JPH05153647A - Exchange - Google Patents

Abstract

PURPOSE:To decrease the probability of call loss and increase the stability of originating and terminating connection operation by holding the occurrence probability of an origination/termination conflict not extremely high even if origination traffic becomes large. CONSTITUTION:A means 13a which detects the frequency of termination from a line wire is provided and detects the frequencies of termination as to plural line wires OL11-OL16 constituting an line wire group OL1. The line wires OL11-OL16 which constitute an idle chain are rearranged in the increasing order of the frequency of origination according to the detection result and when a line wire origination request is made, the line wire which has the lowest frequency of use is selected according to the array of the idle chain and connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a private branch exchange, such as a dial-in system, for performing an outgoing / incoming connection process by selecting an external line in a standby state from a plurality of grouped external lines. ..

[0002]

2. Description of the Related Art Generally, in a private branch exchange adopting a dial-in system, DID (Direct in dialing) or DIL is used.
(Outline) A plurality of outside lines are grouped for each type of dial-in system such as (Direct in line), and an outside line used for making and receiving calls is selected for each grouped outside line group.

By the way, one of the factors that must be taken into consideration when selecting the outside line is reduction of call loss. That is, in a system in which an outside line is shared for originating and terminating without being divided into an outgoing line and an incoming line, two exchanges facing each other may select the same outside line at substantially the same time to perform outgoing / incoming processing. In such a case, calls from the respective exchanges collide on the outside line, and one or both of the calls are not processed, resulting in a call loss.

Therefore, conventionally, for example, a plurality of outside lines are uniquely arranged in a row in advance, and when the outside line transmission occurs, the outside lines are selected in a fixed order from the outside line sequence, and the selection order of the outside lines is set. A system is used in which the exchanges are set to be opposite to each other. However, in such a system, it is necessary that both of the exchanges facing each other adopt the same system, and further perform the selection operation in cooperation with each other. Therefore, sequential design is indispensable when constructing a system, and system design becomes very troublesome.

On the other hand, there is an idle chain system as another external line selection system. In this method, for example, for each grouped outside line group, a plurality of waiting outside lines are arranged in a line (idle chain) and managed, and the outside line used for incoming calls is placed at the end of the line. When a call is sent back or sent, an outside line is always selected and used from the head of the line, and the line is returned to the head of the line after the line is released. In such a system, an external line that is easily used for incoming calls and an external line that is often used for outgoing calls are automatically separated from each other in the arrangement of external lines, so that a call-in / out collision is less likely to occur and the call loss rate is lowered. Further, since it is sufficient for the exchanges to be managed independently, it is not necessary to perform the selection operation in cooperation between the exchanges facing each other, which simplifies the design at the time of system construction.

[0006]

However, there are the following problems with the conventional exchanges adopting the idle chain system. That is, when the outgoing traffic is relatively low, the external line mainly used for outgoing call and the external line mainly used for incoming call are managed as if they were separated as described above, so that the occurrence of incoming and outgoing collisions is prevented. Certainly reduced. However, if the outgoing traffic becomes high, the external line, which was mainly used for incoming calls, is used for outgoing calls, so the state of the chain is substantially destroyed, and as a result, the probability of occurrence of incoming and outgoing collisions increases.
Further, once an external line that is easily used for incoming calls is once used for outgoing calls, the external line is returned to the head of the line after the line is released, and thus the probability of collision between incoming and outgoing calls increases.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent the occurrence probability of incoming and outgoing collisions from significantly increasing even if the traffic of outgoing calls becomes high, thereby reducing the call loss rate. It is therefore to provide an exchange capable of performing stable incoming and outgoing connection operations.

[0008]

In order to achieve the above object, the present invention provides means for detecting the frequency of use of an outside line in an exchange that accommodates at least one outside line group in which a plurality of outside lines for outgoing and incoming calls are grouped. The use frequency of each of the plurality of outside lines forming the outside line group is detected by this means, the order of selection of each outside line is changed according to the detection result, and the use request of the outside line is generated. In this case, an outside line that is rarely used is selected according to the arrangement of the outside lines.

Further, according to the present invention, by the use frequency detecting means,
An incoming call use frequency is detected for each of a plurality of outside lines forming an outside line group, and the selection order array of each outside line is rearranged according to the detection result in ascending order of incoming call use frequency, and an outgoing call request to the outside line is generated. Each external line is also selected in order from the external line having the lowest frequency of use of incoming calls, according to the arrangement of the external lines.

[0010]

As a result, according to the present invention, for example, an array of a plurality of external lines forming an idle chain is rearranged according to the frequency of incoming calls, and when an outgoing call occurs, an external line with a low frequency of incoming calls is always selected. Will be used.
Therefore, even if the outgoing traffic is high and an external line that is easy to receive is used for outgoing, the external line is not returned to the head of the line after being released, but is returned to the rear of the line. become. Therefore, the outside line that is easily used for incoming calls is kept in a position that is not easily selected for outgoing calls, thereby reducing the occurrence of incoming and outgoing collisions and suppressing the call loss rate to a low value.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram showing a configuration of an electronic private branch exchange according to an embodiment of the present invention, and 10 shows an exchange main body. The exchange main body 10 includes a time switch 11, a time switch control circuit (TSC) 12, a central control circuit 13, and a plurality of line circuits LC1 to LCn, and each of the line circuits LC1 to LCn has an extension IL1. ~ Extension terminal TEL such as a telephone via ILn
1 to TELn are connected.

The exchange main body 10 also accommodates two outside line groups OL1 and OL2. These outside lines OL
1 and OL2 are a plurality of outside lines OL11 to OL1 respectively.
m, OL21 to OL1k are grouped, and are connected to, for example, different central office exchanges (not shown) and are used to perform a dial-in service by the DID system with these central office exchanges. Each of the outside lines OL11 to OL1
m, OL21 to OL1k are trunk line trunks TRK11, respectively
-TRK1m, TRK21-TRK2k are connected to the time switch 11.

The time switch control circuit 12 switches and controls the time switch 11 in accordance with an instruction from the central control circuit 13, whereby the line circuits LC1 to LCn are controlled.
And trunk line trunks TRK11-TRK1m, TRK21-
The line circuits LC1 to LCn are selectively connected to the TRK2k. Line circuits LC1 to LCn
Performs various interface operations with respect to the extension terminals TEL1 to TELn such as detection of outgoing signals and dial signals and transmission of incoming signals. Local line trunk TRK1
1-TRK1m and TRK21-TRK2k send and receive various control signals relating to the originating and terminating connection with the central office switch via the outside lines OL11-OL1m, OL21-OL2k, respectively.

The central control circuit (CC) 13 includes:
Main memory (MEM) composed of RAM, for example, via the bus
14, a disk control circuit (DC) 15 and an external interface circuit (I / F) 16 are connected. A magnetic disk drive (HDD) 20 as an external storage device is connected to the disk control circuit 15. The magnetic disk drive device 20 uses, for example, a hard disk (HD) as a storage medium, and a nonresident program is stored in the storage area of the hard disk. Further, the external interface 15 is connected with an input / output device 30 including a personal computer (PC). The input / output device 30 is used as an operation terminal when changing a resident program, a non-resident program, and various control data.

The central control circuit 13 includes, for example, a microcomputer as a main control section,
As a control function related to the operation for selecting each of the outside lines OL11 to OL1m and OL21 to OL2k, the incoming number counting means 13a and the idle chain managing means 13b are provided.
And an outside line selecting means 13c. The incoming call number counting means 13a is used for each of the outside lines OL11 to OL1m and OL21 to.
The number of incoming calls is counted for each OL2k. These count values are stored in the count value storage area provided in the main storage unit 14. Also, idle chain management means 13
In b, the outside lines in the standby state are arranged in a line for each of the outside line groups OL1 and OL2, and the order of this arrangement is managed according to the result of counting by the incoming number counting means 13a in the order of the smallest number of incoming calls. Information about the arrangement order of the idle chains is stored in the main storage unit 14. Further, the outside line selecting means 13c selects the outside line located at the head among the outside line strings managed by the idle chain managing means 13b, when the extension terminals TEL1 to TELn make a call request to the outside line groups OL1 and OL2. It is used for outgoing connection. Next, the operation of selecting an outside line will be described based on the above configuration. It should be noted that the outside line group OL1 will be described here assuming that the number of outside lines is six.

First, in the initial state immediately after the initial reset of the exchange main body 10, each of the outside lines OL11 to OL.
The number of incoming calls of 16 is all “0”. Therefore, the outer lines OL11 to OL16 are arbitrarily arranged in the numerical order as shown in FIG. 4A, thereby forming the initial state of the idle chain.

In this state, it is assumed that an incoming call arrives from a central office (not shown) via the outside line OL14, for example. Then, the central control circuit 13 starts the connection control for the incoming call and executes the idle chain management control for the incoming call according to the procedure shown in FIG. That is, first, in step 2a, the number of incoming calls up to that time of the outside line OL14 in which the incoming call has occurred is read from the main storage unit 14,
It is determined whether or not the number of incoming calls reaches a preset maximum value, for example, "10". If the result of this determination is that the number of incoming calls has not reached the maximum value, it is determined that there is no concern that the count value of the number of incoming calls will overflow, and the process proceeds to step 2b, where the number of incoming calls is counted up (+1), and The new number of incoming calls after counting up is stored in the corresponding area of the main control unit 14 instead of the old value up to that point. If it is determined in step 2a that the number of incoming calls on the outside line has reached the maximum value "10", the process directly proceeds to step 2e without counting up to prevent overflow of the number of incoming calls.

Next, the central control circuit 13 reads the number of incoming calls of all the outside lines OL11 to OL16 from the main control unit 14 in step 2c, and determines whether or not the number of incoming calls is "1" or more. As a result of this determination, all outside lines OL11
~ If the number of incoming calls of OL16 has not reached "1" or more, the process goes to step 2e to temporarily remove the outside line OL14 where the above-mentioned incoming call occurs from the idle chain. Prevent OL14 from being selected.

Then, during the use of the outside line OL14, the central control circuit 13 executes the above-mentioned outside line OL14 in step 2f.
Monitor for the release of. Then, when the call using the outside line OL14 as a communication path ends and the outside line OL14 is released thereby, the process goes to step 2g where the outside line OL14 is returned to the idle chain. Further, at this time, the central control circuit 13 causes the main control unit 14 to output the outside line O.
The numbers of incoming calls of all the outside lines OL11 to OL16 including L14 are read out, the values of the numbers of incoming calls are compared, and the order of arrangement of each of the outside lines OL11 to OL16 is rearranged in the ascending order of the number of incoming calls. Management information is stored in the main storage unit 14.

Similarly, the central control circuit 13 executes the idle management control at the time of incoming call each time an incoming call occurs on each of the outside lines OL11 to OL16. Therefore, the arrangement order of each outside line in the idle chain is managed such that the outside line having the smallest number of incoming calls is always arranged at the head position and the outside line having the largest number of incoming calls is arranged at the last position. FIG. 2B shows an example of the management state.

Further, in step 2c, when it is detected that the number of incoming calls of all the outside lines OL11 to OL16 becomes "1" or more as shown in FIG. 2 (c), the central control circuit 13 makes a step. 2d, the number of incoming calls of all outside lines OL11 to OL16 is uniformly counted down by "1" as shown in FIG. 2 (d), and the value of the number of incoming calls after this countdown is stored in the main control unit 14. Let As a result, an overflow of the number of incoming calls is suppressed without changing the value indicating the incoming call frequency between the outside lines OL11 to OL16.

On the other hand, it is assumed that a call request is issued from any extension terminal TEL11 to the outside lines OL11 to OL16 while the idle chain is being managed as described above. Then, as shown in FIG. 3, for example, the central control circuit 13 first reads the management information of the idle chain from the main memory 14 in step 3a, selects the outer line located at the head of the chain arrangement, and uses it for outgoing connection. For example,
If the idle chain is now in the state shown in FIG. 4D, the outside line OL11 is selected. The outside line OL11 selected for this call is taken off the idle chain until it is released.

While the outside line OL11 is in use, the central control circuit 13 monitors in step 3b whether or not the outside line OL11 is released, and when release is detected, the process proceeds to step 3c where the outside line OL11 is idled. Return to. Further, at this time, the central control circuit 13 reads out the number of incoming calls of all the outside lines OL11 to OL16 from the main control unit 14, and based on the value of the number of incoming calls, each of the outside lines OL11.
~ The order of arrangement of OL16 is rearranged in ascending order of the number of incoming calls. Then, the rearranged new idle chain management information is written in the main storage unit 14.

As described above, according to this embodiment, the arrangement of the outside lines in the idle chain is always rearranged and managed in the ascending order of the number of incoming calls. Therefore, the outgoing traffic becomes high, which causes, for example, the outside line OL14 or OL1 frequently used for incoming calls.
Even if 6 is selected and used for making a call, the outside lines OL14, OL16 are not returned to the head position of the idle chain after being released, and are arranged at the back of the idle chain according to the number of incoming calls. become. Therefore, when the outgoing call request is generated next time, the outside lines OL14 and OL16 which are frequently used for the incoming call are less likely to be selected, and as a result, the probability that the outgoing call and the incoming call collide with each other and the call loss is likely to occur. Will be reduced.

Further, in this embodiment, all the outside lines OL11 to OL.
When the count value of the number of incoming calls of 16 becomes "1" or more,
Since each count value is counted down uniformly, the number of incoming calls of each of the outside lines OL11 to OL16 becomes the maximum value and there is no difference, and as a result, it is possible to prevent the problem that the idle chains cannot be rearranged. .. That is, it is possible to prevent the idle chain from being saturated.

The present invention is not limited to the above embodiment. For example, in the above embodiment, all the outside lines OL11 to
When the count value of the number of incoming calls of the OL16 becomes "1" or more, each count value is uniformly counted down. However, periodically or every time the number of incoming calls of all outside lines exceeds a predetermined value. The number of incoming calls for each outside line may be cleared. In this case, if the order of arranging the idle chains is maintained in the state before clearing, the tendency of the incoming frequency of each outside line obtained before clearing can be maintained as it is.

Further, in the above embodiment, the case where the idle chain is controlled by the number of incoming calls of each outside line and this idle chain is used for selecting the outside line for outgoing call has been described. On the contrary, the idle chain is used for each outside line. The idle chain may be configured to be used to select an external line for incoming call, controlled by the number of outgoing calls.

In addition, the idle chain management control procedure and its control contents, the number of external lines constituting one external line group, the type of external line (a dedicated line other than the station line may be used), the configuration and type of the exchange, etc. Various modifications can be made without departing from the scope of the present invention.

[0029]

As described above in detail, according to the present invention, means for detecting the frequency of use of external lines is provided, and the frequency of use for each of a plurality of external lines forming an external line group is detected by this means. According to this detection result, the arrangement of the selection order of each outside line is changed, and when an outside line use request occurs,
By selecting an infrequently used outside line according to the arrangement of the above outside lines, it is possible to prevent the occurrence probability of incoming and outgoing collisions from significantly increasing even if the traffic of outgoing calls becomes high, thereby reducing the call loss rate. Thus, it is possible to provide an exchange that can perform stable outgoing / incoming connection operation.

[Brief description of drawings]

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

2 is a flowchart showing a control procedure and control contents of idle chain management control at the time of incoming call in the exchange shown in FIG.

3 is a flowchart showing a control procedure and control contents of outside line selection control at the time of making a call in the exchange shown in FIG.

FIG. 4 is a diagram used for explaining the operation of the idle chain management control at the time of incoming call shown in FIG. 2;

[Explanation of symbols]

10 ... Exchanger body, 11 ... Time switch (TS), 1
2 ... Time switch control circuit (TSC), 13 ... Central control circuit (CC), 13a ... Incoming number counting means, 13b ...
Idle chain management means, 13c ... Outline selection means, 1
4 ... Main memory (MEM), 15 ... Disk control circuit (D)
C), 16 ... External interface circuit (I / F), 20
... magnetic disk drive (HDD), 30 ... input / output device, LC1 to LCn ... line circuits, IL1 to ILn ... extensions, TEL1 to TELn ... extension terminals, OL1, OL2 ...
Outside line group, OL11 to OL1m, OL21 to OL2k ... Outside line, TRK11 to TRK1m, TRK21 to TRK2k
… Trunk line trunk.

Claims (2)

[Claims] 1. A switching frequency accommodating at least one outside line group in which a plurality of outgoing and incoming outside lines are grouped, and a use frequency detecting means for detecting a use frequency for each of the plurality of outside lines forming the outside line group. And an idle chain management means for varying the arrangement of the selection order of each outside line according to the detection result of the usage frequency detection means, and a management by the idle chain management means when a use request for the outside line occurs. A private branch exchange, comprising: an outside line selecting means for selecting an outside line that is less frequently used according to the arrangement of the outside lines. 2. The use frequency detecting means detects the frequency of use for incoming calls for each of a plurality of outside lines forming an outside line group, and the idle chain managing means sets an array of the selection order of the outside lines for the incoming calls. 2. The outside line selecting means rearranges the lines in order of increasing frequency of use, and when an outside line transmission request is made, the outside line selecting means selects an outside line having the lowest frequency of use of incoming calls according to the arrangement of the selection order of each outside line. Exchange described in.