KR970002754B1 - Control method for pbx - Google Patents

Abstract

A main processer(14) of which the received digit is converted detects if an user is in the suspended status, using a digit conversion table. The detection reveals that the receiver is in the suspense status, the main processer(14) sends a massages with a signal treatment processer(18), asking to ring the bell. On the other hand if the ringed inward line user is off-hook, this can be detected by the signal treatment processer(18), and is transferred to the main processer(14). In this juncture, the main processer(14) decides that the receiver is in off hook and gives a signal by connecting it thru the DID line user.

Description

Extension Direct Call Control Method in Private Switching System

1 is a DID trunk line connection state diagram for explaining a conventional DID control method;

2 is a block diagram of a private exchange system for carrying out the present invention;

3 is a flowchart of a method for direct extension call control of a private exchange system according to the present invention, showing a first embodiment;

4 is a flowchart of a method for direct extension call control of a private switching system according to the present invention, showing a second embodiment.

* Explanation of symbols for main parts of the drawings

12 RAM 14 Main Processor

16: ROM 18: Signal Processing Processor

30: key phone subscriber matching unit 22: CO line subscriber matching unit

24: time switch 26: regular telephone subscriber matching unit

28: tone transceiver

The present invention relates to a direct inward dialing (DID) control method of a private switching system, and in particular, when an external subscriber calls a specific extension when receiving a DID, the call can be connected even when the corresponding subscriber is busy. The present invention relates to a DID call control method for controlling an extension call by supplementing it internally even if an internal number is insufficiently transmitted by a DID trunk line.

In general, DID refers to a calling method in which a private exchange that uses a plurality of trunk lines in an extension telephone line call directly calls an extension subscriber using only a signal from the trunk line so that a call can be made with an external subscriber, for example, a subscriber of the trunk line. . Such a DID is widely used in a private exchange that accommodates many trunk lines. In order to service such a DID, unlike a general CO line subscriber line, a DID CO line of a general officer exchange must be cited. The DID trunk line is configured to send out the extension subscriber number of the private exchange to call the extension subscriber of the private exchange when an external subscriber (national subscriber) dials in the DID trunk line number.

The DID trunk line of the CO is connected to a private exchange as shown in FIG. 1, and the private exchange has a number of extension subscribers that can talk to internal subscribers and can also talk to a CO subscriber. have. Here, the extension subscriber includes both a key phone subscriber or a general telephone subscriber who receives a special service.

First, a conventional operation will be described with reference to FIG. 1.

When the external subscriber dials 1234 to the X45 station to call the extension subscriber of the private exchange accepting and using the DID trunk line, it is sent to the local exchange. Here, "1234" of the number X45-1234 is the extension number of the extension subscriber connected to the private exchange.

When the external subscriber dials X45-1234, the local exchange transmits "1234" which recognizes the extension number to the DID trunk line connected to the private exchange in response to the input of the telephone number. The private exchange recognizes the "1234" number coming after the incoming call and raises the incoming call ring to the extension subscriber "1234". When the subscriber picks up the receiver, the private exchange makes a call between the external subscriber and the extension subscriber. .

However, the conventional method of serving a DlD call using only the DID trunk line as described above has the following problems.

(1) If the number of digits, the telephone number of the extension subscriber transmitted by the DID trunk line, does not match the number of digits of the extension subscribers actually used by the private exchange, the service will not be provided. For example, in the private exchange, the telephone number of the extension subscriber is used as three digits. However, when a four digit telephone number is transmitted from the DID trunk line, there is a problem in that the call service is not made and the error is processed.

(2) In case that the extension subscriber is busy, the "1234" dialed by the CO subscriber must ring only the extension subscriber "1234" of the private exchange, and the extension subscriber is busy even though the non-extension phone of the adjacent location is free. There was no call service.

Accordingly, an object of the present invention is to provide a DID call control method for detecting an extension call from an external dialer so that the extension subscriber can receive an external call.

Another object of the present invention is to provide a DID call control method for executing a call service by compensating for a phone number of an extension subscriber transmitted from a DID trunk line and a phone number used by extension subscribers of a private exchange.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a private switching system for carrying out the present invention, comprising: a main processor processor 14 for controlling all of the user's service provision by controlling the call processing service of the private switching center, basic call trunk and various functions. RAM 12, which temporarily stores processing data for a service, a program according to the present invention, and a ROM which stores an exchange service processing program and outputs it by the main processing processor 14; And a signal processing processor 18 for controlling various devices depending on the private exchange, and located at the positions of the main processor 14 and the signal processing processor l8. FIFO (Common MemoIy) 20, which forms a data path, and interfacing with the system, such as supplying a call band in response band to a telephone of a general extension subscriber. Under the control of the general telephone subscriber matching unit 30 and the signal processing processor 18, the CO line is seized to form a CO line loop, and the CO line subscriber matching interface to the incoming signal from the CO line. The unit 22, a time switch (TSW) 24 for switching various tones and voice data under the control of the signal processing processor 18, and a key phone subscriber interface for interfacing with a key phone telephone. And a communication transceiver 28 for receiving digits from the trunk line received through the TSW 24.

3 is a flowchart of a method for direct extension call control of a private switching system according to the present invention, showing a first embodiment.

4 is a flowchart of a method for controlling an extension direct call in a private exchange system according to the present invention, showing a second embodiment.

Programs such as 3rd and 4th should be masked in the area of the ROM 16 of FIG.

The operation of the first embodiment according to the present invention is described below with reference to the second and third drawings.

The signal processing processor 18 shown in FIG. 2 scans the trunk subscriber registration unit 22 at predetermined intervals to search for incoming calls. When the incoming line is detected by the scanning operation as described above, the signal processor 18 transmits the incoming call to the main processor 14 through the packet 20.

The main process 14 checks whether the trunk line is a DID trunk line (Step 3 in FIG. 32). If it is confirmed that the trunk line is a DID trunk line, the main process 14 captures a related message to allow the signal processing processor to perform relay line control (Relay Contro1). 20) (36 process in FIG. 3). At this time, the signal processing processor 18 connects the DTMF receiver in the tone transmitting and receiving device 28 and the trunk line subscriber matching unit 22 through the TSW 24 in response to the input of the communication message.

The signal processor 18 then searches for whether a digit is received via the DID trunk line (steps 38 and 40 in FIG. 3). When the search result digit is received, the signal processing processor 18 transmits the received digit to the host processor 14, and the host device 14 confirms whether the digit has been received (process 44 in FIG. 3). ).

The digit is not received until the timeout set in the above search process is exceeded (process 40 in FIG. 3), and the main processor processor l4 transmits a message to the signal processing processor 18 to disconnect the trunk line. Cut off the CO line (step 42 in Fig. 3).

If the time is out of time, it continues to wait for the next digit from the signal processing process (l8).

On the other hand, if the host processor 14 determines that the extension number has been received by the above operation (step 44 in FIG. 3), the received digit is converted (step 46 in FIG. 3). In this case, the completion of digit reception may be determined by searching whether a minimum number of digits is input. For example, it may be determined by searching whether at least two digits have been received, and it is possible to search whether the digit for the extension number call has been received by comparing the digits of the digits previously set with the digits of the received digits. The conversion of the received digits is converted based on the digit conversion table shown in Table 1 below, in order to find a subscriber to ring an incoming ring. At this time, the digit conversion table is stored in the storage area of the RAM 12 of FIG.

Table (1)

Digit Conversion Table

That is, the host processor 14 may use the digit conversion table as shown in Table 1 to send an incoming call to any other extension subscriber or extension group regardless of the input digit. For example, if a 4-digit digit is sent from a DID trunk line (if the private exchange uses a three-digit extension), it can be converted to a digit for the private exchange (casel in Table 1). If a new digit extension number is used and only two digits are entered through the CO line, it can be automatically converted to a three digit digit for the private exchange (Case2 in Table 1). Such conversion of digits can be performed by inputting the recipient subscriber's number having the lower two digits or the new digit of the received digit as the called number in a region addressed to the lower two digits or the new digit of the received digit. .

The main process 14 converting the received digits in the above process searches for the IDLE status determined using the digit conversion table (step 48 in FIG. 3). When the called subscriber is in the dormant state, the host processor 14 transmits a message to the signal processing process 18 so as to ring the called subscriber (step 50 in FIG. 3). At this time, the signal processing processor 18 sends a ring to the corresponding subscriber in response to receiving the message.

If the station subscriber who has sent the ring is off-hook, the fact is detected by the signal processing process 18 and transmitted to the main process 14. At this time, the main device process 14 determines that the corresponding subscriber is off-hook, and transmits a message to the signal processing process 18 so that the corresponding subscriber is connected to the trunk line of the trunk line subscriber and the call is made (process 54 in FIG. 3). .

If the incoming subscriber is busy in the search process described above, the busy tone is sent to terminate the service.

By the above operation, even if the DID trunk line transmits an insufficient number of digits, the system internally compensates for this and controls an extension call.

Referring to FIG. 4, the operation of the second embodiment for connecting a DID incoming call to a busy subscriber is as follows.

After the incoming call, the process of receiving the digit from the CO line and converting the digit is the same as the operation of step 46 of FIG. 3. Here, if it is determined that the subscriber is busy (step 48 of FIG. 4) at the time of ringing the called subscriber obtained by digit conversion, the main processor 14 reads the extended digit conversion table as shown in Table 2 below. Determine the state of the Call wait option.

Table (1-2)

Extended Digit Conversion Table

If the CW option during a call is set to "Y" (fixed at 58 in Fig. 4), the host process 14 sends an off hook tone message to the signal processing process l8. Have the busy participant hear the off-hook tone (step 62 in FIG. 4).

In the above state, if the signal processing process 18 determines that the user has pressed the Call Wait (CW) button for the state of the subscriber who was on the call (step 64 in FIG. 4), the signal processing process 18 acknowledges this fact. Send it as a message to (14). At this time, the main unit process 14 temporarily suspends the current call and transmits a message to the signal processing process 14 to connect the incoming CO line subscriber to the call processing process so that the signal processing process 14 receives the call and connects the call. Processing (68 in FIG. 4).

By the above operation, even if a DID call for calling an extension subscriber occurs in a state where the extension subscriber is in a call, it can be seen that a call path between an external subscriber and a feature extension subscriber can be connected.

As described above, the present invention can receive a DID incoming call to any extension subscriber / extension group regardless of the extension number input through the DID trunk line, and transmits the number of digits used in the private exchange and the DID trunk line. Even if the number of digits has been different, DID incoming service can be performed smoothly, and DID call arrival and reception signal can be connected to the extension subscriber who is busy.

Claims (4)

A direct telephone call control method of a private switching system connected to a DID trunk line of a local exchange, comprising: a digit receiving process of receiving a digit for an extension subscriber call transmitted from the DID trunk line in response to an incoming call of a DID trunk line; Is a call number of an extension subscriber, and an incoming call transmission process of transmitting an incoming call to an extension subscriber corresponding to the converted digit; and when the corresponding extension subscriber responds to the incoming call, a trunk line subscription of a called subscriber and a DID is received. An extension direct call control method of a private exchange system, characterized in that the process of forming a communication path to form a communication path between. 2. The private exchange system of claim 1, wherein the digit receiving process further comprises a step of searching whether a digit for calling an extension number is received by comparing a digit of a preset digit with a digit of a received digit. How to control an extension direct call. 3. The method of claim 2, wherein the incoming call transmission process comprises: converting a digit from a table in which a called party digit preset in a predetermined storage area is stored, and a digit number of the called party corresponding to the received digit number is stored; And an incoming call sending step of sending an incoming call to an extension subscriber corresponding to the converted digit. An extension direct call control method of a private switching system connected to a DID trunk line of a national exchange, comprising: a call receiving a digit for an extension subscriber call transmitted from the DID trunk line in response to an incoming call of a DID trunk line to retrieve a state of the called party; The subscriber call status search process, a subscriber class status search query for searching whether the called party is a callable subscriber in response to the called party being busy, and determining that the called party is a callable subscriber Characterized in that it comprises a call-route process for transmitting an off-hook tone, holding a counterpart subscriber in a call in response to an input of a call waiting message, and connecting the DID incoming call path to the called subscriber to form a call path. Extension Direct Call Control Method of Private Switching System.