Abstract:
A communication system including a communication terminal apparatus and a wireless key apparatus in wireless communication is provided. The communication terminal apparatus includes a first communication unit operable to receive a first wireless signal, and a first control unit operable to determine a distance between the communication terminal apparatus and the wireless key apparatus based on the received first wireless signal, wherein the first control unit limits a predetermined function of the communication terminal apparatus based on determining the distance. The wireless key apparatus includes a second communication unit operable to receive a second wireless signal, and a second control unit operable to determine the distance between the communication terminal apparatus and the wireless key apparatus based on the received second wireless signal, whereby the second control unit decreases transmission power associated with the second communication unit based on the determined distance.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
   The present invention contains has recognized/(object) matter related to Japanese Patent Application JP 2004-195060 filed in the Japanese Patent Office on Jun. 30, 2004, the entire contents of which being incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates, for example, to a communication system suitable for being applied to an apparatus constituted by a communication terminal apparatus such as a mobile telephone terminal and a wireless key apparatus restricting the operation of the terminal apparatus and to a communication terminal apparatus and a wireless key apparatus constituting the communication system. 
   2. Description of the Related Art 
   In recent years, a mobile telephone terminal which is one of communication terminal apparatuses a user always taking along in possession has a trend such that various functions other than wireless telephone functions of primary functions are built-in so as to contain multi functions. 
   For example, there exists such a terminal in which a camera function carrying out a filming of a still picture and a moving picture, a recording and reproducing function of music data, a viewing and listening function of television broadcast or the like is built-in. 
   In addition, in recent years, there has been rapidly developing a mobile telephone terminal in which a function as a non-contacting IC card is built-in. This non-contacting IC card is utilized as a boarding ticket of transport facilities, a membership card, an employee ID card, a card for price settlement means at a shop or the like. In this case, an authentication process is carried out by performing wireless communication between adjacent reader and writer, so that it is easy-to-use as compared with a magnetic card or the like. It should be noted in a case when an IC card function unit is mounted in a mobile terminal that the IC card function unit is not always necessarily to have a card type shape. 
   And now, it is preferable for the mobile telephone terminal having multi functions in this manner to be carried out with a process in order to secure some kind or another security for preventing various functions provided in the terminal from being abused when the terminal is lost. In particular, in case of a terminal installed with an IC card function unit, there is a possibility that personal information stored as the IC card function is read out unjustly or unjust settlement or the like utilizing the IC card function is carried out, so that the necessity for a function for preventing the unjust use thereof is high. There are descriptions, for example, in patent documents 1 and 2 that a wireless card which forms a pair with respect to the mobile telephone terminal is prepared and authentication request is wireless-transmitted periodically from that wireless card such that the functions of mobile telephone terminal is made to be restricted in a case when collation with respect to the authentication request cannot be taken. 
   More specifically, in a case when the mobile telephone terminal and the wireless card exchange ID (identification information) inherent therein periodically and a favorable communication state is maintained, that is, in a case when the ID exchange is realized, the mobile telephone terminal carries out a normal operation. On the contrary, when it is a state where the ID cannot be exchanged, that is, when the communication state is deteriorated or the communication is cut off, the use of partial function in the mobile telephone terminal is to be limited. In other words, it is possible to execute function limitation after presuming a distance between the mobile telephone terminal and the wireless card by utilizing wireless communication characteristics such that a favorable communication is possible when communication distance between the mobile telephone terminal and the wireless card is short and the communication state becomes deteriorated when the communication distance becomes long. 
     FIG. 1  shows one example of state transition in a terminal function limitation disclosed in related Japanese Patent Application No. 2004-195059 which was filed by the same applicant.  FIG. 1  shows states of “page/page-scan mode”, “normal connection mode” and “low power consumption mode”. 
   In “page/page-scan”, the wireless card side performs transmission process of a transmission signal and the mobile telephone terminal side performs detection of aforesaid transmission signal such that it is attempted whether or not the connection of the wireless card and the mobile telephone terminal can be realized. It is needless to say that it is also possible that the mobile telephone terminal side performs the transmission process and the wireless card side detects the transmitted signal. 
   In “normal connection mode”, both apparatuses confirm authenticity of the connected partner and carry out a process for shifting to a low power consumption communication process if there is no problem. A sound telephone call period of a mobile telephone terminal or the like also lies in this state. 
   In “low power consumption mode”, both apparatuses carry out packet transfer with the connection partner intermittently and confirm whether or not the wireless connection between the wireless card and the mobile telephone terminal is maintained. 
   Procedures on the occasion when limiting the use of the mobile telephone terminal function by utilizing aforementioned three states will be described. 
   (1) If packet cannot be received in “normal connection mode” and “low power consumption mode” state for a certain predetermined time period, it is deemed to be a connection abnormality or a connection failure (Abnormal LinkLoss) and the connection of the wireless card with the mobile telephone terminal is cut off. 
   (2) Further, when this connection abnormality is detected, a lock timer is activated. It is defined that a lock timer is a time period after the connection abnormality is cut off until the function limitation of the mobile telephone terminal is carried out. 
   (3) Then, after the abnormality is cut off, it is shifted to from “normal connection mode” or “low power consumption mode” to “page/page-scan mode (4)” and the mobile telephone terminal or the wireless card attempts a reconnection (paging). 
   (4) Here, in a case when the paging is succeeded within lock timer period, the lock timer is reset and it is shifted to “normal connection mode” and an operation is repeated from aforementioned 1). 
   (5) In a case if the paging is not succeeded within lock timer period, the mobile telephone terminal is function-limited (locked). When this function limitation is applied, it may be constituted such that a warning notice rings from the wireless card (warning mode) when the paging is not succeeded within a certain predetermined time period after the lock timer is activated and further the function limitation of the mobile telephone terminal is carried out after the time period elapses. 
   (6) Here, if a function limitation is applied to the mobile telephone terminal once, the function limitation of the mobile telephone terminal will not be released so long as a reconnection is succeeded by the paging (in this case, it is shifted to a normal connection mode from the paging). 
   According to abovementioned method, for example, if a user carries a wireless card attached his body and goes away from a mobile telephone terminal by putting only the mobile telephone terminal somewhere as it is, the communication state is deteriorated according to the free space loss or the like, the detection of a packet which a partner device transmits becomes difficult, finally a connection abnormality cut off occurs and a function limitation is executed on the mobile telephone terminal. In this manner, it is possible to execute a function limitation on the mobile telephone terminal when the wireless card is far from the mobile telephone terminal by a constant distance. Further, in a case when a connection can be carried out again after the function limitation is executed, it is possible to release the function limitation automatically. In this manner, it is possible to operate the security function of the mobile telephone terminal without consciousness of a user. 
   [Patent Document 1] Jap. laid-open patent publication No. 2001-352579 
   [Patent Document 2] Jap. laid-open patent publication No. 2001-358827 
   SUMMARY OF THE INVENTION 
   However, the transmission power on an occasion of a wireless communication according to an existing technology or the present case is always fixed, so that when, for example, the mobile telephone terminal and the wireless card are apart by a certain constant distance, abnormal cut off (Abnormal LinkLoss) can be detected and a function limitation is executed if they are apart by the constant distance, but the function limitation executed on the other hand is also to be released by approximately the same distance. According to this fact, the function limitation is to be released also from a place in which the mobile telephone terminal is apart from the wireless card and there is a possibility that it is abused by others. 
   Also, it is preferable for an apparatus such as a wireless card which is used as a pair with the mobile telephone terminal that there are few troubles as much as possible for everyday use thereof. However, practically relatively large power consumption occurs when data for authentication or the like are always exchanged with the mobile telephone terminal, so that it is necessary to charge or exchange the battery frequently and there was a problem of taking a lot of trouble. 
   SUMMARY OF THE INVENTION 
   In view of aforesaid matters, the present invention has recognized that the function limitation can be performed at a place of a communication terminal apparatus of a mobile telephone terminal or the like with a constant distance far from a wireless key apparatus which restricts the operation of the communication terminal apparatus, also the function limitation cannot be made to be released until the communication terminal apparatus comes to exists in the vicinity of the wireless key after the function limitation is once performed and at the same time, the power consumption is kept to be low. 
   According to one exemplified embodiment of the present invention, there is proposed a system which is constituted by a communication terminal apparatus and a wireless key apparatus which can carry out a wireless communication with the communication terminal apparatus by a predetermined wireless communication system. The communication terminal apparatus is provided with a communication unit for carrying out a wireless communication by the predetermined wireless communication system, a distance judgment unit for judging a distance from the wireless key apparatus and a control unit for limiting a predetermined function in response to the distance judged by the distance judgment unit. Also, the wireless key apparatus is provided with a communication unit for carrying out a wireless communication by the predetermined wireless communication system and a distance judgment unit for judging a distance from said communication terminal apparatus. In the communication system according to one exemplified embodiment of the present invention, at least one of the communication terminal apparatus and said wireless key apparatus is provided with a transmission power changing unit for controlling transmission power of a wireless signal which the communication unit of the one of apparatuses, wherein the control unit of the communication terminal apparatus limits the predetermined function when it is judged by the distance judgment unit that a first distance is exceeded during a connection with the wireless key apparatus and also the transmission power changing unit changes the transmission power such that the communication-possible distance between the the communication terminal apparatus and the wireless key apparatus becomes a second distance which is shorter than the first distance. 
   The communication system according to one exemplified embodiment of the present invention controls the transmission power in response to the state by utilizing a phenomenon that the communication-possible distance between the communication terminal apparatus and wireless key apparatus changes according to the magnitude of the transmission power outputted from the communication means. More specifically, with respect to the transmission power on the occasion when a connection confirmation process is performed between the communication terminal apparatus and the wireless key apparatus, the transmission power when the function limitation is released is made smaller than the transmission power when the function limitation is performed. Further, after the function limitation is released, the original transmission power when the function limitation is executed is again restored by being increased. 
   By constituting in this manner, the function limitation is executed at a place apart from the wireless key apparatus by a constant distance for the communication terminal apparatus and the function limitation is not executed in a near region (for example, a distance where a user can directly operate the telephone terminal apparatus). Further, after the function limitation is executed once, the function limitation is not released until the telephone terminal apparatus comes to exist in a near region and it is possible to release the function limitation automatically if it becomes a distance where a user can operate it directly. 
   According to one exemplified embodiment of the present invention, after the function limitation is executed once, the function limitation is not released until the communication terminal apparatus comes to exist in the vicinity of a user and the function limitation is released automatically when it becomes a distance where a user can operate it, so that reliability of the security for the communication terminal apparatus and usability of the function limitation function are improved. 
   Also, it is possible to decrease the power consumption as compared with a conventional case of a constant transmission power by lowering the transmission power of reconnection in a state in which a function limitation is executed for the communication terminal apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram showing a state transition example disclosed in Jap. laid-open patent application No. 2005-19059; 
       FIG. 2  is a perspective view showing a system constitutional example according to one exemplified embodiment of the present invention; 
       FIG. 3  is a block diagram showing a constitutional example of a communication terminal apparatus according to one exemplified embodiment of the present invention; 
       FIG. 4  is a block diagram showing a constitutional example of a wireless key apparatus according to one exemplified embodiment of the present invention; 
       FIG. 5  is an explanatory diagram showing a usage example according to one exemplified embodiment of the present invention; 
       FIG. 6  is a block diagram showing a modified example of a wireless key apparatus (example integrated with head set) according to one exemplified embodiment of the present invention; 
       FIG. 7  is an explanatory diagram showing a usage example of the example in  FIG. 6 ; 
       FIG. 8  is an explanatory diagram showing a setting example of a security mode according to one exemplified embodiment of the present invention; 
       FIG. 9  is an explanatory diagram showing a transition example of a security mode by a communication mode according to one exemplified embodiment of the present invention; 
       FIG. 10  is a flowchart showing a mode selection process example according to one exemplified embodiment of the present invention; 
       FIG. 11  is a flowchart showing a scanning process example according to one exemplified embodiment of the present invention; 
       FIG. 12  is a flowchart showing a page transmission process example according to one exemplified embodiment of the present invention; 
       FIG. 13  is a timing diagram showing an example of a process state of a page transmission and a scanning according to one exemplified embodiment of the present invention; 
       FIG. 14  is a sequence diagram showing an example of a connection state according to one exemplified embodiment of the present invention; 
       FIG. 15  is a flowchart showing a shifting process example for low power consumption according to one exemplified embodiment of the present invention; 
       FIG. 16  is a sequence diagram showing a transmission example of a communication state message according to one exemplified embodiment of the present invention; 
       FIG. 17  is a flow chart of a process example in a low power consumption mode. 
       FIG. 18  is a flowchart showing a communication process example in a wireless key apparatus according to one exemplified embodiment of the present invention; 
       FIG. 19  is a sequence diagram showing a transmission example in a sniff state according to one exemplified embodiment of the present invention; 
       FIG. 20  is a flowchart showing a process example in a standby state according to one exemplified embodiment of the present invention; 
       FIG. 21  is a flowchart showing a mode selection process example on a terminal side according to another exemplified embodiment of the present invention; 
       FIG. 22  is a flowchart showing a mode selection process example on a wireless key apparatus side according to another exemplified embodiment of the present invention; 
       FIG. 23  is a flowchart showing an example of a mode selection state in case of  FIGS. 22 and 23 ; 
       FIG. 24  is a state transition diagram in a terminal function limitation according to one exemplified embodiment of the present invention; 
       FIG. 25  is a flowchart showing a function limitation process in a mobile telephone terminal apparatus according to one exemplified embodiment of the present invention; 
       FIG. 26  is a flowchart showing a transmission electric power control process in a wireless key according to one exemplified embodiment of the present invention; and 
       FIG. 27  is a sequence diagram of a function limitation operation according to one exemplified embodiment of the present invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, one examplified embodiment of the present invention will be explained with reference to  FIGS. 2 to 27 . 
   In the present invention, a wireless key apparatus carrying out a wireless communication with a mobile telephone terminal apparatus is prepared and it is constituted such that security lock of the mobile telephone terminal apparatus is to be carried out according to a wireless communication state of the both sides. 
     FIG. 2  is a diagram showing an example of an apparatus of the present invention. A wireless key apparatus  50  is prepared as a separate body with a mobile telephone terminal apparatus  10 . According to this example, the wireless key apparatus  50  is constituted in a smaller size as compared with the mobile telephone terminal apparatus  10  and, for example, it is constituted such that it is hung around the neck of a user by a neck strap  50   a  or the like and is made to be a small sized shape which a user can always wear. The wireless key apparatus  50  is arranged with a light emitting unit  55  and an operation unit  59  (constituted in  FIG. 2  such that they are push button shaped), and it is also constituted such that a terminal unit  56  for connecting with the mobile telephone terminal apparatus  10  is prepared. 
   As a mobile telephone terminal apparatus  10 , there is shown here an example of a general mobile telephone terminal. In the mobile telephone terminal apparatus  10 , there are arranged an antenna  11  for a wireless telephone communication, a speaker  14 , a microphone  15 , a display unit  16 , an operation unit (operation key)  17 , a light emitting unit  22  and the like. Also, a terminal unit  23  for connecting with the wireless key apparatus  50  is prepared. This terminal unit  23  may be used as an existing terminal which is prepared for the mobile telephone terminal apparatus  10  to be connected with a charger or various external apparatuses. Also, it may be constituted in the display unit  16  such, for example, that a security display  16   a  showing that it is in an operation under a state that security is assured as explained hereinafter and a display (not shown) showing a fact that a so-called security lock in which the operation is limited according to its security function is executed may be carried out. 
   Next, a constitutional example of the mobile telephone terminal apparatus  10  of the present invention will be explained with reference to  FIG. 3 . The mobile telephone terminal apparatus  10  of the present invention is provided with an antenna  11  for a wireless telephone communication for carrying out a wireless communication with a base station for a wireless telephone and the antenna  11  is connected to a communication circuit  12  for a wireless telephone communication. Then, it is constituted such that a wireless communication is carried out with the base station under a control of a control unit  19 . When a communication for a telephone call is carried out in the communication circuit  12 , received sound data are supplied to a sound data processing unit  13  so as to perform a receiving process of the sound data. Then, they are supplied to a speaker  14  to be outputted. Also, sound data supplied from a microphone  15  are processed by the sound data processing unit  13 . Then, they are supplied to the communication circuit  12  as sound data for transmission and are transmitted. 
   The mobile telephone terminal apparatus  10  is provided with a display unit  16  constituted by a liquid crystal display or the like and an operation unit  17  constituted by operation keys or the like. In the mobile telephone terminal apparatus  10 , it is possible to display a mail sentence, a picture screen accessed to the web or the like on the display unit  16  an input operation of a telephone number, a mail sentence or the like and various mode settings or the like can be carried out by an operation unit  17 . 
   These respective blocks in the terminal apparatus  10  are connected with the control unit  19  or the like by way of a control line  25 . Also, each block is constituted such that data transfer can be carried out by way of a data line  26  so as to store necessary data in a memory  18 . In the memory  18 , not only data necessary as a mobile telephone terminal are stored but also it is possible to store data necessary in an IC card function unit  40  which will be described later on. Also, a necessary data saving for executing a program and/or for realizing the security function thereof is/can be carried out in the memory  18 . 
   Also, the mobile terminal apparatus  10  is provided with a vibration unit  21  constituted by a vibration motor or the like which vibrates the terminal itself for carrying out notification of receiving signal by way of the telephone line to this terminal apparatus  10  and various warnings and a light emitting unit  22  constituted by a light emitting diode or the like. Then, the vibration and the light emission are carried out under a control of the control unit  19 . These vibration unit  21  and light emitting unit  22  are used as notification means for notifying receiving signal or the like for the mobile telephone terminal and they are used also for necessary warning means as a security function. It should be noted that it is possible to output warning sound from the speaker  14  or the like in a case when sound is to ring as necessary warning means in the security function. 
   Then, the mobile telephone terminal  10  of the present invention is provided with a communication circuit  32  for short distance wireless communication in addition to the communication circuit  12  for telephone communication Then, it is carried out by using this communication circuit  32  a wireless communication with a partner within a relatively narrow region of, for example, around from several meters to hundred meters at the maximum by way of a connected antenna  31  (however, it is constituted such that a process for narrowing the communication possible region is to be executed when carrying out a communication during a normal period with the wireless key apparatus as will be described later on). Here, for example, a wireless communication system for short distance referred to as Bluetooth® is applied. In this short distance wireless communication, various kinds of use applications are supposed such, for example, that a communication is carried out with a head set for a hands-free telephone call or a communication with a personal computer apparatus is carried out through the mobile telephone terminal apparatus  10 . As to the frequency band used for the wireless communication, for example, 2 GHz band is used, it is constituted such that a frequency band or modulation system which does not intervene in the wireless telephone communication in the communication circuit  12  is employed. According to this constitution, it is possible to carry out the wireless telephone communication in the communication circuit  12  and the communication in the communication circuit  32  for short distance wireless communication at the same time. 
   In case of this example, a wireless communication is carried out with a wireless key apparatus  50  by using this communication circuit  32  for short distance communication. However, a wireless communication is possible also with an apparatus (head set, personal computer apparatus or the like) other than the wireless key apparatus  50  if it is a communication apparatus of the same communication system. Also, in a case when a security function is executed, the wireless key apparatus  50  carrying out a wireless communication by the communication circuit  32  is to be limited to a specific one apparatus. For that purpose, for example, identification ID or the like of the apparatus is to be registered in the memory  18  or the like beforehand. With respect to registered information relating to this wireless key apparatus  50 , it may be constituted such that a user cannot revise it. 
   A transmission amplifier  33  which amplifies the transmission signal in the communication circuit  32  is constituted such that transmission power is to be set in a plurality of steps by the control of the control unit  19  or the like. Also, in a state in which it is wireless-connected with the wireless key apparatus  50 , it is constituted such that low transmission power among the plurality of steps is to be set. Further, in a state in which it is connected with an apparatus other than the wireless key apparatus  50 , transmission power of a relatively high step is to be set. It should be noted in a case when it is wireless-connected with an apparatus installed a function for a wireless key apparatus such as a head set which will be described later on that the transmission power is to be set depending on the operation state of the partner apparatus at that time (more specifically, depending on whether or not it is operated only as a wireless key apparatus or whether or not combined another function is operated). It will be described later on with respect to a concrete process example for setting the transmission power. 
   The mobile telephone terminal  30  of the present invention is provided with a non-contacting IC card function unit  40 . The non-contacting IC card function unit  40  includes a billing data control unit  41  connection with an antenna  42  and an adjacent wireless communication in a very adjacent distance of around several centimeters is carried out with reader and writer. In this adjacent wireless communication, it is possible to operate the billing data control unit  41  by means of the power obtained by receiving a radio wave from the reader and writer side, but according to this example, it is constituted such that the billing data control unit  41  is to be operated by the power supply supplied from a power supply circuit  24  in the mobile telephone terminal  10 . 
   When the IC card function is executed, the billing data control unit  41  reads out data necessary for billing or authentication from the memory  18  (or a memory in the billing data control unit  41  (not shown)) and an exchange of the read out data is carried out with the reader and writer by an adjacent wireless communication. For example, in a case when it is functioned as a boarding ticket of transport facilities, it is constituted such that the billing data control unit  41  transmits data charged amount of money or the like which is possible to be paid by direct debit for an effective zone and an effective period as a boarding ticket (commutation ticket) or as a boarding ticket or personal information or the like relating to a person possessing this terminal (IC card) to the reader and writer so as to carry out a billing process or an authentication process. In case of using an employee ID card, a membership card, a card for price settlement, a credit card or the like, necessary information for its authentication is also exchanged. 
   Further, it is constituted such that the mobile telephone terminal apparatus  10  of the present invention is provided with a terminal unit  23  and various peripheral apparatuses, data process apparatuses which are not shown or the like can be connected directly thereto by way of this terminal  23 . In this case, it is constituted such that power supply can be applied to external apparatuses connected by means of the terminal unit  23  from the power supply circuit  24  installed with a secondary battery or the like which applies power supply to respective portions in the mobile telephone terminal apparatus  10 . For example, as shown by an arrow J of a dotted line in  FIG. 2 , it is constituted in a case when the terminal unit  56  of the wireless key apparatus  50  and the terminal unit  23  of this mobile telephone terminal apparatus  10  are connected directly such that it is possible to supply power to a secondary battery in the wireless key apparatus  50  from the power supply circuit  24  in the mobile telephone terminal apparatus  10  so as to charge it. Also, it is constituted in a case when the wireless key apparatus  50  is connected directly to the terminal unit  23  of the mobile telephone terminal apparatus  10  such that the control unit  19  of the mobile telephone terminal apparatus  10  detects that fact and a security process when directly connected (for example, security process executed without short distance wireless communication which will be described later on) is to be carried out. 
   Next, it will be explained with respect to the constitution of the wireless key apparatus  50  which carries out a wireless communication with the mobile telephone terminal apparatus  10  according to the present invention with reference to  FIG. 4 . The wireless key apparatus  50  of the present invention is provided with a communication circuit  52  for short distance wireless communication. Then, by using this communication circuit  52 , a wireless communication is carried out with a partner in a relatively narrow region of, for example, around several meters and at the maximum hundred meters by way of a connected antenna  51  (however, it is constituted when communication is carried out normally with the mobile telephone terminal apparatus  10  such that a process for narrowing the communication possible region is executed). Here, it is constituted such that Bluetooth system which is a short distance wireless communication system provided on the mobile telephone terminal apparatus  10  side is also applied to the wireless key apparatus  50 . The partner carrying out a wireless communication by the communication circuit  52  is limited to a specific one of the mobile telephone terminal apparatus  10 . For that purpose, for example, the identification ID or the like of its apparatus was registered beforehand. With respect to the registered information as to the mobile telephone terminal apparatus  10 , it may be constituted such that a user cannot revise it. 
   With respect to the wireless communication in the communication circuit  52 , it is executed under a control of a control unit  53 . In this case, it is constituted such that transmission power is to be set in a plurality of steps in a transmission amplifier  52   a  which amplifies a transmission signal in the communication circuit  52  under a control of the control unit  53  or the like. Also, in a state where it is wireless-connected with the mobile telephone terminal apparatus  10 , a low transmission power is to be set in the plurality of steps. However, it is constituted in a case when the control unit  53  detects that an operation unit  59  (button shaped operation unit or the like as shown in  FIG. 2 ) arranged in the wireless key apparatus  50  is operated such that a process for heightening the transmission power temporarily in the transmission amplifier  52   a  is to be carried out. 
   The wireless key apparatus  50  of this example is provided with a warning sound creation unit  54  connected with a speaker  54   a  for outputting warning sound and a light emitting unit  55  constituted by a light emitting diode or the like. Then, output of the warning sound, vibration and light emission are carried out under the control of the control unit  53 . These warning sound creation unit  54  and light emitting unit  55  are used as warning means necessary for security function. Also, it is constituted such that the light emitting unit  55  functions also as display means which displays the security mode at present in a state where a wireless communication is carried out with the mobile telephone terminal apparatus  10  and the security function is operated. Specifically, for example, the light emitting unit  55  functions also as display means for displaying a security mode by changing the display such that when the light emitting unit  55  is blinking in green, it indicates that it is in a normal mode and when it is blinking in red, it indicates that it is in a warning mode, when there is no display at all, it indicates that it is in a function limitation mode, or the like. The display means for displaying the security mode may be constituted such that a liquid crystal display or the like is used and a display where modes can be recognized directly by characters and figures or the like is carried out. Also, it may be constituted as warning means for warning by vibration. 
   It is constituted such that the control unit  53  and each unit is connected by means of a control line  58  and a wireless communication in the communication circuit  52 , operations in the warning sound creation unit  54  and the light emitting unit  55  and the like are executed under a control of the control unit  53 . 
   Also, it is constituted such that the wireless key apparatus  50  of the present invention is provided with a terminal unit  56  and the mobile telephone terminal apparatus  10  can be connected directly by using this terminal  56 . When connected thereof, the control unit  53  in the wireless key apparatus  50  carries out a data transfer directly with the control unit  19  in the mobile telephone terminal apparatus  10  and carries out a security process when directly connected without carrying out a short distance wireless communication. Also, in a case when remaining charge amount of the secondary battery installed in a power supply circuit  57  in the wireless key apparatus  50  is small, it is possible to charge the secondary battery in the power supply circuit  57  by an power supplied from the side of the mobile telephone terminal apparatus  10 . 
   When the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  constituted in this manner are used, a user always carries the wireless key apparatus  50  as shown, for example, in  FIG. 5 . Then, it is constituted such that when the user uses the mobile telephone terminal apparatus  10 , the function is not to be limited (normal mode which will be described later on). Then, in a case when a user goes away from the mobile telephone terminal apparatus  10  by a distance of a certain degree after putting the mobile telephone terminal apparatus  10  somewhere in a state where the wireless key apparatus  50  is always maintained to be carried, a warning operation is executed from the wireless key apparatus  50  (warning mode which will be described later on). If he stays away from the mobile telephone terminal apparatus  10  in a state where the warning operation is executed, it becomes a state where the function of the mobile telephone terminal apparatus  10  is limited (function limitation mode which will be described later on). It should be noted with respect to the warning operation in a warning mode that it may be constituted such that it is to be carried out only on the side of the mobile telephone terminal apparatus  10 . Alternatively, it may be constituted such that the warning operation in the warning mode is to be carried out in both of the wireless key apparatus  50  and the mobile telephone terminal apparatus  10 . 
   With respect to a function of the mobile telephone terminal apparatus  10  which is limited in a function limitation mode, it is a choice, for example, to direct to all of the functions of the mobile telephone terminal apparatus  10  (however, communication function related to security function is not to be limited) and it is another choice to direct to a partial function within the function which the terminal apparatus  10  is provided with. Specifically, it may be constituted, for example, such that only the process using the non-contacting IC card function unit  40  is to be limited. Also, it may be constituted such that address book inspection of the mobile telephone terminal apparatus  10 , display of personal information of mail inspection or the like is to be limited. Also, it may be constituted such that only the reception of a signal can be allowed while the transmission as a wireless telephone is to be limited. Also, it may be constituted such that only the reception of a signal can be allowed while the transmission as a wireless telephone is to be limited. In this case, it may be constituted such that only the telephone number for emergency announcement to a police station or the like can be transmitted. Also, it may be constituted such that a process using the non-contacting IC card function unit  40  is not to be limited while only the function as a wireless telephone apparatus is to be limited. 
   The wireless key apparatus  50  explained so far was constituted as an apparatus for exclusive use which carries out only the security function, but it should be noted that it may be constituted such that it is to be mounted on an apparatus having other function. For example, it may be constituted such that a wireless key apparatus is to be mounted on a head set for carrying out a wireless communication of Bluetooth system with the mobile telephone terminal apparatus  10  and carrying out a so-called hands-free telephone call. 
     FIG. 6  is a diagram showing a constitutional example of a head set with this wireless key. A head set with a wireless key  60  according to the present invention is provided with a communication circuit  62  for short distance wireless communication. This communication circuit  62  carries out a wireless communication with a partner in a relatively narrow region of, for example, around several meters and at the maximum hundred meters by way of a connection antenna  61 . Here, Bluetooth system which is the same system as the short distance wireless communication system provided on the side of the mobile telephone terminal apparatus  10  is applied also to the communication circuit  62  of the head set with the wireless key. The partner carrying out a wireless communication by the communication circuit  62  is limited to the specific one of the mobile telephone terminal apparatus  10  which was registered. For that purpose, for example, identification ID of the apparatus or the like is registered beforehand. However, it may be constituted when using only the head set such that there is no limitation for the partner whom the communication circuit  62  carries out a wireless communication. 
   With respect to the wireless communication in the communication circuit  62 , it is executed under a control of the control unit  63 . In this case, it is constituted such that transmission power for the transmission amplifier  62   a  which amplifies the transmission signal in the communication circuit  62  is to be set under a control of the control unit  63  or the like. 
   When a communication for the head set (more specifically, sound data communication for a telephone call) is carried out in the communication circuit  62 , received sound data are supplied to a sound data processing unit  66  and a receiving process of the sound data is performed. Thereafter, they are supplied to a speaker  67  and outputted. Also, sound data picked up by a microphone  68  are processed in the sound data processing unit  66  so as to become sound data for transmission. Then, the sound data for transmission are supplied to the communication circuit  62  and transmitted. 
   In addition, the head set with the wireless key  60  of the present invention is provided with an operation unit  64  constituted by operation keys or the like, a memory  65  and a light emitting unit  70 . The light emitting unit  70  is used as warning means relating to the security function and at the same time used also as display means of operation state on the occasion when it is functioned as a head set. These respective units in the head set  60  can carry out exchange of control data by way of a control line  73 . Further, the respective units can carry out exchange of sound data or the like by way of a data line  74 . 
   Also, the head set with the wireless key  60  of the present invention is provided with a terminal unit  71  and it is constituted such that the mobile telephone terminal apparatus  10  can be connected directly by means of this terminal  71 . When connected with the mobile telephone terminal apparatus  10  directly, it is constituted such that the control unit  63  in the head set with the wireless key  60  carries out a data transfer directly with the control unit  19  in the mobile telephone terminal apparatus  10  and a direct sound data transfer or a security process is to be carried out without a short distance wireless communication. Also, in a case when remaining charge amount of a secondary battery installed in a power supply circuit  72  in the head set with the wireless key  60  is small, it is possible to charge the secondary battery in the power supply circuit  72  by an power supplied from the side of the mobile telephone terminal apparatus  10 . 
   In a case when such a head set with a wireless key  60  is prepared, as shown, for example, in  FIG. 7 , a user putting on the head set with the wireless key  60  can carry out a so-called hands-free telephone call depending on a fact that the mobile telephone terminal apparatus  10  which remains inside a bag or the like and the head set with the wireless key  60  carries out a wireless communication. Further, with respect to a function as a wireless key apparatus, a warning and a function limitation of the mobile telephone terminal apparatus  10  are executed according to position relationship (distance) between the head set with the wireless key  60  and the mobile telephone terminal apparatus  10 . More specifically, in a case when the mobile telephone terminal apparatus  10  goes away from the head set with the wireless key  60  to a certain degree of distance, the head set with the wireless key  60  or the mobile telephone terminal apparatus  10  (alternatively, both sides) carries out a warning operation (warning mode which will be described later on). Then, if the user stays away from the mobile telephone terminal apparatus  10  in the state in which this warning operation was carried out, it becomes a state in which the function of the mobile telephone terminal apparatus  10  is limited (function limitation mode will be described later on). 
   Next, it will be explained with respect to a process example in a case when a security process is carried out by preparing the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  of such a constitute. It should be noted that also a security process in case of using the head set with the wireless key  60  is basically similar, but it will be explained in the explanation hereinafter on the assumption that the wireless key apparatus  50  is used. 
   First, it will be explained with reference to  FIG. 8  with respect to a security process mode (hereinafter designates as security process mode). It is constituted in case of this example such that there are prepared a normal mode M 1  which does not limit the function of the mobile telephone terminal apparatus  10 , a warning mode M 2  for warning that it gets out of the normal mode caused by a fact that the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  goes away or the like and a function limitation mode M 3  for limiting the function of the mobile telephone terminal apparatus  10  in a case when it does not return to from the warning mode to the normal mode (more specifically, in a case when the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  remains in a far state). 
   With respect to the transition of these modes, there are, as shown by arrows in  FIG. 8 , a change from the normal mode M 1  to the warning mode M 2  and a change from the warning mode M 2  to the function limitation mode M 3  and further, it returns to the normal mode M 1  if the wireless key apparatus  50  approaches the mobile telephone terminal apparatus  10  in a state in which it became the function limitation mode M 3 . Further, it returns to the normal mode M 1  if the wireless key apparatus  50  approaches the mobile telephone terminal apparatus  10  in a state in which it became the warning mode M 2  and the warning operation is carried out. 
   In case of the present invention, these security modes are made to have relation with the communication modes prepared in the Bluetooth system which is a wireless communication system between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50 . More specifically, as communication modes in the wireless communication system (Bluetooth system) of this example are shown in  FIG. 9 , there is a connection mode M 11  for authenticating and wireless-connecting the partner apparatus in both of the mobile telephone terminal apparatus  10  and the wireless key apparatus  50 . When authentication is completed mutually and connection is carried out in the connection mode M 11 , it becomes a data transfer mode M 12  in which payload data transfer is carried out practically. When the data transfer is completed in the data transfer mode M 12 , it is shifted to a low power consumption communication mode M 13 . In this low power consumption communication mode M 13 , the wireless communications of both sides are carried out intermittently by a cycle longer than a communication cycle in the data transfer mode M 12  and it becomes a state in which the wireless connection between the both sides is maintained. Owing to the fact that the cycle carrying out the intermittent communication is long in this manner, it becomes possible to make the power consumption required for the communication smaller than a case in which it is operated in the data transfer mode M 12  and low power consumption is realized. It should be noted that the low power consumption here indicates a phenomenon that the low power consumption is realized by thinning out communication cycles and is not related directly to the process for lowering the transmission power which will be described later on (however, it is constituted as described later on such that a process for lowering transmission power is carried out during a low power consumption mode). 
   In a case when the data transfer between the both sides is to be restarted in a state of this low power consumption communication mode M 13 , it returns to the connection mode M 11 , a process for restarting the communication is carried out in the connection mode M 11  and thereafter it becomes the data transfer mode M 12  in which the data transfer is carried out practically. In a state in which the wireless connection is maintained in the low power consumption communication mode M 13 , the connection process in the connection mode M 11  is carried out relatively simply and it is possible to carry out the restart of the data transfer rapidly as compared with a case in which the wireless connection is recommenced. 
   Also, in a case when a connection process with anyone of communication partners is not carried out in the connection mode M 11  (or in a case when a connection is not possible), each apparatus is shifted to the standby mode M 14 . The apparatus which becomes this standby mode M 14  carries out an intermittent reception or transmission with a very long cycle and carries out a process for searching whether or not a communication apparatus to become a partner exists. Here, it may be constituted such that the apparatus becoming the standby mode M 14  does not return to the connection mode M 11  if there is no process which may become some kind or another opportunity caused by a user operation or the like. Also, during a period when a communication is carried out between two apparatuses, the two apparatuses are to be set in the same mode basically. More specifically, at least the connection mode M 11 , the data transfer mode M 12  and the low power consumption mode M 13  are the modes which shift in synchronism with each other between the two apparatuses. 
   Here, in case of the present invention, as shown in  FIG. 9 , the normal mode M 1  is set as a security mode when it is a state in which it communicated between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  in the low power consumption communication mode M 13  and a warning mode is started by an opportunity that the communication mode shifts from the low power consumption communication mode M 13  to the connection mode M 11 . The process with respect to the detail in which it is shifted from a warning mode to a function limitation mode will be described later on, but when the security mode becomes the function limitation mode M 3 , the function limitation mode M 3  remains during a period when it is the connection mode M 11 , the data transfer mode M 12  and the standby mode M 14 . It is constituted only in a case when it is shifted from the data transfer mode M 12  to the low power consumption communication mode M 13  such that the security mode is to return from the function limitation mode M 3  to the normal mode M 1 . 
   Next, it will be explained a process in which the security mode is selected in each of the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  with reference to  FIG. 10 . This security mode selection process is, for example, executed under the control of the control units  19  and  53  of the respective apparatuses. 
   First, it is judged whether or not the communication mode at present is in a low power consumption communication mode (step S 1 ). Here, in a case when it is in a low power consumption communication mode, a state timer prepared in the control unit is reset (step S 2 ). Then, the security mode is set to a normal mode (step S 3 ) and a process as a normal mode (more specifically, a mode without limiting the function) is executed (step S 4 ). It should be noted that the state timer is a timer counted up by passage of time. 
   Also, in a case when it is judged in step S 1  that it is not in a low power consumption communication mode, it is judged whether or not the security mode just before (at present) is a normal mode (step S 5 ). Here, in case of a normal mode, a state timer prepared in the control unit is made to start (step S 6 ). Then, a start of a warning mode is set (step S 7 ) and a warning operation as a warning mode is executed (step S 8 ). It should be noted that in a case when it is constituted such that only one of the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  carries out the warning operation, any process is not carried out particularly in the other apparatus during the warning mode. 
   Then, in a case when it is judged in step S 5  that the security mode just before (at present) is not a normal mode, it is judged whether or not the counted value of the state timer activated in step S 6  exceeds a value TH determined beforehand (step S 9 ). It remains in the warning mode of step S 8  until the counted value exceeds the predetermined value TH 1  and in a case when the counted value exceeds the predetermined value TH 1 , it is made to change the security mode to a warning mode (step S 10 ) It is designed such that the time period when the counted value of the state timer exceeds the predetermined value TH 1  after the count is started is a time period, for example, of around several seconds to several ten seconds. 
   Next, it will be explained with reference to the drawings of  FIG. 11  and subsequent thereto about a specific example of a communication state in each communication mode in each of the mobile telephone terminal apparatus  10  and the wireless key apparatus  50 . First, it will be explained an example in which the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  carry out the authentication process of a partner in the connection mode M 11 . In case of carrying out a wireless communication by Bluetooth system, one of the communication apparatus of the two apparatuses carrying out the communication becomes a master apparatus and the other communication apparatus becomes a slave apparatus. For the Bluetooth system, either one of the apparatuses may become a master or a slave, but in case of the present invention, it is to be set such that the wireless key apparatus  50  becomes a master and the mobile telephone terminal apparatus  10  becomes a slave. 
   The apparatus which became a slave (mobile telephone terminal apparatus  10  here) carries out a scan process for searching the master in a connection mode.  FIG. 11  is a flowchart showing an operation example in this scan process. In the scan process, continuous reception is carried out for a constant period and a process for searching a signal from the master is carried out (step S 11 ). It is judged in its scan process whether or not a signal (page signal) added with an ID number of the wireless key apparatus  50  which is a partner carrying out the security process was received (step S 12 ). Here, in a case when signal added with the ID number of the wireless key apparatus  50  is not received, it is shifted to an idle process so as to wait for a constant period (step S 13 ) and thereafter it returned to step S 11  such that the scan process is repeated. 
   Then, in a case when it is judged in step S 12  that the page signal added with the ID number of the wireless key apparatus  50  was received, a response signal with respect to that page signal is transmitted (step S 14 ) and it is shifted to a communication state by carrying out a connection process with the master (more specifically, shifted to a data transfer mode M 12 ) (step S 16 ). 
   Next,  FIG. 12  will be explained. The apparatus which became a master (here, wireless key apparatus  50 ) starts a standby timer when the connection mode starts (step S 21 ). A page signal is transmitted by a determined channel for a predetermined period (step S 22 ). At that time, for example, an ID number which was set for the own apparatus is added to the page signal and at the same time, the ID number of the communication partner is also added. Then, it is judged whether or not there is a response from the slave after the transmission of the page signal (step S 23 ). In case of no response, it is judged whether or not the counted value of the standby timer exceeds a determined time period TH 2  (step S 24 ). In a case when the counted value of the standby timer does not exceed the determined time period TH 2 , it is shifted to an idle process and it waits for a constant period (step S 25 ) and thereafter, it returns to step S 22  and the transmission process of the page signal is repeated. 
   Then, in a case when it is judged in step S 23  that there is a response from the slave, a connection process with the slave is performed and it is shifted to a communication state (more specifically, shifted to a data transfer mode) (step S 27 ). Also, in a case when the counted value of the standby timer exceeds the determined time period TH 2  in step S 24 , it becomes a standby state (step S 28 ) and a process for attempting a connection with the slave here is discontinued. 
     FIGS. 13A and 13B  are diagrams showing an example of a communication state between the apparatus which became the master (wireless key apparatus  50 ) in which the process of the flowchart in  FIG. 12  is carried out and the apparatus which became the master slave (mobile telephone terminal apparatus  10 ) in which the process of the flowchart in  FIG. 11  is carried out.  FIG. 13A  shows a transmission timing of the page signal and an idle period of the master (wireless key apparatus  50 ).  FIG. 13B  shows a receiving (scan) timing and an idle period of the slave (mobile telephone terminal apparatus  10 ). As shown in  FIGS. 13A and 13B , the idle period of the transmission side and the idle period of the receiving side are different from each other and it is constituted such that the page signal transmitted at any timings can be received on the receiving side. 
     FIG. 14  is a diagram showing the process of  FIG. 13  by a sequence diagram. As shown in  FIG. 14 , the transmission of the page signal is carried out from the wireless key apparatus  50  intermittently (at timing T 11 , T 12 , T 13 ). Here, if there is a response with respect to the page signal (at timing T 14 ), mutual exchange of the response between the two apparatuses are further carried out (at timing T 15 , T 16 ), thereafter mutual exchange of the connection signal performing the wireless connection is carried out (at timing T 17 , T 18 ) and it is shifted to a data transfer mode. 
   Next, a process example in a case when the respective apparatuses of the present invention are shifted to the data transfer mode M 12  will be explained with reference to a flowchart of  FIG. 15 . When it is shifted to a data transfer mode, an authentication process in a channel in which the data transfer is carried out is performed (step S 31 ). Then, it is judged whether or not the authentication was completed correctly (step S 32 ). In a case when the authentication process is not completed here, it returns to the connection mode M 11 . 
   Then, in a case when the connection process in step S 32  is completed, a data transfer is carried out ordinarily, but in the security process of the present invention, the data transfer is not carried out and a process for shifting to a low power consumption mode M 13  is carried out directly (step S 33 ). Then, it is judged whether or not it can be shifted to a low power consumption mode (step S 34 ). In case of a state in which it can be shifted to a low power consumption mode M 13 , it is set to a sniff state of a low power consumption mode M 13 . In a case when it cannot be shifted to a low power consumption mode, it returns to the connection mode M 11 . 
     FIG. 16  is a sequence diagram showing an example of the communication state shown in the flowchart of  FIG. 15 . More specifically, packet transmission is carried out mutually in the data transfer mode M 12  for performing authentication or the like (at timing T 21 , T 22 , T 23 , T 24 ). Then, after the authentication is completed, data (sniff mode request) for shifting to a low power consumption mode is transmitted (at timing T 25 ) from the master (wireless key apparatus  50 ) and its consent is received (at timing T 26 ) such that both apparatuses are shifted to a low power consumption mode (sniff mode). 
     FIG. 17  is a flowchart showing a process example in a low power consumption mode M 13  (sniff mode) relating to the slave (mobile telephone terminal apparatus  10 ). The process will be explained. When it becomes a sniff mode, first, a timer is started (step S 41 ) and a scan process for receiving a signal from the master is carried out (step S 42 ). It is judged subsequently to the scan process whether or not a signal (page signal) added with the ID number of the wireless key apparatus  50  which is a partner carrying out a security process was received (step S 43 ). Here, in a case when a signal added with the ID number of the wireless key apparatus  50  is received, a response signal with respect to the page signal is transmitted (step S 44 ). Then, the timer started in step S 41  is reset (step S 45 ) and it is shifted to an idle period (step S 46 ). When an idle period of a constant period elapses, it returns to the scan process in step S 42 . Here, in case of the present invention, it is constituted such that the idle period in step S 46  (period when communication is not carried out) is set as a relatively longer period and at the same time, it is constituted such that it is synchronized with the idle period on the master side. 
   On the other hand, in a case when it is judged in step S 43  that a signal added with the ID number of the wireless key apparatus  50  is not received, it is judged whether or not the timer started in step S 41  exceeded a predetermined value T_SV (step S 47 ). Then, in a case when it does not exceed the predetermined value T_SV, the flow is shifted to the idle process of step S 46 . Then, in a case when step S 47  it is judged it exceeds the predetermined value T_SV, the communication mode is changed to a connection mode M 11  (step S 48 ). The transmission power of the transmission amplifier may be changed to be higher when the communication mode is changed to a connection mode. 
     FIG. 18  is a flowchart showing a process example in the master (wireless key apparatus  50 ) with respect to the low power consumption mode (sniff mode). Its process will be explained. A first timer is started when it becomes a sniff mode (step S 51 ). Then, a process for transmitting a page signal for a predetermined period is carried out (step S 52 ). After the transmission of this page signal, it is judged whether or not a response from a partner (mobile telephone terminal apparatus  10 ) which carries out a security process was received (step S 53 ). Here, in a case when the response signal is receive, the timer started in step S 51  is to be reset (step S 54 ). Then, the flow is shifted to the idle period (step S 55 ). When an idle period of a constant period elapses, the flow returns to the page transmission process of step S 52 . Here, in case of the present invention, it is constituted such the idle period (period in which the communication is not carried out) in step S 55  is to be set as a relatively long period and at the same time is to be synchronized with the idle period on the slave side. 
   On the other hand, in a case when it is judged in step S 53  that a response from the mobile telephone terminal apparatus  10  is not received, it is judged whether or not the timer started in step S 51  exceeded a predetermined value T_SV (step S 56 ). In a case when it does not exceed the predetermined value T_SV, it is shifted to the idle process of step S 55 . Then, in a case when it is judged in step S 56  that the predetermined value T_SV is exceeded, the communication mode is changed to a connection mode M 11  (step S 57 ). When the communication mode is changed to a connection mode M 11 , the transmission power of the transmission amplifier may be changed to be high. 
     FIG. 19  is a sequence diagram showing communication timings in the both apparatuses in connection with a low power consumption mode (sniff mode) M 13 . As shown in  FIG. 19 , the timing at which the sniff process (portion describes as ON) is carried out in the master and the timing at which the sniff process is carried out in the slave approximately coincide with each other. More specifically, the timings (T 31 , T 33 , T 35 , T 37 ) at which polling packets are transmitted from the master and the periods when the reception thereof are carried out in the slave approximately coincide with each other. Also, respective polling packets are received by the slave and with respect to the responses thereof (at timing T 32 , T 34 , T 36 , T 38 ), they are received on the master side. Owing to the fact that an intermittent bidirectional communication is carried out in this manner, a low power consumption mode M 13  is maintained and a wireless connection state between the master and the slave is maintained. 
   It should be noted in a case when the communication mode becomes a standby state that, for example, a process shown in a flowchart of  FIG. 20  is carried out. More specifically, when it becomes a standby state, an activation period is set for an activation timer (step S 61 ). Then, the activation timer is started (step S 62 ). Then, the communication circuit is made to be in a sleep state (step S 63 ). Thereafter, when the period set by the activate timer elapses, the communication circuit is activated (step S 64 ) and the step is shifted to the connection mode M 11  so as to execute a connection process. 
   Owing to a fact that the processes explained so far are executed, in a case when the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  can wireless-communicate favorably in an adjacent state, the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  are maintained in a wireless-connected state using a low power consumption mode. In this wireless-connected state using the low power consumption mode, a data transfer which becomes a so-called payload is not carried out and a signal for maintaining the wireless connection is only transmitted and received intermittent. In this case, by selecting the idle period properly, it is possible to carry out a communication with very low power consumption. Therefore, it is possible to lower the power consumption caused by carrying out the security process of the present invention and it is possible to make the battery duration periods of both the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  be a longer period. In particular, there is a big effect on a wireless key apparatus which is desired to be constituted in a small size as much as possible. 
   Also, with respect to the mobile telephone terminal apparatus  10 , a security process was carried out by applying a short distance wireless communication system of the Bluetooth system which has a great number of examples already mounted on mobile telephone terminals, so that the security process of the present invention can be realized only by slightly changing a control constitution or the like of a mobile telephone terminal provided with a short distance wireless communication circuit of an existing Bluetooth system and a favorable security function is realized easily. 
   Here, in the exemplified embodiments mentioned above, it was constituted such that shifting from a low power consumption mode to a connection mode is processed (more specifically, processed according to the connection/cutoff of the communication or the signal strength) simply by whether or not it is a state in which a wireless communication is possible between two apparatuses, but it may be constituted such that it is judged by a detection state of packets from the partner.  FIGS. 21 to 23  are diagrams showing a process example in a case thereof. 
   First, a process example in a slave (mobile telephone terminal apparatus  10 ) is shown in a flowchart of  FIG. 21 . When the mobile telephone terminal apparatus  10  becomes in a low power consumption mode (sniff mode), a timer is started (step S 71 ). Then, “good” is set as a communicate state (step S 72 ). Then, a scan process for receiving a signal from a master is carried out (step S 73 ). It is judged in its scan process whether or not a signal (page signal) added with an ID number the wireless key apparatus  50  which is a partner carrying out a security process was received (step S 74 ). Here, in a case when a signal added with the ID number of the wireless key apparatus  50  was received, a response signal with respect to that page signal is transmitted (step S 75 ) and the timer started in step S 71  is reset (step S 76 ). Then, the flow is shifted to an idle period (step S 77 ). When the idle period of a constant period elapses, the flow returns to the scan process of step S 73 . This idle period is synchronized the idle period on the master side. 
   In a case when it is judged in step S 74  that the signal added with the ID number of the wireless key apparatus  50  cannot be received, it is judged whether or not the timer started in step S 71  exceeded a first predetermined value T_SV 1  (step S 78 ). In a case when the predetermined value T_SV 1  is not exceeded, it is shifted to the idle process of step S 77 . Then, in a case when it is judged in step S 78  that the predetermined value T_SV 1  was exceeded, the timer further judges whether or not a second predetermined value T_SV 2  was exceeded (step S 79 ). It should be noted that the second predetermined value T_SV 2  is a period longer than that of the first predetermined value T_SV 1 . Here, in a case when it is judged the second predetermined value T_SV 2  is not exceeded, “bad” is set as a communicate state (step S 80 ), it is shifted to the idle process of step S 77 . In a case when it is judged in step S 79  that the second predetermined value T_SV 2  was exceeded, the communication mode is changed to a connection mode (step S 81 ). 
   Next, a process example in a master (wireless key apparatus  50 ) here will be explained with reference to a flowchart of  FIG. 22 . When it becomes a sniff mode, a first timer is started (step S 91 ). Then, “good” is set as a communicate state (step S 92 ). Then, a process for transmitting a page signal for a predetermined period is carried out (step S 93 ). After the transmission of this page signal, it is judged whether or not a response from the partner (mobile telephone terminal apparatus  10 ) which carries out a security process was received (step S 94 ). Here, in a case when a response signal was received, the timer started in step S 91  is reset (step S 95 ) and the flow is shifted to an idle period (step S 96 ). When an idle period of a constant period elapses, the flow returns to the scan process of step S 93 . This idle period is synchronized with the idle period on the slave side. 
   Then, in a case when it is judged in step S 94  that a response from the mobile telephone terminal apparatus  10  cannot be received, it is judged whether or not the timer started in step S 91  exceeded a first predetermined value T_SV 1  (step S 97 ) In a case when the predetermined value T_SV 1  is not exceeded, the flow is shifted to an idle process of step S 96 . Then, in a case when it is judged in step S 97  that the predetermined value T_SV 1  was exceeded, it is further judged whether or not the timer exceeded a second predetermined value T_SV 2  (step S 98 ). It should be noted that the second predetermined value T_SV 2  is a period longer than that of the first predetermined value T_SV 1 . Here, in a case when it is judged that the second predetermined value T_SV 2  was not exceeded, “bad” as a communication state is set (step S 99 ). Then the flow is shifted to an idle process of step S 96 . In a case when it is judged in step S 98  that the second predetermined value T_SV 2  was exceeded, the communication mode is changed to a connection mode (step S 100 ). 
   Then, in case of being processed as shown in  FIGS. 21 and 22 , the security mode selection is to be set according to the judgment as shown in  FIG. 23 . More specifically, it is judged first whether or not the communication mode is a low power consumption mode (step S 101 ). In case of a low power consumption mode, it is judged whether or not the communicate state set by the flowchart of  FIGS. 21 and 22  is “good” (step S 102 ). Here, in a case when the communicate state is “good”, the security mode is made to be a normal mode M 11  (step S 103 ). Then, in a case when the communicate state is “bad” in step S 102 , the security mode is made to be a warning mode M 2  (step S 104 ). Further, in a case when it is judged in step S 101  that it is not a low power consumption mode, the security mode is made to be a function limitation mode M 3  (step S 105 ). 
   By being process as shown in the flowchart of  FIG. 23 , it becomes a warning mode in a state in which possibility of shifting from the low power consumption mode to the connection mode became high and it is possible to carry out a warning favorably. 
   Next, it will be explained with respect to an exemplified embodiment in a case when it is constituted when a function limitation is applied to the mobile telephone terminal apparatus  10  such that a transmission power is controlled on the occasion when a reconnection process is carried out between the mobile telephone terminal apparatus  10  and the wireless key apparatus  10 . 
   In  FIG. 24 , there exist four states of “page/page-scan (when the terminal is normal)”, “page/page-scan (when the terminal is locked)”, “normal connection mode” and “low power consumption mode”, and it will be explained with respect to these four states. 
   The “page/page-scan (terminal normally)” corresponds to a connection mode M 11  ( FIG. 9  see). In this case, it is still a state in which a function limitation is not applied to the mobile telephone terminal apparatus  10 . At that time, the wireless key apparatus  50  executes a transmission process and the mobile telephone terminal apparatus  10  detects a transmission signal from the wireless key apparatus  50  such that it is attempted whether or not the wireless key apparatus  50  and the mobile telephone terminal apparatus  10  are connectable there-between. It is needless to say that it may be constituted such that the side of the mobile telephone terminal apparatus  10  is to carry out the transmission process and the side of the wireless key apparatus  50  is to detect the transmitted signal. 
   The “page/page-scan (when the terminal is locked)” is a state in which a function limitation is applied to the mobile telephone terminal apparatus  10 . At that time, the wireless key apparatus  50  executes a transmission process and the mobile telephone terminal apparatus  10  carries out a detection of the transmission signal such that it is attempted whether or not the wireless key apparatus  50  and the mobile telephone terminal apparatus  10  are connectable there-between. Similarly as mentioned above, it may be constituted such that the side of the mobile telephone terminal apparatus  10  is to carry out the transmission process and the wireless key apparatus  50  is to detect the signal. 
   The “normal connection mode” corresponds to a data transfer mode M 12  (see  FIG. 9 ) or to a transition period from the data transfer mode M 12  to the low power consumption communication mode M 13 . In this case, the authenticity of the connected partner is confirmed and if there is no problem, a process for carrying out a shift to a low power consumption communication process is performed. A state in which a sound telephone call of the mobile telephone terminal apparatus  10  is under an operation or the like lies in this state. 
   The “low power consumption mode” corresponds to the low power consumption communication mode M 13  (see  FIG. 9 ). In this case, an intermittent packet transfer is carried out and it is confirmed whether or not a wireless connection between the wireless key apparatus  50  and the mobile telephone terminal apparatus  10  is maintained. 
   It will be explained by utilizing aforementioned four states about the function limitation procedure of the mobile telephone terminal apparatus. 
   &lt;Prerequisite&gt; 
   
       
       0) It is assumed that an arbitrary transmission power is set in the states of “normal connection mode” and “low power consumption mode”.
 
For example, if the mobile telephone terminal apparatus and the wireless key apparatus are away from each other by around 50 m, it is adjusted to take a transmission power such that an abnormal cutoff occurs. At that time, it is not always necessary that both of the mobile telephone terminal apparatus and the wireless key apparatus are set for this transmission power. It is allowed that either one is to be adjusted to this transmission power. Here, it is assumed that the transmission power of the wireless key apparatus side is adjusted.
 
     
  
   The distance between the aforementioned mobile telephone terminal apparatus and the wireless key apparatus can be calculated by analyzing a wireless state of a signal received in the communication circuits  32  and  52  for short distance of each apparatus, for example, by analyzing a signal strength or the like in the control units  19  and  53  of each apparatus. Also, by comparing with an initial value under a predetermined condition given beforehand, it can be judged whether the distance between the mobile telephone terminal apparatus and the wireless key apparatus at present is farer or nearer than a predetermined distance. 
   &lt;Flow after Function Limitation Until Function Limitation Release&gt; 
   1) In a state of “normal connection mode” or “low power consumption mode”, if a user goes away from the mobile telephone terminal apparatus  10  in a state in which a user is carrying the wireless key apparatus  50  and puts only the mobile telephone terminal apparatus  10  somewhere, the communication state becomes deteriorated according to a free space loss or the like. In this case, it becomes difficult to detect the packet which the partner apparatus transmitted and it becomes impossible finally to receive the packet. Then, if the packet cannot be received normally for a certain predetermined time period, the connection between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  will be cut off for the reason that both of the apparatuses are in a state of connection abnormality or connection failure (abnormal cutoff). 
   2) Further, when this abnormal cutoff is detected, a lock timer is activated. It is defined in this example such that the lock timer is a time period after the connection abnormality or the connection failure occurs until the function limitation of the mobile telephone terminal apparatus  10  is carried out. 
   3) Then, it is shifted after the abnormal cutoff to the state of “page/page-scan” and the mobile telephone terminal apparatus  10  or the wireless key apparatus  50  attempts a reconnection (paging). 
   4) In a case if the paging is successful within the lock timer period, the lock timer is reset and it is shifted to “normal connection mode” so as to repeat the operation from the aforementioned 1). 
   5) On the other hand, in a case when the paging is not successful within the lock timer period, a function limitation (lock) is applied to the mobile telephone terminal apparatus  10 . Further, the transmission power of the wireless key apparatus  50  is lowered. For example, the transmission amplifier  52   a  is set according to the control of the unit  53  and the transmission power on the side of the wireless key apparatus  50  is lowered until it becomes a transmission power by which a connection cannot be executed unless the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  is within 1 m. 
   6) If a user is approaching to the mislaid mobile telephone terminal apparatus and the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  (user) approaches within 1 m, the connection becomes possible again. 
   7) If the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  succeed in the connection, the step is shifted to “normal mode”. The function limitation of the mobile telephone terminal apparatus  10  is to be released. Then, in order to apply the function limitation by 50 m again, the transmission power of the wireless key apparatus  50  is to be increased until it becomes a power with which the function limitation is applied by 50 m. 
   It may be constituted such that the control of the abovementioned transmission power is carried out only in one of the wireless key apparatus  50  and the mobile telephone terminal apparatus  10  or in both the apparatuses. 
   According to the above operation, the function limitation is applied at a place far from the user (the wireless key apparatus  50 ) by a constant distance and the function limitation is not applied in the vicinity of the user. Further, after the function limitation is applied to the mobile telephone terminal apparatus  10  once, the function limitation is not to be released until the mobile telephone terminal apparatus  10  comes to exist in the vicinity of the user. Then, if the user comes to approach to the vicinity thereof and it becomes a distance in which the user can operate the mobile telephone terminal apparatus  10 , the function limitation is released automatically, so that it is possible to improve the usability and the reliability of the function limitation function of the mobile telephone terminal apparatus  10 . 
     FIG. 25  is a flowchart showing a transmission power control process of the wireless key apparatus in a state transition shown in  FIG. 24 . The initial state is a normal connection mode (step S 201 ). In this mode, the authenticity of the connected partner is confirmed and if there is no problem, a process is carried out for shifting to a low power consumption communication process. It becomes this state also during a sound telephone call period or the like. It is judged for a predetermined time whether or not there is a necessary process such as a sound telephone call or the like (step S 202 ) and if there is no necessary process, the step is shifted to a low power consumption mode (step S 203 ). 
   After shifting to the low power consumption mode, it is judged for a predetermined time whether or not there exists a receiving signal (step S 204 ). If the transmission signal from the mobile telephone terminal apparatus  10  cannot be received normally for a predetermined time for the reason that the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  becomes away or the like, the connection between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  will be cut off for the reason that it is in a state of connection abnormality or connection failure (abnormal cutoff). At the same time, a lock timer is activated (step S 205 ). Here, it is defined such that the lock timer is a time period after the connection abnormality or the connection failure occurs until the terminal function limitation is carried out. 
   After the connection abnormality or the connection failure occurs, the step is shifted to a page/page-scan mode (when the terminal is normal) (step S 206 ) and a reconnection with the mobile telephone terminal apparatus  10  is attempted (paging). 
   Then, it is judged whether or not the paging was successful (step S 207 ). If the paging is successful within the lock timer period and the reconnection with the mobile telephone terminal apparatus  10  can be executed, the lock timer is released (reset) (step S 208 ) and the step is shifted to a normal connection mode of step S 201 . In a case when the paging failed, it is judged whether or not the time period of the lock timer elapsed (step S 209 ) and if it did not elapse, the flow is shifted to step S 207  and the paging is continued. 
   Then, if the reconnection cannot be attained within the lock timer period after the aforementioned connection abnormality or the connection failure, the wireless key apparatus  50  sets the transmission amplifier  52   a  and lowers the transmission power (step S 210 ). Then, the flow is shifted to a page/page-scan (when the terminal is locked). For example, the transmission power at that time is made to be a transmission power such that the paging cannot be executed if the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  is within 1 m. 
   The reconnection with the mobile telephone terminal apparatus  10  is attempted in a state in which the transmission power of the wireless key apparatus  50  is lowered and is judged whether or not the paging was successful (step S 211 ). The distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  again becomes in the vicinity of a user (in this example, when it becomes within a 1 m region), the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  are reconnected (success of paging). Then, the wireless key apparatus  50  increases the transmission power such that the function limitation can be applied to the mobile telephone terminal apparatus  10  by a distance of 50 m again. Then, the step is shifted to the normal connection mode of step S 201  and the abovementioned sequential processes are repeated. 
     FIG. 26  is a flowchart showing a function limitation control process of the mobile telephone terminal apparatus in the state transition shown in  FIG. 24 . In  FIG. 26 , processes from step S 221  to S 229  corresponds to the processes from step S 2011  to S 209  in  FIG. 25 . 
   In  FIG. 26 , the initial state is a normal connection mode (step S 221 ). In this mode, the authenticity of the connection partner is confirmed and if there is no problem, a process for shifting to a low power consumption communication process is carried out. It is judged whether or not there is a necessary process such as a sound telephone call or the like for a predetermined time period (step S 222 ) and if there is no necessary process, the step is shifted to a low power consumption mode (step S 223 ). 
   After shifting to the low power consumption mode, it is judged for a predetermined time period whether or not there exists a receiving signal (step S 224 ). If the transmission signal from the wireless key apparatus  50  cannot be received normally for a predetermined time period owing to a fact that the distance with respect to the mobile telephone terminal apparatus  10  becomes apart or the like, the connection between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  is cut off for the reason of connection abnormality or connection failure (abnormal cutoff). At the same time, a lock timer is activated (step S 225 ). 
   After a connection abnormality or a connection failure occurs, the step is shifted to a page/page-scan mode (when the terminal is normal) (step S 226 ) and a reconnection with the wireless key apparatus  50  is attempted (paging). 
   Then, it is judged whether or not the paging was successful (step S 227 ). If the paging is successful within the lock timer period and a reconnection with the wireless key apparatus  50  can be executed, lock timer is reset (step S 228 ) and the step is shifted to a normal connection mode of step S 221 . In a case when the paging was failed, it is judged whether or not the lock timer period elapsed (step S 229 ). If it did not elapse, the flow is shifted to step S 227  and the paging is continued. 
   Then, if a reconnection cannot be executed within the lock timer period after the aforementioned connection abnormality or connection failure, a function limitation is applied to the mobile telephone terminal apparatus  10  (step S 230 ). At that time, the transmission power of the wireless key apparatus  50  is lowered as mentioned above to a transmission power, for example, such that the paging cannot be executed if the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  is not within (step S 210  in  FIG. 25 ) and it is shifted to a page/page-scan (terminal lock). 
   The mobile telephone terminal apparatus  10  attempts the reconnection with the wireless key apparatus  50  in a state in which the transmission power of aforementioned wireless key apparatus  50  is lowered and it is judged whether or not the paging was successful (step S 231 ). If the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  again becomes in the vicinity a user (in this example, when it becomes within 1 m region), the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  are reconnected (success of paging). Then, the function limitation of the mobile telephone terminal apparatus  10  is released (step S 232 ). At that time, the transmission power is increased on the side of the wireless key apparatus  50  such that a function limitation is to be applied to the mobile telephone terminal apparatus  10  again by a distance of 50 m (step S 212  in  FIG. 25 ). Then, the mobile telephone terminal apparatus  10  is shifted to a normal connection mode of step S 201  and the abovementioned sequential processes are repeated. 
   It was shown in  FIG. 25  and  FIG. 26  with respect to the function limitation and transmission power control processes on an occasion of low power consumption mode and it is needless to say that similar processes are carried out also on an occasion of a normal connection mode in a case when a connection abnormality or a connection failure is detected. 
   Also, the processes of the function limitation release and the transmission power increase for the mobile telephone terminal apparatus  10  were carried out after the success of the paging, but it is not always necessary to execute this just after the success of the paging and it is possible to carry out the function limitation release of the mobile telephone terminal apparatus  10  when the authentication operation is ended, when it is shifted to a low power consumption or the like. 
     FIG. 27  a sequence diagram showing a function limitation operation of the mobile telephone terminal apparatus and the wireless key apparatus in this exemplified embodiment. As mentioned above, the transmission power of the wireless key apparatus  50  is adjusted to a transmission power as prerequisite such that a communication cannot be performed if the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  become apart by around 50 m. 
   First, both the apparatuses of the mobile telephone terminal apparatus  10  and the mobile key apparatus  50  confirm the authenticity of the connected partner each other in a “normal connection mode” communication and if there is no problem, a process for shifting to a low power consumption communication process is carried out. A state in which a sound telephone call is under an operation or the like lies in this state. 
   In the “low power consumption mode” communication, both the apparatuses carry out transmission and reception of packets intermittently and confirm whether or not the wireless connection is maintained. 
   Thereafter, if the user carrying the wireless key apparatus  50  goes away from the mobile telephone terminal apparatus  10  and is far from it by around 50 m, the detection of the packet which the partner apparatus transmitted becomes difficult and it becomes impossible to receive the packet finally. 
   Then, if the packet cannot be received normally for a predetermined time, both the apparatuses of the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  cut off the connection for the reason of a connection abnormality or a connection failure (abnormal cutoff). At the same time, if this connection abnormality or connection failure occurs, both of the apparatuses start respective lock timers. 
   If the reconnection cannot be executed within the lock timer period even if the reconnection is attempted after the detection of the connection abnormality or the connection failure, a function limitation is applied to the mobile telephone terminal apparatus  10 . Further, the transmission power of the wireless key apparatus  50  is lowered to a transmission power by which a connection cannot be attained if, for example, the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  is not within 1 m. At that time, it is possible to notify to the user by using the speaker  54   a  or light emitting unit  55  of the wireless key apparatus  50   a  about a fact that the transmission power was lowered or the mobile telephone terminal apparatus  10  of the connection partner in a lock state. 
   The mobile telephone terminal apparatus  10  and the wireless key apparatus  50  will try the reconnection also after the function limitation of the mobile telephone terminal apparatus  10  is applied. Then, if the user again approaches to the mobile telephone terminal apparatus  10  and the mobile telephone terminal apparatus  10  and the wireless key apparatus  50  (user) approach within 1 m, the reconnection (paging) becomes successful. 
   If the reconnection was successful, the function limitation of the mobile telephone terminal apparatus  10  is released. Further, by setting the transmission amplifier  52   a  of the wireless key apparatus  50 , the transmission power is increased until a power by which a function limitation can be applied by 50 m. By repeating the above sequence, the execution and the release of the function limitation in the mobile telephone terminal apparatus  10  are carried out in response to the distance between the mobile telephone terminal apparatus  10  and the wireless key apparatus  50 . 
   As mentioned above, the present invention controls the transmission power in response to the state by utilizing a phenomenon that the communication possible distance between the apparatuses changes according to the amount of the transmission power of the communication apparatus by the Bluetooth system. Specifically, it is constituted with respect to the transmission power on the occasion when processing a connection confirmation between the apparatuses such that the transmission power of at least either one of the communication apparatuses is made smaller relating to the transmission power when the function limitation is released than the transmission power when the function limitation is applied. Further, after the function limitation is released, it is again increased to the original transmission power when the function limitation is applied. 
   Owing to this fact, the mobile telephone terminal apparatus  10  is applied with a function limitation at a place far from the wireless key apparatus  50  by a constant distance and a function limitation is never applied in an near region (for example, in a distance in which a user can operate the mobile telephone terminal apparatus directly). Further, after the function limitation is applied once, the function limitation is not released until the mobile telephone terminal apparatus  10  comes to exist in a near region and if it becomes a distance in which the user can operate it, it is possible to release the function limitation automatically, so that it is possible to improve the usability and the reliability of security of the function limitation function in the mobile telephone terminal apparatus  10 . 
   Further, according to the present invention, it is possible by lowering the transmission power of the reconnection in a state in which the function limitation is applied to the mobile telephone terminal apparatus  10  to decrease the power consumption compared with that in a case of a conventional transmission using a constant power. Also, in a case when it was constituted such that the transmission power control is carried out in both of the mobile telephone terminal apparatus  10  and the wireless key apparatus  50 , it is possible to hold down the power consumption relating to the transmission on the occasion of the function limitation as compared with that in a case when the transmission power control is carried out only on one side. 
   It should be noted in the above mentioned exemplified embodiment that short distance wireless communication means by Bluetooth system or the like is installed in the mobile telephone terminal apparatus  10  and that short distance wireless communication means is used for actuating the security mode, but it may be constituted, for example, such that the short distance wireless communication means is not to be installed in the mobile telephone terminal apparatus  10  and short distance wireless communication means is to be connected to the mobile telephone terminal apparatus  10  externally. More specifically, it may be constituted, for example, such that two of apparatuses corresponding to the wireless key apparatus are prepared and one of the two wireless key apparatuses is connected to the mobile telephone terminal  10  and the security mode is to be set according to the communication mode in the two of the wireless key apparatuses. 
   Also, in the exemplified embodiment explained so far, a communication circuit of a Bluetooth system was installed in a mobile telephone terminal such that a wireless communication is to be carried out with the wireless key apparatus by that communication circuit, but it may be constituted such that a wireless communication is to be carried out with the wireless key apparatus by means of another wireless communication system. 
   Also, in case of the Bluetooth system, one of the apparatus which carry out a communication becomes a master and the other one becomes slave and to make the above mentioned wireless key apparatus side be a master and to make the mobile terminal side be a slave is only one example and it is allowed to reverse the relation there-between. Also, it may be constituted such that the master and the slave are counterchanged on the communication halfway. 
   Also, in the exemplified embodiment mentioned above, it was applied to the security assuring process of the mobile telephone terminal apparatus, but it may be constituted such that it is applied to a process for assuring the security of other mobile type. 
   Further, also with respect to the wireless key apparatus, an example which was constituted as a key apparatus for exclusive use was employed in the exemplified embodiment mentioned above, but it may be constituted such that a program which makes if function as a key apparatus of the present invention is installed to a terminal apparatus capable of communicating by the Bluetooth system or the like (for example, PDA apparatus or the like) so as to function as a key apparatus. 
   Also, the present invention is not limited to above mentioned exemplified embodiments and is applicable to a portable communication terminal other than a mobile telephone terminal apparatus such as, for example, a mobile information terminal (PDA), a mobile type personal computer or the like, and it is needless to say that other various kinds of constitutions can be adapted without departing from the scope of the present invention. 
   It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.