U.S. patent application number 11/372421 was filed with the patent office on 2006-07-06 for portable information apparatus having communications tools, a control system for controlling such portable information apparatus, and an apparatus having such control system.
This patent application is currently assigned to ROHM CO., LTD.. Invention is credited to Takashi Naiki.
Application Number | 20060148422 11/372421 |
Document ID | / |
Family ID | 26595692 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060148422 |
Kind Code |
A1 |
Naiki; Takashi |
July 6, 2006 |
Portable information apparatus having communications tools, a
control system for controlling such portable information apparatus,
and an apparatus having such control system
Abstract
A portable information apparatus 20 having communications tools
is provided with a switch 22a for instructing
enablement/disenablement of transmission functions of the wireless
transmission/reception section 21 of the portable information
apparatus 20. The portable information apparatus 20, upon receipt
of a transmission prohibition signal from an prohibition signal
transmitter 31 installed in a public facility 30, determines
whether the transmission functions must be disenabled and
automatically controls enablement/disenablement of the transmission
functions. The portable information apparatus is thus automatically
turned off even when the carrier of the apparatus has forgotten to
turn off the transmission functions, thereby allowing the carrier
to perform necessary operations not involving transmission of
electromagnetic waves without causing a nuisance to others.
Inventors: |
Naiki; Takashi; (Ukyo-ku,
JP) |
Correspondence
Address: |
HOGAN & HARTSON L.L.P.
500 S. GRAND AVENUE
SUITE 1900
LOS ANGELES
CA
90071-2611
US
|
Assignee: |
ROHM CO., LTD.
|
Family ID: |
26595692 |
Appl. No.: |
11/372421 |
Filed: |
March 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09900701 |
Jul 5, 2001 |
7039426 |
|
|
11372421 |
Mar 9, 2006 |
|
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Current U.S.
Class: |
455/78 |
Current CPC
Class: |
H04M 1/72463 20210101;
H04M 1/67 20130101; H04W 48/04 20130101 |
Class at
Publication: |
455/078 |
International
Class: |
H04B 1/44 20060101
H04B001/44 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 10, 2000 |
JP |
2000-208159 |
Jun 21, 2001 |
JP |
2001-188269 |
Claims
1-12. (canceled)
13. A portable information apparatus having communications tools,
said portable information apparatus including: a wireless
transmission/reception section for transmitting to and receiving
from an external wireless transmitter/receiver electromagnetic
signals; said portable information apparatus further comprising
reception means, within or outside said wireless
transmission/reception section, for receiving a communication
prohibition signal and/or a communication permission signal
transmitted by the electromagnetic waves from an external facility,
and for enabling/disenabling said transmission functions of said
wireless transmission/reception section upon receipt of said
communication prohibition signal and/or said communication
permission signal, wherein said communication prohibition signal
and/or said communication permission signal are/is weaker than the
electromagnetic waves transmitted from said wireless
transmission/reception section of said portable information
apparatus.
14. The portable information apparatus having communications tools
according to claim 13, wherein said wireless transmission/reception
section is adapted to serve as a dedicated wireless receiver when
said transmission functions of said wireless transmission/reception
section are disenabled.
15. The portable information apparatus having communications tools
according to claim 13, further comprising: a data section for
storing data regarding the portable information apparatus; a
discrimination section, adapted to receive the results of the
reception from the reception means and receive data from the data
section, for setting the transmission function of the wireless
transmission/reception section enabled or disenabled, based on the
results received from the reception means and the data received
from the data section.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a portable information apparatus
having communications tools, e.g. a cellular phone and a personal
handyphone system (PHS), and to a control system for controlling
such portable information apparatus, and further to an apparatus
equipped with a controller for controlling such portable
information apparatus.
BACKGROUND OF THE INVENTION
[0002] Portable telephone systems such as cellular phones have
extensively diffused among people because of the convenience of
such system that the carrier of the system can be paged wherever he
is, and he can call up his partner from anywhere. Particularly,
because of recent improvements of cellular phones and
infrastructures of cellular phone systems, cellular phones have
functionally evolved beyond mere telephonic devices and have become
versatile portable information apparatuses having information
processing functions to deal with e-mail and retrieve
information.
[0003] These portable information apparatuses e.g. cellular phones
are configured to transmit electromagnetic waves not only for
communication with a relay station (hereinafter referred to as base
station) to talk with partners but also for period registration of
their current locations at the base station so that the apparatuses
can receive telephone calls and e-mail.
[0004] As a result of dissemination of such portable information
apparatuses, strong electromagnetic waves are emitted everywhere
for communications, thereby posing serious problems to devices such
as cardiac pace-makers that can fail under strong ambient
electromagnetic waves.
[0005] A countermeasure for such situations is to have the portable
information apparatuses turned off, as in actuality requested to do
so in public facilities. However, the portable information
apparatuses e.g. cellular phones have versatile information
processing functions to deal with e-mail and to retrieve
information. They are suited to read information received and/or
prepare e-mail while waiting for receipt of a message.
Consequently, it is difficult to resort to the sense of morality of
the carriers to turn off the portable information apparatuses.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the invention to provide:
[0007] a portable information apparatus such as cellular phones
having communications tools capable of stopping transmission
functions thereof while maintaining information processing
functions thereof;
[0008] a control system for controlling the portable information
apparatus, and
[0009] an apparatus equipped with a controller for controlling the
portable information apparatus.
[0010] There is provided, in accordance with one aspect of the
present invention, a portable information apparatus having
communications tools, said portable information apparatus
including:
[0011] a wireless transmission/reception section for transmitting
to and receiving from an external wireless transmitter/receiver
electromagnetic signals;
[0012] an operation section for performing various operations;
[0013] a display section for displaying status of the operations
made by said operation section, and status and the results of
transmission/reception operations made by said wireless
transmission/reception section; and
[0014] a control section connected with said wireless
transmission/reception section, operation section, and display
section, for controlling overall actions of said portable
information apparatus, wherein
[0015] said operation section has selection means for selectively
enabling/disenabling said transmission functions of the wireless
transmission/reception section.
[0016] By providing the selection means in the form of a switch for
example for selectively enabling/disenabling the transmission
functions of the wireless transmission/reception section in
addition to a power supply switch for the entire apparatus, it is
possible for the carrier of the apparatus to turn off only the
transmission functions. Thus, it is possible for the carrier to
perform certain operations e.g. viewing received information and
preparing for e-mail in a public facilities for example where
transmission of electromagnetic waves is prohibited, thereby
carrying out desired operations without causing a nuisance to the
public.
[0017] There is provided, in accordance with another aspect of the
present invention, a portable information apparatus having
communications tools, said portable information apparatus
including:
[0018] a wireless transmission/reception section for transmitting
to and receiving from an external wireless transmitter/receiver
electromagnetic signals;
[0019] an operation section for performing various operations;
[0020] a display section for displaying status of the operations
made by said operation section, and status and the results of
transmission/reception operations made by said wireless
transmission/reception section; and
[0021] a control section connected with said wireless
transmission/reception section, operation section, and display
section, for controlling overall actions of said portable
information apparatus,
[0022] said portable information apparatus further comprising
[0023] reception means, within or outside said wireless
transmission/reception section, for receiving a communication
prohibition signal and/or a communication permission signal
transmitted from an external facility, and for enabling/disenabling
said transmission functions of said wireless transmission/reception
section upon receipt of the communication prohibition signal and/or
the communication permission signal.
[0024] In this portable information apparatus having communications
tools, the transmission functions of the wireless
transmission/reception section may be automatically
enabled/disenabled depending on which of the communication
prohibition signal and/or the communication permission signal
are/is received from the external facility. Accordingly, the
transmission functions of the portable information apparatus may be
automatically turned off if the carrier of the portable information
apparatus has forgotten to do so. Thus, operations that do not
require transmission of electromagnetic waves can be performed
without causing a nuisance to others in a public facility.
[0025] The portable information apparatus having such
communications tools may be adapted to serve as a dedicated
receiver when the transmission functions are disenabled.
[0026] Thus, the portable information apparatus having such
communication functions can be used to receive urgent information
even when the transmission functions of the wireless
transmission/reception section are disenabled.
[0027] The communication prohibition signal and/or the
communication permission signal are/is weaker in intensity than the
electromagnetic waves transmitted from the wireless
transmission/reception section of the portable information
apparatus.
[0028] Since the communication prohibition signal and/or the
communication permission signal are/is weaker than the
electromagnetic wave transmitted from the wireless
transmission/reception section of the portable information
apparatus, the communication prohibition signal and/or the
communication permission signal little affect(s) the apparatuses
that can easily go wrong under strong ambient electromagnetic
waves.
[0029] The portable information apparatus having commuinications
tools may comprise:
[0030] a data section for storing data regarding the portable
information apparatus;
[0031] a discrimination section, adapted to receive the results of
the reception from the reception means and receive data from the
data section, for setting the transmission function of the wireless
transmission/reception section enabled or disenabled, based on the
results received from the reception means and the data received
from the data section.
[0032] The portable information apparatus having the communications
tools may effect appropriate control of the communications tools by
determining whether the transmission functions of the wireless
transmission/reception section must be enabled/disenabled based on
the limitations contained in the communication prohibition signal
and/or the communication permission signal received from the
external facility and the data regarding the portable information
apparatus.
[0033] There is provided, in accordance with a further aspect of
the present invention, a control system for controlling portable
information apparatuses having communications tools, the control
system having a transmitter for transmitting a communication
prohibition signal and/or a communication permission signal to the
portable information apparatuses, said transmitter installed at a
location where transmissions of electromagnetic waves from the
portable information apparatuses are prohibited.
[0034] The transmission functions of portable information
apparatuses, when brought to a congested location such as a train,
a bus, and a station, or in an educational facility where
transmission of electromagnetic waves is prohibited, are
automatically stopped by a communication prohibition signal and/or
the communication permission signal transmitted from the control
system installed at the site, thereby not influencing other people
with electromagnetic waves. Even then the carrier of a portable
information apparatus can still perform any processes other than
transmission by means of the portable information apparatus.
[0035] In the control system for controlling portable information
apparatuses having communications tools, the communication
prohibition signal and/or the communication permission signal
are/is weaker than electromagnetic waves transmitted from the
wireless transmission/reception section of the portable information
apparatus.
[0036] In this control system, the communication prohibition signal
and/or the communication permission signal are/is much weaker than
the electromagnetic waves transmitted from the wireless
transmission/reception sections of the portable information
apparatuses that they are less likely to affect other apparatuses
that are easily influenced by strong ambient electromagnetic
waves.
[0037] In the control system, the transmitter is operated under
predetermined conditions.
[0038] For example, in operation, the transmitter is controlled
under predetermined conditions specified by various sensors, a
clock, and a calendar, in accordance with the day and hours and the
degree of congestion of the site.
[0039] The control system may comprise a multiplicity of such
transmitters as described above.
[0040] Such multiple transmitters can cover a wide area that cannot
be covered by a single transmitter.
[0041] There is provided, in accordance with a still further aspect
of the present invention, an apparatus equipped with a controller
for controlling portable information apparatuses having
communications tools, the apparatus comprising a transmitter for
transmitting a communication prohibition signal and/or a
communication permission signal to the portable information
apparatuses, wherein the transmitter is installed on an
electromagnetically susceptible apparatus that can be influenced by
electromagnetic waves transmitted from the portable information
apparatuses.
[0042] The apparatus transmits the communication prohibition signal
and/or the communication permission signal from the transmitter,
which is installed on the electromagnetically susceptible apparatus
such as medical device e.g. cardiac pace-maker and airplane that
can be influenced by electromagnetic waves transmitted from the
portable information apparatuses. Thus, the transmission functions
of portable information apparatuses approaching medical appliances
or on board the airplane having such transmitters are automatically
turned off not to influence others. However, the carriers of the
portable information apparatuses can still perform other operations
that do not involve transmission of electromagnetic waves.
[0043] The communication prohibition signal and/or the
communication permission signal are/is so weak that they do not
influence the electromagnetically susceptible apparatus.
[0044] Thus the apparatus equipped with the controller can prohibit
ambient portable information apparatuses to transmit
electromagnetic waves by transmitting the weak communication
prohibition signal and/or the weak communication permission signal
without affecting the apparatus itself.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] FIG. 1 is a block diagram of a first embodiment of the
invention, in the form of a portable information apparatus having
communications tools.
[0046] FIG. 2 is a block diagram of a second embodiment of the
invention, in the form of a portable information apparatus having
communications tools and a control system for controlling the
apparatus having the communications tools.
[0047] FIG. 3 shows a third embodiment of the invention, in the
form of a control system for controlling a portable information
apparatus having communications tools.
[0048] FIG. 4 shows a fourth embodiment of the invention, in the
form of an apparatus equipped with a controller for controlling a
portable information apparatus having communications tools.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0049] The inventive portable information apparatus having
communications tools, a control system for controlling the portable
apparatus, and an apparatus equipped with a controller for
controlling the portable information apparatus will now be
described in detail by way of example with reference to the
accompanying drawings.
[0050] Referring now to FIG. 1, there is shown in block diagram a
first embodiment of the invention in the form of a portable
information apparatus having communications tools, like a cellular
phone. As shown in FIG. 1, a cellular phone 10 comprises:
[0051] a wireless transmission/reception section 11 for
transmitting/receiving electromagnetic signals for communication
with an external transmission/reception apparatus such as a base
station;
[0052] an operation section 12 for performing various
operations;
[0053] a display section 13 for displaying operational status of an
operation made by the operation section 12 and the status and the
results of transmission/reception made by the wireless
transmission/reception section 11; and
[0054] a control section 14 having a CPU and a memory and connected
with the wireless transmission/reception section 11, the operation
section 12, and with the display section 13, for controlling
overall actions of the cellular phone. The operation section 12 is
provided, along with an overall power supply switch, with a
transmission prohibition button 12a for selectively enabling or
disenabling the transmission functions of the wireless
transmission/reception section 11.
[0055] By pressing the transmission prohibition button 12a of the
operation section 12, the control section 14 is activated to detect
operation of the transmission prohibition button 12a and transmit a
transmission prohibition signal 11a to the wireless
transmission/reception section 11 to disenable the transmission
section of the wireless transmission/reception section 11. At the
same time, the control section 14 sends a display signal 13a
indicative of the prohibition of transmission to the display
section 13. In order to nullify the prohibition of transmission by
the wireless transmission/reception section 11, the transmission
prohibition button 12a is pressed again or a prohibition cancel
button is pressed.
[0056] Thus, according to the invention, only transmission
functions of the wireless transmission/reception section 11 can be
disenabled in proximity to electromagnetically susceptible
apparatuses such as a cardiac pace-maker which can undergo
malfunctions under strong ambient electromagnetic waves, in
response to an announcement for example requesting for stopping
transmission of electromagnetic waves.
[0057] However, it is possible to perform certain operations, e.g.
viewing received information and preparing e-mail information,
which do not require transmission of electromagnetic waves, since
the cellular phone is then still turned on.
[0058] Besides, the portable information apparatus 10 having
communications tools can be used as a dedicated portable
information reception apparatus utilizing the receiving functions
of the wireless transmission/reception section 11 when the
transmission is prohibited, since only the transmission functions
of the wireless transmission/reception section 11 are
disenabled.
[0059] In this case, the cellular phone may be configured to
automatically inform the base station, at the time when the
transmission functions of the wireless transmission/reception
section 11 are disenabled, of the fact that the cellular phone will
be operating only as a dedicated receiver. Since this notification
must be made by transmitting an electromagnetic wave, the
notification is preferably done when the transmission has little
influence to others, i.e. before the carrier enters public
facilities for instance.
[0060] When it is needed to call up the portable information
apparatus 10 that has stopped its transmission functions, the call
can be made efficiently from the base station which the
notification was given or from any other base station in the area
including that original base station. Such call can be made in a
manner similar to a call in a pocket-bell system (pager
system).
[0061] In response to the call, the portable information apparatus
will receive message data, store it in the memory, and/or generate
vibration or display the message to inform the carrier of the
reception.
[0062] In this way, it is possible to receive urgent information
even when the transmission functions of the wireless
transmission/reception section 11 has been stopped.
[0063] The feature of the portable information apparatus having
communications tools that it can be used as a dedicated receiver
can be applied to other embodiments of the invention.
[0064] Referring to FIG. 2, there is shown in block diagram a
second embodiment of a portable information apparatus having
communications tools, such as a cellular phone, along with a
control system for controlling the apparatus.
[0065] As seen in FIG. 2, a cellular phone 20 comprises:
[0066] a wireless transmission/reception section 21 for
transmitting/receiving electromagnetic signals for communication
with an external wireless transmission/reception apparatus;
[0067] an operation section 22 for performing various
operations;
[0068] a display section 23 for displaying status of operations
made by the operation section 22, and status and the results of
transmission/reception operations made by the wireless
transmission/reception section 21; and
[0069] a control section 24 having a CPU and a memory and connected
with the wireless transmission/reception section 21, the operation
section 22, and the display section 23, for controlling overall
actions of the cellular phone. In addition to a power supply switch
for the entire cellular phone, the operation section 22 is further
provided with a transmission prohibition button 22a for selectively
enabling or disenabling the transmission functions of the wireless
transmission/reception section 21. The transmission prohibition
button 22a functions in the same way as the transmission
prohibition button 12a of FIG. 1.
[0070] The cellular phone 20 is further provided with a reception
section 25 for receiving an externally generated communication
prohibition signal and/or a communication permission signal which
determines whether the transmission functions of the wireless
transmission/reception section 21 must be enabled or disenabled.
The communication prohibition signal and/or the communication
permission signal transmitted to the cellular phone 20 are/is
weaker than the electromagnetic wave transmitted from the cellular
phone 20.
[0071] The cellular phone 20 is provided, along with the reception
section 25, with a data section 27 for holding data concerning the
cellular phone 20; and
[0072] a discrimination section 26, adapted to receive the result
of the reception by the reception section 25 and receive the data
from the data section 27, for setting the transmission functions of
the wireless transmission/reception section 21 enabled or
disenabled, in accordance with the result of discrimination
operation made by the discrimination section 26. Incidentally, the
carrier of the portable information apparatus may carry out
necessary operations not involving transmission of electromagnetic
waves from the portable information apparatus, even when the
transmission functions thereof has been disenabled.
[0073] The communication prohibition signal and/or the
communication permission signal for determining
enablement/disenablement of the transmission functions of the
cellular phone 20, are/is transmitted from a prohibition signal
transmitter 31. The prohibition signal transmitter 31 is installed
in a public area 30 such as train, bus, railway station, and
hospital where transmission of electromagnetic waves from portable
information apparatus like cellular phones is prohibited.
[0074] Since the electromagnetic wave from a prohibition signal
transmitter 31 is weak enough (e.g. weak FM waves) not to cause
malfunctions of electromagnetically susceptible apparatuses, the
wave is necessarily weaker than the waves transmitted from cellular
phones 20.
[0075] As a carrier of the cellular phone 20 enters an electric
train for example, the reception section 25 of the cellular phone
20 receives the communication prohibition signal and sends to the
discrimination section 26 information indicative of the fact that
the cellular phone 20 is receiving the signal and restrictive
information contained in the signal if any.
[0076] Upon receipt of the signal from the reception section 25 and
the data from the data section 27, the discrimination section 26
sends a signal to the control section 24 to determine whether the
transmission functions of the wireless transmission/reception
section 21 must be enabled or disenabled.
[0077] For instance, if the communication prohibition signal from
the prohibition signal transmitter 31 includes prohibition of
transmission for a predetermined period (e.g. from 6:30 a.m. to
20:00 p.m.) and permission of PHSs but not cellular phones, the
discrimination section 26 determines enablement/disenablement of
the wireless transmission/reception section 21 based on the data
from the data section 27, that is, clock data and classification
data classifying information apparatuses.
[0078] Incidentally, the cellular phone 20 may be adapted to resume
the operation of the wireless transmission/reception section 21
when no communication prohibition signal is received or when the
cellular phone receives a communication permission signal after it
has received a communication prohibition signal.
[0079] Although it is shown in FIG. 2 that the reception section
25, the discrimination section 26, the data section 27 are provided
separately, the reception section 25 may be substituted for the
wireless transmission/reception section 21, and the discrimination
section 26 and the data section 27 may be integrated in the control
section 24. In that case, the prohibition signal transmitter 31 is
adapted to transmit electromagnetic waves in a multiplicity of
different modes so that the waves can be received by different
types of cellular phones.
[0080] In the portable information apparatus having communications
tools in the form of cellular phones 20, the transmission functions
of the wireless transmission/reception section 21 are automatically
disenabled or enabled in accordance with whether the reception
section 25 has received a communication prohibition signal or a
communication permission signal from an external station. Thus, the
transmission functions of the portable information apparatus will
be automatically turned off or on if the carrier has forgotten to
do so.
[0081] Since the communication prohibition signal and/or the
communication permission signal are/is transmitted from a
transmitter installed in a congested place such as a train, a bus,
and a train station, or an educational facility where transmission
of waves from cellular phones 20 should be prohibited, the
communications tools of portable information apparatuses carried
into such places are automatically stopped without badly affecting
others.
[0082] Referring to FIG. 3, there is shown a structure of a third
embodiment of the invention, in the form of a control system for
controlling portable information apparatuses having communications
tools.
[0083] A prohibition signal transmitter 41 shown in FIG. 3 is
installed in a public place e.g. a train station for transmitting a
communication prohibition signal and/or a communication permission
signal to prohibit and/or permit operation of transmission
functions of cellular phones. The electromagnetic wave transmitted
from the prohibition signal transmitter 41 is weak enough (e.g.
weak FM waves) not to cause malfunctions of electromagnetically
susceptible apparatuses, so that the waves are necessarily weaker
than the waves transmitted from cellular phones.
[0084] The prohibition signal transmitter 41 may be coupled with
various sensors and data means which operate under specified
conditions. For example, the prohibition signal transmitter 41 may
be provided with an infrared sensor 42 for sensing a human being so
as to enable the prohibition signal transmitter 41 only when the
site is congested, or a clock-calendar section 43 to cause the
prohibition signal transmitter 41 to operate during only specified
hours or on specified days, as shown in FIG. 3. The prohibition
signal transmitter 41 may be also provided with an operation
section 44 controlled by an administrator.
[0085] In a spacious place, additional prohibition signal
transmitters 51 may be installed to cover areas which cannot be
covered by individual prohibition signal transmitters. With this
transmitter 51, it is possible to control enablement/disenablement
of the transmission functions of the cellular phones in a spacious
place. It is noted that an infrared sensor 52, a clock-calendar
section 53, and an operation section 54 operate in just the same
ways as the aforementioned infrared sensor 42, clock-calendar 43,
and operation section 44.
[0086] In cases where a spacious place is covered with a
multiplicity of prohibition signal transmitters 41 and 51, these
prohibition signal transmitters 41 and 51 may be coupled with each
other by a common signal line 60, and with a central control
section 61. Thus, these prohibition signal transmitters may operate
in collaboration with each other and may be controlled by an
instruction issued from the central control section 61. Further,
the system may be simplified in structure by controlling all the
infrared sensors 42 and 52, clock-calendar sections 43 and 53,
operation section 44 and 54 by the central control section 61.
[0087] In this case, enablement/disenablement of the transmission
functions of the cellular phones may be controlled alike in a
spacious place such as a train station and a park.
[0088] Referring to FIG. 4, there is shown a fourth embodiment of
the invention in the form of an apparatus equipped with a
controller for controlling the portable information apparatuses
having communications tools.
[0089] A prohibition signal transmitter 71 of FIG. 4 is installed
on an apparatus 70 such as a medical apparatus (e.g. a cardiac
pace-maker) and an airplane which is susceptible to electromagnetic
waves from portable information apparatuses. In such instances, the
communication prohibition signal and/or the communication
permission signal transmitted from the prohibition signal
transmitter 71 are/is weak enough not to influence the operations
of the apparatus 70 itself, and are/is influential only in a
limited area.
[0090] Thus, the communication prohibition signal and/or the
communication permission signal are/is transmitted from the
electromagnetically susceptible apparatus 70 itself, so that
transmission functions of the portable information apparatuses
carried by a person and approaching or getting on board the
apparatus 70 are automatically disenabled. Thus, the apparatus 70
may prohibit ambient portable information apparatuses from
transmitting electromagnetic waves without influencing the
apparatus 70 itself.
[0091] In the examples shown in FIGS. 2 through 4, the
communication prohibition signal and the communication permission
signal provided from the prohibition signal transmitters 31, 41,
51, and 71 are electromagnetic waves. However, the range covered by
the communication prohibition signal and/or the communication
permission signal is so small compared with the distance between
the base station and the cellular phones that the electromagnetic
waves may be replaced by ultrasonic waves or magnetic fields.
* * * * *