Abstract:
There is provided a wireless communication apparatus, which is capable of suppressing a burst noise emitted due to data transfer during wireless communication, thereby enhancing communication quality. The wireless communication apparatus transmits and receives a speech signal using a radio wave. Data to be displayed on the display screen is stored in a storage device. The stored data is transferred to the display device. Data displayed on the display screen of the display device is periodically updated based on the transferred data. A CPU monitors a wireless communication state of the wireless communication apparatus and stops the data transfer based on the monitored wireless communication state.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a wireless communication apparatus, a cordless telephone, a display operation control method, a program, and a storage medium. In particular, the present invention relates to a wireless communication apparatus and a cordless telephone, which are comprised of a slave unit and a master unit, with which the slave unit located remotely from the master unit performs conversation with an opposite party by using a wireless radio wave through the master unit connected to a telephone line, a display operation control method, a program for implementing the method, and a storage medium storing the program.  
           [0003]    2. Description of the Related Art  
           [0004]    A conventional wireless communication apparatus such as a cordless telephone has a function called “carrier sense” of detecting in advance whether the frequency of each conversation channel is being used, when starting communication using the communication apparatus, and selecting a vacant channel that is not currently used while avoiding other channels that are currently used by other cordless telephones, to thereby guarantee a normal communication operation.  
           [0005]    Even if conversation is started using the channel selected by the above carrier sense function or carrier sense, if a noise that has such a low level as is not detected by the carrier sense function occurs and in particular the noise has burst-like regularity, the noise acts as an annoyance for the conversation, resulting in degraded conversation quality. Such a noise does not raise a serious problem with monochrome displaying using a small-sized display, because the amount of data transferred to the display is small. Therefore, the occurrence of noise during conversion using a wireless communication apparatus has conventionally been suppressed by the following prior art methods.  
           [0006]    Japanese Laid-Open Patent Publication (Kokai) No. 2001-332994 discloses a small-sized wireless apparatus as represented by a cellular phone, in which to suppress a noise generated from a logic circuit in a receiving section of the wireless apparatus, the power supply is stopped to a data conversion section, an LCD driver input/output control section, and the like that are not directly related to a receiving operation.  
           [0007]    Japanese Laid-Open Patent Publication (Kokai) No. 07-336520 discloses a facsimile machine having a cordless telephone, in which to prevent occurrence of a noise from a facsimile section whose operation clock has a high frequency, control is provided such that a CPU of the facsimile section is set in a non-operating mode when no facsimile operation is carried out.  
           [0008]    Japanese Laid-Open Patent Publication (Kokai) No. 08-293839 discloses a cordless telephone equipped with a facsimile, in which to prevent the intrusion of a noise from the facsimile system into the cordless telephone system, a CPU that controls the facsimile reception is put into a halt state when facsimile transmission/reception is not carried out.  
           [0009]    Further, Japanese Laid-Open Patent Publication (Kokai) No. 11-127300 discloses a facsimile machine having a cordless telephone, in which oscillation of an IC that is a source of a radiant noise is stopped in advance in order to prevent the noise from interfering with the operation of a control channel of the cordless telephone. To this end, the supply of a clock to a logic IC of an image processor is stopped when the facsimile machine is on standby, and further, the cordless telephone is inhibited from being used during a copy operation and copying is inhibited from being carried out when the control channel of the cordless telephone is used for phone conversion.  
           [0010]    In recent years, however, with advancement of information and communication technology in the field of wireless communication apparatuses (cordless telephones, for example), communication carriers and the like have launched new services for browsing information using fixed-line phones. With such surfaces, phone displays have developed from monochrome display to color display, which has led to an increased amount of data transferred to the displays, and as a result, the above noise problem has become more serious. That is, the performance of wireless communication apparatuses (cordless telephones, for example) has been enhanced so that the amount of data required for displays has increased to several tens as large as the previously required amount. In addition, the data transfer speed has further increased and hence the data amount has increased, which results in burst-like noise occurring during wireless communication.  
           [0011]    Also, the displays have become capable of carrying out color displaying to cope with wait screens and moving screens such as a screen saver, so that burst-like data is periodically transferred via system buses.  
         SUMMARY OF THE INVENTION  
         [0012]    It is an object of the present invention to provide a wireless communication apparatus, which is capable of suppressing a burst noise emitted due to data transfer during wireless communication, thereby enhancing communication quality, a cordless telephone, which is capable of suppressing a burst noise emitted due to data transfer on a master unit side thereof, thereby enhancing conversation quality, a display operation control method which has solved the above described problems, a program for implementing the method, and a storage medium storing the program.  
           [0013]    To attain the above object, in a first aspect of the present invention, there is provided a wireless communication apparatus that transmits and receives a speech signal using a radio wave, comprising a display device having a display screen, a storage device that stores data to be displayed on the display screen, a transfer device that transfers the stored data, a display control device that periodically updates data displayed on the display screen of the display device based on the transferred data, and a control device that monitors a wireless communication state of the wireless communication apparatus and stops the data transfer by the transfer device based on the monitored wireless communication state.  
           [0014]    To attain the above object, in a second aspect of the present invention, there is provided a cordless telephone comprising a master unit having a display screen, at least one slave unit, a speech signal being transmitted and received between the master unit and the slave unit using a radio wave, a storage device that stores data to be displayed on the display screen of the master unit, a transfer device that transfers the stored data, a display control device that periodically updates data displayed on the display screen of the master unit based on the transferred data, and a control device that monitors a state of wireless communication between the master unit and the slave unit and stops the data transfer by the transfer device based on the monitored wireless communication state.  
           [0015]    Preferably, the control device is responsive to start of conversion using the slave unit, for stopping transfer of various types of data including the data to be displayed.  
           [0016]    Preferably, the control device stops the data transfer by the transfer device upon lapse of a predetermined delay time after the wireless communication state changes to a conversation state.  
           [0017]    Preferably, the display control device is responsive to start of conversion using the slave unit, for updating data displayed on the display screen of the display device displayed by the master unit such that the display screen is switched from a display showing that the slave unit is receiving an incoming call to a display showing that the slave unit is busy, and wherein the control device is responsive to start of conversion using the slave unit, for stopping the data transfer by the transfer device, and is responsive to the conversion using the slave unit being ended, for resuming the data transfer.  
           [0018]    To attain the above object, in a third aspect of the present invention, there is provided a method of controlling display operation of a wireless communication apparatus that transmits and receives a speech signal using a radio wave, comprising the steps of storing data to be displayed on a display screen of the wireless communication apparatus, transferring the stored data, periodically updating data displayed on the display screen of the wireless communication apparatus based on the transferred data, and monitoring a wireless communication state of the wireless communication apparatus and controlling stoppage and resumption of the data transfer based on the monitored wireless communication state.  
           [0019]    To attain the above object, in a fourth aspect of the present invention, there is provided a method of controlling display operation of a cordless telephone that transmits and receives a speech signal using a radio wave between a master unit and a slave unit thereof, comprising a storage step of storing data to be displayed on a display screen of the master unit, a transfer step of transferring the stored data, a display control step of periodically updating data displayed on the display screen of the master unit based on the transferred data, and a control step of monitoring a wireless communication state between the master unit and the slave unit and controlling stoppage and resumption of the data transfer based on the monitored wireless communication state.  
           [0020]    Preferably, the control step comprises stopping transfer of various types of data including the data to be displayed, in response to start of conversation using the slave unit.  
           [0021]    Preferably, the control step comprises stopping the data transfer in the transfer step upon lapse of a predetermined delay time after the wireless communication state changes to a conversation state.  
           [0022]    Preferably, the display control step comprises updating data displayed on the display screen of the display device displayed by the master unit such that the display screen is switched from a display showing that the slave unit is receiving an incoming call to a display showing that the slave unit is busy, in response to start of conversion using the slave unit, and wherein the control step comprises stopping the data transfer by the transfer device in response to start of conversion using the slave unit, and resuming the data transfer in response to the conversion using the slave unit being ended.  
           [0023]    To attain the above object, in a fifth aspect of the present invention, there is provided a wireless communication apparatus that transmits and receives a speech signal using a radio wave, comprising a display device having a display screen, an expanding device that expands data to be displayed on the display screen, a transfer device that transfers the expanded data, a display control device that updates data displayed on the display screen based on the transferred data, a monitoring device that monitors a wireless communication state of the wireless communication apparatus, and a stopping device that stops the data transfer, wherein when the wireless communication apparatus is in the wireless communication state, the stopping device stops the data transfer by the transfer device and the display control device causes the display device to continue displaying based on data that has been already transferred.  
           [0024]    Preferably, the expanding device expands the data to be displayed on the display screen based on state information indicative of the wireless communication state monitored by the monitoring device, and wherein when the wireless communication apparatus is in the wireless communication state, the display control device causes the display device to carry out displaying based on the state information which has been updated, and thereafter the stopping device stops the data transfer by the transfer device.  
           [0025]    Preferably, the monitoring device monitors states of the wireless communication apparatus including the wireless communication state, wherein the expanding device expands the data to be displayed on the display screen based on state information indicative of the wireless communication state of the wireless communication apparatus monitored by the monitoring device, and wherein when the wireless communication apparatus is in the wireless communication state, the display control device causes the display device to carry out displaying based on the state information which has been updated, and thereafter the stopping device stops the data transfer by the transfer device.  
           [0026]    Preferably, the wireless communication apparatus is a cordless telephone comprising a master unit, and at least one slave unit, and wherein the speech signal is transmitted and received using the radio wave between the master unit and the slave unit.  
           [0027]    More preferably, the wireless communication state is a state where conversation using the master unit and the slave unit is being carried out.  
           [0028]    To attain the above object, in a sixth aspect of the present invention, there is provided a method of controlling display operation of a wireless communication apparatus that transmits and receives a speech signal using a radio wave, comprising an expanding step of expanding data to be displayed on a display screen of the wireless communication apparatus, a transfer step of transferring the expanded data, a display control step of updating data displayed on the display screen based on the transferred data, a monitoring step of monitoring a wireless communication state of the wireless communication apparatus, and a stopping step of stopping the data transfer, wherein when the wireless communication apparatus is in the wireless communication state, the data transfer is stopped in the stopping step and displaying is continued based on data that has been already transferred in the display control step.  
           [0029]    Preferably, the expanding step comprises expanding data to be displayed on the display screen based on state information indicative of the wireless communication state monitored in the monitoring step, and when the wireless communication apparatus is in the wireless communication state, displaying is carried out based on the state information which has been updated in the display control step, and thereafter the data transfer is stopped in the stopping step.  
           [0030]    Preferably, the monitoring step comprises monitoring states of the wireless communication apparatus including the wireless communication state, wherein the expanding step comprises expanding data to be displayed on the display screen based on state information indicative of the wireless communication state monitored in the monitoring step, and wherein when the wireless communication apparatus is in the wireless communication state, displaying is carried out based on the state information which has been updated in the display control step, and thereafter the data transfer is stopped in the stopping step.  
           [0031]    Preferably, the wireless communication apparatus is a cordless telephone comprising a master unit, and at least one slave unit, and wherein the speech signal is transmitted and received using the radio wave between the master unit and the slave unit.  
           [0032]    More preferably, the wireless communication state is a state where conversation using the master unit and the slave unit is being carried out.  
           [0033]    To attain the above object, the present invention further provides a computer-readable program for implementing the display operation control method according to any of the third, fourth and sixth aspects.  
           [0034]    According to the present invention, it is possible to suppress a burst noise emitted due to data transfer during wireless communication by the wireless communication apparatus, thereby enhancing the communication quality. Also, during phone conversation using the cordless telephone, it is possible to suppress a burst noise emitted due to data transfer on the master unit side, thereby enhancing the conversation quality. That is, only while the slave unit is in a conversation state, the data transfer is stopped. As a result, it is possible to suppress a burst noise emitted due to data transfer.  
           [0035]    Also, even if the state of the apparatus changes, it is possible to continue the display while suppressing a burst noise emitted due to data transfer to the display device. This provides an excellent effect that the user can easily grasp the current state of the apparatus without difficulty.  
           [0036]    Also, the present invention provides an excellent effect that even if the state of the apparatus changes, the up-to-date state of the apparatus can be displayed while suppressing a burst noise emitted due to data transfer to the display device.  
           [0037]    Also, the operative state (status) of the apparatus, for example, is monitored to stop transfer of various types of data and control can be provided in response to change in the operative state. Further, to prevent the phenomenon that the display screen is not switched when the data transfer is stopped simultaneously with a change in the operative state, for example, the phenomenon that the display screen continues to show that the slave unit is ringing even after the slave unit enters a conversion state, display switching control is provided to switch the display screen with a predetermined delay time. As a result, it becomes possible to satisfy all requirements.  
           [0038]    Also, the display operation control method according to the present invention can be implemented by software, which can dispense with hardware measures such as shielding the substrate, filtering, or changing the frequencies to prevent interference.  
           [0039]    The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0040]    [0040]FIG. 1 is a view showing the configuration of a facsimile machine (FAX) equipped with a cordless telephone as a wireless communication apparatus according to an embodiment of the present invention;  
         [0041]    [0041]FIG. 2 is a block diagram showing the internal construction of a master unit  100  appearing in FIG. 1;  
         [0042]    [0042]FIG. 3 is a block diagram showing the internal construction of a slave unit  110  appearing in FIG. 1;  
         [0043]    [0043]FIGS. 4A and 4B are flowcharts showing an operation process carried out by the master unit  100  and the slave unit  110  when phone conversation using the slave unit  110  is being carried out, showing processing from stoppage of transfer of display data to the process returning to a standby state after the conversation is ended, in which:  
         [0044]    [0044]FIG. 4A shows processing carried out on the master unit  100  side; and  
         [0045]    [0045]FIG. 4B shows processing carried out on the slave unit  110  side;  
         [0046]    [0046]FIGS. 5A and 5B are flowcharts showing continued parts of the operation process in FIGS. 4A and 4B, which are carried out by the master unit  100  and the slave unit  110  when phone conversation using the slave unit  110  is being carried out, showing processing from the stoppage of the display data transfer to the process returning to the standby state after the conversation is ended, in which:  
         [0047]    [0047]FIG. 5A shows processing carried out on the master unit side; and  
         [0048]    [0048]FIG. 5B shows processing carried out on the slave unit  110  side; and  
         [0049]    [0049]FIGS. 6A and 6B are timing charts showing a relation between data transfer via a system bus  215  and noise occurring during phone conversation, in which:  
         [0050]    [0050]FIG. 6A shows a case where the data transfer via the system bus  215  is carried out; and  
         [0051]    [0051]FIG. 6B shows a case where the data transfer via the system bus  215  is stopped. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0052]    The present invention will now be described in detail with reference to the drawings showing a preferred embodiment thereof. FIG. 1 shows the configuration of a facsimile machine (FAX) equipped with a cordless telephone as a wireless communication apparatus according to the present embodiment. In FIG. 1, reference numeral  100  denotes the facsimile machine (master unit of the cordless telephone) according to the present embodiment, and reference numeral  110  denotes a slave unit of the cordless telephone.  
         [0053]    The master unit  100  includes a display section  101 , an operating section  102 , a handset  103 , and a master unit antenna  104 , and is connected to a public line via a wire communication line  130 . The master unit antenna  104  is used for wireless communication through the slave unit  110 . The display section  101  is comprised of a color LCD. On the other hand, the slave unit  110  of the cordless telephone includes a display  111 , an operating section  112 , and a slave unit antenna  113 . The slave unit antenna  113  is used for wireless communication with the master unit  100 .  
         [0054]    [0054]FIG. 2 is a block diagram showing the internal construction of the master unit  100 . The master unit  100  performs control of the main body of the facsimile machine, communication line control, control of wireless communication with the slave unit  110 , and the like, and is comprised of a CPU  201 , a ROM  202 , a RAM  203 , an LCD controller  204 , the display device section (display section)  101  such as a color LCD, the operating section  102 , a reading section  207 , a recording section  208 , a modem section  209 , a communication line interface (I/F)  210 , a wireless communication section  211 , a system bus  215 , and the master unit antenna  104 . The CPU  201  has incorporated therein a DMA controller for carrying out DMA transfer from the RAM  203  to the LCD controller  204 .  
         [0055]    The ROM  202  stores a system program and display data. The RAM  203  provides a work area for operation, a work area for a display screen, and an area for backup data. The wireless communication section  211  communicates with the slave unit  110  of the cordless telephone. Also, the CPU operates in accordance with the program in the ROM  202  to monitor a wireless communication state, that is, determine whether the master unit  100  and the slave unit  110  are currently carrying out wireless communication, monitor the states of the recording section  208 , the reading section  207 , and the like to check the presence of a recording sheet, the presence of an original, the presence of a paper jam, the presence of ink in the recording section  208 , and the like.  
         [0056]    [0056]FIG. 3 is a block diagram showing the internal construction of the slave unit  110 . The slave unit  110  is comprised of a CPU  301 , a ROM  302 , a RAM  303 , a baseband section  304  that performs speech processing, a wireless section  305  that performs modulation/demodulation, the slave unit antenna  113 , the display  111 , and the operating section  112 .  
         [0057]    Next, a description will be given of a display operation process carried out by the master unit  100  constructed as described above. This display operation process is for displaying on the screen of the display section  101  contents (presence of a recording sheet, presence of an original, occurrence of jamming, presence of ink in the recording section  208 , etc.) to be checked by monitoring the aforementioned states (the state of wireless communication between the master unit  100  and the slave unit  110 , the states of the recording section  208 , reading section  207  and others, etc.) by the CPU  201 .  
         [0058]    The ROM  202  stores in advance data used to display these contents on the screen of the display section  101 . Specifically, the ROM  202  stores data used to display “no paper” on the screen of the display section  101  when sheets have been exhausted, and data used to display “the slave unit is busy” on the screen of the display section  101  when the slave unit  110  enters a conversion state.  
         [0059]    The display data is transferred from the ROM  202  to the RAM  203  (video RAM) through block transfer using the system bus  215  and is expanded as graphic data onto the RAM  203 . The RAM  203  is composed of an SDRAM. The data, which is an assembled set of data for one display screen, is transferred from the RAM  203  to the LCD controller  204  through DMA transfer. The data transferred to the LCD controller  204  is further transferred to the display section  101  to carry out drawing on the display section  101 . The above operation is repeated periodically to realize screens such as a moving wait screen and a screen saver. All screens to be displayed on the display section  101  are displayed in the same manner as mentioned above.  
         [0060]    [0060]FIGS. 4A and 4B and FIGS. 5A and 5B are flowcharts showing an operation process carried out by the master unit  100  and the slave unit  110  when conversation using the slave unit  110  is being carried out. The flowcharts show processing from stoppage of transfer of display data to the process returning to a standby state after the conversation is ended. FIGS. 4A and 5A show processing carried out on the master unit  100  side, while FIGS. 4B and 5B show processing carried out on the slave unit  110  side. Programs that realize the present operation process are stored in the ROM  202  of the master unit  100  and the ROM  302  of the slave unit  110  and are executed by the CPUs  201 ,  301 , respectively. First, it is assumed that the master unit  100  is in a standby state. Then, a wait screen is displayed on the display section  101  of the master unit  100  (step S 1 ). As an example of the wait screen, the state of the recording section  208  or the reading section  207  may be displayed. In the wait screen displaying process, the display data for the wait screen is read out from the ROM  202 , transferred from the ROM  202  to the video RAM  203  through block transfer using the system bus  215 , and expanded as graphic data onto the video RAM  203 , as described above. Then, items of the display data are assembled into data for one screen as the wait screen, and transferred to the LCD controller  204  through the next DMA transfer. The data transferred to the LCD controller  204  is further transferred to the display section  101  for drawing and displayed by the display section  101 .  
         [0061]    Then, it is determined whether an incoming call has been detected (step S 2 ). If there is no incoming call, the process returns to the step S 1 . On the other hand, if there is an incoming call, an incoming call operation and an incoming call displaying operation are carried out at the same time (step S 3 ). In the present embodiment, upon detection of an incoming call, an incoming call ringing or the like is detected and display of the incoming call is carried out. This incoming call display process is carried out in the same manner as the wait screen display process described above.  
         [0062]    Then, the slave unit  110  is activated by the incoming call (step S 4 ). According to an incoming call connection request from the master unit  100  to the slave unit  110 , channel search is started. Specifically, carrier detection is carried out by the wireless communication section  211  to detect whether or not another cordless telephone is currently being used, and if the detection result is affirmative, further detect whether or not an interfering wave exists within the band of the channel being used by the other cordless telephone (step S 5 ). Then, after a carrier is detected, a usable channel is determined (step S 6 ).  
         [0063]    On the other hand, when receiving information on the usable channel from the master unit  100 , the slave unit  110  also carries out carrier detection and interference wave detection. If there is a channel that can be used by the slave unit  110 , the slave unit  110  is caused to start ringing (step S 21 ). If the slave unit  110  responds to the incoming call (step S 22 ), the master unit  100  captures the line (step S 7 ), a conversation path is formed between the master unit  100  and the slave unit  110 , and the slave unit  110  enters a conversation state.  
         [0064]    The master unit  100  changes the screen on the display section  101  to a display screen showing that the slave unit is in a conversation state (step S 8 ). Specifically, the display screen is switched by the same method as used to display the wait screen described above. If the display operation is continued, that is, if the DMA transfer of the graphic data from the RAM  203  to the LCD controller  204  is continued, a noise that has a level too low to be detected by carrier sense occurs even if the slave unit  110  enters a conversation state. The noise forms an annoyance during conversation and is recognized by the user. The noise is generated on the system bus  215  in synchronism with timing in which the display data is transferred to the LCD controller  204 . Here, the noise generated on the system bus  215  is emitted via the entire system bus  215  and therefore exerts a greatly adverse influence on a wireless device such as the slave unit  110 .  
         [0065]    To solve this problem, the display method is changed only during conversation using the slave unit  110  (step S 9 ). More specifically, in the display process, as described above, graphic data to be displayed during the conversation using the slave unit  110  is transferred from the ROM  202  to the video RAM  203  through block transfer, expanded onto the video RAM  203 , further transferred to the LCD controller  204  through DMA transfer, and the data transferred to the LCD controller  204  is further transferred to the display section  101  for drawing. In the step S 9 , the display data transfer timing is delayed by a predetermined time period in synchronism with the change in the status, i. e., the shifting to the conversation using the slave unit  110 , and then the transfer of the display data is stopped. Accordingly, the block transfer from the ROM  202  to the RAM  203  is stopped and the DMA transfer from the RAM  203  to the LCD controller  204  is also stopped. As a result, burst-like data transfer, which otherwise periodically takes place on the system bus  215 , ceases to take place so that no noise is generated from the system bus  215 . On the other hand, the LCD controller  204  includes a memory that accumulates the transferred data and the data transfer is carried out via a dedicated bus from the LCD controller  204  to the LCD (display section)  101 , so that displaying is continued. The influence exerted by only the transfer of display data using the dedicated bus from the LCD controller  204  to the LCD  101  on a wireless device, such as the slave unit  110 , is small. The first reason for this is that the transfer distance is short in the transfer using the dedicated bus between the LCD controller  204  and the LCD  101  and therefore the noise emission area is very narrow compared with the transfer using the system bus. The second reason is that even if a noise occurs that exerts an influence on a wireless device such as the slave unit  110 , the dedicated bus between the LCD controller  204  and the LCD  101  is usually formed by a cable, and therefore the noise occurrence can be easily coped with by merely using a noise canceling component part such as a core. The third reason is that the data transfer between the LCD controller  204  and the LCD  101  is usually not so fast as the transfer via the system bus, and therefore a large timing delay margin is allowed and hence the influence can be eliminated by taking measures to make the noise waveform blunt. Further, if the data transfer is stopped simultaneously upon the status change, i.e., the shifting to conversation using the slave unit  110 , there is a fear that the display screen is not switched. Therefore, as described above, to prevent the display screen showing that the slave unit is ringing from being continuously displayed even after the slave unit  110  enters a conversation state, control is provided such that the display data transfer is stopped with a delay of a predetermined time period, that is, the display screen showing “the slave unit is ringing” is switched to a display screen showing “the slave unit is busy” before the display data transfer is stopped. By thus stopping the display data transfer after a delay of a predetermined time period (that is, after the display screen showing “the slave unit is ringing” is switched to a display screen showing “the slave unit is busy”, it is possible to reliably switch from the display screen showing “the slave unit is ringing” to the display screen showing “the slave unit is busy”. Also, in the present embodiment, prior to stopping the transfer of display data in the step S 9  in FIG. 5A (that is, prior to stopping the transfer of the display data from the RAM  203  to the LCD controller  204 ), the process for displaying the conversation state of the slave unit is carried out in step S 8 . Due to this process, a delay is surely obtained to ensure the switching of the display screen with reliability, thus informing the user of the up-to-date state of the apparatus. Although in the present embodiment, the transfer of display data is stopped after the switching to the display screen showing “the slave unit is busy”, the present invention is not limited to such displaying of the conversation state of the slave unit  110 . Alternatively, the transfer of display data may be stopped after the up-to-date state of the apparatus after some change, for example, (“automatic-answering telephone is operating”, “no paper”, “no ink”, for example), is reflected upon the display screen. Further, although in the step S 8 , the transfer of display date is stopped after the displaying of the conversation state of the slave unit, the present invention is not limited to this, but a certain delay time period that is sufficient for switching the display screen showing “slave unit is ringing” to the display screen showing “the slave unit is busy” may be counted. and the data transfer may be stopped when the counted delay time period has elapsed.  
         [0066]    Referring again to FIGS. 5A and 5B, since the display screen should remain unchanged during the conversation using the slave unit  110 , the current display screen is continuously displayed. When the conversation using the slave unit  110  is ended (step S 23 ), the master unit  100  releases the line (step S 10 ). Then, the apparatus returns to the standby state, the display data to be displayed is returned to data to be displayed by an ordinary display method, and an ordinary wait screen is displayed (step S 11 ). Thereafter, the present display operation process carried out by both the slave unit  110  and the master unit  100  is terminated.  
         [0067]    [0067]FIGS. 6A and 6B are timing charts showing the relationship between data transfer via the system bus  215  and a noise occurring during conversation. As shown in FIG. 6A, at the time of data transfer via the system bus  215 , while data transfer to the display section  101  is being periodically carried out, a RSSI signal (Received Signal Strength Indicative Signal) having a waveform illustrated in the figure is output outputted from the wireless communication section  211 . In synchronism with the waveform of the RSSI signal, a noise occurs in communication data received by the master unit antenna  104 . In FIG. 6B, when the data transfer via the system bus  215  is stopped, no noise is generated in the output of the wireless communication section  211 . How the noise interferes with the reception is simply shown by the arrow in FIG. 2. The noise is caused by a change in a signal on the system bus  215  due to operations of the CPU  201 , the ROM  202 , the RAM  203 , and the LCD controller  204 , and the noise flies to the master unit antenna  104 .  
         [0068]    In the present embodiment, an example has been given, in which data transfer to the display device of the master unit  100  is stopped during communication between the master unit  100  and the slave unit  110  of the cordless telephone. However, the present invention is not limited to this. For example, it may be configured such that during communication between these two wireless communication apparatuses, the CPU of one of the wireless communication apparatuses stops transfer of data to be displayed on the display device of the wireless communication apparatus. Further, the construction of the one wireless communication apparatuses may be changed to a construction where the recording section  208  and the reading section  207  are removed from the master unit  100  shown in FIG. 2.  
         [0069]    The present invention is not limited to the construction of the above described embodiment and is applicable to any other construction insofar as it is possible to achieve the functions described in the appended claims or the functions provided by the construction of the above described embodiment.  
         [0070]    For example, although in the above described embodiment, only the transfer of display data is stopped, alternatively, the transfer of various other kinds of data that can cause noise during phone conversation may be stopped.  
         [0071]    Further, although in the above described embodiment, the present invention is applied to a facsimile machine equipped with a cordless telephone, the present invention is not limited to this, but may be applied to a cordless telephone itself or to a cordless automatic answering telephone having an automatic answering function. As a further alternative, the present invention may be applied to any other type of wireless communication apparatus insofar as it has a display device.  
         [0072]    Furthermore, it is to be understood that the object of the present invention may also be accomplished by supplying a system or an apparatus such as the master unit  100  with a storage medium in which a program code of software which realizes the functions of the above described embodiment is stored, and causing a computer (or CPU or MPU) of the system or apparatus to read out and execute the program code stored in the storage medium.  
         [0073]    In this case, the program code itself read from the storage medium realizes the functions of the above described embodiment, and hence the storage medium on which the program code is stored constitutes the present invention.  
         [0074]    Examples of the storage medium for supplying the program code include a floppy (registered trademark) disk, a hard disk, an optical disk, a magnetic-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD-RW, a DVD+RW, a magnetic tape, a nonvolatile memory card, in addition to a ROM as used in the above described embodiment. Alternatively, the program code may be downloaded via a network.  
         [0075]    Moreover, it also goes without saying that the functions of the embodiments described above may be realized not necessarily by causing the computer to read and execute the program code, but alternatively by causing an operating (OS) system running on the computer to perform part or all of the actual processing based on instructions in the program code.