Patent Publication Number: US-2022230156-A1

Title: Checkout system and portable point-of-sale terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/921,413, filed on Jul. 6, 2020, which is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-171935, filed on Sep. 20, 2019, the entire contents of each of which are incorporated herein by reference. 
    
    
     FIELD 
     Embodiments described herein relate generally to a checkout system for a retail store or the like and a portable point-of-sale (POS) terminal that can be used in the checkout system or otherwise. 
     BACKGROUND 
     A point-of-sale (POS) register application can be installed in an information processing device, such as a general-purpose tablet PC (Personal Computer), to permit the information processing device to be used as a portable POS terminal. The portable POS terminal can be wirelessly connected to a network provided in a store to use various, peripheral devices such as a receipt printer, an automatic coin change machine, or a scanner (e.g., a bar code scanner) connected to the network. 
     If one of the peripheral device is out of order in such a checkout system of this type, a reference proposes a technique for enabling an external information processing terminal to provide information indicating an operation state of the peripheral device(s). 
     However, there is the problem of keeping customers waiting if the peripheral device is out of order. In particular, the receipt printer often experiences failures because the receipt printer includes a mechanical paper conveying system that is more likely to fail with use. As a result, customers ready for checkout are frequently kept waiting until the receipt printer is repaired. Failures of other peripheral devices are also possible. For example, other peripheral devices including driving systems are more likely to break than peripheral devices that do not include driving systems. In addition to such failures, the peripheral devices may become unusable because of troubles such as a network failures or the like. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a network of a checkout system according to an embodiment. 
         FIG. 2  is a schematic diagram illustrating a positional relation among elements in a checkout system to an embodiment. 
         FIG. 3  is a block diagram illustrating aspects of a configuration of a server. 
         FIG. 4  is a block diagram illustrating aspects of a tablet functioning as a portable POS terminal according to an embodiment. 
         FIG. 5  is a flowchart illustrating aspects of position coordinate control processing executed by a processor of a server. 
         FIG. 6  is a flowchart illustrating aspects of a peripheral device-use processing executed by a processor of a tablet. 
         FIG. 7  is a flowchart illustrating aspects of priority setting processing. 
         FIGS. 8-11  are schematic diagrams illustrating examples of screens displayed on a tablet. 
         FIG. 12A  is a diagram illustrating a first portion of a flowchart illustrating an example of a procedure of device-use processing. 
         FIG. 12B  is a diagram illustrating a second portion of the flowchart illustrating the example of the procedure of device-use processing. 
         FIGS. 13-14  are schematic diagrams illustrating examples of screens displayed on a tablet. 
     
    
    
     DETAILED DESCRIPTION 
     One or more embodiments are directed to providing a wireless checkout system and a portable POS terminal used in the system (and a control program for causing a computer to function as such a portable POS terminal) that can reduce a waiting time of a customer if a peripheral device normally available in the system is in an unusable state. 
     In general, according to an embodiment, a wireless checkout system includes a plurality of peripheral stations located in a store area, a server that stores location information indicating a position coordinate of each of the peripheral stations in the store area, one or more base stations having a wireless communication range covering the store area, and a mobile point-of-sale (POS) terminal. The mobile POS terminal includes a wireless communication interface configured to receive a wireless signal from at least one of the one or more base stations, a display, and a processor. The processor is configured to designate one of the plurality of peripheral stations as an associated peripheral station to be communicated with for checkout by the mobile POS terminal, determine a position coordinate of the mobile POS terminal based on the wireless signal received by the wireless communication interface, obtain the location information, selected, based on the position coordinate of the mobile POS terminal and the location information, a closest one of the plurality of peripheral stations to the mobile POS terminal, other than the associated peripheral station, to be an alternative peripheral station to be recommended for checkout, if the associated peripheral station is not available. The processor then controls the display to display a screen indicating the alternative peripheral station. 
     A checkout system and a portable POS terminal used in this system according to an embodiment that can reduce a waiting time of a customer if a peripheral device that the portable POS terminal attempts to communicate with is in an unusable state are explained with reference to the drawings. 
       FIG. 1  is a diagram of the checkout system according to the embodiment. The checkout system includes a server  10 , a plurality of automatic coin change machines  20 , a plurality of keyboards  30 , a plurality of receipt printers  40 , a plurality of card settlement terminals  50 , and a plurality of ticket printers  60  functioning as peripheral devices (may be referred to as peripheral stations) and a plurality of tablets  70 . The checkout system may be referred to as a wireless checkout system or a mobile POS checkout system. The tablet  70  is the portable POS terminal according to the present embodiment. The tablet  70 , in this context, is an example of a hand-held or mobile POS terminal. The server  10 , the plurality of types of peripheral devices, and the plurality of tablets  70  are connected to one another via a network NW such as a LAN (Local Area Network) provided in a store. The server  10  is connected to the network NW by wire via a gateway. The plurality of types of peripheral devices are connected to the network NW by wire. At least any one type among the peripheral devices or a least one of at least one type of peripheral devices may be wirelessly connected to the network NW via an access point. The plurality of tablets  70  are wirelessly connected to the network NW via an access point. The checkout system includes the plurality of types of peripheral devices. However, the checkout system may include only one peripheral device. Similarly, the checkout system may include only one tablet  70 . 
     The server  10  is a store server for, for example, collecting data of commodities registered by the tablets  70  and managing sales, stocks, and the like of the entire store. The automatic coin change machine  20  includes a depositing port and a dispensing port for cash. The automatic coin change machine  20  counts, for each of denominations, the number of coins or bills deposited from the deposit port to calculate a deposit amount and transmits data of the deposit amount to the tablet  70 . The automatic coin change machine  20  dispenses cash equivalent to coin from the dispensing port based on coin data received from the tablet  70 . Various keys for auxiliary input for the tablet  70  are disposed on the keyboard  30 . The receipt printer  40  prints a receipt. The card settlement terminal  50  is a terminal for performing payment by a credit card or an electronic money medium. The ticket printer  60  prints a ticket such as a discount ticket. 
     The tablet  70  has at least the following first to fourth functions. The first function is a function of registering sales data of commodities purchased by a customer. The second function is a function of generating payment data based on the registered commodity sales data. The third function is a function of receiving price payment from a customer based on the generated payment data and settling a commercial transaction with the customer. The fourth function is a function of generating a printing job for a receipt indicating details of the commercial transaction and wirelessly transmitting the printing job to the receipt printer  40 . 
     The checkout system further includes position measurement tags (abbreviated as TG in  FIG. 1 ) attached to or incorporated in the respective peripheral devices and a plurality of stationary base stations  90  connected to the network NW. The plurality of stationary base stations  90  are connected to the network NW by wire. The plurality of stationary base stations  90  may be directly connected to the server  10  by an exclusive line separate from the network NW. 
       FIG. 2  is a schematic diagram illustrating a physical positional relation among elements in the checkout system in a store area. In  FIG. 2 , the reference sign “NWS” represents network segments in the network NW connected to one another by bridges or the like. In an embodiment, the store area may consist of a plurality of network segments NWS. The automatic coin change machines  20  are abbreviated as “CM,” the keyboards are abbreviated as “KB,” the receipt printers  40  are abbreviated as “RP,” the card settlement terminals  50  are abbreviated as “CT,” the ticket printers  60  are abbreviated as “TP,” the tablets  70  are abbreviated as “TT,” the position measurement tags  80  are abbreviated as “TG,” and the stationary base stations  90  are abbreviated as “BS.” As illustrated in  FIG. 2 , the stationary base stations  90  are fixedly set in predetermined positions in the store. The stationary base stations  90  are suitably set at equal intervals in an X direction and a Y direction, for example, on a ceiling of the store but are not limited to this arrangement. A positional relation between the network segments NWS and the stationary base stations  90  is not particularly limited either. 
     The position measurement tags  80  and the stationary base stations  90  are connected to the network NW and function as measurement devices that measure position coordinates of the respective peripheral devices in the store. The stationary base stations  90  transmits BLE (Blue Tooth® Low Energy) waves or UWB (Ultra Wide Band) waves. The position measurement tags  80  receive the BLE waves or the UWB waves. Position coordinates of the position measurement tags  80 , that is, position coordinates of peripheral devices to which the position measurement tags  80  are attached can be measured based on incident angles and arrival times of the BLE waves or the UWB waves. Alternatively, the position measurement tags  80  transmit BLE waves or UWB waves and the stationary base stations  90  receive the BLE waves or UWB waves. Position of the position measurement tags  80  can be measured based on incident angles and arrival times of the BLE waves or the UWB waves at the stationary base stations  90 . For example, in in  FIG. 2 , as position coordinates of the three receipt printers  40 , (x, y)=(5, 8), (x, y)=(14, 2), and (x, y)=(27, 9) are measured. 
       FIG. 3  is a block diagram illustrating a configuration of the server  10 . The server  10  includes, as illustrated in  FIG. 3 , a processor  11 , a main memory  12 , an auxiliary storage device  13 , a communication interface  14 , a timer  15 , and a system transmission line  16 . The system transmission line  16  includes an address bus, a data bus, and a control signal line. In the server  10 , the processor  11 , the main memory  12 , the auxiliary storage device  13 , the communication interface  14 , and the timer  15  are connected to the system transmission line  16 . In the server  10 , the processor  11 , the main memory  12 , and the auxiliary storage device  13  form a computer and the system transmission line  16  connects the foregoing components. 
     The processor  11  controls the units in order to perform various functions according to an operating system or application programs (software programs). The processor  11  is, for example, a CPU (Central Processing Unit). 
     The main memory  12  includes a nonvolatile memory region and a volatile memory region. The main memory  12  stores the operating system or the application programs in the nonvolatile memory region. The main memory  12  can store, in the nonvolatile or volatile memory region, data necessary for the processor  11  to execute processing for controlling the units. The main memory  12  uses the volatile memory region as a work area in which data is rewritten as appropriate by the processor  11 . The nonvolatile memory region is, for example, a ROM (Read Only Memory). The volatile memory region is, for example, a RAM (Random Access Memory). In this embodiment, a position table  121 , which stores position coordinates of the peripheral devices, is in the volatile memory region of the main memory  12 . 
     For example, an EEPROM (Electric Erasable Programmable Read-Only Memory), an HDD (Hard Disk Drive), or an SSD (Solid State Drive) can be the auxiliary storage device  13 . The auxiliary storage device  13  stores data used by the processor  11  in performing various kinds of processing, data created by processing in the processor  11 , and the like. The auxiliary storage device  13  sometimes stores the application programs. In the auxiliary storage device  13 , a commodity database (DB)  131 , a sales database (DB)  132 , and the like are provided. The commodity database  131  stores, for each of commodities sold in the store, commodity records in which various commodity data and information are described. The commodity record includes a commodity code (may also be referred to as a product code), a price, and a commodity name. The commodity code is an identification code of a corresponding commodity. The sales database  132  stores sales records in which sales data (transaction records) can be provided by such matters/items as a commodity type, a store department, a time period range, a date, a week, or a month. The sales data includes the number of sold items and a sales amount. 
     The communication interface  14  is connected to the network NW. The communication interface  14  performs, according to a communication protocol, data communication between the communication interface  14  and other devices connected via the network NW. 
     The timer  15  starts a time tracking operation according to a command from the processor  11 . The timer  15  times out if a preset time is reached. A time when the timer  15  times out can be optionally set. 
       FIG. 4  is a block diagram illustrating a configuration of the tablet  70 . The tablet  70  in this example is a general-purpose tablet PC. The tablet  70  downloads and installs a control program according to the present embodiment. The control program is also referred to as a POS register application. The tablet  70  executes the control program to function as the portable POS terminal according to the present embodiment. The tablet  70  includes, as illustrated in  FIG. 4 , a processor  71 , a main memory  72 , an auxiliary storage device  73 , a touch panel  74 , a wireless unit  75 , a sensor group  76 , a speaker  77 , and a system transmission line  78 . The system transmission line  78  includes an address bus, a data bus, and a control signal line. In the tablet  70 , the processor  71 , the main memory  72 , the auxiliary storage device  73 , the touch panel  74 , the wireless unit  75 , the sensor group  76 , and the speaker  77  are connected to the system transmission line  78 . 
     The processor  71  controls the units in order to perform various functions according to an operating system and/or application programs. The processor  71  is, for example, a CPU. 
     The main memory  72  includes a nonvolatile memory region and a volatile memory region. The main memory  72  stores the operating system or the application programs in the nonvolatile memory region. The main memory  72  sometimes stores, in the nonvolatile or volatile memory region, data necessary for the processor  71  to execute processing for controlling the units. The main memory  72  uses the volatile memory region as a work area in which data is rewritten as appropriate by the processor  71 . The nonvolatile memory region is, for example, a ROM. The volatile memory region is, for example, a RAM. 
     For example, an EEPROM or an SSD can be the auxiliary storage device  73 . The auxiliary storage device  73  stores data used by the processor  71  in performing various kinds of processing, data created by processing in the processor  71 , and the like. The auxiliary storage device  73  may store the application programs. In this embodiment, the auxiliary storage device  73  stores a POS register application  731  (abbreviated as “POS application” in  FIG. 4 ). The auxiliary storage device  73  provides a priority setting memory  7311  that stores priority setting information, which is data that the processor  71  rewrites as appropriate during execution of the POS register application  731 . 
     The touch panel  74  is a device functioning as both of an input device and a display device of the tablet  70 . The touch panel  74  functions as a display. The touch panel  74  detects a touch position for a displayed image and outputs information concerning the touch position to the processor  71 . The touch panel  74  displays, for example, names, prices, and total amounts of commodities registered by the tablet  70 . 
     The wireless unit  75  is connected to the network NW via an access point and performs data communication with the server  10  and the peripheral devices. The wireless unit  75  functions as a network interface unit. The wireless unit  75  may be referred to as a wireless communication interface. The wireless unit  75  has a function of transmitting or receiving a BLE wave or a UWB wave and thus can perform substantially the same functions as a position measurement tag  80 . The wireless unit  75  further functions as a detecting unit. For example, in the example illustrated in  FIG. 2 , (x, y)=(8, 2) is detected as a position coordinate of the tablet  70 . If the wireless unit  75  is not adapted to the BLE wave or the UWB wave, as in the peripheral devices, the position measurement tag  80  may be attached to the tablet  70 . 
     The sensor group  76  includes a camera, a GPS sensor, a gyro sensor, and the like. The camera can read a code symbol such as a barcode or a two-dimensional data code attached to a commodity. The camera may thus serve as an optical code reader. The speaker  77  outputs warning sound or the like. 
     The POS register application  731  is an application for causing the processor included in the tablet  70  to function as an acquiring unit, a presenting unit, a setting unit, a designating unit, and a selecting unit. The POS register application  731  can be stored in the auxiliary storage device  73  and accessed by communication performed via a network. The POS register application  731  may be recorded in a removable recording medium such as a CD-ROM or a memory card and distributed. In this case, the POS register application  731  can be read from the recording medium by a recording medium reader connected to the tablet  70  or a recording medium reader included in or connected to a personal computer that can communicate with the tablet  70  and can be stored in the auxiliary storage device  73 . 
     The acquiring unit acquires, from the network NW, position coordinates of a respective plurality of peripheral devices, position coordinates of which in the store can be acquired, connected to the network NW. The presenting unit is a unit that, if a first peripheral device is unusable when communication with the first peripheral device is attempted via the network NW, presents, as a use recommended device (may be referred to as an alternative peripheral device or station), a second peripheral device at a position coordinate the shortest distance from the tablet  70  (excepting the first peripheral device). The setting unit sets a peripheral-device-to-be-preferentially-used (preferred peripheral device) among the plurality of peripheral devices. The designating unit designates whether the peripheral-device-to-be-preferentially-used or a peripheral device at the position coordinate the shortest distance from the tale  70  is prioritized. The selecting unit selects, as the first peripheral device, the peripheral device designated by the designating unit. In some examples, the selecting unit may select without reference to the designation by the designating unit, the peripheral-device-to-be-preferentially-used (may be referred to as an associated peripheral device or station). Alternatively, the selecting unit may select, without depending on the setting by the setting unit or the designation by the designating unit, the peripheral device at the position coordinate at the shortest distance from the tablet  70  as the first peripheral device. 
     In the following explanation, the operation of the checkout system according to the embodiment is specifically explained with reference to the flowcharts of  FIGS. 5 and 6 . Content of processing explained with reference to  FIGS. 5 and 6  is an example. A processing procedure and processing content are not particularly limited if the same result can be obtained. 
       FIG. 5  is a flowchart illustrating an example of a procedure of position coordinate control, which is one of many kinds of control processing executed by the processor  11  of the server  10 . As illustrated in  FIG. 5 , in Act  11 , the processor  11  determines whether to acquire a position coordinate of a peripheral device. This determination can be performed by determining whether acquisition timing predetermined in order to acquire a position coordinate of the peripheral device comes. It is optional to determine to which degree the acquisition timing is set. Unlike the tablet  70 , the peripheral device does not frequently move. Therefore, the acquisition timing may be a several seconds to several ten seconds interval. This interval can be set as a tracked time of the timer  15 . Therefore, in Act  11 , if the timer  15  times out, the processor  11  can determine to acquire a position coordinate of the peripheral device. If not acquiring a position coordinate of the peripheral device, the processor  11  determines NO in Act  11  and the process proceeds to Act  12 . In Act  12 , the processor  11  determines whether a transmission request for location information including a position coordinate designating a type of a peripheral device such as a receipt printer is received from any tablet  70  via the network NW. If a transmission request for location information is received from no tablet  70 , the processor  11  determines NO in Act  12  and the process proceeds to Act  11 . 
     If the acquisition timing for acquiring a position coordinate of the peripheral device when the timer  15  times out comes, the processor  11  determines YES in Act  11  and the process proceeds to Act  13 . In Act  13 , the processor  11  acquires position coordinates from the respective peripheral devices, that is, the plurality of automatic coin change machines  20 , the plurality of keyboards  30 , the plurality of receipt printers  40 , the plurality of card settlement terminals  50 , and the plurality of ticket printers  60 . In Act  14 , the processor  11  registers the acquired position coordinates of the peripheral devices in the position table  121  provided in the main memory  12 . At this time, the processor  11  causes the timer  15  to start a time tracking operation. Thereafter, the process proceeds to Act  11 . 
     If receiving a transmission request for location information from any tablet  70  via the network NW, the processor  11  determines YES in Act  12  and the process proceeds to Act  15 . In Act  15 , the processor  11  transmits location information including a position coordinate of the peripheral device of the designated type registered in the position table  121  to the tablet  70  at a request source via the network NW. Thereafter, the process proceeds to Act  11 . 
       FIG. 6  is a flowchart illustrating an example of a procedure of peripheral device-use processing, which is one of a large number of kinds of control processing by the POS register application  731  executed by the processor  71  of the tablet  70 . 
     In Act  71 , the processor  71  of the tablet  70  determines whether processing for priority setting is instructed by operation of the touch panel  74 . The processing for priority setting is processing for setting a peripheral device to be preferentially used among the plurality of peripheral devices. For example, the processor  71  determines whether a touch position for a [priority setting] button image displayed on the touch panel  74  is touched or whether a touch position for a corresponding item image is touched from a menu item displayed according to touch on a touch position for a [menu] button image. “Button” discussed above and described hereinafter is an example of a selectable object unless the button is in a non-selectable state, in which case may be referred to as a “non-selectable object”. If the processing for priority setting is not instructed, the processor  71  determines NO in Act  71  and the process proceeds to Act  72 . The processor  71  determines whether use of any peripheral device is instructed by operation of the touch panel  74 . For example, the processor  71  determines whether a touch position for a button image indicating peripheral device operation content such as a [receipt print] button image displayed on the touch panel  74  is touched or whether a touch position for a corresponding item image is touched from a menu item displayed according to touch on a touch position for the [menu] button image. If use of a peripheral device is not instructed, the processor  71  determines NO in Act  72  and the process proceeds to Act  71 . 
     If the processing for priority setting is instructed, the processor  71  determines YES in Act  71  and the process proceeds to Act  73 . In Act  73 , the processor  71  performs priority setting processing for setting a peripheral device to be preferentially used. Thereafter, the process proceeds to Act  71 . 
       FIG. 7  is a flowchart illustrating an example of a procedure of the priority setting processing in Act  73 .  FIGS. 8 to 11  are schematic diagrams illustrating examples of screens displayed on the touch panel  74  of the tablet  70  in the priority setting processing. 
     In the priority setting processing, in Act  731 , as illustrated in  FIG. 8 , the processor  71  causes the touch panel  74  to display a type designation screen  741 . The type designation screen  741  is a screen for designating a type of a peripheral device to be preferentially set. The type designation screen  741  includes a plurality of peripheral device type designation button images  7411  for designating a peripheral device. As illustrated in  FIG. 8 , the type designation screen  741  may include a [return] button image  7412  for instructing return to an immediately preceding screen even if the processing for priority setting is stopped. Thereafter, the process proceeds to Act  732  and waits for any peripheral device to be set. In other words, the processor  71  waits for a touch position for any peripheral device type designation button image  7411  to be touched. If a touch position for any peripheral device type designation button image  7411  is touched, in Act  733 , the processor  71  causes the priority setting memory  7311  to store, as one of priority setting information, priority device information indicating a peripheral device corresponding to the touch position. Thereafter, the process proceeds to Act  734 . 
     In Act  734 , as illustrated in  FIG. 9 , the processor  71  causes the touch panel  74  to display a priority designation screen  742 . The priority designation screen  742  is a screen for designating, concerning the peripheral device designated on the type designation screen  741 , in an example illustrate in  FIG. 9 , a receipt printer, which of a distance and the designates device is prioritized. The priority designation screen  742  includes two priority designation button images  7421  for designating the distance or the designated device to be prioritized. Thereafter, the process proceeds to Act  735  and waits for any peripheral device to be designated. In other words, the processor  71  waits for a touch position for any priority designation button image  7421  to be touched. If the touch position for any priority designation button image  7421  is touched, in Act  736 , the processor  71  causes the priority setting memory  7311  to store, as one of priority setting information, priority designation information indicating priority designation corresponding to the touch position. In this way, the processor  71  functions as a designating unit. Thereafter, the process proceeds to Act  737 . 
     If a touch position for any peripheral device type designation button image  7411  is touched, the processor  71  may cause the touch panel  74  to display a priority designation screen  743  illustrated in  FIG. 10  rather than the priority designation screen  742  illustrated in  FIG. 9 . The priority designation screen  743  is a screen for designating, concerning the peripheral device designated on the type designation screen  741 , in an example illustrated in  FIG. 10 , a receipt printer, which of a distance and the designated device is prioritized and to which degree the distance or the designated device is prioritized. The priority designation screen  743  includes the slider image  7431  for designating the priority to be prioritized. Thereafter, the process proceeds to Act  735  and the processor  71  waits for a priority level to be designated. In other words, the processor  71  waits for any touch position corresponding to a slider image  7431  to be touched. If any touch position is touched, in Act  736 , the processor  71  causes the priority setting memory  7311  to store, as one of priority setting information, priority designation information indicating priority level designation corresponding to the touch position. Priority levels of 0 to 100% can be set according to a position touched for the slider image  7431 . In this way, the processor  71  functions as a designating unit. Thereafter, the process proceeds to Act  737 . 
     In Act  737 , as illustrated in  FIG. 11 , the processor  71  causes the touch panel  74  to display a priority device designation screen  744 . The priority device designation screen  744  is a screen for designating, concerning the peripheral device designated on the type designation screen  741 , in an example illustrated in  FIG. 11 , a receipt printer, which device is designated as a priority device. The priority device designation screen  744  includes a plurality of priority device designation button images  7441  for designating the priority device. The priority device designation screen  744  includes not only peripheral devices present in the network segment NWS in which the tablet  70  is located but also peripheral devices present in the other network segments NWS. If the number of peripheral devices is large and the peripheral devices cannot be displayed on one screen, the screen is scrolled or switched by scroll operation. Thereafter, the process proceeds to Act  738  and waits for any peripheral device to be designated. In other words, the processor  71  waits for a touch position for any priority device designation button image  7441  to be touched. If a touch position for any priority device designation button image  7441  is touched, in Act  739 , the processor  71  causes the priority setting memory  7311  to store, as one of priority setting information, priority device designation information indicating priority device designation corresponding to the touch position. In this way, the processor  71  functions as a setting unit. Thereafter, the process returns to Act  71  in  FIG. 6 . 
     Priority setting can be performed for each of types of the plurality of peripheral devices. 
     If it is instructed to use any peripheral device, the processor  71  determines YES in Act  72  and the process proceeds to Act  74 . In Act  74 , the processor  71  performs device-use processing for using the peripheral device. Thereafter, the process proceeds to Act  71 . 
       FIGS. 12A and 12B  are flowcharts illustrating an example of a procedure of the device-use processing in Act  74 .  FIGS. 13 and 14  are schematic diagrams illustrating examples of screens displayed on the touch panel  74  of the tablet  70  in the device-use processing. 
     In the device-use processing, in Act  741 , the processor controls the wireless unit  75  to detect a position coordinate of its own device (that is, the device incorporating the processor  71 ) in the store. Thereafter, the processor  71  controls the wireless unit  75  to transmit a transmission request for location information including a position coordinate concerning a peripheral device of a type instructed to the server  10  via the network NW. The process proceeds to Act  743  and the processor  71  waits for the position coordinate of the peripheral device from being received from the server  10  by the wireless unit  75 . 
     If the server  10  transmits a position coordinate of a peripheral device of a designated type registered in the position table  121  and the position coordinate of the peripheral device is received by the wireless unit  75 , the processor  71  determines YES in Act  743  and the process proceeds to Act  744 . In this way, the processor  71  functions as an acquiring unit. In Act  744 , the processor  71  calculates distances between itself (its own device location) and peripheral devices based on the its detected position coordinate in the store and position coordinates of the acquired peripheral devices of the designated type. The distances are typically linear distances. However, if a complicated passage is formed by arrangements in the store, a store map may be stored in the auxiliary storage device  73  in advance and a moving distance along a route (that a potentially non-straight line distance) may be calculated in this context. In Act  745 , the processor  71  ranks the peripheral devices based on the calculated distances and the priority setting information stored in the priority setting memory  7311 . For example, concerning the receipt printer  40 , if a receipt printer # 2  is designated as a priority device and the priority designation is the designated device, the processor  71  ranks the receipt printer # 2  in the first place and ranks the peripheral devices in the second and subsequent places in ascending order of the distances. If the priority designation is the distance, the processor  71  ranks the peripheral device at the shortest distance in the first place and ranks the peripheral devices in the second and subsequent places in ascending order of the distances. If a type of a peripheral device designated to be used is a type for which priority setting information is not stored in the priority setting memory  7311 , the processor  71  performs ranking based on the distances. The processor  71  selects the peripheral device in the first place as a first peripheral device attempted to be communicated with. In this way, the processor  71  functions as a selecting unit. Thereafter, the process proceeds to Act  746 . 
     In Act  746 , the processor  71  executes a procedure for using the peripheral device ranked in the first place. For example, the processor  71  generates a print job for a receipt and controls the wireless unit  75  to transmit the print job to the receipt printer # 2  in the first place. Thereafter, the process proceeds to Act  747 . In Act  747 , the processor  71  determines whether the procedure normally ends. A response signal indicating the normal end is returned from the receipt printer  40  that successfully normally executes the print job. A response signal indicating an abnormal end is returned from the receipt printer  40  that does not successfully normally execute the print job. If receiving the response signal indicating the normal end within a predetermined time, the processor  71  determines that the print job normally ends. If receiving the response signal indicating the abnormal end within the predetermined time or if not successfully receiving the response signal indicating the normal end or the abnormal end within the predetermined time, the processor  71  determines that the print job does not normally end. The predetermined time is determined based on a normal processing time statistically requested for each of the types of the peripheral devices. For example, the predetermined time is approximately three seconds for the receipt printer  40 . 
     If the use of the peripheral device normally ends, the processor  71  determines YES in Act  747  and the process returns to Act  71  in  FIG. 6 . 
     If the use of the peripheral device does not normally end, the processor  71  determines NO in Act  747  and the process proceeds to Act  748 . In Act  748 , the processor  71  causes the touch panel  74  to display a guidance screen  745  as illustrated in  FIG. 13 . The guidance screen  745  is a screen for notifying that a preferentially designated peripheral device cannot be used and presenting a peripheral device recommended as an alternative device for the peripheral device. In other words, the guidance screen  745  includes a use recommended device display area  7451  for presenting such a peripheral device. The peripheral device displayed in the use recommended device display area  7451  is the peripheral device in the second place ranked in Act  745 , that is, the second peripheral device present in a position coordinate at the shortest distance from the tablet  70  except the first peripheral device, which is the preferentially designated peripheral device. In this way, the processor  71  functions as a presenting unit. 
     The guidance screen  745  includes, as illustrated in  FIG. 13 , a recommendation button image  7452 , a designation button image  7453 , and a standby button image  7454 . The recommendation button image  7452  is an image of a button touched when instructing use of the peripheral device recommended as the alternative device. The recommendation button image  7452  has a display area larger than display areas of the other buttons. The designation button image  7453  is an image of a button touched when instructing use of a peripheral device other than the recommended peripheral device. The standby button image  7454  is an image of a button touched when instructing to continue the use of the preferentially designated peripheral device. After displaying the guidance screen  745 , the process proceeds to Act  749  and the processor  71  waits for operation that should be performed next to be selected. In other words, the processor  71  waits for a touch position for any one of the recommendation button image  7452 , the designation button image  7453 , and the standby button image  7454  to be touched. If any touch position is touched, the process proceeds to Act  7410 . 
     In Act  7410 , the processor  71  determines whether the touch position for the standby button image  7454  is touched. If the touch position for the standby button image  7454  is touched, the processor  71  determines YES in Act  7410 , and the process returns to Act  746 , where the processor  71  attempts to communicate with the preferentially designated peripheral device again. Retry may be prevented from being repeated many times by restricting the standby button image  7454  to be displayed only a predetermined number of times such as twice. 
     If the touch position for the standby button image  7454  is not touched, the processor  71  determines NO in Act  7410  and the process proceeds to Act  7411 . In Act  7411 , the processor  71  determines whether the touch position for the designation button image  7453  is touched. If the touch position for the designation button image  7453  is not touched, that is, the touch position for the recommendation button image  7452  is touched, the processor  71  determines NO in Act  7411  and the process proceeds to Act  7412 . In Act  7412 , the processor  71  changes the peripheral device to be used to the recommended peripheral device in this case. The process returns to Act  746  and the processor  71  attempts to communicate with the peripheral device changed from the peripheral device to be used. 
     If the touch position for the designation button image  7453  is touched, the processor  71  determines YES in Act  7411  and the process proceeds to Act  7413 . In Act  7413 , the processor  71  causes the touch panel  74  to display a selection screen  746  as illustrated in  FIG. 14 . The selection screen  746  includes a plurality of peripheral device button images  7461  for designating the peripheral device to be used. The peripheral device button image  7461  corresponding to the recommended peripheral device, in an example illustrated in  FIG. 14 , the receipt printer # 1  is displayed in a form different from a form of the other peripheral devices such that the peripheral device button image  7461  can be identified. The peripheral device button image  7461  corresponding to an unusable peripheral device, which does not normally end, in the example illustrated in  FIG. 14 , the receipt printer # 2  is displayed in an un-selectable display form. If the number of peripheral devices is large and the peripheral devices cannot be displayed on one screen, the screen is scrolled or switched by scroll operation. Thereafter, the process proceeds to Act  7414  and the processor  71  waits for any peripheral device to be designated. In other words, the processor  71  waits for a touch position for any peripheral device button image  7461  to be touched. If the touch position for any peripheral device button image  7461  is touched, the processor  71  determines YES in Act  7414  and the process proceeds to Act  7412 . In Act  7412 , the processor  71  changes the peripheral device to be used to the designated peripheral device in this case. The process returns to Act  746  and the processor  71  attempts to communicate with the peripheral device changed from peripheral device to be used. 
     In this way, according to this embodiment, if communication with the first peripheral device is attempted in the tablet  70  and the first peripheral device is unusable, the second peripheral device present in a position coordinate at the shortest distance from the tablet  70  except the first peripheral device is presented as the use recommended device. Accordingly, it is possible to find the use recommended device presented when the peripheral device attempted to be communicated from the tablet  70  is in an unusable state and switch a use destination to another peripheral device. Therefore, it is possible to reduce a waiting time of a customer. Since it can be found which peripheral device is a switching destination, it is possible to easily guide the customer to the position of the peripheral device. 
     It can be selected in advance whether the first peripheral device will be a peripheral device close to the tablet  70  or a peripheral device designated to be preferentially used. Accordingly, it is possible to use an appropriate peripheral device corresponding to a situation of the customer or the store. 
     If the first peripheral device is the peripheral device close to the tablet  70 , the waiting time of the customer can be reduced. Time for guiding the customer to another position or time for the customer moving to the position can be saved. 
     If the first peripheral device is the peripheral device desired to be preferentially used, a peripheral device in a predetermined position can be used first. Therefore, the customer is not guided to a position unexpected by the customer. It is less likely to confuse the customer. 
     The checkout system and the portable POS terminal used in this system according to the embodiment that can reduce a waiting time of a customer if a peripheral device that the portable POS terminal attempts to communicate with is in an unusable state are explained above. Such an embodiment is not limited to this. 
     For example, in the embodiment, the position measurement tag  80  is attached to each of the peripheral devices and a position coordinate is periodically measured. However, the measurement of a position coordinate may be unnecessary for a peripheral device used in a substantially fixed position. In other words, a position coordinate may be measured at a setting time of the peripheral device and stored and the stored position coordinate may be repeatedly used. 
     If displaying the guidance screen in Act  748 , the tablet  70  may emit alarm sound with the speaker  77  to call attention. 
     If the general-purpose tablet terminal functioning as the tablet  70  includes a microphone, the tablet  70  may be configured to be able to perform selection and instruction by voice without depending on the touch. 
     The portable POS terminal is not limited to the tablet PC and may be a notebook PC. The portable POS terminal may be a hand-held type POS terminal. However, the portable POS terminal may be a POS terminal of any form and shape so long as the portable POS terminal is a POS terminal that can be moved by or with a user by, for example, being carried by the user, attached to the user, or attached to a cart or the like moving with the user or any POS terminal that is not fixed but can be moved about in a store. 
     In the embodiment, a portable POS terminal and a checkout system are explained as examples. However, embodiments can also be applicable to other devices and systems. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the present disclosure. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.