JPS60176355A - Privacy line interrupting system - Google Patents

Abstract

PURPOSE:To make it possible that a subscriber having a high priority level dials a password number to perform forcibly an interrupt call to an exchange channel, which declarative sentences pass, for privacy communication between subscribers. CONSTITUTION:Subscribers 1 and 2 are switched and connected by an exchange 7, and the line between them is made secret by privacy devices 4, 14, 5, and 15, but declarative sentences pass the channel of the exchange 7. If a subscriber 3 having a priority level higher than those of subscribers 1 and 2 hooks on the handset temporarily and dials the password number after he calls the subscriber 1 or 2 and is busy, the exchange 7 discriminates precedence, and the exchange 7 performs forcibly bridge cut off because the subscriber 3 has a higher priority level.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a secret communication system, and more particularly to a secret line interrupt method that enables forcible interruption to a secret busy line.

(b) Conventional technology and problems The prior art will be explained with reference to the drawings.

FIG. 1 is a block diagram of a conventional terminal concealment system including an exchange, and shows an example of a secure communication system.

In the figure, subscribers 1 and 2 are exchange-connected by an exchange 7, and secure transmission is performed by secure devices 4 and 5. When the subscriber 3 makes a forced interruption 9 to the communication path 8, there is a drawback that the interruption call is impossible because the encryption rules with the secret devices 4 and 5 do not match.

(C) Purpose of the Invention In view of the above-mentioned drawbacks of the conventional art, an object of the present invention is to provide a system in which a high-priority subscriber can forcefully interrupt a confidential communication between low-priority subscribers. shall be.

(d) Structure and object of the invention According to the present invention, it is possible to prevent a third party from accessing a busy line by using a secure line switching system that conceals only one part of the transmission line between an exchange and a subscriber. This is a system in which a subscriber makes an interrupt call, and the exchange has a determination circuit that determines the subscriber priority registered in advance based on the output of the subscriber's PIN number detection circuit, and temporarily stores the busy line connection information. A secret line interrupt method characterized in that a save memory for saving and a change circuit for changing the line connection are provided, and when the determination circuit determines that the priority is high, the change circuit performs a forced interrupt connection. This is achieved by providing

[el　Embodiments of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

In the top view, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 2 shows a block diagram for explaining the outline of the present invention.

In the figure, subscribers 1 and 2 are exchanged and connected by an exchange 7, and the lines are kept confidential by concealment devices 14.4 and 15,5. Subscriber 3, whose priority is higher than subscribers 1 and 2, issues forced interruption 11 to communication path 10.

Since the line is kept confidential, the information is in plain text in the exchange 7, so if the line is busy, the subscriber 3 will temporarily terminate the line and dial the PIN again to determine the subscriber's priority. This feature allows for forced interruption calls in certain situations.

FIG. 3 is a line system diagram used to explain the present invention.

FIG. 4 shows a block diagram of the main parts of an exchange using the secret line interruption method of the present invention.

In FIG. 3, subscribers 20 and 21 are subscribers to the private branch exchange 26, and the transmitted signal is digitally encoded by the vocoder device 28, encrypted by the secret device 33, and modulated into an analog signal by the modem device 37. Sent to the transmission path.

Time division switch (hereinafter abbreviated as TD-M).

After the received signal of 39 is demodulated into a digital signal by the modulation/demodulation device 35, the code is decrypted by the secret device 31 and the signal is transmitted to the TDM3.
9, time-sharing exchange is performed.

The lines of subscribers 22 and 23 are exactly the same. TDM39
The voice signals of the subscribers 24 and 25 of the station where is installed are digitally encoded by the vocoder device 30 via the private branch exchange 28, and then input to the TDM 39. The interrupt function of the private branch exchange is used to interrupt the subscriber within the own office. Interruption to the secret line is performed using the interrupt function of the TDM 39.

In FIG. 4, received data RD from a secret device or a vocoder device is subjected to frame synchronization by a frame synchronization circuit 40, and then received frame data such as dial pulses are extracted by a frame synchronization information extraction circuit 42, and then received by a line control unit 44.
Send to.

To exchange data in a time-division manner, a time-division switch (hereinafter referred to as 'r)
At step 48 (abbreviated as sw), the following address is exchanged with the write address. This operation is performed under the control of a central processing unit (hereinafter abbreviated as CPU) 49 based on the received frame data received by the line control unit 44. Data read according to successive addresses is
For example, it is sent to the transmission frame data creation unit 53 and
It is combined with the transmission frame data from the IF control unit 44 and sent to the secret device or vocoder device as transmission data SD.

In order to make a forced interruption call in such a device, the procedure described below is used.

If a subscriber dials a call to the other subscriber and the subscriber wants to make a forced interruption call to the busy line, the subscriber must hang up the phone and then re-enter the PIN number known only to the interrupting subscriber. Then dial the telephone number of the subscriber you want to talk to. The password is detected by the password detection circuit 45 of the TDM 39, and is detected by a determination circuit (consisting of a CPU 49 and a ROM 50) that compares and determines the priority of the pre-registered subscriber with whom you wish to make a call and the interrupting subscriber. When the comparison is made and it is determined that the priority of the interrupting subscriber is high, the CPU 49 saves the subsequent address of the currently active line from the subsequent address storage register 46 to the save memory 47, and then saves the subsequent address of the currently active line to the save memory 47. By changing the addressing of TSW 48 via TSW 44, an interrupt call can be made.

A signal tone indicating that an interruption is in progress is sent to the subscriber of the line being evacuated. After the interruption ends, the contents of the save memory 47 are returned to the successive address storage register 46, and the original call can be resumed. If the output of the determination circuit determines that the priority of the comparison result is low, a signal indicating that an interrupt is not possible is sent to the interrupt subscriber.

(fl Effects of the Invention As explained in detail above, according to the secret line interruption method of the present invention, forced interruption calls are made when it is necessary to communicate with a predetermined priority in a specific social organization, etc.) This allows valuable hidden lines to be operated more flexibly.

[Brief explanation of drawings]

Figure 1 is a block diagram of the terminal concealment system including the exchange, Figure 2
The figure is a block diagram for explaining the outline of the present invention. FIG. 3 is a line system diagram used to explain the present invention, and FIG. 4 is a block diagram of the essential parts of an exchange using the secret line interruption method of the present invention. In the figure, 20 to 25 are subscribers, 39 is an exchange (time division exchange), 45 is a password detection circuit, 46 is a register for storing successive addresses, 47 is a save memory, 49 is a central processing unit (CPU), and 50 is a ROM. , RD is received data, SD
indicates transmission data. Figure 1 Figure 2 Figure 3 Sword Figure 4

Claims (1)

[Claims] A system in which a third party subscriber interrupts a busy line and makes a call by using a hidden line switching system that conceals only the transmission path between the exchange and the subscriber, and the subscriber a determination circuit that determines a pre-registered subscriber priority based on the output of a personal identification number detection circuit; a save memory that temporarily saves the busy line connection information; and a change circuit that changes the line connection; A secret line interrupt method characterized in that when the determination circuit determines that the priority is high, the change circuit performs a forced interrupt connection.