JPH06232964A - Secrecy system in trunk line speech transfer - Google Patents

Abstract

PURPOSE:To simply provide a secrecy function of inter-extension mutual speech for a trunk line by inserting a voice processing circuit to each telephone set of the simple home telephone system. CONSTITUTION:In the simple home telephone system in which plural telephone sets 21, 22 are connected in parallel with a trunk line, each telephone set is provided with a voice processing circuit having a voice conversion and decoding function removably. In the case of talking with the trunk line, the voice processing circuit 205 is removed from the talking path to implement talking similarly to the usual talking and in the case of talking between the telephone sets, the voice processing circuit 205 is inserted to the speech path, then a transmission voice signal from a sender side telephone set is converted into a waveform signal representing no meaning and sent to a line 1. Then the waveform signal whose meaning is not clear received by the receiver side telephone set is decoded into the original voice signal by the voice processing circuit 205 to attain talking. In this case, since the waveform signal whose meaning is not clear is sent to the trunk line, no understanding performance is in existence and secrecy is kept for the trunk line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for secretly talking to a station line between telephones of a simplified home telephone in which a plurality of telephones are connected in parallel to the station line.

[0002]

2. Description of the Related Art In a conventional simplified home telephone, a plurality of telephones are connected in parallel to a station line. Therefore, when an incoming call from a station line is answered by one telephone and transferred to another telephone, Since two telephones are connected in parallel, a three-party call connection is established.

[0003]

According to the above-mentioned prior art, since a three-way call connection is made between a station line and two telephones in mutual call during transfer, the mutual call voice between the two telephones is transmitted. The problem is that you can hear the line. Therefore, it is an object of the present invention to keep the mutual call between the above-mentioned telephones secret from the station line.

[0004]

[Means for Solving the Problems] A voice conversion / restoration circuit having the same function is detachably provided in the call circuits of all the telephones constituting the simple home telephone, and the above-mentioned voice conversion / restoration circuit is excluded in the case of a station line call. In the case of a telephone call between telephones, the voice conversion / restoration circuit is inserted.

[0005]

According to the present invention, when a telephone call is transmitted between telephones, the voice is converted to a station line and is incomprehensible as it is. The voice converted on the side is restored to the original voice on the receiving side, so that a normal call can be performed. That is, it is possible to add a confidential communication function to the local line of the communication voice between the telephones.

[0006]

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

In FIG. 1, each telephone is connected in parallel to a central office line, and the configuration inside each telephone is the same.

Reference numeral 1 is a connection line to an office line, 21 and 22 are telephones according to the embodiment of the present invention, 201 is a line control circuit, 202 is a dial circuit, 203 is a dial, and 204 is a call including a 2-wire / 1000-line conversion circuit. A circuit, 205 is a voice processing circuit, 20
51 is a voice conversion unit, 2052 is a voice restoration unit, 2053 and 2054 are switching control units, 206 is a handset, 207 is an incoming call detection circuit, 208 is a CPU, 209 is a sound source, 210
Is a speaker, 211 is a data input / output circuit, and 212 is an operation unit including keys, hook switches, display lamps, and the like.

When there is an incoming call from the central office line, the telephone sets 21 and 22
In, the incoming call detection circuit 207 operates and sends incoming call detection information to the CPU 208. The CPU 208 drives the sound source 209 and sends out a local line ring tone from the speaker 210. For example, when the handset 21 raises the handset 206 and responds, the hook switch in the operation unit 212 of the handset 21 operates and C
The hook-off information is sent to the PU 208, and the CPU 208 receives this information and sends a response instruction to the line control circuit 201, whereby the line control circuit 201 closes the DC loop with respect to the office line, and the telephone 21 is connected to the station. The line is in communication. At this time, the CPU 208 does not send control information to the voice processing circuit 205 because it determines that the call is a local line call.
Since the connection direction at 54 is the direct side and voice processing is not performed, a normal call can be performed between the station line and the telephone 21.

Next, when transferring from the telephone 21 to the telephone 22, after pushing the internal call button on the operation unit 212 of the telephone 21, the extension telephone number button (the telephone 2
In the case of a telephone, it is not necessary to press the extension telephone number button), the CPU 208 detects the pressing of the internal call button, sends control information to the voice processing circuit 205, and the switching control unit 2
053 and 2054 are switched and controlled, and the voice processing circuit 205 is inserted between the communication circuit 204 and the handset 206 to perform voice processing.

Under the control of the CPU 208, extension call and extension number data are transmitted from the data input / output circuit 211 to the line 1.
Send to. In the telephone set 22, the data input / output circuit 211 detects extension calling and extension number data from the telephone set 21 and sends the information to the CPU 208. If the information is addressed to the own telephone, the CPU 208 drives the sound source 209 and sends an extension call signal from the speaker 210. Also CPU 208
Receives the extension call information, sends control information to the voice processing circuit 205, and inserts the voice processing circuit 205 between the call circuit 204 and the handset 206 to perform voice processing as in the case of the telephone 21. .

By the voice processing circuit insertion processing, the extension mutual call between the telephone 21 and the telephone 22 is inserted in the voice processing circuit 205 in the telephone call path of either telephone, and the transmission path from the telephone 21 to the telephone 22 shown below is inserted. Is configured.

Telephone 21 (speaker 206-speech converter 2051-speech processor 2051-speech circuit 204-dial circuit 202-line control circuit 201) -line 1-telephone 22 (line control circuit 201-dial circuit 202-) Call circuit 204-Voice restoration unit 2052 of voice processing circuit 205
-Handset 206) The transmission path from the telephone set 22 to the telephone set 21 has the same path as the telephone line 21 and the telephone set 22 are replaced with each other.

The voice transmitted from the telephone set 21 (22) is subjected to conversion processing by the voice conversion unit 2051 of the telephone set 21 (22) by the above-mentioned path and becomes a waveform signal whose meaning is unknown, and is sent to the telephone set 22 (21) via the line 1. To be done. Telephone 22 (2
In 1), the voice restoration unit 2052 restores the waveform signal of which the meaning is unknown to the original voice.
It becomes possible to call each other.

At this time, the voices flowing from the telephones 21 and 22 to the line 1 are the above-mentioned waveform signals of which the meaning is unknown and converted by the respective voice converting units 2051 and are not intelligible. The person cannot understand the content of the call.

Ordinary voice from the office line is transmitted to the telephone 21,
The telephone 21 and the telephone 22 even during mutual communication between the telephones 22.
However, since the voice restoration unit 2052 of the voice processing circuit 205 is inserted in the receiving path of any of the telephones 21 and 22, the voice from the relevant office line becomes an unclear signal (voice restoration unit 2052). Processing is performed by the voice conversion unit 205.
Since it is the inverse conversion processing of the audio signal converted in 1, if the normal audio undergoes the processing (inverse conversion processing) in the audio restoration unit 2052, it becomes an incomprehensible signal. As a result, it is a secret story between the station line and the telephone 21 or the telephone 22.

Therefore, it is a secret talk between the telephone 21 and the telephone 22 and the office line during mutual communication.

After the telephone mutual call, when the handset 206 of the office line transfer source telephone 21 hooks on the hook, the operation unit 2
The hook switch in 12 is the on-hook information of the CPU 20.
8, the CPU 208 opens the direct current loop of the line control circuit 201 and sets the call path of the telephone 21 to the line 1
Disconnect from.

On the basis of the on-hook information from the hook switch, the CPU 208 causes the data input / output circuit 211 to transfer the destination telephone 22 via the line 1 to the destination telephone 22.
Send on-hook information for. In the telephone 22, the data input / output circuit 211 receives the on-hook information and the CPU 20
8, the CPU 208 instructs the voice processing circuit 205 to switch the switching control units 2053 and 2054 to the direct communication side, whereby the communication circuit 204 is directly connected to the handset 206.

As a result, the telephone line and the telephone set 22 are connected by an ordinary circuit that does not pass through the voice conversion unit 2051 and the voice restoration unit 2052 of the voice processing circuit 205, so that the telephone set 2 is connected.
No. 2 enables normal communication with the central line.

[0021]

EFFECT OF THE INVENTION A simple home telephone in which telephones are simply connected in parallel to a central line is advantageous in that it is economical because of its simple structure, but it has a major drawback in that it does not have a confidential function when transferring a call. Met. According to the present invention, the confidential communication function at the time of transfer can be economically realized simply by adding the voice processing circuit in the telephone.

[Brief description of drawings]

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

[Explanation of symbols]

1 ... Line 21, 22, ... Telephone 201, Line control circuit 204 ... Call circuit 205 ... Voice processing circuit 2051 ... Voice conversion unit 2052 ... Voice restoration unit 206 ... Handset 208 ... CPU

Claims (1)

[Claims] 1. In a telephone device in which a plurality of telephones are connected in parallel to a station line, a voice conversion / restoration circuit is removably provided in a call path of the plurality of telephones to make a call to the station line. Makes a call in the same manner as a normal call except for the voice conversion / restoration circuit. A secret communication method when transferring to a station line call, which is inserted into the call path so that only the above telephones can talk with each other and the voice signal flowing out to the station line becomes an incomprehensible voice signal.