JPH0479595A - Extension route setting method for building exchange system - Google Patents

Abstract

PURPOSE:To decrease the busy rate of a line for extension by connecting two lines for line wire connected to two floor exchanges, respectively at a center exchange, and performing the connection of loop back extension communication. CONSTITUTION:When the connection of the extension communication between the floor exchange 11 on one side and the floor exchange 11 on the other side is disabled by the busy of the line 13 for extension, the two lines 14 for line wire connected to the two floor exchanges respectively, are connected for the loop back extension communication at the center exchange 12. Therefore path P04, P03 are comprised so as to be loop-backed in the center exchange 12, which enables extension speech between a subscriber A and a subscriber B to be performed via a line route. Thereby, it is possible to decrease the generating rate of busy, extension line.

Description

[Detailed Description of the Invention] [Summary] A plurality of floor exchanges, a center exchange that centrally controls these floor exchanges and connects external lines via a central office line, and a connection between the floor exchanges for internal line communication. In an in-building switching system that has extension lines connected and external lines connected between each floor exchange and the center exchange, an extension line to be connected between one floor exchange and another floor exchange. When communication becomes unreachable due to the extension line being busy, the said 2
In this system, two external lines connected to two floor exchanges are looped back at the central exchange to connect the internal lines, thereby reducing the busy rate of the internal lines.

[Industrial application field]

The present invention provides for a plurality of floor exchanges, a center exchange that centrally controls the plurality of floor exchanges and connects outside lines via a central office line, and a center exchange that performs internal line communication between desired floor exchanges. The present invention relates to an in-building switching system having an extension line connected to a central switchboard, and an outside line line connected between each floor switchboard and a center switchboard, and particularly to a method for setting extension lines 1 to 5 in this system.

A distributed installation type that installs switchboards, that is, floor switchboards, on each floor, taking into consideration the dispersion of the risk of failure, the maintenance of security, and the demands of dozens of tenants in a super-large building. The configuration of the building's second building exchange system has already been implemented.

In this system, the economic efficiency of switching equipment and the outside line or exclusive use of each tenant! Taking into consideration the effective operation of FFP and traffic links, only one switch is required for the external line (including leased line) interface.

The present invention specifically describes extension communications between floor exchanges.

[Prior Art] FIG. 3 is a diagram showing the configuration of a known in-building exchange system. In this figure, 11 is a floor switch (FS).
or 5ta1.1on) and are installed on each floor (the figure shows examples of FS, ~FS, and H). Each floor exchange 11 accommodates a large number of subscribers thereunder. However, in the figure, for the sake of simplicity, one jJ
Ii1 Persons A, B, C and D not shown.

All floor replacements [11 is one center exchanger (C3
: Center 5tation) 12, and the center exchange [72 is connected to L via central line I9.
8 (1, oca ]Switch) Connect to the exchange 1
．． Make an outside line connection. However, instead of this LS exchange, a normal private branch exchange (PBX) may be connected.

(/I) The above-mentioned outside line connection is performed via an outside line line 14 provided corresponding to each floor exchange.

In a building, the same company (same tenant 1~) often occupies multiple floors. In this case, the dialing format for communication between floors is the same extension number format as within the same floor, but the communication format is a general centralized exchange that uses extension lines installed between floors. The connection form is the same as for outgoing and incoming calls. In the diagram, companies P, Q, and P are shown as tenants, and among these, company P occupies multiple floors. Therefore, the floor exchanges 11 in these two companies are connected by an extension line 13. The control of calling and receiving calls for internal lines and calling and receiving calls for external lines is performed by a central control unit (COH5) provided for each floor switchboard 11 and a main memory (MM) 1 that cooperates with the central control unit (COH5).
6, and a central control device (
COH2 and the main memory ff (MM) that cooperates with it
For example, a common line signaling system (CCITT No. 7) is used between these central control units CC.
A common line link is formed under.

[Problems to be Solved by the Invention] Figure 4 shows the extension route 1- in the in-building switching system J.
FIG. 2 is a diagram showing an example of the above, in which a bus for extension communication formed between subscriber A and subscriber B is shown as a dotted line P.

For example, when subscriber A makes an extension call to subscriber VB, the dotted line bus P must be formed along the extension line 13. In this case, in the current inter-floor communication for extension calls, the extension line (usually several 1
If all 13 (0 or more) are in use by other subscribers, the calling subscriber (in this case A
), the corresponding floor switch 11 transmits a busy tone.

When this busy tone is returned, subscriber A has to wait until other subscribers have finished using the service, causing a problem in his work.

In view of the above problems, an object of the present invention is to provide a method for setting an extension route in an in-building switching system that can further reduce the probability of occurrence of two consecutive busy extensions.

[Failure to solve the problem]

FIG. 1 is a diagram for explaining the present invention in detail. When all the extension lines are busy and the above-mentioned extension communication path cannot be formed (indicated by digits), the external line 14 of the floor exchange IF 54 Path P according to. 4 and floor exchange iFS, path P by external line 14. 3 to set an extension route equivalent to the extension communication path P8 described above.

(For use) The conventional outside line 14 is connected only to the central office line 19.

On the other hand, according to the present invention, the above path P. .

and P. , is folded back within the center exchange 12,
As a result, an extension call between subscriber A and subscriber B is made via the outside line route.

If our external line is occupied by an external call, of course the above detour path (P03.P0
4) The extension call is not successful. However, it is known from experience that the probability that both the extension line 13 and the outside line 14 become busy is low, and a considerable number of internal line busy situations can be relieved by the outside line route.

However, if the frequency of using the outside line line due to a busy internal line increases, the probability that the external line will be busy during the original external line communication will increase.

Therefore, preferably, the center exchange 12 monitors the usage status of each outside line line 14, and allows the above-described callback at the center exchange 12 only when the usage rate of each outside line line is less than a predetermined value. Do it like this. In addition, the above usage status monitoring is carried out by allocating a memory area corresponding to each external line in the main memory (MM) 18,
For example, this can be achieved by setting a flag of 1 for use and 0' for non-use in the corresponding memory area.

[Embodiment] FIG. 2 is a diagram showing an example of a signal sequence implemented under the present invention. This signal sequence shows what is implemented under common line signaling. Further, this signal sequence shows a sequence when extension communication via the detour route 1- via the outside line becomes possible. The meanings of the symbols in this figure are as follows.

FS4: Floor exchange to which subscriber A belongs FS3: Floor exchange to which subscriber B belongs IAI: Address signal with additional information ACJ: Address completion signal with additional information ANI: Response signal with additional information CLF: Disconnect signal RLG: Recovery completion signal Below , an overview of call processing will be explained. It is assumed that the speech line and the signal link line are configured in a corresponding network relationship. Further, as in the above example, extension communication from subscriber @A to subscriber B will be explained as an example.

- Subscriber A of floor exchange FSa dials subscriber B's telephone number in the usual extension number format.

- The floor exchange FS translates and analyzes the number received from subscriber A, and if it is identified as an extension call, reads and analyzes the subscriber data of subscriber B from the received number information for incoming call connection.

(2) Analyzing the accommodation location information in the subscriber data and determining that the subscriber is accommodated in an exchange on another floor. If the subscriber is within the local exchange (+734), the subscriber's empty/busy status is checked after this analysis.

After determining that the subscriber is accommodated in an exchange on another floor, first, in order to transmit the received number, outgoing route hunting processing between the floors is performed based on the accommodation position information in the destination subscriber data.

When the present invention is applied, the outgoing route is already in use by all other callers, and the detour route I processing according to the present invention is carried out after the hunt is unsuccessful.

(2) After the hunt fails, conventionally a process is executed to send a connection failure signal to subscriber Δ, but according to the present invention, a detour process is activated. This detour process first begins with the FS
, calculate the empty line of external route I. from the exchange to the center exchange 1 (C3) 1.2. Thereafter, it is determined whether the number of free lines is greater than or less than a predetermined percentage of the total number of installed lines, and hunt processing is performed only when there are more free lines at the present time. This is a line sequestration algorithm that prioritizes external calls.
This corresponds to monitoring the usage rate of the external line described above.

■ After hunt is enabled, calculate the common line signal link and signal destination information from the relevant hunt I/line.

Thereafter, an address signal is edited and created using FS information on the calling side, tenant information, called party number on the called side, information on the floor where the called party is accommodated, information on the calling and receiving stations, and searched line information. After it is created, it is sent to the center exchange C8 via the common line.

- After receiving the address signal, the center exchange C8 translates and analyzes the address signal. Information on extension numbers is set in the translation table for the detour processing of the present invention. As a result, if it is determined that it is an internal call rather than an external call, the called party's floor information is extracted from the received address signal, and a route to the F1A exchange IF 53 is hunted using the floor information. Hunt processing is also a detour call, so the above-mentioned external call priority line acquisition algorithm is used.After hunting becomes possible, the common line signal link and destination station information are calculated from the relevant Han I-line.After that, F After creating the address signal by partially changing the information in the address signal received from Sa (changing the originating/destination signal station, line information, etc.), it is transmitted to the exchange FS over the common line.

After receiving the address signal, the floor switch FS3 performs translation analysis, and if it is a normal extension number, reads subscriber data of subscriber B from the extension number information and analyzes it.

■ Analyze the accommodation location information in the subscriber data, and if it is determined that the subscriber is within the own exchange (FS, l),
Check the status of the blockage. If vacant, use center exchange C
The address completion signal is sent to 8. After that, a process for transitioning to the calling state is started. In this calling process, a ringing tone is sent to the called party (+3) and a ring hack tone signal is sent to the calling party (A).

(2) When the center switch C8 receives the address completion signal, it transmits the address completion signal to the floor switch FS4 which is the originator. Thereafter, the input and output terminals for forming a communication bus are connected to enable communication.

■ When the floor switch FS4 receives the address completion signal,
Connect the output terminal and subscriber terminal to enable communication.

(2) When the called party (B) responds, the response signal is transmitted to the originating exchange FS4 via the center exchange C8 to establish a telephone conversation state.

@If the caller (A) disconnects first, each signal CLF and RLG shown in the sequence diagram will be transferred to FS.

FS4 release processing is executed.

(Effects of the Invention) As explained above, in the case of an in-shell exchange connection process, it simply sends a connection unavailable signal (busy tone) and ends, but according to the present invention, an in-building exchange connection process ends. By skillfully utilizing the configuration and furthermore, by suspending the external line, it becomes possible to establish an equivalent extension call with a high probability, and the occurrence of an extension line busy can be considerably suppressed.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the present invention in detail, Fig. 2 is a diagram showing an example of a signal sequence implemented under the present invention, and Fig. 3 is a diagram showing the configuration of a known in-building switching system. , FIG. 4 is a diagram showing an example of an extension route within the in-building switching system. In the figure, 11... Floor switchboard, 12... Center switchboard, 13... Extension line, 14... External line, 15, 17... Central control unit, 16, 18... Main Storage device, 19... central office line, P
, . . . bus for internal communication, P ol + P C4 . . . bus for external lines.

Claims (1)

[Claims] 1. A plurality of floor exchanges (11), a center exchange (12) that centrally controls the plurality of floor exchanges (11) and connects external lines via a central office line (19); an extension line (13) connected between the floor exchanges for internal communication between the floor exchanges; and an external line connected between each of the floor exchanges (11) and the center exchange (12). In the method for setting an extension route in an in-building switching system having a line for the extension (14), the extension communication to be connected from one floor switch (11) to the other floor switch (11) is When connection becomes impossible due to the line (13) being busy, the two outside line lines (14) connected to the two floor exchanges are connected to the center exchange (12).
1. A method for setting an extension route in an in-building switching system, characterized in that the extension communication is connected back at the terminal. 2. When returning the two external lines (14) at the center exchange (12), the usage status of each external line (14) is monitored and the usage rate of each external line (14) is checked. 2. The extension route setting method according to claim 1, wherein the callback is executed only when the number is less than a predetermined value.