JPH10276477A - Cordless telephone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable communication or the like with a visitor even when a hand set moves out of a radio range by originating a call to a telephone number preserved in a memory when it is detected the hand set is out of the range. SOLUTION: When a doorphone button is pressed by the visitor and a doorphone response signal is provided, the location of the hand set (PS) is judged, namely, it is judged whether the hand set is inside or outside the radio range of the base unit. When it is judged the hand set is outside the range of the base unit, based on the telephone number of the hand set previously stored in the memory, the base unit originates a call through a public line network to the hand set in an outdoor mode. When the connection with the hand set is not completed, message information from the visitor is stored in the RAM of memory. The base unit originates a call through the public line network to the hand set at every prescribed time in the outdoor mode. When the connection with the hand set is completed, the message information, which is stored in a memory 6 at the base unit, with the visitor is sent through the public line network to the hand set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless telephone system having a parent device and a child device, and more particularly to a cordless telephone system having a door phone function in the parent device.

[0002]

2. Description of the Related Art In recent years, a portable cellular phone (PHS) has rapidly spread as a second-generation cordless telephone replacing a home cordless telephone. This PHS is
A base station (CS: Cell Statio) connected to a public telephone network in an area where public telephone users are concentrated, such as in station premises or downtown areas
n), the terminal (PS: PersonalSt)
The market is expanding as a system in which a person carrying an ation) can use the telephone anytime and anywhere as a personal telephone as well as a public telephone. This PHS is equivalent to a terminal PS corresponding to a slave unit provided that a self-service CS (hereinafter referred to as a base unit (BS)) is provided as a home base unit instead of a base station.
When brought into the home (hereinafter referred to as a handset (PS)), it can be used as a home cordless telephone.

[0003] Also, even when the portable unit is carried away from home and moves out of the wireless communication area of the base unit, the control station of the PHS monitors the presence of the portable unit based on location registration information from the base station. Therefore, it can be used as a general mobile phone. That is, in addition to the outdoor mode in which communication is performed via a base station installed outdoors, the PHS slave has an indoor mode in which communication is performed through a master unit installed indoors and connected to a public line network. Two modes are provided so as to be switchable. Also, some base units are provided with an absence recording function, so that the contents of a call received during absence are automatically recorded, and the recorded contents can be heard after returning home.

[0004]

By the way, there are products equipped with a door phone function in a base unit of a home cordless telephone and a telephone with an ordinary answering machine, and the like. The parent machine does not have a door phone function. For this reason, a growing number of people who purchase a second generation cordless telephone in place of the home cordless telephone require a door phone function for the home base unit. Also, as described above, since the PHS and the conventional home cordless telephone have different mechanisms and usage, even if the PHS is simply provided with the same intercom function as the conventional home cordless telephone, the following problems occur. There is.

[0005] That is, if there is a visitor in a door phone connected to the master unit in which the PHS slave unit is registered, if the owner of the slave unit is within the wireless communication area of the master unit, the slave unit / master unit will be used.・ Calls can be made between doorphones, but if the owner of the slave unit is out of the wireless communication area of the master unit, the master unit cannot notify the slave unit that there is a visitor. The owner does not know that he is visiting. The present invention has been made in view of the above-mentioned problems, and a home parent device is provided with a door phone function, and a person carrying a child device has moved far away from the wireless communication area of the parent device. Even in such a case, it is an object of the present invention to provide a cordless telephone system which can communicate with a visitor or listen to a visitor's message stored in an answering machine function.

[0006]

According to the first aspect of the present invention, there is provided a wireless communication with a base unit connected to a public line network,
In a cordless telephone system using a handset that can be used to switch wireless calls to and from a base station connected to a public line network, the base unit has a detection unit that detects the location of the handset, and a door phone has been pressed. A detection unit, a control unit, and a memory for storing a telephone number. The control unit detects that the intercom has been pressed, and the detection unit detects that the slave unit is in the call area. When it is detected that the telephone number is out of the range, a telephone number stored in a memory in advance is called.

According to a second aspect of the present invention, in the cordless telephone system according to the first aspect, the master unit stores a message input through a microphone of the door phone in a memory, and the detection unit detects that the slave unit has a call area. Is detected, the telephone number registered in the memory in advance is called, and the message stored in the memory is transmitted.

According to a third aspect of the present invention, in the cordless telephone system according to the first or second aspect, when the interface in the wireless section complies with the second generation cordless telephone system standard, the message transmission is performed by a predetermined function. It is characterized in that it is performed using an optional area of a channel.

According to a fourth aspect of the present invention, in the cordless telephone system according to the first or second aspect, when the interface in the wireless section conforms to the second generation cordless telephone system standard, transmission of a message is performed by using various channels. This is characterized by using a channel in which a channel identification code representing the type is set as an option.

[0010]

In a cordless telephone system using a handset capable of switching between a radio call with a base unit connected to a public line network and a radio call with a base station connected to the public line network, The master unit has a detection unit that detects the location of the slave unit, a detection unit that detects that the door phone has been pressed, a control unit,
Having a memory for storing a telephone number, the control unit detects that the door phone has been pressed, and, when the detection unit detects that the handset is outside the range of the call area,
The main unit detects that the door phone has been pressed by the visitor, even if the person carrying the sub unit is outside the wireless communication area of the main unit, because it is configured to call the telephone number stored in the memory in advance. Transmits information to the child device via the public line network,
Even if you are away from the door phone, you can talk to visitors.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In describing a method of transmitting a voice message with a door phone function of a cordless telephone system used in an embodiment of the present invention, it conforms to a second generation cordless telephone system standard (RCR STD-28). Fig. 1 (a) shows the form of the communication system between the base station and the slave unit.
This will be described briefly using FIG. First, the slave unit can communicate with the master unit provided in the home wirelessly, and since the master unit is connected to the public line network, the slave unit can be connected to the public line network through the master unit to make a call. It is possible to make a call with another slave unit by connecting to a wireless line via a base station connected to a public line network.

[0012] Therefore, the PHS handset executes a call by controlling the connection of a plurality of types of line networks, and the line network is controlled by using the radio control channel of each system. . That is, the slave unit receives a control channel from the base station during standby, that is, a logical control channel (hereinafter, LCCH).
) To monitor the incoming call to the own device, and if there is an incoming call from the base station, establish a communication channel via the LCCH and start a call. When there is an incoming call to the handset, the base station transmits the incoming call via the LCCH,
The slave detecting the incoming call via the CH is an information channel (hereinafter referred to as TCH) which is a communication channel with the base station via the LCCH.
) And talk over that channel.
Also, for outgoing calls, a TCH is established via this LCCH, and a call is started.

According to the RCR STD-28, the PHS access method is a four-channel multiplex multi-carrier TDMA-TDD (Time Division Duplex).
: Full-duplex communication in which transmission and reception are switched at the same frequency). FIG. 1B is a schematic diagram showing a configuration of a TDMA-TDD frame. Four slots T1, T2, T3, T4 (downlink slots) transmitted from the base station to each slave unit, and four slots R1, R2, R3, R4 (uplink slots) transmitted from each slave unit to the base station. Are alternately arranged. That is, the base station uses the four slots T1 to T4 to simultaneously make a call to each slave unit, and when each slave unit detects an incoming call from the base station, the base station determines whether the base station has four T1 to T4 slots. A call is made to the base station using four slots R1 to R4 corresponding to the slots.

This one frame is 5 ms, and each slot is transmitted as a 625 μs burst signal. The code length of each slot is 240 bits, and the modulation signal speed is 240 bits × 625 μs = 384 kbps.
It has become. The above-mentioned slot is used by each user in common, and a control physical slot (control channel) in which a function channel required for control such as setting of a communication physical slot is set, and each user is exclusively used for communication. However, there is a communication physical slot (communication channel) in which a control channel and an information channel necessary for individual call setting control are set.

FIGS. 2 and 3 show coding formats of various channels belonging to a control channel and a communication channel, respectively, and there are six types of formats. FIG. 2A shows a downlink broadcast channel (hereinafter referred to as BCCH).
) Or paging channel (hereinafter referred to as PCH). The first R (4 bits) indicates a transient response ramp time that guarantees a burst rise time, and the SS (2 bits) indicates a start symbol. , PR
(62 bits) is a preamble for reproducing a clock signal from a received signal to establish bit synchronization, UW (32 bits).
(Bit) is a unique word composed of a frame synchronization word, and CI (4 bits) is a channel identification code (called a CI code) representing the type of each of the various channels shown in FIGS. The next source identification code (42 bits) is the identification code of the base station on the transmitting side, the next I (62 bits) is information on BCCH or PCH, and the CRC (16 bits) is an error check bit.

FIG. 2 (b) shows an uplink dedicated cell channel (hereinafter referred to as SCCH). This format is provided with a destination identification code (28 bits) which is not included in the above (a). This is the identification code of the other party (base station),
The identification code of the mobile station is set as the source identification code. (C)
The downlink SCCH is a channel for transmitting signal control information sent from the base station to the slave unit, and the positions of the destination identification code and the source identification code are opposite to those in the case of the downlink SCCH in (b) above. I have. (D) is an uplink user packet channel (hereinafter referred to as USCCH), and (e) and (f) are downlink USCCHs.

FIG. 3A shows an uplink synchronization burst,
R, SS, PR, having the same configuration as in FIGS. 2B and 2D.
UW, CI, destination identification code, calling identification code are set,
Upward idle bits are provided in the subsequent 34 bits,
Finally, a CRC (16 bits) is set. Also,
The downlink synchronization burst of FIG. 3B has the same configuration as the uplink synchronization burst, and FIGS. 3C and 3D show a user packet channel (hereinafter, referred to as USPCH) and a high-speed associated control channel of FIG. FACCH) is a channel that can be used during communication, and is capable of controlling call setting and transmitting wireless information as well as user information. CI in this format
Low-speed associated control channel (hereinafter referred to as SACCH)
Is used to transmit the control signal during communication by combining with the SACCH of the succeeding frame in 5 ms, and is used to transmit the control signal interrupted during communication as FACCH information at the I (160 bits) portion at high speed. Can be

FIG. 3 (f) shows an information channel (hereinafter referred to as TCH) for transmitting traffic information or a VOX function for transmitting voice (or low-speed data) (transmission output is turned ON / OFF depending on the presence or absence of voice). OFF: hereinafter referred to as a VOX) channel. In the I (information) portion of this format, 160-bit voice or traffic information is set in hardware at the time of transmission. Where TCH is
A point-to-point bi-directional channel that transfers user information and user information control signals. As described above, the USCCH of (d), (e) and (f) shown in FIG. 2 and the USPCH of (c) and (d) shown in FIG. 3 are both point-multipoint bidirectional channels. , An optional channel provided for transmitting control information, user packet data, and the like, which can be used freely by the user.

Next, a cordless telephone system according to an embodiment of the present invention will be described with reference to FIG. First, FIG. 6A shows a case where a base unit is connected to a public line network, a door phone used in the cordless telephone system of the embodiment of the present invention is connected to the base unit, and a child registered in the base unit. A state diagram when the mobile device is in the wireless communication area of the parent device is shown, and (b) shows a state diagram when the child device moves out of the wireless communication area of the parent device. (C) is a state diagram when the slave unit is in a wireless communication area of a base station connected to a public line network. In the following description, the interface between the master unit and the slave unit, and the interface between the base station and the slave unit are RCR STD-28.
Shall be compliant with

Next, the circuit configuration will be briefly described with reference to the block diagram of the master unit and the slave unit used in the cordless telephone system of the present invention shown in FIG. First, a block diagram of the master unit shown in FIG. Signal transmission / reception unit 2
Performs frequency conversion processing of a transmitted / received signal. At the time of reception, after performing a frequency conversion processing on a 1.9 GHz high frequency signal received by the antenna 1 into an IF (intermediate frequency) signal, a communication processing unit at the next stage Supply 3 At the time of transmission, a modulated wave by π / 4 shift QPSK, which is a modulation method used in a cordless telephone system, is frequency-converted to 1.9 GHz and output to the antenna 1.

The communication processing unit 3 performs modulation / demodulation processing by π / 4 shift QPSK, frame synchronization, and slot format processing. At the time of reception, the reception signal subjected to frequency conversion processing by the signal transmission / reception unit 2 receives the π / 4 signal. A shift QPSK demodulation process is performed, a UW (synchronization signal) is extracted from the received data, frame synchronization is performed, and control data and audio data in the received data are supplied to the control unit 5 and the audio processing unit 4, respectively. At the time of transmission, control data is added to the audio data supplied from the audio processing unit 4 to create transmission data, and a unique word is added to format the data.
Signal transmitting / receiving unit 2 as a π / 4 shift QPSK modulated signal
Send to

The audio processing unit 4 performs compression / expansion processing of the digital data supplied from the communication processing unit 3 and performs D / D processing.
A conversion is performed. At the time of reception, A supplied from the communication processing unit 3
The DPCM audio signal is expanded by decoding it into a PCM audio signal, the PCM audio signal is D / A converted, and the generated analog audio signal is output from the speaker 7. At the time of transmission, the analog audio signal input from the microphone 8 is
/ D conversion, and encodes the PCM audio signal into an ADPCM audio signal to compress the signal and supply it to the communication processing unit 3.

A door phone detecting unit 10 is connected to the control unit 5, and detects that a door phone button is pressed, and sends out an intercom response sound via a speaker 7 connected to the voice processing unit 4. Then, the presence or absence of a visitor is notified, and a call is made to a telephone number stored in the memory 6 in advance. If the answering mode is set by a switch (not shown), a message indicating that the user is absent is sent out via the speaker of the door phone by means of the recorded sound, and the message recorded at this time is recorded in advance in the memory 6. Make a call to the phone number stored in and send it automatically. The control unit 5 has a ROM in which an operation program for pre-initializing the master unit and a predetermined value are stored in advance, and an R which temporarily stores data such as voice messages handled by the control unit 5.
It has a memory 6 made of AM.

FIG. 7B is a block diagram of the slave unit. The difference from the master unit is that the slave unit has a reception level measuring means 9 as a detecting unit. The reception level measuring unit 9 detects a high-frequency signal from the reception unit of the signal transmission / reception unit 2 and detects the high-frequency signal to obtain, for example, a DC voltage corresponding to the strength of the radio wave (reception level). By supplying the obtained DC voltage to the display unit of the slave unit (not shown), the reception level of the received radio wave in the area where the slave unit is used can be known by a numerical value or a pictorial display, and the parent unit described later can be used. It is used as a DC voltage to be compared with a threshold value when determining whether it is inside or outside the wireless communication area of the device. In addition, the slave unit has a function of automatically determining its own location and automatically switching to the outdoor or indoor mode.

Next, the operation of the cordless telephone system according to the present embodiment configured as described above will be described. The control of the operation of the cordless telephone system of the present embodiment is mainly performed by the control unit 5 of the master unit in FIG. 7A, and FIG. 9 shows a flowchart of the control. First, step S1
, The presence or absence of an intercom response signal obtained from the intercom detector 10 when the intercom button provided on the intercom is pressed is monitored. Next, in step S2, the presence or absence of a visitor is monitored. If there is no visitor and no intercom response signal is obtained (step S2: NO), the intercom monitoring of step S1 is continued, and the intercom button is pressed by the visitor, and the intercom is pressed. If a response signal has been obtained (step S2: YES), the process proceeds to step S3, and the slave unit (P
The location of S), that is, whether the child device is inside or outside the wireless communication area of the parent device is determined.

FIG. 8 shows a method for judging the location of the slave unit.
This will be described with reference to (a) and (b). FIG. 8A shows a method of measuring the reception electric field strength of the LCCH periodically transmitted by the master unit using the reception level measurement means 9, and FIG.
Is a method in which the parent device polls the child device and monitors the response. That is, in the method shown in FIG. 8A, when the slave receives the LCCH of the master and the reception level of the LCCH received by the slave is equal to or lower than the threshold, the slave sets the wireless communication area of the master. The parent device determines that the child device has moved out of the communication area by notifying a message to shift to the outside by a method described later. At this time, the slave unit is automatically switched to the outdoor mode. When the slave unit again enters the wireless communication area of the master unit, the slave unit detects that the reception level of the LCCH has exceeded the threshold value, and similarly determines that the slave unit has entered the wireless communication area. By notifying the parent machine,
The parent device can recognize the location of the child device. At this time, the slave unit is automatically switched to the indoor mode.

In the method shown in FIG. 8B, the master sends a message to the slave as to whether or not it is in the wireless communication area by a method described later (polling). If the user is in the communication area, the inquiry can be received. When the inquiry is received, a response message is sent to the parent device (polling response), so that the parent device can recognize that the child device is in the communication area. At this time, if there is no polling response, the base unit performs polling a predetermined number of times, and if there is no polling response within the predetermined number of times, it means that the slave unit is not in the wireless communication area of the base unit. Is determined to have moved out of the call area. When the slave unit enters the wireless communication area of the master unit again, the master unit can perform location registration specified in RCR STD-28, so that the master unit can recognize the location of the slave unit.

Further, since the slave unit can receive the polling from the master unit, if a polling response is transmitted to the master unit, the master unit can recognize that the slave unit has entered the communication area. . Next, in step S4, when the slave is in the wireless communication area of the master (step S4).
4: NO) (the state diagram of FIG. 6A) shifts to step S5, in which the master unit calls the slave unit in the indoor mode, and the RCR STD-28 communicates with the slave unit. A compliant control sequence is performed. When a communication path is established between the parent device and the child device according to this control sequence, the process proceeds to step S6, and the parent device sends out audio from a microphone provided in the door phone as transmission information to the child device.

The slave unit determines that the information is information from a visitor based on a display of a door phone response of a display device provided in the main body, and a call between the slave unit and the door phone is performed by pressing a talk button of the slave unit. Even if the user is away from the door phone in the wireless communication area of the master unit, the conversation with the visitor is performed via the slave unit. If it is determined in step S4 that the location of the child device is outside the wireless communication area of the parent device (step S4: YES) (the state diagram of FIG. 6B), the process proceeds to step S7, and the flow proceeds to step S7. Makes a call to the slave via the public line network in the outdoor mode using the telephone number of the slave which is stored in the memory 6 in advance.

Next, the process proceeds to step S8, where the master unit monitors whether or not the master unit can be connected to the slave unit via the public line network. In step S8, when the connection between the master unit and the slave unit is completed (step S9: YES), in step S6, a call is performed between the slave unit, the master unit, and the intercom by pressing the talk button of the slave unit. Will be If the connection with the child device has not been completed (step S9: NO), the process proceeds to step S9, and the message information from the visitor is stored in the RAM of the memory 6. That is, when the doorphone button is pressed by the visitor, if the power of the slave unit outside the wireless communication area of the master unit is turned off, the connection with the slave unit cannot be established. The absence response message is sent in advance to the provided RAM from the speaker of the door phone, and the message of the visitor is extracted through the microphone of the door phone.
It is stored in the RAM as message information.

Next, the process proceeds to step S10, where the master unit calls the slave unit via the public line network at predetermined time intervals in the outdoor mode. Next, in step S11, the connection with the slave unit is monitored. If the connection with the slave unit is not completed (step S11: NO), a call is issued to the slave unit via the public line network at predetermined time intervals in step S10. Repeat the call. When the connection with the slave unit is completed (step S11: Y
ES) proceeds to step S12, and sends the message information with the visitor stored in the memory 6 of the master unit to the slave unit in step S9 via the public line network by a method described later.

Next, a method of exchanging messages between the slave unit and the master unit in steps S3 and S12 will be described. First, in step S3, when the parent device determines the location of the child device, one of them is as shown in FIG.
As shown in (a), the slave monitors the reception level of the LCCH transmitted by the master, compares the level with a predetermined threshold, and determines whether the slave is in the wireless communication area with the master. There is a method of notifying whether the message is out of the area. When notifying this message, for example, by using the method described below, the control unit 5 can notify by a control sequence conforming to RCR STD-28.

That is, one method is to use an optional area of a functional channel. As a method of using the function channel option area, for example, the above-described FACC
There is a method of putting information to be notified in an H / SACCH message. As shown in FIG. 10, the FACCH / SACCH message format is assigned an 8-bit protocol identifier and a message type. When the upper three bits of the message type are assigned to (011), the option information is included in other information elements. Message area,
That is, an area that can be freely used by the user can be secured. Therefore, if the message type in FIG. 10 is designated as an option, any information can be put in the other information elements in FIG. 10, so that the information to be notified can be put in the other information elements. .

Further, information to be notified to the USCCH / USPCH may be entered, or if the function channel has an optional area, information to be notified may be entered to the area. Further, as another method for the slave unit to notify the master unit whether the wireless communication area is inside or outside the wireless communication area, a channel identification code (C
There is a method of using a channel in which “I code” is set as an option. The CI code is an identification code indicating the channel type of the slot.
When used as a functional channel such as CH or PCH, a unique identification code is written into the CI code, and when used as an option, an optional identification code is written into the CI code.

That is, if an optional identification code is written in the CI code, the user can freely use the slot. Therefore, in the present embodiment, the CI code of the slot transmitted from the slave to the master is optional. Is set, and a message indicating whether the area is inside or outside the wireless communication area of the master unit is placed on the slot, so that the master unit can recognize the area where the slave unit is located. Also, in the case of FIG. 8B, that is, when the master unit polls the slave unit and monitors the polling response to the slave unit, similarly, the option area of the above-mentioned function channel or the CI code is set as an option. The polling operation between the parent device and the child device can be performed using the set channel.

However, when the master unit polls the slave unit, there is a method using the BCCH in addition to the above-described example as a method using the option area of the function channel. The BCCH is a one-way channel from the parent device to the child device, and when the user freely transmits a message from the parent device to the child device, the BCCH can also be used. This method will be described below. RCR STD-28 defines a notification message defined in a link channel establishment phase for establishing a handshake in a radio section using the BCCH. FIG. 4 shows the content of the private information message, and the optional information message is defined as a message that can be used arbitrarily for each system in the private message. Note that the self-mark in the figure indicates that the message is a matter to be standardized for a self-service system.

FIG. 5 shows a message format, which illustrates an example of a message format when an option information notification message is used. The shaded portions are areas that can be used freely for each system. Therefore, if the message type of the broadcast message transmitted from the master unit to the slave unit by using the BCCH is set in the option information notification message, and the information regarding the polling is put in an area which can be freely used for each system, the master unit can be set as the slave unit. It is possible to poll machines. The master unit can poll the slave unit not only for the option information notification message but also for other notification messages as long as the option area can be secured.

In step S12, when the message information of the visitor stored in the memory of the master unit is sent to the slave unit, the option area of the function channel or the CI code is set to the option similarly. It is possible to send message information of the visitor using the channel. However, if the message information of the visitor is a voice message, the information channel I (TCH)
It goes without saying that it may be placed on the part shown in FIG.

In the cordless telephone system according to the embodiment of the present invention, an example has been described in which a visitor is present during absence and a message of a visitor is stored in the RAM. When a monitoring device is provided, the obtained image information is stored as digital data on the RAM, and the data is stored in the option area of the above-described function channel or the channel in which the CI code is set as an option. May be transmitted to the slave unit so that the display based on the information can be viewed on the slave unit equipped with the display device. Further, in the present embodiment, a configuration in which the master unit controls the connection between the door phone and the slave unit based on the location of the slave unit has been described. However, the present invention is not limited to this. It may be configured to control the home electric appliance by recognizing.

[0040]

According to the cordless telephone system of the embodiment of the present invention, when the door phone is operated by the visitor, even if the slave unit is out of the wireless communication area of the master unit, the public line network is established. Since the base station receives a call to the slave through the base station, the message information of the visitor can be heard through the base station. In addition, since the message information of the visitor is stored in the memory of the master unit and automatically transmitted to the master unit, when the slave unit cannot be connected to the master unit, the message of the visitor is displayed. You can listen to information.

[Brief description of the drawings]

FIG. 1 is a 4-channel multiplex multi-carrier TDMA-TD.
FIG. 3 is a schematic diagram showing an LCCH frame configuration in a D (Time Division Duplex: full-duplex communication in which transmission and reception are switched at the same frequency).

FIG. 2 shows coding formats of various channels belonging to a control carrier.

FIG. 3 shows coding formats of various channels belonging to a communication carrier.

FIG. 4 is a diagram showing a private information message.

FIG. 5 is a diagram showing a message format of a notification message.

FIG. 6 is a conceptual diagram showing one embodiment of a cordless telephone system of the present invention.

FIG. 7 is a block diagram of a master unit and a slave unit used in the cordless telephone system of the present invention.

FIG. 8 is a diagram showing a communication sequence between a master unit and a slave unit used in the cordless telephone system of the present invention.

FIG. 9 is an operation flowchart of the intercom and the slave unit used in the cordless telephone system of the present invention.

FIG. 10: FACCH based on RCR STD-28
It is a figure which shows the message format of / SACCH.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Antenna 2 ... Signal transmission / reception part 3 ... Communication processing part 4 ... Audio processing part 5 ... Control part 6 ... Memory 7 ... Speaker 8 ... Microphone 9 ... .Reception level measuring means 10... Doorphone detector

Claims (4)

[Claims] 1. A cordless telephone using a handset capable of switching between a radio call with a base unit connected to a public line network and a radio call with a base station connected to the public line network. In the system, the master unit includes a detection unit that detects the location of the slave unit, a detection unit that detects that a door phone has been pressed, a control unit, and a memory that stores a telephone number. When the detection unit detects that the door phone has been pressed, and when the detection unit detects that the slave unit is outside the range of the call area, the telephone number stored in the memory in advance is used. A cordless telephone system characterized by making a call. 2. The master unit stores a message input via a microphone of the door phone in the memory, and when the detection unit detects that the slave unit is out of a communication area, 2. The cordless telephone system according to claim 1, wherein a call is made to a telephone number registered in advance in a memory, and a message stored in said memory is transmitted. 3. In the cordless telephone system,
3. The cordless telephone system according to claim 1, wherein when the interface of the wireless section complies with the second generation cordless telephone system standard, the transmission of the message is performed using an option area of a predetermined function channel. . 4. In the cordless telephone system,
When the interface of the wireless section complies with the second generation cordless telephone system standard, the transmission of the message is performed using a channel in which a channel identification code representing the type of each channel is set as an option. Item 3. The cordless telephone system according to item 1 or 2.