JPH05260092A - Representative selection method for private branch exchange system - Google Patents

Abstract

PURPOSE:To identify the terminals that belong to an interface group of a representative group when a packet call is received by the representative group of a private branch switchboard from an ISDN. CONSTITUTION:When a packet call is received, the D-channel call control signal procedure SQ is carried out between a private branch switchboard 2A and an ISDN 1. Then the switchboard 2A checks the normal state of an interface group a1 of a representative group 3A. When the normal state of the group a1 is confirmed, the TEI check request messages are sent to all terminals of the group a1. Meanwhile each terminal sets a packet/non-packet terminal identification code in an information field of a TEI check answer message and then transmits the identification code to the switchboard 2A. If a packet terminal is connected in the group a1, the switchboard 2A connects the call and transmits a calling packet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interface group selection method in a representative selection service of a private branch exchange system for integrated service digital networks (hereinafter referred to as ISDN).

[0002]

2. Description of the Related Art A representative selection service is an additional function of ISDN and forms a plurality of users as one representative group so that when a call comes in, it is distributed to each user in the representative group. By providing
This function distributes incoming calls and increases the possibility of avoiding recalls by the calling user.

FIG. 5 shows a system configuration diagram of a private branch exchange system constituting a representative group in the representative selection service.

In FIG. 5, 1 is ISDN and 1L is IS.
DN line, 2 private branch exchange connected to the ISDN by the ISDN line 1L, 3A interfaces group a _1, a _2, ......, a representative group composed of a _n,
And 3B are interface groups b ₁ , b ₂ , ...,
This is a representative group composed of b _m .

As shown in the inset S of FIG. 5 in this interface group a ₁ , for example, a plurality of terminals a ₁₁ , a ₁₂ , ..., A _1n are included in the interface group a _1.
Are point-multipoint connected. The interface group a _{2 is} also similarly point-multipoint connected.

It is assumed that the a ₁ , a ₂ , ..., A _n and b ₁ , b ₂ , ..., B _m at the same time represent the ISDN number of each interface group.

[0007] _{L a1, L a2, ......,} L an each interface group a _1, a _2, ......, campus ISDN line to a _n, and _{L b1, L b2, ......,} L bm each interface Private ISDN lines to private lines to groups b ₁ , b ₂ , ..., B _m .

In the configuration of the representative group, the representative selection method in the conventional example is that the private branch exchange 3 is used for ISDN.
Set by registering as a representative.

The representative parent number (pilot number) of the representative group 3A is a ₁ . Therefore, a ₂ , ..., A _n are representative numbers.

FIG. 6 shows a representative selection method in the conventional example by a D channel link access procedure (LAPD).

In FIG. 6, 1 is ISDN, 2 is a private branch exchange, and 3 is an interface group selected from the representative group 3A (for example, a ₁ ).

SQ is a D channel call control signaling procedure,
A UI frame (call setup) from the ISDN 1 to the private branch exchange 2 and an I frame (response) from the private branch exchange 2 to the ISDN 1, an I frame (release) from the ISDN 51 to the private branch exchange 52, and an I frame (release) from the private branch exchange 52 to the ISDN 51 ( Release completed) and ISDN 51 to private branch exchange 5
2 I frame (X.25 incoming call packet CN).

Next, the representative selection method in the conventional example will be described. In the above-mentioned conventional example, the packet incoming call from the calling terminal (particularly not shown) is changed from ISDN1 to ISDN.
In the case of the private branch exchange 2 via the line 1L, the call control signal procedure SQ on the D channel is performed between the ISDN 1 and the private branch exchange 2 as shown in FIG. 5, and the destination address thereof is the representative group 3A. It is assumed that the representative parent number (pilot number) of is a ₁ .

In this case, the private branch exchange 2 has the interface groups a ₁ , a ₂ , ..., Which belong to the representative group 3A.
selecting a free channel in accordance with the selection order by sequentially search or round-robin fashion to a _n. In this case, the private branch exchange 2 determines that the selected interface group has the following eight states (all logical channel busy, failure, blocking, service order processing, incoming call suspension, communication suspension, temporary removal, interface busy). ).

The selected interface group is 8
If none of the two states
The private branch exchange 2 uses the representative selection function,
Select a specific representative group and select one of the interfaces
Group (eg, a ₁UI frame
Send (call setup).

In this way, when there is a packet incoming call, an empty interface group whose interface group in the representative group is neither of the above eight states is selected and the incoming call becomes possible.

If the selected interface group a ₁ is in any one of the above eight states, the process moves to the next interface group a ₂ .

If all the interface groups are in any of the above states, the private branch exchange 2 sends a restoration request packet (CQ) to the ISDN 1 as a call rejection operation. The ISDN 1 transmits a disconnection instruction packet (CI) indicating that the disconnection cause in this case is "rejection of incoming call" to the calling side.

[0019]

However, even if the state of the interface group is not in any of the above-mentioned states, only the non-packet terminal is connected to the selected interface group, or the packet terminal is disconnected. If it is present (for example, it is removed during operation), the UI frame (response) is not transmitted from the receiving terminal to the private branch exchange in response to the UI frame (call setting). The private branch exchange 2 retransmits the UI frame (call setup) a prescribed number of times (RTY in FIG. 6), but if the UI frame (response) cannot be received from the selected interface group (a ₁ ), a fixed time (time T ₃₀₃ ). After that, a restoration request packet (CQ) is transmitted to ISDN1 and the call is disconnected.

As described above, even though the selected interface group is not in any of the above eight states, even if a packet terminal is connected to another interface group of the same representative group and is in an idle state. The private branch exchange 2 disconnects the call without selecting the interface group.

The present invention solves the above-mentioned conventional problems, even when only non-packet terminals are connected to the interface group of the representative selection service, or even when the packet terminals are disconnected. , The interface group in the representative group can select another interface that does not have any of the above states.

[0022]

In order to achieve the above object, the present invention is representative of a private branch exchange system comprising a private branch exchange connected to an integrated services digital network (ISDN) and a plurality of terminals connected to the private branch exchange. In the selection method, when an interface group belonging to the representative group is selected when a packet call to the representative group is received, the private branch exchange requests a terminal termination point identifier (TEI) check request before controlling the call connection to each interface group. Send a message to each of the above interface groups, to which each terminal belonging to each interface sends to the private branch exchange a terminal termination point identifier (TEI) check response message containing information identifying a packet terminal or a non-packet terminal. It is the one.

[0023]

Therefore, according to the present invention, the private branch exchange is an ISDN.
When an incoming call packet having the representative parent number corresponding to the representative selection as the destination address is received, even if there is no packet terminal on the selected interface group in the empty state, that fact can be detected. Instead of disconnecting the call, the next interface group can be reselected and an incoming call packet can be transmitted if a packet terminal exists there.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A system configuration diagram of a private branch exchange system constituting a representative group in one embodiment of the present invention is the same as FIG. 5 used in a representative selection method of a conventional example. FIG. 1 shows a representative selection method according to an embodiment of the present invention by a D channel link access procedure (LAPD) as a control procedure between a private branch exchange and a terminal.

[0025] In FIG. 1, 1 is ISDN, 2A is private branch exchange, 3 is an interface group a ₁ of the first representative selected representative groups, terminal a _11, a _12, as shown in the inset S in FIG. 5 , ..., point-multipoint connection with a _2n , 4 is another interface group a ₂ of the representative group, which is terminals a ₂₁ , a ₂₂ ,.
It is connected to a _2m point / multipoint. The terminal a _2m of the interface group a ₂ is a packet terminal.

FIG. 2 shows a processing flow of a method of selecting a representative of a private branch exchange in one embodiment of the present invention.

FIG. 3 is a block diagram of a terminal termination point identifier (TEI) check request message in Layer 2 of the control procedure between the private branch exchange and the interface group in the representative selection method of the above embodiment, and FIG. 4 is an interface for the TEI request message. FIG. 6 shows a block diagram of a terminal termination point identifier (TEI) response message from a group to a private branch exchange.

Next, a representative selection method according to an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, ISDN 1 and private branch exchange 2
When receiving a call with A, the D-channel call control signal procedure SQ (step S in the processing flow of FIG. 2) is performed as in the conventional example.
1, hereinafter S number corresponds to each step of the processing flow of FIG. 2).

Next, in the private branch exchange 2A, the selected interface group has the following eight states (all logical channel busy, failure, blocking, service order processing, incoming call suspension, communication suspension, temporary removal, Interface busy) is checked (step S2).

If none of the above eight states (the interface state is called normal) (step S3)
In addition, the private branch exchange 2 performs layer 2 frame configuration to the interface group by its representative selection function (step S4), and TEI is set to one interface group (for example, a ₁ ) of the selected representative groups.
A UI frame (TEI check request) is sent as a check request message (step S5).

At this time, the service access point identifier (SAPI) 3 of the address field 31 in the TEI check request message format shown in FIG.
1a is set to 63, the terminal end point identifier (TEI) 31b is set to 127 by broadcasting mode, the message type 32a of the information field 32 is set to TEI check request, and the operation display (A _i ) 32b is set to 127 and transmitted. ..

When the interface group a ₁ receives a UI frame (TEI check request) in the broadcast mode as the TEI check request message, each terminal of the interface group a ₁ sequentially sends a UI frame (TEI check response) as a TEI check response message. )
To the private branch exchange 2.

The structure of the UI frame (TEI check response) as the TEI check response message is, as shown in FIG. 4, that the message type 41a of the information field 41 is set to TEI check response, and the operation display (A _i ). Extension bit 41 of bit 1 (E) of field
Using b, a terminal identification code field is provided next to the operation display (A _i ) field, and the packet / non-packet terminal identifier 41c is set therein for each terminal.

When the private branch exchange 2 receives the UI frame as the TEI check response message from each terminal in the interface group for the TEI check request message (step S6), it analyzes the TEI check response message (step S7). The packet terminal / non-packet terminal is identified by the terminal identification code field, and if the result is a packet terminal (Yes in step S8), an incoming operation is started (step S9).

As shown in FIG. 1, the TEI of all terminals in an interface group (for example, a ₁ )
If all the results of checking the terminal identification code field of the UI frame as the check response message are non-packet terminals (No in step S8), another interface group is selectively set (for example, as shown in FIG. 1). Interface group a ₂ ) (step S10), and then the state of interface group a ₂ is checked. If the result is normal, the TEI check request message indicates that the broadcast mode U
The I frame (TEI check request) is transmitted to the interface group a ₂ . The private branch exchange 2 sequentially performs packet terminal / non-packet terminal identification by the terminal identification code field of the UI frame as the TEI check response message from each terminal of the interface group a ₂ , and as a result, if it is a packet terminal, Enter the incoming call operation.

In this way, if there is an interface group with no packet terminal, the TEI check request message is sent to another interface group of the representative group.

If all the interface groups are checked and there is no non-packet terminal in all, the private branch exchange 2 sends the restoration request packet (CQ) to the ISDN 1 for the first time to disconnect the call.

[0039]

As is apparent from the above-described embodiment of the present invention, the private branch exchange 2 has the interface switch when selecting the interface group in the representative group of the representative selection service.
Since the presence or absence of the packet terminal on the group is confirmed, even if the interface group including only the non-packet terminal is first selected as the representative group interface group, the call is not immediately disconnected there.

[Brief description of drawings]

FIG. 1 is a control procedure of a representative selection method according to an embodiment of the present invention.

FIG. 2 is a processing flow of a method of selecting a representative of a private branch exchange in the above embodiment.

FIG. 3 is a terminal termination point identifier (T) between a private branch exchange and an interface group in the representative selection method of the above embodiment.
EI) Check request message configuration diagram.

FIG. 4 is a structural diagram of a terminal termination point identifier (TEI) response message in response to the TEI request message.

FIG. 5 is a system configuration diagram of a private branch exchange system that constitutes a representative group in the representative selection service.

FIG. 6 is a D channel link access procedure (LAPD) of a representative selection method in a conventional example.

[Explanation of symbols]

1 ISDN 1L ISDN line 2A private branch exchange 3 interface group a ₁ 4 interface group a ₂ 31 TEI check request message address field 31a the address field service access point identifier area 31b the address field terminal termination point identifier area 32 TEI check request Information field of message 32a Message type area of the information field 32b Operation display area of the information field 41 TEI check response message information field 41a Message type area of the information field 41b Extended bits of operation display area of the information field 41c The information Terminal identification code in the field
area

Claims (1)

[Claims] 1. Integrated services digital network (ISDN)
A private branch exchange system connected to a private branch exchange and a representative selection method in a private branch exchange system composed of a plurality of terminals connected to the private branch exchange, wherein when selecting an interface group belonging to the above-mentioned representative group when a packet call arrives at the representative group, The private branch exchange sends a terminal termination point identifier (TEI) check request message to each of the above interface groups prior to controlling the call connection to each of the interface groups, whereas each of the terminals belonging to each interface is a packet terminal or a non-packet terminal. A representative selection method in a private branch exchange system, which comprises transmitting a terminal termination point identifier (TEI) check response message including information for identifying the private branch exchange to the private branch exchange.