JPH03183249A - Discrete line digital data communication system - Google Patents

Abstract

PURPOSE:To avoid such operation that a call originating side holds a line as waiting for a response by holding a signal trunk at a call originating station and a call incoming station, and sending a signal for call incoming refusal from the signal trunk of the call incoming station to the call originating station when the call incoming refusal occurs. CONSTITUTION:At the station A, the signal of the data terminal idle of a callee side from the station B is received by the signal trunk 3. A central control device 5 does not disconnect the channels of a digital trunk 4 and the signal trunk 3, and when the call incoming refusal is raised from a data terminal 13 at the station B, the central control device 14 issues a call incoming signal sending instruction to the signal trunk 11. At the station A, when the call incoming refusal signal from the station B is received by the digital trunk 4, the central control device 5 disconnects the channels of the signal trunk 3 and the digital trunk 4, and restores the digital trunk 4, and shows the message of the data terminal call incoming refusal of the callee side to the data terminal 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an individual line digital data communication system, and more particularly to an individual line digital data communication system that notifies the opposing station of call rejection information of a receiving terminal before the start of data communication.

[Conventional technology]

In the conventional individual line digital data communication system, the originating station sends a selection signal to the opposite station, establishes a communication path between the originating trunk and the signal trunk, prepares to receive the signal from the opposite station, and after receiving or The communication path between the outgoing trunk and the signal trunk is disconnected by timer processing after no reception is received.

Furthermore, at the receiving station, when a call is received, a communication path between the receiving trunk and the signal trunk is established, and after transmitting the receiving terminal status as a signal to the originating station, the communication path between the receiving trunk and the signal trunk is disconnected.

[Problem to be solved by the invention]

In the conventional individual line digital data communication system described above, after the originating station receives a signal such as the terminating terminal is empty from the opposite station, the communication path between the originating trunk and the signal trunk is disconnected, so the incoming call is subsequently rejected. Even if a signal is sent by the receiving station, it cannot be received by the transmitting station. Also. The receiving station checks the status of the called terminal, sends a signal from the signal trunk to the calling station via the receiving trunk, and then disconnects the communication path between the receiving trunk and the signal trunk, so the receiving terminal then rejects the call. Even if this happens, a signal rejecting the call cannot be sent to the originating station, and one originating terminal ends up holding the line while waiting for a response from the terminating station.

[Means to solve the problem]

The individual line digital data communication system of the present invention includes a trunk for digital communication, a signal trunk for transmitting and receiving signals during individual line digital data communication, and a program address necessary for analyzing the received signal and storing it in the signal memory for processing. is written in the control device, and even after the communication path between the digital trunk and the transmitting data terminal is set, the communication path between the signal trunk and the digital trunk is maintained and signal monitoring is performed to communicate with the opposite station. This is a configuration that allows reception of incoming call rejection signals from.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Referring to FIG. 1 showing one embodiment, the data terminal 1 at the A station makes a call to the data terminal 13 at the B station via individual line inter-office digital data communication, and after sending out a selection signal from the digital trunk 4, the data terminal 1 from the B station Waiting for a signal. Station B receives the selection signal from station A and checks the status of the data terminal 13 on the called side. When the data terminal 13 in the B station sets call rejection, the information is not sent to the central control unit 14 before the call arrives, so the call is not recognized as an empty state and the call is sent, and at the same time, the data terminal 13
A signal exit instruction is issued, and the communication path between the digital trunk 10 and the signal trunk 11 is kept connected.

At the A station, the signal from the called data terminal from the B station is received by the signal trunk 3 via the digital line 9 and the digital trunk 4, and sent to the central control unit 5. The central control unit 5 scans the signal memory 6, reads out the address of the processing program corresponding to the called data terminal empty signal from the processing address section 8, and executes it. The call path between the digital trunk 4 and the signal trunk 3 is not disconnected, and the data terminal 13 rejects the call at the 9B station, which instructs the signal trunk 3 to process the signal reception from the B station and monitor the response process to the digital trunk 4. In this case, the central controller 14 issues an instruction to the signal trunk 11 to send a call rejection signal. The signal trunk 11 sends an incoming call rejection signal via the digital trunk 10 and the digital line 9, and waits for a signal reception completion signal from the A station. At station A, the incoming call rejection signal from station B is sent via digital line 9 to digital trunk 4.
and sends it to the central control unit 5. The central control unit 5 scans the signal memory 6, reads out the address of the processing program corresponding to the incoming call rejection signal from the processing address section 8, and executes it. This program sends a reception completion signal from signal trunk 3 to station B, disconnects the communication path between signal trunk 3 and digital trunk 4, opens the communication path between data terminal 1 and digital trunk 4, and 4 and displays a message to data terminal 1 rejecting the call from the data terminal on the called side. When the B station receives the reception completion signal from the A station on the signal trunk 11, the central control unit 14 disconnects the communication path between the digital trunk 10 and the signal trunk 11, and puts the station in a restored state. Furthermore, the communication path between the digital trunk 10 and the data terminal 13 is opened, the digital line 9 is emptied, and the series of controls is completed.

〔Effect of the invention〕

As explained above, according to the present invention, even after the terminating station sends a signal, the signal trunk is maintained at the originating station and the terminating station, and when a call is rejected, the signal trunk of the terminating station is transmitted to the originating station. On the other hand, by sending a call rejection signal, the data terminal on the calling side is notified of the occurrence of call rejection, which prevents the caller from being able to see the status of the called party and putting the line on hold while waiting for a response.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Data terminal, 2... Switch, 3... Signal trunk, 4... Digital trunk, 5... Central control unit, 6... Signal memory, 7... Signal section, 8 ...Processing address section, 9...Digital line, 10...Digital trunk, 11...Signal trunk, 12...Switch, 13...Data terminal,
14... Central control device, 15... Signal section, 16
...Processing address section, 17...Signal memory.

Claims (1)

[Claims] A trunk for digital communication, a signal trunk for sending and receiving signals during individual line digital data communication,
A control device that analyzes the received signal and has a program address necessary for processing written in the signal memory, and even after the communication path between the digital trunk and the transmitting data terminal is established, the signal trunk and the An individual line digital data communication system characterized by maintaining a communication path with a digital trunk, monitoring signals, and making it possible to receive a call rejection signal from the opposite station.