JPH0318798B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a priority connection system for preferentially connecting interoffice lines for subscriber telephones having high priority.

[Background of the invention]

First, a conventional priority connection system will be explained with reference to a relay system diagram in FIG.

In the figure, 1 is the originating exchange (A office), 2 is the terminating exchange (B office), 3 and 4 are trunks (TRK) related to the inter-office circuit, 5 is the originating subscriber's telephone a,
Reference numeral 6 denotes a receiving subscriber's telephone set b, and 5' indicates another originating subscriber's telephone set c. In all of the following descriptions, for convenience, the subscriber's telephone is simply referred to as the subscriber.

Referring to FIG. 1, the connection from subscriber a of station A to subscriber b of station B will be explained.

The A station measures the trunk usage rate for the trunk group to the B station, and restricts outgoing connections if the usage rate exceeds a certain level. What is outgoing connection regulation?
Outgoing connections are regulated according to the priority order of the calling subscriber. For example, if a connection request is made from subscriber c of station A, which has a low priority, to subscriber b, of station B, while restricting outgoing connections, the connection is restricted, and at this time, When a subscriber requests connection of station B to subscriber b, the connection is made.

As described above, the conventional priority connection system determines whether or not a new connection can be established based on the usage rate of the trunk group and the priority order of the originating subscriber.
Therefore, depending on the setting of the "threshold" for regulating the usage rate of trunk groups, the probability that a high-priority call will be blocked increases, or vice versa. There are problems such as reducing line usage efficiency in an attempt to reduce high call blocking. Also, since the usage rate is obtained by calculating the average value for a certain time unit,
The responsiveness to load changes is also low, and when there are many levels of priority (for example, 3 or more), setting a "threshold" becomes very complicated and difficult.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a priority connection method that eliminates the drawbacks of the prior art described above, maintains line usage efficiency at a high level, and reliably connects high-priority calls.

[Summary of the invention]

In the priority connection system according to the present invention, when all trunks in the same trunk group of a telephone exchange are in use, when a higher priority call occurs and requires the use of the trunk, a lower priority call After searching the trunk being used by the trunk from its busy chain and sending a forced disconnection signal to that interoffice line, the above-mentioned high priority call is connected to the above-mentioned searched trunk. It is something to control.

This can be explained as follows.

First, when a call regarding the same trunk group is connected, the in-use chain (memory linkage) of the in-use trunk is determined according to the priority level of the call.
form. When a call with a high priority occurs while all of the trunk groups are busy, a trunk used by a call with a lower priority is found from the busy chain.

Next, the communication path of the subscriber connected to the trunk is forcibly disconnected, and a forcible disconnection signal is also sent to the other party using the trunk line signal. The destination station (terminating station) that receives the forced disconnection signal forcibly disconnects the communication path of the subscriber connected to the trunk that received the forced disconnection signal.

In order to avoid disconnecting the inter-office line at this time, the originating station performs an outgoing connection operation regarding the trunk (for example, connection with an outgoing connection sender), and the receiving station performs an incoming connection operation regarding the trunk (for example, connection with an outgoing connection sender). A new call with a high priority is connected by making a connection with an incoming connection register and sending and receiving a selection signal between them.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 2 to 4.

FIG. 2 is a relay system diagram of an embodiment of the priority connection system according to the present invention, FIG. 3 is a connection process diagram thereof, and FIG. 4 is an explanatory diagram of a busy chain of the same trunk.

Here, 1 is the originating exchange (station A), 2 is the terminating exchange (station B), and 3A, 3B, 4A, and 4B are the trunks (TRKA, TRKB,
TRKC, TRKD), 5A, 7 are high priority originating subscribers (k, x), 5B is low priority originating subscribers (l), 6A, 6B, 8 are terminating subscribers (m,
n, y).

FIG. 3 is a diagram in which the connection change in FIG. 2 is broken down according to changes in line signals, where BT is a busy tone trunk, OS is an outgoing connection sender, and IR is an incoming connection register.

FIG. 4 shows an embodiment in which a trunk busy chain is formed using the memory linkage of the trunk memory.

In Fig. 2, between the A station and the B station, each trunk TRKA=TRKC and each trunk TRKB-
It is connected by two TRKD lines.

First, subscriber h with a higher priority makes a call and is connected to subscriber m of station B via trunks TRKA and TRKC. In this connection, the trunk TRKA is
The high-priority call shown in FIG. 4 is registered in the busy chain HCHAIN of the trunk to which it is connected.

The chain of trunks in use indicates the linkage of the trunk memory, which is a trunk information storage memory provided for each trunk. There are three types of chains: a certain HCHAIN, a LCHAIN which is a chain of trunks used by low priority calls, and an idle chain which is a chain of empty trunks. The linkage of each chain will be explained using FIG. 4A. Note that the LCHAIN and the idle chain have exactly the same configuration, so a description thereof will be omitted. There is an address storage area for linkage at the top of the trunk memory (lower number memory), and the address #A2 of the trunk memory TRKA2 is stored in the trunk memory TRKA1.
Trunk memory In TRKA2, trunk memory
Address #A3 of TRK3 is stored, and "0" indicating that there is no next linkage is stored in trunk memory TRKA3.

In addition, the second area of the trunk memory stores an address indicating the previous trunk of the linkage, and in the trunk memory TRKA1,
“0” indicating the top position is stored in the trunk memory TRKA2.
In the trunk memory TRKA3, #A2, which is the address of the trunk memory TRKA2, is stored.

In addition, the first and last addresses of the trunk memory are set to the highest part HEAD of the address indicated by HCHAIN, and the first trunk memory TRKA
1 address #A1 is stored, and the last trunk memory TRKA3 is stored in the second area TAIL.
address #A3 is stored.

If you are newly registering for this chain,
Find the last trunk memory from the TAIL of HCHAIN, store the address of the trunk memory to be registered, store "0" at the top of the own trunk memory, store the previous trunk memory address at the second position, and then Store the address of the own trunk memory in the HAIL section of HCHAIN.

Furthermore, when the call ends, the addresses of the previous and subsequent trunk memories are determined from the highest address of the own trunk memory, and the contents are rewritten to remove them from the chain in use.

Next, subscriber l with a lower priority makes a call and is connected to subscriber n of station B via trunks TRKB and TRKD. In this connection, the trunk TRKB is registered with the busy chain LCHAIN of the trunk to which the lower priority call is connected. As a result of the above two calls, the lines between stations A and B are all in a busy state.

In this case, when subscriber x with a high priority makes a connection request to subscriber y of station B, station A gives priority to the trunk TRKB used by subscriber l with a lower priority than subscriber x. Find (search) from the in-use chain LCHAIN of the lower-ranked trunk. Trunk TRKB from this chain
According to the information, the communication path between the trunk TRKB and the subscriber 1 is forcibly disconnected, and a busy tone connection is established for the subscriber 1. Furthermore, a forced disconnection signal is sent to the trunk TRKD of the B station via the line signal line of the trunk TRKB.

At station B, when the forced disconnection signal is identified by the trunk TRKD line signal, the trunk
The communication path between TRKD and subscriber n is forcibly disconnected, and a busy tone connection is established for subscriber n.

When the communication paths of subscribers l and n connected to trunks TRKB and TRKD are disconnected, station A
The outgoing connection sender OS is connected to TRKB, and the incoming connection register IR is connected to the trunk TRKD at station B to send and receive selection signals, and then the subscriber x-trunk TRKB is connected by the normal connection procedure.
- Trunk TRKD - Connection of subscriber y is completed.

Finally, the forced disconnection signal will be explained in more detail using FIG. In this embodiment, an E&M continuous signal system is used as the line signal.

In Figure 3, SS and SR are line signal lines,
SS indicates the sending side, and SR indicates the receiving side. FIG. 3A shows a state in which subscriber 1 - trunk TRKB - trunk TRKD - subscriber n are talking, and both the SS and SR lines are in the ON (connected) state.

Next, in Figure B, the communication path between trunk TRKB and subscriber L is forcibly disconnected, and trunk TRKB
This shows a state in which a forced disconnection signal is sent from trunk TRKD to trunk TRKD.

Forcible disconnection signal is 300m along the SS line of trunk TRK.
When station B receives this OFF signal, it forcibly disconnects the communication path between trunk TRKD and subscriber n, as shown in c in the figure. A busy tone connection is connected to subscriber n, and an incoming connection register IR is connected to trunk TRKD. Also, after completing the connection of the incoming connection register IR, the trunk TRKD
Turn off the SS line and request station A to send a selection signal.

On the other hand, after sending the forced disconnection signal, station A connects the outgoing connection sender OS to the trunk TRKB, and waits for the selection signal to be sent to the trunk TRKB.
It monitors whether the SR line of the trunk TRKB becomes OFF, and starts sending a selection signal when the SR line of the trunk TRKB becomes OFF. The subsequent calling and response sequences are the same as for general connections, so their explanations will be omitted.

Although the above explanation has been made using the E&M continuous type signal system, other signal systems can be easily implemented by defining a forced disconnection signal.

In this way, according to this embodiment, all trunks for the same route are busy, and there are no restrictions on lower priority calls until a higher priority call is encountered while all trunks are busy. The line can be used without being overloaded, improving the efficiency of line usage.
Furthermore, if lines can be prepared to match the volume of high-priority calls, high-priority calls can be reliably connected without blocking.

〔Effect of the invention〕

As described above, according to the present invention, high priority calls can be reliably connected, and regardless of the line usage rate, low priority calls can be connected as long as the line is free. Since it is also possible to connect to the telephone exchange, a remarkable effect can be obtained in improving the efficiency of line usage in the telephone exchange and improving the serviceability.

[Brief explanation of the drawing]

FIG. 1 is a relay system diagram for explaining a conventional priority connection system, FIG. 2 is a relay system diagram of an embodiment of the priority connection system according to the present invention, and FIG. 3 is a connection process diagram thereof. FIG. 4 is an explanatory diagram of the in-use chain of the same trunk. 1... Originating side exchange, 2... Incoming side exchange, 3
A, 3B, 4A, 4B... Trunk, 5A, 5
B, 7... Originating subscriber, 6A, 6B, 8... Incoming subscriber.

Claims (1)

[Claims] 1. The priority order of calls accommodated in each trunk connecting between telephone exchanges is stored in advance, and when all trunks in the same trunk group of telephone exchanges are in use, When a call occurs and requires the use of the above-mentioned trunk, by referring to the above-mentioned stored priorities, a trunk accommodating a call with a lower priority than the priority of the higher-priority call is selected. A priority connection method characterized in that, after searching, and sending a forced disconnection signal to the interoffice line, control is performed so that the high priority call is newly connected to the searched trunk. 2. In what is stated in claim 1,
The telephone exchange on the originating side performs an outgoing connection operation, and the telephone exchange on the receiving side performs an incoming connection operation for the above-mentioned high-priority call without disconnecting the interoffice line to which the forced disconnection signal was sent. Priority connection method. 3 In what is stated in claim 1,
The priority order of the calls accommodated in each trunk is stored in the trunk memory of each trunk, including the addresses of the trunks that accommodate calls with the priority order that is higher and lower than the priority order of calls accommodated by the own trunk. A priority connection method that performs this by storing data and forming memory linkages.