JP3473270B2 - Telephone equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone device for informing a called party of a call when a call is made by a third party during a call.

[0002]

2. Description of the Related Art A telephone station which, when called from another subscriber during a call, informs the calling subscriber that there is a call, and enables switching of the calling party according to the instruction of the calling subscriber. Service (hereinafter referred to as "call waiting").

FIG. 10 is an explanatory diagram for explaining call waiting. As shown in FIG. 10, when the subscriber A and the subscriber B are in a call and the subscriber C (third party) makes a call to call the subscriber A, the central office switch 40 calls the subscriber A from another party. Send an audible signal to let you know. The subscriber A knows from the audible signal that there is a call from another person, and when the subscriber A desires to make a call with the subscriber C, it sends a signal requesting the switching of the other party to the central office switch 40. With this signal, the central office switch 40 opens a communication path between the subscriber A and the subscriber C and makes the subscriber B stand by.

[0004]

However, in the conventional telephone apparatus on the subscriber side, when a call is made from a third party, the called party is only notified by a signal tone. In this way, only by notifying the called party with a signal sound, it is not possible to recognize who is the calling party during the call unless the line is switched, which takes time and effort, and does not switch the line. If, during a call, the called party selects whether the caller in the current call (previous caller) or the caller coming in later (previous caller) needs to speak first. There was a problem that there was no means for doing so.

By the way, in the call waiting service, when there is an incoming call from a third party during a call,
It is conceivable that the central office will send information such as the telephone number and name of this third party. Such call waiting allows the caller to know who the third party is before switching the call to the third party.

However, when the information of the third party is transmitted from the central office to the telephone device, if the line from the central office to the telephone device is an analog line, it will be transmitted using the voice band. It is conceivable that the data from the central office will be destroyed by this voice signal.

The present invention solves the above-mentioned conventional problems. In call waiting, the information of the calling party (third party) transmitted by the central office can be stably received, and the called party can visually make a call. It is an object of the present invention to provide a telephone device that can recognize a person's name and telephone number.

[0008]

In order to achieve the above object, the present invention provides an alert signal detection for detecting an alert signal input from a central exchange when there is a call from a third party during a call. Means, calling party information detecting means for detecting calling party information coming from the telephone line, and mute in the sending circuit when receiving the calling party information issued by the central office after the alert signal is sent. By providing the mute control means for turning on, it becomes possible to detect the caller information that arrives at the time of call waiting so as not to be destroyed by a voice signal, etc., and display the detected caller information on the display device. This allows the called party to visually recognize the name and telephone number of the later calling party during the call.

[0009]

[0010]

[0011]

[0012]

[0013] According to a first aspect of the present invention includes a base unit connected to a telephone line, a telephone apparatus comprising a wireless communication capable handset between the master unit, the master unit, A sending circuit for sending a voice signal to the telephone line, a receiving circuit for receiving a voice signal from the telephone line, and for detecting an alert signal input from the central exchange when there is a call from a third party during a call. Alert signal detection means, caller information detection means for detecting caller information coming from the telephone line, and a calling circuit when receiving caller information issued by the central office after the alert signal is sent. Mute control means for muting the caller, master device control means for storing the caller information detected by the caller information detection device in a storage device, and mute command data for causing the slave device to mute the reception. sent to the machine, then, between Only and a calling party information transmitting means for transmitting the calling party information stored to the child device, the child device, multiplying the reception mute immediately detects the data transmitted from the base unit, following the It is provided with a caller information receiving means for receiving the caller information signal from the base unit and ending reception of the caller information before canceling the reception mute. When the caller information is transmitted to the handset, the handset mutes the reception, so that the handset does not hear the data sound as noise.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing a telephone device according to a first embodiment of the present invention. In FIG. 1, 1
Is a telephone line, 2 is an alert signal detecting means for detecting an alert signal inputted through the telephone line 1, and 3 is an ACK signal (confirmation signal) indicating that the alert signal has been detected is sent to the telephone line 1. ACK signal sending means 4 is a calling party information detecting means for detecting calling party information coming from the telephone line 1.

Reference numeral 5 is a mute control means for muting (silence) the transmitting circuit 10 described later. Reference numeral 6 denotes a storage device for storing the caller information detected by the caller information detecting means 4 and response information indicating whether or not the caller has responded, and 7 denotes the caller stored in the storage device 6. It is a display device which distinguishes and displays information and response information. Reference numeral 8 is a control means composed of a microcomputer. Reference numeral 9 is an interface with the telephone line 1, 10 is a transmitting circuit for transmitting a voice signal, 1
Reference numeral 1 is a receiving circuit for inputting a voice signal, and 12 is a handset having functions of a microphone and a speaker. Reference numeral 13 is a hook switch for opening and closing the telephone line 1.

The operation of the telephone device configured as described above will be described with reference to the flowchart of FIG. At the time of call waiting, the central office switch outputs an alert signal indicating that there is a call from a third party,
An alert signal is input to the telephone device via the telephone line 1. This alert signal consists of dual tones of 2130 Hz and 2750 Hz, and the signal has a time width of 80 ± 5 ms. When the alert signal detection means 2 detects a 2130 Hz signal and a 2750 Hz signal at the same time, the detection output is output to the control means 8, and the control means 8 outputs the detection output from the alert signal detection means 2 for 80 ± 5 ms. It is determined that the alert signal is an alert signal, and ACK signal sending means 3
(S1).

Upon receiving the notification, the ACK signal sending means 3 automatically sends an ACK signal indicating that the alert signal has been detected to the telephone line 1 (S2). ACK signal is 1
60 ± composed of frequencies of 633 Hz and 941 Hz
It is a signal of 5 ms and is sent to the central office switch via the telephone line 1.

Then, in accordance with an instruction from the control means 8, the mute control means 5 mutes the transmission circuit 10 after a predetermined time has passed from the transmission of the ACK signal to the telephone line 1 (S).
3). That is, the signal from the mute control means 5 activates the mute circuit 10a in the transmitter circuit 10 to lower the gain of the transmitter amplifier or to make the amplifier inoperative.

The central office switch, in accordance with the ACK signal, information of the calling party (third party) who made the call (calling party information: calling party name,
A telephone number, etc.) to the telephone device of the present invention.

Next, the control means 8 determines whether or not the caller information detection means 4 has detected the caller information coming from the telephone line 1 (S4).

FIG. 3 is a data diagram showing an example of caller information. When it is determined in step 4 that the calling party information is not detected, the calling party information detecting means 4 is in a standby state until the calling party information is detected. When it is determined in step 4 that the calling party information is detected, the control means 8 stores the calling party information in the storage device 6 (S5).

Next, the control means 8 determines whether or not the caller information detection means 4 has finished detecting the caller information (S6). If it is determined in step 6 that the detection of the calling party information has not ended, the storage of the calling party information in the storage device 6 is continued (S5, S6). When it is determined in step 6 that the detection is completed, the control means 8 causes the mute control means 5 to cancel the mute set in the transmitter circuit 10 (S7). Next, the caller information shown in FIG. 3 is displayed on the display device 7 (S8).

As described above, the timing at which the mute control means 5 mutes is matched with the timing at which the telephone exchange (station exchange) transmits the caller information in response to the ACK signal. As a result, the voice signal from the telephone device is stopped when the central office sends the caller information, so that the caller information is destroyed by the voice signal when receiving the caller information. Never.

Next, the control means 8 determines whether or not the called party responds to the calling party (S9). Hook switch 13 opens the phone line 1 for a certain period of time,
If the called party answers the call from the calling party, the control means 8
Stores the response information indicating that the caller has answered in the storage device 6 (S10).

FIG. 4 is an explanatory diagram showing a case where the history of incoming calls stored in the storage device 6, that is, the caller information and the response information received so far are displayed on the display device 7. In FIG. 4, 14 is response information indicating whether or not the call of the calling party has been answered, 15 is the name of the calling party, and 16 is the telephone number of the calling party. In the example shown in FIG. 4, it is indicated that the called party has answered (marked with ◯) to the calling party “ABC” having the telephone number “12345”.

In the first embodiment, the control means 8 is composed of a microcomputer, but the means 2 to 5 may be composed of a microcomputer. In addition, as the caller information sent from the central office,
It may be the case that only the telephone number is used, or the name of the calling party is also added, and it depends on the service of the telephone company that subscribes. If the telephone device is equipped with an electronic telephone directory in which the name of the person or company that has the telephone number in pair with the telephone number is recorded as character data, the caller information sent from the central exchange during the call It is also possible to retrieve and display the name corresponding to the telephone number sent by accessing the electronic telephone directory, even if only the number is used.

As described above, according to the present embodiment, at the time of call waiting, the calling party information received by the calling party information detecting means 4 is prevented from being destroyed by the voice signal sent to the telephone line 1. The caller information can be surely acquired, and the caller information and the response information indicating whether or not the call from the caller is answered are stored in the recording device 6 and displayed on the display device 7. By doing so, it is possible to visually recognize the caller information and the response information, and thus it is possible to easily recognize the caller who is not answering,
It is possible to easily determine which caller to call again.

(Second Embodiment) A second embodiment of the present invention will be described below. FIG. 6 is a block diagram showing a telephone device according to a second embodiment of the present invention, showing a telephone device composed of a master unit and a slave unit. In FIG. 6, 21
Is a telephone line, and 22 is a master unit connected to the telephone line 21.

In the base unit 22, 23 is an alert signal detecting means for detecting an alert signal input via the telephone line 21, and 24 is a telephone line 21 for notifying that the alert signal is detected by an ACK signal. It is an ACK signal transmitting means for transmitting an ACK signal (confirmation signal). Further, 25 is a calling party information detecting means for detecting calling party information coming from the telephone line 21, 26 is a mute control means for muting a transmitting circuit 31 described later, and 27 is a calling party information detecting means 25. A storage device for storing the generated caller information, 28 is a caller information transmitting means for transmitting the caller information stored in the storage device 27 as a caller information signal to a slave unit 33 which will be described later, and 29 is a micro This is a master unit control means configured by a computer. Reference numeral 30 is an interface with the telephone line 21, 31 is a transmitter circuit for transmitting a voice signal, 32 is a receiver circuit for inputting a voice signal, and ANT1 is a master antenna for radiating a caller information signal as a radio wave signal.

Reference numeral 33 is a slave unit capable of wireless communication with the master unit 22. In the handset 33, ANT2 is a handset antenna for receiving an incoming caller information radio signal, and 34 is an AN.
Caller information receiving means for detecting the caller information from the caller information signal received at T2, and 35 is the caller information receiving means 3
A display device for displaying the calling party information detected in 4 and a reference numeral 36 is a slave unit control means constituted by a microcomputer. 37 is a microphone, 38 is a speaker, 39 is a transmitting amplifier, and 40 is a receiving amplifier.

The operation of the telephone device configured as described above will be briefly described. At the time of call waiting, the caller information detecting means 25 of the base unit 22 detects the caller information and the detected call is made. The calling party information is stored in the storage device 27, and the calling party information is displayed on the display device 35 of the child device 33.

Next, the operation of the apparatus of FIG. 6 will be described in detail with reference to the flowchart of FIG. First, when an alert signal (a signal of 2130 Hz and a signal of 2750 Hz) indicating that a third party has called is input to the master device 22 via the telephone line 21 during call waiting, the alert signal detection means 23 outputs the signal. It detects and outputs the detection output to the master unit control means 29. Base unit control means 2
9 indicates that the detection output from the alert signal detecting means 23 is 80 ±
If it continues for 5 ms, it is judged as an alert signal, and AC
The K signal transmission means 24 is notified (S11). Upon receiving the notification, the ACK signal transmitting means 24 automatically transmits to the telephone line 21 an ACK signal informing that the alert signal has been detected (S12).

Next, the mute control means 26 mutes the transmission circuit 31 according to an instruction from the master control means 29, and activates the mute circuit 31a in the transmission circuit 31 to lower the gain of the transmission amplifier. (S13).

Next, the master unit control means 29 controls the telephone line 21.
It is determined whether or not the caller information detecting means 25 has detected the caller information coming from (S14). When it is determined in step 14 that the calling party information is not detected, the calling party information detecting means 25 is in a standby state until the calling party information is detected. When it is determined in step 14 that the calling party information is detected, the master unit control means 29 stores the calling party information in the storage device 2.
No. 7 is stored (S15).

Next, the master unit control means 29 determines whether or not the caller information detection means 25 has finished detecting the caller information (S16). If it is determined in step 16 that the detection of the calling party information has not ended, the storage of the calling party information in the storage device 27 is continued (S15, S16). When it is determined in step 16 that the detection of the caller information has ended, the master unit control means 29 causes the mute control means 26 to cancel the mute set in the transmitter circuit 31 (S1).
7). Similar to the previous embodiment, by matching the timing of muting with the timing at which the exchange of the central office transmits the calling party information, when the calling party information is received, the calling party information is destroyed by a voice signal or the like. Never.

Next, the master unit control means 29 controls the storage device 27.
The calling party information stored in the calling party information sending means 28 is sent to the handset 33 via the antenna ANT1 (S
18).

The calling party information receiving means 34 of the child device 33 receives, through ANT2, the calling party information signal transmitted from the calling party information sending means 28 through ANT1, and receives the calling party information. If the caller information is detected (S19), the child device control means 36 causes the display device 35 to display the caller information detected in step 19 (S20).

In the second embodiment, it is described that the handset device control means 36 displays the caller information on the display device 35. However, the handset device control means 36 further functions as a handset device 33. When a response is made, the response information is sent to the master unit control means 29
You may make it memorize | store in the memory | storage device 27 via.

Further, in the second embodiment, the master unit control means 29 and the slave unit control means 36 are composed of microcomputers, but the means 23 to 26 may be composed of microcomputers.

As described above, according to the present embodiment, the caller information that arrives at the time of call waiting is detected, the detected caller information is stored in the storage device 27, and the caller information is stored in the child device. Display device 3 of the child device 33 that is sent to the device 33
Since it is displayed in 5, the called party can visually recognize the calling party information in the child machine distant from the parent machine and talk to the calling party corresponding to the calling party information. Whether or not it can be easily determined. Further, by transmitting response information indicating whether or not a response has been made from the handset device control means 36 to the handset device control means 29, the caller information and the response information can be displayed separately on the display device 35. , It is possible to easily recognize the caller who has not responded, and to easily determine which caller to call again.

(Third Embodiment) The third embodiment of the present invention will be described below. FIG. 7 is a block diagram showing a telephone device according to the third embodiment, and the configuration of the master device 22 is the same as the configuration shown in FIG. In the cordless handset 41, A
NT2, caller information receiving means 34, and display device 35 are shown in FIG.
It is similar to the configuration shown in. 37 is a microphone, 38 is a speaker, 42 is a transmitting amplifier, 43 is a receiving amplifier, and 43a is a mute circuit provided in the receiving amplifier 43. FIG. 8 is a timing chart in the embodiment of the present invention in the telephone device including the parent device and the child device as described above.

The operation will be described below. As shown in FIG. 8, when a call is waiting, an alert signal 2 is given to notify that a third party has called from the telephone line 21.
A dual tone signal composed of 130 Hz and 2750 Hz signals is input (S32). Alert signal detection means 2
When 3 detects the signal, the ACK signal sending means 24 automatically sends an ACK signal to the telephone line 21 informing that the alert signal has been detected (S33).

On the other hand, in order to display the telephone number and name of the third party on the display device 35 of the slave unit, data is transmitted from the master unit to the slave unit via ANT1 and ANT2, but the slave unit is in a call state. Therefore, when the data is suddenly transmitted, the data sound is heard as noise from the speaker 38 of the slave. Therefore, before transmitting the data, data of a single frequency (300 Hz, time width 100 ms × 2 times) that does not sound like noise is transmitted to the slave unit (S34), and the slave unit which detects this transmits the reception mute (S36). ). That is, when the child device receives the data from the parent device, the child device control means 36 causes the mute circuit 4 to operate.
3a is instructed, and the mute state is set so that the reception signal is not output to the speaker 38.

After that, the parent machine transmits the data of the name and the telephone number to the child machine (S35), but since the child machine mutes the reception, the data sound is not heard as noise.
The display device 35 can display the telephone number and the name. After that, when the slave unit finishes receiving the data, the mute is released and the communication state is restored (S37).

According to the above-described embodiment, in the telephone device including the master unit and the slave unit, it is possible to prevent the data sound from leaking from the speaker of the slave unit as noise when displaying the display during call waiting by the slave unit. You can

(Fourth Embodiment) The fourth embodiment of the present invention will be described below. The configuration of the main part of the telephone device according to the embodiment of the present invention is similar to that shown in FIG. FIG. 9 is a flowchart showing an embodiment of the present invention.

The operation will be described below. As shown in FIG. 9, as an alert signal for notifying that a third party has called from the telephone line 1 during call waiting, 21
A dual tone signal composed of 30 Hz and 2750 Hz signals is input. Alert signal detection means 2 is 2130H
When the z signal and the 2750 Hz signal are simultaneously detected for 40 ms (S21), the mute control means 5 immediately mutes the transmitter circuit 10 (S22). Here, at the time when the alert signal detecting means 2 first detects and outputs,
The detected signal may not be a true alert signal, but a voice malfunction due to a transmission signal.

Then, the alert signal detection operation is continued even after the transmission mute, and when the 2130 Hz signal and the 2750 Hz signal are simultaneously detected for a predetermined time (80 ms ± 5 ms), it is a true alert signal. Assuming that there is, an ACK signal sending means 3 automatically sends an ACK signal to the telephone line 1 informing that the alert signal has been detected (S23). This ACK signal is composed of frequencies of 1633 Hz and 941 Hz and has a time width of 60 ms ± 5 ms.

On the other hand, the above-mentioned 2130 Hz signal and 275
If the 0 Hz signal cannot be continuously detected for a predetermined time (80 ms ± 5 ms), the mute control means 5 immediately cancels the mute of the transmitting circuit 10 (S24) and returns to the alert signal waiting state (S21). For example, even if the transmission signal includes a frequency component close to the alert signal and the alert signal detection unit 2 detects and outputs the signal, the alert signal detection unit 2 is activated after the transmission mute is applied.
Since the detection output of is lost, 10
After a few ms, the absence of alert signal is confirmed.

By immediately muting the transmitting circuit 10 in this manner, it is determined whether the signal detected by the alert signal detecting means 2 is a true alert signal or a malfunction due to a voice signal to be transmitted. can do.
Therefore, even if the voice signal to be transmitted contains a frequency component close to the alert signal, it is not erroneously detected as an alert signal, and even if the frequency component close to the alert signal is detected first Even if the mute is applied, the mute is canceled after 10 ms when the transmission mute is applied, so that the call is hardly affected.

After sending the ACK signal, the calling party information detecting means 4
The caller information coming from the telephone line 1 as shown in FIG. 93 is detected (S25) and stored in the storage device 6 (S2).
6). If the detection is not completed by the caller information detecting means 4, the process returns to S26 to continue storing the caller information (S).
27). If the caller information detection means 4 has completed the detection, the mute control means 5 cancels the mute set in the transmitting circuit 10 (S28) to restart the call, and the display device 7 displays the caller information. Is displayed (S29).

After that, if there is a hooking input, the call partner is switched by the exchange (S30), and the storage device 6
The information indicating that the call is completed is written in the caller information stored in (S31).

According to the above-described embodiment, it is possible to prevent the output of the ACK signal to the line during the call due to the erroneous detection of the transmitted voice signal as the alert signal at the time of call waiting, and the call by the mute. The break time is 1-2
It will be possible to reduce from seconds to 10 or more ms that does not hinder the call.

[0055]

As described above, according to the present invention, the alert signal detecting means for detecting the alert signal input from the central office when a call is made from a third party during a call, and the signal comes from a telephone line. A calling party information detecting means for detecting calling party information and a mute control means for muting the calling circuit when receiving the calling party information issued by the central office after the alert signal is sent are provided. As a result, it becomes possible to detect caller information that arrives during call waiting so as not to be destroyed by a voice signal or the like, and the caller information can be visually recognized by the display device even during a call.

Further, a base unit control means for storing the calling party information detected by the calling party information detecting means in a storage device,
A master unit having a caller information transmitting means for transmitting the stored caller information as a caller information signal, and a calling unit for receiving the caller information signal from the master unit and detecting the caller information. By including the cordless handset having the caller information receiving means, the caller information can be displayed on the display device on the cordless handset side.
The called party on the slave side can visually recognize the calling party information.

Further, the master unit control means receives from the slave unit response information indicating whether or not the slave unit responded to a call from another caller, and stores it in the storage device. Since it is possible to display the caller information and response information, it is possible to easily recognize the caller who is not responding and to easily determine which caller to call again. It is possible to realize a telephone device capable of

Further, by transmitting the mute command data from the base unit to the handset and transmitting the caller information from the base unit to the handset while the handset is muting the reception, the handset The data sound is never heard as noise.

Further, when the signal detecting means for detecting the frequency component of the alert signal detects the signal, the mute start controlling means for controlling the mute circuit to stop the output from the transmitting circuit, and the signal detecting means detect the signal. If the signal continues to be detected for a predetermined period of time after being detected, the signal is recognized as an alert signal, and the confirmation signal transmission control means for transmitting the confirmation signal to the confirmation signal transmission means and the signal detection means detect the signal. Whether or not the detected signal is a true alert signal is determined by the configuration including the mute release control means for releasing the mute state of the mute circuit when the signal is not continuously detected for a predetermined time after the detection. It is possible to make a determination and prevent a malfunction due to a voice signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a telephone device according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the telephone device according to the first embodiment.

FIG. 3 is a data diagram showing an example of caller information in the telephone device according to the first embodiment.

FIG. 4 is an explanatory diagram showing a state in which caller information and response information are displayed on a display device in the telephone device according to the first embodiment.

FIG. 5 is a flowchart for explaining the operation of the telephone device according to the second embodiment of the present invention.

FIG. 6 is a block diagram showing a telephone device according to the second embodiment.

FIG. 7 is a block diagram showing a telephone device according to a third embodiment of the present invention.

FIG. 8 is a timing chart showing the third embodiment.

FIG. 9 is a flowchart showing a fourth embodiment of the present invention.

FIG. 10 is an explanatory diagram for explaining call waiting.

[Explanation of symbols]

1,21 telephone lines 2,23 Alert signal detection means 3,24 ACK signal sending means 4,25 Caller information detection means 5,26 Mute control means 6,27 storage device 7,35 Display device 8 Control means 9,30 interface 10,31 Transmission circuit 11,32 Receiver circuit 12 handsets 13 Hook switch 22 Base unit 28 Caller information transmission means 29 Parent device control means 33 cordless handset 34 Caller information receiving means 36 Remote unit control means 37 microphone 38 speakers ANT1, ANT2 antenna

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-199304 (JP, A) JP-A-6-85890 (JP, A) JP-A-3-83436 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04M 1/00 H04M 1/24-1/62 H04M 1/66-1/82 H04M 3/42-3/58

Claims (4)

(57) [Claims] 1. A telephone device comprising a master unit connected to a telephone line and a slave unit capable of wireless communication with the master unit, wherein the master unit sends a voice signal to the telephone line. A speech circuit, a reception circuit for receiving a voice signal from a telephone line, an alert signal detection means for detecting an alert signal input from a central exchange when a call is made from a third party during a call, and a telephone line Caller information detection means for detecting the caller information coming from the device, and a mute control means for muting the calling circuit when receiving the caller information issued by the central office after the alert signal is sent. A master unit control unit for storing the caller information detected by the caller information detection unit in a storage device; and a mute command data for causing the slave unit to mute the reception , , Leave the gap above And a caller information transmitting means for transmitting the stored caller information to the slave unit, wherein the slave unit detects the data transmitted from the master unit .
Immediately over the reception mute, next to receive calling party information signals from the base unit, that a calling party information receiving means for canceling the reception mute from the completion of the reception of the calling party information Characteristic telephone device. 2. The mute control means mutes the speech transmission circuit when the alert signal detecting means detects a signal of a frequency component of the alert signal, and the alert signal detecting means detects the signal. If the signal continues to be detected for a predetermined time after that, after that, the caller information detection means is caused to detect the caller information by muting, and after the alert signal detection means detects the signal. The telephone device according to claim 1, wherein the mute is released when the signal is not continuously detected for a predetermined time. 3. A telephone device comprising a master unit connected to a telephone line and a slave unit capable of wireless communication between the master unit and the master unit, wherein the master unit is called by a third party during a call. When there is an alert signal, the alert signal detection step to detect the alert signal input from the central office, the caller information detection step to detect the caller information coming from the telephone line, and after the alert signal is sent A mute control step of muting the calling circuit when receiving the caller information issued by the central office switch, and a master unit control step of storing the caller information detected in the caller information detection step in a storage device If, transmits the mute instruction data for giving multiplying the reception mute handset to handset, then Toka calling party information transmitting step of transmitting the calling party information which is the storage spaced between the handset Made, the child machine, be to detect the data sent from the base unit
The caller information receiving step of first muting the call, then receiving the caller information signal from the master unit, and canceling the call mute after finishing receiving the caller information. And method of receiving caller information. 4. The mute control step mutes the transmitting circuit at the time of detecting the signal of the frequency component of the alert signal in the alert signal detecting step, and detects the signal in the alert signal detecting step. If the signal continues to be detected for a predetermined time after that, after that, mute is subsequently performed to cause the calling party information detection step to detect calling party information, and after the alert signal detection step detects the signal. The telephone device according to claim 3 , wherein the mute is released when the signal is not continuously detected for a predetermined time.