JPH0516720B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a trunk selection method in a private telephone exchange equipped with a so-called direct inline function, and in particular, when making a call to a central office line, general dialing operations are performed from an extension telephone. The present invention relates to a trunk selection system in a private branch telephone exchange in which, when a special operation is performed prior to the extension, a central office trunk that has a correspondence relationship with the extension telephone is selected.

[Background of the invention]

In a private branch exchange, when a call is received on a central office line trunk, the so-called direct in-line method is known as a method in which the call is directly delivered to an extension telephone without passing through a relay stand. In the direct inline system, incoming calls to a central office line trunk are received directly to an extension telephone that has a correspondence relationship with the central office trunk, but if necessary, the incoming call can be transferred to another telephone extension using a forwarding function, etc. Transfer connections are also allowed. In addition, when a call is made from an extension telephone to a central office line, the correspondence relationship between the central office line and the extension telephone related to the direct inline function is canceled, and when a general dialing operation is performed from the extension telephone, In this system, any one vacant office line trunk is directly selected from among a plurality of office line trunks without passing through a relay stand, and then a call is made to the office line.

By the way, if we assume that a telegram transmission call, etc. is made from a certain extension telephone to a telephone office via a private telephone exchange, the calling extension subscriber will be able to send the selected telephone number to the telephone office. It has become necessary to notify. This is because after the call ends, the calling extension subscriber must be called back by the central office via the private branch exchange to confirm the billing destination, etc.

Now, a problem with such telegram transmission calls is that the originating extension subscriber generally cannot know the central office line number selected at that time. In order to know the station line number, some sort of station line number display device is required. For example, the well-known distributed response function (when an incoming call is received from a central office line, a large incoming call display panel installed on the ceiling etc. displays this fact, and after visually confirming the incoming call display, a predetermined special call is sent from the extension telephone). It was necessary to adopt a method such as displaying the central office line number on the incoming call display panel (a function that connects a line by dialing a number). In addition to these problems, even if the central office line number obtained through some method is notified to the central office, calls returned from the central office will be returned within the premises using the direct inline method based on the central office line number. Since a call is received at a telephone exchange and is directly connected to the telephone extension that corresponds to the central office line number, the probability that the incoming call will be directly connected to the calling extension subscriber is generally small, and in many cases, the central office line number The call will be forwarded from the extension phone that corresponds to the call, and you will need to confirm the billing address, etc.

[Purpose of the invention]

An object of the present invention is to provide a private branch telephone exchange equipped with a direct inline function.
When a call back is later made via the central line number for an extension telephone that made a call to a central office line, the calling extension subscriber does not need to confirm the central telephone number for the call back on some display device. To provide a trunk selection system in a private branch telephone exchange, which is easily known as a private branch telephone exchange, and in which incoming calls for callbacks are directly terminated at the extension telephone.

[Summary of the invention]

To achieve the above purpose, the present invention provides a method for making a call to a central office line using a special operation from the calling extension telephone when the calling extension subscriber needs to know the central office line number. This allows calls to be made to the central office line while the correspondence between the telephone line and the extension telephone is restored. Since the originating extension subscriber already knows the office line number (or office line trunk) that corresponds to his/her own extension telephone, it is unnecessary to display the office line number and the office line number for callback is not required. It is possible to immediately and easily notify the other party, and based on the central office line number, the other party can directly receive a return call to the originating extension telephone using the direct in-line method.

In addition, when making a call to a central office line as described above, when the central office line trunk that corresponds to the extension telephone is selected, the degree of freedom in selecting the central office trunk is small to begin with, and moreover, the central office line trunk is Since there is a possibility that the call has already been captured by a call made to the central office line by a general dialing operation from another extension telephone, the failure rate in selecting the central office line trunk is considered to be relatively high. However, the frequency of cases in which central office line trunks are selected in the manner described above is extremely small compared to cases in which central office line trunks are generally selected, and therefore it is considered to be of little concern in terms of service. Conceivable. Rather, the effect of the defect is more important than the defect.

[Embodiments of the invention]

The present invention will be explained below with reference to FIGS. 1 to 3.

First, the private branch telephone exchange according to the present invention will be described. FIG. 1 shows the system configuration of an example of the private branch telephone exchange according to the present invention, which is equipped with a direct inline function. As shown in the figure, a private branch telephone exchange 1 accommodates a plurality of office line trunks 2 and extension telephones 3, and an extension correspondence memory 4 provided for a calling telephone 3 is stored in the private branch telephone exchange 1. When a stored program control system is adopted, this corresponds to a subscriber memory provided as a part of the main memory within the private branch exchange 1. The extension telephone 3 is stored in the memory 4 corresponding to the extension.
The central office trunk number (or the extension telephone 3 that corresponds to the central office trunk number) is stored in advance. Therefore,
When a call is received on any of the central office trunks 2, the extension correspondence memory 4 is searched based on the central office trunk number, so that the extension telephone 3 corresponding to the central office trunk is known. In addition, a direct in-line service can be provided in which the incoming call is directly received by the extension telephone 3.

On the other hand, when an extension subscriber makes a general dialing operation from the extension telephone 3 when making a call to the central office line, one of the multiple central office line trunks (four in this example) 2 can be dialed without going through the relay stand. From there, any one of the vacant central office line trunks is directly selected, and then a call is made to the central office line. The method for selecting such a central office line trunk is the same as the previous one. However, when making a call to a central office line, if a special operation is performed from the extension telephone 3 prior to the general dialing operation, an extension indicating the correspondence relationship between the extension telephone 3 and the central office trunk 2 related to the direct inline function may be used. By referring to the correspondence memory 4, the central office line trunk 2 corresponding to the extension telephone 3 can be uniquely selected. Since the extension subscriber is notified in advance of the central office line trunk number that has a unique correspondence with his/her own extension telephone 3, and therefore the central office line number, the number is sufficiently known. Therefore, it is possible to notify the other party of the central office line number without hesitation.

FIG. 2 also shows an exchange processing algorithm when a dialing operation is performed on the extension telephone 3 housed in the private branch telephone exchange 1. Of course, this switching processing algorithm can be realized only by software if the private branch telephone exchange 1 employs a stored program control system. Now, to explain the algorithm, first, in step S1, operation dial digits from the extension telephone 3 are received, and in step S2, the received dial digits are discriminated. In Step 2, it is determined whether or not a special code exists before the general dialed number. If a special code exists, in Step S4, the extension corresponding to that extension telephone is determined. The central office line number stored in the memory 4 is read out, and the designated central office line trunk that has a unique correspondence with the extension telephone 3 is selected. If no special code exists, a vacant office line trunk is generally selected in step S3. After the central office line trunk is selected in step S3 or step S4, the central office line connection operation is executed for the first time in step S5. In addition,
If the selection of a central office line trunk fails in step S4, a busy tone is sent to the extension telephone 3. In addition, if the first central office line trunk selection fails in step S3, the central office line trunk selection process is repeated sequentially with the vacant central office line trunks being selected; A busy tone is first sent to the extension telephone 3 when the extension telephone 3 is not in that state.

FIG. 3 also shows an example of the central office line trunk selection processing operation. In this case, the pointer 5 indicates a vacant office line trunk 6, and the office line trunk 6 indicated by the pointer 5 has
The vacant office line trunks are connected again, and thereafter, the vacant central office line trunks 7 and 7 are connected again.
8 are connected in a chain. Therefore, the central office line trunk that has been transferred from the captured state to the free state is the one connected to the tail end of such a trunk chain.

Now, when making a call to a central office line, if no special operation is performed from the extension telephone and an empty central office line trunk is generally selected, it is possible to select one after another from the beginning of the trunk chain. It's good. In this example, the office line trunk 6 is selected first, and then the office line trunks 7 and 8 are selected in sequence. In addition, when making a call to a central office line, if a special operation is performed from an extension telephone and the central telephone trunk corresponding to the extension telephone is selected by referring to the extension correspondence memory, the trunk chain is sequentially selected. As if hanging around,
After searching for the designated trunk, processing is performed to extract it from the middle of the trunk chain.By performing this process, even if a special code is dialed, the designated station line trunk can be easily selected. .

In the above example, the central office line trunk of the specified central office line number is selected by dialing a special code, but this is not limiting. By operating the special pushbuttons provided,
The central office line trunk of the designated central office line number may be selected. Furthermore, although it is explained that central office line trunks with different central office line numbers are uniquely assigned to correspond to telephone extensions, the same central telephone number can be assigned to multiple telephone extensions within the same group, but this is not limited to this. Alternatively, the central office line trunk may be selected.

〔Effect of the invention〕

As described above, according to the present invention, when a callback is later made via the central telephone line to an extension telephone that made a call to the central telephone line, the calling extension subscriber can use the central telephone line for the call back. It is easy to know the number without having to check it on any display device, and incoming calls for callbacks can be received directly to the extension telephone.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a system configuration of an example of a private branch telephone exchange according to the present invention, which is equipped with a direct inline function, and FIG. 2 is a diagram showing a dial operation using an extension telephone housed in the private branch telephone exchange. FIG. 3 is a diagram illustrating an example of the switching processing algorithm in the case where the exchange processing is performed. 1...Private telephone exchange, 2, 5, 6, 7, 8...
... central office trunk, 3 ... extension telephone, 4 ... extension correspondence memory, 5 ... pointer.

Claims (1)

[Claims] 1. A trunk selection method in a private telephone exchange equipped with a so-called direct in-line function, which allows incoming calls from a central office line to be directly connected to an extension telephone set that corresponds to the central office line in advance, without passing through a relay stand. Therefore, when a call is made from an extension telephone targeted for direct inline to a central office line, if a special operation is performed prior to the general dialing operation, the correspondence relationship between the extension telephone and the above correspondence is established without going through the relay stand. If a central office line trunk is selected and a call is made to the central office line, but only general dialing is performed without performing any of the above special operations, the above correspondence between the central office line and the extension telephone will occur. In a state where the relationship is canceled, any one vacant central office line trunk is selected from among the multiple central office line trunks without passing through the relay stand, and the call is made to the central office line. trunk selection method in a private branch telephone exchange.