Telephone System

Abstract

To provide a call control technology capable of park-holding a call on a mobile phone terminal by a telephone system.SOLUTION: In a telephone system, a telephone control device 10 exchanges call control messages with an FMC server 32 via an FMC gateway 12 to establish a first call between a mobile phone terminal 42 connected to a mobile phone network 52 and an opposite device 40, the FMC gateway 12 saves call information related to the first call in a call control DB 12A when the first call is established, the FMC gateway 12 converts a special number transmission request notified from the FMC server 32 in response to a transfer operation at the mobile phone terminal 42 into a park hold request and notifies the telephone control device 10 of the request, and the telephone control device 10 acquires call information regarding the first call from the call control DB 12A in response to the park hold request regarding the first call notified from the FMC gateway 12, and establishes and parks a second call with the opposite device 40 on the basis of the call information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a call control technique used when parking a call in a telephone system. [Background technology]

[0002] Telephone systems such as key telephone systems and PBX systems have the function of transferring calls between extension telephone terminals by temporarily putting the call on hold. There are two types of hold used for transferring calls: system hold, which allows any extension telephone terminal in the system to answer the call again, and park hold, which allows only extension telephone terminals belonging to a specific group called a park group to answer the call again (see, for example, Non-Patent Document 1). In particular, park hold is often used in business offices, where calls are often transferred within park groups set up for each department. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Instruction Manual - Multifunction Telephone Edition - PLATIA", pp.74-75, [online], SAXA Corporation, [Retrieved December 27, 2020], Internet <URL:https: / / support.saxa.co.jp / file / manual / platia / pt_operation_manual_takinou_v3.10.pdf> Summary of the Invention [Problem to be solved by the invention]

[0004] Mobile carriers provide a fixed mobile convergence (FMC) service that uses an FMC server connected to the mobile phone network to turn mobile phone terminals into extensions, and some telephone systems use this FMC service to accommodate mobile phone terminals as extensions and provide an extension call service with existing extension telephone terminals. This makes it possible for staff members who are out to call clients from their own mobile phone terminals via the telephone system, and to answer external calls to staff members from their mobile phone terminals via the telephone system.

[0005] Here, the telephone system provides advanced services to the internal telephone terminals by exchanging various control commands between the telephone control device and the internal telephone terminals, but the functions of the mobile phone terminals that can be used with the FMC service are limited to making and answering calls, and transmitting DTFM (Dual-Tone Multi-Frequency) signals during a call.

[0006] Therefore, in the FMC service, when a call answered in the office is handed over to the mobile phone terminal of a person in charge who is out, for example, this can be achieved with relatively simple call control in which the person in charge who is out sends a special number indicating a second response to the parked call to the telephone control device via the FMC server using a DTFM signal, in other words, a special number call, to the mobile phone terminal of the person in charge who is out. However, when a call answered by a mobile phone terminal is put on park hold using a telephone control device, complex call control is required, such as transferring the call to be put on park hold from the FMC gateway to the telephone control device, making it difficult to achieve this using only the FMC gateway.

[0007] The present invention has been made to solve these problems, and has as its object to provide a call control technique that enables a call made on a mobile phone terminal to be parked on hold in a telephone system. [Means for solving the problem]

[0008] In order to achieve the above object, the telephone system according to the present invention includes a telephone control device that switches and connects a plurality of extension telephone terminals to an IP telephone network and a mobile telephone network, and an FMC gateway that relays and converts call control messages exchanged between an FMC server of the mobile telephone network and the telephone control device, and the telephone control device exchanges call control messages with the FMC server via the FMC gateway, thereby communicating with mobile telephone terminals connected to the mobile telephone network. Connected to the IP telephone network The FMC gateway is configured to establish a first call between an opposing device, obtain call information regarding the first call from a call information database in response to a park hold request for the first call notified from the FMC gateway, and establish a second call with the opposing device based on the call information and place the call on park hold. The FMC gateway is configured to store the call information regarding the first call in the call information database when the first call is established, convert a special number call request notified from the FMC server in response to a transfer operation on the mobile phone terminal into the park hold request and notify the telephone control device.

[0009] In addition, one configuration example of the above telephone system according to the present invention is configured such that the telephone control device establishes a third call with the mobile phone terminal in response to the park hold request from the FMC gateway, and after placing the second call on park hold, notifies the mobile phone terminal of the park number related to the second call by voice via the third call.

[0010] In addition, one configuration example of the above telephone system according to the present invention is configured such that the telephone control device puts the second call on hold, disconnects the first call, and after notifying the caller of the park number by voice, disconnects the third call.

[0011] In addition, in one configuration example of the above telephone system according to the present invention, the special number calling request is a special number calling request using a special number calling service of the FMC server, and the FMC gateway is configured to convert the special number calling request from the FMC server into a park hold special number calling request that is preset in the telephone control device. Effect of the Invention

[0012] According to the present invention, it is possible to park a call made to a mobile phone terminal on a telephone system. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing the configuration of a telephone system. [Diagram 2] FIG. 2 is an explanatory diagram showing an example of the configuration of the call information DB. [Diagram 3] FIG. 3 is a flowchart showing an example of a park hold operation. [Figure 4] FIG. 4 is a sequence diagram showing an example of a park hold operation. [Diagram 5] FIG. 5 is a sequence diagram showing an example of a park hold operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Next, an embodiment of the present invention will be described with reference to the drawings. [Telephone System] First, a telephone system 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of the telephone system. This telephone system 1 is made up of a key telephone system or a PBX system used in facilities such as offices, and includes a plurality of extension telephone terminals (EX terminals) 20, and a telephone control device (IP-PBX) 10 configured to switch and connect these extension telephone terminals 20 to an IP telephone network 51 and a mobile phone network 52. The telephone system 1 also includes a VoIP gateway (VoIP-GW) 11 and an FMC gateway (FMC-GW) 12.

[0015] [Principle of the invention] Generally, when a mobile phone terminal uses an FMC service, it can make and receive calls, as well as send DTFM signals during a call. In an FMC service, a hold service is usually provided that holds a call on a mobile phone terminal based on a special hold number notified by the mobile phone terminal using a DTFM signal. As a result, for example, when the mobile phone terminal 42 is making a first call with the opposing device 40, by using the hold service, the first call can be put on hold in the FMC server 32. Therefore, if a second call can be established between the telephone control device 10 and the opposing device 40, the second call can be put on park hold in the telephone control device 10, and then the first call can be disconnected.

[0016] Here, in order to establish a second call with the telephone control device 10 and to notify the FMC server of the disconnection of the first call, call information regarding the first call is required. However, there is no service that provides such call information from the FMC server 32. In this case, if the first call was originally established using the FMC service on the telephone control device 10, the telephone control device 10 and the FMC server 32 exchange call control messages via the FMC gateway 12, so that the FMC gateway 12 can obtain call information regarding the first call from the call control messages.

[0017] The present invention focuses on the fact that call information can be acquired by such an FMC gateway 12, and is configured so that the FMC gateway 12 acquires call information related to the first call from call control messages exchanged between the telephone control device 10 and the FMC server 32, and stores the call information in a call information database (hereinafter, called call information DB) 12A. This enables the telephone control device 10 to acquire call information related to the first call from the call information DB 12A.

[0018] In addition, the FMC service provides a special number calling service that calls a destination corresponding to a special number based on a special number calling from a mobile phone terminal that specifies a specific number set in advance. Therefore, in the above example, if the special number calling service is used to place the first call on hold and then a call is made from the mobile phone terminal 42 to the telephone control device 10 via the FMC server 32, a third call between the mobile phone terminal 42 and the telephone control device 10 can be established. The present invention is configured such that the FMC gateway 12 converts the special number call from the FMC server 32 described above into a park hold special number call and notifies the telephone control device 10. This allows the telephone control device 10 to receive the special number call from the mobile phone terminal 42 as a park hold request, and this park hold request can be used as a trigger to start call control such as obtaining call information regarding the first call described above and establishing the second call.

[0019] [Telephone System Details] Next, with reference to FIG. 1, the telephone control device 10, the VoIP gateway 11, and the FMC gateway 12, which constitute the telephone system 1 according to the present embodiment, will be described in detail.

[0020] [Telephone control device] The telephone control device 10 consists of a main device of a key telephone system or a PBX device of a PBX system, and has the function of providing an extension connection service to the extension telephone terminal 20 by exchanging various call control messages with the extension telephone terminal 20, and the function of providing a call service via the IP telephone network 51 to the extension telephone terminal 20 by exchanging call control messages with a call control server 31 of the IP telephone network 51.

[0021] The telephone control device 10 also has a function of providing various FMC services that the FMC server has to preset mobile phone terminals 41, 42 by exchanging call control messages with the FMC server 32 of the mobile phone network 52. The FMC services include a service of proxy answering, i.e. picking up, an incoming call to the extension telephone terminal 20 at the mobile phone terminals 41, 42, a service of parking and holding calls from the mobile phone terminals 41, 42 at the telephone control device 10, and a service of re-answering calls parked and held at the telephone control device 10 at the mobile phone terminals 41, 42.

[0022] The telephone control device 10 also includes an interactive voice response (IVR) 10A that transmits preset voice guidance to the mobile phone terminals 41 and 42. This IVR 10A is used to notify the mobile phone terminals 41 and 42 of the park number of the parked call by voice. The IVR 10A has a call control function independent of the telephone control device 10, exchanging call control messages with the telephone control device 10 using, for example, SIP (Session Initiation Protocol).

[0023] In addition, the telephone control device 10 has a function of establishing a first call between mobile phone terminals 41, 42 connected to the mobile phone network 52 and an opposing device 40 connected to the IP telephone network 51 or the mobile phone network 52 by exchanging call control messages with the FMC server 32 via the FMC gateway 12, and a function of acquiring call information regarding the first call from the call information DB 12A of the FMC gateway 12 in response to a park hold request for the first call notified from the FMC gateway 12, and establishing a second call with the opposing device 40 and putting the call on park hold based on the call information.

[0024] In addition, the telephone control device 10 has a function of establishing a third call with the mobile phone terminal 42 in response to a park hold request from the FMC gateway 12, placing the second call on park hold, and then notifying the mobile phone terminal 42 of the park number related to the second call by voice from the IVR 10A via the third call, and a function of disconnecting the first call after placing the second call on park hold, notifying the park number by voice, and then disconnecting the third call.

[0025] [VoIP Gateway] The VoIP gateway 11 is a network device configured to relay and convert call control messages exchanged between a call control server 31 connected to an IP telephone network 51 and a telephone control device 10 based on a call control protocol such as SIP.

[0026] [FMC Gateway] The FMC gateway 12 is a network device configured to relay and convert call control messages exchanged between the FMC server 32 connected to the mobile phone network 52 and the telephone control device 10 . The FMC gateway 12 includes a call information DB 12A for temporarily storing call information related to a call that is the subject of park hold in the telephone control device 10. The call information DB 12A may be provided inside the FMC gateway 12, or may be configured as a separate database device that is externally connected to the FMC gateway 12 via a communication line.

[0027] Fig. 2 is an explanatory diagram showing an example of the configuration of the call information DB. As shown in Fig. 2, in the call information DB 12A, to-tag information indicating the called terminal, from-tag information indicating the calling terminal, and CALLID information for identifying the call are registered as a set for each userID information for identifying a mobile phone terminal. These pieces of call information can be obtained from the header information of the call control message exchanged between the telephone control device 10 and the FMC server 32 when a call is established.

[0028] In addition, when a first call is established between the mobile phone terminals 41, 42 and the opposing device 40 via the telephone control device 10, the FMC gateway 12 has the function of storing call information regarding the first call in the call control DB 12A, and converting a transfer request regarding the first call notified from the FMC server 32 in response to a transfer operation on the mobile phone terminals 41, 42 into a park hold request and notifying the telephone control device 10.

[0029] [Operation of the first embodiment] Next, a park-on-hold operation of the telephone system 1 according to the present embodiment will be described with reference to Fig. 3 to Fig. 5. Fig. 3 is a flowchart showing an example of the park-on-hold operation. Figs. 4 and 5 are sequence diagrams showing an example of the park-on-hold operation. Here, we will explain an example in which a mobile phone terminal 42 picks up an incoming call from the opposing device 40 to the telephone control device 10 using the FMC service, starts a first call with the opposing device 40, and then puts the first call on hold using the FMC service and places the call on park hold at the telephone control device 10.

[0030] In addition, the telephone control device 10 and the FMC server 32 will be described as an example in which call control is performed based on SIP. Also, it is assumed that the telephone number of the opposing device 40 is "050-xxxx". Also, it is assumed that the representative telephone number of a specific group of the telephone control device 10 is "03-yyyy", and the telephone number of the extension telephone terminal 20 belonging to that group is "715-2001". Also, it is assumed that the telephone number of the mobile telephone terminal 41 is "71-31001", and the telephone number of the mobile telephone terminal 42 is "71-31002".

[0031] 3 and 4, first, when an incoming call to the group is notified from the VoIP gateway 11 in response to a call from the opposing device 40, the telephone control device 10 notifies the extension telephone terminals 20 belonging to the group of the incoming call (INVITE 7152001 from:050-xxxx). In addition, the telephone control device 10 notifies the mobile phone terminals 42 belonging to the group of the incoming call to the group by using, for example, a push notification of a pre-installed mobile app. In contrast, when a pickup operation is performed on the mobile phone terminal 42 (step S100), the mobile phone terminal 42 notifies the FMC server 32 of a special number dialing (DIAL 71-91-XXXX) including the gateway number (71) of the FMC gateway 12, a pickup special number (91) indicating a pickup request, and the group number (XXXX) of the group.

[0032] This special number dialing call is converted to a special number dialing call (INVITE 7191XXXX) by the FMC server 32, and notified from the FMC server 32 to the FMC gateway 12, where it is converted to a special number dialing call (INVITE 91XXXX) for pick-up by the telephone control device 10, and notified to the telephone control device 10. In response to the pickup special number call from the FMC gateway 12, the telephone control device 10 notifies the internal telephone terminal 20 belonging to the group of a cancellation (CANCEL / 200 OK) to stop the incoming call, and returns a response (200 OK) to the pickup special number call to the FMC gateway 12.

[0033] The FMC gateway 12 notifies the FMC server 32 of this response, and the mobile phone terminal 42 receives the response from the FMC server 32. As a result, the FMC gateway 12 acquires, for example, call information included in the pickup special number transmission from the FMC server 32, and stores it in the call information DB 12A (step S101). Moreover, the telephone control device 10 returns a response (200 OK) to the VoIP gateway 11, and the response is notified to the opposing device 40 from the VoIP gateway 11 via the call control server 31. As a result, a first call is established between the mobile phone terminal 42 and the opposing device 40, and a voice call is started (step S102).

[0034] During a first call, if a hold operation for the first call is performed on the mobile phone terminal 42 using the hold service of the FMC service, and a hold special number (DIAL 1) is sent as a DTMF signal (step S103), the FMC server 32 puts the first call on hold (step S104) and begins sending a hold tone to the opposing device 40.

[0035] Next, when a special number dialing call (DIAL 718#) including the gateway number (71) of the FMC gateway 12 and the special number (8#) is sent as a DTMF signal by the mobile phone terminal 42 using the special number dialing service of the FMC service to the telephone control device 10 (step S105), the FMC server 32 converts the special number dialing call into a special number call (INVITE 718 from 7131002) and notifies the FMC gateway 12 (step S106).

[0036] The FMC gateway 12 converts the special number call from the FMC server 32 into an IVR special number call (INVITE 7192 from 7131002) for the IVR 10A and notifies the telephone control device 10. At this time, the special number call from the FMC server 32 is excluded from the storage of call information. This allows efficient use of memory resources of the call information DB 12A. In response to the IVR special number call from the FMC gateway 12, the telephone control device 10 notifies the IVR 10A of the incoming call, and in response to the response (200 OK) from the IVR 10A, returns a response (200 OK) to the FMC gateway 12, and this response (200 OK) is returned from the FMC gateway 12 to the FMC server 32. As a result, a third call in a silent state is established between the mobile phone terminal 42 and the IVR 10A of the telephone control device 10 (step S107).

[0037] In addition, the IVR 10A of the telephone control device 10 acquires call information on the first call being made by the mobile phone terminal 42, which is the source of the IVR special number call, from the call information DB 12A of the FMC gateway 12 in response to the IVR special number call from the FMC gateway 12 (step S108). As a result, SIP Dialog information (to-tag, from-tag, CALLID) is acquired as the call information on the first call. Next, as shown in FIG. 5, the IVR 10A notifies the telephone control device 10 of a call establishment request (REFER 951, . . . , REFER 955) with the opposing device 40, including the park special number (95) of the telephone control device 10, based on the acquired call information.

[0038] 5, in response to a call establishment request from the IVR 10A, the telephone control device 10 notifies the VoIP gateway 11 of a call switching request (re-INVITE) for changing the destination of the first call to the telephone control device 10. The VoIP gateway 11, which receives this, switches the connection destination of the voice packet forming the call with the opposing device 40 to the telephone control device 10. As a result, a second call is established between the telephone control device 10 and the opposing device 40, and the first call is switched to the second call in the opposing device 40 (step S109). The telephone control device 10 associates this second call with a group to which the mobile phone terminal 42 belongs and places the call on hold (step S110).

[0039] After that, the IVR 10A notifies the FMC gateway 12 of the disconnection (BYE / 200 OK) regarding the first call. As a result, the FMC gateway 12 notifies the FMC server 32 of the disconnection, and the first call is disconnected (step S111). Also, the IVR 10A transmits voice guidance indicating the park number related to the second call that has been parked by the telephone control device 10 to the mobile phone terminal 42 via the third call, and notifies the mobile phone terminal 42 of the park number by voice (step S112). Also, the IVR 10A notifies the telephone control device 10 of disconnection (BYE / 200 OK) in response to the call switching request.

[0040] After sending the voice guidance, the IVR 10A notifies the telephone control device 10 of the disconnection (BYE) of the third call. As a result, the disconnection of the third call is notified from the telephone control device 10 to the FMC server 32 via the FMC gateway 12, and the third call is disconnected (step S113). The third notification may also be disconnected from the mobile phone terminal 42 at the time when the park number is notified by voice guidance.

[0041] Next, the telephone control device 10 notifies the extension telephone terminal 20 belonging to the group of the park number of a display instruction (NOTIFY park slot-5 ON) indicating that a parked call is on hold, for example, specifying a park slot (park slot-5). As a result, an LED indicating that a parked call is on hold in the corresponding park slot is flashed on the extension telephone terminal 20 to which the notification is sent.

[0042] Thereafter, when the user of mobile phone terminal 42 notifies the user of mobile phone terminal 41 of the park number, for example by voice call, verbally, or other method, and a park response operation is performed on mobile phone terminal 41, a special number dial call (DIAL 7181) including the gateway number (71) of FMC gateway 12 and a park response special number (81) indicating a park response is notified from mobile phone terminal 41 to FMC server 32.

[0043] This special number dialing call is converted by the FMC server 32 into a special number call (INVITE 7181 from 7131001), which is then notified from the FMC server 32 to the FMC gateway 12. The FMC gateway 12 converts this call into a park response special number call (INVITE 951 from 7131001) for the telephone control device 10, which is then notified to the telephone control device 10. In response to the park response special number call from the FMC gateway 12, the telephone control device 10 notifies the VoIP gateway 11 of a call switching request (re-INVITE) for changing the destination of the fifth call to the mobile phone terminal 41.

[0044] The VoIP gateway 11, which has received this, switches the connection destination of the voice packets forming the call with the opposing device 40 to the mobile phone terminal 41 via the FMC gateway 12. The second call is switched to a fourth call between the mobile phone terminal 41 and the opposing device 40. As a result, a voice call is started between the mobile phone terminal 41 and the opposing device 40.

[0045] After that, the telephone control device 10 notifies the extension telephone terminal 20 belonging to the group of the park number of a display instruction (NOTIFY park slot-5 OFF) indicating that the parked call is released by specifying, for example, the park slot (park slot-5). As a result, the LED indicating that the parked call is on hold in the corresponding park slot is turned off on the extension telephone terminal 20 to which the notification is sent.

[0046] [Advantages of this embodiment] In this manner, in this embodiment, the telephone control device 10 establishes a first call between a mobile phone terminal 42 connected to a mobile phone network 52 and the opposing device 40 by exchanging call control messages with the FMC server 32 via the FMC gateway 12, the FMC gateway 12 stores call information regarding the first call in the call control DB 12A when the first call is established, the FMC gateway 12 converts a special number call request notified by the FMC server 32 in response to a transfer operation on the mobile phone terminal 42 into a park hold request and notifies the telephone control device 10, and the telephone control device 10 acquires call information regarding the first call from the call control DB 12A in response to the park hold request regarding the first call notified by the FMC gateway 12, and based on the call information, establishes a second call with the opposing device 40 and places it on park hold.

[0047] As a result, the call information on the first call established by the telephone control device 10 using the FMC service is automatically stored in the call information DB 12A by the FMC gateway 12. As a result, even if the FMC server 32 does not provide a service for notifying call information, the telephone control device 10 can easily obtain the call information on the first call. Also, in the FMC gateway 12, the special number call from the FMC server 32 is converted into a park hold special number call and notified to the telephone control device 10. As a result, the telephone control device 10 can easily receive the special number call from the mobile phone terminal 42 as a park hold request, and can start call control such as obtaining the call information on the first call and establishing the second call, as described above, by using this park hold request as a trigger. Therefore, the first call from the mobile phone terminal 42 can be parked in the telephone system 1.

[0048] In addition, in this embodiment, the telephone control device 10 may establish a third call with the mobile phone terminal 42 in response to a park hold request from the FMC gateway 12, and after placing the second call on park hold, may voice notify the mobile phone terminal 42 of the park number related to the second call via the third call. This allows a third call to be automatically established by the simple process of returning a response to a park hold request, and can be used for voice notification of the park number.

[0049] In the present embodiment, the telephone control device 10 may put the second call on hold, then disconnect the first call, and after notifying the caller of the park number by voice, disconnect the third call. This makes it possible to efficiently disconnect the first and third calls related to the mobile phone terminal 42 whose function has been completed.

[0050] In addition, in this embodiment, the transfer request for the first call may be composed of a transfer special number call based on the transfer service of the FMC server 32, and the FMC gateway 12 may convert the transfer special number call into a park hold special number call that is preset in the telephone control device 10. As a result, even if the FMC service does not provide a special number calling service for park hold, it is possible to request park hold from the mobile phone terminal 42 to the telephone control device 10 using a general special number calling service.

[0051] [Extended embodiment] Although the present invention has been described above with reference to the embodiment, the present invention is not limited to the above embodiment. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. [Explanation of symbols]

[0052] 1...telephone system, 10...telephone control device (IP-PBX), 10A...interactive voice response device (IVR), 11...VoIP gateway, 12...FMC gateway, 12A...call information database (call information DB), 20...extension telephone terminal, 31...call control server, 32...FMC server, 40...opposing device, 41, 42...mobile phone terminal, 51...IP telephone network, 52...mobile phone network.

Claims

1. a telephone control device for switching and connecting a plurality of extension telephone terminals to an IP telephone network and a mobile telephone network; an FMC gateway that relays and converts call control messages exchanged between an FMC server of the mobile phone network and the telephone control device; the telephone control device establishes a first call between a mobile phone terminal connected to the mobile phone network and an opposing device connected to the IP telephone network by exchanging call control messages with the FMC server via the FMC gateway, acquires call information regarding the first call from a call information database in response to a park hold request regarding the first call notified from the FMC gateway, and establishes a second call with the opposing device and parks the second call based on the call information; The FMC gateway stores call information regarding the first call in the call information database when the first call is established, converts a special number call request notified from the FMC server in response to a transfer operation on the mobile phone terminal into the park hold request, and notifies the telephone control device.

1. A telephone system comprising:

2. 2. The telephone system of claim 1, a call control device that establishes a third call with the mobile phone terminal in response to the park hold request from the FMC gateway, places the second call on park hold, and then notifies the mobile phone terminal of the park number related to the second call by voice via the third call.

3. 3. The telephone system of claim 2, a call control unit that holds the second call on hold, disconnects the first call, and notifies the caller of the park number by voice, and then disconnects the third call.

4. In the telephone system according to any one of claims 1 to 3, The special number calling request is a special number calling request using a special number calling service of the FMC server, The FMC gateway converts the special number call from the FMC server into a park hold special number call that is preset in the telephone control device.

1. A telephone system comprising:

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