Pager and time display method for pager which can display both local time and base time

A pager which can display base time in the base area of the pager along with displaying corrected local time in an area in which the pager is located is presented. The pager receives a country code and an area code transmitted by a paging system. A system information detection section judges whether or not the received country code and area code are the same as a country code and an area code corresponding to the base area of the pager. If the received country code and area code did not match, the CPU of the pager searches a time difference table for a piece of time difference information, based on the received country code and area code. The CPU judges whether or not the time difference information acquired by the search is the same as time difference information which has been stored in a time difference information memory section. If the time difference information acquired by the search is not the same, the local time which is clocked by a local clock section is corrected based on the acquired time difference information and the base time which is clocked by a base clock section. The CPU displays the local time clocked by the local clock section and the base time clocked by the base clock section on an LCD.

BACKGROUND OF THE INVENTION
 The present invention relates to a pager which is supposed to be used in a
 wide area, and in particular, to a pager which is provided with functions
 for automatically correcting the time of day which is clocked by a clock
 section of the pager.
 DESCRIPTION OF THE PRIOR ART
 In these days, pagers for receiving radio selective calling from a paging
 system are widely used around the world. The pager is generally provided
 with a clock section for clocking the time of day in an area in which the
 pager is located. However, in the case of paging systems in Europe, in the
 United States, etc., there exist time differences between countries or
 areas (states etc.), and thus the user of the pager has to frequently
 correct the time which is clocked by the clock section if the user carries
 the pager across areas having time differences.
 To resolve the problem, pagers which automatically correct the time clocked
 by the clock section have been proposed, as disclosed in Japanese Patent
 Application Laid-Open No.HEI6-188814 etc. The pager disclosed in the
 document receives an area code (indicating an area in which the pager is
 located) which is periodically transmitted by the paging system, and
 automatically corrects the time clocked by the clock section based on time
 difference information which is obtained by searching a time difference
 table using the received area code.
 However, such a conventional pager is generally provided with only one
 clock section. Therefore, when the pager received an area code that is
 different from an area code which has been stored in the pager, the area
 code stored in the pager is updated to the newly received area code and
 the time clocked by the only one clock section is corrected (updated) to
 the time of day in the area corresponding to the received area code, and
 the updated local time is displayed by a display section such as an LCD
 (liquid crystal display) to the user. Therefore, when such a pager
 received a different area code, only the local time (i.e. the time of day
 in an area corresponding the received area code) is displayed to the user,
 and the user can not see the base time or the original time, that is, the
 time of day in the base area of the pager (i.e. the time of day in the
 area in which the pager has been distributed to the user).
 SUMMARY OF THE INVENTION
 It is therefore the primary object of the present invention to provide a
 pager which can automatically correct the time of day clocked by the clock
 section to the local time in the area in which the pager is located
 immediately and correctly and display the corrected local time, and which
 can also display the base time in the base area of the pager to the user.
 Another object of the present invention is to provide a time display method
 for a pager, by which the time of day clocked by the clock section of the
 pager can automatically be corrected to the local time in the area in
 which the pager is located immediately and correctly and the corrected
 local time can be displayed, and by which the base time in the base area
 of the pager can also displayed to the user.
 In accordance with a first aspect of the present invention, there is
 provided a pager for receiving radio selective calling from a paging
 system, comprising a base area code memory means, a time difference table
 storage means, a base clock means, a local clock means, a code reception
 means, a code matching judgment means, a time difference information
 searching means, a time difference information matching judgment means, a
 time difference information memory means, a local time correction means,
 and a time display means. The base area code memory means prestores a
 country code and an area code which indicate the base area of the pager.
 The time difference table storage means prestores a table including
 country codes and area codes of a plurality of countries and areas and
 time difference information of each country/area in comparison with a
 reference time such as the GMT (Greenwich Mean Time). The base clock means
 clocks base time, which is the time in the base area of the pager. The
 local clock means clocks local time, which is the time in an area in which
 the pager is located. The code reception means receives a country code and
 an area code which are transmitted by a base station of the paging system.
 The code matching judgment means judges whether or not the country code
 and the area code received by the code reception means are the same as the
 country code and the area code stored in the base area code memory means.
 The time difference information searching means searches the time
 difference table storage means for a piece of time difference information
 based on the country code and the area code received by the code reception
 means, if the code matching judgment means judged that the country code
 and the area code received by the code reception means are not the same as
 the country code and the area code stored in the base area code memory
 means. The time difference information matching judgment means judges
 whether or not the time difference information acquired by the time
 difference information searching means is the same as time difference
 information which has been stored in the time difference information
 memory means. Time difference information stored in the time difference
 information memory means is updated to the time difference information
 acquired by the time difference information searching means by the search,
 if the time difference information matching judgment means judged that the
 time difference information acquired by the time difference information
 searching means is not the same as the time difference information which
 has been stored in the time difference information memory means. The local
 time correction means executes correction of the local time clocked by the
 local clock means based on the time difference information acquired by the
 time difference information searching means and the base time clocked by
 the base clock means, if the time difference information matching judgment
 means judged that the time difference information acquired by the time
 difference information searching means is not the same as the time
 difference information which has been stored in the time difference
 information memory means. And the time display means displays the base
 time clocked by the base clock means and the local time clocked by the
 local clock means.
 In accordance with a second aspect of the present invention, in the first
 aspect, the pager further comprises an informing means. The informing
 means informs the user about the correction of the local time and/or the
 corrected local time when the local time correction means executed the
 correction of the local time clocked by the local clock means.
 In accordance with a third aspect of the present invention, in the first
 aspect, the pager further comprises an area name display means. The area
 name display means displays the names of a country and an area
 corresponding to the country code and the area code received by the code
 reception means, in the case where the code matching judgment means judged
 that the country code and the area code received by the code reception
 means are not the same as the country code and the area code stored in the
 base area code memory means.
 In accordance with a fourth aspect of the present invention, there is
 provided a pager for receiving radio selective calling from a paging
 system, comprising a base area code memory means, a time difference table
 storage means, a base clock means, a local clock means, a code reception
 means, a code matching judgment means, a time difference information
 searching means, a time difference information matching judgment means, a
 time difference information memory means, a local time correction inquiry
 means, a local time correction means, and a time display means. The
 components of the pager other than the local time correction inquiry means
 and the local time correction means operate basically in the same way as
 those of the pager according to the first aspect of the present invention.
 The local time correction inquiry means inquires of the user about whether
 or not the user intends to let the pager correct the local time clocked by
 the local clock means, if the time difference information matching
 judgment means judged that the time difference information acquired by the
 time difference information searching means is not the same as the time
 difference information which has been stored in the time difference
 information memory means. The local time correction means executes
 correction of the local time clocked by the local clock means based on the
 time difference information acquired by the time difference information
 searching means and the base time clocked by the base clock means, if the
 user answered to the local time correction inquiry means that the user
 intends to let the pager correct the local time clocked by the local clock
 means. And the time display means displays the base time clocked by the
 base clock means and the local time clocked by the local clock means.
 In accordance with a fifth aspect of the present invention, in the fourth
 aspect, the pager further comprises an informing means. The informing
 means informs the user about the correction of the local time and/or the
 corrected local time when the local time correction means executed the
 correction of the local time clocked by the local clock means.
 In accordance with a sixth aspect of the present invention, in the fourth
 aspect, the pager further comprises an area name display means. The area
 name display means displays the names of a country and an area
 corresponding to the country code and the area code received by the code
 reception means, in the case where the code matching judgment means judged
 that the country code and the area code received by the code reception
 means are not the same as the country code and the area code stored in the
 base area code memory means.
 In accordance with a seventh aspect of the present invention, there is
 provided a pager for receiving radio selective calling from a paging
 system, comprising a base area code memory means, a time difference table
 storage means, a base clock means, a local clock means, a code reception
 means, a local time information reception means, a code matching judgment
 means, a time difference information searching means, a time difference
 information matching judgment means, a time difference information memory
 means, a first local time correction means, a base time correction means,
 a second local time correction means, and a time display means. The
 components of the pager other than the local time information reception
 means, the first local time correction means, the base time correction
 means and the second local time correction means operate basically in the
 same way as those of the pager according to the first aspect of the
 present invention. The local time information reception means executes
 reception of local time information which is transmitted by the base
 station of the paging system. The first local time correction means
 executes correction of the local time clocked by the local clock means
 based on the time difference information acquired by the time difference
 information searching means and the base time clocked by the base clock
 means, if the time difference information matching judgment means judged
 that the time difference information acquired by the time difference
 information searching means is not the same as the time difference
 information which has been stored in the time difference information
 memory means. The base time correction means executes correction of the
 base time clocked by the base clock means based on the local time
 information, if the code matching judgment means judged that the country
 code and the area code received by the code reception means are the same
 as the country code and the area code stored in the base area code memory
 means and if the local time information reception means received the local
 time information transmitted by the base station of the paging system. The
 second local time correction means executes correction of the local time
 clocked by the local clock means based on the local time information, if
 the time difference information matching judgment means judged that the
 time difference information acquired by the time difference information
 searching means is not the same as the time difference information which
 has been stored in the time difference information memory means and if the
 local time information reception means received the local time information
 transmitted by the base station of the paging system. And the time display
 means displays the base time clocked by the base clock means and the local
 time clocked by the local clock means.
 In accordance with an eighth aspect of the present invention, in the
 seventh aspect, the pager further comprises an informing means. The
 informing means informs the user about the correction of the local time
 and/or the corrected local time when the first local time correction means
 executed the correction of the local time clocked by the local clock
 means.
 In accordance with a ninth aspect of the present invention, in the seventh
 aspect, the pager further comprises an area name display means. The area
 name display means displays the names of a country and an area
 corresponding to the country code and the area code received by the code
 reception means, in the case where the code matching judgment means judged
 that the country code and the area code received by the code reception
 means are not the same as the country code and the area code stored in the
 base area code memory means.
 In accordance with a tenth aspect of the present invention, there is
 provided a time display method for a pager for receiving radio selective
 calling from a paging system. The time display method comprises a base
 area code memory step, a time difference table storage step, a base time
 clocking step, a local time clocking step, a code reception step, a code
 matching judgment step, a time difference information searching step, a
 time difference information matching judgment step, a time difference
 information update step, a local time correction step, and a time display
 step. In the base area code memory step, a country code and an area code
 which indicate the base area of the pager are prestored in a base area
 code memory means of the pager. In the time difference table storage step,
 a table including country codes and area codes of a plurality of countries
 and areas and time difference information of each country/area in
 comparison with a reference time such as the GMT (Greenwich Mean Time) is
 prestored in a time difference table storage means of the pager. In the
 base time clocking step, a base clock means of the pager clocks base time,
 which is the time in the base area of the pager. In the local time
 clocking step, a local clock means of the pager clocks local time, which
 is the time in an area in which the pager is located. In the code
 reception step, a code reception means of the pager receives a country
 code and an area code which are transmitted by a base station of the
 paging system. In the code matching judgment step, a code matching
 judgment means of the pager judges whether or not the country code and the
 area code received in the code reception step are the same as the country
 code and the area code stored in the base area code memory means. In the
 time difference information searching step, a time difference information
 searching means of the pager searches the time difference table storage
 means for a piece of time difference information based on the country code
 and the area code received in the code reception step, if the code
 matching judgment means judged in the code matching judgment step that the
 country code and the area code received in the code reception step are not
 the same as the country code and the area code stored in the base area
 code memory means. In the time difference information matching judgment
 step, a time difference information matching judgment means of the pager
 judges whether or not the time difference information acquired in the time
 difference information searching step is the same as time difference
 information which has been stored in a time difference information memory
 means of the pager. In the time difference information update step, the
 time difference information stored in the time difference information
 memory means is updated to the time difference information acquired in the
 time difference information searching step, if the time difference
 information matching judgment means judged in the time difference
 information matching judgment step that the time difference information
 acquired in the time difference information searching step is not the same
 as the time difference information which has been stored in the time
 difference information memory means. In the local time correction step, a
 local time correction means of the pager executes correction of the local
 time clocked by the local clock means based on the time difference
 information acquired in the time difference information searching step and
 the base time clocked by the base clock means, if the time difference
 information matching judgment means judged in the time difference
 information matching judgment step that the time difference information
 acquired in the time difference information searching step is not the same
 as the time difference information which has been stored in the time
 difference information memory means. And in the time display step, the
 base time clocked by the base clock means and the local time clocked by
 the local clock means are displayed by a time display means of the pager.
 In accordance with an eleventh aspect of the present invention, in the
 tenth aspect, the time display method further comprises a local time
 correction information step. In the local time correction information
 step, an informing means of the pager informs the user about the
 correction of the local time and/or the corrected local time when the
 local time correction means executed the correction of the local time
 clocked by the local clock means in the local time correction step.
 In accordance with a twelfth aspect of the present invention, in the tenth
 aspect, the time display method further comprises an area name display
 step. In the area name display step, an area name display means of the
 pager displays the names of a country and an area corresponding to the
 country code and the area code received in the code reception step, in the
 case where the code matching judgment means judged in the code matching
 judgment step that the country code and the area code received in the code
 reception step are not the same as the country code and the area code
 stored in the base area code memory means.
 In accordance with a thirteenth aspect of the present invention, there is
 provided a time display method for a pager for receiving radio selective
 calling from a paging system. The time display method comprises a base
 area code memory step, a time difference table storage step, a base time
 clocking step, a local time clocking step, a code reception step, a code
 matching judgment step, a time difference information searching step, a
 time difference information matching judgment step, a time difference
 information update step, a local time correction inquiry step, a local
 time correction step, and a time display step. The steps other than the
 local time correction inquiry step and the local time correction step are
 executed basically in the same way as those in the time display method
 according to the tenth aspect of the present invention. In the local time
 correction inquiry step, a local time correction inquiry means of the
 pager inquires of the user about whether or not the user intends to let
 the pager correct the local time clocked by the local clock means, if the
 time difference information matching judgment means judged in the time
 difference information matching judgment step that the time difference
 information acquired in the time difference information searching step is
 not the same as the time difference information which has been stored in
 the time difference information memory means. In the local time correction
 step, a local time correction means of the pager executes correction of
 the local time clocked by the local clock means based on the time
 difference information acquired in the time difference information
 searching step and the base time clocked by the base clock means, if the
 user answered in the local time correction inquiry step that the user
 intends to let the pager correct the local time clocked by the local clock
 means. And in the time display step, the base time clocked by the base
 clock means and the local time clocked by the local clock means are
 displayed by a time display means of the pager.
 In accordance with a fourteenth aspect of the present invention, in the
 thirteenth aspect, the time display method further comprises a local time
 correction information step. In the local time correction information
 step, an informing means of the pager informs the user about the
 correction of the local time and/or the corrected local time when the
 local time correction means executed the correction of the local time
 clocked by the local clock means in the local time correction step.
 In accordance with a fifteenth aspect of the present invention, in the
 thirteenth aspect, the time display method further comprises an area name
 display step. In the area name display step, an area name display means of
 the pager displays the names of a country and an area corresponding to the
 country code and the area code received in the code reception step, in the
 case where the code matching judgment means judged in the code matching
 judgment step that the country code and the area code received in the code
 reception step are not the same as the country code and the area code
 stored in the base area code memory means.
 In accordance with a sixteenth aspect of the present invention, there is
 provided a time display method for a pager for receiving radio selective
 calling from a paging system. The time display method comprises a base
 area code memory step, a time difference table storage step, a base time
 clocking step, a local time clocking step, a code reception step, a local
 time information reception step, a code matching judgment step, a time
 difference information searching step, a time difference information
 matching judgment step, a time difference information update step, a first
 local time correction step, a base time correction step, a second local
 time correction step, and a time display step. The steps other than the
 local time information reception step, the first local time correction
 step, the base time correction step and the second local time correction
 step are executed basically in the same way as those in the time display
 method according to the tenth aspect of the present invention. In the
 local time information reception step, a local time information reception
 means of the pager executes reception of local time information which is
 transmitted by the base station of the paging system. In the first local
 time correction step, a first local time correction means of the pager
 executes correction of the local time clocked by the local clock means
 based on the time difference information acquired in the time difference
 information searching step and the base time clocked by the base clock
 means, if the time difference information matching judgment means judged
 in the time difference information matching judgment step that the time
 difference information acquired in the time difference information
 searching step is not the same as the time difference information which
 has been stored in the time difference information memory means. In the
 base time correction step, a base time correction means of the pager
 executes correction of the base time clocked by the base clock means based
 on the local time information, if the code matching judgment means judged
 in the code matching judgment step that the country code and the area code
 received in the code reception step are the same as the country code and
 the area code stored in the base area code memory means and if the local
 time information reception means received the local time information in
 the local time information reception step. In the second local time
 correction step, a second local time correction means of the pager
 executes correction of the local time clocked by the local clock means
 based on the local time information, if the time difference information
 matching judgment means judged in the time difference information matching
 judgment step that the time difference information acquired in the time
 difference information searching step is not the same as the time
 difference information which has been stored in the time difference
 information memory means and if the local time information reception means
 received the local time information in the local time information
 reception step. And in the time display step, the base time clocked by the
 base clock means and the local time clocked by the local clock means are
 displayed by a time display means of the pager.
 In accordance with a seventeenth aspect of the present invention, in the
 sixteenth aspect, the time display method further comprises a local time
 correction information step. In the local time correction information
 step, an informing means of the pager informs the user about the
 correction of the local time and/or the corrected local time when the
 first local time correction means executed the correction of the local
 time clocked by the local clock means in the local time correction step.
 In accordance with an eighteenth aspect of the present invention, in the
 sixteenth aspect, the time display method further comprises an area name
 display step. In the area name display step, an area name display means of
 the pager displays the names of a country and an area corresponding to the
 country code and the area code received in the code reception step, in the
 case where the code matching judgment means judged in the code matching
 judgment step that the country code and the area code received in the code
 reception step are not the same as the country code and the area code
 stored in the base area code memory means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring now to the drawings, a description will be given in detail of
 preferred embodiments in accordance with the present invention.
 FIG. 1 is a block diagram showing a pager according to a first embodiment
 of the present invention. The pager comprises an antenna 1, a demodulation
 section 2, a synchronization signal detection section 3, a decoding
 section 4, a system information detection section 5, a base area code
 memory section 6, a CPU 7 (Central Processing Unit), a speaker driver
 section 8, a speaker 9, an LCD (Liquid Crystal Display) 10, a base clock
 section 11, a local clock section 12, a time difference table 13, a time
 difference information memory section 14, and an intermittent reception
 control section 15. The components of the pager of FIG. 1 (other than the
 antenna 1, the CPU 7, the speaker 9 and the LCD 10) are realized by, for
 example, one or more microprocessor units which are composed of one or
 more CPUs (Central Processing Units), ROM (Read Only Memory), RAM (Random
 Access Memory), etc. It is also possible to realize the components of the
 pager of FIG. 1 (other than the antenna 1, the speaker 9 and the LCD 10)
 by software and a microprocessor unit for executing the instructions of
 the software.
 The demodulation section 2 is connected to the antenna 1. The
 synchronization signal detection circuit 3 and the decoding circuit 4 are
 connected to the demodulation section 2. The system information detection
 circuit 5 is connected to the decoding circuit 4 and the base area code
 memory section 6. The CPU 7 is connected with the synchronization signal
 detection circuit 3, the decoding circuit 4, the system information
 detection section 5, the base area code memory section 6, the speaker
 driver section 8, the LCD 10, the base clock section 11, the local clock
 section 12, the time difference table 13, the time difference information
 memory section 14 and the intermittent reception control section 15. The
 speaker driving section 8 is connected to the speaker 9 in order to drive
 the speaker 9. The intermittent reception control section 15 is connected
 to the demodulation section 2 for intermittently activating the
 demodulation section 2.
 A base station of a paging system transmits a selective calling signal
 which contains system information, local time information and message
 information to pagers. The system information includes a country code and
 an area code. The local time information indicates local time of the area
 in which the base station is located. Incidentally, the pager of the first
 embodiment utilizes the country code and the area code included in the
 system information, and does not need the local time information in the
 operation which will be described later referring to FIG. 2. The
 demodulation section 2 of the pager receives the selective calling signal
 including the system information, local time information and message
 information via the antenna 1, demodulates the selective calling signal,
 and thereby outputs a demodulated signal. The synchronization signal
 detection section 3 receives the demodulated signal from the demodulation
 section 2 and detects a synchronization signal of each frame of the
 demodulated signal. The decoding section 4 decodes the demodulated signal
 outputted by the demodulation section 2 based on the synchronization
 signal detected by the synchronization signal detection section 3, and
 thereby outputs decoded data to the CPU 7 and the system information
 detection section 5.
 The base area code memory section 6 stores a country code and an area code
 which indicate the base area of the pager of FIG. 1, that is, the country
 and the area in which the pager of FIG. 1 has been distributed. The
 country code and the area code indicating the base area is written in the
 base area code memory section 6 before the pager is distributed to the
 user. The system information detection section 5 detects and extracts a
 country code and an area code from the system information of the decoded
 data outputted by the decoding section 4, compares the country code and
 the area code with those stored in the base area code memory section 6,
 and informs the result of the comparison to the CPU 7. The speaker driving
 section 8 is a unit for driving the speaker 9 according to instructions of
 the CPU 7. The LCD 10 is used for displaying received messages (when a
 message is received), base time which is clocked by the base clock section
 11, local time which is clocked by the local clock section 12, and the
 names of a country and an area which are designated by the country code
 and the area included in the system information. The LCD 10 is also used
 for informing the user about update of time difference information, when
 the pager of FIG. 1 updated the time difference information. The
 intermittent reception control section 15 intermittently turns on power
 supply to the demodulation section 2, and thereby activates the
 demodulation section 2 at predetermined periods.
 The time difference table 13 stores country codes and area codes of a
 plurality of countries and areas, and time differences of each
 country/area in comparison with the GMT (Greenwich Mean Time). The time
 difference information memory section 14 stores the time difference
 information concerning time difference between the base time and the local
 time. The time difference information is updated based on the result of
 search of the time difference table 13 using the country code and the area
 code which have been included in the system information. The time
 difference information memory section 14 includes a time difference update
 pointer. The time difference update pointer indicates whether or not the
 time difference information in the time difference information memory
 section 14 has been updated.
 The base clock section 11 clocks the base time, that is, the time in the
 base area of the pager of FIG. 1. The local clock section 12 holds time
 which is calculated by the CPU 7 based on the time difference information
 which is stored in the time difference information memory section 14 and
 the base time which is clocked by the base clock section 11.
 In the following, the operation of the pager according to the first
 embodiment of the present invention will be described referring to FIG. 1
 and FIG. 2. FIG. 2 is a flow chart showing the operation of the pager of
 the first embodiment. The intermittent reception control section 15
 intermittently turns on power supply to the demodulation section 2 and
 thereby activates the demodulation section 2 at predetermined periods.
 When the demodulation section 2 is under operating conditions, the
 demodulation section 2 receives the selective calling signal transmitted
 by the base station of the paging system via the antenna 1, and
 demodulates the selective calling signal. The selective calling signal
 contains the system information including the country code and the area
 code. The demodulation section 2 outputs the demodulated signal to the
 synchronization signal detection section 3 and the decoding section 4
 (step S101).
 In step S102, the synchronization signal detection section 3 judges whether
 or not synchronization signals in each frame of the demodulated signal can
 be detected. If the synchronization signals are detected in the frames of
 the demodulated signal ("YES" in the step S102), the process proceeds to
 step S103. If the synchronization signals are not detected ("NO" in the
 step S102), the process is returned to the step S101.
 In the step S103, the decoding section 4 decodes the demodulated signal
 outputted by the demodulation section 2 based on the synchronization
 signal detected by the synchronization signal detection section 3 and
 thereby outputs decoded data. The system information detection section 5
 detects and extracts the system information including the country code and
 the area code from the decoded data outputted by the decoding section 4,
 and judges whether or not the country code and the area code extracted
 from the decoded data are the same as those stored in the base area code
 memory section 6. If the country code and the area code are the same as
 those stored in the base area code memory section 6 ("YES" in the step
 S103), the process directly proceeds to step S105. If the country code and
 the area code are not the same as those stored in the base area code
 memory section 6 ("NO" in the step S103), a mismatch flag MFG is set at 1
 (step S104), and the process proceeds to the step S105.
 In the step S105, the CPU 7 judges whether or not a message to the pager
 itself has been received. If the message to the pager has not been
 received ("NO" in the step S105), the process directly proceeds to step
 S107. If the message to the pager has been received ("YES" in the step
 S105), the process proceeds to the next step S106. In the step S106, the
 CPU7 informs the user of reception of the message by making a beep from
 the speaker 9 by activating the speaker driver section 8, displays the
 message on the LCD 10, and stores the message in a reception message
 memory.
 In the step S107, the CPU 7 checks whether or not the mismatch flag MFG has
 been set at 1. If the mismatch flag MFG has not been set at 1 ("NO" in the
 step S107), the CPU 7 displays the base time (which is clocked by the base
 clock section 11) only on the LCD 10 (step S108), and the process proceeds
 to step S109. Incidentally, if both the base time and the local time have
 been displayed on the LCD 10 at the point of the step S108, the CPU 7
 stops the display of the local time. If the mismatch flag MFG has been set
 at 1 ("YES" in the step S107), the CPU 7 acquires time difference
 information from the time difference table 13 by searching the time
 difference table 13 using the country code and the area code outputted by
 the system information detection section 5 (step S110). In the next step
 S111, the CPU 7 judges whether or not the time difference information
 acquired in the step S110 is the same as the time difference information
 which has been stored in the time difference information memory section
 14. If the time difference information is the same ("YES" in the step
 S111), the process proceeds to step S116.
 If the time difference information is not the same ("NO" in the step S111),
 process from step 112 to step S115 is executed. In the step S112, the CPU
 7 stores the time difference information acquired in the step S110 in the
 time difference information memory section 14 (i.e. updates the time
 difference information). In the step S113, the CPU 7 sets the time
 difference update pointer at 1. In the step S114, the CPU 7 confirms that
 the time difference update pointer in the time difference information
 memory section 14 has been set at 1, and informs the user that the time
 difference information has just been updated, by making a beep from the
 speaker 9. At the same time, the CPU 7 displays the names of the country
 and the area which are designated by the received country code and the
 received area code on the LCD 10. In the step S115, the CPU 7 corrects the
 local time which is clocked by the local clock section 12. The local time
 correction of the step S115 is executed in the case where the received
 country code and the received area code (which have been detected by the
 system information detection section 5) are not the same as the base
 country code and the base area code which are stored in the base area code
 memory section 6 (the mismatch flag MFG=1) and the time difference update
 pointer in the time difference information memory section 14 has been set
 at 1. In the local time correction of the step S115, the CPU 7 calculates
 local time by referring to the base time of the base clock section 11 and
 the time difference information stored in the time difference information
 memory section 14, and gives the calculated local time to the local clock
 section 12.
 In the step S116, the CPU 7 displays the local time and the base time on
 the LCD 10. At the same time, the CPU 7 displays the names of the country
 and the area which are designated by the country code and the area which
 have been detected by the system information detection section 5, on the
 LCD 10.
 In the next step S109, the CPU 7 executes initialization. In the
 initialization, the mismatch flag MFG and the time difference update
 pointer in the time difference information memory section 14 are
 initialized (reset to 0).
 As described above, in the pager according to the first embodiment of the
 present invention, when the pager is located in an area outside the base
 area of the pager, the time difference information of the area outside the
 base area (where time difference from the base time occurs) is acquired
 immediately and correctly based on the country code and the area code
 which are contained in the system information of the selective calling
 signal transmitted by a base station of the paging system, and the local
 time of the area outside the base area is displayed on the LCD 10 based on
 the acquired time difference information, along with displaying the base
 time of the base area of the pager on the LCD 10.
 In the case where the time difference information acquired based on the
 country code and the area code in the system information is different from
 time difference information which has been stored in the time difference
 information memory section 14 (i.e. in the case where the pager moved to
 an area of different time difference), the time difference information in
 the time difference information memory section 14 is updated and the user
 is informed about the update of the time difference information by the
 beep from the speaker 9 and the display on the LCD 10, and the local time
 clocked by the local clock section 12 is corrected based on the updated
 time difference information and the base time clocked by the base clock
 section 11. On the LCD 10, the names of the country and the area in which
 the pager is located can also be displayed.
 In the following a pager according to a second embodiment of the present
 invention will be described referring to FIG. 1 and FIG. 3. FIG. 3 is a
 flow chart showing the operation of the pager of the second embodiment.
 The pager of the second embodiment has basically the same composition as
 the pager of the first embodiment as shown in FIG. 1, however, the
 operation is a little different. Incidentally, in FIG. 3, the same step
 number as that used in FIG. 2 is used when the operation in the step is
 the same as that in FIG. 2.
 The pager of second embodiment is realized and is effective in the case
 where the local time information is contained in the selective calling
 signal transmitted by the base stations of the paging system. The
 difference of the second embodiment from the first embodiment is that the
 pager of the second embodiment further employs a local time information
 acquisition flag LTFG, and the flow chart of FIG. 3 further includes steps
 for reflecting acquired (received) local time information in either the
 base time clocked by the base clock section 11 or the local time clocked
 by the local clock section 12. Concretely, the flow chart of FIG. 3
 further includes steps S201 and S202 between the steps S104 and S105 of
 FIG. 2, and steps S203 and S204 between the steps S107 and S108 of FIG. 2,
 and steps S205 and S206 between the steps S115 and S116 of FIG. 2.
 The operation of the pager in the steps S101 through S104 is the same as
 that in the first embodiment, and thus explanation thereof is omitted for
 brevity. In the step S201, the CPU 7 judges whether or not the local time
 information has been detected in the decoded data outputted by the
 decoding section 4. If the local time information has not been detected
 ("NO" in the step S201), the process directly proceeds to the step S105.
 If the local time information has been detected ("YES" in the step S201),
 the CPU 7 sets the local time information acquisition flag LTFG at 1 (step
 S202), and thereafter proceeds to the step S105.
 The operation of the pager in the steps S105 through S107 is the same as
 that in the first embodiment, and thus explanation thereof is omitted. If
 the mismatch flag MFG has not been set at 1 ("NO" in the step S107), the
 process proceeds to the step S203 and the CPU 7 judges whether or not the
 local time information acquisition flag LTFG has been set at 1. If the
 local time information acquisition flag LTFG has not been set at 1 ("NO"
 in the step S203), the CPU 7 displays the base time on the LCD 10 (step
 S108) and proceeds to the step S109. If the local time information
 acquisition flag LTFG has been set at 1 ("YES" in the step S203), the CPU
 7 corrects the base time clocked by the base clock section 11 based on the
 local time information (which indicates the "base time" since the pager is
 located in the base area) decoded by the decoding section 4 (step S204),
 thereafter displays the base time on the LCD 10 (step S108), and proceeds
 to the step S109.
 If the mismatch flag MFG has been set at 1 ("YES" in the step S107), the
 process proceeds to the step S110. The operation of the pager in the steps
 S110 through S115 is the same as that in the first embodiment, and thus
 explanation thereof is omitted. In the step S205 after the step S115, the
 CPU 7 judges whether or not the local time information acquisition flag
 LTFG has been set at 1. If the local time information acquisition flag
 LTFG has not been set at 1 ("NO" in the step S205), the process directly
 proceeds to the step S116 and the CPU 7 displays the local time and the
 base time (and the names of the country and the area) on the LCD 10. If
 the local time information acquisition flag LTFG has been set at 1 ("YES"
 in the step S205), the CPU 7 corrects the local time clocked by the local
 clock section 12 based on the local time information (which indicates the
 "local time" since the pager is located outside the base area) decoded by
 the decoding section 4 (step S206), thereafter displays the local time and
 the base time (and the names of the country and the area) on the LCD 10
 (step S116), and proceeds to the step S109. In the step S109, the CPU 7
 executes initialization. In the initialization, the mismatch flag MFG, the
 time difference update pointer in the time difference information memory
 section 14, and the local time information acquisition flag LTFG are
 initialized (reset to 0).
 As described above, by the pager according to the second embodiment of the
 present invention, in addition to the effects of the first embodiment, the
 base time which has been adjusted based on the local time information can
 be displayed on the LCD 10 in the case where the pager received the local
 time information transmitted by a base station of the paging system in the
 base area, and the local time which has been adjusted based on the local
 time information can be displayed on the LCD 10 in the case where the
 pager received the local time information transmitted by a base station of
 the paging system outside the base area.
 In the following a pager according to a third embodiment of the present
 invention will be described referring to FIG. 1 and FIG. 4. FIG. 4 is a
 flow chart showing the operation of the pager of the third embodiment. The
 pager of the third embodiment has basically the same composition as the
 pager of the first embodiment as shown in FIG. 1, however, the operation
 is a little different. Incidentally, in FIG. 4, the same step number as
 that used in FIG. 2 is used when the operation in the step is the same as
 that in FIG. 2.
 The pager of third embodiment inquires of the user about whether or not the
 user intends to let the pager correct (update) the local time clocked by
 the local clock section 12 and display the corrected local time on the LCD
 10. Therefore, the flow chart of FIG. 4 further includes steps S301 and
 S302 between the steps S114 and S115 of FIG. 2.
 The operation of the pager in the steps S101 through S114 is the same as
 that in the first embodiment, and thus explanation thereof is omitted for
 brevity. In the step S301 after the step S114, the CPU 7 displays "UPDATE
 LOCAL TIME? (YES or NO)" on the LCD 10 in order to ask the user whether or
 not the user intends to update and display the local time. In the next
 step S302, the CPU 7 executes switch status judgment. In the switch status
 judgment, the CPU 7 waits for key input by the user and judges whether the
 user pushed a key corresponding to "YES" or a key corresponding to "NO".
 If the user answered "NO" in the step S302, the CPU 7 displays the base
 time only on the LCD 10 (step S108) and proceeds to the step S109. If the
 user answered "YES" in the step S302, the CPU 7 corrects the local time
 clocked by the local clock section 12 based on the base time of the base
 clock section 11 and the time difference information stored in the time
 difference information memory section 14 (step S115), thereafter displays
 the local time and the base time (and the names of the country and the
 area) on the LCD 10 (step S116), and proceeds to the step S109. In the
 step S109, the CPU 7 executes initialization. In the initialization, the
 mismatch flag MFG and the time difference update pointer in the time
 difference information memory section 14 are initialized (reset to 0).
 As described above, by the pager according to the third embodiment of the
 present invention, in addition to the effects of the first embodiment, the
 user of the pager located outside the base area can make a choice between
 "correcting the local time based on the time difference information and
 displaying the local time and the base time on the LCD 10" and "displaying
 the base time only on the LCD 10 without correcting the local time".
 As set forth hereinabove, in the pager and the time display method for a
 pager according to the present invention, when the pager is carried to an
 area outside the base area of the pager, time difference information of
 the area outside the base area (where time difference from the base time
 occurs) is acquired immediately and correctly based on the country code
 and the area code which are contained in the system information of the
 selective calling signal transmitted by a base station of the paging
 system, and thereby the time of day clocked by the local clock section 12
 is automatically corrected to the local time in the area in which the
 pager is located, and the corrected local time is displayed to the user,
 along with displaying the base time clocked by the base clock section 11
 which indicates the time of day in the base area of the pager. Therefore,
 when the pager is located outside the base area of the pager, the user can
 see the base time in the base area of the pager, along with seeing the
 corrected local time in the area outside the base area.
 While the present invention has been described with reference to the
 particular illustrative embodiments, it is not to be restricted by those
 embodiments but only by the appended claims. It is to be appreciated that
 those skilled in the art can change or modify the embodiments without
 departing from the scope and spirit of the present invention.