Wireless telephone set

A wireless telephone set comprise control circuit for controlling the transmission and the reception of signals, and a power switch for controlling the supply of a power to the control circuit. The power switch is turned ON to supply the power to the control circuit in response to each of frame signals, and is turned OFF when the wireless telephone set is in a waiting state for waiting an arriving call directed to the wireless telephone set, thereby the power consumption in the control circuit is reduced.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a wireless telephone set such as a digital 
wireless telephone equipment and so forth, which is operable in a power 
saving mode. 
2. Description of the Related Art 
FIG. 1 is a block diagram showing a conventional wireless telephone set. In 
the figure, reference numeral 1 is an antenna for transmitting and 
receiving electromagnetic wave, and 2 is a duplexer for distributing 
transmitting high frequency signals to the antenna 1 and for coupling 
receiving high frequency signals from the antenna 1. Reference numeral 3 
is a transmitter for converting a voice electric signal into the 
afore-mentioned transmitting high frequency signal, and 4 is a microphone 
for converting a voice into the above-mentioned voice electric signal. 
Reference numeral 5 is a receiver for converting the above-mentioned high 
frequency signal into a voice electric signal, and 6 is a speaker for 
converting the voice electric signal into a voice. Reference numeral 7 is 
a transmitter-side power switch for turning ON or OFF of the power 
supplied to the above-mentioned transmitter 3, and 8 is a receiver-side 
power switch for turning ON or OFF of the power supplied to the 
above-mentioned receiver 5. Reference numeral 9 is a battery for supplying 
a power to the whole of this wireless telephone set, and 10 is a main 
switch for turning ON or OFF of the supply of the power from the battery 
9. The above-mentioned transmitting-side power switch 7 and the 
receiving-side power switch 8 are connected through this main switch 10 to 
the battery 9. 
Further, reference numeral 11 is a reference signal oscillator which 
directly receives the power supplied from the battery 9 through the main 
switch 10 to oscillate to generate a reference signal, and 12 is a 
frequency dividing circuit for dividing the reference signal generated by 
the reference oscillator 11 to output frame pulses. Reference numeral 13 
is a timing generating circuit for controlling the timing of the 
transmission and the reception by controlling the abovementioned 
transmitter 3, the receiver 4, the transmitting-side power switch 7, the 
receiving-side power switch 8, and so forth, and 14 is a timing circuit 
power switch, connected to the battery 9 through-the main switch 10, for 
turning ON or OFF of the power supplied to the timing generating circuit 
13. Reference numeral 15 is a microprocessor as a control circuit for 
controlling the frequency dividing circuit 12, the timing generating 
circuit 13, the timing circuit power switch 14 and so forth, based on the 
frame pulses outputted from the above-mentioned frequency dividing circuit 
12. In this connection, the power supply to the microprocessor 15 is 
directly effected from the main switch 10. 
Next, the operation of the conventional circuit shown in FIG. 1 will be 
described. When the main switch 10 is turned ON, the microprocessor 15 is 
supplied with a power to start its operation so as to initialize the 
frequency dividing circuit 12. After that, during a waiting state for 
waiting an arriving call to the wireless telephone set under consideration 
(hereinafter simply referred to as a waiting state), the microprocessor 15 
instructs the timing generating circuit 13 to turn OFF the 
transmitting-side power switch 7 and the receiving-side power switch 8, 
The microprocessor 15 also turns OFF the timing circuit power switch 14. 
By this, those which are supplied with the power are three, i.e., the 
reference oscillator 11, the frequency dividing circuit 12, and the 
microprocessor 15. The microprocessor 15 determines the type of the frame 
by counting the frame pulses from the frequency dividing circuit 12 by the 
software in the microprocessor 15, and when the frame is a control channel 
for the wireless telephone set under consideration, the timing circuit 
power switch 14 is turned ON to operate the timing generating circuit 13, 
so as to instruct the timing generating circuit 13 to turn ON the 
transmitting-side power switch 7 and the receiving-side power switch 8. 
Thus, the microprocessor 15 controls the timing generating circuit 13 in 
accordance with the frame type of each frame. 
Since the conventional wireless telephone set is constructed as above, even 
when it is under a waiting state, it is necessary to always supervise the 
frames by software in order to receive the control channel at the 
particular frame timing. Therefore, there is a problem in that a power 
must be always supplied to the microprocessor 15 even during a waiting 
state. 
In addition, since there is no auxiliary battery in the conventional 
wireless telephone set, when the battery voltage is lowered due to 
exhaustion during a call is connected, there is a problem in that the call 
is disconnected. 
SUMMARY OF THE INVENTION 
In view of the foregoing, it is an object of the present invention to 
provide a wireless telephone set in which the power for the control 
circuit can be turned OFF during a waiting state. 
It is another object of the present invention to provide a wireless 
telephone set in which a call is not disconnected even when the battery 
voltage is lowered. 
According to the first aspect of the present invention, for achieving the 
above object, there is provided a wireless telephone set comprising 
control means for controlling the transmission and the reception of the 
signal, and a power switch for controlling the supply of a power to the 
control means. The power switch is turned ON to supply the power to the 
control means in response to each of frame signals, and is turned OFF when 
the control means judges that the wireless telephone set is in a waiting 
state for waiting a frame signal allocated to the wireless telephone set. 
As stated above, in the wireless telephone set according to the first 
aspect of the present invention, since the control means turns OFF the 
power switch after the control means judges that the wireless telephone 
set is in a waiting state for waiting a frame signal allocated to the 
wireless telephone set, the power supply to the control means in the 
waiting state is greatly reduced, and as a result, the period for the 
waiting state can be elongated. 
According to the second aspect of the present invention, there is provided 
a wireless telephone set further comprising a battery backup circuit 
switching from a battery to an auxiliary battery when the voltage of the 
battery is lowered, an auxiliary storage supplied with the power through 
the battery backup circuit for storing and holding the operating state of 
the wireless telephone set. 
As stated above, in the wireless telephone set according to the second 
aspect of the present invention, since the auxiliary storage receives the 
supply of the power from the battery back up circuit to store and hold the 
operating state of the wireless telephone set under consideration, even 
when the battery is exchanged during communication, the communication can 
be started again without disconnecting the call, once a new battery is 
mounted. 
According to the third aspect of the present invention, there is provided a 
wireless telephone set in which a timing control of the transmission and 
reception by a timing generating circuit is effected based on a frame 
pulse outputted from a frequency dividing circuit and a frame value read 
from a frame counter. 
As stated above, in the wireless telephone set according to the third 
aspect of the present invention, since the timing generating circuit 
carries out the timing control based on the frame pulse from the frequency 
dividing circuit and the frame value from the frame counter, the 
processing load of the control means is reduced. 
The above and further objects and novel features of the invention will more 
fully appear from the following detailed description when the same is read 
in connection with the accompanying drawings, It is to be expressly 
understood, however, that the drawings are for purpose of illustration 
only and are not intended as a definition of the limits of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Embodiment 1. 
In the following, an embodiment 1 of the present invention will be 
described with reference to the drawings. FIG. 2 is a block diagram 
showing an embodiment 1 of the present invention. In the figure, reference 
numeral 1 is an antenna, 2 is a duplexer, 3 is a transmitter, 4 is a 
microphone, 5 is a receiver, 6 is a speaker, 7 is a transmitting-side 
power switch, 8 is a receiving-side power switch, 9 is a battery, 10 is a 
main switch, 11 is a reference signal oscillator, 12 is a frequency 
dividing circuit, 13a is a timing generating circuit, 14 is a timing 
circuit power switch, and 15a is a microprocessor as a control circuit, 
which are the same or similar parts as the conventional parts in FIG. 1, 
and therefore, the detailed explanation is omitted here. 
Reference numeral 16 is a frame counter for counting frame pulses outputted 
from the frequency dividing circuit 12 to output frame values. Reference 
numeral 17 is a control circuit power switch for controlling the supply of 
the power from the battery 9 through the main switch 10 to the 
microprocessor 15a under consideration. The control circuit power switch 
17 is turned ON in response to each frame pulse from the frequency 
dividing circuit 12, and is turned OFF in response to a control signal 
generated by the microprocessor 15a as later described in more detail. 
Note that the microprocessor 15a controls the frequency dividing circuit 
12, the frame counter 16, the timing generating circuit 13, and so forth, 
and stops to supply the power to the microprocessor 15a itself by turning 
OFF the control circuit power switch 17 in response to a frame value 
outputted from the frame counter 16. In more detail, the microprocessor 
15a judges, based on the frame value outputted from the frame counter 16, 
whether the wireless telephone set under consideration is in a waiting 
state for waiting a frame signal allocated to the wireless telephone set 
under consideration, in a receiving state in which a frame signal 
allocated to another telephone set other than the wireless telephone set 
under consideration is being received, or in a communicating state in 
which a frame signal allocated to the wireless telephone set under 
consideration is being received and a communication is being carried out. 
The microprocessor 15a turns OFF the control circuit power switch 17 after 
the judgement of the waiting state, after the receiving state, or after 
the communicating state. 
Namely, the control circuit power switch 17 is ON only during a period 
necessary to determine whether or not the receiving signal is a frame 
signal allocated to the wireless telephone set under consideration; the 
control circuit power switch 17 is ON only during a period necessary to 
analyze the calling signal, when a calling signal directed to another 
telephone set is received or the control circuit power switch 17 is ON 
only during a period necessary to communicate when an arriving call 
directed to the wireless telephone set under consideration is received. 
Next, the operation from the turning ON of the main switch 10 to the 
waiting state in the wireless telephone set shown in FIG. 2 will be 
described with reference to a flow chart shown in FIG. 3, and time charts 
shown in FIGS. 4A to 4H. 
When the main switch 10 is turned ON (FIG. 4A), the reference signal 
generator 11, which has received the power from the battery 9 through the 
main switch 10, starts to oscillate, so that the frequency dividing 
circuit 12 divides the reference signal generated by the reference signal 
oscillator 11 to generate frame pulses having a predetermined period (FIG. 
4B). The frequency dividing circuit 12 at first runs freely without any 
relationship with the frame signals in the receiving signal. The control 
circuit power switch 17 is turned ON in response to the first frame pulse 
(step ST31, FIG. 4E), so that the microprocessor 15a is supplied with the 
power to start its operation so as to turn ON the power switch 14 for the 
timing generating circuit 13a, and to turn ON the receiving-side power 
switch 8 through the timing generating circuit 13 (steps ST32 and 33, FIG. 
4F and 4G). Then the microprocessor 15a searches base stations which are 
radiating radio waves, receives a Broadcast Control Channel (BCCH) which 
is a control signal sent from one of the base stations, and analyzes the 
BCCH to determine whether or not the received BCCH is sent from a 
contracting base station contracted with the wireless telephone set under 
consideration (steps ST34, 35, 36, and 37, FIG. 4H). Each BCCH includes a 
code for identifying the base station from which the BCCH is radiated, the 
frame number of the frame to which the BCCH belongs, and control 
information indicating to which frame each Paging Channel (Pch) directing 
to each wireless telephone set belongs. 
At step ST37, when the BCCH is not the control signal sent from the 
contracting base station, the process returns to the step ST34 to search 
base stations again. At step ST37, when it is judged that the BCCH is sent 
from a contracting base station, the wireless telephone set under 
consideration enters into a waiting state for waiting an arriving call to 
the wireless telephone set under consideration. To effect the waiting, the 
microprocessor 15a initialize the frequency dividing circuit 12 and the 
frame counter 16 (steps ST38, FIG. 4C, FIG. 4D), and turns OFF the 
receiving-side power switch 8 through the timing generating circuit 13a 
(step ST39, FIG. 4G). In the example shown in FIG. 4B, the frame signal is 
raised in response to the end of the BCCH, and, as shown in FIG. 4C, the 
value of the frame counter 16 is set to "i". This means that the BCCH is 
allocated with a frame value (i-1). 
FIG. 5A shows an example of the contents of the physical slot including the 
BCCH in the "secondary generation digital cordless telephone (PHP, 
Personal Handy Phone)", FIG. 5B shows an example of the frame pulse after 
being reset by the slot, and FIG. 5C shows the frame value after being 
reset by the BCCH. The BCCH shown in FIG. 5A consists of a rump time R for 
a transient response, a start symbol SS, a preamble PR, a synchronizing 
word UW, a Channel Identification CI, an identification code for a calling 
party, the contents I of the BCCH, a cyclic redundancy check CRC, and a 
guard. In the example shown in FIG. 5B, at 4375 .mu.s after the end of the 
BCCH, the frame pulse is reset to be raised. Also, in the example shown in 
FIG. 5C, the frame value starts from "1" because the BCCH of the PHP is 
allocated with the frame value "0". 
After the frame value is reset and after the channel type corresponding to 
the frame value is determined (FIG. 4C), the microprocessor 15a turns OFF 
the receiving-side power switch 8 through the timing generating circuit 
13a (step ST39, FIG. 4G). Then, the microprocessor 15a directly turns OFF 
the power switch 14 for the timing generating circuit 13a and the control 
circuit power switch 17 for the microprocessor 15a (steps ST40 and 41, 
FIGS. 4E and 4F). After this, the wireless telephone set under 
consideration enters into, the waiting state for waiting an arriving call, 
so that the power switch 17 for the microprocessor 15a is turned ON only 
during a predetermined short period at each time the microprocessor 15a 
receives the pulse of the frame signal from the frequency dividing circuit 
12. This predetermined short period is the time necessary and sufficient 
For judging, based on the frame value, whether or not the channel type of 
the receiving signal is the channel type allocated to the wireless 
telephone set under consideration. On the other hand, the frequency 
dividing circuit 12 continues to generate the frame pulses by dividing the 
reference signal from the reference signal oscillator 11, and the frame 
counter 16 continues to count the frame pulses. By this, those which are 
supplied with the power during the waiting state after receiving the 
control signal BCCH from the contracting base station are only three, 
i.e., the reference oscillator 11, the frequency dividing circuit 12, and 
the frame counter 16, so that the power consumption is greatly decreased 
in comparison with the conventional case in which the power is always 
supplied to the microprocessor 15. 
Next, an arriving call process in the above-mentioned waiting state will be 
described with reference to the flow chart shown in FIG. 6, the time 
charts shown in FIG. 7A to 7H, the time charts 8A to 8I, the time charts 
9A to 9C, and the time charts 10A to 10I. 
First, the operation before detecting an arriving call in the 
above-mentioned waiting state will be described with reference to the flow 
chart shown in FIG. 6 and the time charts shown in FIGS. 7A to 7H. 
The power switch 17 for the microprocessor 15a is turned ON for the 
above-mentioned short period in response to each frame pulse from the 
frequency dividing circuit 12 so that the microprocessor 15a starts to 
operate (step ST61). The microprocessor 15a which has started the 
operation at first reads the frame value from the frame counter 16 (step 
ST62), and judges, based on the frame value, whether or not the channel of 
the frame is a Paging Channel (Pch) allocated to any one of the telephone 
sets (step ST63). 
At step ST63, if the value of the frame counter 16 does not indicate the 
Pch, the microprocessor 15a turns OFF the power switch 17 for the 
microprocessor 15a, so that the wireless telephone set under consideration 
becomes the waiting state again (step ST63, ST73). 
At step ST63, if the value of the frame counter 16 indicates the Pch, the 
microprocessor 15a turns ON the power switch 14 (step ST64), turns ON the 
receiving-side power switch 8 (step ST65) through the timing generating 
circuit 13a, and receives the signal of the Pch. Then, the microprocessor 
15a judges whether or not the received Pch signal is allocated to the 
wireless telephone set under consideration (step ST67). 
In the judgement at step ST 67, if it is judged that the destination of the 
arriving call (Pch signal) is not the wireless telephone set under 
consideration but is another telephone set (FIG. 7H), the process proceeds 
to the step ST71 so that the microprocessor 15a turns OFF the 
receiving-side power switch 8 (step ST71, FIG. 7F), and then turns OFF the 
power switch 14 for the timing generating circuit 13a (step ST73, FIG 7E), 
and finally turns OFF the switch 17 for the microprocessor 15a (step ST73, 
FIG. 7D). Thus, the microprocessor 15a is returned to the waiting state 
again. 
Next, the operation to detect an arriving call to the wireless telephone 
set under consideration in the abovementioned waiting state will be 
described with reference to the steps ST 68 to 70 in FIG. 6 and FIGS. 8A 
to 8I. 
In the judgement at step ST67, when the destination of the arriving call is 
the wireless telephone set under consideration, the microprocessor 15a 
carries out a communication starting process (step ST68, FIG. 8I). Then, a 
communication is carried out by alternately turning ON the receiving-side 
power switch 8 and the transmitting-side power switch 7 (step ST69, FIGS. 
8F and 8G). When the communication is finished,-a communication ending 
process is carried out (step ST70, FIG. 8I). When the communication ending 
process is finished, the microprocessor 15a turns OFF the receiving-side 
power switch 8 and the transmitting-side power switch 7 through the timing 
generating circuit 13 (step ST71), directly turns OFF the power switch 14 
for the timing generating circuit 13a (step ST72), and directly turns OFF 
the power switch 17 for the microprocessor 15a (step ST73). Thus, the 
wireless telephone set under consideration returns to the waiting state. 
As will be apparent from the above-described operation, according to this 
embodiment 1 of the present invention, when the wireless telephone set 
under consideration is in a waiting state in which the Pch is not 
received, the power switch 17 for the microprocessor 15a is turned ON 
during a short period necessary to judge whether or not the receiving 
channel type is the Pch; and when the Pch is received, the power switch 17 
is turned ON during a period necessary to judge whether or not the Pch is 
directed to the wireless telephone set under consideration (own station). 
When the received Pch is judged to be directed to the wireless telephone 
set under consideration (own station), the power switch 17 is turned ON 
during a period from the reception of the Pch to the end of the 
communication ending process. Thus, the power conducting time for the 
microprocessor 15a is greatly shortened. 
Similarly, when the wireless telephone set under consideration is in a 
waiting state in which the Pch is not received, the power switch 14 for 
the timing generating circuit 13a is turned ON during a short period 
necessary to judge whether or not the receiving channel type is the Pch; 
and when the Pch is received, the power switch 14 is turned ON during a 
period necessary to judge whether or not the Pch is directed to the 
wireless telephone set under consideration. When the received Pch is 
judged to be directed to the wireless telephone set under consideration, 
the power switch 14 is turned ON during a period from the reception of the 
Pch to the end of the communication ending process. Thus, the power 
conducting period for the timing generating circuit 13a is also greatly 
shortened. 
FIG. 9A to FIG. 9C show the relationship among the frame pulses outputted 
from the frequency dividing circuit 12 after receiving the BCCH, the frame 
values outputted from the frame counter 16, and the channel types 
corresponding to the respective frame values, in the above-described 
embodiment. As shown in FIGS. 9A to 9C, one multiframe consists of a 
predetermined number of frame pulses corresponding to the frame values 0 
to n. Each of the frame pulses corresponds to one frame signal in the 
receiving or transmitting signal. 
In the above embodiment, the power switch 17 for the microprocessor 15a and 
the power switch 14 for the timing generating circuit 13 are always ON 
during the communication starting process as shown in FIG. 8D and 8E, 
however, it may be possible according to a modification of the above 
embodiment of the present invention to stop to supply the power to the 
microprocessor 15a and the timing generating circuit 13 after judging that 
the Pch is directed to the wireless telephone set under consideration and 
before the actual start of the control of the communication starting 
process. This modification is shown in FIG. 10A to FIG. 10I. In FIG. 8A to 
FIG. 8I and FIG. 10A to FIG. 10I, only FIG. 10D and FIG. 10E are different 
from FIG. 8D and FIG. 8E. As shown in FIG. 10D and FIG. 10E, the control 
circuit power switch 17 and the timing generating circuit power switch 14 
are OFF during times T1 and T2, namely, during a period after the 
judgement that the Pch is directed to the wireless telephone set under 
consideration and before the actual start of the control of the 
communication starting process. 
Embodiment 2. 
Next, an embodiment 2 of the present invention will be described with 
reference to FIG. 11. In FIG. 11, the corresponding parts are denoted with 
the same symbols in FIG. 2 and their explanations are omitted. In the 
figure, reference numeral 18 is an auxiliary battery for backing up the 
battery 9, and 19 is a battery back up circuit for switching to the 
auxiliary battery 18 when the voltage of the battery 9 is lowered or when 
the battery 9 is removed. Reference numeral 20 is a back up power switch, 
which interlocks with the main switch 10 to operate, for supplying the 
power from the battery 9 or the auxiliary battery 18, which is switched by 
the battery back up circuit 19, to the reference signal oscillator 11, the 
frequency dividing circuit 12, and the frame counter 16. Reference numeral 
21 is an auxiliary storage for receiving the power supply through the back 
up power switch 20 to store and hold the operating state of the wireless 
telephone set under consideration. 
Next, the operation will be described. Here, since the basic operation is 
the same as that in the embodiment 1, its explanation is omitted. When the 
main switch 10 is turned ON, the backup power switch 20 is also turned ON 
so that the reference frequency oscillator 11, the frequency dividing 
circuit 12, and the frame counter 16 are supplied with a power from the 
battery 9. The microprocessor 15a sends the operating state of the 
wireless telephone set under consideration each time it receives a frame 
signal to the auxiliary storage 21 to store and hold it therein. When the 
voltage of the battery 9 is lowered due to exhaustion during a 
communication, the battery back up circuit 19 switches from the power 
supplied from the battery 9 to the one from the auxiliary battery 18. 
Whereby, the reference signal oscillator 11, the frequency dividing 
circuit 12, and the frame counter 16 continue to operate normally, and the 
auxiliary storage 21 continues to hold the operating state of the wireless 
telephone set under consideration at that time. Accordingly, even when the 
battery 9 is removed to be exchanged, the call is not cut although the 
communication is cut, and once a new battery 9 is again mounted, the 
communication can be started again. 
According to a modification of the above embodiment 2, the battery backup 
power switch 20 may be removed. In this case, the output of the battery 
backup circuit 19 is directly connected to the reference frequency 
oscillator 11, the frequency dividing circuit 12, the frame counter 16, 
and the auxiliary storage 21 so that these elements are supplied with the 
power even when the main switch 10 is in an OFF state. 
Further, according to another modification of the embodiment 2, instead of 
providing the auxiliary storage 21, the microprocessor 15a may store the 
operating state of the wireless telephone set under consideration each 
time it receives a frame signal. By this, the auxiliary storage 21 is not 
necessary. 
Embodiment 3. 
In the above-described embodiments, an explanation was given for the case 
in which the control of the timing of the transmission and the reception 
by the timing generating circuit 13a is carried out based on the frame 
pulses outputted from the frequency dividing circuit 12, it can also be 
carried out based on both of the frame pulses read from the frequency 
dividing circuit 12 and the frame values read from the frame counter 16. 
FIG. 12 is a block diagram showing this embodiment 3 of the present 
invention, in which each part is denoted by the same or similar symbol for 
the corresponding part in FIG. 2, and the explanation thereof is omitted. 
The embodiment shown in FIG. 12 is different from the one shown in FIG. 2 
in that the frame value from the frame counter 16 is inputted into a 
timing generating circuit 13b and a microprocessor 15b does not receive 
the frame value from the frame counter 16. 
Thus, by inputting the frame value counted by the frame counter 16, the 
timing generating circuit 13b determines by itself the frame, so that the 
transmitter 3, the receiver 5, the transmitting-side power switch 7, and 
the receiving-side power switch 8 can be controlled with a reduction of 
the intervention of the microprocessor 15b. Therefore, the processing load 
of the microprocessor 15b can be largely reduced. 
Embodiment 4. 
In the above embodiment 2, the battery back up system is included in the 
wireless telephone set of the first embodiment 1, however, according to an 
embodiment 4, the battery back up system may also be applied to the 
conventional wireless telephone set shown in FIG. 1. FIG. 13 is a block 
diagram showing the wireless telephone set according to the embodiment 4. 
In FIG. 13, a microprocessor 15c always stores the operating state of the 
wireless telephone set under consideration each time it receives a frame 
signal. The auxiliary battery 18 and the battery backup circuit 19 are 
provided in the conventional wireless telephone set shown in FIG. 1. The 
output of the battery backup circuit 19 is connected through the backup 
power switch 20 to the reference frequency oscillator 11, to the frequency 
dividing circuit 12, to the frame counter 16, and to the microprocessor 
15C. 
Next, the operation will be described. Here, since the basic operation is 
the same as that in the conventional wireless telephone set, its 
explanation is omitted. When the voltage of the battery 9 is lowered due 
to exhaustion during a communication, the battery back up circuit 19 
switches from the power supplied from the battery 9 to the one from the 
auxiliary battery 18. Whereby, the reference signal oscillator 11, the 
frequency dividing circuit 12, the frame counter 16, and the 
microprocessor 15c continue to operate normally. Accordingly, even when 
the voltage of the battery 9 is lowered, the call is not disconnected 
because the microprocessor 15c stores the operating state when the 
communication is interrupted, and once a new battery 9 is again mounted, 
the communication can be started again. 
Similar to the embodiment 2, in the above embodiment 4, the battery backup 
power switch 20 may be removed according to a modification of the 
embodiment 4. In this case, the output of the battery backup circuit 19 is 
directly connected to the reference frequency oscillator 11, the frequency 
dividing circuit 12, the frame counter 16, and the auxiliary storage 21 
(which is shown in embodiment 2 and, for the modification of embodiment 4 
being referred to, would become an element of embodiment 4 and be 
connected in FIG. 13 in the same manner as shown in FIG. 11 for embodiment 
2) so that these elements are supplied with the power even when the main 
switch 10 is in an OFF state. 
Embodiment 5 
In the above embodiment 4, the microprocessor 15c stores the operating 
state of the wireless telephone set under consideration, however, similar 
to the embodiment 2 shown in FIG. 11, the auxiliary storage 21 may be 
provided to store the operating state of the wireless telephone set under 
consideration, as shown in FIG. 14. In FIG. 14, the auxiliary battery 18, 
the battery backup circuit 19, and the auxiliary storage 21 are provided 
in the conventional wireless telephone set shown in FIG. 1. The output of 
the battery backup circuit 19 is connected through the backup power switch 
20 to the reference frequency oscillator 11, to the frequency dividing 
circuit 12, to the frame counter 16, and to the auxiliary storage 21. 
Next, the operation will be described. Here, since the basic operation is 
the same as that in the conventional wireless telephone set, its 
explanation is omitted. When the voltage of the battery 9 is lowered due 
to exhaustion during a communication, the battery back up circuit 19 
switches from the power supplied from the battery 9 to the one from the 
auxiliary battery 18. Whereby, the reference signal oscillator 11, the 
frequency dividing circuit 12, the frame counter 16, and the auxiliary 
storage 21 continue to operate normally. Accordingly, even when the 
voltage of the battery 9 is lowered, the call is not disconnected, and 
once a new battery 9 is again mounted, the communication can be started 
again. 
Similar to the embodiment 4, in the above embodiment 5, the battery backup 
power switch 20 may be removed according to a modification of the 
embodiment 5. 
The present invention is not restricted to the above-described embodiments, 
but various changes and modifications are possible without departing from 
the spirit of the present invention. 
As described above, in the wireless telephone set according to the first 
aspect of the present invention, since the control means turns OFF the 
power switch for the control means after any one of the following three 
states, namely, after the control means judges that the wireless telephone 
set is in a waiting state for waiting a frame signal allocated to the 
wireless telephone set, after the control means judges that in a first 
receiving state in which a frame signal allocated to another telephone set 
is being received, and after the control means judges that a communication 
ending process is finished in a second receiving state in which a frame 
signal allocated to the wireless telephone set under consideration is 
received, the power to the control means in the waiting state for waiting 
an arriving call is greatly reduced. 
Also, according to the second aspect of the present invention, since the 
operating state of the wireless telephone set under consideration is 
stored and held in an auxiliary storage for receiving the power through a 
battery back up circuit and a back up power switch, there is an effect in 
that even when the battery is exchanged during communication, the call is 
not disconnected, and once a battery is again mounted, the communication 
can be started again. 
Further, according to the third aspect of the present invention, since the 
timing generating circuit carries out the timing control based on the 
frame pulse from the frequency dividing circuit and the frame value from 
the frame counter, the processing load of the control circuit can be 
largely reduced.