JPS6239578B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling communication between terminals in a circuit switching system.

In conventional circuit switching systems, the setup of a call requested by a terminal is completed using a known procedure, and after the path between terminals is established, the switching system does not receive any signals other than a recovery request from the terminal. Therefore, during communication between terminals, the communication state is changed to terminal-switching equipment, and various information is exchanged.
There was a drawback that it was not possible to return to the terminal-to-terminal communication state after that.

In order to eliminate such drawbacks, the present invention controls communication between terminals in line switching using a specific pattern of S bits, thereby making it possible to exchange information between terminals and exchanges without releasing the call. An embodiment of the present invention will now be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing a communication control system according to an embodiment of the present invention. The enveloped D bit and S bit signals on the subscriber line enter the signal input terminal 1 and are sent to the S bit extractor 2.
sent to. Here, the envelope signal is sent as is to the reception signal switching section 3, and at the same time only the S bits in the envelope are sent to the S bit specific pattern detection section 4. The S bit specific pattern detection unit 4 collects S bits of a specific length and constantly monitors a specific pattern A transmitted from a terminal during communication between terminals. When the S bit specific pattern detection unit 4 detects the specific pattern A, it sends a signal to notify the specific pattern A to the reception signal switching unit 3, transmission signal switching unit 5,
The S bits are simultaneously sent to the specific pattern generating section 6. 3 receives a signal indicating that the specific pattern A has been detected from the S-bit specific pattern detection section 4, and transfers the envelope that has been received from the S-bit extraction section 2 and sent to the output terminal 7 to the communication path section of the exchange to the communication path. The signal is sent to the signal receiving section 8 without being sent to the output terminal 7 to the section. In addition, in the transmission signal switching section 5, until now, the input terminal 9 from the communication path is connected to the receiving S bit insertion section 1.
0, the signal transmitting section 11
The signal from the S bit inserter 10 is sent to the S bit inserter 10. S
When the bit specific pattern generating section 6 receives a signal indicating that the specific pattern A has been detected from the S bit specific pattern detecting section 4 or receives a signal appearing at the instruction terminal 12 from the signal processing section of the exchange, it generates a specific pattern A of a certain length. Alternatively, a different specific pattern B is created and sent to the S bit insertion section 10. The S bit insertion unit 10 inserts a signal of a specific pattern A or a specific pattern B once or multiple times.
It is inserted into the S bit of the envelope signal sent from the transmission signal switching unit 5 and sent to the output terminal 13 to the subscriber line. Separately from this, a signal indicating that the S-bit specific pattern detection section 4 has detected the specific pattern A is transmitted through the terminal 14 to the signal processing section, and is notified to the other party's terminal by sending an interoffice signal from there. In this way, the signal from the terminal is sent to the signal processing unit via 1, 2, 3, 8, 15, and the signal from the signal processing unit is sent to 16,
11, 5, 10, and 13 to the terminal, and a communication state between the terminal and the exchange is established. Furthermore, in order to establish a terminal-to-terminal communication state again, the terminal sends out a specific pattern C using the S bit. Then, the S-bit specific pattern detecting section 4 detects it and simultaneously sends a signal to the receiving signal switching section 3, the transmitting signal switching section 5, and the S-bit specific pattern generating section 6. When receiving the signal, the received signal switching section 3 sends the envelope signal, which has been received from the S bit extraction section 2 and sent to the signal receiving section 8, to the output terminal 7 to the communication path section, and then sends it to the signal receiving section 8. Stop sending. The transmission signal switching section 5 cuts off the signal from the signal transmission section 11 that has been received so far, and sends the signal from the input terminal 9 from the communication path section to the S bit insertion section 10. Further, the S bit specific pattern generation section 6 has 4 bits.
When a notification that a specific pattern C has been detected is received from the signal processing section or a signal appearing at the instruction terminal 12 from the signal processing section is received, the specific pattern C or a specific pattern D different from this is sent to the S bit insertion section 10. The pattern is inserted into the S bit repeatedly one or more times and sent to the terminal from the output terminal 13 to the subscriber line. Also, apart from this, S
When the bit specific pattern detection section 4 detects the specific pattern C, the signal is transmitted to the signal processing section through the terminal 14, and from there is transmitted to the other party's terminal by an interoffice signal. In this way, the terminal-to-terminal communication state is established again.

Because of this operation, during communication between terminals, by using the S bit from the terminal and sending a specific pattern A to the exchange, the communication path set in the communication path section of the exchange is held and the communication between terminals is completed. By physically cutting off the communication path, information can be exchanged between terminals and exchanges. Furthermore, by sending the specific pattern C after the terminal-exchange communication state is established in this manner, it is possible to return to the terminal-terminal communication state again. By the above-described procedure, it is possible to realize various forms of communication that could not be realized conventionally in the circuit switching system. Examples of these are described below.

In FIG. 2, the terminals 17 and 18 are initially communicating, and in this state, when the terminal 17 transmits 20, which is a specific pattern A of S bits, to the switching center 19, the switching center 19 transmits a specific pattern A of S bits or a specific pattern A of S bits. Return pattern B, 21, to terminal 17,
The terminal 17 is permitted to send a signal to the switching center 19, and at the same time, an inter-office signal 22 is sent to notify the other terminal of the interrupt state. The exchange 23 accommodating the terminal 18 receives this inter-office signal, sends the S-bit specific pattern A or 24, which is the specific pattern B, to the terminal 18, and receives the specific pattern A, 25, from the terminal 18. The communication state between the switching center 23 and the terminal 18 is established by this. In this state, signals 26, 27, 28, 29, 30, and 31 for holding the communication path are exchanged between the terminal 17 and the terminal 18. Thereafter, the terminal 17 sends a calling signal 33 for the third terminal 32 to the exchange 19, which is converted into a call signal 34 between the stations and sent to the exchange 35. The exchange 35 transmits it to the third terminal 32 as an incoming call signal 36. Then the third terminal 3
The response from 2 becomes 37, 38, 39, and terminal 1
7 and a communication path between the terminal 17 and the third terminal 32 is established. To set the terminal-to-terminal communication state, the terminal 17 sends a specific pattern C 4.
0, the exchange 19 returns 41, which is the specific pattern C or D, and transmits it to the other party's exchange 35 through 42, and sends 43, where 35 is the specific pattern C or D, to the terminal 32. returns 44, which is the specific pattern C. In this way, a communication state 45 is established between the terminal 17 and the terminal 32. When the communication between the terminal 17 and the terminal 32 is completed, the communication state between the terminal and the exchange is established by exchanging the same specific pattern as above up to 46, 47, 48, 49, 50, 51, 52, 53, 54,
The communication path with the terminal 32 is released by the disconnection sequences 55 and 56. Then 57, 58, 59,
Terminal 1 by the sequence up to 60, 61, 62
The hold status of the communication path between 7 and 18 is released and 6
By exchanging specific patterns of S bits up to 3, 64, 65, 66, and 67, terminal 17 and terminal 18
A terminal-to-terminal communication state is established between the two terminals. In the above explanation, the communication path between the terminal 17 and the terminal 18 can be released when the sequences up to 25 are completed. Further, it is also easy to release the communication path with the terminal 18 first after the sequence up to 50 is completed. Furthermore, it is also possible to perform three-way communication among terminal 17, terminal 18, and terminal 32. Furthermore, if the switching center 19 has a bucket switching function, the circuit switching communication path between the terminals 17 and 18 can be held and a call can be made to a packet terminal accommodated in the packet switching center. is also possible.

As explained above, the present invention has the advantage that various communication forms are possible. Furthermore, in this system, the switching center only needs to look at a specific pattern of the S bit during communication between terminals, and there is no need to look at the contents of the D bit. Information can be shared and transparency can be ensured.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows an example of a communication form made possible by the present invention. DESCRIPTION OF SYMBOLS 1...Input terminal from the subscriber line, 2...S bit extraction section, 3...Reception signal switching section, 4...S bit specific pattern detection section, 5...Transmission signal switching section,
6... S bit specific pattern generation section, 7... Output terminal to the communication path section, 8... Signal receiving section, 9... Input terminal from the communication path section, 10... S bit insertion section, 11... Signal transmission unit, 12...Indication terminal from the signal processing unit, 13...Output terminal to subscriber line,
14... Report terminal to the signal processing section, 15... Output terminal to the signal processing section, 16... Input terminal from the signal processing section, 17, 18, 32... Terminal, 19, 2
3, 35... exchange, 20-22, 24, 25,
40-44, 46-50, 63-67... S bit specific pattern sequence, 26-31... Pass hold sequence, 33, 34, 36-39... Calling sequence, 45... Communicating, 51-56 ……
Disconnection, 57-62...Pass hold release sequence.

Claims (1)

[Claims] 1. A transmission path on which a plurality of information bits (D bits) and at least one status bit (S bit) for transmitting call control signals and information such as call origination and disconnection are time-division multiplexed, and the transmission path The contents of the D and S bits sent from the transmission path are exchanged between terminals that have the function of sending call control signals and information such as call origination and disconnection using the D bit, and various status signals using the S bit. In a system consisting of an exchange having the function of
When the exchange detects a specific pattern sent by the terminal to the S bit based on its own request or a request for a specific pattern sent by the exchange, the exchange releases the call between the terminal and the other terminal. The communication path between the terminal and the other terminal is switched to the communication path between the terminal and the exchange, and the exchange sends back a specific pattern to the S bit to the terminal and communicates between the terminal and the exchange. At the same time, the other terminal is notified of the interrupt status by an inter-office signal, and the terminal or exchange sends a specific pattern using the S bit, and the terminal-to-terminal communication is resumed via the communication path between the terminal and the exchange. A communication control method characterized by returning to the communication path.