JPH07221755A - Communication interface circuit - Google Patents

Abstract

PURPOSE:To attain the connection to an emergent communication object termi nal equipment even when a communication channel of a called party is busy by setting an emergency communication compatible program. CONSTITUTION:When a communication channel use state recognition means 13 confirms it that a bus 23 of an ISN network interface circuit has an emergency communication request call of D-channel and no idle channel is available, a TEI value of a busy terminal equipment is stored in a busy terminal equipment storage means 14. A communication channel forced interrupt means 15 sends a communication channel open request to the communication network. Upon the receipt of the request, the communication network interrupts all communication channels. When a channel interruption state recognition means 16 recognizes interrupt of the communication channel, an emergency communication sender side sends emergent communication again and the communication network makes connection with a prescribed terminal equipment. Thus, the communication channel at receiver side is immediately connected to a prescribed terminal equipment independently of the operating state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to INS Net 64 of Japan (NTT ISDN service integrated digital communication network).
Between terminals on the line connected to the communication system, when an emergency communication arrives when there is no vacant channel on the called side, the called side is forced to disconnect all communication channels,
The present invention relates to an interface circuit for the ISN net 64, which has a function of allowing the calling side to recognize the disconnection of the called side and make a call again.

[0002]

2. Description of the Related Art As shown in the overall configuration diagram of a communication network of FIG. 2, in the INS Net 64 communication system, a maximum of eight communication terminal devices are connected to one service line via a DSU (digital circuit terminating device). Can be connected. If there is an incoming call from the communication network when there is no available connection on the communication channel that shares the above line, it is possible to make a simultaneous announcement of "incoming call" to notify all the connected terminals of the incoming call. ing. However, when an emergency communication request is made at a remote terminal and an incoming call arrives, there is a problem that appropriate measures cannot be immediately taken, especially when a computer system for measurement control is connected to both terminals.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention that, even if a communication channel on the called side is in use, the calling side is temporarily disconnected by receiving a request for emergency communication to disconnect the channel in use. The purpose is to realize an interface circuit for ISN net 64 having a function of recognizing disconnection of and recognizing the disconnection.

[0004]

The above operation is realized by using a microprocessor. ISDN controller is NTT
It is configured to be compatible with the ISDN service of. The interface circuit of the present invention, which is connected to a communication network capable of requesting the release of the connection from either the originating terminal or the terminating terminal, has an emergency communication recognizing means, a communication channel use status recognizing means, and a communicating terminal storing means. And the communication channel forced disconnection means and the receiving side channel disconnection state recognition means. Even if the communication channel on the receiving side is in use, the channel in use is temporarily disconnected and the calling side disconnects the receiving side. Recognizes that the emergency communication is transmitted again and the terminal can be connected to a predetermined terminal.

[0005]

The urgent communication recognition means identifies whether or not the incoming call from the communication network is a request for urgent communication. The communication channel usage status recognizing means, in response to the emergency communication recognizing means recognizing that there is an emergency communication request, determines whether or not all other terminals connected to the same communication line are in communication. Identify.

The communication terminal storage means stores the identification code of the terminal in response to the fact that the communication channel usage status recognition means recognizes the terminal using the communication channel. While there is this memory, it indicates that communication is in progress. The communication channel forced disconnecting means transmits a signal requesting the release of the communication channel to the communication network when the arrival of the emergency communication request is confirmed while the communication channel is full. The communication network receives this signal and disconnects all communication channels.

The receiving side channel disconnection state recognizing means transmits a signal requesting disconnection of all communication channels being communicated by the receiving side communication channel forced disconnecting means, and the communication network receives this signal and receives all the communication channels. This is an operation on the interface circuit of the emergency communication requesting side, which recognizes that the communication has been disconnected. With this configuration, even if the communication channel on the called side is in use, the channel being used is temporarily cut off, the calling side recognizes the disconnection on the called side, and the emergency communication is sent again. Can be connected to a predetermined terminal.

[0008]

The present invention will be described below with reference to the drawings. FIG. 1 is a block wiring diagram showing an embodiment of the present invention. 11
Is an ISDN controller. It is connected to the DSU and controls communication according to the ISDN protocol of NTT.

Reference numeral 12 is an emergency communication recognition means. Identify whether the incoming call from the network is an emergency communication request. Reference numeral 13 is a communication channel usage status recognition means. When the emergency communication recognizing means 13 recognizes the incoming call of the emergency communication, it identifies whether or not there is a free communication channel. Reference numeral 14 is a communication terminal storage means. The terminal using the communication channel is recognized and the TEI is stored for use in the forced disconnection procedure.

Reference numeral 15 is a communication channel forced disconnection means.
When the arrival of an emergency communication request is confirmed in the state where there are no free channels, the communication network is called to open the communication channel. Reference numeral 16 is a receiving side channel disconnection state recognition means. When the terminal issues an emergency communication request, it recognizes that the communication channel on the called side has been forcibly disconnected. Reference numeral 17 is a channel bus control unit. Connects to the computer's channel bus and controls the channel bus protocol.

Reference numeral 18 is a channel bus for connecting the channel bus control unit and terminal equipment such as a computer. Reference numeral 19 denotes a communication data bus, an address bus of the interface circuit,
It is an internal bus including a control bus. FIG. 2 is an overall configuration diagram of a communication network according to the present invention.

Reference numeral 20 denotes an ISN net 64 communication network (hereinafter referred to as a communication network), to which a DSU of a subscriber to the communication network is connected. Reference numerals 21a and 21b denote DSUs (Digital Line Terminators), which are equipments connected to the end of the communication network and include speed conversion, a test loop function, an overvoltage protection function, and the like for matching the communication network and the terminal.

22a and 22b are ISN nets 6 of the present invention.
4 shows a block of the interface circuit of FIG. 23a,
23b is a DSU and communication interface circuits 22a, 22
It is an internal wiring bus for connecting the terminals b and the terminals 2a to 8a and 2b to 8b, and is usually composed of two channels of B channel and one channel of D channel.

Next, the interface circuit 22a of the present invention,
The operation of 22b will be described with reference to the flowchart.
FIG. 3 is a flowchart showing the operation of the interface circuit. The part surrounded by the dotted line is the feature of the present invention. The numbers with an S in the upper right of each element of the chart are for explaining the steps.

The interface circuit of the ISN net 64 constantly monitors the data on the home wiring buses 23a and 23b (S1). When there is an incoming call, whether the incoming call is a self-addressed notification or a simultaneous notification (S2), D channel (Dch)
Whether it was received at (S3) or there was an emergency communication request (S)
4) It is checked whether an incoming call has been received by the incoming call notification (S5). If any of the above applies, the communication channel disconnection process (S6) is immediately performed.

Here, the fact that the signal is received by Dch means that it is a call control protocol (Q931 / Q921) or an ID check procedure. It also means that Bch was connected by the Dch call control and received by the data communication protocol. (S10) Whether or not it is an emergency communication request is configured by adding a signal indicating that it is an emergency communication to the User-User information portion of the call control message. This signal transparently passes through the communication network and reaches the called party.

When it is confirmed by the above-mentioned checks that an emergency communication has arrived without a vacant channel, communication channel disconnection processing is executed. FIG. 4 is a flowchart showing the recognition processing operation of the communicating terminal. The communication channel use status recognizing means 13 monitors the call control message appearing on the D channel to determine which terminal is communicating.
Alternatively, when the CONN ACK message is confirmed, it is determined that the communication channel is connected, and the TEI value included in the Q921 message is recorded in the communicating terminal storage unit 14. In the case of a REL or REL COM message, it is determined that the communication channel has been disconnected and the corresponding TEI recorded is deleted. (S7 of FIG. 3) FIG. 5 is a flowchart showing the communication channel disconnection processing operation.

In the communication channel disconnection processing operation, if the communication channel is being used by itself, the channel is disconnected,
Prepare for a new incoming call. When the communication channel is in communication with another terminal and the incoming call from the communication network is a request for emergency communication, the interface circuit of the present invention uses the TEI of the terminal in communication to perform network communication. A "TEI verification" request is sent to. Then, an "ID check request" is transmitted from the network, and upon receiving this, the terminal in the communication state returns an "ID check response". Due to this series of operations, a TEI double allocation state occurs between the network and the terminal, and the network temporarily disconnects this communication channel. (S6 in FIG. 3) The TEI targeted in the communication channel disconnection process is read from the communication terminal storage means 14.

Therefore, the sender of the emergency communication is promptly connected to a predetermined terminal by confirming that the channel of the receiver is free and making a call again. By providing this communication interface circuit on each of the transmitting side and the receiving side, emergency communication can be transmitted from either side. Here, TEI is a "terminal identifier" and constitutes a part of the call control signal in the communication channel. It is a code assigned to identify a plurality of terminals connected to one interface.

"TEI verification" is a procedure for requesting the network to activate the TEI check procedure when the terminal detects an abnormality in TEI. "TEI check" means that the network
This is a procedure for inquiring whether a certain TEI is in use or checking the TEI in use. "ID check request"
To receive the "ID check response". The ID means an identification number. All of these procedures are Q931 /
It is processed according to the Q921 protocol. (S8,
S9) The TEI used in the communication channel disconnection process is retrieved from the communicating terminal storage unit 14.

The part * 1 in FIG. 3 is a part showing a process when an emergency communication request is transmitted and the request is rejected by the receiving side. That is, when the call control message of the Q931 / Q921 protocol fails the emergency communication request sent to the communication network, the reason display notified from the communication network is referred to, and when "link layer abnormality" is confirmed,
The receiving side determines that the communication channel has been disconnected, and sends the emergency communication request again.

By this operation, the emergency communication request is immediately accepted when the disconnection of the channel on the called side is completed. Here, Q931 is a network protocol (layer) for performing call control such as line allocation / connection / disconnection control in ISDN. Q921 is I
It is a link layer protocol (layer) on the D channel for performing call control such as line error detection / retransmission control in SDN.

FIG. 6 is a diagram showing a signal flow at the time of double allocation of TEI. The operation is as described in FIG.

[0024]

According to the present invention, when an urgent communication request is made in a state where the communication channel on the called side is full, the interface circuit of the present invention sends a disconnection request to the network. The signal can be detected and disconnection processing can be performed, and then the channel in communication is forcibly disconnected, so when the emergency communication request is reissued, the communication channel on the receiving side is immediately irrespective of the usage status. Has the effect of being connected to a predetermined terminal.

[Brief description of drawings]

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

FIG. 2 is an overall configuration diagram of a communication network according to the present invention.

FIG. 3 is a flowchart showing the operation of the interface circuit.

FIG. 4 is a flowchart showing a communication channel disconnection processing operation.

FIG. 5 is a flowchart showing a recognition processing operation of a communicating terminal.

FIG. 6 is a diagram showing a signal flow in the case of dual allocation of TEI.

[Explanation of symbols]

 11 ISDN control unit 12 emergency communication recognition unit 13 communication channel use status recognition unit 14 communication terminal storage unit 15 communication channel forced disconnection unit 16 callee side channel disconnected state recognition unit 17 channel bus control unit 18 channel bus 19 internal bus 20 ISN net 64 communication network 21a, 21b DSU (digital circuit terminating device) 22a, 22b communication interface circuit 23a, 23b private wiring bus

Claims (1)

[Claims] 1. A communication interface circuit connected to a communication network capable of requesting release of connection from either a calling terminal or a receiving terminal, and identifies whether an incoming call from the communication network is a request for emergency communication. Responsive to the emergency communication recognizing means that recognizes that it is a request for emergency communication, and identifies whether or not all other terminals connected to the same communication line are in communication. A communication channel use status recognizing means, and a communication terminal storage means for recording the identification code of the terminal in response to the communication channel use status recognizing means recognizing the terminal using the communication channel, When the arrival of an emergency communication request is confirmed when there is no available communication channel, communication channel forced disconnection means that sends a signal requesting the release of all communication channels to the communication network. Since the communication channel forced disconnection means on the receiving side has issued a signal requesting the release of all communication channels in communication stored in the communication terminal storage means, all communication channels in communication are in communication network. If disconnected from
A communication interface circuit comprising: a terminating side channel disconnection state recognizing means for recognizing that a forced disconnection has occurred in a communication channel on the receiving side on the side requesting emergency communication.