JP3133901B2 - Digital cordless telephone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital cordless telephone capable of making a direct simultaneous call between a plurality of slave units.

[0002]

2. Description of the Related Art Conventionally, a digital cordless telephone has a base station (PS) connected to an exchange via a telephone line,
It comprises a plurality of wireless slaves (CS), and as a wireless transmission and reception system between the master and the slaves, a TDMA / TDD system (Time
Division Multipie Access / Time Division Duplex)
For such a digital cordless telephone, a standard has been established at the Radio System Development Center, and the final draft is "RCR STD-2".
8 "has been approved. And this standard "RCR
TDMA / TDD defined by "STD-28"
In the system, one frame is composed of a plurality of transmission slots and the same number of reception slots, and each transmission slot is associated with a reception slot, and transmission / reception is performed by a combination of the transmission slot and the reception slot. That is, since transmission and reception are performed in a transmission slot and a reception slot with time separation, the transmission frequency and the reception frequency can be the same frequency, and a plurality of transmissions and receptions can be performed at one frequency. .

In such a digital cordless telephone, as described in Japanese Patent Application Laid-Open No. 4-213933, a one-way direct call between a plurality of slaves at a single frequency without passing through a master. In such a digital cordless telephone, a vacant channel is captured based on a one-way simultaneous call mode detection signal from a one-way simultaneous call mode detection means, and a child including information of the call channel is acquired. After the direct simultaneous connection request signal between the devices is sent directly to the other handset, a synchronization signal for setting a transmission / reception slot is sent out to the other handset. Then, by setting a communication channel and a transmission / reception slot for direct simultaneous communication between the unidirectional slaves from the information in the partner handset, transmission slots and reception slots that are temporally different from each other are set. A simultaneous simultaneous call between the slave units can be performed at the transmission / reception frequency.

In this state, by turning on a press-talk switch provided in each slave unit, a voice message input from a microphone of the slave unit which has been turned on is transmitted to a partner slave unit in a predetermined transmission slot. In the other handset, when the transmission is performed in the predetermined transmission slot, the voice message is in the reception slot, so that the voice message input after the press-talk switch is turned on is received and emitted from the speaker. Therefore, by directing the press-talk switch on and off with the respective mobile units shifted in time, direct communication between the mobile units can be performed between three or more mobile units by the unidirectional simultaneous call system. Was configured as follows.

[0005]

However, in the above-mentioned conventional apparatus, in order to actually perform the direct simultaneous communication between the one-way slaves, it becomes possible to perform the direct simultaneous communication between the slaves at one transmission / reception frequency. However, it is necessary to manually turn on and off the press-talk switch by manual operation when it is desired to speak in each slave unit, and the on-off operation is cumbersome, and the press-talk switch is turned on and off. Manually changes the caller, there is the danger that the Pre-Stoke switch will be turned on at the same time at each child device, and if the Pre-Talk switch is turned on at the same time at each child device, interference will occur. And the call can no longer be made.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a digital cordless telephone capable of talking with another slave without manual operation in direct simultaneous communication between slaves.

[0007]

In order to achieve the above object, an invention according to claim 1 comprises a master unit and a plurality of slave units, and performs a call by making transmission and reception different in time. In a digital cordless telephone capable of making direct simultaneous calls between child devices between a plurality of child devices, the number of child devices performing direct general calls between child devices is set for each child device, and for each child device, Slave unit number setting means for assigning different slave unit numbers, and transmission / reception timing setting means for setting transmission / reception timing of the own station in an idle state based on the slave unit number and the slave unit number set by the slave unit number setting unit When,
Voice input detection means for detecting the presence / absence of sound input to the microphone, and a detection signal from the voice input detection means including a slave unit number of the own station, and a detection including the slave unit number of the own station Detection signal sending means for sending a signal to another slave based on the timing set by the transmission / reception timing setting means; and, when the detection signal is received, the received detection signal, slave number included in the detection signal And a synchronization establishing means for synchronizing transmission and reception in a call state based on the transmission and reception timing set by the transmission and reception timing setting means, and shifting to a transmission operation at a transmission timing of the own station after the synchronization is established by the synchronization establishing means, At this time, a transmitting means for transmitting the sound input to the microphone to another slave, and a receiving station of the own station after the synchronization is established by the synchronization establishing means. Receiving means that shifts to a receiving operation in a timing, and, when an audio signal is received by the receiving means, a transmission source slave unit is set based on the reception timing of the audio signal and the transmission / reception timing set by the transmission / reception timing setting means. with determining, when the transmission timing of its own station in an idle state and transmission timing in the call state of the transmission Motoko machine matches, the feed
It said to also shift to the reception operation in the signal timing
And a control unit for controlling the transmission unit and the reception unit.

According to a second aspect of the present invention, the control means includes:
When the transmission timing of the own station in the idle state is different from the transmission timing of the voice terminal transmitting apparatus in the talking state, the detection signal including the own station's slave number is transmitted to the other slave in the transmission timing of the own station in the idle state. Is sent to the machine.

According to a third aspect of the present invention, each of the slave units is identified by a common identification code, and only the slave units having the same identification code can establish the communication state synchronization by the synchronization establishing means. Is what is done.

According to a fourth aspect of the present invention, there is provided an operation input means for inputting a handset number of a handset desired to perform a direct simultaneous call between handset units, and detecting the handset number inputted by the operation input means as the audio signal detection. Means for assigning a call designation included in the detection signal from the means, and a call designation slave unit for comparing, when receiving the detection signal, the call designation slave unit number included in the received detection signal with the slave unit number of the own station. Number control means is provided, and only when it is determined that the specified telephone number matches based on the result of comparison by the specified telephone number comparing means, the specified telephone number matches. The synchronization establishing means is controlled so as to synchronize transmission and reception in a call state based on the detection signal and the transmission and reception timing set by the transmission and reception timing setting means.

According to a fifth aspect of the present invention, when it is determined based on the result of comparison by the designated telephone unit number comparing means that the designated telephone unit number matches, a detection signal indicating that the telephone designated child unit number coincides. Is provided with a display means for displaying the slave unit number included in.

According to a sixth aspect of the present invention, when the call designation assigning means determines that the call designation slave unit numbers match based on the comparison result by the call designation slave unit number comparison means, the call designation identifier is determined. The slave unit number included in the detection signal having the matched unit number is included in the detection signal from the voice signal detecting means as a call designation slave unit number.

[0013]

Therefore, according to the first aspect of the present invention, the number of sub-units performing direct simultaneous communication between sub-units in advance by operation input by the sub-unit number input means in each sub-unit and the sub-units differing from each other By setting the number, the transmission / reception timing setting means sets the transmission / reception timing of the own station in the idle state. Then, at the time of starting the direct simultaneous call between the slave units, the detection signal sending unit includes the slave unit number of the own station in the detection signal from the voice input detection unit and sends it to the other slave units, and the detection signal and the idle state Establishes synchronization by synchronizing transmission / reception in a call state based on the transmission / reception timing of the own station at the same time, and when the above-described detection signal is also received at another slave unit, the received detection signal and each slave unit Synchronization is established by synchronizing transmission and reception in the call state based on the transmission and reception timing of the own station in the idle state of the apparatus. And, depending on the receiving means
Audio signal is received, and the caller's
Transmission timing and own station transmission in idle state
When the timing coincides, the control means sends the transmission means and
And the receiving means is controlled so as to shift to the receiving operation even at the transmission timing, so that a voice message is input to the microphone to automatically shift to a talking state, and direct communication between the slave units. Simultaneous communication can be performed, and interference between radio waves in a communication state can be prevented, so that communication can be performed satisfactorily.

According to the second aspect of the present invention, the transmission timing of the own station in the idle state and the transmission of the source slave unit to which the voice signal is transmitted in the idle state by the control means after the synchronization of transmission and reception in the telephone call state is established. If it is determined that the timing is different, the detection signal transmitting means is controlled to transmit a detection signal including the slave unit number of the own station to the other slave unit at the transmission timing of the own station in the idle state, so that the idle state is controlled. , Transmission and reception timing can be secured.

According to the third aspect of the present invention, each slave unit is identified by a common identification code, and synchronization is established by the synchronization establishing means only between the slave units having the same identification code, and the communication state is established. By doing so, it is possible to restrict the selection of a slave unit that performs direct simultaneous communication between slave units.

According to the fourth aspect of the present invention, at the time of starting the direct simultaneous call between the slave units, the slave unit number of the slave unit to which the direct simultaneous talk between the slave units is to be set by the operation input by the operation input means, The call designation providing means includes the set slave unit number in the detection signal. Then, at the time of activation of the direct simultaneous call between the slave units, when each of the slave units receives a detection signal including the call designation slave unit number, the call designation slave unit number comparison unit outputs the call designation included in the received detection signal. The control unit compares the unit number with the slave unit number of the own station, and controls the synchronization establishing unit only when the control unit determines that the slave unit number matches based on the comparison result to establish synchronization of transmission and reception in a call state. By doing so, it is possible to arbitrarily select and regulate a slave unit that allows direct simultaneous communication between slave units.

According to the fifth aspect of the present invention, when the direct simultaneous call between the slave units is activated, each of the slave units receives a detection signal including the call designation slave unit number, and Based on the comparison result by the comparing means, when the control means determines that the call designation slave unit number included in the received detection signal and the slave unit number of the own station match, the display means includes the slave terminal number in the received detection signal. By displaying the slave unit number to be displayed, it is possible to easily determine from which slave unit the designated call request has been received.

According to the sixth aspect of the present invention, when a direct simultaneous call between slave units is started, each slave unit receives a detection signal including a call designation slave unit number, and When the control means determines, based on the result of the comparison by the comparing means, that the call designation slave unit number included in the received detection signal matches the slave unit number of the own station, the call designation giving means detects the received detection signal. Is included in the detection signal transmitted from the own station as the designated telephone number of the telephone set included in the terminal, so that even when the mobile terminal returns to the idle state, the telephone call with the telephone unit for which the specified telephone call request is continuously made can be made. It can be performed.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a slave unit in a digital cordless telephone according to an embodiment of the present invention. FIG. 2 is a timing chart showing transmission / reception timings of each slave unit in an idle state in the digital cordless telephone. FIGS. 3 and 4 are timing charts showing transmission / reception timings in a call state of each slave unit in the digital cordless telephone. FIGS. 5 to 7 are flowcharts showing operation control of direct simultaneous communication between slave units in the digital cordless telephone. .

In FIG. 1, 1 is a microphone as a transmitter, 2 is a speaker as a receiver, and 3 is an analog voice input to the microphone 1 according to μ-1aw.
Sampling at kHz / 8 bits, converting to 64 kbps digital data and inputting 64 kbps
The PCM codec unit that decodes the digital data into an analog signal and outputs the analog signal to the loudspeaker, the VOX 4 determines that there is no sound when the digital data converted by the PCM codec unit 3 is lower than a certain set level, and separately outputs a VOX signal. It is a determination circuit.

Reference numeral 5 denotes digital data input through the VOX determination circuit 4 according to CCITT (current ITU-TS). Data compression is performed according to the R.721 rule, the data is converted into digital data of 32 kbps, and the input 32 kbps.
The ADPCM codec unit 6 for expanding the digital data of s and decoding it to digital data of 64 kbps.
An additional signal is added to the digital data of 2 kbps and various control data to create a signal format having a frame configuration in accordance with RCR-STD28, which is compressed to a signal of 384 kbps, and the data of the input 384 kbps is expanded to 38 kbps. This is a channel codec unit that decodes and simultaneously analyzes the type of signal to determine whether it is a control signal, a voice signal, or a VOX signal.

Reference numeral 7 designates a phase change amount to be selected from ± π / 4 and ± 3π / 4 in accordance with a signal transmitted every two bits.
An RF unit for performing digital modulation according to a 4-shift QPSK modulation method.
The bps signal is modulated to a frequency in the 1.9 GHz band, and the received 1.9 GHz signal is demodulated to a 384 kbps signal. Reference numeral 8 denotes a transmission / reception switch for switching between the transmission unit and the reception unit based on the transmission timing and the reception timing of the own station. Reference numeral 9 denotes an antenna for transmitting and receiving signals.

Numeral 10 is a numeric keypad for inputting the other party's telephone number.
An operation input unit 11 including an external call button for shifting to an external call mode, a direct simultaneous call button for a slave unit for shifting to a slave unit number registration mode and a direct simultaneous call mode between slave units, and a send button for making a call connection in each mode; Is a display unit for performing a display based on the information input and received by the operation input unit 10 and 12 is a VOX signal from the VOX determination circuit 4, a control signal and a VOX signal analyzed by the channel codec unit 6, and an operation. A control unit that performs various controls based on an operation input signal from the input unit 10 and controls a communication protocol.

A direct simultaneous call between slave units in the slave unit of the digital cordless telephone configured as described above will be described. In this embodiment, a case will be described in which the number of slave units performing direct simultaneous communication between slave units is four.

When the direct simultaneous call button between the handset units of the operation input unit 10 is operated in advance in each of the handset units that perform the direct simultaneous call between the handset units, the mode is first shifted to the handset number registration mode.
While confirming the contents displayed on the display unit 11 in the slave unit number registration mode, input the number of the slave unit and the slave unit number of the own station by directly operating the ten-key which inputs the other party's telephone number. I do. In the case of the present embodiment, since the simultaneous call is directly performed between the slave units by using four units, "4" is operated and input, and then "1", "2", "3", ""
4 "is selected and input so that it does not overlap with the slave unit number of the slave unit of another station.

When the number of slave units performing direct simultaneous communication between the slave units and the slave unit number of the own station are input, the control unit 12 recognizes the number of frames used for the direct simultaneous communication between the slave units, and sets the other slave units together. The transmission timing in the idle state of the own station after the establishment of the synchronization with the local station is set.

That is, in the idle state and the call state, 5
msec (one frame) is divided into eight, and the first four are allocated to transmission slots and the last four are allocated to reception slots.
The first transmission slot and the fifth reception slot, the second transmission slot and the sixth reception slot, the third transmission slot and the seventh reception slot, and the fourth transmission slot and the eighth reception slot are each one pair. In this case, the operation input unit 1
Since "4" is operated and input by "0", as shown in FIG. 2, two frames are used as one unit, which are sequentially recognized as the 1st to 16th frames, and "1" is operated as the slave unit number. When input, the first slot in an idle channel is set as the transmission timing of the own station, for example, as the transmission timing in the idle state after the synchronization is established, and the fifth, ninth, and thirteenth slots are set as the reception timing. I do.

When the slave unit number "2" is operated and input, the fifth slave unit having the slave unit number "1" at the reception timing as the transmission timing of the own station in the idle state after the synchronization is established. The slot is set, and the slave unit having the slave unit number "1" as the reception timing sets the first slot and the ninth and thirteenth slots at the transmission timing, and "3" is operated and input as the slave unit number. In the idle state after the synchronization is established, the ninth slot in which the slaves with the slave numbers "1" and "2" are in the reception timing is set as the transmission timing of the own station in the idle state after the synchronization is established, and the slave number " The slave units 1 "and" 2 "set the first and fifth slots and the thirteenth slot at the transmission timing, and" 4 "is operated as the slave unit number. In the idle state after the synchronization is established, the slaves with slave numbers "1", "2", and "3" set the 13th slot at the reception timing as the transmission timing of the own station in the idle state after the synchronization is established. The first, fifth, and ninth slots at which the slaves with the slave numbers "1", "2", and "3" are at the transmission timing are set.

Therefore, in the idle state after the synchronization is established, when the slave with the slave number "1" is in the transmission state, the slaves with the other slave numbers "2", "3" and "4" are in the reception state. When the slave unit with the slave unit number "2" is in the transmission state, the slave units with the other slave unit numbers "1", "3" and "4" are in the reception state, and the slave unit with the slave unit number "3". When the slave unit is in the transmission state, the slave units with the other slave numbers "1", "2" and "4" are in the reception state, and when the slave unit with the slave number "4" is in the transmission state, the other slave units are in the other state. The slave units of the slave unit numbers "1", "2" and "3" are in the receiving state, and the VOXs do not interfere with each other.
Signals can be transmitted and received.

The transmission timing of the slave unit having the slave number "1" is the first slot and the reception timing is the fifth slot. However, the present invention is not limited to this.
The third, fourth, and fourth slots may be used as the transmission timing, and the sixth, seventh, and eighth slots may be used as the reception timing. At this time, the slaves with the slave numbers "2", "3", and "4" The transmission / reception timing is set with reference to the transmission / reception timing set in the child device of the child device number “1”.

Then, in the slave unit number registration mode, the operation input unit 10 inputs the number of slave units and the respective slave unit numbers for direct simultaneous communication between the slave units, and the control unit 12 controls each slave unit in the idle state after synchronization is established. When the timing of transmission / reception of the device is set, it becomes direct simultaneous call mode between child devices,
When the transmission button of the operation input unit 10 is operated in each of the slave units in the direct simultaneous call mode between the slave units, the slave units are synchronized with each other and are shifted to the idle state.

The operation for shifting to the idle state is as follows.
For example, the case where the transmission button of the operation input unit 10 of the slave unit with the slave unit number “1” is operated first will be described. When the transmission button of the operation input unit 10 of the slave unit number "1" is operated, the slave unit of the slave unit number "1" performs carrier sense on the communication carrier, and the reception slot section (section of one slot) is set. When it is confirmed that the slot can be used (vacant) for four or more consecutive frames, the corresponding slot is set as a reference transmission timing in direct simultaneous communication between slave units.

Then, in the slave unit having the slave unit number "1",
The VOX determination circuit 4 outputs to the control unit 12 a VOX signal that is output when it is determined that the audio signal from the microphone 1 digitally converted by the PCM codec unit 3 is lower than a predetermined level and is silent. After the VOX signal output from the VOX determination circuit 4 includes the slave unit number “1” of the own station, the channel codec unit 6
Output. Then, an additional signal is added to the VOX signal in the channel codec section 6 to create a predetermined signal format and compress the signal format.
The F unit 7 performs digital modulation by a π / 4 shift QPSK modulation method to perform modulation to a frequency of 1.9 GHz band,
The control unit 12 controls the transmission / reception switch 8 so that the VOX signal modulated by the RF unit 7 is transmitted from the antenna 9 at the timing of the corresponding slot.

Then, the slave unit numbers "2", "3" and "
When the VOX signal transmitted from the slave unit having the slave unit number "1" is received by the antenna 9 by scanning all the channels of the communication carrier in the slave unit 4 ", the received VOX signal is transmitted to the transmission / reception switch 8 Via RF
After being input to the demodulation unit 7 and demodulated, it is output to the channel codec unit 6. The channel codec unit 6 decompresses and decodes the input VOX signal, and judges that the VOX signal is a VOX signal. Output.
The control unit 12 selects the frequency and transmission timing of the radio wave transmitted by the own station based on the VOX signal, the slave unit number “1” included in the VOX signal, and the transmission / reception timing in the idle state of the own station.

In this state, the slave unit number "2", "
When the transmission button of the operation input unit 10 is operated in each of the slave units 3 ”and“ 4 ”, the VOX signal of the own station is transmitted by the same operation as that of the slave unit with the slave unit number“ 1 ”at the selected frequency and transmission timing. Then, synchronization is established between the slave unit “1” and the slave unit that has operated the transmission button, and a transition is made to the idle state.

In this embodiment, the case where the transmission button of the slave unit having the slave unit number "1" is first operated as the operation for shifting to the idle state has been described. However, the present invention is not limited to this. The slave unit numbers "2", "3" and "4"
By operating any one of the transmission buttons of the slave unit, it is possible to similarly shift to the idle state. The operation at this time is as follows. First, the slave unit whose transmission button is operated performs the carrier sense similarly to the operation of the slave unit of the slave unit number “1” described above, confirms the available channel and slot, and determines the corresponding slot. A VOX signal is set and transmitted as a reference transmission timing in a direct simultaneous call between slave units, and the VOX signal is received by another slave unit. Synchronization and transition to the idle state are possible.

In the idle state after the synchronization is established, for example, when a voice message is input to the microphone 1 of the slave unit having the slave number "1", the analog voice message input to the microphone 1 is converted to the PCM.
After being converted to digital data by the codec unit 3, the digital data is input to the VOX determination circuit 3, where the input digital data is higher than the set level, and it is determined that the input from the microphone 1 is sound, and the determination is made. The result is output to the control unit 12, and the control unit 12 controls the transmission / reception switch based on the determination result so that the transmission unit is switched to the transmission unit system at the transmission timing of the own station in the idle state and the own station in the idle state. VO at the transmission timing (the first slot shown in FIG. 2)
After transmitting a signal different from the X signal, the mobile station shifts to the talk state, and then sets the transmission / reception switch to switch to the transmitting section at the transmission timing (the first and ninth slots shown in FIG. 3) in the talk state. Control.

On the other hand, the audio data input to the VOX determination circuit 4 is input to the ADPCM codec unit 5, where predetermined data compression is performed, and
Output. The channel codec section 6 adds an additional signal to the data-compressed audio digital data to create a predetermined signal format and compresses the signal. The RF audio section 7 converts the compressed audio digital data into a π / 4 shift Q
1.9G by performing digital modulation by PSK modulation method
The frequency is modulated to the frequency in the Hz band, and the control unit 12 controls the transmission / reception changeover switch 8 so that the transmission timing of the own station in the idle state (the first slot shown in FIG. 2) is used.
The audio digital data modulated by the unit 7 is transmitted from the antenna 9 and the transmission timing of the own station in the call state (the first and ninth slots shown in FIG. 3) is set to R
The digital audio data modulated by the F unit 7 is transmitted.

The slave unit numbers "2", "3" and "
Since the slave unit of the slave unit No. 4 is the reception timing in the idle timing of the slave unit of the slave unit number “1”, the audio digital data transmitted from the slave unit of the slave unit number “1” is received by the antenna 9 The received audio digital data is transmitted to the
After being input to the F unit 7 and demodulated, the data is output to the channel codec unit 6. The channel codec unit 6 decompresses and decodes the input audio digital data and judges that the input audio digital data is audio data. 5 is output. The ADPCM codec unit 5 decompresses and decodes the input audio digital data, and
The voice digital data is input to the PCM codec unit 3 via the X determination circuit 4, the input digital audio data is decoded into an analog signal, and then output to the speaker 2 for sound emission to the outside.

On the other hand, slave unit numbers "2", "3" and "4"
The channel codec unit 6 determines that the transmission signal received from the slave unit with the slave unit number “1” is not a VOX signal but audio data, and the control unit 12 controls the slave unit with the slave unit number “1”. When it is determined that the handset has shifted to the talking state, it is determined whether or not the transmission timing of the handset with the handset number “1” in the talking state matches the transmission timing of the own station in the idle state.

As a method for this determination, the slave unit number of the slave unit whose transmission timing of the slave unit number "n" in the talking state matches the transmission timing of the slave unit in the idle state is "n ±".
It is determined from the fact that the natural number is an even number and the result of the calculation is a natural number. That is, the transmission timing of the slave unit of the slave unit number "1" in the call state matches the transmission timing of the own station in the idle state. The slave unit number of the slave unit to be executed is “1 ± even number of natural numbers” and the calculation result is a natural number, so “3”, “5”, “7”
.., And the number of slave units for which the call is set is “4”, so that the slave units whose transmission timings match are “4” or less, and thus the slave units of the slave unit number “3” satisfying all the conditions. The transmission timing in the idle state of the slave unit number is
It is determined that the transmission timing coincides with the transmission timing in the call state of the slave unit of “1”.

According to this determination method, the control unit 12 of the slave unit with the slave unit number "3" determines that the transmission timing of the own station in the idle state is equal to the transmission timing of the slave unit with the slave unit number "1" in the talking state. If it is determined that they match, the transmission / reception changeover switch 8 is controlled to switch to the reception unit even at the transmission timing of the own station in the idle state, while the control units of the child units of the child unit numbers “2” and “4” are controlled. 12 determines that the transmission timing of the own station in the idle state does not match the transmission timing of the slave unit with the slave unit number "1" in the talking state, and controls the transmission / reception switch 8 to control the transmission timing of the own station in the idle state. Control is performed to switch to the transmission system, and the VOX signal of the own station is transmitted at the transmission timing of the own station in the same manner as in the idle state. Make.

In this state, if a voice message is continuously input to the microphone 1 of the slave unit with the slave unit number "1", the slave unit with the slave unit number "1" has shifted to the talking state. The digital audio data is transmitted from the slave unit having the unit number “1” at the transmission timing of the slave unit number “1” in the call state, and the slave unit numbers “2”, “3” and “4” are assigned to the slave unit numbers. When the slave unit of "1" is received at the transmission timing because of the reception timing, the slave unit of the slave unit number "1" is in a call transmission state.

When the input of the voice message to the microphone 1 of the slave unit of the slave unit number "1" is completed in the call transmission state of the slave unit of the slave unit number "1", the PCM codec unit in the VOX determination circuit 4 It is determined that the audio signal from the microphone 1 that has been digitally converted by the microphone 3 is lower than a predetermined level and is silent, and a VOX signal indicating silence is output to the control unit 12. The control unit 12 shifts to the idle state based on the VOX signal from the VOX determination circuit 4 and adds the slave unit number “1” of the own station to the VOX signal.
Is transmitted, and transmission is performed by the same operation as the above transmission operation.

Then, the slave unit numbers "2", "3" and "
When the VOX signal transmitted from the slave unit having the slave unit number "1" in the slave unit 4 "is received by the same operation as the above-described receiving operation and input to the control unit 12, the slave unit is shifted to the idle state. Similar to the operation in the idle state after the synchronization is established, the VOX of the own station is transmitted at the transmission timing of the own station.
Send a signal.

When a voice message is input to the microphone 1 of the slave unit having the slave unit number "2" in the idle state after the establishment of the synchronization, the slave unit number "1" is input.
As in the case of the slave unit, audio digital data is transmitted at the transmission timing in the idle state of the own station, and the slave units of the slave unit numbers "1", "3" and "4" are the slave units of the slave unit number "2". shifts to a call state by receiving audio digital data from the machine, (5 th and 1 third slot depicted in FIG. 4) audio in a digital transmission timing in a call state of the handset subsequent handset number "2" The data is transmitted and received by the slaves with the slave numbers "1", "3", and "4", so that a call is performed. Thereafter, the above operation is repeated to perform a direct simultaneous call between the slaves. .

When the transmission button (or the end button) of the operation input unit 10 is operated in the idle state or the call state after the establishment of the synchronization, the operated slave unit is turned on in the idle state or the call state. The power supply to each block to be supplied is cut off, the call ends, and a transition is made to a normal standby state. Since the slave unit that ended the call scans all channels of the communication carrier in the normal standby state, it is necessary to perform a direct simultaneous call between the slave units between the other slave units that have been set in advance. Receives the VOX signal from each slave unit,
The control unit 12 selects the frequency and the transmission timing of the radio wave transmitted by the own station by receiving the OX signal. Therefore, if the transmission button is operated again, the direct simultaneous communication between the sub-units between the sub-units set in advance is resumed. You can participate.

Also, in the case where the call is terminated at each slave unit and the direct simultaneous talk between the slave units is not performed between the preset slave units, the direct simultaneous talk mode between the slave units is released and another mode is set. By operating the transmission button in each slave unit, a carrier scan is performed on the slave unit on which the transmission button is operated to check an available channel and a slot, unless the mode is shifted to an outside line communication mode, for example. The corresponding slot is set as a reference transmission timing in the direct simultaneous communication between the slave units, and the VOX signal is transmitted. When the VOX signal is received in another slave unit and the transmission button is operated, the transmission is performed. Simultaneous calls can be made directly between the slave units whose buttons have been operated.

[0049] As described above will be described with reference to a flowchart shown in FIGS. 5 and 6, the operation control of the slave unit at the time when simultaneous call button between handset direct manipulation input unit 10 is operated. The flowchart shown in FIG. 5 shows the operation control of the child device in the child device number registration mode, and the flowchart shown in FIG. 6 shows the operation control of the child device in the direct communication mode between the child devices.

First, the operation control of the slave unit in the slave unit number registration mode will be described with reference to the flowchart shown in FIG. When the simultaneous call button between the slave units of the operation input unit 10 is operated, the slave unit number registration mode is set,
This flowchart is started, and the process proceeds to step F1. In step F1, the display unit 11 is controlled to display, for example, "Please input the number of slave units of the slave unit performing direct simultaneous communication between slave units." A request for inputting the number of slave units is made, and the process proceeds to step F2.
In step F2, the numerical value input by the operation input unit 10 is input as "Xn", and the process proceeds to step F3.

In step F3, the display unit 11 is controlled to display, for example, "Please input the slave unit number of the own station so as not to overlap with the slave unit number of another station." A request is made to input a number, and the process proceeds to step F4.
o ", and the flow shifts to step F5.

In step F5, it is determined whether or not the number of slave units "Xn" input in step F2 is equal to or greater than the number of slave units "No" input in step F4, and the number of slave units "Xn" is determined. If it is determined that the value matches or is larger than the slave unit number “No”, the process proceeds to step F
5 and when it is determined that the number of slaves “Xn” is smaller than the number of slaves “No”, the number of slaves “Xn” and the number of slaves “No” input by the operation input unit 10 are input. Is determined to be incorrect (error), the process proceeds to step F1, and the above operation is repeated. Note that the determination result may be displayed on the display unit 11.

In step F6, initial settings for performing the calculation formula are performed, "@" used in the calculation formula is set to "all natural numbers of Xn to 1", and the process proceeds to step F7. In step F7, the input is performed in step F2. Number of slave units "Xn"
Is determined to be an even number, and when it is determined not to be an even number, the process proceeds to step F8, where a calculation formula of “Xn + 1” is performed, the calculation result is set to “Xn ′”, and then the process proceeds to step F10. If it is determined in step F7 that the number is an even number, the flow shifts to step F9 to change "Xn" to "Xn".
After n ′ ″, the process moves to step F10.

In step F10, a calculation formula of " 4 * Xn '" is performed, and the calculation result is obtained as "n".
The value of "n" is set as the number of frames to be used as one unit in the idle state, and the process proceeds to step F11. In step F11, a calculation formula of "No + (3 * No-1)" is performed, and this calculation result is referred to as "Tx". The value of “Tx” is set as the transmission timing Tx of the own station in the idle state, and the process shifts to Step F12.

In step F12, "4 * Xn- (4χ-
1) "and the" χ "set in step F6
Are calculated as “Rx”, and the process proceeds to Step F13. In Step F13, the plurality of “Rx” obtained in Step F12 is used to calculate Step F11.
The value that matches the “Tx” obtained in
The value of "Rx" from which "x" has been removed is set as the reception timing Rx of the own station in the idle state, and this flow chart is ended to shift from the slave unit number setting mode to the next direct talk mode between slave units.

Next, it will be described with reference to a flowchart shown in FIG. 6 for transition operation control to idle slave unit in simultaneous call mode directly between handset.

In the slave number registration mode, when the number of slaves performing direct simultaneous communication between slaves and the respective slave numbers are operated and input, and the transmission / reception timing of each slave in the idle state after synchronization is established is set. This flowchart is started, and the process proceeds to step F21. Step F21
In step F22, all channels of the communication carrier are scanned, and the process proceeds to step F22.
It is determined whether or not a VOX signal has been received from the slave unit having the preset slave unit number by the channel scan by the unit 21. If it is determined that the VOX signal has not been received, the process proceeds to step F23, where the VOX signal is output. If it is determined that it has been received, the process proceeds to step F28.

Then, in step F23, the operation input unit 1
It is determined whether the send button of “0” has been operated, and if it is determined that the send button has not been operated, the process proceeds to step F2.
Then, if it is determined that the transmission button has been operated, the process proceeds to step F24.

In step F24, the carrier sense is performed in the communication carrier to confirm the corresponding slot that can be used for four or more frames in which one slot section is continuous, and the process proceeds to step F25. In step F25, the same is confirmed in step F24. The corresponding slot is used as a reference transmission timing, and at this transmission timing, the VOX of the own station is used.
The signal is transmitted, and the routine goes to Step F26.

In step F26, it is determined whether or not a VOX signal has been received from the slave unit having the preset slave unit number at the reception timing of the own station in the corresponding slot confirmed in step F24, and if the VOX signal has not been received. If it is determined, repeat the above operation proceeds to step F2 4, also when it is determined that the VOX signal is received, the process proceeds to step F 27. In step F27, it is determined that synchronization has been established with the slave unit of the slave unit number included in the VOX signal received in step F26, and this flowchart ends, and the idle state is established after synchronization is established.

On the other hand, if it is determined in step F22 that the VOX signal has been received and the process proceeds to step F28, it is determined in step F28 whether or not the transmission button of the operation input unit 10 has been operated. until it is determined repeats this determination operation, the process proceeds to step F 29 when it is determined that the transmission button has been operated. In step F29, the V received in step F22
The synchronization is performed based on the OX signal, and the process proceeds to step F30. In step F30, the VOX signal of the own station is transmitted at the transmission timing of the own station set in the slave unit number registration mode in the corresponding frame synchronized in step F29. The process moves to step F27.

In step F27, it is determined that synchronization has been established with the slave unit of the slave unit number included in the received VOX signal in the same manner as described above, and this flowchart ends, and the idle state is established after synchronization is established. Steps F25 to F27 perform the same operation as the operation control in the idle state.

The operation control for shifting the slave unit to the talk state and the operation control for shifting from the talk state to the idle state when the slave unit is brought into the idle state after the establishment of the synchronization by the above operation control will be described with reference to the flowchart shown in FIG. Will be explained.

When the idle state after the establishment of the synchronization is established by the operation control or the transition from the talk state to the idle state, this flowchart is started and the routine proceeds to step F31. In step F31, it is determined whether or not a voice message has been input to the microphone 1. If it is determined that no voice message has been input, the process proceeds to step F32. If it is determined that a voice message has been input, the process proceeds to step F39. Transition.

In step F32, the transmission / reception switch 8
In the idle state after the synchronization is established, so as to switch to the transmitting unit at the transmitting timing of the own station and to the receiving unit at the receiving timing of the own station, and perform the transmitting and receiving operation of the VOX signal, and then go to step F33. Transition.
In step F33, it is determined whether the received signal is a VOX signal or audio data when switching to the receiving system in step F32, and if it is determined that the signal is a VOX signal, the process proceeds to step F31. If the above operation is repeated and it is determined that the data is audio data,
Move to step F34. Steps F31 to F33 are operation control in an idle state after synchronization is established.

In step F34, the slave unit number "Nx" of the slave unit to which the audio data is transmitted is determined based on the transmission / reception timing in the idle state after the establishment of the synchronization set in the slave unit number registration mode, and the process proceeds to step F35. . In step F35, it is determined whether or not the transmission timing in the call state of the child device of the child device number "Nx" determined in step F34 matches the transmission timing in the idle state of the own station, and when it is determined that the transmission timings match. Then, the process shifts to step F36. If it is determined that the transmission timings do not match, the process shifts to step F37.

In step F36, the transmission / reception switch 8
So switched to receiver system in the transmission timing in the idle state after establishment control to synchronize, and transmission unit system at the transmission timing in the idle state after synchronization is established by controlling the Step F 3 7 In transceiver changeover switch 8 In step F36.
Then, the process shifts from step F37 to step F38.

In step F38, it is determined whether the received signal is audio data or a VOX signal when the signal is switched to the receiving system, and if it is determined that the signal is audio data, it is determined that the signal is a VOX signal. This determination operation is repeated until the determination is made, and if it is determined that the communication is a VOX signal, it is determined that the communication state has been released, the flow chart is terminated, and the state is shifted to the idle state after synchronization is established. In this determination operation, when voice data is not received for a predetermined number of times or for a predetermined time or more, it may be determined that the call state has been released.

On the other hand, if it is determined in step F31 that a voice message has been input and the process proceeds to step F39, the voice message input to the microphone 1 is subjected to predetermined signal processing and transmitted as voice data in step F39. Move to step F40. In step F40, it is determined whether or not a voice message has been input following the microphone 1, and if it is determined that a voice message has been input, the process proceeds to step F39 to repeat the above operation, and that a voice message has been input. If it is determined that it has not been performed, the process proceeds to step F41.

In step F41, the VOX signal of the own station is transmitted at the transmission timing of the own station in the talking state,
The call state is released, this flowchart ends, and the state is shifted to the idle state after synchronization is established.

Therefore, a simultaneous call is directly performed between the slave units in each of the slave units to which the call is set, and the slave unit for transmitting the call simply inputs a voice message to the microphone 1 without having to perform a button operation for each call transmission. This allows the voice message to be transmitted to another child device, and the other child device can receive and emit the voice message, and the transmission timing does not match in each child device. Communication will not be disabled.

Next, a case will be described in which a call setting condition of a handset performing direct simultaneous call between handset units is identified by a common base unit ID (identification code). Each child device is grouped by its parent device ID,
The master unit ID (hereinafter, referred to as CS-ID) is mutually determined by the control unit 12 by transmitting and receiving signals between the slave units. Therefore, the control unit 12 compares the CS-ID with the CS-ID registered in the own station, and performs control such that a wireless connection is performed when it is determined that the CS-IDs match. The child device used for direct simultaneous communication between child devices can be limited by the common identification code.

Next, a description will be given of a case where a common personal identification number is used as a call setting condition of a slave unit performing direct simultaneous communication between slave units. In the slave unit number registration mode, a common secret number is input to each slave unit by an operation input from the operation input unit 10, and this secret number is used as a secret key code. Thereafter, a transmission signal is based on the secret key code. By performing scrambling processing and transmitting, the receiving side generates a phase amount and a reset timing of a shift register for canceling the scrambling process from a common secret key code and cancels the scrambling process of the received signal, thereby enabling simultaneous transmission between the slave units. Since it is impossible to decode even if it can be received because the transmitted signal is scrambled except for the slaves that have a common password in the call, it is possible to limit the slaves used for direct simultaneous calls between slaves. it can.

Next, a case will be described in which the number of slave units performing direct simultaneous communication between slave units and the number of slave units to be talked after operation of each slave unit number are limited. If you want to make a call connection with only any handset before establishing synchronization, that is, before operating the send button, after setting the number of handset units that perform direct simultaneous call between handset units and the handset number of your own station, The operation input unit 1 is used to enter the slave unit number of the slave unit to be connected to the call before operating the button.
Operation input is performed by operating the numeric key of 0. Then control unit 1
2 displays the slave unit number input based on the operation input by the operation input unit 10 on the display unit 11 and displays the slave unit number displayed on the display unit 11 by operating the transmission button of the operation input unit 10 as a VOX signal. And send it. When each of the slave units receives the VOX signal including the slave unit number, the control unit 12 compares the received VOX signal with the slave unit number of the own station. If the control unit 12 determines that the slave unit number included in the received VOX signal and the slave unit number of the own station do not match, the control unit 12 determines that the own station cannot participate in the call. Judgment is made so that the received VOX signal is not synchronized.

At this time, in the slave unit whose slave unit number included in the received VOX signal matches the slave unit number of the own station, the own station VOX signal transmitted at the own station's transmission timing for synchronization is obtained. , By including the other handset number included in the received VOX signal, synchronization is established only between the handset requesting the call and the handset requesting the call, and the idle state is established. Will be migrated to. And
In this idle state, the VOX signal transmitted at the transmission timing of the own station always includes the other party's slave unit number, thereby automatically maintaining synchronization with the slave unit that has received the call request.

Accordingly, when the slave unit number included in the received VOX signal and the slave unit number of the own station match, the communication connection is established by shifting to the idle state after synchronization is established. Is input, the VOX is released, and a call state is established, so that a call can be made with an arbitrary slave unit.

Then, in a state in which a call is being made with an arbitrary slave unit, the control unit 12 causes the display unit 11 to display the other party's slave unit number included in the VOX signal received first, so that any of the slave units is displayed. When it is possible to determine whether a call request has been received from the mobile device together with the voice message emitted from the speaker 2, and after the communication with the remote device has been completed, the user wants to make a call again with the mobile device that performed the call request operation At
By operating and inputting the slave unit number displayed on the display unit 11 by the same operation as described above, it is possible to synchronize and communicate with only the slave unit that has received the call request. An operation input of an arbitrary slave unit number can be performed without memorizing the unit number.

The data displayed on the display unit 11 is deleted only by operating the operation input unit 10, or the slave unit number previously displayed on the display unit 11 is stored. If the stored slave unit number is called up by operating the operation input unit 10 and is displayed on the display unit 11, the slave unit number displayed on the display unit 11 when the transmission button of the operation input unit 10 is operated. Is included in the VOX signal, so that the slave unit that has made the call request or the slave unit that has made the call request can make a call again in synchronization between the slave units that have performed the call request operation last time.

In the idle state after the synchronization is established,
When it is desired to make a call only with an arbitrary slave unit, the user inputs the slave unit number of the slave unit with which the call connection is desired by operating the ten keys of the operation input unit 10 before inputting the voice message. Then, the control unit 12 displays the slave unit number input by the operation input unit 10 on the display unit 11 and the display unit 11
Is included in the VOX signal and transmitted at its own transmission timing. When each of the slave units receives the VOX signal including the slave unit number, the control unit 1
2 is compared with the slave unit number of the own station, and when it is determined that they match based on the comparison result, predetermined data processing is performed on the audio data received thereafter so that the sound is emitted from the speaker 2. VOX controlled and received by the control unit 12
When it is determined that the slave unit number included in the signal does not match the slave unit number of the own station, control is performed so that predetermined signal processing is not performed on audio data received thereafter.

At this time, the slave unit included in the received VOX signal matches the slave unit number of the own station with the slave unit number of the own station, and the slave unit in the call state enters the other party's slave number included in the received VOX signal. By displaying on the display unit 11 and including it in the VOX signal transmitted at the transmission timing of the own station,
By inputting a voice message to the microphone 1 of the handset that has made the call request after the end of the call of the other handset, only the handset that has made the call request can emit sound data from the speaker 2. And a call state can be maintained between the slave units limited to the slave units.

When a voice message is input to a handset that has not been requested to make a call when a call is being made between handset units limited to the handset unit, the transmission timing may be the same. From the VOX in each slave unit
When a signal other than the signal is received, control is performed so that voice data is not transmitted even at the transmission timing of the own station in the idle state after synchronization is established.

In the embodiment limited to the slave unit after the synchronization is established, a predetermined signal processing is performed on the audio data received by the slave unit in which the slave unit number included in the VOX signal does not match the slave unit number of the own station. The call can not be made by controlling so as not to apply, but it is not limited to this.For example, the secret key code is sent together with the slave unit number and the secret key code is sent only to the own station and any slave unit. By giving the scramble processing, it is also possible to make it possible to communicate only with an arbitrary slave unit. Further, the number of arbitrary slave units that want to make a call may be plural.

Therefore, the VO to be transmitted before the synchronization is established
The X signal includes the slave unit number of the slave unit with which a call is desired to be made, thereby making a call connection with an arbitrary slave unit, and a slave unit of a slave unit with which a call is to be made with a VOX signal transmitted in an idle state after synchronization is established. By including the number, a call can be made with any child device.

As the input of the call setting conditions as described above, for example, in the slave unit number input mode, after inputting the number of slave units performing direct simultaneous communication between slave units and the slave unit number of the own station, "CS- Do you want to group by ID? "
May be displayed on the display unit 11 and a display such as "Do you want to group by personal identification number?" May be made by the operation input from the operation input unit 10, and the present invention is not limited to this. For example, instead of the display by the display unit 11, the notification may be made by voice from the speaker 2 as a receiver.

Further, in this embodiment, the number of slave units for performing simultaneous direct communication between the slave units is four. However, the present invention is not limited to this. For example, when the number of slave units is five or six, Select and enter the slave unit number so that it does not overlap with the slave unit, and
The transmission timing in the idle state may be set in each slave unit by using the unit as the first to 24th units, and the number of slave units may be set to seven or eight. Select and enter the machine numbers so that they do not overlap, and use the four frames as one unit to
The transmission timing in the idle state may be set in each slave unit by being recognized as the 32nd,
Further, the number of slave units may be increased.

Furthermore, in this embodiment, since data for one slot (625 μsec) is recovered in one frame (5 msec) in the ADPCM 5, two persons cannot talk at the same time. For example, two or more ADPCMs are provided. If they are combined in an analog fashion after the reconciliation, two people can talk at the same time.

[0087]

As described above, according to the first aspect of the present invention, the number of slave units performing direct simultaneous communication between slave units in each slave unit and a different slave unit number for each slave unit are set in advance. Thus, the transmission / reception timing of the own station in the idle state is set. Then, at the time of starting the direct simultaneous call between the slaves, a detection signal including the slave number of the own station is transmitted to the other slaves, and based on the detection signal and the transmission / reception timing of the own station in the idle state. When synchronization is established by synchronizing transmission and reception in a call state, and when the above-mentioned detection signal is received also in another slave unit, transmission / reception of the own station in the idle state of each slave unit with the received detection signal is performed. Synchronization is established by synchronizing transmission and reception in a call state based on the timing of the above, and if the signal received by the other slave unit is an audio signal, the transmission operation does not shift to the transmission operation at the transmission timing of the audio signal. By switching to the receiving operation at the same time, it is possible to perform a direct simultaneous call between the slave units by automatically entering the talking state by inputting a voice message to the microphone. Therefore, it is possible to save the trouble of the switch operation for inputting the voice message by the user, and also to prevent the mutual transmission of the voice signal in the voice communication state, thereby preventing the interference of the radio waves and performing the voice communication well. Can be.

According to the second aspect of the present invention, after the synchronization of transmission and reception in the call state is established, the control means controls the transmission timing of the own station in the idle state and the transmission timing of the slave unit to which the audio signal has been transmitted in the call state. When it is determined that the transmission is different, the detection signal transmission means is controlled to transmit the detection signal including the slave unit number of the own station to the other slave unit at the transmission timing of the own station in the idle state, thereby enabling the idle state in the call state. Since the transmission and reception timing of the state can be ensured, the detection signal can be transmitted and received according to the previously set transmission and reception timing of the idle state at the time of transition from the talk state to the idle state, and re-searching for an empty channel is omitted. be able to.

According to the third aspect of the present invention, each slave unit is identified by a common identification code, and synchronization is established between only the slave units having the same identification code to shift to a call state. Thus, since it is possible to limit only the slaves identified by the common identification code as the slaves performing direct simultaneous communication between the slaves, it is possible to perform a direct talk between the slaves with a high degree of secrecy.

According to the fourth aspect of the present invention, at the time of activation of the direct simultaneous call between the slave units, if the other handset to which the direct simultaneous call between the slave units is desired is selected, the call designation slave unit number is assigned to each slave unit. Is established, and only when it is determined that the call designation slave unit number included in the received detection signal matches the slave unit number of the own station, transmission / reception synchronization is established in the call state. Can be arbitrarily limited after setting the slave unit number, so that all slave units that are set to perform direct simultaneous talk between slave units can be limited. Rather than making a call, you can make a call by limiting a specific slave unit from the set slave units, and you can make a direct simultaneous call between slave units with a higher degree of secrecy. Asked the slave user No it is possible to perform a private conversation.

According to the fifth aspect of the present invention, when the direct simultaneous call between the slave units is activated, each of the slave units receives a detection signal including the call designation slave unit number. When it is determined that the specified slave unit number included in the terminal and the slave unit number of the own station match, the slave unit number included in the received detection signal is displayed, so that the designated unit Since it is possible to easily determine whether or not the call has been received, the designated call request was easily issued by the user's operation input when re-calling the slave unit to which the designated call request was issued after the communication was completed. A transition can be made to a call state with the slave unit.

According to the sixth aspect of the present invention, when a direct simultaneous call between slave units is started, each slave unit receives a detection signal including a call designation slave unit number, and the received detection signal When it is determined that the specified slave unit number included in the mobile station and the slave unit number of the own station match, the detection signal transmitted from the own station as the specified slave unit number included in the received detection signal as the specified slave unit number , It is possible to continue the call with the slave unit to which the designated call request has been issued even after the transition to the idle state, so that the call designation is performed in the slave unit that has received the designated call request. By simply inputting a voice message to the microphone, it is possible to perform a call again with the slave unit for which the designated call request has been issued.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a slave unit in a digital cordless telephone according to one embodiment of the present invention.

FIG. 2 is a timing chart showing transmission / reception timings in an idle state of each slave unit in the digital cordless telephone.

FIG. 3 is a timing chart showing transmission / reception timing in a call state of each slave unit in the digital cordless telephone.

FIG. 4 is a timing chart showing transmission / reception timing in a call state of each slave unit in the digital cordless telephone.

FIG. 5 is a flowchart showing operation control of direct simultaneous call between slave units in the digital cordless telephone.

FIG. 6 is a flowchart showing operation control of direct simultaneous call between slave units in the digital cordless telephone.

FIG. 7 is a flowchart showing operation control of direct simultaneous call between slave units in the digital cordless telephone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microphone 2 Speaker 3 PCM codec part 4 VOX determination circuit 5 ADPCM codec part 6 Channel codec part 7 RF part 8 Transmission / reception switch 9 Antenna 10 Operation input part 11 Display part 12 Control part

Claims (6)

(57) [Claims] 1. A digital system comprising a master unit and a plurality of slave units, capable of making a call by making transmission and reception different in time, and enabling direct simultaneous talk between the plurality of slave units. In a cordless telephone, a slave unit number setting means for setting, for each slave unit, the number of slave units performing direct simultaneous communication between the slave units and assigning a different slave unit number to each slave unit, and the slave unit number setting means Transmission / reception setting means for setting the transmission / reception timing of the own station in the idle state based on the number of child devices and the child device number set by the user, and voice input detection means for detecting the presence / absence of sound input to the microphone And including a slave unit number of the own station in a detection signal from the voice input detection unit, and transmitting a detection signal including the slave unit number of the own station to another slave unit based on the timing set by the transmission / reception timing setting unit. A detection signal sending means for sending, upon receiving the detection signal, the detection signal thereof received,
Synchronization establishment means for synchronizing transmission / reception in a call state based on the slave unit number included in the detection signal and transmission / reception timing set by the transmission / reception timing setting means; A transmitting means for transmitting to a transmission operation at a transmission timing, and transmitting a sound input to the microphone at this time to another slave unit; and a receiving means for shifting to a receiving operation at a reception timing of the own station after the synchronization is established by the synchronization establishing means. Means for determining a source slave based on the reception timing of the audio signal and the transmission / reception timing set by the transmission / reception timing setting means when the audio signal is received by the reception means, and transmission of the own station in the transmission timing and an idle state in the call state of the machine tie When the ring and is matched, the transmission timing
And a control means for controlling the transmitting means and the receiving means so as to shift to a receiving operation. 2. When the transmission timing of the own station in the idle state is different from the transmission timing of the voice signal transmission source in the talking state, the control means controls the slave of the own station in the transmission timing of the own station in the idle state. 2. The digital cordless telephone according to claim 1, wherein a detection signal including the unit number is transmitted to another slave unit. 3. The communication device according to claim 1, wherein each of the slave units is identified by a common identification code, and the synchronization of the communication state is established by the synchronization establishing means only between the slave units having the same identification code. The digital cordless telephone according to claim 1. 4. An operation input means for inputting a handset number of a handset desired to perform a direct simultaneous call between handset units, and a handset number input by the operation input means is used as a detection signal from the voice signal detection means. A call designation assigning means to be included; and a call designation slave unit number comparing means for comparing the call designation slave unit number included in the received detection signal with the slave unit number of the own station when the detection signal is received. Only when it is determined that the specified telephone number matches based on the result of the comparison by the specified telephone number comparing means, the control means transmits the detection signal having the specified telephone number and the transmission / reception timing. 2. The digital code receiver according to claim 1, wherein said synchronization establishing means is controlled to synchronize transmission and reception in a call state based on the transmission and reception timing set by said setting means. Phone. 5. A slave unit number included in a detection signal in which said call-designated slave unit number matches when it is determined based on the comparison result by said call-designated slave unit number comparison means that said call-designated slave unit number matches. 5. A digital cordless telephone according to claim 4, further comprising a display means for displaying a message. 6. The call designation assigning means, when it is determined that the call designation slave unit numbers match based on the comparison result by the call designation slave unit number comparison means, detects that the call designation slave unit numbers match. 5. The digital cordless telephone according to claim 4, wherein a handset number included in the signal is included as a call designation handset number in the detection signal from the voice signal detecting means.