JP3318501B2 - Digital cordless telephone system - 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 communication system capable of improving the transfer rate by using a plurality of wireless channels when wirelessly connecting the wiring in data communication such as personal computer communication using deemed voice. It relates to a cordless telephone system.

[0002]

2. Description of the Related Art Conventionally, personal computer communication using deemed voice using a modem has been generally performed, and data communication using deemed voice such as home-use karaoke and Internet TV has become more and more active. ,
There is also a rapidly growing demand for making these wired wires wireless and performing data communications, etc. anywhere.
Although a method based on wireless wiring using HS or the like has been used, the speed of data communication using deemed voice using PHS has generally been limited to about 9600 bps.
Here, a conventional data communication using a deemed voice by the PHS will be described with reference to the drawings. FIG. 6 is a block diagram of a conventional PHS slave unit. The configuration of FIG.
Is a microphone, 602 is a microphone amplifier, 603 is a PCM codec for converting analog signals and PCM data, 60
4 is ADPCM for converting 8-bit PCM data and compressed 4-bit data, 605 is a codec path, 606 is a QPSK modulation / demodulation circuit, 607 is a transmission / reception circuit, 608 is a speaker, 609 is a speaker amplifier, and 610 is a data communication I for assumed voice. An interface for deemed audio such as a / F section, and 611 is an antenna.

FIG. 7 is a block diagram of a conventional PHS master unit. To explain the configuration of FIG. 7, 701 is a modular jack, 702 is a line I / F (interface) unit,
703 is a PCM that converts an analog signal and PCM data
Codec 704 is 8-bit PCM data and compressed 4
ADPCM for converting bit data, 705 is a codec path, 706 is a QPSK modulation / demodulation circuit, 707 is a transmission / reception circuit, and 708 is an antenna.

FIG. 8 is an example showing a data relationship between a master unit and a slave unit in the case of the TDMA / TDD system. The flow of data from the base unit to the slave unit is defined as down, and the flow of data from the slave unit to the master unit is defined as ascend. From T1 to T4, the timing of transmission by the master unit, and from R5 to R8, The reception timing by the master unit, R1 to R4 indicate the reception timing by the slave unit, and T5 to T8 indicate the transmission timing by the slave unit. Further, a is data created by the PCM codec 703 of the master unit and compressed by the ADPCM 704 and transmitted as one slot data from the master unit to the slave unit, and a ′ is created by the PCM codec 603 of the slave unit. The data compressed by the ADPCM 604 is collected as data for one slot and transmitted from the slave unit to the master unit.

FIG. 9 shows a process of compression and decompression by the ADPCM 905. PCM codec 90 when sending
1 to 8-bit PCM data (90
2 to 904), the ADPCM 905 compresses the data into 4-bit data (906 to 908), and transmits it to the codec path 909. At the time of reception, 4-bit data (906 to 908) is transmitted from the codec path 909 to the ADPCM 90.
5, the ADPCM 905 restores 8-bit PCM data (902 to 904) from the 4-bit data and transmits it to the PCM codec 901.

Hereinafter, the conventional operation will be described with reference to FIGS. 6 and 7. FIG. First, a case will be described in which communication data is transmitted from the master unit to the slave unit by using a deemed voice. The deemed audio data is usually input to the modular jack 701 of FIG. 7 via an analog public line. After that, the line I / F
After passing through the section 702 and being converted to 8-bit PCM data by the PCM codec 703, the ADPCM 704 converts the data into 8-bit PCM data.
Compressed to bits and passed through codec path 705
The signal is transmitted as a radio wave from an antenna 708 by a transmission / reception circuit 707 via a PSK modulation / demodulation circuit 706. On the slave side, the radio wave is received by the antenna 611 of FIG. 6 and input to the QPSK modulation / demodulation circuit 606 via the transmission / reception circuit 607, and from there, the ADPCM 60 via the codec path 605.
4 and converted into 4-bit to 8-bit PCM data, converted into an analog signal by the PCM codec 603, transmitted to a data communication terminal interface such as the data communication I / F unit 610 for deemed voice, and then transmitted to a modem or the like. Sent out. In this way, the deemed voice data received by the master unit from the line is transmitted to a modem or the like connected to the slave unit.

Next, a case will be described in which communication data is transmitted from the slave unit to the master unit by the deemed voice. The deemed voice data is input via the modem to the data communication I / F unit 610 for the deemed voice of the slave unit in FIG. After that, PC
After being converted into 8-bit PCM data by the M codec 603, the data is compressed to 4 bits by the ADPCM 604, passes through the codec path 605, and passes through the QPSK modulation / demodulation circuit 60.
The signal is transmitted as a radio wave from the antenna 611 by the transmission / reception circuit 607 through 6. On the master unit side, the radio wave is received by the antenna 708 shown in FIG. 7 and is input from the transmission / reception circuit 707 to the ADPCM 704 via the QPSK modulation / demodulation circuit 706 via the codec path 705, where it is restored to PCM data of 4 bits to 8 bits and converted to PCM data. Codec 70
The signal is converted into an analog signal at 3 and sent to the modular jack 701 via the line I / F section 702. In this manner, the assumed voice data received from the modem or the like connected to the slave unit is transmitted to the line on the master unit side.

[0008]

In the conventional system, the PC
The amount (the number of bits) of the PCM data created by the M codec 603 and the PCM codec 703 is the radio 1
Since it is larger than the amount of data (the number of bits) that can be transmitted in the channel, the ADPCM 604 and the ADPCM 70
According to No. 4, it was necessary to go through the compression / decompression process of PCM data. However, in the current ADPCM, the reproducibility of voice data when the data is passed through the compression / decompression process of PCM data is reduced. Therefore, in data communication and the like, this is one of the serious causes for lowering the communication speed. there were.

[0009]

SUMMARY OF THE INVENTION The present invention divides PCM data into a plurality of radio signals without performing a compression / decompression process of PCM data, which degrades the reproducibility of voice data at the time of deemed voice data communication. It is provided with a means for transmitting to a channel and combining it on the receiving side to restore the PCM data before division.

According to the present invention, it is possible to eliminate the influence on the reproducibility of the voice signal (including the deemed voice) by the ADPCM when performing the data communication using the deemed voice using the wireless communication according to the above-described configuration. The communication speed can be greatly improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the base unit uses two slots of TDMA / TDD for the radio channel,
In addition, the slave unit realizes two wireless channels by using two slave units, and divides 8-bit PCM data into upper 4 bits and lower 4 bits and transmits / receives the data via the previous two wireless channels. Is performing data communication.

FIGS. 5 (a) and 5 (b) show two main examples of data communication when the present invention is implemented ((a) distribution / combination circuit mounted type and (b) distribution / combination circuit external type). This is shown conceptually. Although the distribution / synthesizing circuit type shown in FIG. 1A uses an example of a slave unit dedicated to data communication, an ordinary slave unit may be used and a distribution / synthesizing circuit may be mounted on the slave unit.
5, reference numerals 501 and 512 denote analog public lines.
513 is a modular jack arranged on a wall or the like, 50
Reference numeral 3,514 denotes a parent device of the PHS embodying the present invention;
Reference numerals 515 and 516 denote PHS slave units having input / output terminals for PCM data and codec path data; 505, a slave unit dedicated to data communication without a speaker or microphone having a built-in distribution / synthesis circuit; 506, 518 modems; Is a personal computer, 508, 509, 520, 521 are wireless channels, 517 is an external distributing / combining device, 511, 522
523 is a communication cable for PCM data / codec path data, and 510 and 524 conceptually represent walls. These are the PHSs that implemented the present invention.
2 conceptually show two examples of data communication using.

FIG. 1 is a block diagram showing a connection state between a slave unit 505 of a PHS equipped with a distribution / synthesis circuit embodying the present invention and a slave unit 504 with a PCM data / codec path data input / output terminal. First, the configuration of the slave unit 505 with the distribution / synthesis circuit shown in FIG. 1 will be described. Reference numeral 101 denotes a data communication I / F unit for deemed voice, and 102 denotes an 8-bit PCM at the time of transmission.
A distribution / synthesis circuit that divides data into upper 4 bits and lower 4 bits, and combines and restores 8-bit PCM data before division from the upper 4 bits and lower 4 bits during reception. P to convert
CM codec, 104 ADPCM for converting 8-bit PCM data and compressed 4-bit data, 105 a codec path, 106 a QPSK modulation / demodulation circuit, 107 a transmission / reception circuit, 108 an antenna, 119 PCM data / codec path data input / output terminal It is. Next, PC
Handset 5 with M data / codec path data input / output terminal
To explain the configuration of 04, 109 is a microphone, 110
Is a microphone amplifier, 111 is a PCM codec, 112
Is ADPCM, 113 is a codec path, 114 is Q
PSK modulation / demodulation circuit, 115 is a transmission / reception circuit, 116 is an antenna, 117 is a speaker, 118 is a speaker amplifier, 1
Reference numeral 20 denotes a PCM data / codec path data input / output terminal. Reference numeral 511 denotes a communication cable for PCM data / codec path data, which conceptually shows data transfer between the PCM data / codec path data input / output terminals 119 and 120.

FIG. 2 is a block diagram of a PHS master unit embodying the present invention. 2, a modular jack 201, a line I / F 202, a PCM codec 203 for converting analog signals and PCM data, an ADPCM 204 for converting 8-bit PCM data and compressed 4-bit data, 205 is a codec pass,
206 is a QPSK modulation / demodulation circuit, 207 is a transmission / reception circuit,
08 is an antenna, 209 is a codec path used for the second communication, and 210 is a distribution / combination circuit.

FIG. 3 shows an example of a data relationship between the master unit and the slave unit in the case of the TDMA / TDD system. The flow of data from the base unit to the slave unit is defined as down, and the flow of data from the slave unit to the master unit is defined as ascend. From T1 to T4, the timing of transmission by the master unit, and from R5 to R8, The reception timing by the master unit, R1 to R4 indicate the reception timing by the slave unit, and T5 to T8 indicate the transmission timing by the slave unit. Also, a1 and a2 are data created by the PCM codec 203 of the master unit and divided into 4 bits by the distribution / combination circuit 210, and transmitted as one slot data from the master unit to the slave unit. 1, a'2 is the PCM codec 10 of the slave unit
3, data divided into 4 bits by the distribution / synthesis circuit 102 are collected into one slot and transmitted from the slave unit to the master unit.

FIG. 4 shows distribution / combination by the distribution / synthesis circuit 405.
The synthesis process is shown. At the time of transmission, 8-bit PCM data (402 to 404) is input from the PCM codec 401 to the distribution / combination circuit 405,
5 is divided into 4-bit data (406 to 411) and transmitted to the codec path 412 and the codec path 413, respectively. At the time of reception, 4-bit data (406 to 41) is output from the codec path 412 and the codec path 413.
1) is input to the distribution / synthesis circuit 405, and the distribution / synthesis circuit 405 converts the 4-bit data (406 to 411) to 8
Bit PCM data (402-404) is restored and P
It is transmitted to the CM codec 401.

Hereinafter, the operation at the time of data communication according to the present invention will be described with reference to FIGS. First, a case will be described in which communication data is transmitted from the master unit to the slave unit by using a deemed voice. The deemed audio data is usually input to the modular jack 201 of FIG. 2 via an analog public line. Thereafter, the signal passes through a line I / F unit 202, is converted into 8-bit PCM data by a PCM codec 203, is divided into upper 4 bits and lower 4 bits by a distribution / synthesis circuit 210, and is divided into a codec path 205 and a codec path 205. 209 respectively. After that, the antenna 20 is transmitted by the transmission / reception circuit 207 through the QPSK modulation / demodulation circuit 206.
8 and transmitted as radio waves. In the slave unit, the radio waves are received by the antenna 108 in FIG.
The signal is input to a K modulation / demodulation circuit 106, from which it is input to a distribution / combination circuit 102 via a codec path 105. Similarly, in the handset 504 with PCM data / codec path data input / output terminal, the signal is received by the antenna 116 of FIG. 1 and input from the transmission / reception circuit 115 to the QPSK modulation / demodulation circuit 114, and from there, via the codec path 113, The PCM data of the cordless path data input / output terminal 120 which is output to the codec path data input / output terminal 120 and the distribution / synthesizing circuit-incorporated slave unit 505
9 and is input to the distribution / synthesis circuit 102. Therefore, each 4-bit data is restored to 8-bit PCM data, converted to an analog signal by the PCM codec 103, transmitted to a data communication terminal interface such as the data communication I / F unit 101 for deemed voice, and transmitted to a modem or the like (FIG. a) modem 506). In this way, the deemed voice data received by the master unit from the line is transmitted to a modem or the like connected to the slave unit.

Next, a case will be described in which communication data is transmitted from the slave unit to the master unit by means of a deemed voice. The deemed voice data is input via the modem to the data communication I / F unit 101 for the deemed voice of the slave unit in FIG. After that, PC
After being converted into 8-bit PCM data by the M codec 103, it is divided into upper 4 bits and lower 4 bits by the distribution / combination circuit 102,
CM data / codec path data input / output terminal 119
Output to The data output to the codec path 105 passes through the QPSK modulation / demodulation circuit 106 and the transmission / reception circuit 1
At 07, it is transmitted as a radio wave from the antenna 108.
The 4-bit divided PCM data output to the PCM data / codec path data input / output terminal 119 is transmitted from the PCM data / codec path data input / output terminal 120 of the slave unit having the PCM data / codec path data input / output terminal. It is input, passes through a codec path 113, passes through a QPSK modulation / demodulation circuit 114, and is transmitted as a radio wave from an antenna 116 by a transmission / reception circuit 115.

The master unit transmits the radio wave to the antenna 20 shown in FIG.
8 and transmitted from the transmission / reception circuit 207 through the QPSK modulation / demodulation circuit 206 to the distribution / combination circuit 210 via the codec path 205 and the codec path 209, where the data is restored from each 4-bit data to 8-bit PCM data. The signal is converted into an analog signal by the PCM codec 203 and transmitted to the modular jack 201 via the line I / F unit 202. In this manner, the assumed voice data received from the modem or the like connected to the slave unit is transmitted to the line on the master unit side.

Also, during normal communication not using a plurality of wireless channels, the handset 505 equipped with a distribution / synthesis circuit does not pass through the distribution / synthesis circuit 102 and has the same
The communication via the M104 and the slave unit with the PCM data / codec path data input / output terminal
Signals are input to the PCM codec 111 via the DPCM 112, input from the speaker amplifier 118 to the speaker 117, and input signals from the microphone 109 are input to the PCM codec 111 via the microphone amplifier 110 to perform communication. AD without passing through distribution / synthesis circuit 210 even in master unit
Communication is possible by using one channel wirelessly by compressing the PCM data via the PCM 204.

The switching to the data communication mode based on the voice regarded as a call is automatically performed by detecting a carrier transmitted by the modem of the data communication partner, or a carrier transmitted by the modem on the own side and a signal indicating off-hook. Do. Also, if either the master unit or the slave unit detects a signal for performing data communication, after wireless establishment, using data in the control information area of the channel being used,
Prior to wireless establishment, the communication partner is automatically switched to the data communication mode by notifying the communication partner of the call information at the time of wireless establishment or the incoming call information. Further, the transmitting side transmits the data for detecting synchronization deviation at a predetermined timing, and the receiving side detects whether the data received at the same timing is data that can be predicted from predetermined synchronization deviation detection data, It is detected whether or not the consistency of the composite data has shifted due to the influence of the communication status or the like.

Next, an example of a data synthesizing method on the receiving side will be described with reference to FIGS. First, as shown in FIG. 10, on the transmitting side, f, f, f... Are added to the upper 4 bits so that the receiving side can first determine the upper 4 bits and the lower 4 bits.
-Continue transmitting 0, 0, 0, ... in the lower 4 bits.
On the receiving side, the channel receiving f, f, f... Is assigned to the upper 4 bits, and the channel receiving 0, 0, 0.
Determine the bits. Next, as shown in FIG. 11, the transmission side transmits special bit deviation correction data such as 1, 2, and 3 so that the reception side can correct the deviation of the reception timing between the upper 4 bits and the lower 4 bits. When the receiving side receives bit shift correction data such as 1, 2, and 3 on one of the channels, it then obtains bit shift correction data on the other channel. Then, one of the received data
, 1, 2 and 2, 3 and 3 are corrected so that the positional relationship of the received data is combined. Thereafter, the combination is performed while maintaining the positional relationship. FIG. 12 shows an example of a calling procedure when the above-described combination method is specifically executed. Here, the distinction between the call and the data communication is distinguished by whether the call button of the slave unit is pressed or the off-hook signal to the data communication I / F unit. If an off-hook signal to the data communication I / F unit is detected as shown in the sequence of FIG. 12, the slave unit calls the master unit with a special number such as *** indicating data communication. When the master unit recognizes the call using the special number, the master unit starts the data communication mode sequence thereafter.

FIG. 13 shows an example of a detection method when the synchronization of the combination is shifted for some reason during the synthesis of 4-bit data to 8-bit data. The transmitting side inserts and transmits predetermined data 0xff at a predetermined timing, and the receiving side determines whether or not the synchronization has been lost based on whether or not the data received at the predetermined timing is 0xff. Deciding. If the received data is other than 0xff, the synchronization is re-established.

[0024]

As described above, according to the present embodiment, even during data communication using deemed voice, the PCM data is divided and transmitted over a plurality of wireless channels, thereby improving the reproducibility of voice data. The communication speed of data communication using deemed voice can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a PHS slave according to an embodiment of the present invention.

FIG. 2 is a block diagram of a PHS master according to an embodiment of the present invention;

FIG. 3 is a diagram relating to TDMA / TDD slots and transmission data in one embodiment of the present invention.

FIG. 4 is a diagram related to distribution and synthesis of a distribution / synthesis circuit in one embodiment of the present invention.

FIG. 5 is a diagram showing the concept of data communication in one embodiment of the present invention.

FIG. 6 is a block diagram of a conventional PHS slave unit.

FIG. 7 is a block diagram of a conventional PHS base unit.

FIG. 8 is a diagram related to conventional TDMA / TDD slots and transmission data.

FIG. 9 is a diagram showing a conventional ADPCM and a compression function.

FIG. 10 is a diagram related to a method of determining upper 4 bits and lower 4 bits in one embodiment of the present invention.

FIG. 11 is a diagram of a bit shift correction method for upper 4 bits and lower 4 bits according to an embodiment of the present invention.

FIG. 12 is a diagram showing an example of a calling procedure on two channels in one embodiment of the present invention.

FIG. 13 is a diagram illustrating an example of a synchronization shift detection method according to an embodiment of the present invention.

[Explanation of symbols]

101, 610: Data communication I / F for deemed voice
, 102, 210, 405 ... distribution / combination circuit
103, 111, 203, 401, 603, 703,
901, PCM codec, 104, 112,
204, 604, 704, 905... ADPCM,
105, 113, 205, 209, 412, 413, 6
05, 705, 909 ... Cordic pass, 10
6, 114, 206, 606, 706... QPSK modulation / demodulation circuit, 107, 115, 207, 607, 707
... Transceiver circuits 108, 116, 208, 61
1, 708: antenna, 109, 601: microphone, 110, 602: microphone amplifier, 11
7, 608: speaker, 118, 609: speaker amplifier, 119, 120: PCM data / codec path input / output terminal, 201, 502, 51
3, 701: modular jack, 202, 70
2 ... line I / F unit, 402, 403, 404, 9
02, 903, 904... PCM data, 406,
407, 408, 409, 410, 411 ... divided PCM data, 501, 512 ... analog public line, 503, 514 ... PHS base unit, 504,
515, 516: Handset with PCM data / codec path data input / output terminal, 505: Handset dedicated to data communication with distribution / synthesis circuit 506, 518: Modem, 507, 519: Personal computer, 508 , 50
9, 520, 521 ... wireless channel, 510, 5
24 ... wall, 511, 522, 523 ... PCM data / codec path data cable, 517 ...
・ External type distributing / synthesizing device, 906, 907, 908
..Compressed PCM data

Claims (5)

(57) [Claims] An apparatus comprises a master unit for transmitting and receiving voice and data, and a plurality of slave units, wherein the master unit communicates data with the plurality of slave units using a plurality of wireless channels, and the slave unit has at least one wireless unit.
A digital cordless telephone system that communicates data to a base unit using one wireless channel, divides the data, allocates the divided data to a plurality of wireless channels, and performs time-division communication with the base unit. In a digital cordless telephone system for improving data communication speed between slave units, data is divided into a plurality of wireless channels for transmission to a master unit and at least one slave unit, and data is divided from received divided data before division. A digital signal distribution / synthesis unit that synthesizes the divided data to reproduce the data of each unit is connected, and multiple slave units are connected to each other to restore the divided data received from the master unit for voice communication. The digital signal distribution / combination unit reproduces and outputs the data before division, and outputs the data before the division. The data is distributed to each slave unit and transmitted to the master unit without performing compression for voice communication. By transmitting and receiving predetermined bit shift correction data to the wireless channel at the start of communication, the bit shift is performed. A digital cordless telephone system, which corrects a positional relationship between received data transmitted in a time-division manner over a plurality of wireless channels based on correction data. 2. Transmission and reception of predetermined synchronization establishment data to the wireless channel at the start of communication, thereby allocating received data to a plurality of wireless channels based on the synchronization establishment data, and then based on the bit shift correction data. 2. The digital cordless telephone system according to claim 1, wherein the positional relationship between the received data that has been time-divisionally communicated through a plurality of wireless channels is corrected. 3. A master unit for transmitting and receiving voice and data, and a plurality of slave units, wherein the master unit communicates data to a plurality of slave units using a plurality of wireless channels, and at least one slave unit communicates with the plurality of slave units.
A digital cordless telephone system that communicates data to a base unit using one wireless channel, divides the data, allocates the divided data to a plurality of wireless channels, and performs time-division communication with the base unit. In a digital cordless telephone system for improving data communication speed between slave units, data is divided into a plurality of wireless channels for transmission to a master unit and at least one slave unit, and data is divided from received divided data before division. A digital signal distribution / synthesis unit that synthesizes the divided data to reproduce the data of each unit is connected, and multiple slave units are connected to each other to restore the divided data received from the master unit for voice communication. The digital signal distribution / combination unit reproduces and outputs the data before division, and outputs the data before the division. The data is distributed to each child device and transmitted to the parent device without performing compression for voice communication. The mode determination of the voice communication mode and the data communication mode is performed by a carrier signal transmitted by data communication or off-hook. A digital cordless telephone system, which is automatically performed by detecting a signal instructing the user. 4. A base unit for transmitting and receiving voice and data, and a plurality of slave units, wherein the master unit communicates data with the plurality of slave units using a plurality of wireless channels, and the slave unit has at least one
A digital cordless telephone system that communicates data to a base unit using one wireless channel, divides the data, allocates the divided data to a plurality of wireless channels, and performs time-division communication with the base unit. In a digital cordless telephone system for improving data communication speed between slave units, data is divided into a plurality of wireless channels for transmission to a master unit and at least one slave unit, and data is divided from received divided data before division. A digital signal distribution / synthesis unit that synthesizes the divided data to reproduce the data of each unit is connected, and multiple slave units are connected to each other to restore the divided data received from the master unit for voice communication. The digital signal distribution / combination unit reproduces and outputs the data before division, and outputs the data before the division. The data is distributed to each slave unit and transmitted to the master unit without performing compression for voice communication, and at least one of the master unit and the slave unit is established before wireless communication between the master unit and the slave unit is established. When a signal for performing data communication is detected, a notification is made to the communication partner based on call information or call information at the time of wireless establishment, and the communication partner is automatically shifted to the data communication mode, and the communication with the master unit is performed. If at least one of the master unit and the slave unit detects a signal for performing data communication after wireless establishment of the slave unit, a notification is made to the communication partner using data in the control information area of the used channel. A digital cordless telephone system characterized by automatically shifting a communication partner to a data communication mode. 5. A master unit for transmitting and receiving voice and data, and a plurality of slave units, wherein the master unit communicates data to a plurality of slave units using a plurality of wireless channels, and at least one slave unit communicates with the plurality of slave units.
A digital cordless telephone system that communicates data to a base unit using one wireless channel, divides the data, allocates the divided data to a plurality of wireless channels, and performs time-division communication with the base unit. In a digital cordless telephone system for improving data communication speed between slave units, data is divided into a plurality of wireless channels for transmission to a master unit and at least one slave unit, and data is divided from received divided data before division. A digital signal distribution / synthesis unit that synthesizes the divided data to reproduce the data of each unit is connected, and multiple slave units are connected to each other to restore the divided data received from the master unit for voice communication. The digital signal distribution / combination unit reproduces and outputs the data before division, and outputs the data before the division. Data is distributed to each slave unit and transmitted to the master unit without performing compression for voice communication. The transmitting side transmits data for detecting synchronization deviation at a predetermined timing, and the receiving side transmits the data for detecting synchronization deviation. A digital cordless telephone system for detecting a synchronization deviation of the divided data of each wireless channel and correcting a positional relationship of the received divided data.