JPH02305133A - Privacy call communication system - Google Patents

Abstract

PURPOSE:To decrease number of installed privacy call devices by providing a prescribed traffic number of privacy call devices to a digital exchange and connecting a relay line between a telephone set and an opposite telephone set via a privacy call device. CONSTITUTION:A digital exchange 1 is provided with a privacy call communication pool trunk 6, a privacy call device 7 and a privacy call communication pool trunk 8 all connected in series. A voice signal (c) from a telephone terminal 2(1) is inputted to the privacy call device 7 via the privacy call communication pool trunk 6 and converted into a cryptographic signal (d). The cryptographic signal (d) is inputted to a relay line trunk 5(1) via the privacy call communication pool trunk 8 and reaches a digital exchange to which opposite telephone set belongs via a relay line 4(1). Thus, number of installation set of the privacy call devices is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a secure communication system via a digital exchange, and particularly to a pool system for secure communication devices.

[Conventional technology]

A privacy device is a device that prevents the contents of a call from being overheard by other telephones connected to the same telephone line. Confidential communication is performed using this confidential communication device.

In the conventional confidential communication system, a confidential communication device is provided corresponding to each telephone terminal, and the confidential communication device converts the audio signal/encrypted signal, and this encrypted communication is performed between the confidential communication devices of the telephone terminals. It had achieved its purpose.

[Problem to be solved by the invention]

The conventional confidential communication method described above is a method in which a confidential communication device is provided corresponding to each telephone terminal, and encrypted communication is performed between the confidential communication devices, and communication is performed via the confidential communication device even in normal communication, not confidential communication. This method has the disadvantage that a large number of telephone terminals need to be equipped with secret communication devices, regardless of the traffic.

The purpose of this invention is to solve the above-mentioned conventional problems.
To provide a confidential communication system capable of performing confidential communication while minimizing the number of installed confidential communication devices.

[Means to solve the problem]

The confidential communication system of the present invention is provided with a predetermined number of confidential communication devices for converting voice signals into encrypted signals or from encrypted signals into voice signals in a digital exchange, and receives a confidential communication request signal from a telephone terminal belonging to the digital exchange. Sometimes, this telephone terminal and the trunk line of the other party's telephone terminal are connected via the confidential communication device to enable confidential communication.

〔Example〕

Embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram for explaining a confidential communication system according to an embodiment of the present invention.

Digital exchange I has telephone terminals 2 (1) to 2 (b).
extension circuits 3 (1) to 3 (n), and trunk line 4 (
1) to 4 (m) trunk trunk 5(1) to 5 (m)
) are connected. Further, this digital exchange 1 is provided with a confidential communication pool trunk 6, a confidential communication device 7, and a confidential communication pool trunk 8 connected in series.

When there is a confidential communication request signal a from any of the telephone terminals 2(1) to 2(n), the digital exchange 1 transmits the confidential communication request signal a to the telephone terminal 2(1) (or to
2(n)) and the private communication pool trunk 6, and the trunk line trunk 5(1) (or , ~5(n+)) and the private communication pool trunk 8. In addition, the digital exchange 1 has a trunk line trunk 5 (IN or ~5 (
ra)) and the confidential communication pool trunk 8, it also has the function of sending a signal indicating the telephone terminal number and confidential communication from the trunk line trunk 5 (IN or ~5(n+)). . Note that the digital exchange 1 performs call detection,
Response, reception 2 number translation 2 Judgment whether or not the episode is in progress.

It also has general functions as a digital exchange, such as calling, response detection 9, call path closure, end of call detection, and call path recovery.

The confidential communication pool trunk 6 is an interface circuit compatible with the normal audio signal C.

The confidential communication device 7 has a function of converting the audio signal C from the confidential communication pool trunk 6 into an encrypted signal d, and a function of converting the encrypted signal d into an audio signal C.

The confidential communication pool trunk 8 is an interface circuit compatible with the encrypted signal d.

Next, the confidential communication operation of this embodiment will be explained.

Telephone terminal 2(1) upon request from telephone terminal 2(1)
and a telephone terminal belonging to the digital exchange to which trunk trunk 5 (1) is connected, and to the digital exchange to which telephone terminal 2 (n) and trunk trunk 5 (m) are connected. When performing normal telephone communication with the telephone terminal to which it belongs, the telephone terminal 2 (1) sends out a secret communication request signal a along with a calling signal e, and the telephone terminal 2
A calling signal f is sent from (n).

The digital exchange l receives the calling signal e and the confidential communication request signal a via the extension circuit 3(1),
1) and the private communication pool trunk 6,
The private communication pool trunk 8 and trunk line trunk 5(1) are connected. At the same time, the digital exchange 1 sends the number of the telephone terminal 2(1) and a signal indicating that it is a confidential communication from the trunk trunk 5(I).

Based on the signal, the other party's digital exchange connected to the trunk trunk 5(1) connects the private communication pool trunk installed in the digital exchange that supports encrypted signals and the trunk 4(1) of the trunk trunk 5(1). 1), and the other party's telephone terminal is connected to the confidential communication pool trunk that supports voice signals and is connected to the confidential communication pool trunk via the confidential communication device. As a result, the communication path between this other party's telephone terminal and telephone terminal 2(1) is established.

The voice signal C from the telephone terminal 2(1) is input to the confidential communication device 7 via the confidential communication pool trunk 6, and is converted into the encrypted signal d. This encrypted signal d is the secret communication pool trunk 8
into trunk 5 (I) via trunk 4 (
1) to the digital exchange to which the other party's telephone terminal belongs. This encrypted signal d is sent to the other party's telephone terminal as an audio signal a via a confidential communications pool trunk compatible with encrypted signals, a secure communications device, and a confidential communications pool trunk compatible with voice signals.

The code number d' from the other party's telephone terminal is input to the confidential communication device 7 via the trunk line trunk 5 (1) and the confidential communication pool trunk 8, and becomes an audio signal a' from the confidential communication pool trunk 6 to the telephone terminal. 2(1).

Confidential communication is performed in this way.

On the other hand, the calling signal f from the telephone terminal 2(n) is received by the digital exchange 1 via the extension circuit 3(n), and the digital exchange 1 connects the extension circuit 3(n) and the trunk trunk 5.
Connect with (m). This allows normal telephone communication to be performed.

In this embodiment, the secret communication pool trunk 6.
Although only one set of 8 and secret device 7 is provided, the purpose is not limited to this. It is clear that any number of sheets can be provided corresponding to the track amount of the telephone terminals 2(1) to 2(n).

Furthermore, when there are two or more types of confidential communication devices in the network, by adding a function to select two or more types of confidential communication devices installed as common equipment, it is possible to communicate with various types of confidential communication devices from one telephone terminal. It becomes possible.

〔Effect of the invention〕

As explained above, the confidential communication system of the present invention is such that a digital exchange is provided with a predetermined number of confidential devices for converting voice signals into encrypted signals or from encrypted signals into voice signals, and communication between telephone terminals belonging to the digital exchange is When a secret communication request signal is received, this telephone terminal and the relay line of the other party's telephone terminal are connected via the secret communication device, thereby performing secret communication, so that the number of installed confidential communication devices can be reduced. As a result, the cost of the entire system can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a confidential communication system according to an embodiment of the present invention. l...Digital exchange 2(1) to 2(n)...Telephone terminals 4(1) to 4 (m)...Relay line 7...Confidential device agent Patent attorney Iwasa Yoshiyuki Digital switchboard diagram 1

Claims (1)

[Claims] (1) A digital exchange is provided with a predetermined number of traffic secret devices that convert voice signals into encrypted signals or from encrypted signals into voice signals, and when a confidential communication request signal is received from a telephone terminal belonging to this digital exchange, this telephone terminal A confidential communication system, characterized in that the confidential communication is made possible by connecting the telephone terminal and the relay line of the other party's telephone terminal via the confidential communication device.