Internal telephone system, main unit, program, and call forwarding method

Abstract

To provide an incoming call redirection technique which enables a quicker response without making a caller wait for a long time.SOLUTION: When terminating a call with a caller of a call to an extension terminal 2, a main device 1 updates a call management table associated with the extension terminal 2 and increments the number of calls of an on-hook call terminal. When the call management table 140 is updated, if an on-hook call terminal for a call management record 141 having the highest number of calls in the call management table 140 is the extension terminal 2 associated with the call management table 140, the main device does not set automatic call redirection to the extension terminal 2. If the on-hook call terminal is not the extension terminal 2, the main device sets automatic call redirection to the extension terminal 2 so as to automatically redirect a call to the on-hook call terminal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an internal telephone system, and more particularly to a call incoming transfer technology for an internal terminal as a destination.

Background Art

[0002] In Patent Document 1, in an internal telephone system, when a call incoming to an internal terminal (referred to as a first internal terminal) specified by a special number dialing is not answered by the first internal terminal and another internal terminal (referred to as a second internal terminal) answers on behalf, a technique is disclosed in which this second internal terminal is automatically set as the transfer destination of the call incoming to the first internal terminal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, although the call incoming to the first internal terminal is transferred to the second internal terminal, when the user of the second internal terminal is absent and cannot answer this call, even if another internal terminal (referred to as a third internal terminal) answers on behalf of the call transferred to the second internal terminal, the new call incoming to the first internal terminal is transferred not to the third internal terminal but to the second internal terminal where the user is absent, which is a problem. This may cause the caller to wait for a long time.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a call incoming transfer technology that can respond more quickly without making the caller wait for a long time.

Means for Solving the Problems

[0006] To solve the above problems, in the present invention, when a call destined for any extension terminal is received, the main unit sends the call to the forwarding destination if automatic call forwarding is set for the call destination, and sends the call to the call destination if automatic call forwarding is not set for the call destination. The main unit then monitors the conversation with the caller, identifies the person the caller spoke with at the end of the conversation, and increments the call count of that person registered in the call management table associated with the call destination by 1. If the call count of the person is not registered in the call management table, the call count of "1" is registered in this call management table. At times such as when the call management table is updated, the main unit sets automatic call forwarding to the extension terminal associated with the call management table, designating the extension terminal with the most calls in the call management table as the forwarding destination. Here, if the extension terminal with the most calls is the extension terminal associated with this call management table itself, automatic call forwarding is not set for this extension terminal, or the automatic call forwarding setting is canceled.

[0007] For example, the present invention is An extension telephone system comprising a plurality of extension terminals and a main unit that accommodates the plurality of extension terminals, The main device is, For each of the aforementioned extension terminals, the person the caller of a call destined for that extension terminal is talking to at the end of the call is The person on the other end of the call Number of calls and the last call date and time with the caller. A call management table storage means that stores a call management table linked to and stored by, When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding is sent to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means is provided to identify the caller at the end of the call, When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. The system includes an automatic call forwarding setting means that, if the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, does not set up automatic call forwarding for the extension terminal linked to the call management table, and if the extension terminal with the most calls is not the extension terminal linked to the call management table, it sets up automatic call forwarding for the extension terminal linked to the call management table, with the extension terminal with the most calls as the call forwarding destination. death, The aforementioned call management table update means is: When a call destined for the aforementioned extension terminal is received and the call recipient is identified by the call monitoring means, the call management table stored in the call management table storage means, which is linked to the said extension terminal, is updated to increment the call count of the said call recipient by one, and the last call date and time of the said call recipient is updated. The aforementioned automatic call forwarding setting means is If there are multiple extension terminals with the most calls in the call management table, the extension terminal with the most calls and the most recent last call date and time is identified from among them. If the extension terminal with the most calls and the most recent last call date and time is the extension terminal linked to the call management table, automatic call forwarding is not set for the extension terminal linked to the call management table. If the extension terminal with the most calls and the most recent last call date and time is not the extension terminal linked to the call management table, automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls and the most recent last call date and time as the call forwarding destination. . [Effects of the Invention]

[0008] According to the present invention, the terminal used to end a call with an extension terminal is managed in a call management table linked to the extension terminal of the call destination. In the call management table, if the extension terminal with the most calls as the terminal used to end a call is the extension terminal of the call destination, automatic call forwarding is not set for the call destination. On the other hand, if the extension terminal with the most calls as the terminal used to end a call is not the extension terminal of the call destination, automatic call forwarding is set for the call destination to this extension terminal with the most calls. As a result, calls can be sent to extension terminals that frequently communicate with the caller, that is, to extension terminals of users that are highly likely to be able to effectively respond to the caller of a call with an extension terminal as the destination. Therefore, incoming calls with an extension terminal as the destination can be answered more quickly without making the caller wait for a long time. [Brief explanation of the drawing]

[0009] [Figure 1]FIG. 1 is a schematic configuration diagram of an internal telephone system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a sequence diagram for explaining an operation example of an outside line incoming call process of an internal telephone system according to an embodiment of the present invention. [Figure 3] FIG. 3 is a sequence diagram for explaining an operation example of an outside line incoming call process of an internal telephone system according to an embodiment of the present invention, and is a continuation of FIG. 2. [Figure 4] FIG. 4 is a sequence diagram for explaining an operation example of an outside line incoming call process of an internal telephone system according to an embodiment of the present invention, and is a continuation of FIG. 3. [Figure 5] FIG. 5 is a schematic functional configuration diagram of the main device 1. [Figure 6] FIG. 6 is a diagram schematically showing an example of registered contents in the call management table storage unit 14. [Figure 7] FIG. 7 is a flowchart for explaining an incoming call process of the main device 1. [Figure 8] FIG. 8 is a flowchart for explaining an automatic incoming call transfer setting process of the main device 1. [Figure 9] FIG. 9 is a flowchart for explaining a call management table initialization process of the main device 1.

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a schematic configuration diagram of an internal telephone system according to the present embodiment.

[0012] As shown in the figure, the in-house telephone system according to the present embodiment includes a main device 1 connected to an external telephone network 4 such as an IP (Internet Protocol) telephone network or a PSTN (Public Switched Telephone Network) to which an external terminal 3 is connected, and an in-house telephone network 5 composed of a LAN (Local Area Network), an analog line, etc., and a plurality of in-house terminals 2-1 to 2-n (hereinafter also simply referred to as in-house terminal 2) accommodated in the main device 1 via the in-house telephone network 5.

[0013] The main device 1 cooperates with the in-house terminal 2 to establish a call path between the in-house terminal 2 and the external terminal 3 or between the in-house terminals 2, and relays the call between the in-house terminal 2 and the external terminal 3 or the call between the in-house terminals 2 via this call path. Further, when a call destined for any in-house terminal 2 arrives, if automatic call transfer is set for the in-house terminal 2 that is the destination of the incoming call, the main device 1 sends the incoming call to the call transfer destination, and if automatic call transfer is not set for the in-house terminal 2 that is the destination of the incoming call, the main device 1 sends the incoming call to the in-house terminal 2 at that destination. Furthermore, the main device 1 monitors the call between the caller of the incoming call and the in-house terminal 2 that is the call partner, identifies the call partner (referred to as the end-of-call terminal) at the end of the call, and increments by one the call count of the end-of-call terminal registered in the call management table associated with the call destination. Also, when the call management table is updated, the main device 1 sets automatic call transfer for the in-house terminal 2 associated with this call management table with the in-house terminal 2 having the most call counts as the call transfer destination. If the in-house terminal 2 having the most call counts is the in-house terminal 2 itself associated with this call management table, automatic call transfer is not set.

[0014] FIGS. 2 to 4 are sequence diagrams for explaining an operation example of the external call incoming process of the in-house telephone system according to the present embodiment.

[0015] Here, it is assumed that the call management table stored in the main device 1 associated with the in-house terminal 2-3 is initialized, and the main device 1 has not set automatic call transfer for the in-house terminal 2-3.

[0016] Assume that a call has arrived at the main unit 1 from an external terminal 3 via the external telephone network 4, destined for extension terminals 2-3, which are identified by a special dial number (S100). In response, the main unit 1 confirms that automatic call forwarding is not set up for extension terminal 2-3 (S101), and sends the incoming call to extension terminal 2-3 along with the designation of ringtone 1 (normal ringtone) (S102).

[0017] When an extension terminal 2-3 receives a call from the main unit 1, it rings with the ringtone 1 specified for the incoming call (S103). Then, when extension terminal 2-3 receives an answer operation from the user (S104), it sends a response back to the main unit 1 (S105). In response, the main unit 1 sends a response back to the external terminal 3 via the external telephone network 4 (S106). As a result, a call path is established between the main unit 1 and extension terminal 2-3, and between the main unit 1 and the external terminal 3, and the main unit 1 relays these call paths (S107). This enables communication between extension terminal 2-3 and external terminal 3.

[0018] Subsequently, when the main unit 1 processes the termination of the call between extension terminal 2-3 and external terminal 3 (S108) and releases the call path to them, it identifies extension terminal 2-3 as the terminal that terminated the call (S109). Then, the main unit 1 updates the call management table associated with extension terminal 2-3, which is the destination of the incoming call, and registers "1" in this call management table, which is the number of times extension terminal 2-3 has made a call as the terminal that terminated the call (S110).

[0019] Next, when the call management table is updated, the main unit 1 identifies the extension terminal 2 with the highest number of calls as the final call terminal among the extension terminals 2 registered in this call management table, and based on this identification result, it determines whether or not to set up automatic call forwarding for extension terminals 2-3 linked to this call management table. Here, extension terminal 2-3 (number of calls "1") is identified as the extension terminal 2 with the highest number of calls as the final call terminal. Since the identified extension terminal 2-3 is the extension terminal 2 linked to this call management table, the main unit 1 does not set up automatic call forwarding for this extension terminal 2-3 (S111).

[0020] Subsequently, it is assumed that a call destined for extension terminals 2-3, identified by a special dial number, has been received by the main unit 1 from the external terminal 3 via the external telephone network 4 (S112). In response, the main unit 1 confirms that automatic call forwarding is not set up for extension terminal 2-3 (S113), and sends the incoming call to extension terminal 2-3 along with the designation of ringing tone 1 (normal ringing tone) (S114).

[0021] When an extension terminal 2-3 receives a call from the main unit 1, it rings with the ringtone 1 specified for the incoming call (S115). If extension terminal 2-3 does not receive a response operation from the user, but another extension terminal 2-2 receives a proxy response operation from the user (S116), extension terminal 2-2 sends a proxy response to the main unit 1 (S117). In response, the main unit 1 sends a response back to the external terminal 3 via the external telephone network 4 (S118). As a result, a call path is established between the main unit 1 and the proxy responder extension terminal 2-2, and between the main unit 1 and the external terminal 3, and the main unit 1 relays these call paths (S119). This enables communication between extension terminal 2-2 and the external terminal 3.

[0022] Subsequently, when the main unit 1 processes the termination of the call between extension terminal 2-2 and external terminal 3 (S120) and releases the call path to them, it identifies extension terminal 2-2 as the terminal that terminated the call (S121). Then, the main unit 1 updates the call management table associated with extension terminal 2-3, which is the destination of the incoming call, and registers "1" in this call management table, which is the number of times extension terminal 2-2 has made a call as the terminal that terminated the call (S122).

[0023] Next, when the call management table is updated, the main unit 1 identifies the extension terminal 2 with the highest number of calls as the last calling terminal among the extension terminals 2 registered in the call management table, and based on this identification result, it determines whether or not to set up automatic call forwarding for extension terminals 2-3 linked to this call management table. In this case, two extension terminals 2-2 and 2-3 (each with a call count of "1") are identified as extension terminals 2 with the highest number of calls as the last calling terminal. If multiple extension terminals 2 are identified, the main unit 1 further identifies the extension terminal with the most recent last call date and time (in this case, extension terminal 2-2). Since extension terminal 2-2 is not extension terminal 2-3 linked to the call management table, the main unit 1 sets up automatic call forwarding to extension terminal 2-3 linked to the call management table, with extension terminal 2-2 as the call forwarding destination (S123). Then, the main unit 1 sends call forwarding information, including information about the call forwarding destination (extension terminal 2-2), to extension terminal 2-3, which is set to automatically forward calls (S124), and extension terminal 2-3 displays the call forwarding information received from the main unit 1 (S125).

[0024] Subsequently, it is assumed that a call destined for extension terminal 2-3, which is identified by a special dial number, has been received by the main unit 1 from the external line terminal 3 via the external telephone network 4 (S126). In response, the main unit 1 confirms that automatic call forwarding is set up for extension terminal 2-3 (S127), and sends the received call to extension terminal 2-2, which is set as the call forwarding destination, along with specifying the ringing tone 2 (ringing tone for call forwarding). At the same time, destination information regarding the call's destination (extension terminal 2-3) is sent to extension terminal 2-2 (S128).

[0025] When an extension terminal 2-2 receives a call from the main unit 1, it rings with the ringtone 2 specified for the incoming call and displays the destination information (extension terminal 2-3) received from the main unit 1 (S129). If extension terminal 2-2 does not receive a response operation from the user, but another extension terminal 2-1 receives a proxy response operation from the user (S130), extension terminal 2-1 sends a proxy response to the main unit 1 (S131). In response, the main unit 1 sends a response back to the external terminal 3 via the external telephone network 4 (S132). As a result, a call path is established between the main unit 1 and the proxy responder extension terminal 2-1, and between the main unit 1 and the external terminal 3, and the main unit 1 relays these call paths (S133). This enables communication between extension terminal 2-1 and the external terminal 3.

[0026] Subsequently, when the main unit 1 processes the termination of the call between extension terminal 2-1 and external terminal 3 (S132) and releases the call path to them, it identifies extension terminal 2-1 as the terminal that made the call at the time of termination (S133). Then, the main unit 1 updates the call management table associated with extension terminal 2-3, which is the destination of the incoming call, and registers "1" as the number of times extension terminal 2-1 made a call as the terminal that made the call at the time of termination (S134).

[0027] Next, when the call management table is updated, the main unit 1 identifies the extension terminal 2 with the highest number of calls as the last calling terminal among the extension terminals 2 registered in the call management table, and based on this identification result, it determines whether or not to set up automatic call forwarding for extension terminals 2-3 linked to the call management table. In this case, three extension terminals 2-1, 2-2, and 2-3 (each with a call count of "1") are identified as extension terminals 2 with the highest number of calls as the last calling terminal. If multiple extension terminals 2 are identified, the main unit 1 further identifies the extension terminal with the most recent last call date and time (in this case, extension terminal 2-1). Since extension terminal 2-1 is not extension terminal 2-3 linked to this call management table, the main unit 1 sets up automatic call forwarding to extension terminal 2-3 linked to this call management table, with extension terminal 2-1 as the call forwarding destination (S135). Then, the main unit 1 sends call forwarding information, including information about the call forwarding destination (extension terminal 2-1), to extension terminal 2-3, which is set to automatically forward calls (S136), and extension terminal 2-3 displays the call forwarding information received from the main unit 1 (S137).

[0028] Next, the details of the main unit 1 that constitutes the internal telephone system according to this embodiment will be described.

[0029] Furthermore, since existing key telephones with a proxy answering function, equipped with a display unit such as an LCD (Liquid Crystal Display) and function keys for receiving various requests, can be used as extension terminal 2, a detailed explanation of them will be omitted.

[0030] Figure 5 is a schematic diagram of the functional configuration of the main unit 1.

[0031] As shown in the figure, the main unit 1 includes an internal telephone network interface unit 10, an external telephone network interface unit 11, a call control unit 12, a relay unit 13, a call management table storage unit 14, a call monitoring unit 15, a call management table update unit 16, an automatic call forwarding setting unit 17, a call forwarding information transmission unit 18, and a destination information transmission unit 19.

[0032] The internal telephone network interface unit 10 is an interface for connecting to the internal telephone network 5, and the external telephone network interface unit 11 is an interface for connecting to the external telephone network 4.

[0033] The call control unit 12 works in conjunction with the extension terminal 2 to perform call control processing, thereby establishing a call path between the extension terminal 2 and the external terminal 3 or another extension terminal 2. The call control unit 12 also has a proxy answering function, an incoming call forwarding function, and a hold forwarding function.

[0034] The relay unit 13 relays calls between the internal terminal 2 and the external terminal 3 or other internal terminals 2 via the call path established by the call control unit 12.

[0035] The call management table storage unit 14 stores a call management table for each extension terminal 2.

[0036] Figure 6 is a schematic diagram showing an example of the registered contents in the call management table storage unit 14.

[0037] As shown in the diagram, the call management table storage unit 14 stores a call management table 140 associated with each extension terminal 2. The call management table 140 registers a call management record 141 for each extension terminal 2 that has a history of being the end-call terminal (the party to whom the call ended) with the caller of a call directed to that extension terminal 2 associated with the call management table 140. The call management record 141 has a field 142 in which the identification information of the extension terminal 2 that has a history of being the end-call terminal is registered, a field 143 in which the number of calls made as the end-call terminal is registered, and a field 144 in which the date and time of the last call as the end-call terminal is registered.

[0038] The call monitoring unit 15 monitors the call status with the caller when a call destined for any extension terminal 2 arrives at the call control unit 12. Once the call with the caller has ended, it identifies the call end date and time and the terminal used for the call termination, and notifies the call management table update unit 16 of this along with the call's destination.

[0039] The call management table update unit 16 updates the call management table 140 associated with the destination notified by the call monitoring unit 15, based on the call terminal at the time of call termination and the call termination date and time notified by the call monitoring unit 15 along with the destination. Specifically, if a call management record 141 containing the identification information of the call terminal at the time of call termination notified by the call monitoring unit 15 is registered in the call management table 140 associated with the destination notified by the call monitoring unit 15, the call count registered in field 143 of this call management record 141 is incremented by one, and the call termination date and time registered in field 143 of this call management record 141 is updated to the call termination date and time notified by the call monitoring unit 15. Furthermore, if a call management record 141 containing the identification information of the call terminal at the time of call termination, as notified by the call monitoring unit 15, is not registered in the call management table 140 linked to the destination notified by the call monitoring unit 15, a new call management record 141 is added to this call management table 140, and the identification information of the call terminal at the time of call termination, the call count "1", and the call termination date and time notified by the call monitoring unit 15 are registered in fields 142 to 144 of this added call management record 141.

[0040] When the call management table 140 stored in the call management table storage unit 14 is updated, the automatic call forwarding setting unit 17 sets or cancels automatic call forwarding for the extension terminal 2 associated with the call management table 140 based on the updated registration contents of the call management table 140. Specifically, from the call management table 140, the call management record 141 with the most calls (if there are multiple call management records 141 with the most calls, the call management record 141 with the most recent last call date and time is extracted) is then checked. If an extension terminal 2 other than the extension terminal 2 linked to the call management table 140 is registered as the terminal that ended the call in the field 142 of this call management record 141, then automatic call forwarding is set to this terminal that ended the call as the forwarding destination for the extension terminal 2 linked to the call management table 140. If the extension terminal 2 linked to the call management table 140 is registered as the terminal that ended the call, then automatic call forwarding is not set for the extension terminal 2 linked to the call management table 140 (if automatic call forwarding is set, that setting is canceled). Furthermore, if call management record 141 is not registered in call management table 140 (i.e., call management table 140 has been initialized), automatic call forwarding will not be set for extension terminal 2 linked to call management table 140 (if automatic call forwarding is set, that setting will be canceled).

[0041] When automatic call forwarding is set to any extension terminal 2 by the automatic call forwarding setting unit 17, the call forwarding information transmission unit 18 transmits call forwarding information, which is information about the call forwarding destination, to the extension terminal 2.

[0042] When the call control unit 12 automatically forwards an incoming call, the destination information transmission unit 19 transmits destination information, which is information regarding the destination of the call, to the call forwarding destination.

[0043] The functional configuration of the main unit 1 shown in Figure 5 can be implemented in hardware using integrated logic ICs such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays), or in software using a computer such as a DSP (Digital Signal Processor). Alternatively, it may be implemented as a process in a general-purpose computer such as a PC equipped with a CPU, memory, auxiliary storage devices such as hard disks and flash memory, and a communication interface such as a NIC (Network Interface Card), by having the CPU load a predetermined program from the auxiliary storage device into memory and execute it.

[0044] Figure 7 is a flowchart illustrating the incoming call processing of the main unit 1.

[0045] This flow is initiated when a call destined for any of the extension terminals 2 arrives at the call control unit 12 via the external telephone network interface unit 11 or the internal telephone network interface unit 10.

[0046] First, the call control unit 12 determines whether automatic call forwarding is set up on the extension terminal 2 which is the destination of the incoming call (S200). If automatic call forwarding is not set up (NO in S200), it sends a call to the extension terminal 2 which is the destination of the call via the extension telephone network interface unit 10, with the specification of ringtone 1 (normal ringtone) (S201). On the other hand, if automatic call forwarding is set up (YES in S200), it sends a call to the extension terminal 2 which is the destination of the call forwarding via the extension telephone network interface unit 10, with the specification of ringtone 2 (ringtone for call forwarding), and also transmits the destination information of the incoming call (S202).

[0047] Next, when the call control unit 12 receives a response or proxy response to a call sent to the destination or call forwarding destination (YES in S203), it sends a response to the caller of the incoming call, establishing a communication channel with the responder or proxy responder and also establishing a communication channel with the caller. Then, it forwards the established communication channels to the relay unit 13 (S204). This enables communication between the responder or proxy responder and the caller.

[0048] Subsequently, when the call control unit 12 receives a call hold transfer request from an extension terminal 2 (the responder or a proxy responder) that is currently on a call via the extension telephone network interface unit 10 (YES in S205), it puts the call with the caller on hold and sends the call to the extension terminal 2 specified in the call hold transfer request (S206).

[0049] Then, when a response or proxy response is received to the call sent to the hold / transfer destination (YES in S207), the call path with the extension terminal 2 that requested the hold / transfer is released, and a new call path is established with the responder or proxy responder to the call sent to the hold / transfer destination. The hold on the call path with the caller is then released, the connection destination of this call path is changed to the newly established call path, and the call is forwarded between the two call paths to the relay unit 13 (S208). This enables communication between the responder or proxy responder to the call sent to the hold / transfer destination and the caller. The process then returns to S205.

[0050] On the other hand, if a request to cancel the call transfer is received from the call transfer requestor without receiving a response or proxy response to the call sent to the transfer destination (NO in S207) (YES in S209), the call path with the caller is released from the hold, and the system returns to S205 without changing the destination of this call path.

[0051] Furthermore, when the call control unit 12 determines that the call has been terminated between the caller and their counterpart (YES in S210), it releases the call path to the caller and the call counterpart, respectively, and terminates the call between them. In response, the call monitoring unit 15 identifies the extension terminal 2, which is the counterpart to the caller at the time the call was terminated, as the termination terminal (S211). The call management table update unit 16 then notifies the call management table update unit 16 of the identification information of the termination terminal, along with the call termination date and time and the extension terminal 2 that is the destination of the call. In response, the call management table update unit 16 updates the call management table 140 stored in the call management table storage unit 14 based on the notification from the call monitoring unit 15 (S212). Specifically, if a call management record 141 containing the identification information of the call terminal at the time of call termination, as notified by the call monitoring unit 15, is registered in the call management table 140 linked to the call destination notified by the call monitoring unit 15, the call count registered in this call management record 141 is incremented by 1, and the call termination date and time registered in this call management record 141 is updated to the call termination date and time notified by the call monitoring unit 15. On the other hand, if a call management record 141 containing the identification information of the call terminal at the time of call termination, as notified by the call monitoring unit 15, is not registered in the call management table 140 linked to the call destination notified by the call monitoring unit 15, a new call management record 141 is added to this call management table 140, and the identification information of the call terminal at the time of call termination, the call count "1", and the call termination date and time notified by the call monitoring unit 15 are registered in this call management record 141.

[0052] Figure 8 is a flowchart illustrating the automatic call forwarding setting process of the main unit 1.

[0053] This flow is initiated when the call management table update unit 16 updates one of the call management tables 140 in the call management table storage unit 14.

[0054] First, the automatic call forwarding setting unit 17 determines whether or not the call management record 141 is stored in the updated call management table 140 (hereinafter referred to as the updated call management table 140) (S220). If the call management record 141 is not stored in the updated call management table 140 (initialization of the call management table 140) (NO in S220), the automatic call forwarding setting unit 17 does not set automatic call forwarding for the extension terminal 2 associated with the updated call management table 140. If automatic call forwarding is set for this extension terminal 2, it cancels the setting (S225).

[0055] On the other hand, if the updated call management table 140 contains a call management record 141 (YES in S220), the automatic call forwarding setting unit 17 searches the updated call management table 140 for the call management record 141 containing the most frequent call count (S221). Then, the automatic call forwarding setting unit 17 determines whether multiple call management records 141 with the most frequent call counts were found at this time (S222).

[0056] If there is only one call management record 141 containing the highest number of calls found in the updated call management table 140 (NO in S222), the automatic call forwarding setting unit 17 determines whether the call terminal at the time of call termination (the call terminal with the highest number of calls) registered in this call management record 141 is the extension terminal 2 itself that is linked to the updated call management table 140 (S224).

[0057] Furthermore, if the terminal with the most calls at the end of a call is the extension terminal 2 linked to the updated call management table 140 (YES in S224), the automatic call forwarding setting unit 17 does not set automatic call forwarding for the extension terminal 2 linked to the updated call management table 140. If automatic call forwarding is set for this extension terminal 2, it is canceled (S225).

[0058] On the other hand, if the terminal that makes the most calls at the end of a call is not the extension terminal 2 linked to the updated call management table 140 (NO in S224), the automatic call forwarding setting unit 17 sets up automatic call forwarding to the extension terminal 2 linked to the updated call management table 140, using this terminal as the call forwarding destination (S226). Then, the call forwarding information transmission unit 18 transmits call forwarding information, which is information about the call forwarding destination, to the extension terminal 2 for which automatic call forwarding has been set by the automatic call forwarding setting unit 17, via the extension telephone network interface unit 10 (S227).

[0059] Furthermore, in S222, if there are multiple call management records 141 that contain the highest number of calls found in the updated call management table 140 (YES in S222), the automatic call forwarding setting unit 17 searches for the call management record 141 that contains the most recent last call date and time from among these call management records 141 (S223). The automatic call forwarding setting unit 17 then determines whether the call terminal at the time of call completion (the call terminal at the time of call completion with the highest number of calls and the most recent call record) registered in the call management record 141 that contains both the highest number of calls and the most recent last call date and time is the extension terminal 2 linked to the updated call management table 140 itself (S224). If the call terminal at the time of call completion with the highest number of calls and the most recent call record is the extension terminal 2 linked to the updated call management table 140 (YES in S224), the automatic call forwarding setting unit 17 does not set up automatic call forwarding for the extension terminal 2 linked to the updated call management table 140. If automatic call forwarding is set on extension terminal 2, disable it (S225).

[0060] On the other hand, if the terminal that has made the most calls and has the most recent call history is not the extension terminal 2 linked to the updated call management table 140 (NO in S224), the automatic call forwarding setting unit 17 sets up automatic call forwarding to the extension terminal 2 linked to the updated call management table 140, using this terminal as the call forwarding destination (S226). Then, the call forwarding information transmission unit 18 transmits call forwarding information, which is information about the call forwarding destination, to the extension terminal 2 for which automatic call forwarding has been set by the automatic call forwarding setting unit 17, via the extension telephone network interface unit 10 (S227).

[0061] Figure 9 is a flowchart illustrating the call management table initialization process of the main unit 1.

[0062] This flow is initiated when the call management table update unit 16 receives an initialization request from any extension terminal 2 via the extension telephone network interface unit 10.

[0063] First, the call management table update unit 16 identifies the call management table 140 associated with the extension terminal 2 that is the source of the initialization request from the call management table storage unit 14 as the target for initialization (S230).

[0064] Then, the call management table update unit 16 deletes all call management records 141 from the call management table 140 to be initialized and initializes the call management table 140 to be initialized (S231).

[0065] One embodiment of the present invention has been described above.

[0066] In this embodiment, when the main unit 1 finishes a call with the caller of a call destined for any extension terminal 2, it updates the call management table 140, which is linked to the destination extension terminal 2 and stored in the call management table storage unit 14, and increments the call count of the terminal at the time of call termination by one. When any call management table 140 is updated, if the terminal at the time of call termination in the call management record 141 with the highest number of calls in the call management table 140 is the extension terminal 2 linked to the call management table 140, the main unit 1 does not set up automatic call forwarding for this extension terminal 2 (or cancels the setting). On the other hand, if the terminal at the time of call termination is not an extension terminal 2 linked to the call management table 140, the main unit 1 sets up automatic call forwarding for the extension terminal 2 linked to the call management table 140, with this terminal at the time of call termination as the call forwarding destination. Therefore, the call is forwarded to extension terminal 2 of a user who frequently communicates with the caller, that is, an extension terminal 2 of a user who is highly likely to be able to effectively handle the caller of a call addressed to extension terminal 2. As a result, incoming calls addressed to any of the extension terminals 2 can be answered more quickly without making the caller wait for a long time.

[0067] Furthermore, if the updated call management table 140 contains multiple call management records 141 with the highest number of calls, the system identifies the call management record 141 with the most recent last call date and time from among these records. If the terminal that ended the call for the identified call management record 141 is the extension terminal 2 associated with this call management table 140, then automatic call forwarding is not set (or is deactivated) for this extension terminal 2. On the other hand, if the terminal that ended the call is not an extension terminal 2 associated with this call management table 140, then automatic call forwarding is set for the extension terminal 2 associated with this call management table 140, with this terminal as the call forwarding destination. As a result, the call is sent to the extension terminal 2 of the user that most recently handled the call as the terminal that ended the call, from among the extension terminals 2 that frequently communicate with the caller. This means that the user who is most likely to be able to handle the call is the first to respond to the caller of the call destined for an extension terminal 2. This further reduces the possibility of keeping the caller waiting.

[0068] Furthermore, in this embodiment, when the main unit 1 receives an initialization request from any extension terminal 2, it initializes the call management table 140 that is associated with that extension terminal 2 and stored in the call management table storage unit 14. Once the call management table 140 is initialized, the main unit 1 does not set up automatic call forwarding for the extension terminal 2 associated with this call management table 140. If automatic call forwarding is set up, it is canceled. As a result, the user of the extension terminal 2 can cancel the automatic call forwarding set up on their extension terminal 2 with a simple operation.

[0069] Furthermore, in this embodiment, when automatic call forwarding is set on extension terminal 2, the main unit 1 sends call forwarding information, which is information about the call forwarding destination, to extension terminal 2, causing the extension terminal 2 to display the call forwarding information. As a result, users of extension terminal 2 on which automatic call forwarding is set can find out whether or not automatic call forwarding is set on their extension terminal 2, and if automatic call forwarding is being performed, they can find out the call forwarding destination, thus improving convenience.

[0070] Furthermore, in this embodiment, when the main unit 1 receives a call destined for extension terminal 2, it uses different ringing sounds depending on whether it is sending the call to the intended extension terminal 2 or to an extension terminal 2 set as the call forwarding destination (Ringing sound 1: Normal ringing sound, Ringing sound 2: Ringing sound for call forwarding). Therefore, users of extension terminal 2 can determine whether a call received on extension terminal 2 is intended for them based on the ringing sound, thereby improving convenience.

[0071] Furthermore, in this embodiment, when the main unit 1 receives a call destined for an extension terminal 2 that has automatic call forwarding enabled, and forwards this call to the call forwarding destination, it sends destination information, which is information about the destination of this call, to the call forwarding destination. As a result, the user of the extension terminal 2 at the call forwarding destination can know the original destination of the call that arrived on their extension terminal 2, improving convenience.

[0072] It should be noted that the present invention is not limited to the embodiments described above, and numerous modifications are possible within the scope of its essence.

[0073] For example, in the above embodiment, if there are multiple call management records 141 with the highest number of calls in the updated call management table 140, the main unit 1 identifies the call management record 141 with the most recent last call date and time from among these call management records 141. If the call terminal at the time of the identified call management record 141's end is not an extension terminal 2 associated with this call management table 140, the main unit 1 sets up automatic call forwarding to the extension terminal 2 associated with this call management table 140, using this call terminal as the call forwarding destination. However, the present invention is not limited thereto and may be modified as follows.

[0074] The number of calls is divided into several groups, including the number of answers, the number of answers given by proxy, the number of calls transferred, and the number of calls transferred by proxy. When a call with an extension terminal 2 is terminated, the main unit 1 increments the number of answers in the call management record 141 of the terminal at the time of termination, which is stored in the call management table 140 associated with this destination, if the terminal at the time of termination is the destination of the call, increments the number of answers given by proxy if it is extension terminal 2 which answered on behalf of the destination of the call, increments the number of calls transferred if it is the destination of the call, and increments the number of calls transferred by proxy if it is extension terminal 2 which answered on behalf of the destination of the call. Then, the main unit 1 searches the updated call management table 140 for the call management record 141 with the highest number of calls (the sum of the counts for each of multiple groups, including the number of answered calls, the number of delegated answered calls, the number of transferred answered calls, and the number of transferred delegated answered calls). If there are multiple call management records 141 with the highest number of calls, the main unit 1 identifies the call management record 141 with the highest number of answered calls from among them. If there are multiple call management records 141 with the highest number of answered calls, the main unit 1 narrows down the results sequentially as follows: From among the multiple call management records 141 with the highest number of answered calls, the main unit 1 identifies the call management record 141 with the highest number of delegated answered calls. If there are multiple call management records 141 with the highest number of transferred answered calls, the main unit 1 identifies the call management record 141 with the highest number of transferred delegated answered calls from among them. Then, if the call management record 141 is finally identified as the only relevant record, and the terminal used to end the call in this call management record 141 is not the extension terminal 2 associated with this call management table 140, then automatic call forwarding is set to the extension terminal 2 associated with this call management table 140, with this terminal being the destination for incoming call forwarding.

[0075] If it is not possible to narrow down the results to a single call management record 141, automatic call forwarding will not be set for the extension terminal 2 associated with this call management table 140. If automatic call forwarding is set, it will be canceled. Alternatively, all of the call terminals at the time of the end of the call for any remaining call management records 141 after the final filtering may be called as the forwarding destination for incoming calls destined for the extension terminal 2 associated with this call management table 140.

[0076] Furthermore, in the above embodiment, the main unit 1 determines whether or not automatic call forwarding is necessary for the extension terminal 2 linked to the call management record 141 when the call management record 141 is updated. However, the determination of whether or not automatic call forwarding is necessary may be performed at other times. For example, the determination of whether or not automatic call forwarding is necessary may be performed according to a predetermined schedule (specification of repetition period, specification of time, specification of day of the week, specification of date, etc.). [Explanation of Symbols]

[0077] 1: Main unit 2-1~2-n: Internal terminals 3: External terminals 4: External telephone network 5: Internal telephone network 10: Internal Telephone Network Interface Unit 11: External telephone network interface unit 12: Call control unit 13: Relay unit 14: Call management table storage unit 15: Call Monitoring Department 16: Call Management Table Update Department 17: Automatic call forwarding setting unit 18: Call forwarding information transmission unit 19: Destination Information Transmission Section

Claims

1. An extension telephone system comprising a plurality of extension terminals and a main unit that accommodates the plurality of extension terminals, The main device is, For each extension terminal, a call management table storage means stores a call management table in which the caller of a call destined for that extension terminal is linked to the caller's call count and the last call date and time with the caller at the end of the call, When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding is sent to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means is provided to identify the caller at the end of the call, When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. The system includes an automatic call forwarding setting means that, if the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, does not set up automatic call forwarding for the extension terminal linked to the call management table, and if the extension terminal with the most calls is not the extension terminal linked to the call management table, sets up automatic call forwarding for the extension terminal linked to the call management table, with the extension terminal with the most calls as the call forwarding destination. The aforementioned call management table update means is: When a call destined for the aforementioned extension terminal is received and the call recipient is identified by the call monitoring means, the call management table stored in the call management table storage means, which is linked to the said extension terminal, is updated to increment the call count of the said call recipient by one, and the last call date and time of the said call recipient is updated. The aforementioned automatic call forwarding setting means is If there are multiple extension terminals with the most calls in the call management table, the extension terminal with the most calls and the most recent last call date and time is identified from among them. If the extension terminal with the most calls and the most recent last call date and time is the extension terminal linked to the call management table, automatic call forwarding is not set for the extension terminal linked to the call management table. If the extension terminal with the most calls and the most recent last call date and time is not the extension terminal linked to the call management table, automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls and the most recent last call date and time as the call forwarding destination. An internal telephone system characterized by the following features.

2. An extension telephone system comprising a plurality of extension terminals and a main unit that accommodates the plurality of extension terminals, The main device is, Each extension terminal is provided with a call management table storage means that stores a call management table in which the caller of a call destined for that extension terminal is linked to the number of calls made by that caller at the end of the call, When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding is sent to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means is provided to identify the caller at the end of the call, When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. The system includes an automatic call forwarding setting means that, if the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, does not set up automatic call forwarding for the extension terminal linked to the call management table, and if the extension terminal with the most calls is not the extension terminal linked to the call management table, sets up automatic call forwarding for the extension terminal linked to the call management table, with the extension terminal with the most calls as the call forwarding destination. The aforementioned extension terminal is It has an initialization request transmission means that transmits an initialization request for the call management table in accordance with the operator's instructions, In the main unit, The aforementioned call management table update means is: When the initialization request is received from the extension terminal, the call management table, which is associated with the extension terminal and registered in the call management table storage means, is initialized. The aforementioned automatic call forwarding setting means is If the call management table is initialized by the call management table update means, and automatic call forwarding is set on the extension terminal associated with the call management table, then the automatic call forwarding setting is canceled. An internal telephone system characterized by the following features.

3. An extension telephone system comprising a plurality of extension terminals and a main unit that accommodates the plurality of extension terminals, The main device is, Each extension terminal is provided with a call management table storage means that stores a call management table in which the caller of a call destined for that extension terminal is linked to the number of calls made by that caller at the end of the call, When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding is sent to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means is provided to identify the caller at the end of the call, When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. Automatic call forwarding setting means: If the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, then automatic call forwarding is not set for the extension terminal linked to the call management table; if the extension terminal with the most calls is not the extension terminal linked to the call management table, then automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls being the call forwarding destination. If automatic call forwarding is set on the extension terminal by the automatic call forwarding setting means, the system includes a call forwarding information transmission means that transmits call forwarding information, which is information regarding the call forwarding destination, to the extension terminal. The aforementioned extension terminal is When the incoming call forwarding information is received from the main unit, the incoming call forwarding information is displayed. An internal telephone system characterized by the following features.

4. An extension telephone system comprising a plurality of extension terminals and a main unit that accommodates the plurality of extension terminals, The main device is, Each extension terminal is provided with a call management table storage means that stores a call management table in which the caller of a call destined for that extension terminal is linked to the number of calls made by that caller at the end of the call, When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding is sent to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means is provided to identify the caller at the end of the call, When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. The system includes an automatic call forwarding setting means that, if the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, does not set up automatic call forwarding for the extension terminal linked to the call management table, and if the extension terminal with the most calls is not the extension terminal linked to the call management table, sets up automatic call forwarding for the extension terminal linked to the call management table, with the extension terminal with the most calls as the call forwarding destination. The aforementioned incoming call processing means is The ringing sound emitted by the extension terminal when sending the incoming call to the destination extension terminal is to be different from the ringing sound emitted by the extension terminal when sending the call to the extension terminal to which the call is forwarded. An internal telephone system characterized by the following features.

5. An extension telephone system comprising a plurality of extension terminals and a main unit that accommodates the plurality of extension terminals, The main device is, Each extension terminal is provided with a call management table storage means that stores a call management table in which the caller of a call destined for that extension terminal is linked to the number of calls made by that caller at the end of the call, When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding is sent to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means is provided to identify the caller at the end of the call, When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. Automatic call forwarding setting means: If the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, then automatic call forwarding is not set for the extension terminal linked to the call management table; if the extension terminal with the most calls is not the extension terminal linked to the call management table, then automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls being the call forwarding destination. When the incoming call processing means sends the call to the extension terminal to which the call is forwarded, the system includes destination information transmission means that transmits destination information, which is information about the extension terminal to which the call is headed, to the extension terminal. The aforementioned extension terminal is If the destination information is received from the main unit while the main unit is ringing due to an incoming call, the destination information will be displayed. An internal telephone system characterized by the following features.

6. An extension telephone system according to any one of claims 2 to 5, In the main unit, The aforementioned call management table includes: The person on the other end of a call with the caller of the aforementioned extension terminal is registered in conjunction with the number of calls and the date and time of the last call with the caller. The aforementioned call management table update means is: When a call destined for the aforementioned extension terminal is received and the call recipient is identified by the call monitoring means, the call management table stored in the call management table storage means, which is linked to the said extension terminal, is updated to increment the call count of the said call recipient by one, and the last call date and time of the said call recipient is updated. The aforementioned automatic call forwarding setting means is If there are multiple extension terminals with the most calls in the call management table, the extension terminal with the most calls and the most recent last call date and time is identified from among them. If the extension terminal with the most calls and the most recent last call date and time is the extension terminal linked to the call management table, automatic call forwarding is not set for the extension terminal linked to the call management table. If the extension terminal with the most calls and the most recent last call date and time is not the extension terminal linked to the call management table, automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls and the most recent last call date and time as the call forwarding destination. An internal telephone system characterized by the following features.

7. A main unit that accommodates multiple extension terminals, For each extension terminal, a call management table storage means stores a call management table in which the caller of a call destined for that extension terminal is linked to the caller's call count and the last call date and time with the caller at the end of the call, When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding is sent to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means is provided to identify the caller at the end of the call, When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. The system includes an automatic call forwarding setting means that, if the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, does not set up automatic call forwarding for the extension terminal linked to the call management table, and if the extension terminal with the most calls is not the extension terminal linked to the call management table, sets up automatic call forwarding for the extension terminal linked to the call management table, with the extension terminal with the most calls as the call forwarding destination. The aforementioned call management table update means is: When a call destined for the aforementioned extension terminal is received and the call recipient is identified by the call monitoring means, the call management table stored in the call management table storage means, which is linked to the said extension terminal, is updated to increment the call count of the said call recipient by one, and the last call date and time of the said call recipient is updated. The aforementioned automatic call forwarding setting means is If there are multiple extension terminals with the most calls in the call management table, the extension terminal with the most calls and the most recent last call date and time is identified from among them. If the extension terminal with the most calls and the most recent last call date and time is the extension terminal linked to the call management table, automatic call forwarding is not set for the extension terminal linked to the call management table. If the extension terminal with the most calls and the most recent last call date and time is not the extension terminal linked to the call management table, automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls and the most recent last call date and time as the call forwarding destination. A main unit characterized by the following features.

8. A program that causes a computer to function as a main unit accommodating multiple extension terminals, For each extension terminal, a call management table storage means stores a call management table in which the caller of a call destined for that extension terminal is linked to the caller's call count and the date and time of the last call with the caller at the end of the call. When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the extension terminal, the call forwarding destination of the extension terminal is forwarded to the extension terminal; if automatic call forwarding is not set up on the extension terminal, the call forwarding means sends the call to the extension terminal. When a call destined for the aforementioned extension terminal is received, a call monitoring means identifies the caller of the call at the end of the call. When the call monitoring means identifies the call recipient, the call management table update means updates the call management table stored in the call management table storage means, which is linked to the extension terminal, and increments the call count of the call recipient by one. If the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, then automatic call forwarding is not set for the extension terminal linked to the call management table. If the extension terminal with the most calls is not the extension terminal linked to the call management table, then the computer functions as an automatic call forwarding setting means, setting the extension terminal with the most calls as the call forwarding destination and automatically forwarding calls to the extension terminal linked to the call management table. The aforementioned call management table update means is: When a call destined for the aforementioned extension terminal is received and the call recipient is identified by the call monitoring means, the call management table stored in the call management table storage means, which is linked to the said extension terminal, is updated to increment the call count of the said call recipient by one, and the last call date and time of the said call recipient is updated. The aforementioned automatic call forwarding setting means is If there are multiple extension terminals with the most calls in the call management table, the extension terminal with the most calls and the most recent last call date and time is identified from among them. If the extension terminal with the most calls and the most recent last call date and time is the extension terminal linked to the call management table, automatic call forwarding is not set for the extension terminal linked to the call management table. If the extension terminal with the most calls and the most recent last call date and time is not the extension terminal linked to the call management table, automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls and the most recent last call date and time as the call forwarding destination. A program characterized by the following features.

9. A method for forwarding incoming calls in an extension telephone system comprising a plurality of extension terminals and a main unit that accommodates the plurality of extension terminals, The main device is, For each extension terminal, a call management table is stored that associates the caller of a call destined for that extension terminal with the caller at the end of the call, the number of calls made by that caller, and the date and time of the last call with that caller. When a call destined for the aforementioned extension terminal arrives, if automatic call forwarding is set up on the destination extension terminal, the call is forwarded to the destination extension terminal; if automatic call forwarding is not set up on the destination extension terminal, the call is forwarded to the destination extension terminal. The system identifies the person the caller of the call had spoken to at the end of the call, updates the call management table stored in association with the extension terminal that is the destination of the call, increments the call count of the identified person by one, and updates the last call date and time of that person. If the extension terminal with the most calls in the call management table is the extension terminal linked to the call management table, then no call forwarding destination is set for the extension terminal linked to the call management table. If the extension terminal with the most calls is not the extension terminal linked to the call management table, then automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls being the call forwarding destination. If there are multiple extension terminals with the highest number of calls in the call management table, the extension terminal with the most recent last call date and time is identified from among the extension terminals with the highest number of calls. If the extension terminal with the most calls and the most recent last call date and time is the extension terminal linked to the call management table, automatic call forwarding is not set for the extension terminal linked to the call management table. If the extension terminal with the most calls and the most recent last call date and time is not the extension terminal linked to the call management table, automatic call forwarding is set for the extension terminal linked to the call management table, with the extension terminal with the most calls and the most recent last call date and time as the call forwarding destination. A method for forwarding incoming calls, characterized by the following features.

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