JPH0537458A - Privacy system for cordless telephone set - Google Patents

Abstract

PURPOSE:To protect the privacy of communication by providing a channel control part at a cordless telephone set and continuously switching a used speaking channel corresponding to the blank of a voice. CONSTITUTION:For the speaking channel used for transmission/reception between a base unit 100 and a hand set 200, the blank of the speaking channel is detected corresponding to the present/blank of voice signals by channel control parts 150 and 250 according to the present/absent state of voice signals from transmission control parts 152 and 252, and the speaking channel is switched to the idle channel. For example, when the channel control part 150 detects the state of stopping transmission and the state of stopping reception from the transmission control part 152 and a reception control part 151 through signal lines 152a and 151b, one of unused channels is selected while referring to a channel state table and transmitted through signal lines 150b and 150c to the transmission control part 152 and the reception control part 151. The transmission control part 152 transmits the selected channel to the hand set 200 while using a control channel A or B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secret communication system for cordless telephones, and more particularly to a function for switching a communication channel so that a cordless telephone has a function for preventing leakage of communication contents.

[0002]

2. Description of the Related Art Cordless telephones have come to be used due to the revision of the Telecommunications Business Law and the Radio Law. Since this type of telephone station fixedly uses one of 87 channels between the parent telephone and the child telephone, it is fixedly used when a third party intercepts the channel in use. It leads to leakage.

As a conventional technique, a method of encrypting and transmitting a voice signal is also known, but a circuit for encryption and decryption is too costly and not practical.

[0004]

The conventional method of managing a call channel in a cordless telephone does not have a function of preventing interception of a call channel by a third party.
It is only reflected in the channel selection to be used later by the function of detecting the channel used by another phone when the telephone is started to be used, and when the unused channel is determined, the used channel remains fixed for the duration of the call. ..

A method for encrypting and transmitting a voice signal is also known, but a circuit for encryption and decryption is too expensive and not practical.

The present invention has been made in view of the above-mentioned conventional circumstances, and therefore, an object of the present invention is to provide a novel cordless telephone secret communication system capable of solving the above problems inherent in the conventional technology. To do.

[0007]

In order to achieve the above object, in the cordless telephone secret telephone system according to the present invention, the conventional cordless telephone is provided with a channel control function for controlling a call channel, so that a master telephone can be obtained. It is possible to prevent the third party from intercepting the used channel by matching the call channel decided at the beginning of the call between the mobile phone and the slave phone to the break of the audio signal.

According to the present invention, the presence / absence of a voice signal is detected by using a transmission control unit for transmitting a voice signal to the other party's telephone as a radio wave and a reception control unit for converting the radio wave transmitted from the other party's telephone into a voice signal. By passing it to the channel controller,
The channel control unit detects the vacant state of the call channel at the time of the break of the voice signal and sends the vacant channel to the transmission control unit or the reception control unit, so that the vacancy of the next voice signal is maintained. Make a call using the channel.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the accompanying drawings with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, the parent telephone 100 and the child telephone 200 communicate with each other through their respective antennas 120 and 220.

In the master telephone 100, the office line control unit 10
5 controls the office line 1. The reception information from the station line 1 is sent to the transmission control unit 152 through the signal line 105a, and the transmission control unit 152 outputs the reception information from the station line 1 to the signal line 152.
It outputs to the antenna 120 via b. Also, the transmission control unit 1
Reference numeral 52 sends out a "transmitting" state to the channel control unit 150 via the signal line 152a in order to control the transmission / reception channel. In the channel control unit 150, the “receiving” signal line 151b from the reception control unit 151 is received by the signal line 152a.
The channel number to be used for the call is determined together with the "transmission" from the above, and the channel number is transmitted using the signal line 150b and the signal line 150c. That is, at the time of transmission, the signal line 1
50c is used to set the transmission channel number to the transmission control unit 152.
The reception channel number is transmitted to the reception control unit 151 by using the signal line 150b during reception.

The information sent from the antenna 220 of the slave telephone 200 is received by the antenna 120, and the signal line 1 is received.
It is received by the reception control unit 151 via 20a. The reception control unit 151 sends the existence of the reception information to the channel control unit 150 via the signal line 151b, and sets it as a condition for determining the channel to be used. That is, when there is a call from the slave telephone 200, the used channel is not switched. From the reception control unit 151, the telephone line of the slave 200 is connected to the signal line 15
The call is sent to the other party via the office line 1 via the office line 1c.

Information is transmitted from the sub-telephone set 200 through the antenna 220. Reception information is sent to the reception control unit 251 via the signal line 220a from the antenna 220. Call information is sent to the handset 201 via the signal line 251a. Channel number information is sent to the reception control unit 251 through the signal line 220a from the antenna 220.
Channel number information is taken out by the channel controller 250, and the used channel is transmitted using the signal lines 250b and 250c. The reception control unit 251 performs reception on the channel designated by the signal line 250b, and the transmission control unit 252 transmits the transmission information from the signal line 202b according to the channel designated by the signal line 250c.
To the antenna 220 via.

In the master telephone 100, the information line 102a from the transmitter 102 is a path of a transmission signal when only the master telephone 100 is used, and the information line 102b is the master telephone 1.
This is a path of a transmission signal at the time of a so-called extension call between 00 and the slave telephone 200.

The information line 105b to the handset 101 is a path of a reception signal when only the parent telephone 100 is used.
The information line 151a is a path of a reception signal during a call between the parent phone 100 and the child phone 200, that is, an extension call.

FIG. 2 shows the channel controller 15 in FIG.
It is a channel management table used for realizing the functions of 0 and 250.

In FIG. 2, channels A and B are control channels, and channel numbers 1-87 are used for telephone calls. A channel whose status is shown by "1" is in use.

In FIG. 1, the channel controller 150 is
From the transmission control unit 152 and the reception control unit 151 to the signal line 1
When the "state not being transmitted" and the "state not being received" are detected via 52a and 151b, one is selected from the unused channels by referring to the channel state table (FIG. 2), and the transmission controller 152 , To the reception control unit 151 via the respective signal lines 150b and 150c. The transmission control unit 152 sends the selected channel to the slave telephone 200 using the control channel A or B.

[0020]

As described above, according to the present invention, by providing means for appropriately switching the call channel used in the cordless telephone, it is possible to prevent the third party from intercepting the call channel and to improve the call content. It is possible to prevent leakage.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a channel management table diagram used by the channel control units 150 and 250 of FIG. 1 for channel management.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Local line control part 100 ... Master phone 200 ... Slave phone 101, 201 ... Receiver 102, 202 ... Transmitter 151, 251, ... Reception control part 152, 252 ... Transmission control part 120, 220 ... Transmission / reception antenna 150, 250 ... Channel controller

Claims (1)

Claims: 1. A cordless telephone that transmits and receives an audio signal using radio waves between a parent telephone and a child telephone, and is used for transmission and reception between the parent telephone and the child telephone. A cordless telephone secret phone characterized by detecting a vacant call channel in the channel control unit according to the presence / absence of a voice signal from the transmission control unit and the reception control unit and detecting the vacancy of the communication channel, and switching to the vacant channel. method.