Patent Publication Number: US-2023146356-A1

Title: Transmission device and communication system

Description:
TECHNICAL FIELD 
     The present disclosure relates to a transmission device and a communication system that can resume data communication after the data communication is interrupted and is recovered. 
     BACKGROUND ART 
     In some existing communication systems, a transmission device first transmits a transmission-scheduled data list of transmission data to a reception device, and then performs data communication. In such a communication system, when the data communication is interrupted by some communication failure, the communication system cannot determine, of data listed in the transmission-scheduled data list, which data has been transmitted in communication (for example, see Patent Literature 1). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2007-174247 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the existing communication system using the transmission-scheduled data list, if the data communication is interrupted, the transmission device performs transmission from first transmission data of the transmission-scheduled data list, or performs transmission from transmission data of the transmission-scheduled data list designated by a user in a reception device. 
     Therefore, in the existing communication system, the communication volume of transmission data is increased and communication time of transmission data is long. 
     The present disclosure is made in consideration of the above circumstances, and relates to a transmission device and a communication system that can reduce, even if data communication is interrupted, the communication volume of transmission data in re-transmission, and reduce a communication time necessary for the re-transmission. 
     Solution to Problem 
     A transmission device according to an embodiment of the present disclosure includes: a communication module configured to communicate with a reception device through transmission of data; and a controller configured to process data that is transmitted in communication between the communication module and the reception device. The controller is configured to extract data from transmission-scheduled data and produce a transmission-scheduled data list. The controller is configured to acquire from the reception device, when data communication between the transmission apparatus and the reception device is interrupted and is then recovered, and an interruption history of the communication is present in the reception device, an unreceived data list indicating data that is not received by the reception device before the communication is interrupted. The controller is configured to combine the acquired unreceived data list with the produced transmission-scheduled data list to update the transmission-scheduled data list. The communication module is configured to transmit the updated transmission-scheduled data list to the reception device, and transmit the transmission-scheduled data corresponding to the transmission-scheduled data list to the reception device after transmitting the updated transmission-scheduled data list. 
     Advantageous Effects of Invention 
     According to the embodiment of the present disclosure, the controller produces the transmission-scheduled data list from data to be transmitted. When data communication is interrupted and is then recovered, and the interruption history of the communication is present in the reception device, the controller acquires, from the reception device, the unreceived data list indicating data that is not received by the reception device before the communication is interrupted. The controller combines the acquired unreceived data list with the produced transmission-scheduled data list to update the transmission-scheduled data list. Furthermore, the controller transmits the transmission-scheduled data corresponding to the transmission-scheduled data list to the reception device, after transmitting the updated transmission-scheduled data list to the reception device. As a result, even in the case where data communication between the transmission device and the reception device is interrupted, the controller can transmit the transmission-scheduled data in the middle of the data communication, since the updated transmission-scheduled data list can be used. Therefore, the transmission device can reduce the communication volume of transmission data related to re-transmission, and can reduce the communication time necessary for the transmission data related to the re-transmission. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram illustrating a data acquisition device and an air-conditioning apparatus in a communication system according to an embodiment 
         FIG.  2    is a diagram to explain functions of a controller of the data acquisition device in the communication system according to the embodiment. 
         FIG.  3    is a diagram to explain functions of a controller of the air-conditioning apparatus in the communication system according to the embodiment. 
         FIG.  4    is a flowchart to explain operation of the data acquisition device in the communication system according to the embodiment. 
         FIG.  5    is a flowchart to explain operation of the air-conditioning apparatus in the communication system according to the embodiment. 
         FIG.  6    is a diagram to explain data flow between the data acquisition device and the air-conditioning apparatus in the communication system according to the embodiment. 
         FIG.  7    is a diagram illustrating data stored in a memory of the controller of the air-conditioning apparatus in the communication system according to the embodiment, 
         FIG.  8    is a diagram illustrating a transmission-scheduled data list created by a list data extraction module of the air-conditioning apparatus in the communication system according to the embodiment. 
         FIG.  9    is a diagram illustrating a transmission-scheduled data list of Modification 1 created by the list data extraction module of the air-conditioning apparatus in the communication system according to the embodiment. 
         FIG.  10    is a diagram illustrating a transmission-scheduled data list of Modification 2 created by the list data extraction module of the air-conditioning apparatus in the communication system according to the embodiment. 
         FIG.  11    is a diagram illustrating a transmission-scheduled data list of Modification 3 created by the list data extraction module of the air-conditioning apparatus in the communication system according to the embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A communication system according to an embodiment will be described with reference to the drawings. It should be noted that in each of figures, components that are the same as those in a previous figure or previous figures are denoted by the same reference sings, and numerals in the drawings, and after they are each described once, their descriptions will not be re-applied, except for when the necessity arises, The present disclosure can include all possible combinations of configurations described regarding the following embodiment. 
     Embodiment 
       FIG.  1    is a diagram illustrating a data acquisition device  101  and an air-conditioning apparatus  102  in a communication system  100  according to the embodiment. 
     As illustrated in  FIG.  1   , the communication system  100  includes the data acquisition device  101  and the air-conditioning apparatus  102 . 
     The data acquisition device  101  is an information terminal such as a smartphone, a desktop PC, a notebook PC, and a tablet PC. 
     The air-conditioning apparatus  102  transmits data to the data acquisition device  101 . 
     The air-conditioning apparatus  102  is a transmission apparatus that transmits data, and the data acquisition device  101  is a reception device that receives the data from the air-conditioning apparatus  102 . 
     In communication between the data acquisition device  101  and the air-conditioning apparatus  102 , a transmission and reception data list  103  is transmitted between the data acquisition device  101  and the air-conditioning apparatus  102 . The transmission and reception data list  103  includes a transmission-scheduled data list  801  (see  FIG.  8   ) extracted and produced from data on the air-conditioning apparatus  102 , and an unreceived data list  207 _ 2  (see  FIG.  2   ) in the data acquisition device  101 . 
     Furthermore, the air-conditioning apparatus  102  transmits various kinds of data  104  to the data acquisition device  101 . The various kinds of data  104  are, for example, a data acquisition date and time, an indoor temperature, an external air temperature, an opening degree of a LEV (expansion valve), a pipe temperature at a heat exchanger, a discharge pressure, a suction pressure, a discharge temperature, a suction temperature at a compressor, and parameters of subcooling and superheating. 
       FIG.  2    is a diagram for explanation of functions of a controller  201  of the data acquisition device  101  in the communication system  100  according to the embodiment. 
     As illustrated in  FIG.  2   , the controller  201  of the data acquisition device  101  is connected to an input module  200  and a memory  207 . 
     The input module  200  is a device that does input to the data acquisition device  101 , and for example, a touch panel or a mouse. 
     The memory  207  stores communication history data  207 _ 1 , the unreceived data list  207 _ 2 , various kinds of data  207 _ 3  received from the air-conditioning apparatus  102 , etc. The communication history data  207 _ 1  is data indicating a communication history at time at which communication is interrupted, and is recorded for each data. The unreceived data list  207 _ 2  indicates data that has not yet been received by the data acquisition device  101 . 
     The controller  201  includes a data operation reception module  202 , a data transmission request module  203 , an external communication module  204 , a list data collation module  205 , a list data extraction module  206 , a communication history management module  208 , and an acquired data management module  209 . 
     The data operation reception module  202  receives a request for data transmission that is input from the input module  200 . 
     The data transmission request module  203  makes the request for data transmission that is received by the data operation reception module  202  to the external communication module  204 . 
     The external communication module  204  transmits data such as the unreceived data list  207 _ 2 , the transmission-scheduled data list  801 , and the various kinds of data  104  to the air-conditioning apparatus  102 , and in addition, transmits the request for data transmission from the data transmission request module  203 , etc. to the air-conditioning apparatus  102 . 
     The list data extraction module  206  extracts only data to be listed, from received data stored in the memory  207  (see  FIG.  8   ). 
     The list data collation module  205  collates list items of the unreceived data list  207 _ 2  and list items of the transmission-scheduled data list  80  transmitted from the air-conditioning apparatus  102  with each other. 
     The acquired data management module  209  stores in the memory  207 , various kinds of data acquired from the air-conditioning apparatus  102  via the external communication module  204 . 
     The communication history management module  208  stores in the memory  207 , a communication history at time at which communication is interrupted. 
       FIG.  3    is a diagram for explanation of functions of a controller  301  of the air-conditioning apparatus  102  in the communication system  100  according to the embodiment. 
     Referring to  FIG.  3   , the controller  301  of the air-conditioning apparatus  102  includes an external communication module  302 , a list data collation module  303 , a list data extraction module  304 , a memory  305 , a data acquisition module  306 , a clock module  307 , a communication history management module  308 , and an acquired data management module  309 . 
     As illustrated in  FIG.  3   , the controller  301  is connected to a sensor  1   a,  a sensor  1   b , . . . , and a sensor  1   n.    
     The clock module  307  outputs time to be referred to in order that data from the sensor  1   a,  the sensor  1   b , . . . , and the sensor  1   n  be provided as time-series data. 
     The data acquisition module  306  acquires various kinds of data from the sensor  1   a,  the sensor  1   b , . . . , and the sensor  1   n , and the time from the dock module  307 . 
     The memory  305  stores the time acquired from the dock module  307  and the various kinds of data acquired by the data acquisition module  306 , on a time series basis. 
     The list data extraction module  304  acquires data for the transmission-scheduled data list  801 , from the various kinds of data stored in the memory  305 , and produces the transmission-scheduled data list  801 . 
     The list data collation module  303  collates list items of the transmission-scheduled data list  801  produced by the list data extraction module  304  and list items of the unreceived data list  207 _ 2  received from the data acquisition device  101  with each other. 
     The external communication module  302  transmits the unreceived data list  207 _ 2 , the transmission-scheduled data list  801 , the various kinds of data  104 , etc., to the data acquisition device  101 . The communication history management module  308  stores in the memory  305 , a communication history at time at which the communication is interrupted. 
     The acquired data management module  309  transfers the various kinds of data  104  stored in the memory  305  to the external communication module  302 . 
     It should be noted that the controller  301  as illustrated in  FIG.  3    is dedicated hardware or a central processing unit (CPU, also referred to as a central processing device, a processing device, an arithmetic device, a microprocessor, a microcomputer, or a processor) that executes a program stored in a memory. In the case where the controller  301  is the dedicated hardware, the controller  301  corresponds to, for example, a single circuit, a composite circuit, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a combination thereof. Functional modules whose functions are fulfilled by the controller  301  may be respective hardware, or may be single hardware. In the case where the controller  301  is the CPU, functions that are fulfilled by the controller  301  are fulfilled by software, firmware, or a combination of software and firmware. The software and the firmware are written as programs and stored in the memory  305 . The CPU fulfills the functions of the controller  301  by reading out and executing the programs stored in the memory  305 . The memory is, for example, a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, and an EEPROM. It should be noted that part of the functions of the controller  301  may be fulfilled by dedicated hardware, and the other part of the functions may be fulfilled by software or firmware. 
     Next, an operation of the communication system  100  according to the embodiment will be described.  FIG.  4    is a flowchart for explanation of an operation of the data acquisition device  101  in the communication system  100  according to the embodiment.  FIG.  5    is a flowchart for explanation of an operation of the air-conditioning apparatus  102  in the communication system  100  according to the embodiment.  FIG.  6    is a diagram for an explanation of the flow of data between the data acquisition device  101  and the air-conditioning apparatus  102  in the communication system  100  according to the embodiment. 
     First of all, an operation of the data acquisition device  101  will be described with reference to  FIG.  4   . 
     As illustrated in  FIG.  4   , the controller  201  of the data acquisition device  101  establishes communication with the air-conditioning apparatus  102  (step S 400 ), and then checks an interruption history in previous data reception on the basis of the communication history data  207 _ 1  stored in the memory  207  (step S 401 ). 
     Subsequently, the controller  201  determines whether or not an interruption history is present for each of data in the previous data reception (step S 402 ). When the controller  201  determines in step S 402  that an interruption history in the previous data reception is present (YES in step S 402 ), the controller  201  reads the unreceived data list  207 _ 2  prior to interruption, which is stored in the memory  207  (step S 414 ). Of the read unreceived data list  207 _ 2  prior to the interruption, unreceived data list  207 _ 2  including data the communication history of which includes record of “failure” is transmitted from the controller  201  to the air-conditioning apparatus  102  (step S 415 ). 
     In contrast, when determining in step S 402  that an interruption history in the previous data reception is absent (NO in step S 402 ), the controller  201  issues a request for data transmission to the air-conditioning apparatus  102  (step S 403 ). 
     After step S 403 , after step S 415 , or after it is determined that the answer to the question in step S 412  is YES, the controller  201  acquires the transmission-scheduled data list  801  from the air-conditioning apparatus  102  (step S 404 ). 
     Subsequently, the controller  201  removes received data from the unreceived data list  207 _ 2  stored in the memory  207  of the data acquisition device  101 , thereby updating the unreceived data list  207 _ 2  (step S 405 ). 
     The controller  201  transmits the updated unreceived data list  207 _ 2  to the air-conditioning apparatus  102  (step S 406 ). Then, the controller  201  receives data corresponding to the transmitted unreceived data list  207 _ 2 , from the air-conditioning apparatus  102  (step S 407 ). 
     Thereafter, the controller  201  deletes a list corresponding to the received data, from the unreceived data list  207 _ 2  (step S 408 ). 
     Subsequently, the controller  201  determines whether data communication is interrupted by a communication failure or not (step S 409 ). When determining in step S 409  that data communication is interrupted by a communication failure (YES in step S 409 ), the controller  201  temporarily saves in the memory  207 , an unreceived data list  207 _ 2  reflecting the above determination (step S 416 ). Next, the controller  201  records “success” or “failure” as a communication state for each data, in the unreceived data list  207 _ 2  as in a transmission-scheduled data list  801 _ 1  as indicated in  FIG.  8    (step S 417 ). 
     Thereafter, the controller  201  is caused to be on standby for a predetermined time until communication is recovered (step S 418 ), and determines whether the communication is recovered or not (step S 419 ). When the controller  201  determines in step S 419  that the communication is recovered (YES in step S 419 ), the processing returns to step S 401 . By contrast, when determining in step S 419  that the communication is not recovered (NO in step S 419 ), the controller  201  interrupts the data reception (step S 420 ), and ends data transmission (step S 413 ). It should be noted that the data to be received is the various kinds of data  104  from the air-conditioning apparatus  102 . 
     In contrast, when determining in step S 409  that data communication is not interrupted by a communication failure (NO in step S 409 ), the controller  201  completes transmission of the transmission-scheduled data (step S 410 ), and acquires the transmission-scheduled data list  801  from the air-conditioning apparatus  102  (step S 411 ). 
     Then, the controller  201  determines whether or not the transmission-scheduled data list  801  and the unreceived data list  207 _ 2  of the data acquisition device  101  are not different from each other (step S 412 ). When the controller  201  determines in step S 412  that the transmission-scheduled data list  801  and the unreceived data list  207   2  of the data acquisition device  101  are not different from each other (YES in step S 412 ), the processing returns to step S 404 . By contrast, when determining that the transmission-scheduled data list  801  and the unreceived data list  207 _ 2  of the data acquisition device  101  are different from each other (NO in step S 412 ), the controller  201  ends the data transmission (step S 413 ). 
     Next, an operation of the air-conditioning apparatus  102  will be described with reference to  FIG.  5   . 
     As illustrated in  FIG.  5   , the controller  301  of the air-conditioning apparatus  102  establishes communication with the data acquisition device  101  (step S 500 ), and then acquires various kinds of data from the sensor  1   a,  the sensor  1   b,  . . . , and the sensor  1   n,  and also acquires the time from the dock module  307  (step S 501 ). 
     In  FIG.  6   , communication establishment at timing T 1  corresponds to step S 400  in  FIG.  4    and step S 500  in  FIG.  5   . Request for data transmission at timing T 2  corresponds to step S 403  in  FIG.  4    and step S 505  in  FIG.  5   . Transmission of a transmission-scheduled data list at timing T 3  corresponds to step S 404  in  FIG.  4    and step S 508  in  FIG.  5   . Transmission of an unreceived data list at timing T 4  corresponds to step S 406  in  FIG.  4    and step S 509  in  FIG.  5   . Transmission of untransmitted data ( 1 /n) at timing T 5  corresponds to step S 407  in  FIG.  4    and step S 510  in  FIG.  5   . Request for untransmitted data ( 2 /n) at timing T 6  corresponds to step S 406  in  FIG.  4    and step S 509  in  FIG.  5   . Resumption of communication at timing T 7  corresponds to step S 419  in  FIG.  4    and step S 522  in  FIG.  5   . Request for data transmission at timing T 8  corresponds to step S 403  in  FIG.  4    and step S 505  in  FIG.  5   . Transmission of a transmission-scheduled data list at timing T 9  corresponds to step S 404  in  FIG.  4    and step S 508  in  FIG.  5   . Transmission of an unreceived data list at timing T 10  corresponds to step S 406  in  FIG.  4    and step S 509  in  FIG.  5   . Transmission of untransmitted data (n/n) at timing T 11  corresponds to step S 407  in  FIG.  4    and step S 510  in  FIG.  5   . Completion of reception at timing T 12  corresponds to step S 412  in  FIG.  4    and step S 513  in  FIG.  5   . End of transmission and reception at timing T 13  corresponds to step S 413  in  FIG.  4    and step S 518  in  FIG.  5   . 
     Next, the controller  301  stores in the memory  305 , the various kinds of data and the time acquired in step S 501 , on a time-series basis (step S 502 ). 
       FIG.  7    is a diagram illustrating the data stored in the memory  305  of the controller  301  of the air-conditioning apparatus  102  in the communication system  100  according to the embodiment. As illustrated in  FIG.  7   , in the data stored in the memory  305 , to dates, respective numbers are assigned. For a plurality of pieces of data acquired at the same date, respective times are indicated, The plurality of pieces of data are stored on a time-series basis. In  FIG.  7   , temperature_1, temperature _2, measured value_1, . . . are indicated as acquired data.  FIG.  7    is a diagram indicating the entire data transmitted between the data acquisition device  101  and the air-conditioning apparatus  102 . 
     The controller  301  acquires data for the transmission-scheduled data list  801  from the various kinds of data stored in the memory  305  (step S 503 ), and produces the transmission-scheduled data list  801  indicating data to be transmitted (step S 504 ). Then, the controller  301  receives a request for data transmission from the data acquisition device  101  (step S 505 ). 
       FIG.  8    is a diagram illustrating the transmission-scheduled data list  801  produced by the list data extraction module  304  of the air-conditioning apparatus  102  in the communication system  100  according to the embodiment. As illustrated in  FIG.  8   , in the transmission-scheduled data list  801 , numbers, dates, and times are indicated as data listed from the entire data as illustrated in  FIG.  7   . To the dates, the respective numbers are assigned. For the pieces of data, the respective times are indicated. transmission-scheduled data list  801 _ 1  is obtained by adding an item  802  indicating a communication state, to the transmission-scheduled data list  801 . In the item  802 , a communication state is written as data by the communication history management module  308  when the data communication is interrupted. 
     Next, the controller  301  checks a previous communication interruption history from the data acquisition device  101  (step S 506 ). The controller  301  determines whether or not the previous communication interruption history is present (step S 507 ). 
     When determining in step S 507  that the previous communication interruption history is present (YES in step S 507 ), the controller  301  acquires unreceived data prior to interruption of the communication, from the data acquisition device  101  (step S 519 ). 
     Thereafter, the controller  301  combines the transmission-scheduled data list  801  and the unreceived data list  207 _ 2  to update the transmission-scheduled data list  801  (step S 520 ). The unreceived data list  207 _ 2  includes only data that is not received by the data acquisition device  101 . 
     When the result of the determination in step S 507  is NO, when the transmission-scheduled data list  801  is updated in step S 520 , and when the result of the determination in step S 516  is NO, the controller  301  transmits the transmission-scheduled data list  801  to the data acquisition device  101  (step S 508 ). 
     Thereafter, the controller  301  receives data transmitted from the data acquisition device  101  (step S 509 ). 
     Next, the controller  301  starts transmission of transmission-scheduled data corresponding to the transmission-scheduled data list  801  or the updated transmission-scheduled data list  801  (step S 510 ). 
     Thereafter, the controller  301  deletes a list corresponding to the transmitted data from the transmission-scheduled data list  801  (step S 511 ). 
     Subsequently, the controller  301  determines whether or not data communication is interrupted by a communication failure (step S 512 ). When determining that data communication is interrupted by a communication failure (YES in step S 512 ), the controller  301  is caused to be on standby for a predetermined time until the communication is recovered (step S 521 ), and determines whether or not the communication is recovered (step S 522 ), When the controller  301  determines in step S 522  that the communication is recovered (YES in step S 522 ), the processing returns to step S 500 . By contrast, when the controller  301  determines that the communication is not been recovered (NO in step S 522 ), the controller  301  interrupts the data transmission (step S 523 ), and ends the processing. 
     By contrast, when determining that data communication is not interrupted by a communication failure (NO in step S 512 ), the controller  301  completes transmission of the transmission-scheduled data corresponding to the transmission-scheduled data list  801  or the updated transmission-scheduled data list  801  (step S 513 ). 
     Thereafter, the controller  301  acquires the unreceived data list  207 _ 2  from the data acquisition device  101  (step S 514 ). The structure of the unreceived data list  207 _ 2  is the same as that of each of the transmission-scheduled data list  801 _ 1 , a transmission-scheduled data list  901 _ 1 , a transmission-scheduled data list  1001 _ 1 , and a transmission-scheduled data list  1101 _ 1 , and is a list structure in which a transmission and reception structure is recorded. Subsequently, the controller  301  collates the transmission-scheduled data list  801  or the updated transmission-scheduled data list  801  with the unreceived data list  207 _ 2  (step S 515 ). 
     Next, the controller  301  determines whether or not the transmission-scheduled data list  801  is not different from the unreceived data list  207 _ 2  from the data acquisition device  101  (step S 516 ). When determining that the transmission-scheduled data list  801  is not different from the unreceived data list  207 _ 2  from the data acquisition device  101  (YES in step S 516 ), the controller  301  ends the data transmission (step S 518 ). 
     By contrast, when determining that the transmission-scheduled data list  801  is different from the unreceived data list  207 _ 2  from the data acquisition device  101  (NO in step S 516 ), the controller  301  reflects different part between those data lists in the transmission-scheduled data list  801 , thereby updating the transmission-scheduled data list  801  (step S 524 ), and the processing then returns to step S 508 . 
     Modification 1 
     As the transmission-scheduled data list, a transmission-scheduled data list  901  as illustrated in  FIG.  9    may be used instead of the transmission-scheduled data list  801  as illustrated in  FIG.  8   .  FIG.  9    is a diagram illustrating the transmission-scheduled data list  901  of Modification 1 that is produced by the list data extraction module  304  of the air-conditioning apparatus  102  in the communication system  100  according to the embodiment. 
     As illustrated in  FIG.  9   , in the transmission-scheduled data list  901 , numbers and dates are indicated as data pieces which are obtained at intervals of sampling of various kinds of data, The transmission-scheduled data list  901 _ 1  is obtained by adding an item  902  indicating a communication state, to the transmission-scheduled data list  901 . In the item  902 , a communication data is written by the communication history management module  308  when data communication is interrupted. 
     Modification 2 
     As the transmission-scheduled data list, a transmission-scheduled data list  1001  as illustrated in  FIG.  10    may be used instead of the transmission-scheduled data list  801  as illustrated in  FIG.  8   .  FIG.  10    is a diagram illustrating a transmission-scheduled data list  1001  of Modification 2 that is produced by the list data extraction module  304  of the air-conditioning apparatus  102  in the communication system  100  according to the embodiment. 
     As illustrated in  FIG.  10   , unlike the transmission-scheduled data list  801  as illustrated in  FIG.  8   , in the transmission-scheduled data list  1001 , for data, respective dates are indicated; that is, to the data, respective numbers are not assigned. The transmission-scheduled data list  1001 _ 1  is obtained by adding an item  1002  indicating a communication state, to the transmission-scheduled data list  1001 . In the item  1002 , a communication state is written by the communication history management module  308  when data communication is interrupted. The transmission-scheduled data list  1001  having such a structure can be used in the case where the number of management target devices is one. It should be noted that in place of a numerical value, for example, a unit number or a model number can be used as the number. 
     Modification 3 
     As the transmission-scheduled data list, a transmission-scheduled data list  1101  as illustrated in  FIG.  11    may be used as the transmission-scheduled data list  901  as illustrated in  FIG.  9   .  FIG.  11    is a diagram illustrating the transmission-scheduled data list  1101  of Modification 3 that is produced by the list data extraction module  304  of the air-conditioning apparatus  102  in the communication system  100  according to the embodiment. 
     As illustrated in  FIG.  11   , unlike the transmission-scheduled data list  901  as illustrated in  FIG.  9   , in the transmission-scheduled data list  1101 , for data, respective dates are indicated; that is, to the data, respective numbers are not assigned. The transmission-scheduled data list  1101 _ 1  is obtained by adding an item  1102  indicating a communication state, to the transmission-scheduled data list  1001 . In the item  1102 , a communication state is written by the communication history management module  308  when data communication is interrupted. The transmission-scheduled data list  1101  having such a structure can be used in the case where the number of management target devices is one, as well as the transmission-scheduled data list  1001  as illustrated in  FIG.  10   . It should be noted that in place of a numerical value, for example, a unit number or a model number can be used as the number. 
     Therefore, even in the case where data communication is interrupted, the air-conditioning apparatus  102  in the communication system  100  according to the embodiment can transmit the transmission-scheduled data in the middle of the data communication since the air-conditioning apparatus  102  can use the updated transmission-scheduled data list  801 . Thus, the communication system  100  can reduce the communication volume of transmission data, and can reduce the communication time necessary for the transmission data. 
     It should be noted that the air-conditioning apparatus  102  of the embodiment is also referred to as a transmission device, and the data acquisition device  101  of the embodiment is also referred to as a reception device. 
     The configurations, etc. of the embodiment are described above by way of example, and these descriptions are not intended to limit the scope of the claims. The embodiment can be put to practical use in various configurations other than the above described ones, and various omissions, substitutions, and modifications can be made without departing from the gist of the embodiment. These configurations and the modifications thereof are covered in the scope and the gist of the embodiment. 
     Reference Signs List 
       1   a,    1   b,    1   n : sensor,  100 : communication system,  101 : data acquisition device,  102 : air-conditioning apparatus,  103 : transmission and reception data list,  104 : various kinds of data,  200 : input module,  201 : controller,  202 : data operation reception module,  203 : data transmission request module,  204 : external communication module,  205 : list data collation module,  206 : list data extraction module,  207 : memory,  207 _ 1 : communication history data,  207 _ 2 : unreceived data list,  207 _ 3 : various kinds of data,  208 : communication history management module,  209 : acquired data management module,  301 : controller,  302 : external communication module,  303 : list data collation module,  304 : list data extraction module,  305 : memory,  306 : data acquisition module,  307 : clock module,  308 : communication history management module,  309 : acquired data management module,  801 ,  801 _ 1 ,  901 ,  901 _ 1 ,  1001 ,  1001 _ 1 ,  1101 ,  1101 _ 1 : transmission-scheduled data list,  802 ,  902 ,  1002 ,  1102 : item