Wireless communication system

This invention relates to a wireless communication system, which comprises plural wireless communication units having different communication protocols, and in which a proper wireless communication unit is automatically selected from the plural wireless communication units in accordance with the operation states of the plural wireless communication units to make communication possible. Thereby, troublesome operation is not required, an optimum wireless communication method can be automatically selected, and communication cost can be reduced. In the wireless communication system of the present invention, when mobile stations are registered in a fixed station, preferential orders of the mobile stations are stored, and calling/call-reception and communication processings are controlled according to the preferential orders.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a wireless communication system for performing 
communication by a wireless method, and more particularly, to a wireless 
communication system for performing wireless communication with a fixed 
station connected to a communication network or directly with an exchange. 
2. Description of the Prior Art 
Heretofore, in telephone communication for performing, for example, voice 
communication, there have been known various kinds of methods in which 
wireless communication is performed. They are, for example, a portable 
radiophone method (transmitting output: a few watts (W)) for performing 
wireless communication with a direct exchange (base station), such as a 
car telephone or the like, and a so-called cordless telephone method for 
performing communication with a network connecting device (base unit) 
connected to a wired communication network while moving only over a very 
restricted range such as indoors, using weak radio waves (transmitting 
output: a few milliwatts (mW)). 
Although different communication protocols are used in these wireless 
telephone methods, the hardware configurations of these mobile terminals 
are similar. Nevertheless, a conventional device is configured exclusively 
for either the portable radiophone method or the cordless telephone 
method. 
Consequently, in the case of a portable radiophone, use in a shielded 
structure is impossible, and in the case of a cordless telephone, 
conversation cannot be performed if there is not a base unit nearby. 
Therefore, in order to communicate while moving indoors and outdoors, 
heretofore, both portable radiophone and cordless telephone must be held. 
This results in a big investment in communication equipment. 
Problems also arise because, although it may not be deemed difficult to 
unify both functions of the portable radiophone and cordless telephone, 
troublesome operations, such as switching of switches or the like, are 
required for selecting either of the functions, and communication cannot 
be performed if a switch setting is wrong. Moreover, although it is 
desirable to select cordless telephone communication where there is a base 
unit nearby and the cordless telephone method can be used, because 
communication cost is high for the portable radiophone which can be freely 
moved outdoors, there is a possibility that the expensive portable 
radiophone method may be selected due to an unoptionized switch setting in 
a zone where both communication methods are possible. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to remove the above-described 
disadvantages of the prior art. 
It is a further object of the present invention to provide an improved 
wireless communication system. 
It is a still further object of the present invention to provide a wireless 
communication system which does not require troublesome operations and 
which can automatically select an optimum communication method. 
It is a still further object of the present invention to provide a 
communication terminal device which can automatically select a proper 
method among plural wireless methods in accordance with operation states 
of plural wireless communication methods having different communication 
protocols. 
It is still a further object of the present invention to provide a wireless 
communication system comprising wireless communication methods over a 
short distance and a long distance. 
It is still another object of the present invention to provide a wireless 
communication system which can reduce communication cost. 
It is still another object of the present invention to provide a wireless 
communication system which can store preferential orders of mobile 
stations when the mobile stations are registered in a fixed station, and 
which can control calling/call-receiving and communication processing 
according to the preferential orders. 
These and other objects of the present invention will become more apparent 
from the following detailed description taken in connection with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will be explained in detail based on the embodiments 
shown in the drawings. 
FIG. 1 shows a block diagram of a mobile terminal of a mobile telephone 
terminal device which adopts an embodiment of the present invention. In 
FIG. 1, a voice processing unit 1 for performing conversation via a 
handset (transceiver) 1a comprises a well-known anti-sidetone circuit, 
speech network circuit, calling circuit, call-receiving circuit and the 
like. In the voice processing unit 1, a control unit 8 comprising a 
microprocessor and the like is incorporated. A display unit 10 for 
displaying a telephone number, time, operation state or the like, and a 
keyboard 11 for inputting a telephone number for calling or the like are 
also connected to the voice processing unit 1. 
In the present embodiment, communication is performed by both the portable 
radiophone method which directly performs wireless communication with an 
exchange and the cordless telephone method which is connected to a wired 
network via a base unit (fixed station). Hence, wireless 
transmitting/receiving units 2 and 3 of the cordless telephone method and 
portable radiophone method are provided, respectively. 
A cordless telephone is used in general for wireless communication over a 
short distance, the transmitting output of which is 5 mW for both base 
unit and satellite unit in Japan's NTT. 
On the other hand, a portable radiophone is used for wireless communication 
over a long distance, and directly performs wireless communication with an 
exchange. The transmitting output is 5 W at the telephone side, and 25, 10 
or 5 W at the exchange side. 
In the present embodiment, the control unit 8 detects receiving states of 
signals at the wireless transmitting/receiving unit 2 of cordless 
telephone and the wireless transmitting/receiving unit 3 of portable 
radiophone. The control unit 8 further selects either of the wireless 
transmitting/receiving units in accordance with the receiving state at 
each of the wireless transmitting/receiving units 2 and 3, and makes 
communication possible. 
The voice processing unit 1 is connected to the wireless 
transmitting/receiving unit 3 of cordless telephone and wireless 
transmitting/receiving unit 3 of portable radiophone by means of 
well-known interface signals. Particularly, communication-range indicating 
signals 4 and 5 are input from the wireless transmitting/receiving unit 2 
of cordless telephone and wireless transmitting/receiving unit 3 of 
portable radiophone to the voice processing unit 1. 
In both the portable radiophone method and cordless telephone method, it is 
determined whether or not the mobile terminal is at a location where 
communication is possible by the method, according to the reception state 
of a predetermined signal. Communication-range indicating signals 4 and 5 
are signals showing the result of the determination. There has hitherto 
been indicated whether communication is possible or not according to these 
signals. 
In the present embodiment, a proper wireless transmitting/receiving unit is 
selected from the wireless transmitting/receiving unit 2 or cordless 
telephone and the wireless transmitting/receiving unit 3 of portable 
radiophone, using the communication-range indicating signals 4 and 5. 
FIG. 2 is a diagram showing a block diagram partly modified from the block 
diagram shown in FIG. 1 and an example of a system of the present 
embodiment. 
In FIG. 2, like components as in FIG. 1 are indicated by like numerals, and 
further explanation will be omitted. 
A voice processing unit 1' for performing conversation via a handset 1a 
comprises a speech network circuit, calling circuit, call-receiving 
circuit and the like. A RAM 8b is used as a memory for the operation of 
the control unit 8, or stores abbreviated dial keys and the like. A power 
supply 12 supplies electric power by means of a battery, dry cell or the 
like so that the device can be moved. 
A base unit (fixed station) 20 of a cordless telephone performs wireless 
communication with the wireless transmitting/receiving unit 2 of cordless 
telephone via antennas 23a and 23b. The base unit 20 of the cordless 
telephone is connected to an exchange 21 via a communication (telephone) 
network 24. 
An exchange 21, such as Japan's NTT or the like, performs connection 
between terminals via the communication network 24, and also performs 
wireless communication with the wireless transmitting/receiving unit 3 of 
portable radiophone via antennas 23c and 23e. An exchange 22 is located at 
a zone different from that of the exchange 21. 
When a mobile telephone terminal device controlled by the control unit 8 is 
moved by the operator, wireless communication can be performed with an 
exchange located in the neighborhood. 
That is, in the present embodiment, when a mobile telephone terminal device 
can perform wireless communication with the base unit 20 of cordless 
telephone, the control unit 8 selects the wireless transmitting/receiving 
unit 2 of cordless telephone, making possible voice communication using 
the wireless transmitting/receiving unit 2 of the cordless telephone. 
When the mobile telephone terminal device is located at a place remote from 
the base unit 20 of cordless telephone, and wireless communication by the 
wireless transmitting/receiving unit 2 of the cordless telephone is 
impossible, the control unit 8 selects the wireless transmitting/receiving 
unit 3 of portable radiophone, making possible voice communication by the 
wireless transmitting/receiving unit 3 of portable radiophone. 
FIG. 3 shows a communication control procedure performed by the control 
unit 8 shown in FIG. 1 or FIG. 2. The procedure shown in FIG. 3 is stored 
in a ROM 8a. 
First, at step S1, the control unit 8 receives calling operation such as 
telephone number input or the like from the keyboard 11. 
Then, at step S2, the wireless transmitting/receiving unit 2 of cordless 
telephone is started, and an initializing operation is performed so that 
communication by the cordless telephone method can be performed. 
At step S3, it is determined whether the wireless transmitting/receiving 
unit 2 of cordless telephone is within the range of cordless communication 
or not, according to the state of the communication-range indicating 
signal 4 which the wireless transmitting/receiving unit 2 of the cordless 
telephone outputs. When step S3 is affirmative, the control proceeds to 
step S6, where communication is performed by the wireless 
transmitting/receiving unit 2 of cordless telephone using the 
communication protocol in the cordless telephone method. 
On the other hand, when step S3 is negative, the wireless 
transmitting/receiving unit 2 of cordless telephone cannot be used. Hence, 
the step proceeds to step S4, where the wireless transmitting/receiving 
unit 3 of portable radiophone is started. 
Then, at step S5, it is determined whether the wireless 
transmitting/receiving unit 3 of portable radiophone is within the range 
of communication by the portable radiophone method or not, according to 
the state of the communication-range indicating signal 5 which the 
wireless transmitting/receiving unit 3 of portable radiophone outputs. 
When step S5 is affirmative, the control proceeds to step S7, where 
communication is performed by the portable radiophone method using the 
wireless transmitting/receiving unit 3 of portable radiophone. 
When step S5 is negative, communication is impossible by either of the 
cordless telephone and portable radiophone methods. Hence, communication 
is abandoned, and processing is terminated. 
Thus, according to the present embodiment, it is possible to provide a 
device which has both functions of the cordless telephone method and 
portable radiophone method in which communication protocols are different. 
It is also possible to automatically select a proper communication method 
utilizing communication-range indicating signals of the wireless 
transmitting/receiving unit 2 of cordless telephone and the wireless 
transmitting/receiving unit 3 of portable radiophone, by means of the 
above-described control method. Hence, operations such as troublesome 
switching of a switch or the like are unnecessary. 
Moreover, since priority is given to the cordless telephone method in the 
procedure shown in FIG. 3, it is possible to always utilize the cordless 
telephone method which has lower communication cost whenever the wireless 
transmitting/receiving unit 2 of cordless telephone can be used. This is 
advantageous in that communication cost can be minimized. 
FIG.4 shows a different control procedure of the control unit 8. While, in 
the procedure shown in FIG. 3, a wireless connecting unit is selected 
after the calling operation has been performed, in FIG. 4, when power from 
power supplies of the units have been applied at step S1', both the 
wireless transmitting/receiving unit 2 of cordless telephone and the 
wireless transmitting/receiving unit 3 of portable radiophone are set in 
waiting state, that is, in receiving state at step S2. 
The wireless transmitting/receiving unit 2 of cordless telephone and the 
wireless transmitting/receiving unit 3 of portable radiophone continuously 
monitor the received electric field in receiving state, that is, in 
waiting state, determining whether they are located within the range 
capable of communication or not, and generating the communication-range 
indicating signals 4 and 5. In the present embodiment, these procedures 
are utilized. That is, selection between the the wireless 
transmitting/receiving unit 2 of cordless telephone and the wireless 
transmitting/receiving unit 3 of portable radiophone is performed in 
waiting state through steps S3-S7. The selection processing at steps S3-S7 
is totally the same as that described above. 
By means of such control, it is possible to previously select a proper 
communication method in a waiting state prior to calling. Hence, 
processing time during calling and call-receiving can be reduced, and a 
faster processing than that shown in FIG. 3 is possible. 
Although the cordless telephone and portable radiophone methods have been 
illustrated in the foregoing description, any other communication methods 
may also naturally be used. 
As is apparent from the foregoing description, in the present embodiment, 
there is provided a configuration which comprises plural wireless 
transmitting/receiving means using different transmitting/receiving 
protocols, conversation circuits for performing conversations via these 
wireless transmitting/receiving means, and control means for allowing 
conversation using a proper wireless transmitting/receiving means between 
plural wireless transmitting/receiving means in accordance with operation 
states of the plural wireless transmitting/receiving means. Hence, it is 
possible to provide an excellent mobile telephone terminal device which 
can automatically select a proper communication method without any 
troublesome operation, and which provides low communication cost. 
Although, in the present embodiment, explanation has been provided 
illustrating communication in voice, the present invention is not limited 
to voice, and can also be used for the communication of image signals or 
character codes. 
Next, as a second embodiment of the present invention, an example in which 
plural mobile stations can be connected to a base unit (fixed station) of 
cordless telephone will be explained. 
There has hitherto been known a cordless telephone in which, as shown in 
the first embodiment, wireless connection is performed between a fixed 
station (base unit) connected to a network and a mobile station (satellite 
unit), and conversation is performed between the mobile station and the 
network. FIG. 5 shows the structure of a conventional cordless telephone. 
In FIG. 5, a fixed station 120 is connected to a communication network 
130. The fixed station 120 includes a wireless connection unit 108', which 
performs wireless connection with a mobile station 129 including a similar 
wireless connecting unit, and inputs and outputs voice signals during 
conversation. It is possible to perform thereby conversation with (a 
station in conversation via) the communication network 130 via the mobile 
station. Since full duplex communication is performed, an up channel UC 
and a down channel DC using different frequency bands are set as 
conversation channels between the fixed station 120 and the mobile station 
129. 
A control channel for controlling calling, call-receiving or a network is 
also set as well as the conversation channels. The control channel is 
configured using a frequency band which is different from those of the 
above-described conversation channels. When one-to-one communication is 
performed between the fixed station and the mobile station, the control 
channel is used only when conversation is not performed. Accordingly, is 
such system, the wireless connection unit 108' of the fixed station 120 
and the similar wireless connecting unit of the mobile station are 
configured so that communication can be performed via either of the 
conversation channels and control channel by switching of a frequency 
control circuit or the like. 
In the conventional case, a multichannel access (MCA) method is being used, 
supposing not only one-to-one communication between a fixed station and a 
mobile station, but also a case in which plural cordless telephone systems 
are used within the same area, such as a building or the like. The MCA 
method is a method in which plural communication channels which can be 
used between a fixed station and a mobile station are set together with 
conversation channels and a control channel, each channel is scanned at 
the fixed station or mobile station, and a conversation channel or control 
channel which is not being used for communication is selected for use. 
There has also been considered a method in which ID codes for identifying 
mobile stations are provided in order to connect plural mobile stations 
for one fixed station. 
Next, the operation of the conventional cordless telephone shown in FIG. 5 
will be briefly explained. When calling is performed, for example, from 
the mobile station 129, a general notifying signal (signal for permission 
of calling) transmitted from the fixed station is received via the control 
channel. When it is confirmed that calling is possible, the mobile station 
129 transmits a control signal consisting of synchronizing signal, system 
code, mobile-station ID, calling signal and the like. 
When this control signal is received via the wireless connection unit 108', 
the fixed station 120 performs the collation of the ID code, outputs a 
calling response signal if a predetermined criterion is satisfied, scans 
vacant conversation channels, and transmits a signal for assigning a 
conversation channel to be used for communication. 
When the channel-assigning signal is received, the mobile station 129 
performs switching from the control channel to the communication channel, 
and awaits a loop-check signal (connection-confirming signal). When it is 
confirmed by this signal that wireless connection has been completely 
performed, the mobile station 129 completes calling connection of wireless 
connection by transmitting a confirmation response signal, closes the loop 
of the connected subscriber circuit (in some cases, plural circuits) 130, 
and performs a calling connection between the subscriber circuit 130 and 
the mobile station 129. 
At this stage, there is provided a state which is the same as when the 
operator takes the receiver at a normal wired telephone. Now, dial data 
are transmitted to the fixed station using the conversation channel in 
accordance with dialing. The fixed station outputs the dial signal 
transmitted as a voice signal to the communication network 130, and calls 
a station to be called. Conversation is performed hereafter in the same 
manner as in the normal telephone. 
When conversation has been completed and hanging-up, or "hook-off" of the 
hand set (or an operation corresponding thereto) is performed at the 
mobile station 129, a hung-up signal is transmitted from the mobile 
station 129 using the up channel of the conversation channels. The fixed 
station 120 thereby opens the loop of the communication network 130, and 
outputs a disconnecting signal through the down channel to terminate 
wireless connection processing. 
On the contrary, when there is a call-reception at the fixed station 120 
through the communication network 130, the fixed station 120 first 
searches vacant conversation channels with performing channel scan, 
transmits a channel-assigning signal to the mobile station, and outputs an 
RG-starting signal (signal for ringing the bell of the mobile station), 
after confirming wireless connection with the mobile station by performing 
a loop check of the assigned channel in the same manner as described 
before. 
The mobile station 129 thereby generates a call signal, and awaits the 
operator hanging up or the time-out of a predetermined waiting time. When 
there is hook-off, the mobile station 129 transmits a hook-off signal to 
the fixed station, closes the loop of the communication network 130, and 
performs conversation operation until there is hook-on, or a disconnecting 
signal from the fixed station is received. 
When a hook-on (lifting of a receiver from its cradle or hook) signal is 
transmitted from the mobile station 129 on the occasion of termination of 
conversation, the fixed station 120 transmits a disconnecting signal to 
the mobile station after opening of the circuit loop, and processing is 
terminated. 
As described above, in the multichannel access method, plural systems 
comprising a fixed station and mobile stations can be operated within the 
same zone. In that case, even a mobile station registered in another fixed 
station can be connected to the network under the equivalent treatment, if 
only it has been registered in a certain fixed station. 
Accordingly, there may happen a case in which, within one fixed-station 
area, there exist mobile stations exceeding the number of networks to 
which the fixed station is connected. When, for example, mobile stations 
which should originally belong to another fixed station are duplicatedly 
registered in a fixed station in which the same number of mobile stations 
as the number of networks have already been registered, there results 
concurrence among mobile stations, giving rise to the problem that 
initially registered mobile stations have to await a vacancy in networks. 
In addition, in the conventional device, relative to a form in which the 
registration of a mobile station in a fixed station can easily be 
rewritten, the ID code of the mobile station may be registered using a 
memory such as a RAM or the like. However, when a memory such as a RAM or 
the like is used, it is necessary always to provide a power supply to the 
memory in order to preserve data, and a backup power supply or the like is 
also required in order to deal with situations such as power failure or 
the like. These requirements cause the problems that the configuration of 
the fixed station becomes complicated, and production cost increases. 
The second embodiment of the present invention solves the above-described 
problems. 
Now, the second embodiment of the present invention will be explained in 
detail with reference to the drawings. 
FIG. 6 shows the system of a cordless telephone in which the second 
embodiment of the present invention is adopted. Here, there are shown two 
systems each of which comprises one fixed station 121, 122, and two mobile 
stations 123 and 124, 125 and 126, respectively. In FIG. 6, there are 
shown wireless zones 113 and 114 of the fixed staions 121 and 122, 
respectively. The mobile stations 123-126 have ID codes "111", "112", 
"221" and "222" as shown within each block (three-digit ID codes are used 
here for the simplification of explanation), respectively, and each of 
these ID codes is registered in a memory of each mobile station. 
The configuration of the mobile stations is the same as before, and hence 
detailed explanation thereof will be omitted. On the other hand, the fixed 
stations 121 and 122 are configured as shown in FIG. 7. 
In FIG. 7, a communication circuit 131 (or 132) is connected to a 
circuit-interface circuit 104 of the fixed station 121 (or 122). 
The circuit-interface circuit 104 comprises a call-receiving detection 
circuit, circuit-connection control circuit, speech network circuit and 
the like. The circuit-interface circuit 104 also includes a dial-signal 
transmitting unit for transmitting a dial signal (pulse or tone signal) 
corresponding to dial data provided from the control unit 106 to the 
communication circuit 131. 
The circuit-interface circuit 104 is connected to a wireless connection 
unit 108. The wireless connection unit 108 comprises a 
modulator/demodulator, frequency control circuit, transmitting/receiving 
amplifier and the like. In the wireless connection unit 108, there are 
provided a conversation-channel transmitting/receiving circuit which can 
simultaneously access to a sufficient number of conversation channels that 
conversation processing of one or plural mobile stations can be performed 
in accordance with specification, and a control-channel 
transmitting/receiving circuit which accesses to a full-duplex control 
channel common to all mobile stations. One transmitting/receiving circuit 
may also be used by being switched for a control channel and for a 
conversation channel. An antenna A1 is connected to the wireless 
connection unit 108. 
Operation of the fixed station 121 is controlled by the control unit 106 
which comprises a microprocessor and the like. The control unit 106 
includes a ROM 106a and a RAM 106b. The ROM 106a is used for storing 
control programs which are to be described later, and the RAM 106b is used 
as a work area of the control unit 106. An operation unit 107 which 
comprises a ten-key and a display unit or a speaker used for generating 
ringing tone, alarm tone or the like, and the like is connected to the 
control unit 106. The operation unit 107 is configured as shown in FIG. 8. 
In FIG. 8, there is shown a ten-key 204 for inputting dial data. A 
registration key 206 and a clear key 202 are provided in a lower portion 
of the ten-key 204. The registration key 206 is used for controlling the 
registration of ID codes and preferential orders to be described later of 
mobile stations in an EEPROM 111. The clear key 202 is used for the 
above-described registration, data clear of redialing or the like. 
In FIG. 6, the fixed stations 121 and 122 can be connected to two 
communication networks 131 and 132, respectively, and communication can 
simultaneously be performed between two mobile stations 123 and 124, and 
125 and 126, and the networks. In that case, it is also possible to 
register two or more mobile stations in the fixed stations 121 and 122. It 
is possible to register, for example, the mobile stations 125 and 126 in 
addition to the mobile stations 123 and 124 in the fixed station 121. 
In this case, a mere registration may cause concurrence among mobile 
stations as described in the explanation of the conventional case, and 
thus communication may become impossible. Consequently, in the present 
embodiment, a desired preferential order is set in addition to the 
identification code on the occasion of the registration of a mobile 
station through a procedure as shown in FIG. 9, and communication 
processing is controlled in accordance with the preferential order. 
Control procedures shown in other figures, and described below, are stored 
in the ROM 106a in FIG. 7. 
When the registration key 206 is depressed as shown in step S101 in FIG. 9 
(A), the step proceeds to the registration processing of a mobile station. 
First, at step S102, data input following the registration key are 
buffered in a register. Then, at step S103, it is determined whether the 
input data coincide with a predetermined administrator's code, for 
example, an undertaker's number of the fixed station to be registered in, 
a system number or the like. When step S103 is affirmative, the control 
proceeds to step S104, where identification codes of mobile stations which 
are now registered are displayed on the display unit of the operation unit 
107. 
The operator then inputs the ID code and data of a desired preferential 
order of the newly-registered mobile station. This input is performed by 
the ten-key 204 shown in FIG. 8, and the input is determined at steps 
S105-S109. 
At step S105, in the case of registering the ID code of a mobile station, 
for example, newly registering the mobile station 125 or 126 in the fixed 
station 121, it is determined whether "221" or "222" or the like has been 
input or not. When the ID code has been input, the step proceeds to step 
S106. When there has been no input, the step proceeds to step S111. 
At step S106, it is determined whether the ID code having a predetermined 
digit number (3 digits in the case of FIG. 6) has been input or not. When 
there has been no input of the predetermined digit number, the step 
returns to step S105. When the ID code having the predetermined digit 
number has been input, the step proceeds to step S107. 
At step S107, it is determined whether the preferential order has been 
input or not. The preferential order is input, for example, in the form of 
number such as 1, 2, ---, or the like. When there has been the input of 
the preferential order, the control proceeds to step S114 shown in FIG. 9 
(B). When there has been no input of the preferential order, the control 
proceeds to step S108. At step S108, it is determined whether the clear 
key 202 has been depressed or not. When the clear key has been depressed, 
the control proceeds to step S112. When the clear key has not been 
depressed, the control proceeds to step S109. 
At step S109, it is determined whether the registration key 206 has been 
depressed again or not. When the registration key has not been depressed, 
the control returns to step S107. When the registration key has been 
depressed, the control proceeds to step S110. At step S110, when 
registration has been performed in the main mobile station, that is, in 
the fixed station 121 in FIG. 6, an identification code which has been 
input together with the preferential-order code equivalent to those of the 
mobile stations 123 and 124 is stored in the EEPROM 111. It is to be noted 
that, in the case of no assignment of a preferential order, the lowest 
preferential order, not the highest, may automatically be selected at step 
S110. 
When the clear key 202 has been depressed at step S108, the step proceeds 
to step S112, where, if there is a registered ID code, the ID code is 
erased from the EEPROM 111. When there is no registration of ID code, the 
input identification code is cleared from the register on the buffer. At 
step S113, it is determined whether there has been any key input or not. 
If there has not been, registration processing is terminated. If there has 
been a key input, the control returns to step S105. 
On the other hand, when there has been the input of the preferential order 
at step S107, it is determined whether the registration key 206 has been 
depressed or not at step S114 in FIG. 9 (B). When the registration key has 
not been depressed, the control proceeds to step S107. When the 
registration key has been depressed, the identification code which has 
been input up of that time is stored in the EEPROM 111 together with the 
input preferential-order code. As described above, it is possible to 
perform a registration processing which stores a code indicating a 
preferential order together with an identification code relative to a 
certain fixed station in the EEPROM 111. It is possible to control 
communication by the following procedure, using the registered ID code and 
preferential order. In FIGS. 10 (A) and 10 (B), there are shown basic 
processing procedures of a fixed station and a mobile station. The 
procedure of the fixed station is stored in the ROM 106a, and the 
procedure of the mobile station is stored in a ROM (not illustrated) or 
the like connected to the control unit of the mobile station. 
When power from the power supply of the fixed station has been applied, the 
control unit 106 of the fixed station performs the procedure shown in FIG. 
10 (A). First, at step S116, a general notifying signal is transmitted 
through a predetermined control channel. At step S117, then, the control 
enters a waiting operation. At steps S118 and S119, a calling from the 
mobile station and the reception of a call signal from the network are 
determined, respectively. When there has been a calling from the mobile 
station, processing for calling the mobile station is performed at step 
S120. When a call signal from the network has been received, the control 
proceeds to call-reception processing of the mobile station at step S121. 
On the other hand, when power from the power supply of the mobile station 
has been applied, the control unit of the mobile station first performs 
the initial setting of each unit of the device at step S122 in FIG. 10 
(B), and then performs acquisition operation of a control channel at step 
S123. In this procedure, a certain control channel is selected at step 
S124, and by determining the system code of the fixed station transmitted 
to that control channel at step S125, the control proceeds to a waiting 
operation at step S126. When the system code has not been correct at step 
S125, channel setting at step S124 is performed again. 
In waiting operation, determinations of an off-hook state of the handset, 
receptions of the channel-assigning signal and call-receiving signal from 
the fixed station, and whether communication is out of the communication 
range or not by determining the signal level of the control channel and 
the like, are performed at steps S127-S129, respectively. In the case of 
an off-hook state, the step proceeds to calling operation at step S130. 
When there has been a call-reception, the control proceeds to step S131. 
When it has been determined that communication is out of the communication 
range, the control returns to step S123, where setting processing is 
performed again from the acquisition of a control channel. 
Now, in FIGS. 11 (A)-11 (C), a call-receiving procedure to the mobile 
station by the fixed station at step S121 in FIG. 10 (A) is shown. 
The control unit 106 of the fixed station first determines whether there is 
a vacancy in conversation channels or not at step S132 in FIG. 11 (A). If 
there is a vacancy, the loop of the circuit is closed at step S133. At 
steps S134 and 135, it is determined whether the second dial (the number 
of the mobile station) has been transmitted from the calling station via 
the network. When the second dial has been received, it is collated with 
the ID code stored in the EEPROM 111 at step S136 in order to investigate 
whether the mobile station has been registered or not. When the mobile 
station has not been registered, the loop of the circuit is opened at step 
S138, and the control returns to waiting operation at step S138'. 
When the corresponding mobile station has been registered, a 
channel-assigning signal corresponding to the vacant conversation channel 
is transmitted to the assigned mobile station by the second dial at step 
S137, and the loop check is performed at steps S139 and S140. When the 
confirmation response signal of the loop check has been transmitted from 
the mobile station, the control proceeds to step S141, where an 
RG-starting signal is transmitted to the mobile station to generate a 
ringing tone. 
Subsequently, at step S142, an off-hook state of the mobile station is 
detected. In the case of such off-hook state, the control proceeds to step 
S143. In the case of the station still being on-hook, time-out of a 
predetermined call time is determined at step S148. When the call time is 
not time-out, calling from step S141 is continued. In the case of 
time-out, opening of the circuit loop, transmission of a disconnecting 
signal to the mobile station, and reception of a hung-up signal 
corresponding thereto are respectively performed and determined at steps 
S149-S151. After proceeding to the reception of the hung-up signal, the 
control then proceeds to waiting operation at step S152. 
When there has been an off-hook state at the mobile station in response to 
calling, it is determined whether the preferential order of the called 
mobile station is the highest or not in reference with the EEPROM 111 at 
step S143. When the preferential order is the highest, the control 
proceeds to conversation operation at step S144. When the preferential 
order is not the highest, the control proceeds to step S161. 
In the case of the highest preferential order, conversation operation at 
step S144 is unconditionally performed. When entered in conversation 
processing, time-out of a predetermined conversation time (this may not be 
provided), on-hook of the circuit side and a hung-up signal from the 
mobile station are detected at steps S145-S147, respectively. In the case 
of time-out and off-hook at the circuit side, the step proceeds to 
disconnecting processing after step S157. When the hung-up signal has been 
received, the step proceeds to hang-up operation at step S153. The 
disconnecting operation is realized at steps S158-S160 by the completely 
same processing as that in the above-described steps S149-S151. 
Hang-up operation is realized by opening of the circuit loop and 
transmission of a disconnecting signal to the mobile station at steps S154 
and S155, respectively. When steps S155 and S160 have been terminated, the 
step proceeds to waiting operation at step S156. 
On the other hand, when the preferential order of the called mobile station 
is not the highest at step S143, the step proceeds to step S161 in FIG. 11 
(B). At step S161, switching to the control channel is performed, and 
using this channel, a general notifying signal corresponding to a calling 
permission signal is transmitted. That is, when the station in 
conversation is not the highest-ranking station, a calling request is made 
possible even when conversation channels are fully utilized. Then, at step 
S162, it is determined whether other mobile stations are performing 
calling request or not. When there is a calling request, the control 
proceeds to step S175 in FIG. 11 (C). When there is no calling request, 
the called station is subjected to conversation operation at step S163. 
During conversation operation, reception of a hung-up signal, time-out of 
conversation time and on-hook state of the circuit side are determined at 
steps S164-S166, respectively. When steps up to step S166 have been 
performed, with a negative determination in each, the control returns to 
scanning of other calling stations at step S162. In the case of time-out 
of conversation time and on-hook of the circuit side, the step returns to 
disconnection operation at step S167. That is, at steps S168-S170, 
disconnecting processing is performed by the same processing as that in 
the above-described steps S140-S151. When a hung-up signal from the mobile 
station has been received, the step proceeds to hang-up operation at step 
S171. That is, at steps S172 and S173, the same processing as that in the 
above-described steps S154 and S155 is performed. When steps S170 and S173 
have been terminated, the control proceeds to waiting operation at step 
S174. 
When there is a calling request from another station at step S162 after the 
commencement of conversation at step S163, the control proceeds to step 
S175 in FIG. 11 (C), where it is determined whether the ID code of the 
calling-requesting station is stored in the EEPROM 111 or not. When the 
calling-requesting station is not registered, the control proceeds to step 
S163. 
When the ID code of the calling station is registered, it is determined 
whether the preferential order of the calling-requesting station is higher 
than that of the station in conversation or not. When the preferential 
order of the calling-requesting station is lower, a calling-rejecting 
signal is transmitted to the calling-requesting station using the control 
channel, and calling rejection in performed at step S180. 
When the preferential order of the station in conversation is lower, the 
control proceeds to step S177, where a predetermined alarm signal is 
output to the mobile station in conversation, and a calling response 
signal is output to the calling-requesting mobile station to permit 
calling. 
At step S178, waiting for a predetermined time is performed in order to 
permit the station in conversation, time for terminating the conversation. 
Then, at step S179, a disconnecting signal is output to the mobile station 
in conversation to perform disconnection processing in which the circuit 
loop is opened. 
As described above, it is possible to perform call-reception even to a 
mobile station having a low preferential order, and to interrupt the 
communication of the mobile station in conversation in accordance with the 
preferential order when a station having a preferential order which is 
higher than that of the station has requested a calling during 
conversation. 
Next, a routine for processing a calling from the mobile station side at 
step S120 in FIG. 10 (A) is shown in FIGS. 12 (A)-12 (C). 
When there is a calling request from the mobile station, it is determined 
whether the ID code of the calling-requesting station is stored in the 
EEPROM 111 or not at step S181 in FIG. 12 (A). When the ID code is not 
registered, the control proceeds to waiting operation at step S182. When 
the ID code is registered, a calling response signal for permitting a 
calling is transmitted at step S183. 
Then, at step S184, a dial signal for calling the police or a fire 
department is detected. When such dial signal for emergency is transmitted 
from the mobile station, the control unconditionally proceeds to step 
S201, where a vacancy in conversation channels is searched. At step S202, 
the loop of the circuit is closed, and the input dial signal is 
immediately transmitted. 
When no dialing for emergency has been found at step S184, the circuit loop 
is closed and the dial signal transmitted from the mobile station is sent 
out to the circuit at steps 185 and 186, respectively. 
At step S187 and the loop of S198-S200, detection of a predetermined time 
of off-hook state at the circuit side and detection of a hung-up signal of 
the mobile station are performed. When off-hook state of the circuit side 
has not been detected during the predetermined time, the control proceeds 
to waiting operation at step S212. When there has been detected an 
off-hook state of the circuit side, the control proceeds to step S188, 
where a calling guide is transmitted to the circuit, and the control then 
proceeds to wireless connection after step S189. 
At step S189, a vacant conversation channel is searched by means of channel 
scanning. When there is a vacant channel, a channel assigning signal is 
transmitted to the mobile station to determine a conversation channel to 
be used, at step S190. 
At steps S191 and S192, the loop check of the conversation channel is 
performed, the control then proceeds to step S193 when wireless connection 
has been established. 
At step S193, it is determined whether the preferential order of the 
calling mobile station is the highest or not. When the preferential order 
of the mobile station is not the highest, the control proceeds to step 
S213 in FIG. 12 (B). When the preferential order is the highest, the 
control proceeds to step S194. 
At step S194, the same conversation operation as that described above is 
performed. During conversation, at steps S195-S197, detection of a hung-up 
signal, time-out of conversation time and detection of off-hook at the 
circuit side (this detection may be omitted when it is intended to reduce 
the cost of the device) are performed, respectively. When the hung-up 
signal has been received, entirely the same hang-up operation as that 
described before is performed at step S208 (the actual operations are 
steps S209 and S210). In the case of an on-hook state at the circuit side 
or of a time-out, entirely the same disconnection processing as that 
described before is performed at step S204 (the actual operations are 
steps S204-S207). When the disconnecting or hang-up processing has been 
terminated, the control returns to waiting operation at step S211. 
On the other hand, when the preferential order of the mobile station is not 
the highest, the control proceeds to steps S213 in FIG. 12 (B). Steps 
S213-S226, and steps S227-S232 in FIG. 12 (C) are entirely the same as 
steps S161-S180 in FIGS. 11 (B) and 11 (C) for call-reception to the 
mobile station. 
That is, after a general notifying signal has been transmitted at step 
S213, a calling request of an other mobile station is detected at step 
S214. When there is a calling request, the control proceeds to step S227 
in FIG. 12 (C). When there is no calling request, the control proceeds to 
conversation processing at step S215. Then, a hung-up signal, time-out of 
conversation time and an off-hook state of the circuit side are detected 
at steps S216-S218, respectively. When the hung-up signal has been 
detected, hang-up operation is performed at step S223 (the actual 
operations are S224 and S225). In the case of an off-hook state at the 
circuit side or of a time-out, disconnection processing is performed at 
step S219 (the actual operations are S220-S222), and the control returns 
to waiting operation at step S226. 
The calling-request detection at step S214 is repeated during conversation, 
and when there is a calling request, the control proceeds to step S227 in 
FIG. 12 (C), where the presence of ID registration of the 
calling-requesting mobile station is detected. When there is no ID 
registration, the control returns to conversation processing at step S215. 
At step S228, the preferential orders of the calling-requesting station and 
the station in conversation are compared. When the preferential order of 
the calling-requesting station is lower, the calling request is rejected 
at step S232, and the step returns to step S214. 
When the preferential order of the station in conversation is lower, alarm 
is generated to the station in conversation, and after waiting for a 
predetermined time at step S230, the connection of the station in 
conversation is disconnected, and the control then returns to step S184 in 
FIG. 12 (A). 
As described above, even when a calling has been performed from a mobile 
station, it is possible to give priority to a calling or conversation of a 
station having a higher preferential order, by comparing preferential 
orders. 
Next, control at the mobile station side will be explained with reference 
to the flow charts in FIGS. 13 and 14. The procedures in FIGS. 13 and 14 
show programs of a control unit (not illustrated) of the mobile station. 
FIGS. 13 (A) and 13 (B) show the call-reception operation of the mobile 
station at step S131 in FIG. 10 (B). 
When channel-assigning and call-receiving commands have been received, the 
mobile station performs switching to an assigned conversation channel at 
step S233 in FIG. 13 (A), receives a loop-check signal at step S234, and 
then transmit a confirmation response signal at step S235. 
At step S236, an RG-starting signal is waited. When this signal has been 
received, the generation of a ringing tone and off-hook operation 
(receiver pickup) by the operator are awaited at steps S237 and S238, 
respectively. 
When there is an off-hook state, an off-hook signal is transmitted to the 
fixed station at step S239, and the program then proceeds to conversation 
processing at step S240. 
First, an alarm signal is detected at step S241. This detected signal is 
transmitted when, as described above, the preferential order of the mobile 
station in conversation is low, and it is intended to terminate 
conversation forcibly. When the alarm signal has been transmitted, the 
control proceeds to step S250 in FIG. 13 (B). 
When the alarm signal has not been transmitted, the detection of an on-hook 
state is performed at step S242. When the operator has effected an on-hook 
state (hung up the receiver), the control proceeds to hang-up operation at 
step S247. When there is not an on-hook state, the control proceeds to 
step S243. 
At step S243, it is detected whether a disconnecting signal from the fixed 
station side has been received or not. When the disconnecting signal has 
been received, disconnection operation is performed at step S244. That is, 
a hung-up signal is transmitted to the fixed station at step S245. 
On the other hand, in the hang-up operation at step S247, a hung-up signal 
is transmitted at step S248, and loop processing in which a disconnecting 
signal from the fixed station is waited is performed at step S249. When 
the disconnecting signal has been received, the control proceeds to 
waiting operation at step S246. 
When the alarm signal has been received at step S241, an alarm tone is 
generated from a receiver speaker, and at the same time, a timer 
comprising a software for repeatedly generating the alarm tone at a 
predetermined time interval and the like is started to notify the operator 
that disconnection will be performed, at step S250 in FIG. 13 (B). 
Subsequently, in the loop of steps S251 and 252, detection of a 
disconnecting signal from the fixed station and detection of overflow of 
the timer started at step S250 are performed, respectively. In the case of 
overflow of the timer, the control returns to step S250, where alarm tone 
is generated again. The time interval to be set in the timer may be a 
suitable time, such as every a few seconds or the like. 
When the disconnecting signal has been received, disconnection operation is 
performed at step S253. That is, a hung-up signal is transmitted at step 
S254, and the control returns to waiting operation at step S255. 
The above-described call-reception processing of the mobile station is the 
same as that in the conventional case except as to the treatment of an 
alarm signal. When an alarm signal has been received during conversation, 
a mobile station having a preferential order higher than that of own 
station is performing a calling. Hence, an alarm tone is generated at a 
predetermined time interval until wireless connection is forcibly 
terminated by the fixed station, to force the termination of conversation. 
FIGS. 14 (A)-(C) show the control procedure of calling processing of the 
mobile station at step S130 in FIG. 10 (B). 
The mobile station performs reception of a general notifying signal and 
detection of calling by means of effecting an off-hook state at steps S256 
and S257, respectively. 
In the case of calling, the control proceeds to step S258, where a call 
signal is transmitted to the fixed station. 
In the loop of steps S259, S260 and S275, detection of the reception of a 
calling response signal from the fixed station, detection of a 
calling-rejecting signal and detection of an on-hook state are performed, 
respectively. In the case of reception of the calling response signal, the 
control proceeds to step S261. When the calling-rejecting signal has been 
received due to the above-described determination of preferential order by 
the fixed station, the control proceeds to step S281 in FIG. 14 (B). In 
the case of an on-hook state, the control proceeds to step S276. 
At step S261, a conversation-channel assigning signal of the fixed station 
is detected. When there has been channel assignment, the control proceeds 
to step S262. When there has been no vacancy in conversation channels and 
so there has been no channel assignment, the control proceeds to step 
S276'. 
At step S262, the conversation channel is switched to the assigned channel. 
At step S263, reception of a loop-check signal is detected. 
When wireless connection has been confirmed, the control proceeds to 
conversation processing at step S265. That is, an alarm signal from the 
fixed station is detected at step S266, and when the alarm signal has been 
detected, the control proceeds to step S284 in FIG. 14 (C). 
In the case of no alarm signal, detections of an on-hook state and a 
disconnecting signal from the fixed station are performed at steps S267 
and S272, respectively. In the case of an on-hook state, hang-up 
processing is performed at step S268 as in the case of FIG. 13 (A) (the 
actual operations are transmission of a hung-up signal and detection of a 
disconnecting signal at steps S269 and S270, respectively). When the 
disconnecting signal has been received, disconnection operation is 
performed at step S273 (the actual operation is hung-up signal 
transmission processing at step S274). When steps S270 and S274 have been 
terminated, the control proceeds to waiting operation at step S271. 
On the other hand, in the case of an on-hook state before wireless 
connection at step S275, an abandon operation is performed at step S277. 
That is, a hung-up signal is transmitted to the fixed station at step 
S278, and the control then proceeds to waiting operation at step S280. 
When there has not been a vacancy in conversation channels at step S261, 
the control proceeds to step S276', where a disconnecting signal from the 
fixed station is detected. When the disconnecting signal has been 
detected, the control proceeds to waiting operation at step S277'. When 
the disconnecting signal has not been received, the operator effecting an 
on-hook state is detected at step S276. When there is not an on-hook state 
at step S276, the step returns to detection of a channel-assigning signal 
at step S261. In the case of on-hook, the control proceeds to an abandon 
operation at step S277. 
When a calling-rejecting signal has been received at step S260, a timer for 
calling covering a predetermined time is started at step S281 in FIG. 14 
(B), and in the detection loop of steps S282 and S283, an on-hook state 
effected by the operator and overflow of the timer started at step S281 
are detected, respectively. In the case of an on-hook state, the control 
proceeds to step S277 in FIG. 14 (A). In the case of overflow of the 
timer, the control returns to step S256 in FIG. 14 (A). 
On the other hand, when an alarm signal has been received at step S266, 
alarm tone is generated from the speaker, and at the same time a timer for 
generating an alarm tone at a predetermined time interval is started at 
step S284 in FIG. 14 (C), as in the case of FIG. 13 (B). Then, at steps 
S285 and S286, detection of a disconnecting signal from the fixed station 
and detection of overflow of the timer started at step S284 are performed, 
respectively. 
When the disconnecting signal has been received, the control proceeds to 
disconnection operation at step S287. That is, a hung-up signal is 
transmitted at step S288, and a waiting operation is performed at step 
S290. When overflow of the timer has been produced at step S286, an alarm 
tone is generated again at step S250. 
As described above, in calling processing of the mobile station, as well as 
in the case of call-reception processing, a mobile station having a 
preferential order higher than that of a given station is calling, when an 
alarm signal has been received during conversation. Hence, an alarm tone 
is generated at a predetermined time interval until wireless connection is 
forcibly terminated by the fixed station, to force the termination of 
conversation. 
In the above-described second embodiment, when a mobile station capable of 
calling and call-reception is registered in the fixed station, the desired 
preferential order is stored together with the ID code, and communication 
is controlled according to the preferential order. Hence, it is possible 
to give priority to the communication of a mobile station having a higher 
preferential order, even when more mobile stations than the number capable 
of simultaneous communications have been registered. 
Furthermore, since the information about ID codes and preferential orders 
can be freely modified, flexible use in accordance with the application 
status of the users is possible. 
Moreover, the information about ID codes and preferential orders is stored 
in the EEPROM of the fixed station, whereby power consumption of the fixed 
station is reduced, and there is no need of a backup power supply or the 
like. Hence, the configuration of the device becomes simple and of low 
cost. In addition, it is possible to maintain securely the registered 
information even in the case of power failure or the like. If it is 
arranged so that feeding of electric power to the EEPROM 111 is performed 
only when the EEPROM is accessed, it is possible to increase the effect of 
reduction in power consumption. 
It is to be noted that, although the configuration of the cordless 
telephone has been illustrated above, the communication method is not 
limited thereto. The present invention can also be applied to various 
kinds of devices, such as a cordless terminal, facsimile or the like 
performing processing via a similar wireless connection. 
As is apparent from the above description, according to the second 
embodiment of the present invention, in a communication device comprising 
a fixed station which is connected to a predetermined communication 
network, and mobile stations which are wirelessly connected to the fixed 
station and which perform communication of a predetermined method with the 
communication network via the fixed station, the fixed station is provided 
with means for storing the identifying information of the mobile stations 
capable of being connected to the fixed station together with the 
information indicating the desired preferential orders of the mobile 
stations, and means for editing the identifying information of the mobile 
stations and the information relative to the preferential orders of the 
mobile stations within the storage means, and calling/call-reception and 
communication processings are controlled according to the preferential 
orders stored in the storage means. Hence, when the mobile stations are 
registered in the fixed station, it is possible to control 
calling/call-reception and communication processings according to the 
preferential orders. Thus, the present invention provides the excellent 
effect that, when many mobile stations are registered in the fixed 
station, it is possible to prevent the occurrence of incapability of 
communication as much as possible. 
While the present invention has been explained in reference to the 
preferred embodiments, it is not limited thereto. It is apparent that 
various changes and modifications may be made within the scope of the 
appended claims.