JPH0156584B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention provides a method for carrying out secret communication between subscriber terminals housed in opposing electronic exchanges by using a common secret device installed in each electronic exchange. Concerning the secret call methods that can be used.

(b) Background of the technology A digital concealing device means that when transmitting audio, it is encoded by a voice encoding device to become a digital signal, scrambled with a certain regularity by a concealing device, and then transmitted by a modem and modulator. , if you want to receive a confidential audio signal by converting it to an analog signal and transmitting it, follow the reverse route.
A modem converts it into a digital signal, a secret device performs day scrambling according to certain rules, and a voice encoder converts it into a speech signal.It has 4 wires for both input and output, so one device can handle the transmission side. and has a receiving side.

(c) Prior art and problems Conventionally, when subscriber terminals (hereinafter referred to as telephones) make secret calls, each telephone has a digital concealment device (hereinafter referred to as concealment device), and the line is connected by an exchange. After making the connection, the call was switched to be made via a hidden device. However, in this method, it is necessary to have a concealment device for each telephone that needs to make a secret call, so a large number of expensive concealment devices are required, and the system has the disadvantage of being expensive.

(d) Purpose of the Invention The purpose of the present invention is to eliminate the above-mentioned drawbacks, and to make it possible to use a secret device provided in each electronic exchange in common when carrying out a secret call between subscriber terminals housed in opposing electronic exchanges. The aim is to provide a confidential communication method that is possible.

(e) Structure of the Invention In order to achieve the above object, the present invention provides first and second subscriber terminals that accommodate a plurality of opposing subscriber terminals.
trunk link network of electronic exchanges,
The input and output of the digital concealment device are connected via out-of-band dial signal in/out trunks, and the first and second electronic exchanges are connected to the dial signal from the subscriber terminal on the calling side. The subscriber terminals on the calling side and the called side are each provided with connection means for secure communication via the above-mentioned out-of-band dialing signal ingress/egress trunk, digital concealment device, and out-of-band dialing signal ingress/egress trunk; (f) Embodiment of the Invention (f) Embodiment of the Invention (f) Embodiment of the Invention (f) Embodiment of the invention Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an electronic exchange according to an embodiment of the present invention.

In the figure, 1 to 3 are telephones, 4 is a line link network, 5 is a trunk link network, 6 is a communication path control device, and 7, 8, and 9 are out-of-band dial signal input/output trunks (hereinafter referred to as ODBWT) with four lines. It is connected. 10 is a secret device, 11 is an outgoing register trunk (hereinafter referred to as ORT), 12 is a signal tone trunk (hereinafter referred to as TNT), 13 is a ringing signal trunk (hereinafter referred to as RGT), and 14 is an outgoing sender trunk (hereinafter referred to as OST). ), 15 indicates a central control unit.

A case will be described in which a telephone set of one electronic exchange is used to talk to a subscriber of the other party's electronic exchange (assuming that the configuration is the same) in a normal state. When Telephone 1 makes a call and connects to ORT 11, and the program identifies the connection to the other party's electronic exchange, the digits dialed by Telephone 1 are connected to OST1.
4, the output side of the ODBWT 7, and the input side of the ODBWT 7 of the other station. At this time, the communication path between the telephone set 1 and the ODBWT 7 is prepared as a reserved path, and is switched when the transmission of the selected digits from the OST 14 is completed. At the other party's exchange
Receive the selected digits through the input side of ODBWT7,
After identifying the incoming subscriber, telephone 1 receives a TNT
12 in the opposite direction through the output and input sides of ODBWT 7 of both exchanges. Also, for incoming subscribers
A calling signal is sent from RGT13. At this time, a reserved path is prepared for the communication path between the ODBWT 7 of the other party's exchange and the called subscriber, and when the called subscriber responds, the communication path is switched to the reserved path. Only then can a call between telephone 1 and the called subscriber be made through ODBWT 7 of both exchanges, and all other trunk paths are restored. At this time, both exchangers
A four-wire connection is established between the ODBWTs 7 using a trunk line.Next, the case where it is desired to communicate via the secret device 10 will be explained. The secret device 10 has an ODBWT 8, an input/output terminal for the audio transmitting side and an input/output for the receiving side.
9 is connected to the trunk link network 5, and the identification numbers of ODBWTs 8 and 9 are not used for central office line connections, trunk line connections, or intra-office connections; for example, 8 is used on the sending side. , 9 is assigned to the receiving side. As a dial number, the first digit is 8, dial 8,
Make it possible to identify ODBWT8. The next number is a dial number that can identify the trunk ODBWT7 for the trunk line, for example, 7, and the next number is:
Set the number 9 to identify the partner station ODBWT9,
Next, enter the subscriber number of the other station. In addition, the connection program for secret calls that is provided in the call path control device 6 is identified by the above dialed numbers,
Via ODBWT8, secret device 10, ODBWT9,
ODBWT7, the other party's exchange via the trunk line
After ODBWT7, ODBWT9, hidden device 10,
Make sure to connect via ODBWT8.

Here, telephone 1 makes a call, is connected to ORT 11, and with the first dialed number 8, secret device 1
When the program identifies that the connection is to ODBWT 8 through 0, a path via ODBWT 8, secret device 10, and ODBWT 9 is prepared as a reserved path. Next dial number 7,
When the program identifies that the connection is to another electronic exchange, the digits dialed by the telephone 1 are sent through the OST 14, via the outgoing side of the ODBWT 7, to the incoming side of the ODBWT 7 of the other station.
At this time, telephone 1, ODBWT 8, concealment device 10,
The communication paths with ODBWT 9 and ODBWT 7 are prepared as reserved paths, and are switched when the transmission of the selected digits from OST 14 is completed. At the other party's exchange
Receive the selected digits through the input side of ODBWT7,
Via the channel control device 6, the program uses the first number 9 to set the ODBWT 9, the secret device 10,
After identifying the connection to the terminating subscriber via ODBWT 8 and identifying the terminating subscriber by the following digits, telephone 1 is connected in the reverse direction from TNT 12 via the egress and ingress sides of ODBWT 7 of both exchanges. to send a ringtone. A paging signal is also sent from the RGT 13 to the called subscriber. At this time, the other party's exchange
ODBWT7, ODBWT9, secret device 10,
The communication path to the terminating subscriber via the ODBWT 8 is prepared as a reserved path, and is switched to the reserved path when the terminating subscriber responds. Only then can a confidential call be made between the telephone set 1 and the called subscriber by means of the security device 10 inserted into both. At this time, the distance between the hidden device 10 and ODBWT 7 of both parties is
A 4-wire connection is made via ODBWT8 and 9.

As a result, the telephones 1, 2, and 3 connected to the electronic exchange can freely use the secret device 10 to make secret calls with the receiving subscriber. It would be good to have one. Of course, if you use them frequently, you can have several, and when you need to connect them, you can have a connection structure that allows you to slide them to find an empty one. This eliminates the need for an expensive concealment device for each telephone and allows common use, resulting in a system that can be constructed at low cost.

FIG. 2 is a block diagram of an electronic switching network according to an embodiment of the present invention.

In the figure, 20 and 21 are electronic exchanges, 22 is an electronic exchange having a trunk line connection function, 30 to 35 are secret devices, 41 to 44 are trunk lines, and 51 to 56 are telephone sets.

Now change the office number of electronic exchange 22 to 70, electronic exchange 2
The office number of 0 is 71, the office number of the electronic exchange 21 is 72, the number connected to the secret device from the telephone of each electronic exchange is 8, and the number connected to the secret device from the trunk line side is 9. Also, telephones 51 to 56 are each 51 to 56
56 is the subscriber number.

If you want to make a plainphone call from the telephone 55 of the electronic exchange 22 to the telephone 51 of the electronic exchange 20, dial 71-51 and the connection will be established. To make a confidential call, dial 8-71-9-51. When making a confidential call from telephone 52 of electronic exchange 20 to telephone 53 of electronic exchange 21, dial 8-72-9-53 in the same manner. The electronic exchanges 20 and 22 are provided with a plurality of concealment devices when they are frequently used, and are configured to allow use of an available concealment device, such as a representative number, by specifying a dial.

(g) Effects of the Invention According to the present invention, as explained in detail above, when making a secret call between telephones housed in opposing electronic exchanges, there is no need for each telephone to have a secret device, and each telephone freely carry a small number of hidden devices,
Since it can be used in common, an economical system can be constructed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electronic switching system according to an embodiment of the present invention, and FIG. 2 is a block diagram of an electronic switching circuit network according to an embodiment of the present invention. In the figure, 1 to 3, 51 to 56 are telephones, 4 is a line network, 5 is a trunk link network, 6 is a communication path control device, 7 to 9 are out-of-band dial signal in/out trunks, 10, 30 to 35 are Hidden device, 11 is ORT, 12 is TNT, 13 is RGT,
14 is OST, 15 is central control unit, 22-22
is an electronic exchange, and 41 to 44 are trunk lines.

Claims (1)

[Scope of Claims] 1. Out-of-band dial signal input/output is connected to trunk link networks of first and second electronic exchanges facing each other and each accommodates a plurality of subscriber terminals. The first and second electronic exchanges are connected via a trunk, and each of the calling and called subscriber terminals is connected to the first and second electronic exchanges by a dial signal from the calling subscriber terminal. Dial signal entry/exit trunk, digital concealment device,
A connection means for secure telephone calls connected via an out-of-band dial signal input/output trunk is provided, and a dial signal from a subscriber terminal on the calling side is connected to a digital secure telephone connection provided in each of the first and second electronic exchanges. A secret call method characterized in that a secret call can be made with a subscriber terminal on the called side using a device.