JPH0216857A - Variable junction line absence transfer control system - Google Patents

Abstract

PURPOSE:To prevent the deterioration of call loss for an absence transfer station, and to effectively use a line and a junction line trunk by opening the junction line trunk and the line having been connected to the absence transfer station after transfer. CONSTITUTION:At the time of call incoming from an exchange office A, the control part 15 of the exchange office B discriminates the presence of registration by a transfer registration discrimination means 151, and if it is registrated, it generates a transfer control signal attached with transfer destination information DNc by a transfer control signal generating means 152, and sends it to the exchange office A by a signal transmitting receiving means 14. After the control part 15 of the exchange office A of a transmission side breaks connection to the exchange office B according to the reception of the transfer control signal, it connects the extension terminal (a) of the exchange office A and the extension terminal (c) of the exchange office C. Thus, the deterioration of the call loss for the absence transfer station can be prevented, and the line and the junction line trunk can be effectively used.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a trunk line variable missed call forwarding control system that provides a service for transferring incoming calls while a user of an extension terminal of an exchange is away to a registered extension of another exchange. Lines and trunk lines I/
The purpose of the present invention is to provide a trunk line variable absent transfer control system that can effectively utilize ranks without wasting them, and in which an extension terminal of a first switching center transfers an extension of a second switching center to a forwarding destination. When specifying and registering trunk line variable absent transfer, a relay that transfers a call from another exchange to the registered transfer destination of the second exchange when the registered extension/\ of the first exchange is received. In the line absent transfer control system, when a call arrives from another exchange, the control unit of the switching center uses a transfer registration determining means to determine whether or not the registration is registered, and if the call is registered, the transfer control signal generator adds forwarding destination information. A transfer control signal is created and sent to the other exchange on the originating side by the signal transmitting/receiving means, and the control section of the other exchange on the originating side establishes the connection with the first exchange by receiving the transfer control signal. After the transmission is disconnected, the transmitting terminal is configured to connect the originating terminal to the transfer destination terminal of the transfer destination second switching center.

[Industrial Field of Application] The present invention relates to a trunk line variable missed transfer control system that provides a service for transferring incoming calls while the user of an extension terminal of a switching center is absent to a registered extension of another switching center. A trunk line variable call forwarding service that spans multiple exchanges has become available as a switchboard service. If the service is registered by a user of an extension terminal at one exchange requesting transfer to an extension at another exchange, when an incoming call is received to the extension at the original exchange, Since the service has already been registered, the connection is extended from that exchange to the transfer destination exchange, and the service calls the transfer destination's extension.

In that case, the originating terminal's exchange is connected to the exchange where the original extension terminal (transfer source) is installed, and from there the connection is made to the transfer destination exchange via a trunk line.
This will occupy a lot of trunk lines. However, in the configuration of a switched network, trunk lines and trunks (trunk line equipment) are costly, so it is necessary to minimize the number of them installed. It is desired to prevent the increase.

[Prior Art] A very conventional relay call forwarding service control system is shown in FIG.

Figure 8 (a) and (b) show the case of a switching system in which three switching stations A, B, and C are connected to each other by trunk lines, as shown in (a) of Figure 8. , when subscriber terminal A housed in exchange staff makes a call and dials by specifying the extension number of subscriber terminal A housed in exchange B,
Captures the trunk (TRK) to exchange B and sends calling signal I
AM (Initial Address Message)
e with additional information
tion) is sent. At this time, the subscriber terminal on the extension of exchange B has registered the trunk line variable call forwarding, and the destination is assumed to be subscriber terminal C of exchange C.

At exchange B, the extension number of the connected subscriber terminal in the calling signal indicates that the subscriber terminal has been registered for trunk line variable call forwarding, and that the forwarding destination is subscriber terminal C of exchange C. identify. Based on the result, exchange B instructs exchange C to establish a call line via the trunk, and sends out a calling signal IAM as shown in FIG. 8(b). Exchange C calls subscriber terminal C to which it is connected, and at the same time sends an acknowledgment signal ACM (Addr) to exchange A via exchange B.
ess Complete Message). When subscriber terminal C responds (off-hook), subscriber terminal a and subscriber terminal C are able to talk.

Next, FIGS. 8(c) and 8(d) will be explained. In this case, only two exchanges A and B are involved.

The subscriber terminals accommodated in exchange B are those that have registered trunk line variable call forwarding with subscriber terminal C accommodated in exchange A. At this time, as shown in (c), when subscriber terminal A accommodated in the exchange manager makes a call and dials the number of the subscriber terminal A, exchange B receives the contents of the trunk line variable call forwarding registration. The route shown in FIG. 8(d) is formed by connecting to the subscriber terminal C housed in the switching center A, which is the transfer destination, via a trunk line.

[Problem to be Solved by the Invention] According to the conventional system described in ``-'', in the case (b) of FIG. 8, after the connection of the trunk line variable missed forwarding service is completed,
Although not involved in telephone calls, exchange A and exchange C are connected via exchange I3, and the lines and trunks between exchange A and exchange B, exchange B and exchange C are The lines and trunks to and from are occupied. In the case (d) of FIG. 8, subscriber terminal a and subscriber terminal C of the same exchange are connected via exchange 13, and the line between exchange A and exchange B is connected. The problem is that because the ranks are occupied, an extra number of lines and trunks are used, thus increasing the call ln rate to exchange B.

SUMMARY OF THE INVENTION An object of the present invention is to provide a trunk line variable absent transfer control system that can effectively utilize lines and trunk trunks without wasting them.

[Means to solve the problem] A basic configuration diagram of the present invention is shown in FIG.

This figure shows a switching system in which three exchanges A, B, and C are interconnected by trunk lines; 10 in the figure represents exchange A, 11 represents exchange C, 112 represents exchange B, and 13 to 1 represent exchange center B.
6 is a component of the switching center 13, 13 is a switching section, 14
15 is a signal transmitting/receiving means, 15 is a control unit, 5] is a transfer registration determining means, 152 is a transfer control signal generating means, 153 is a transfer control signal detecting means, 154 is a transfer path disconnecting means, 155 is a transfer transmitting means, and 16 is a transfer control signal detecting means. Represents memory.

Note that the configuration of this exchange B is shown as a representative example, and the internal configurations of other similar exchanges A and C (which have 14 configurations) are omitted from illustration.

In the present invention, when a subscriber terminal of another switching center that is a communication partner has registered for trunk line variable call forwarding when executing the "l'l" trunk line variable call forwarding service, the transfer is performed at another switching center. A transfer control signal identifying the destination terminal is sent to the originating exchange, and the originating exchange receives the signal and temporarily disconnects from the other exchange via the trunk line, and then controls the transfer connection to the transfer destination. It is something to do.

[Operation] When a call is made from extension terminal a housed in exchange A and a dial is made to specify an extension terminal housed in exchange B, it is connected to exchange I3 via a trunk line and controlled. The section 15 starts up. The control unit 15 is the transfer registration determination means 1
At step 51, it is determined by checking the trunk line variable absentee forwarding registration data 161 in the memory 16 whether the requested extension terminal has requested trunk line variable absentee forwarding service and registered a forwarding destination. If it is registered, the transfer control signal generation means 152 is started, and the transfer control signal generation means 152 extracts the transfer destination information (dial number: D) that specifies the transfer destination station and extension terminal extracted from the memory 16.
The signal transmitting/receiving means 1 generates a transfer control signal by combining information indicating trunk line variable absent transfer (indicated by Nc) and information indicating trunk line variable absent transfer.
4 to exchange A.

The control unit of exchange A detects that the received information is a control signal for trunk line variable absent transfer by means of transfer control signal detection means 153.
(Means provided in the control unit of exchange A, hereinafter the same) detects the connection from exchange A to B via a trunk line that has been captured up to that point by transfer path disconnection means 154. At the same time, the transfer calling means 155 controls the line of the extension terminal a on the calling side to be connected to the transfer destination according to the received transfer destination information DNc.

In this case, if the transfer destination is extension terminal C of exchange C, each time the trunk line is captured and the extension terminal information is sent to exchange C, extension terminal a on the calling side and extension terminal C of exchange C are connected. be done.

If the transfer destination is extension terminal d to the switching center, a control unit in switching center A performs control to connect extension terminal a and extension terminal d.

As a result, in the trunk line variable missed transfer control, extension terminal a can talk to the transfer destination extension terminal (extension C or extension d) without going through exchange B as in the past, so that the exchange manager and the exchange The lines to and from B and the corporate line I rank are not occupied by the execution of this trunk line variable call forwarding service.

[Embodiment] A configuration diagram of an embodiment of the present invention is shown in Fig. 2, and execution sequences 1 and 2 of the trunk line variable call forwarding service are shown in Figs. 3 and 4. The processing flow diagram of each process (1) to (8) by the central control unit CC is shown in the fifth figure.
It is shown in FIG. 5(a) and FIG. 5(b).

20.24 in the figure is the switching network (indicated by NW), 2L 25 is the central control unit (indicated by CC), 2
2.26 represents memory (MM), 231.272 represents a transmitting circuit, 232, 271 represents a receiving circuit, 201, 202,
243.244 is subscriber terminal (extension terminal), 203-2
05 and 241.2/12.245 are trunks (TR
K).

Although only two exchanges A and B are shown in Figure 2,
It is connected to other exchanges C, D, etc. (not shown) via trunks (indicated by TRK) and trunk lines (Ch), and control signals between the stations (network control information other than call signals, etc.) are known common line signals. According to the system, data is transmitted and received by a transmitting circuit and a receiving circuit via a common line (LK), and the common line is provided for each exchange.

In addition, the memory 22.26 is provided with a registration table (221) and a transfer destination table (222), and each registration table has a flag indicating whether or not the trunk line variable call forwarding service is registered for each extension terminal number. The forwarding destination information is displayed as “1”, 0” and is registered for each extension terminal number whose flag is 1 in the registration table in the forwarding destination table (
DNc) is stored.

Next, the flowchart of each CC process (processing by the central control unit CC) shown in FIG. 5(a) and FIG. 5(b) will be explained as follows: I will explain using

From subscriber terminal a (20+) of extension connected to NW2O of exchange A in FIG. 2 to subscriber terminal b (20+) of extension of exchange B
43) as the destination, CC to the exchange center will be sent to the exchange.
Process (1) is executed in 21. As shown in Figures 3 and 5(a), the trunk is captured and
, a calling signal JAM (control signal such as destination number information and trunk number) is transmitted to the destination station via the common signal line.

The other party's exchange then executes CC processing (2).

As shown at the beginning of FIG. 5(a), first, it is determined whether or not the extension is being registered for trunk line variable absentee forwarding based on the registration table in the memory 26, and if it is being registered, the forwarding destination table of MM 26 J: is determined. , and extracts the forwarding destination information DNc, which is the dialing information of the forwarding destination extension (step 52). Next, the dial information DNC is set in the additional information area of the response signal ACM to exchange A, and " 1 pa is set, same 53,
54), sends the created ACM signal to the exchange agent.

If you have not registered trunk line variable call forwarding in step 51 above, connect the extension terminal using existing call processing and
The transfer call flag TRS in the additional information area of the CM signal is “
It sets 0゛ (57) and sends it to exchange A.

Returning to Figure 3, when the ACM signal is received at station A, the CC
Process (3) is executed. The contents are shown in 2 of FIG. 5(b). First, the transfer call flag TR3 of the ACM signal is determined (60) of 2). If it is "1", it is determined that the call is a transfer call, and the process moves to process 61, and the call is terminated. Signal CL F (C1ear-F
forward signal) to the exchange, and then releases the trunk connected to exchange B, which had been captured until then. Next, we will analyze the DNc of the ACM signal.
), if it is the local station, it seizes extension d and sends a ringer-RG (68), and sends a ring hack tone RBT to extension terminal a on the calling side of exchange A through the network (68).
69).

If it is determined in the above step 63 that it is another station (in this case, exchange C), the trunk for the trunk line to exchange C is acquired (step 64), and the calling signal IA is sent to station C.
Send M.

In response to this CC processing (3) at station A, station B, which is the call transfer source, receives the call clearing signal CL F and performs CC processing (4).
) is carried out. As shown in FIG. 5(b), station B opens the trunk of the trunk line connecting to station A.

On the other hand, at station C, by receiving the calling signal TAM,
Process C (5) is executed. This process is performed when the transfer destination is station C according to processes 63 to 65 in FIG. 5(b), and first, as shown in FIG. and sends out the ringer RG, and connects the network NW.
() via rank PTCc) to send a ring hack tone RBT to the inner vA terminal a,
2) Send an acknowledgment signal ACM to the individual.

When station A receives the ACM signal from station C, processing (5) is performed. As shown in FIG. 5(b), the CC of station A bidirectionally connects the path between the trunk POGd passing through the network and the extension terminal a to form a communication path.

When the extension terminal responds (off-footer) to the ringer RG at station C, CC processing (7) is performed.

As shown in FIG. 5(b), when the ringer RG is stopped upon detection of a response, the ring hack tone RBT is released (74). Next, the paths of the trunk PICc and the extension terminal C are bidirectionally connected through the network NW, and a response signal ANN (An needle signal no.
char8e) is sent to station A (76), and station A detects the response and monitors the call status.

Next, execution sequence 2 of the trunk line variable call forwarding service shown in FIG. 4 will be explained.

Sequence 2 is the CC processing (3) in the sequence shown in Figure 3.
) shows the sequence when the transfer destination is local station A, CC processing (1) to (4) is the same as in Fig. 3, and as shown in steps 67 to 69 in Fig. 5(b). Tilt capture your own extension terminal d, which is the transfer destination, and connect it to the ringer.
Rc is sent to ring bank 1 to extension terminal a on the calling side.
-- After sending the RB T, when the extension terminal d responds, CC processing (8) is performed. The contents are shown in Figure 5 (2])
As shown in (c), the ringer RG is stopped, the ring hack tone RBT is opened, and the paths between the extension terminals a and d are bidirectionally connected through the network NW of station A.

FIGS. 6 and 7 show the control according to the present invention of execution sequence 1 and execution sequence 2 of the trunk line variable absent transfer service explained above as mutual relationship diagrams of exchanges A, B, and C. , respectively.

indicates the connection arrangement with the destination exchange at the time of call origination, and the port indicates the connection arrangement with the transfer destination.

This figure is FIG. 8 (b) which is an explanatory diagram of the conventional method.

When compared with the connection arrangement (d), it is clear that the connection arrangements of FIGS. 6(b) and 7(b) according to the present invention can use fewer trunk lines.

[Effect of the Invention 1] According to the present invention, in the trunk line variable call forwarding control system, the trunk trunk and line connected to the call forwarding station are released after transfer, so that the call loss rate for the call forwarding station is low. This allows lines and trunk trunks to be used effectively.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is an embodiment configuration diagram,
FIG. 3 shows the execution sequence 1 of the trunk line variable call forwarding service according to the embodiment. FIG. 4 is a diagram showing the execution sequence 2 of the trunk line variable call forwarding service of the embodiment, and FIG. 5 (
a) and FIG. 5(b) are process flow diagrams of processes (1) to (8) performed by the central controller CC during the execution sequence,
FIG. 6 is a connection layout diagram of execution sequence 1, FIG. 7 is a connection layout diagram of execution sequence 2, and FIG. 8 is an explanatory diagram of a conventional system. In FIG. 1, 10 to 12: exchanges A, C, B 13: exchange section I4; signal transmitting/receiving means 15: flil control section 151: transfer registration determination means 152: transfer control signal creation means 153: transfer control signal detection means 154: Transfer path disconnection means 155: Transfer transmission means 16: Memory

Claims (1)

[Scope of Claims] When the extension terminal of the first switching center specifies the extension of the second switching center as the transfer destination and registers trunk line variable absent transfer, another switching center sends the extension terminal of the first switching center to the extension terminal of the first switching center. In a trunk line absent transfer control method in which a call is transferred to a transfer destination of the registered second switching center when a call arrives at a registered extension terminal, the control unit (15) of the switch Transfer registration determining means (151) determines whether or not the registration is present, and if registered, transfer control signal generating means (152)
A transfer control signal with forwarding destination information (DNc) is created by the signal sending/receiving means (14) and sent to the other exchange on the originating side, and the control unit (15) of the other exchange on the originating side performs the transfer control. The trunk line variable absence is characterized in that, upon reception of a signal, the connection with the first switching center is disconnected, and then the originating terminal is connected to the transfer destination terminal of the transfer destination second switching center. Transfer control method.