JPS61278262A - System for connecting outgoing relay line in telephone exchange system - Google Patents

Abstract

PURPOSE:To improve the utilizing efficiency of a relay line by sending a busy tone to an incoming line connected to an outgoing line from the inside of an exchange station to restore immediately the outgoing trunk connected to the outgoing relay line when an outgoing exchange detects a busy tone returned from the outgoing relay line. CONSTITUTION:When a called telephone set TELB4 is busy, an incoming exchange EXB3 connects an incoming trunk ICT32 and a busy tone sender BT33 to return a busy tone. The busy tone reaches a calling telephone set TELA2 via a relay line, an outgoing trunk OGT12 and a channel switch SWA11 and inputted to a busy tone detector BTD14 at the same time. When the BTD14 detects a busy tone, the detected output allows a CPU15 to switch the channel connecting a TELA2 and the OGT12 to the connection of the TELA2 and the BT13. Then the TELA2 receives a busy tone of the outgoing exchange EXA1, the OGT12 reaches the same state as the cutoff of the TELA2, a cutoff signal is sent to the EXB33 for cutoff. When a cutoff end signal is returned from the EXB3 to the OGT12, the OGT is restored and the relay line is used for the next talking.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an outgoing trunk line connection method, particularly an outgoing trunk line in a telephone switching system that transmits busy tone from a subsequent station to a calling party via a telephone line. Regarding the connection method.

(Prior Art) In a public telephone network, etc., when a calling subscriber makes a call to a party other than his or her own station, a call is made from the exchange where the subscriber is accommodated to the subscriber exchange where the other subscriber is accommodated.
It is received via trunk lines and transit exchanges. At this time, the originating switching center generally selects an outgoing trunk connected to the required trunk line, and sends and receives control signals and supervisory signals to and from the downstream station via this outgoing trunk, but from the downstream station to the other party. When a busy tone indicating that a subscriber, etc. is busy is sent, this busy tone repeatedly passes through the outgoing trunk and reaches the second calling subscriber. Therefore, the calling subscriber listens to this busy tone and performs an on-footer, that is, disconnects the call.

[Problems to be Solved by the Invention] However, in the conventional outgoing trunk line connection system described above, the caller who hears the busy tone does not necessarily go on-hook immediately, and may receive the busy tone unnecessarily. There are times when I am. This busy tone is sent from the switching point where the subsequent station is busy. For example, if the called party is busy, the busy tone is sent from the switching station that accommodates the called party, and Because trunk lines are put on hold, the problem is that the efficiency of actual use of trunk lines does not improve by that much, whether the called party is overseas via an international trunk line or even within Japan. be.

SUMMARY OF THE INVENTION An object of the present invention is to provide an outgoing trunk line connection system that enables efficient trunk line operation by detecting a busy tone at the originating station of a trunk exchange and restoring the outgoing trunk.

(Means for Solving the Problems) The present invention provides means for detecting a busy tone sent back from an outgoing trunk line in an originating exchange, and when the busy tone from the outgoing trunk line is detected, the outgoing trunk Causes the incoming line connected to the line to transmit a busy tone from within this exchange, and immediately restores the outgoing trunk to which the outgoing trunk line is connected, so that this outgoing trunk line can be used for other connections. It is something.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which an originating exchange (EXA)1 transmits information from a called telephone (C) to a device (B) via a trunk line based on dials from a calling telephone (C) to a device (A)2. )
4 is connected to an terminating exchange (hereinafter referred to as EXE) 3 accommodating 4. In the figure, EXA 1 is the same as a normal subscriber exchange, and is connected to the communication path switch C and below (SWA).
l'l''K Place A2, outgoing trunk (hereinafter referred to as 0GT) 12.
In addition to accommodating a busy tone transmitter C (hereinafter referred to as BT) 13 and the like, a busy tone detector (hereinafter referred to as BTD) 14 is also accommodated, and these call abbreviations a are exchange controlled by a switching processing unit (hereinafter referred to as CPU) 15. It is configured to accept. On the other hand, EXB3
H A call route switch (hereinafter referred to as 5WB) at a normal subscriber exchange
) 31, ICT) 32 below the incoming trunk C, BT 33, etc. are accommodated.

FIG. 3 is a time chart when the station A2 dials the busy station B4 in FIG. 1. The operation in FIG. 1 will be explained below with reference to FIG. First, when station A2 makes an off-hook call, EXAI detects the call and
The dial tone is sent back to station A2, and after listening to this dial tone t-, station A2 sends a dial for connection to station B4. Next, EXAI becomes 0 when the reception of the dial is completed.
ICT3 of EXB 3 via GT12 and trunk line
Start 2. When EXB 3 returns a start-up completion signal according to the normal method, EXAI sends a selection signal to work 3, and at the same time as the sending is completed, a communication path is created between 0GT12 and station A2, but EXAI communicates with this 0GT12 and BTD14. Also make roads. On the other hand, upon receiving the selection signal, EXB 3 immediately starts a connection operation to station B4, but since TBLB4 is busy, it connects IC'l' 32 and BT 33 and returns a busy tone. This busy sound is a relay line, UGT12,5
Arrives at location A2 via WAII, but at the same time BTD14
is input. When the BT-D 14 detects the busy tone, it sends a detection output to the CPU 15. Next CPU1
5 switches to the communication path i which was connecting A2 and (JG'r12) to the connection between A2 and BT13.Therefore, the busy tone of EXAI is sent to A2, and 0GT12 is the same as disconnecting A2. A disconnection signal is sent to EXB3 to disconnect it. Next, when a disconnection completion signal is sent back from EXB3 to 0GT12 (JGT12 is restored and the trunk line can be used for the next call. BT
When 13 is connected to station A2, the connection is broken and released, so do not wait for EXAI i'f'ELA2 to on-hook (, the busy tone from EXB3 becomes BTD1
4, JGT12 immediately starts the trunk line restoration operation, which eliminates unnecessary suspension of the trunk line.

FIG. 2 is a block diagram of another embodiment of the present invention, in which an originating exchange (hereinafter referred to as EXA) 6 has a function of transmitting a busy tone from a line circuit (hereinafter referred to as LC) 63 in the same relay exchange as in FIG. The figure also shows a case where the outgoing trunk (hereinafter referred to as α■) 62 is equipped with a busy tone detector. In FIG. 2, the same reference numerals as in FIG. 1 indicate the same functions.

The LC63 can connect the telephone line and the BT13 by a contact bt controlled by a central processing unit (hereinafter referred to as CPU) 64, and the 0GT62 has a response monitoring relay E connected between the telephone lines via a diode Di. The BTD 14, which has been disconnected between call lines, is disconnected from the call line after the called party answers.

In the above configuration, when station A2 dials busy station B4, the operation is performed according to the time chart in Figure 3, which is exactly the same as in Figure 1, but after sending the selection signal from EXA6. BTD via call path switch 11
14 'D14 detects the busy tone and sends the detection to the CPU 64.
64 operates the contact bt of LC63 to send the busy sound to station A2, and completely disconnects station A2 and 0GT62. In addition, in the explanation of FIG. 1 and FIG. 2, EXAl and EXB3 &Rabi[CEXA6,! : EXH3,!
:t [It is assumed that these exchanges are connected by a liquid trunk line, but even if there are multiple relay exchanges between these exchanges, the transmission of the busy tone is exactly the same, and the recovery of the station downstream of the originating exchange is also It's done exactly the same way.

(Effects of the Invention) As described in detail above, according to the present invention, when a busy tone is sent to the calling party while the called party is busy or the trunk line is all busy, the trunk line is immediately released. The efficiency of using trunk lines can be increased.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a block diagram showing another embodiment of the present invention, and Fig. 3 is a diagram explaining all the connection operations in Figs. 1 and 2. 0 1.6... Outgoing exchange (EXA), 2.4...
...Telephone (place A, place B), 3... Incoming exchange (EXB input 11.31...-Call path switch (
SWA, 5WB), 12...outgoing trunk (OG
T), 13, 33... Busy tone transmitter (BT),
14... Busy tone detector (BTD). /-2) $fWJ Kaya 21! r Kyo 3 bacteria

Claims (1)

[Claims] A busy sound detection means for detecting a busy sound returned from the outgoing trunk line, and a recovery means for restoring the outgoing trunk connected to the outgoing trunk line when a detection output is obtained from the busy sound detection means. and busy tone transmitting means for transmitting the busy tone of the local exchange to an outgoing line connected to the outgoing trunk line when a detection output is obtained from the busy tone detecting means. Outgoing trunk line connection method in the system.