Patent Publication Number: US-2011054843-A1

Title: Diagnostic system and method for home appliance

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Korean Patent Application No. 10-2009-0071044, filed on Jul. 31, 2009 in the Korean Intellectual Property Office, and U.S. Provisional Patent Application No. 61/230,623 filed on Jul. 31, 2009 in the USPTO, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a diagnostic system and method for a home appliance, and more particularly to a home appliance diagnostic system and method for performing state inspection and fault diagnosis of a home appliance based on product information of the home appliance, which is output as a sound signal, to facilitate after-sale service for the home appliance. 
     2. Description of the Related Art 
     In operation, a home appliance stores values set for execution of the operation, information generated during the operation, fault information, etc. Particularly, in the event of a fault, the home appliance outputs a predetermined alarm, thereby enabling the user to recognize the state of the home appliance. The home appliance may output detailed fault information through its output device, for example, a display device or lamp, as well as simply notifying the user of completion of an operation or occurrence of a fault. 
     On the other hand, in the event of a fault in the home appliance, the user may utilize an after-sale service of calling a service center to ask advice on the state of the home appliance or request a service technician for the home appliance. 
     In this case, the home appliance generally outputs fault information simply or as a code value that cannot be understood by the user. For this reason, the user may have difficulty in coping with the fault in the home appliance and in accurately communicating the state of the home appliance to the service center even though contacting the service center. Consequently, when a service technician visits the user&#39;s home, a lot of time and cost may be taken for the service technician to repair the home appliance due to lack of accurate prior knowledge as to the state of the home appliance. For example, provided that a part required for repair of the home appliance is not prepared in advance, the service technician will have the inconvenience of re-visiting the user&#39;s home, resulting in an increase in repair time. 
     In order to solve the above problem, the home appliance may be connected to a server of the service center via a communication unit. However, in this case, it is necessary to construct a communication network. 
     With technological development, a fault may be remotely diagnosed over a telephone network. 
     European Patent No. 0510519 discloses a technique for transmitting fault information of a home appliance to a service center via a modem connected to the home appliance over a telephone network. However, this technique requires continuous connection of the modem to the home appliance. Particularly, in the case where the home appliance is a laundry treatment machine that is usually installed outdoors, a spatial restriction may be imposed on connecting the laundry treatment machine to the telephone network. 
     U.S. Pat. No. 5,987,105 discloses a technique for converting fault information of a home appliance into a sound signal of an audible frequency band and transmitting the sound signal to a service center over a telephone using a telephone network. Signal interference may occur depending on an ambient environment in the course of converting the fault information of the home appliance into the sound signal of the audible frequency band and then transmitting the sound signal to a receiver of the telephone. In addition, data may be lost according to characteristics of the telephone network during the transmission of the sound signal over the telephone network. 
     In the case of U.S. Pat. No. 5,987,105 described above, the size of one symbol representing 1 bit which is one information unit is 30 ms and an independent frequency is used for each bit in order to prevent data loss and to correctly communicate product information. 
     However, the conventional system has suggested no detailed scheme for performing diagnosis on the state of the home appliance. 
     There is a need to suggest a detailed scheme not only for outputting product information using a sound signal but also for performing fault diagnosis using data included in the product information. 
     SUMMARY OF THE INVENTION 
     Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a home appliance for outputting a sound signal including product information to facilitate fault diagnosis using the sound signal, and a diagnostic system for the home appliance. 
     It is another object of the present invention to provide a diagnostic system and method for a home appliance wherein the state of the home appliance is determined and a fault thereof is diagnosed using product information extracted from an output sound signal to achieve correct fault diagnosis for the home appliance and also to enable rapid after-sale service for the home appliance. 
     In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a diagnostic method for a home appliance diagnostic system, the method including receiving a sound signal output from a home appliance and extracting product information about the home appliance from the sound signal, analyzing the product information and determining, when an error code is set in the product information, whether the error code corresponds to a drainage error associated with a drainage operation of the home appliance, diagnosing fault of the home appliance by determining, when the error code corresponds to the drainage error, at least one of whether bubbles have been generated, whether program malfunction has occurred, and whether drainage malfunction has occurred using diagnostic data associated with the drainage operation among a plurality of diagnostic data included in the product information, and deriving a diagnosis result by deriving a solution corresponding to a cause of the drainage error, the cause being obtained according to the fault diagnosis. 
     In accordance with another aspect of the present invention, there is provided a home appliance diagnostic system including a home appliance for outputting product information required for fault diagnosis as a sound signal, a diagnostic server for receiving the sound signal, deriving a state, a fault, and a fault cause of the home appliance, and deriving, as a diagnosis result, a solution to the fault, and a portable terminal for receiving the sound signal output from the home appliance and transmitting the sound signal to the diagnostic server through a communication network, wherein the diagnostic server determines, when an error code is set in the product information extracted from the received sound signal, whether the error code corresponds to a drainage error associated with a drainage operation of the home appliance based on the product information, and diagnoses fault of the home appliance by determining, when the error code corresponds to the drainage error, at least one of whether bubbles have been generated, whether program malfunction has occurred, and whether drainage malfunction has occurred using diagnostic data associated with the drainage operation among a plurality of diagnostic data included in the product information, and then derives a solution to a cause of the drainage error. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic view showing the configuration of a home appliance diagnostic system according to an embodiment of the present invention; 
         FIG. 2  is a perspective view showing the configuration of a home appliance according to an embodiment of the present invention; 
         FIG. 3  is a block diagram showing a configuration for control of a home appliance in the home appliance diagnostic system of  FIG. 1 ; 
         FIG. 4  is a block diagram of a diagnostic server of a service center in the home appliance diagnostic system illustrated in  FIG. 1 ; 
         FIG. 5  is a flow chart illustrating a diagnostic method for a home appliance diagnostic system according to the present invention; 
         FIG. 6  is a flow chart illustrating a diagnostic method using product information in a home appliance diagnostic system of the present invention; 
         FIG. 7  is a flow chart illustrating another diagnostic method using product information in a home appliance diagnostic system of the present invention; and 
         FIG. 8  illustrates exemplary fault diagnosis results using product information in a home appliance diagnostic system of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same, or like parts. 
       FIG. 1  is a schematic view showing the configuration of a home appliance diagnostic system according to an embodiment of the present invention. 
     Referring to  FIG. 1 , a home appliance of the present invention is configured in such a manner that, when a home appliance  101  in each home outputs information about the operation thereof in the form of a sound signal, the sound signal, which includes product information, is input to a portable terminal such as a mobile phone or a telephone and is then transmitted to a service center  200  over a telephone network so that a diagnostic server in the service center  200  may diagnose the state of the home appliance  101  to determine whether the home appliance  101  is out of order. 
     The home appliance diagnostic system includes the home appliance  101  and the service center  200  for monitoring the state of the home appliance  101  and diagnosing the fault of the home appliance  101 . The service center  200  includes the diagnostic server having home appliance information and a diagnosis program. 
     The home appliance  101  includes a display device  118  for displaying predetermined data. The display device is a light emitter such as a light emitting diode (LED), a liquid crystal display (LCD) or an organic electro-luminescent (EL) display, and visually displays state information or fault information of the home appliance  101 . The home appliance  101  further includes a sound output device  160  for outputting a sound signal. The sound output device  160  reproduces and outputs information about the operation, state or fault of the home appliance  101  as a predetermined sound signal. 
     When the home appliance  101  malfunctions or operates abnormally, it notifies the user of occurrence of a fault by outputting an error code through the display device  118  or outputting an alarm sound through the sound output device  160  (S 1 ). 
     Here, the home appliance  101  stores product information including operation information, fault information, and user information. 
     The user confirms information of the home appliance  101  displayed on the display device of the home appliance  101  and then controls the operation of the home appliance  101  or requests repair of the home appliance  101  from the service center  200 . At this time, the user may contact the service center  200  to notify the service center  200  that a fault has occurred in the home appliance  101  and ask advice on the fault (S 2 ). 
     In the case where the user connects to the service center  200  and manipulates a selector (not shown) of an input device (not shown) in the home appliance  101  in response to a request from the service center  200  (S 3 ), the home appliance  101  converts the product information into a predetermined sound signal and outputs the sound signal through the sound output device  160 . The sound signal including the product information, output in this manner, is transmitted to the service center  200  over a communication network (S 4 ). 
     At this time, the user may notify the service center  200  of model information and fault symptoms of the home appliance  101  and place a portable terminal  80  such as a mobile phone or a telephone close to a sounding portion of the home appliance  101 , that is, the sound output device  160  during the call with the service center  200  to transmit the sound signal including the product information of the home appliance  101  to the service center  200 . In this manner, the user may transmit the sound signal including the product information of the home appliance  101  to the service center  200  using portable terminal  80  such as a telephone or a mobile phone to request an after-sale service (A/S) for the home appliance  101 . 
     The service center  200  receives the sound signal output from the home appliance  101  over a communication network connected thereto, for example, a telephone network, and checks the product state of the home appliance  101  based on the received sound signal to diagnose whether the home appliance  101  is out of order (S 5 ). 
     Based on a result of the diagnosis, the service center  200  dispatches a service technician  93  to the user&#39;s home to provide a service suitable for the product state and fault diagnosis of the home appliance  101  (S 6 ). In step S 6 , the diagnosis result may be transmitted to a terminal of the service technician  93  so that he/she may fix the home appliance  101 . 
     In addition, the service center  200  may connect with the user through the communication network to transmit the diagnosis result to the user in the form of a voice through a customer service agent or in the form of predetermined data (S 7 ). 
     Therefore, when the user connects to the service center  200  through a communication network, for example, a telephone network, the diagnostic system can accurately determine the state of the home appliance  101  based on a sound signal, thereby providing rapid service and also allowing the user to easily check the state of the home appliance. 
     Although the home appliance  101  of the present invention will hereinafter be described for illustrative purposes as being a laundry treatment machine, the present invention is not limited thereto. Rather, it is to be clearly understood that the present invention is applicable to all home appliances including TVs, air conditioners, refrigerators, electric rice cookers, and microwave ovens. In the following description, a telephone network or a mobile communication network is used as an example of the communication network and a telephone or a mobile phone is used as an example of the portable terminal  80 . 
     The home appliance  101  is constructed as described below to output product information as a sound signal. 
       FIG. 2  is a perspective view showing the configuration of a home appliance according to an embodiment of the present invention. 
     A description will hereinafter be given of a laundry treatment machine as an example of the home appliance. 
     Referring to  FIG. 2 , the laundry treatment machine  101 , which is the home appliance of the present invention, includes a cabinet  111 , a tub  122  disposed inside the cabinet  111  for washing laundry, a motor (not shown) for driving the tub  122 , a wash water supply (not shown) for supplying wash water to the tub  122 , and a drainage device (not shown) for draining the wash water externally after the laundry is washed. 
     The cabinet  111  includes a cabinet body  112 , a cabinet cover  113  coupled to a front side of the cabinet body  112 , a control panel  116  disposed over the cabinet cover  113  for controlling the operation of the laundry treatment machine  101 , and a top plate  115  disposed over the control panel  116  and coupled to the cabinet body  112 . The cabinet cover  113  includes a hole (not shown) for putting in or taking out the laundry therethrough, and a door  114  for pivotally moving to open/close the hole. 
     The control panel  116  is provided with an input device including a manipulator  117  having a plurality of manipulating keys for manipulating the laundry treatment machine  101 , a sound output device  160  for outputting a sound signal indicative of the operating state of the laundry treatment machine  101 , and a display device  118  for displaying the operating state of the laundry treatment machine  101  in the form of text, a numeral, a special symbol, an image, or the like. In the input device, the manipulator  117  may be configured with an input unit for applying a certain signal by push, contact, pressure, rotation, or the like, such as a key, a button, a switch, a rotary switch, or a touch input unit. 
     When the user has manipulated a selector in the control panel  116 , the laundry treatment machine  101  receives a smart diagnosis mode command and a signal output command, converts product information into a digital signal in a predetermined format, and provides the digital signal to a modulator (not shown). As the modulator operates according to the digital signal, a predetermined sound signal is output through the sound output device  160 . 
     The sound output device  160  is provided at a rear side of the control panel  116  to output a sound signal from the inside of the control panel  116 . The sound output device  160  is spaced apart from the manipulator  117 , a selector  130  or a sound output hole  119  by a predetermined distance so that it can be protected from water or foreign substances incoming from the outside. 
     The sound signal output from the sound output device  160  is externally emitted through cracks of portions of the control panel  116 , in which keys of the manipulator  117  or selector  130  are formed, along a sound path or sound guide portion formed at the rear side of the control panel  116 . Alternatively, in the case where the separate sound output hole  119  is provided, the sound signal output from the sound output device  160  may be externally emitted through the sound output hole  119 . 
     Here, it is preferable that the keys of the manipulator  117  or selector  130  be constructed so as to enlarge the gap between the control panel  116  and each of the keys or to permit an internal sound to be emitted externally when pressed. 
     The sound output device  160  may include at least one sound output device. 
     For example, in the case where the sound output device  160  includes two sound output devices, one of the sound output devices may output a sound signal of a combination of predetermined frequencies including product information of the home appliance and the other may output an effect sound or alarm sound of the home appliance and an indication sound indicative of the start or end of the output of the sound signal including the product information. 
     The sound signal output from the sound output device  160  is transmitted to the service center  200  through the portable terminal  80 , connected to a communication network. Here, the communication network may be, for example, a telephone network or mobile network, and the portable terminal  80  may be, for example, a telephone or mobile phone. 
     The service center  200 , which includes the diagnostic server, receives the sound signal output from the laundry treatment machine  101  and analyzes the received sound signal, so as to acquire operation information and fault information of the laundry treatment machine  101 . As a result, the service center  200  transmits a countermeasure against a faulty operation of the laundry treatment machine  101  to the user or dispatches a service technician to the user&#39;s home. 
       FIG. 3  is a block diagram showing a configuration for control of a home appliance in the home appliance diagnostic system of  FIG. 1 . 
     The home appliance  101  configured as stated above has a control configuration for performing a washing mode, a rinsing mode, a spin-drying mode, etc. for laundry within the home appliance  101 , processing data generated during the operation of the home appliance  101 , and, when a smart diagnosis mode is set based on an input of a selector, generating product information including data of the home appliance  101  in the form of a digital signal of a predetermined format and outputting a predetermined sound signal based on the digital signal. 
     Referring to  FIG. 3 , the home appliance  101  includes an input device  125 , a sensing device  170 , a memory  145 , a storage device  146 , a driver  180 , a modulator  150 , the sound output device  160 , and a controller  140  for controlling the entire operation of the home appliance  101 . 
     The input device  125  is provided with at least one input unit for inputting a predetermined signal or data to the home appliance  101  according to a user manipulation. The input device  125  includes the manipulator  117  and the selector  130 . 
     The selector  130  has at least one input unit. Upon selection of the smart diagnosis mode, the selector  130  applies a signal output command to the controller  140  so that product information is output in the form of a predetermined sound signal through the sound output device  160 . 
     The selector  130  may be provided with input units separate from those of the manipulator  117 . Alternatively, the manipulator  117  may include two or more input units that may operate or be recognized as the selector when manipulated simultaneously, or a specific input unit that may operate or be recognized as the selector when manipulated consecutively or for a predetermined time or more. 
     As the smart diagnosis mode is entered, the selector  130  turns on/off the sound output device  160 . That is, when the signal output command is input by the selector  130 , a digital signal including product information is output in the form of a predetermined sound signal in response to a control command from the controller  140 . At this time, the sound output device  160  operates to output the sound signal. 
     The manipulator  117  receives data such as an operation course or operation setting according to the operation of the home appliance  101  and applies the received data to the controller  140 . The manipulator  117  also receives settings related to sound signal output. That is, the manipulator  117  receives values for setting a sound signal output method, the level of a sound signal to be output, etc. 
     The input device  125  including the selector  130  and the manipulator  117  may be configured to include buttons, a dome switch, a touch pad (static pressure/capacitance), a jog wheel, a jog switch, a finger mouse, a rotary switch, a jog dial, or the like. Any device may serve as the input device  125  so long as it generates predetermined input data by a manipulation such as push, rotation, pressure or contact. 
     The sensing device  170  includes at least one sensor for sensing a temperature, a pressure, a voltage, current, the level of water, the number of rotations, or the like, and applies sensed or measured data to the controller  140 . For example, when water is supplied or drained to or from the laundry treatment machine, the sensing device  170  may measure the level of the water, the temperature of the supplied water, and the rotation speed of the tub or drum. The sensing device  170  includes at least one temperature sensing device (not shown). 
     The driver  180  controls driving of the home appliance  101  in response to a control command from the controller  140  such that the home appliance  101  performs a set operation. Therefore, the laundry treatment device washes laundry by performing a series of modes including a washing mode, a rinsing mode and a spin-drying mode. The driver  180  includes a motor controller (not shown) for applying an operation control signal to the motor. 
     For example, in the case of the laundry treatment machine, the driver  180  may drive a motor that rotates the tub or drum, and control the operation of the motor to wash soiled laundry through rotation of the tub or drum. Also, the driver  180  may control a valve in response to a control command from the controller  140  to supply or drain water. 
     The memory  145  stores control data for controlling the operation of the home appliance  101 , reference data used during the control operation of the home appliance, and the like. 
     The memory  145  includes all data storage units including a read only memory (ROM) or electrically erasable programmable ROM (EEPROM) for storing control data for the home appliance. The storage device  146  is a buffer for the controller  140  that temporarily stores data. The storage device  146  may be, for example, a dynamic random access memory (DRAM) or static RAM (SRAM). As needed, the storage device  146  may be incorporated into the controller  140  or memory  145 . 
     While the home appliance  101  performs a desired operation, the memory  145  stores operation information including operating state data generated during the operation and set data input by the manipulator  117  such that the home appliance  101  performs the desired operation, usage information including the number of occurrences of a specific operation in the home appliance  101  and model information of the home appliance  101 , and fault information including information about the cause or position of a fault when the home appliance  101  malfunctions. 
     The controller  140 , when a signal for smart diagnosis mode entry is input from the selector  130 , fetches product information stored in the memory  145  or storage device  146 , generates a digital signal of a predetermined format from the product information and applies the digital signal to the modulator  150 . Also, as the selector  130  is manipulated, the controller  140  controls the sound output device  160  to operate it. 
     The controller  140  includes a main controller  141  for controlling a flow of data being input or output to or from the home appliance  101 , generating and applying a control command based on data input from the sensing device  170 , or providing sensed data to the driver  180  to control the driver  180  to operate the home appliance  101 , and an encoder  142  for converting product information into a digital signal of a predetermined format in response to an input of the selector  130  such that a sound signal based on the digital signal is output. 
     The main controller  141 , when the smart diagnosis mode is entered in response to the input of the selector  130 , outputs a start sound indicating the start of the smart diagnosis mode through the sound output device  160  and displays predetermined data indicating the execution of the smart diagnosis mode through the display device  118 . 
     Also, when a digital signal generated by the encoder  142  is applied to the modulator  150  and a sound signal is thus output through the sound output device  160 , the main controller  141  controls the sound output device  160  to output a predetermined indication sound before and after the output of the sound signal. The indication sound before the output of the sound signal may be omitted as needed. 
     On the other hand, in the case where the sound output device  160  includes two or more sound output devices, the main controller  141  may control the sound output devices to output the indication sound and the sound signal including the product information through different ones of the sound output devices, respectively. 
     Upon entry into the smart diagnosis mode, the main controller  141  disables the manipulator  117  except for a power key and the selector  130  and controls the sensing device  170  and the driver  180  to make the home appliance  101  discontinue all other operations. 
     Also, when any one manipulating key of the manipulator  117  for setting of the operation of the home appliance  101  is input after power input, the main controller  141  does not start the smart diagnosis mode even though the selector  130  is input. Particularly, in the case where the selector  130  is not provided separately and an input of a combination of two or more of a plurality of manipulating keys of the manipulator  117  is recognized as the input of the selector  130 , the main controller  141  starts the smart diagnosis mode only when the selector  130  is input by a specified key combination immediately without any other input after the input of the power key. 
     That is, the setting of the operation of the home appliance by the manipulator  117  is considered to indicate that the user has no intention of entering the smart diagnosis mode, and the main controller  141  thus does not enter the smart diagnosis mode. Also, it is possible to prevent the smart diagnosis mode from being entered unnecessarily due to a faulty manipulation of the manipulator  117 . 
     The encoder  142  fetches the product information stored in the memory  145 , encodes the product information according to a predetermined encoding scheme and adds a preamble and an error check bit to the resulting data signal, so as to generate a digital signal of a predetermined format. The encoder  142  generates a digital signal consisting of a plurality of symbols by encoding the product information. 
     The encoder  142  encodes the product information using a bit error correction coding scheme to protect against data loss that may occur during transmission of the product information as a sound signal over the communication network. The encoder  142  uses a forward error correction (FEC) scheme as an example of the bit error correction coding scheme. The encoder  142  encodes the product information using convolutional coding. Thus, the diagnostic server of the service center  200  decodes the sound using a Viterbi decoding algorithm as the convolutional coding. 
     The encoder  142  performs such encoding based on a 1/2 code rate scheme, in which 2 bits are output for 1 bit input, or based on a 2/3 code rate scheme. In addition, the encoder  142  reduces the number of redundant bits using a puncturing algorithm. 
     The encoder  142  also performs bit interleaving against burst errors that may occur during data transmission. The encoder  142  performs bit interleaving on data on the basis of a predetermined number of bits, for example, 32 bits. That is, when the data is 60 bytes, the encoder  142  performs bit interleaving on data by permuting the data on a four by four byte basis according to a predetermined rule. 
     In the course of generating the digital signal, the encoder  142  may divide the digital signal into a plurality of frames by a predetermined size and packetize the frames into a packet. Also, the encoder  142  may set an inter-frame space (IFS) of a predetermined duration between adjacent ones of the frames of the digital signal. Also, during signal conversion, the encoder may set a dead time in a symbol in a period in which a data value is changed, in order to eliminate reverberation that affects the next signal conversion due to the principle of charging and discharging of a capacitor. 
     Assuming that the length of each of the symbols constituting the digital signal is a symbol time and the fundamental length of a frequency signal constituting the sound signal from the sound output device  160 , corresponding to each symbol, is also a symbol time, the encoder  142  may set a dead time within the symbol time with respect to one symbol. In this case, the length of the dead time varies with the length of the symbol time. 
     The product information includes operation information including operation settings, operating state data, etc., usage information, and fault information about a faulty operation, as stated above. The product information is data consisting of a combination of 0 s or 1 s, which is a digital signal of a format readable by the controller  140 . 
     The controller  140  generates a digital signal of a predetermined format by classifying data of the product information, incorporating specific data into the classified data and dividing the resulting data by a certain size or combining the resulting data, and applies the generated digital signal to the modulator  150 . 
     Also, the controller  140  may change the number of symbols corresponding to output frequency signals according to the number of frequencies used in the modulator  150 . 
     The modulator  150  applies a drive signal to the sound output device  160  in response to the digital signal from the controller  140  such that the sound output device  160  outputs a sound signal. The sound signal output in this manner includes product information. 
     The modulator  150  applies the drive signal to the sound output device  160  such that a specified frequency signal corresponding to one of the symbols constituting the digital signal is output for a symbol time. 
     The modulator  150  performs a control operation such that the sound signal is output through a plurality of frequency bands in accordance with the digital signal while changing the number of symbols for each frequency signal based on the number of used frequencies in accordance with setting of the controller  140 . For example, one frequency signal may be output per 1 symbol when two frequencies are used and one frequency signal may be output per 2 symbols when four frequencies are used. 
     The modulator  150  includes frequency oscillators (not shown) for generating as many oscillation frequencies as the number of available frequencies and controls the sound output device  160  to output frequency signals from frequency oscillators that are specified in accordance with the digital signal. 
     The modulator  150  converts the digital signal from the controller  140  into the sound signal using one of frequency shift keying, amplitude shift keying, or phase shift keying while controlling the sound output device  160  to output the sound signal in accordance with the digital signal. 
     Frequency shift keying converts the digital signal into a signal having a frequency corresponding to a data value of the digital signal, amplitude shift keying converts the digital signal by changing the amplitude of the digital signal according to the data value, and phase shift keying converts the digital signal by changing the phase of the digital signal according to the data value. 
     Binary frequency shift keying (BFSK), which is a type of frequency shift keying, converts the digital signal into a signal of a first frequency when the digital signal has a data value of 0 and into a signal of a second frequency when it has a data value of 1. For instance, BFSK converts data value 0 into a signal of a frequency of 2.6 KHz and converts data value 1 into a signal of a frequency of 2.8 KHz. 
     Amplitude shift keying may convert the digital signal into a signal of a frequency of 2.6 KHz with an amplitude of 1 when the digital signal has a data value of 0 and an amplitude of 2 when it has a data value of 1. 
     While the modulator  150  has been described as using frequency shift keying as an example, the modulation scheme used may be changed. Also, the frequency bands used are a mere example and may be changed. 
     If a dead time is set in the digital signal, the modulator  150  discontinues modulation during an interval in which the dead time is set in the digital signal. The modulator  150  modulates the digital signal using pulse width modulation (PWM) and switches an oscillation frequency for modulation off during the interval, in which the dead time is set, to temporarily discontinue the frequency signal modulation during the dead time. This controls inter-symbol reverberation of the sound signal output from the sound output device  160 . 
     The sound output device  160  is activated or deactivated according to a control command from the controller  140 . The sound output device  160  emits a predetermined sound signal including product information by outputting a frequency signal corresponding to the digital signal for a specified time under the control of the modulator  160 . 
     Here, one or more sound output devices  160  may be provided. For example, when two sound output devices are provided, one of the two sound output devices may output a sound signal including product information and the other may output an alarm sound or an effect sound corresponding to state information of the home appliance and may also output an indication sound before a smart diagnosis mode is entered or before the sound signal is output. 
     The sound output device  160  is deactivated after completely outputting the digital signal as the predetermined sound signal in accordance with the output of the modulator  150 . When the selector  130  is manipulated again, the sound output device  160  is reactivated to output the predetermined sound signal carrying product information through the above-described process. 
     While a sound output unit such as a speaker or a buzzer is applicable as the sound output device  160 , a speaker having a wide reproduction frequency range is preferable in order to use a plurality of frequency bands. 
     When the smart diagnosis mode is entered, the sound output device  160  emits a start sound indicating the start of the smart diagnosis mode according to a control command from the main controller  141  and also outputs respective predetermined indication sounds at the start and end of outputting a sound signal carrying product information. 
     In response to a control command from the main controller  141 , the display device  118  displays, on a screen, information such as information received from the selector  130  and the manipulator  117 , operating state information of the home appliance  101 , and information associated with completion of the operation of the home appliance  101 . When the home appliance  101  operates abnormally, the display device  118  also displays fault information about the abnormality on the screen. 
     The display device  118  displays information indicating the smart diagnosis mode when the smart diagnosis mode has been started in response to a control command from the main controller  141 . When the sound output device  160  outputs a sound signal, the display device  118  displays the progress of the sound output in the form of at least one of text, an image, and a numeral. 
     The home appliance  101  may include an output unit such as an illuminating or flickering lamp, a vibrator, or the like, which will not be described herein, in addition to the sound output device  160  and the display device  118 . 
     The home appliance  101  constructed as described above outputs the predetermined sound signal to transmit product information of the home appliance  101  to the service center  200  as described below. 
       FIG. 4  is a block diagram of the diagnostic server of the service center in the home appliance diagnostic system illustrated in  FIG. 1 . 
     When the home appliance  101  emits a sound signal, the sound signal is provided to the portable terminal  80  and then transmitted to the service center  200  over the communication network. The service center  200  receives the sound signal and applies it to the diagnostic server, which then performs a fault diagnoses of the home appliance  101  based on the sound signal. 
     Referring to  FIG. 4 , the diagnostic server of the service center  200  includes a communicator  220 , a signal processor  230 , a data device  240 , a server input device  280 , a server output device  270 , a diagnoser  260 , and a server controller  210  for providing overall control to the diagnostic server. 
     The server input device  280  and the server output device  270  provide a predetermined input/output interface, through which a manager of the service center  200 , a user, and a service technician may check the progress and result of a diagnosis, and receive or output data. 
     The server input device  280  includes input units such as buttons, keys, a touchpad or a switch that the user of the service center  200  manipulates. The server input device  280  includes a connection interface for interfacing with an external input device and a portable memory. 
     When a specific input unit of the server input device  280  is manipulated, the server input device  280  applies a signal to the server controller  210  to allow the diagnostic server to receive a sound signal from the home appliance  101  through the telephone or mobile phone of the user connected to the diagnostic server over the telephone network or mobile network. 
     The server output device  270  includes a display for displaying operation information and diagnosis results of the diagnostic server. 
     The communicator  220  is connected to an internal network of the service center  200  and transmits and receives data to and from the network. The communicator  220  is also connected to an external network such as the Internet to communicate with the external network. Especially upon receipt of a recording command or a reception command through the server input device  280 , the communicator  220  receives a sound signal from the home appliance over the telephone network and transmits a diagnosis result externally when a diagnosis is completed, according to a control command from the server controller  210 . 
     The communicator  220  transmits the diagnosis result to the terminal of the service technician or to the portable terminal of the user. 
     The data device  240  stores control data for controlling the operation of the diagnostic server, a sound signal received from the home appliance such as a laundry treatment machine in the form of sound signal data, reference data for sound signal conversion and product information extraction, and fault diagnostic data for diagnosing whether the home appliance is out of order and the cause of a fault. 
     Also, the data device  240  stores temporary data generated during the process of converting received data or detecting product information and also stores diagnosis result data and a diagnosis result report to be transmitted to the user. 
     The data device  240  receives, outputs, manages, and updates data under the control of the server controller  210 . 
     The signal processor  230  converts the received sound signal into a readable sound signal, extracts product information from the converted sound signal, and applies the product information to the diagnoser  260 . 
     The signal processor  230  converts and stores the received analog sound signal. The signal conversion is the reverse of signal conversion in the home appliance  101 . Preferably, each home appliance and the diagnostic server convert data using the same scheme preset by agreement therebetween. The signal processor  230  converts an analog sound signal in a predetermined frequency band into a digital signal through demodulation using one of frequency shift keying, amplitude shift keying or phase shift keying. 
     After extracting the digital signal on a frame basis from the demodulated data, the signal processor  230  acquires the product information by decoding the digital signal. The signal processor  230  detects a preamble, acquires the digital signal including the product information based on the preamble, and extracts the product information of the home appliance from the digital signal by decoding the digital signal of a predetermined format using a decoding scheme corresponding to the coding scheme used for the product information in the home appliance. 
     The signal processor  230  converts and analyzes the digital signal based on structure or format information, frequency characteristics, and decoding information of the digital signal stored in the data device  240 . 
     The product information is applied to the diagnoser  260  and stored in the data device  240 . 
     The diagnoser  260  determines the operating state of the home appliance  101  and whether the home appliance  101  is out of order by analyzing the input product information according to a control command from the server controller  210 . The diagnoser  260  has a diagnosis program for analyzing the product information of the home appliance and determining the state of the home appliance based on the product information, and diagnoses the home appliance  101  using the fault diagnostic data stored in the data device  240 . 
     Also, the diagnoser  260  analyses the cause of the fault, derives a solution or a measure to take against the fault, and outputs a diagnosis result in relation to a customer service direction. 
     The diagnoser  260  classifies data of the product information according to a predetermined criterion and performs the fault diagnosis according to a combination of associated data among the classified data. During the fault diagnosis, the diagnoser  260  determines which item is correctly diagnosable and which item is not correctly diagnosable and performs fault diagnosis on diagnosable items in descending order of fault probability. 
     The diagnosis result includes a fault ID or location, a probability-based fault cause list, a defective part list, and guidance information indicating whether a service technician is to be dispatched. 
     The server controller  210  controls data transmission and reception through the communicator  220  and data input and output through the server input device  280  and the server output device  270 . In addition, the server controller  210  controls the operations of the signal processor  230  and the diagnoser  260  to diagnose the fault of the home appliance  101 . The server controller  210  performs a control operation such that the diagnosis result of the diagnoser  260  is output through the server output device  270  and transmitted through the communicator  220 . 
     The server controller  210  performs a control operation such that the diagnosis result of the diagnoser  260  is output through the server output device  270 . Hence, the service center  200  notifies the user of an action to be taken in relation to the malfunction of the home appliance  101  by voice over the telephone network or dispatches a service technician to the user. In the latter case, the server controller  210  transmits the diagnosis result to the terminal of the service technician through the communicator  220 . 
     Also, the server controller  210  may transmit the diagnosis result to the user through the communicator  220 . 
     In the mean time, when an error has occurred during the signal processing or the diagnosis process, the server controller  210  outputs an alarm sound or a message requesting sound signal retransmission of the home appliance  101  through the server output device  270 . In this case, the service center  200  requests the user connected thereto through the communication network to re-output a sound signal of the home appliance. 
     The product information of the home appliance, which is transmitted after being converted into a sound signal for fault diagnosis, includes a plurality of data associated with the operations of the home appliance. The home appliance stores a plurality of diagnostic data required for fault diagnosis. The following describes the product information. 
     As described above, the home appliance stores product information in the memory  145  and the product information includes a plurality of diagnostic data. 
     The main controller  141  stores diagnostic data corresponding to the operating state of the home appliance in the memory  145  or stores the diagnostic data in the memory  145  after temporarily storing it in the storage device  146 . Here, the main controller  141  changes the time or frequency of storage of the diagnostic data according to the type of the diagnostic data. 
     The main controller  141  reads the diagnostic data stored in this manner when the smart diagnosis mode is entered, encodes the read diagnostic data into a digital signal in a predetermined format through the encoder  142 , converts the digital signal into a sound signal through the modulator  150 , and outputs the sound signal through the sound output device  160 . 
     The main controller  141  performs data initialization before starting operation and stores diagnostic data at intervals of a specific period or as needed while the main controller  141  operates according to setting. Here, the main controller  141  maintains initial values of an operation that has not been actually performed although it has been set to be activated. 
     Depending on the type of the diagnostic data, the main controller  141  stores diagnostic data immediately each time the data value of the diagnostic data has changed, stores diagnostic data when an error has occurred, or stores diagnostic data associated with each operation such as washing, rinsing, or spin-drying upon completion of the operation. 
     Thus, the memory  145  stores product information including the operation information, the usage information and the fault information under control of the main controller  141 . The storage device  146  also stores temporary data about the operation information and fault information generated during the operation of the home appliance. For example, the product information may include the number of uses of the laundry treatment machine, a set course, option setting information, an error code, a value measured by a sensor, data calculated by the controller  140 , and operation information of each component. 
     In the case of the laundry treatment machine, the operation information includes information necessary for the operation of the laundry treatment machine, such as information about the washing mode of the laundry treatment machine, information about the spin-drying mode of the laundry treatment machine and information about the rinsing mode of the laundry treatment machine. 
     The fault information may include, when the laundry treatment machine performs each operation, various information including fault information generated during each operation, device fault information of the laundry treatment machine, error codes corresponding to fault information, information of the controller  140 , values sensed by the sensing device  170 , sensed values of the motor, fault information of the wash water supply, and fault information of the drainage device. 
     The usage information may include various information including the number of uses of the laundry treatment machine by the user, a course set by the user, and option setting information set in the laundry treatment machine. That is, the usage information may include contents input to the laundry treatment machine by the user or information initially set in the laundry treatment machine. 
     The product information is stored as in the following table. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Category 
                 Name 
                 Size (byte) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Operation info 
                 Status 
                 1 
               
               
                   
                 Customer info 
                 Common 
                 11 
               
               
                   
                   
                 Wash 
                 4 
               
               
                   
                   
                 Rinse 
                 4 
               
               
                   
                   
                 Spin 
                 6 
               
               
                   
                   
                 Dry 
                 8 
               
               
                   
                   
                 Error code 
                 1 
               
               
                   
                   
                 Counts 
                 8 
               
               
                   
                   
                 Options 
                 9 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 1, “Category” indicates the attributes of the product information and “Name” provides the meaning of each category. 
     “Status” indicates information of a mode which is performed last among all modes of the laundry treatment machine  101 . That is, “Status” indicates product information of the laundry treatment machine  101  about the rinsing mode when the laundry treatment machine  101  performs the rinsing mode last among the washing, spin-drying, and rinsing modes at the request of the user. “Status” is 1 byte long. 
     “Common” is product information having an attribute that should be sampled over all modes of the laundry treatment machine  101 . That is, “Common” indicates product information in each mode or at a specific time when the motor, the wash water supply, and the like operate throughout all modes of the laundry treatment machine  101 . “Common” is set to be 11 bytes long. Here, data having a “Common” attribute is initialized at a preparatory step before the operation starts and is stored as needed during the operation and is also stored when a failure has occurred or when the operation is terminated. Depending on the type of the “Common” data, the “Common” data may be stored only when a specific error has occurred. 
     “Wash” indicates product information having an attribute that should be sampled in the washing mode. For example, “Wash” provides product information having an attribute that should be sampled in the washing mode such as the level of wash water or the operation time of the wash water supply when the washing mode is performed. “Wash” is set to be 4 bytes long. Data about “Wash” is stored when the washing mode is being performed or when the washing mode has been completed and is also stored when an error has occurred. Here, when spinning, which is the last operation of the washing mode, has been completed, it is determined that the washing mode has been completed, and diagnostic data about “Wash” is stored before rinsing starts, i.e., before water supply starts in the rinsing mode. 
     “Rinse” indicates product information having an attribute that should be sampled in the rinsing mode. “Rinse” is 4 bytes long. “Spin” indicates product information having an attribute that should be sampled in the spin-drying mode. Data about rinsing is stored while the rinsing mode is performed, when the rinsing mode is completed, or when an error has occurred. Rinsing data is stored during each rinsing operation and diagnostic data about rinsing is finally stored before the spin-drying mode starts after spinning is performed in the last rinsing operation. 
     Here, “Spin” is set to be 6 bytes long. “Dry” indicates product information having an attribute that should be sampled in the drying mode. “Dry” is set to be 8 bytes long. Diagnostic data about spin-drying is stored when the spin-drying mode has been completed or when an error has occurred. 
     In the washing, rinsing, and spin-drying mode, diagnostic data about bubble detection is stored immediately upon bubble detection. 
     “Error code” indicates a code of an error, of which the user is alerted upon detection of an abnormality in the laundry treatment machine  101  while in operation. That is, “Error code” indicates a typical operation error of the laundry treatment machine  101 , of which the user is alerted when an abnormality has occurred in the laundry treatment machine  101 . “Error code” is set to be 1 byte long. 
     For example, “Error code” indicates an error message displayed on a display (not shown) or a beep emitted through a buzzer when the laundry treatment machine  101  has malfunctioned or a usage error has occurred. Among product information, such an error code is set to inform the user of the location of an error in the laundry treatment machine  101  which has malfunctioned. The error code may not only be displayed on the display device but may also be output as an alarm sound. 
     For example, when an error code included in product information has a data value of 0, the error code indicates that the laundry treatment machine  101  is functioning normally or indicates that a malfunction, which is not classified as an error code, has occurred in the laundry treatment machine  101 . An error code having a data value of “1” may indicate a door malfunction, “2” a water supply malfunction, “3” a drainage malfunction, “4” a balance malfunction, “5” an FE malfunction, “6” a switch sensor (PE) malfunction, “7” a water supply (IE) malfunction, “8” a motor (LE) malfunction, “9” a CE malfunction, and “10” a drying malfunction. Error codes having other data values may indicate other specific malfunctions. 
     Such an error code is used to extract associated data according to the value of the error code when the diagnostic server has diagnosed the laundry treatment machine  101  with a fault, to compare the extracted data with corresponding reference data or diagnostic data to analyze the cause of the fault, and to derive a measure to take against the fault. The diagnostic server determines an operation of the laundry treatment machine  101  during which the fault has occurred based on state information included in the product information. 
     “Counts” indicates product information specifying the number of uses of the laundry treatment machine  101  by the user, the number of error occurrences, etc. “Counts” is set to be 8 bytes long. When the laundry treatment machine  101  has started operation, “Counts” is not initialized, maintaining its previous value, at a preparatory step. 
     “Options” indicates product information including options that the user has set when operating the laundry treatment machine  101 . That is, the user sets “Options” for the laundry treatment machine  101 , for example, a washing time to 15 minutes, a spin-drying time to 5 minutes, and a rinsing time to 10 minutes as “Options”. “Options” is set to be 9 bytes long. “Options” are stored when an error code has occurred or when the washing mode has been completed. 
     The sizes, categories, and names of product information are merely an example and thus may be changed depending on the characteristics of the home appliance. 
     The main controller  141  causes the home appliance to operate according to setting values such as options or an operation course set through the manipulator  117  of the input device  125 . For example, when the home appliance is a laundry treatment machine, the main controller  141  classifies its operation steps into preliminary, washing, rinsing, spin-drying, drying, and termination steps and further classifies each step into operations and stores information indicating an operation that the home appliance has performed last as state information. 
     Thus, the state information includes information about the operation that the home appliance has performed last among all operations of the home appliance. For example, the state information includes information about an operation step that the home appliance performs last among preliminary, washing, rinsing, spin-drying, drying, and termination steps into which operation steps of the laundry treatment machine are divided before the laundry treatment machine performs specified operations. Here, each step may be classified into sub-steps. For example, the washing step may be further classified into rough washing, soaked washing, main washing, and finishing washing steps and the rinsing step may be further classified into first-time rinsing, second-time rinsing, third-time rinsing, and fourth-time rinsing steps. The first-time rinsing step may also be further classified into a drainage step, a brief spinning step, a main spinning step, and a water supply step. The state information includes information about such finely classified operations of the home appliance. 
     When an abnormality has occurred during the rinsing mode of the laundry treatment machine, a value indicating the rinsing mode is stored in the state information since the rinsing mode has been performed last. Here, each mode may be further classified and thus the state information may indicate in which rinsing step the abnormality has occurred in the rinsing mode, whether the abnormality has occurred during the spinning step in the rinsing mode, whether the abnormality has occurred during water supply, and whether the abnormality has occurred during drainage. 
     Here, the state information may be about 1 byte long and may include information about each of about 60 to 64 operations into which the steps of the home appliance are divided. 
     Here, the values “0” to “5”, state information may indicate operations of a preliminary step, specifically, the value “0” may indicate an initialization step, “2” a stop step, “3” a course scheduling step, “4” a freezing detection step, and “5” a laundry quantity detection step. The values “55” and “56” may indicate drying steps, specifically, the value “55” may indicate a hot air drying step and “56” a cool-down step. 
     The values “6” to “9” may indicate the rough washing mode, “10” and “11” the soak mode, “12” to 20” the wash mode, “21” to “48” the rinsing mode”, “49” to “52” the spin-drying mode, “55” and “56” the drying mode, and “57” to “59” the termination mode. When the data value of the state information is “0”, this indicates that power is off and, when the data value is “12”, this indicates that initial water supply has been performed last in the washing mode. When the value of the state information is “28”, this indicates that brief spinning has been performed last in the second-time rinsing step. 
     This state information is updated as needed during operation of the home appliance. That is, while the washing mode is being performed, corresponding state information is stored and, when the rinsing mode is performed after the washing mode is completed, a corresponding value is stored as state information. 
     The diagnostic server can determine which operation has been performed last in the home appliance through the state information included in the product information and perform fault diagnosis using associated diagnostic data. 
     Common data described above is stored in the storage device  146  immediately each time data is created or each time the value of data has changed. Common data is temporarily stored in the storage device  146  and is then stored in the memory  145  when the home appliance has stopped operation since all operations are completed or since an error has occurred. 
     “Current Limit Counter” indicates the total number of current limit operations until the home appliance terminates operation after starting operation. The current limit counter is incremented by 1 each on-off cycle of the motor. 
     When the motor controller generates and applies a signal for controlling the motor to the motor, an excessive current exceeding an allowable level may be generated, damaging the motor controller and the motor. Thus, the motor controller performs a “current limit” operation to forcibly cut off a motor current when the level of the current has reached a limit level which is preset to prevent damage to the motor controller and the motor due to overcurrent. 
     “FO Counter,” which is an overcurrent control counter, indicates the total number of times overcurrent is cut off by hardware until the home appliance terminates operation after starting operation. The FO limit counter indicates the number of times overcurrent is limited by hardware and is maintained at “0” when the motor controller performs normal control. Thus, when the value of the FO counter is zero, this indicates that the motor controller is functioning normally and, when the value of the FO counter is nonzero, this indicates that an error has occurred in the motor controller, i.e., that the motor controller is out of order. 
     “Bubble_Counter” indicates the total number of times bubble detection is performed until the home appliance terminates operation after starting operation. 
     “RPM Detect” indicates a rotation speed value of the motor that a hall sensor provided for the motor has measured during operation of the motor. The RPM Detect data enables determination of abnormality in the motor or hall sensor. For example, when the current limit counter is nonzero while the “RPM Detect” value is zero indicating that no rotation speed has been measured, it can be determined that the hall sensor has failed to measure the rotation speed since the hall sensor is out of order although the motor has been activated. 
     Here, an “RPM Detect” value of “0” indicates that the hall sensor and the motor are normal, “1” indicates that the RPM is 0, and “2” indicates that the RPM is kept at 0 for the last two seconds or that the RPM was nonzero at least once for the remaining time. 
     The “RPM Detect” value is stored each time it is detected and thus an “RPM Detect” value stored last is maintained as a final motor speed measurement. 
     “Power off info” includes information as to whether the home appliance has terminated operation when power is turned off after completing all set operations or without performing part of the set operations. For example, the value of “Power off info” may be 1 when power is turned off due to power failure. 
     “Water Level End” includes water level measurement of the tub when the home appliance has terminated operation. 
     “Error Water Drainage Time” indicates the time required for drainage (drainage time) and, specifically, a drainage time that was stored last is stored in this information upon occurrence of an error. The “Error Water Drainage Time” value is changed when drainage is performed and the larger of a previously stored value and a newly measured value is stored as the “Error Water Drainage Time” value. Thus, the maximum time required for drainage is stored as the error water drainage time information. That is, the longest of the drainage times measured when drainage was performed a number of times is stored as the “Error Water Drainage Time” value. 
     Namely, the “Error Water Drainage Time” value indicates the longest of all operation times required for drainage which are measured during drainage operations and thus a measured drainage time value is stored when it is greater than a previously stored value such that the maximum drainage time is stored as the “Error Water Drainage Time” value. 
     “IPM Max Temperature” indicates a measured temperature of the motor controller that applies a control signal to the motor. While the motor controller generates and applies a motor control signal to the motor, the motor controller generates heat since it performs a large amount of calculation. The temperature of the motor controller is measured and recorded since the motor controller may be damaged when the temperature has exceeded a certain level. 
     “Error Temperature” includes information about a temperature sensor, which has measured an abnormal temperature or a temperature error, among a plurality of temperature sensors provided in the home appliance. For example, an error temperature value of “0” indicates that there is no abnormality, “1” indicates a temperature sensor provided on the tub, “2” indicates a temperature sensor provided on an AF, and “3” indicates a temperature sensor provided on a duct. Here, the order or types of temperature sensors corresponding to the error temperature values may be changed according to setting. 
     That is, the error temperature value “1” indicates that an abnormal temperature is measured at the temperature sensor provided on the tub. 
     Here, each temperature sensor provided on the home appliance applies data corresponding to a measured temperature to the main controller. The value input to the main controller is not the measured temperature level but instead is a corresponding one of 255 levels into which resistance, current, or voltage values corresponding to temperature are classified. 
     When a value measured by a temperature sensor is 0 or 255, the main controller may determine that the temperature sensor is out of order since the values 0 and 255 cannot be measured when the temperature sensor operates normally and are measured due to a wiring or connection problem. The value 0 or 255 may also be applied to the main controller when temperature exceeds a range of temperature levels that can be measured by the temperature sensor. In the case of the laundry treatment machine, such abnormal data is applied to the main controller when temperature of a dryer heater exceeds the measureable range of a temperature sensor provided on the dryer heater due to overheating caused by failure of the fan. Thus, the main controller stores information of the temperature sensor as the error temperature information. 
     “Error Bubble Flag” indicates whether bubbles have been detected upon error occurrence and is set when bubbles have been detected and is cleared when bubbles have been removed. 
     “Error Voltage” indicates a voltage value measured upon error occurrence. A generally measured voltage value is not stored as the “Error Voltage” value. Instead, the measured voltage value is converted into one of a plurality of levels into which measured voltage values are classified and the converted level is stored as the “Error Voltage” value. 
     “Fan motor RPM” indicates a rotation speed of the fan motor when an error code has occurred. The rotation speed of the fan motor is measured, before the fan motor is deactivated, and the fan motor is deactivated after the measured rotation speed is stored as the “Fan motor RPM” value. 
     Specifically, when the cool-down step is entered, the rotation speed of the drying fan in the laundry treatment machine is measured and stored as the “Fan motor RPM”. 
     “ReWater Flag” is set during water resupply and is cleared when water resupply is completed. The “ReWater Flag” value is stored when an error has occurred or when the operation is terminated. The “ReWater Flag” value is set depending only on whether water resupply is being performed, regardless of whether water resupply is performed in the washing step or in the rinsing step. 
     “Door Bimetal Flag” stores an on/off state of a bimetal on the door when a door-related error has occurred. 
     Data used in the overall operation of the laundry treatment machine as described above is temporarily stored and updated as needed and is stored in the memory when an error has occurred or when the operation is terminated. 
     The diagnostic data includes data items corresponding to operations which are stored according to operating states. 
     In the operation steps of the washing mode, a wash water supply time, a wash water temperature, a wash bubble flag, a wash low-voltage flag, a wash valve switching flag, and a heater forcible cut-off flag are stored as diagnostic data of the washing mode. These data items are temporarily stored and updated during the washing mode and are stored in the memory when washing is completed. 
     Here, the wash water supply time data “Water supply time_W” is the time required for water supply in the initial water supply step, i.e., the time required until water supply is completed after water supply starts. The stored wash water temperature data includes a first wash water temperature “Water Temperature W 0 ” and a second wash water temperature “Water Temperature W 1 ”. Here, a temperature of the tub when the operation starts is stored as the first wash water temperature and a temperature of the tub immediately after the initial water supply is completed is stored as the second wash water temperature. That is, the first wash water temperature “Water Temperature W 0 ” is a temperature of the tub that is measured when the operation starts, i.e., when water supply starts. The first wash water temperature is not measured when water supply is resumed after being stopped. On the other hand, the second wash water temperature “Water Temperature W 1 ” is a temperature of the tub that is measured immediately after the initial water supply is completed. The temperature of the tub can be considered the temperature of the wash water since the temperature of the tub varies with the temperature of the wash water when water supply is performed. Whether the state of water supply, the sensor, or the like are out of order is determined by comparing the two wash water temperatures. 
     The wash bubble flag indicates whether or not bubbles have occurred during washing and spinning in the washing mode and may be set to “1” when bubbles have occurred and set to “0” when no bubbles have occurred. The wash low-voltage flag is set when a low voltage has been input. The wash valve switching flag is a flag associated with erroneous connection of cold and hot water valves. The heater forcible cut-off flag is set to a value indicating whether the heater has been forcibly cut off based on the heating time. Specifically, the heater forcible cut-off is stored as a history of forcible cut-off of the heater due to an excessive heating time and forcible cut-off of the heater due to no temperature change. When the heater has been cut off at least once, the heater forcible cut-off flag is set to “1”, indicating that forcible heater cut-off has occurred. 
     Diagnostic data of the rinsing mode includes a rinse water supply time, a rinse water temperature, a rinse bubble flag, a rinse low-voltage flag, and main rinse valve information and are temporarily stored and updated while the rinsing mode is being performed or when the rinsing mode is completed and are finally stored in the memory when the rinsing mode is completed. 
     The time required for water supply for rinsing is stored as the rinse water supply time as in the washing mode. When rinsing is performed a plurality of times, the maximum of a plurality of measured rinse water supply times is stored as the rinse water supply time. The rinse water temperature data includes a first rinse water temperature and a second rinse water temperature, which are tub temperatures measured respectively before and after water supply, as in the washing mode. The temperature difference between before and after water supply can be determined using the first and second rinse water temperatures. 
     The rinse bubble flag is set or cleared according to whether bubbles have occurred during rinsing. The rinsing low-voltage flag is set when a low voltage is generated during rinsing or spinning in the rinsing mode. The main rinse valve information includes information indicating whether the main valve used for final rinsing is a cold water valve or a hot water valve. 
     Diagnostic data of the spin-drying mode includes a spin-dry entry trial count “UB try counter”, a wet load level, an offset value, a target rotation speed, a maximum rotation speed, a spin-dry bubble flag, and a spin-dry low-voltage flag and are stored while the spin-drying mode is being performed or when the spin-drying mode is completed. 
     First, the “UB try counter” value is described as follows. The tub or drum may bump against the casing of the laundry treatment machine when spin-drying is performed depending on how much the tub is tilted due to laundry. Large eccentricity of laundry may cause loud noise and makes high-speed spin-drying impossible and may also damage the laundry treatment machine. Accordingly, the degree of balance or unbalance (or eccentricity) is measured before spin-drying is performed. When the degree of unbalance or eccentricity is great, the laundry treatment machine does not directly start spin-drying and performs an operation for untangling and uniformly redistributing laundry. That is, the “UB try counter” data indicates the number of times the laundry treatment machine has reattempted entry to the spin-drying step since it cannot perform the spin-drying operation due to large eccentricity. This is proportional to the number of times the laundry treatment machine has performed eccentricity measurement and laundry untangling. 
     The “Wet load level” data indicates the quantity of laundry measured last before high-speed spin-drying is performed. Since the laundry quantity measured when washing starts is the quantity of dry laundry, the quantity of wet laundry before spin-drying is performed is recalculated and stored as the “wet load level” data. 
     The quantity of laundry may be classified into a plurality of levels such as very small, small, middle, normal, large, very large, and single load levels. The “offset value” is a value for setting a target rotation speed during spin-drying and the target rotation speed is reset based on the eccentricity (or the degree of unbalance), regardless of an initially input operation setting. The maximum rotation speed is a value measured when final spin-drying is performed. 
     The spin-dry bubble flag is associated with whether bubbles have occurred during spin-drying and the spin-dry low-voltage flag indicates whether a low voltage is generated during spin-drying. 
     Diagnostic data of the drying mode includes a lowest water level, a dryer heater operation count, a lowest dry temperature, a motor rotation speed, a lowest voltage, a dry time, a maximum fan motor rotation speed (RPM) flag, and a dry low-voltage flag and are stored while the drying mode is being performed or when the drying mode is completed. 
     The lowest water level is the lowest of water levels measured until the drying mode is completed from when initial drainage is completed after the drying mode is entered. The dryer heater operation count is the number of on and off operations of the dryer heater and the lowest dry temperature is the lowest of duct temperature values measured immediately until the cool-down step is entered. 
     The fan motor rotation speed “fan motor RPM” is a measured rotation speed value of the dry fan of the laundry treatment machine when the cool-down step is entered. The lowest dry voltage is the lowest of voltage values measured during the drying mode after the drying mode is entered. The dry time is a time measured after preliminary drying in the spin-drying mode. The maximum fan motor rotation speed flag is set when the rotation speed measured during operation of the fan motor has exceeded a predetermined speed and the dry low-voltage flag is set when a low voltage is provided in the drying mode. 
     The diagnoser  260  diagnoses a fault using such data included in the product information and derives a solution to the fault. 
     Not only data according to operations of the home appliance but also both an error occurrence count in the home appliance and setting data input through the manipulator  117  are included as diagnostic data in the product information. 
     The error occurrence count includes the number of occurrences of errors of each error code, the number of operations of the home appliance, the number of tub washing operations of the laundry treatment machine, or the like. The setting data includes setting values associated with a wash course, a rinsing operation count, a language for use, use of steam, sound volume control, spin-drying strength, and wash water temperature. 
     The main controller  141  stores such diagnostic data as product information in the memory. When the home appliance enters the smart diagnosis mode in response to input by the user, the main controller  141  reads the stored diagnostic data and creates product information and the encoder  142  encodes the product information to generate a digital signal in a predetermined format. The generated digital signal is applied to the modulator, which converts the digital signal into a combination of predetermined frequency signals. The sound output device  160  outputs the combination of predetermined frequency signals as a predetermined sound signal. 
       FIG. 5  is a flow chart illustrating a diagnostic method for a home appliance diagnostic system according to the present invention. 
     As shown in  FIG. 5 , when the home appliance  101  outputs product information as a predetermined sound signal, the sound signal is transmitted to the service center  200  over a communication network through which the user is connected to the service center  200 . 
     The diagnostic server of the service center  200  receives the sound signal output from the home appliance  101  ( 310 ) and converts the sound signal according to a predetermined scheme to extract the product information (S 320 ). The diagnostic server then diagnoses the state, fault, and fault cause of the home appliance using a plurality of data included in the product information and starts fault diagnosis to determine a measure to take against the fault (S 330 ). 
     The diagnoser  260  then obtains version information of the home appliance diagnostic system and model information of the home appliance through the plurality of data included in the product information and analyzes diagnostic data included in the product information to perform fault diagnosis. 
     The diagnoser  260  first analyzes state information or an error code included in the diagnostic data included in the product information and compares data associated with the state information or error code with fault diagnostic data or reference data to perform fault diagnosis. Basically, the diagnoser  260  can use all diagnostic data included in the product information. However, the diagnoser  260  can use state information or an error code included in the diagnostic data to analyze data associated with the state information or error code, thereby checking the state of the home appliance and performing fault diagnosis more quickly. Here, the diagnoser  260  classifies diagnostic data included in the product information according to a predetermined criterion, i.e., according to the state information or error code, to find and diagnose a fault that is the most likely cause of abnormality of the home appliance. 
     The diagnoser  260  checks whether an error code has been set in the plurality of diagnostic data included in the product information (S 340 ). When the error code is zero or an unregistered error code has been generated, the diagnoser  260  determines that no error code has been generated and performs fault diagnosis on the home appliance using diagnostic data or state information, other than the error code, included in the product information (S 350 ). 
     When an error code has been set, the diagnoser  260  determines that the error code has been generated in the home appliance, identifies a portion of the home appliance, in which abnormality has occurred, using the error code, extracts diagnostic data associated with the identified portion, and performs fault diagnosis using the extracted diagnostic data (S 360 ). 
     The diagnoser  260  diagnoses the cause of the fault and derives a measure for or a solution to the fault cause (S 370 ). The diagnoser  260  stores the fault cause and the solution derived through such fault diagnosis as a diagnosis result (S 380 ). 
     Since the home appliance may have a plurality of faults, the diagnoser  260  performs additional diagnosis using other associated diagnostic data corresponding to the type of the error code (S 390 , S 360 , and S 380 ). 
     When diagnosis is completed, the diagnoser  260  applies the diagnosis result to the server controller  210 . 
     The server controller  210  generates a final diagnosis result through the diagnosis result received from the diagnoser  260  (S 400 ). That is, when the home appliance has a plurality of faults, there may be a number of causes of and solutions to the faults, and therefore the server controller  210  combines at least one diagnosis result received from the diagnoser  260  to generate a final diagnosis result. 
     The server controller  210  first outputs a result of diagnosis of the state or fault of the home appliance and the fault cause through the server output device  270  (S 410 ). Here, when a plurality of fault causes exist, the server controller  210  may display the fault causes in a list. When one of the displayed fault causes is selected and input, the server controller  210  outputs a solution to the fault cause (S 420 ). 
     The server controller  210  may transmit the diagnosis result via an email or message using a registered email address or telephone number of the user (S 440 ). 
     Here, a counselor of the service center  200  may check the diagnosis result displayed on a screen on the server output device  270 . The counselor of the service center  200  may provide voice guidance on the displayed cause and solution to the user connected through a telephone. The counselor of the service center  200  may also perform a procedure for scheduling an appointment for a service technician to visit the user&#39;s home according to the cause and solution. 
     When the solution includes dispatching of a service technician, the server controller  210  may transmit the diagnosis result to the terminal of the service technician (S 440 , S 450 ). 
       FIG. 6  is a flow chart illustrating a diagnostic method using product information in a home appliance diagnostic system of the present invention. 
     The diagnoser  260  prepares reference data or fault diagnostic data according to smart diagnosis version and model information and first checks an error code among diagnostic data included in product information to perform fault diagnosis. 
     Among a plurality of error codes, a drainage error (i.e., a drainage error code) is an error which occurs in association with drainage of water to the outside from the drum or the tub in the laundry treatment machine. 
     For example, an error associated with drainage may occur since some bubbles still remain after drainage is completed when a lot of bubbles were generated due to introduction of a large amount of detergent. A drainage error may also occur when a low voltage is applied to the laundry treatment machine and when a drainage pump operates abnormally. Drainage is performed by driving the drainage pump until a target water level is reached. A drainage error may also occur when the target water level is not reached within a predetermined time. 
     When a drainage error has been set as an error code, the diagnoser  260  extracts data associated with drainage from diagnostic data to perform fault diagnosis. The diagnoser  260  performs fault diagnosis using at least one of an error bubble flag, a drainage time, a bubble counter, an error voltage, and a water temperature to analyze a cause of the drainage error and derive a measure for or a solution to the drainage fault. 
     “Error Bubble Flag” indicates whether bubbles have been detected upon error occurrence and is set when bubbles have been detected and is cleared when bubbles have been removed. “Error Water Drainage Time” indicates the longest of all operation times required for drainage which are measured during drainage operations. That is, the longest time required to perform drainage is stored as “Error Water Drainage Time”. Here, a measured drainage time value is stored when it is greater than a previously stored value such that the maximum drainage time is stored as the “Error Water Drainage Time” value. “Bubble_Counter” indicates the total number of times bubble detection is performed until the home appliance terminates operation after starting operation. “Error Voltage” indicates a voltage value measured upon error occurrence. A generally measured voltage value is not stored as the “Error Voltage” value. Instead, the measured voltage value is converted into one of a plurality of levels into which measured voltage values are classified and the converted level is stored as the “Error Voltage” value. 
     A temperature of the tub, which is measured when the operation starts, i.e., when water supply starts, is stored as a first wash water temperature “Water Temperature W 0 ”. The first wash water temperature is not measured when water supply is resumed after being stopped. On the other hand, a temperature of the tub, which is measured immediately after the initial water supply is completed, is stored as a second wash water temperature “Water Temperature W 1 ”. The temperature of the tub can be considered the temperature of the wash water since the temperature of the tub varies with the temperature of the wash water when water supply is performed. 
     Since these data items are associated with the drainage error, the diagnostic server of the service center  200  performs fault diagnosis on the drainage error using such data items acquired from the product information. 
     When the error code is a drainage error code (S 480 ), the diagnoser  260  performs fault diagnosis using diagnostic data associated with drainage operations among a plurality of diagnostic data included in the product information. When the error code is not a drainage error code, the diagnoser  260  checks other error codes using other diagnostic data (S 490 ). 
     The diagnoser  260  determines whether an error bubble flag has been set among the common data of the plurality of diagnostic data (S 500 ) and checks the value of the bubble counter among the common data when the error bubble flag has been set (S 510 ). 
     When the bubble count is equal to or greater than a reference count, the diagnoser  260  determines that the cause of the fault is an error due to generation of excessive detergent bubbles (S 520 ). That is, the diagnoser  260  determines that the error corresponding to the error code is caused by excessive bubble generation due to excessive detergent introduction when the error code is the drainage error code, the error bubble flag has been set, and the bubble count is equal to or greater than the reference count. For example, the diagnoser  260  may determine that excessive bubbles have been generated when bubbles have been detected 3 or 5 times. 
     Here, since such an error is caused by failure to completely remove bubbles, the diagnoser  260  derives, as a solution to the fault cause, a solution of advising the user to again perform a drainage operation after bubbles disappear and then to use an appropriate amount of detergent (S 530 ). 
     The diagnoser  260  stores this diagnosis result (S 570 ). 
     When the bubble count is less than the reference count, the diagnoser  260  determines that the fault cause is an error due to program malfunction (S 540 ) and derives a solution of dispatching a service technician to fix the program malfunction (S 550 ). 
     The diagnoser  260  stores this diagnosis result (S 570 ). 
     The diagnoser  260  determines that bubbles are absent when no error bubble flag has been set although the error code is a drainage error code. The diagnoser  260  stores this diagnosis result and performs addition fault diagnosis using other diagnostic data. 
       FIG. 7  is a flow chart illustrating another diagnostic method using product information in a home appliance diagnostic system of the present invention. 
     Upon determining that the error code is a drainage error code (S 600 ) after performing diagnosis as described above, the diagnoser  260  performs fault diagnosis using corresponding diagnostic data. The diagnoser  260  checks other error codes when the error code is not a drainage error code (S 610 ). 
     The diagnoser  260  determines whether the error water drainage time is equal to or longer than a reference time (S 620 ). Since the amount of supplied water varies depending on the amount of wash water, the drainage time may also vary depending on the amount of wash water. Thus, the reference drainage time may be set according to the amount of water that is set according to the amount of laundry. 
     When the error water drainage time is equal to or longer than the reference time, the diagnoser  260  determines whether the error voltage is lower than a reference voltage (S 630 ). Here, the reference voltage is set to a voltage which fails to activate the home appliance when it is supplied to the home appliance. 
     When the error water drainage time is equal to or longer than the reference time and the error voltage is lower than the reference voltage, the diagnoser  260  determines that the fault cause is an error due to drainage malfunction (S 640 ) and derives a solution of requesting that the user check the low supplied voltage, check whether the drainage filter is clogged, and clean the drainage filter (S 650 ). 
     When the error water drainage time is equal to or longer than the reference time and the error voltage is equal to or higher than the reference voltage, the diagnoser  260  determines that the fault cause is an error due to clogging of the drainage filter (S 660 ) and derives a solution of requesting that the user check whether the hose is bent, check whether the drainage filter is clogged, and clean the drainage filter (S 670 ). 
     The diagnoser  260  accumulates and stores the diagnostic results (S 680 ). 
     When the error water drainage time is equal to or longer than the reference time, the diagnoser  260  also determines whether the first water temperature is less than a reference water temperature (S 690 ). That is, when a value measured through the temperature of the tub before water supply is less than the reference water temperature, the diagnoser  260  determines that the fault cause is an error due to drainage malfunction (S 700 ) and derives a solution of requesting that the user check whether the drainage pump has frozen and allow, when the drainage pump has frozen, the home appliance to reattempt to perform the drainage operation after it has unfrozen, and also check whether the hose is bent (S 710 ). Preferably, the reference water temperature is set to a temperature that is expected to freeze the water pipe with reference to the general supply water temperature. 
     When the error water drainage time is equal to or longer than the reference time and the value measured through the temperature of the tub before water supply is higher than the reference water temperature, the diagnoser  260  determines that the fault cause is an error duce to clogging of the drainage filter and derives a solution of requesting that the user check whether the hose is bent and check whether the drainage filter is clogged and clean the drainage filter (S 730 ). 
     On the other hand, when the error water drainage time is less than the reference time, the diagnoser  260  determines that the fault cause is an error due to program malfunction since an error has occurred although drainage is functioning normally (S 740 ) and derives a solution of dispatching a service technician to inspect the program (S 750 ). 
     The diagnoser  260  stores the respective diagnosis results (S 750 ). 
     Since the error may occur due to a plurality of causes as in  FIG. 5 , the diagnoser  260  performs fault diagnosis using a plurality of diagnostic data associated with the error code. 
     The server controller  210  combines the diagnosis results of the diagnoser  260  to generate a final diagnosis result and outputs the final diagnosis result as described below. 
       FIG. 8  illustrates exemplary fault diagnosis results using product information in a home appliance diagnostic system of the present invention. 
     As shown in  FIG. 8 , the server controller  210  combines the diagnostic results that the diagnoser  260  generates using a plurality of diagnostic data and outputs the combined diagnosis result as a final diagnosis result. 
     The diagnoser  260  determines that the cause of the drainage error is at least one of five typical fault causes, namely, excessive bubble generation, program malfunction, drainage malfunction  1 , drainage filter clogging, and drainage malfunction  2 . 
     The server controller  210  outputs at least one fault cause corresponding to the diagnosis result among the 5 fault causes through the server output device  270 . 
     That is, when the drainage error code has occurred due to two causes, excessive bubble generation and drainage filter clogging, the server controller  210  outputs the two fault causes, excessive bubble generation and drainage filter clogging, as diagnosis results. 
     When one item is selected from the output diagnosis result items, the server controller  210  displays a solution derived in response to the item. 
     When the cause of the drainage error is excessive bubble generation, the server controller  210  displays a solution of advising the user to again perform a drainage operation after bubbles disappear and then to use an appropriate amount of detergent since the error is caused by failure to completely remove bubbles. 
     The counselor of the service center  200  may check the displayed cause and diagnosis result of the error and provides voice guidance on the cause of and the solution to the error to the user connected through a telephone. 
     The server controller  210  outputs a solution of dispatching a service technician when the fault cause is program malfunction and outputs a solution of requesting that the user check the low supply voltage and check whether the drainage filter is clogged and clean the drainage filter when the fault cause is drainage malfunction. 
     The server controller  210  outputs a solution of requesting that the user check whether the hose is bent and check whether the drainage filter is clogged and clean the drainage filter when the fault cause is clogging of the drainage filter. The server controller  210  outputs a solution of requesting that the user check whether the drainage pump has frozen and allow, when the drainage pump has frozen, the home appliance to reattempt to perform the drainage operation after it has unfrozen, and also check whether the hose is bent. 
     As is apparent from the above description, the home appliance diagnostic system and method according to the present invention receives a sound signal output from the home appliance, extracts product information from the sound signal, diagnoses fault of the home appliance using data corresponding to an error code among a plurality of data included in the product information, and provides a solution to the fault. Therefore, the user can easily confirm and inspect the state of the home appliance. It is also possible to correctly diagnose an error associated with, especially, drainage. In addition, when there is a need to dispatch a service technician, it is possible to quickly perform a procedure for dispatching the service technician, thereby increasing user convenience and providing a customized after-sale service suitable for the state of the home appliance. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.