is the data that cannot be postponed, so that the process proceeds to ST12 and the data transmission process by the contention method is executed.

On the other hand, if the priority flag corresponding to the type code of the communication data is reset to "0" in ST14, the communication data requested to be transmitted is postponable data, so the communication data is stored in ST15. File 6
The communication data is registered in the empty area of the communication data area 61a in No. 1. If the data number counter 61b in the communication data storage file 61 is incremented by "+1" in ST16, the current process is terminated.

Therefore, when the traffic amount TR per unit time does not reach the traffic limit value TR0 by the processing of ST11 and ST12, and there is a request for transmission of communication data, the wireless slave station acquires the transmission right. If the wireless line is not in use and the transmission right is acquired, the wireless transmission is performed.

On the other hand, ST11, ST13 and ST
If the communication data transmission request is made when the traffic amount TR per unit time reaches the traffic limit value TR0 by the processing of 14, it is judged whether or not the communication data can be postponed. Then, in the case of communication of data that cannot be postponed, such as unit price inquiry data and credit collation data, the process waits until the wireless slave station acquires the transmission right by the process of ST12, and if acquired, it is wirelessly transmitted. .

On the other hand, product sales data, total sales data,
In the case of communication of postponed data such as credit sales data, the communication data is registered in the communication data storage file 61 in the order of occurrence by the processing of ST15 and ST16, and the transmission is postponed.

Further, the CPU 41 executes the processing shown in FIG. 6C according to the postponement data transmission program 53 every time an interrupt signal is inputted to the interrupt terminal q.

That is, first, at ST21, the data number counter 61b of the communication data storage file 61 is checked.
When the count value S is "0", there is no communication data for which transmission has been postponed, so the processing of this time is ended.

On the other hand, when the count value S is "1" or more, the traffic amount TR per unit time exceeds the traffic limit value TR0, and communication data whose transmission has been postponed occurs in the communication data area 61a. Since they are registered in order, the latest traffic amount TR per unit time stored in the calculated value memory 66 as ST22 is set to the allowable traffic value T preset in the allowable value memory 65.
Compared with R1, it is judged whether or not the traffic volume TR satisfies the communication enable condition of the traffic allowable value TR1 or less.

If the traffic volume TR exceeds the traffic tolerance value TR1 and the communication enable condition is not satisfied, the current process is terminated.

On the other hand, when the traffic volume TR is equal to or less than the traffic allowable value TR1 and the communication enable condition is satisfied, the communication data area 61 is set as ST23.
The oldest communication data in a is read and the data transmission process by the contention method is executed. Then, after transmitting the data, in ST24, if the transmitted communication data is deleted from the communication data area 61a and the data number counter 61b is counted down by "-1",
This processing ends.

Therefore, it is checked at intervals of 1 second whether there is data postponed by the processing of ST21. Then, if it exists, it is checked whether or not the traffic amount is reduced and the communicable condition is satisfied. Then, only when the communicable condition is satisfied, the deferred communication data is wirelessly transmitted every time the wireless slave station acquires the transmission right in the old order.

As described above, according to the present embodiment, the data wirelessly transmitted from each of the POS terminals 1a to 1f to the host computer 2 is, for example, some data which cannot be postponed because high-speed response is required. During the period in which the traffic volume TR per unit time is increasing so as to exceed the preset traffic limit value TR1, the transmission processing is not performed, and it is stored in the communication data storage file 61 as standby data. Then, the communication data stored in the communication data storage file 61 is sequentially wirelessly transmitted when the traffic amount TR decreases and the communicable condition is satisfied. Therefore, even in an environment where the traffic volume of wireless communication increases, such as when the frequency of sales registration significantly increases due to busy stores,
It is possible to prevent the traffic volume of wireless communication from significantly increasing.

As a result, the amount of wireless communication traffic is suppressed as much as possible, so that the time spent until each of the wireless slave stations 4a to 4f acquires the transmission right is surely shortened. Therefore, the processing of data that requires a response such as a unit price inquiry can be performed at high speed, and the processing capability of the POS terminals 1a to 1f can be improved. Further, the number of communication collisions is reduced, so that the system does not go down due to communication failure.

Further, in the present embodiment, the communication data table 67 in which the priority flag can be set for each type of communication data is provided, and the priority flag is set for the unsuspendable data such as the unit price inquiry. Even when the traffic amount TR per hit exceeds the traffic limit value TR0, transmission processing is performed without delay. Therefore, data that requires a high-speed response such as a unit price inquiry will not be postponed, and the system will not fail.

In the wireless data communication system, if there is no data that cannot be postponed, such as data that requires a high-speed response, the processes of ST13 and ST14 in the data communication determination program 52 are omitted. For all communication data transmission requests, the traffic volume TR and traffic limit value TR0 prior to data transmission
When the traffic volume TR exceeds the traffic limit value TR0, the data transmission may be postponed. In this case, the communication data table 67 can be omitted.

In the above embodiment, the present invention is applied to the wireless slave station 4.
It is needless to say that the invention is applied to the wireless base stations 3a and 3b, although it is applied to a to 4f.

In addition to the above, the present invention is applied to a system having one or three or more wireless base stations, a system in which the number of wireless slave stations is different from that of this embodiment, and the like without departing from the scope of the present invention. Of course, various modifications can be implemented.

[0066]

As described above in detail, according to the present invention, in a wireless data communication system adopting a contention system as a wireless communication system, the wireless communication system can be used even under an environment where the traffic volume of the wireless communication increases. The amount of traffic can be reduced as much as possible, and the response time for the transmission of data that requires a response can be reliably shortened.
It is possible to provide a wireless data communication device capable of preventing system down caused by a significant increase in traffic volume and always performing stable data communication.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a host computer according to an embodiment of the present invention.

FIG. 2 is a block diagram of a main part of the POS terminal according to the embodiment.

FIG. 3 is a block diagram of a main part of a wireless slave station according to the embodiment.

FIG. 4 is a diagram showing a main memory area formed in a ROM of the wireless slave station.

FIG. 5 is a diagram showing a main memory area formed in a RAM of the wireless slave station.

FIG. 6 is a flowchart showing a main part of main program processing executed by a CPU of the wireless slave station.

FIG. 7 is an overall view of a general wireless POS system.

[Explanation of symbols]

 1a to 1f ... POS terminal 2 ... Host computer 3a, 3b ... Wireless base station 4a-4f ... Wireless slave station 41 ... CPU 42 ... ROM 43 ... RAM 46 ... Wireless circuit section 46e ... Carrier sense section 51 ... Wireless traffic calculation program 52 ... Data communication determination program 53 ... Postponed data transmission program 61 ... Communication data storage file 67 ... Communication data table

Claims (2)

[Claims] 1. A wireless data communication device for determining whether or not a wireless line is being used by another device during transmission of communication data, and acquiring a transmission right to wirelessly transmit the communication data when it is not in use. A traffic amount measuring means for measuring a traffic amount per unit time of the wireless circuit, and comparing the traffic amount measured by the traffic amount measuring means with a preset threshold value prior to the transmission processing of the communication data. Data transmission determining means for determining whether or not to immediately perform transmission, and when this determination means determines that the traffic volume is equal to or less than the threshold value and transmission is immediately performed, the communication data is processed for transmission. When the traffic volume exceeds the threshold value and the transmission delay is determined by the communication data transmission processing means and the determination means, Communication data storage means for temporarily storing communication data, and transmission processing of the communication data stored in the communication data storage portion by the storage means when the traffic amount satisfies a communicable condition equal to or less than the threshold value. A wireless data communication device comprising: postponement data transmission means. 2. The data transmission determination means has a determination means for determining whether or not the communication data can be postponed depending on the type of communication data, and determines whether or not only the communication data that can be postponed is immediately transmitted based on the traffic volume. The wireless data communication apparatus according to claim 1, wherein the communication data that cannot be postponed is immediately transmitted regardless of the traffic volume.