Abstract:
A user self-expandable extension network system and its dialing and answering processes are applied to an extension network which consists of a plurality of extensions. An extension will send a detecting signal to locate the host phone and regard the host phone as a session initiation protocol (SIP) proxy server after receiving the reporting signal of the host phone. Therefore, the extension can be dialed or receive a phone call without being set up by the assistance of a professional technician.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates to an extension network system and a dialing and answering method of the same, and more particularly to an IP phone extension network in which the extension will detect a host phone and assign it as a session initiation protocol proxy server, and a dialing and answering method of the same. 
         [0003]    2. Related Art 
         [0004]    An IP phone relates to a telephone communication technology, which uses a voice over internet protocol (VoIP) by an internet or IP network technology. 
         [0005]    A session initiation protocol (SIP) relates to an application level control protocol, which establishes a VoIP connection by applying a request-response structure for one or more participants to start, correct, or end a conversation. Since the SIP only involves processing the signal part of a conversation, the SIP usually works with other protocols, such as a real-time transport protocol (RTP), to transmit a voice or an image of the communication. Still, some operations in the SIP are similar to those in traditional telephones, such as dialing, ringing or being busy. The SIP uses a proxy server to provide functions, such as a registration and/or inquiring a route to the target party. The registration plays an important role in the SIP since every IP phone has its own identification. Therefore, registering its unique identification to a proxy server makes the proxy server capable of identifying each IP phone. 
         [0006]    In the past, most IP phones were used in the internal network of large companies or organizations for managing technicians, to simultaneously provide a voice and a data service through a network. As the Internet has become popular and the demand of long distance communication has increased dramatically, the IP phone has applied to be used in long distance communication. In addition, since competition between the telecommunication companies of the major cities of the world is getting intense and since the telecommunication regulation has been modified, the IP phone has started to be used in a fixed network communication. Due to the advantages of low communication cost, low equipment cost, capable of expansion and improving quality of conversation, replacing a traditional phone with the IP phone becomes a trend either in enterprises or families. Therefore, the international telecommunication enterprises often regard the IP phone as a potential competitor of the traditional telecommunication technique. 
         [0007]    In the current IP phone network, an extension number is associated with a unique IP address, which in turn represents one IP device (e.g. IP Phone or gateway). If a person needs multiple phones at different locations, each phone will be assigned a different extension number. It is generally undesirable since the person wants to be reached by the same number especially in a private environment (e.g. different rooms of the house) and it is difficult to memorize the correct phone number to dial for the different location. If multiple phones, placed at different locations, need to share the same extension number, it can only be accomplished by a hunt group or a forward process. However, the above processes need a server capable of providing such functions and also need a professional technician to set it up correctly. The IP phone can not, like a traditional phone, be set up by persons buying a telephone and connect it themselves when they want a private phone extension network. Therefore, it is inconvenient to set up an IP extension phone, except for processional technicians. 
       SUMMARY OF INVENTION 
       [0008]    It is an object of the present invention to provide a private extension network system and method in order to let the IP extension be shared by multiple phones without being set up by a professional technician. 
         [0009]    An embodiment of a dialing process includes the following steps: an extension sending a request to a host phone; the host phone modifying the identification data in the request to represent itself and sending the modified request to a SIP proxy server; after receiving a response from the SIP proxy server, the host phone sending the response to the extension which sends the request, and the extension receiving the response from the host phone. 
         [0010]    An embodiment of an answering process includes the following steps: after receiving a request from a SIP proxy server, the host phone sending the request to all extensions; after one of the extension is connected through, a response sent by the extension to the host phone; after receiving the response, the host phone sending a cancel ringing signal to the extensions which are not connected through. 
         [0011]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention will become more fully understood from the detailed description given below, which is for illustration only and thus is not limitative of the present invention, wherein: 
           [0013]      FIG. 1  is a structural diagram of an extension network system, in which a user may expand it by himself according to the invention; 
           [0014]      FIG. 2A  is a registration process flowchart of an extension network system, in which a user may expand it by himself according to the invention; 
           [0015]      FIG. 2B  is a dialing process flowchart of an extension network system, in which a user may expand it by himself according to the invention; 
           [0016]      FIG. 2C  is an answering process flowchart of an extension network system, in which a user may expand it by himself according to the invention; 
           [0017]      FIG. 3A  is a diagram showing an original extension network logical connection according to the invention; and 
           [0018]      FIG. 3B  is a diagram showing a self-expanded extension network logical connection according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]      FIG. 1  is a diagram showing an embodiment of a system according to the present invention. The present invention includes a host phone  111  and a first extension  112 . The host phone  111  establishes a logical connection with the first extension  112  by a network  150 , and in the meantime, the host phone  11  also establishes a logical connection with a session initiation protocol (SIP) proxy server  140  by the network  150 . Also refer to  FIG. 2B . When the first extension  112  is dialed, the first extension  112  will send a request to the host phone  111  (step  230 ). After the host phone  111  receives the request from the first extension  112 , the host phone  111  will change the identification data in the request from the representing first extension  112  to the representing host phone  111 , and send the modified request to the SIP proxy server  140  (step  240 ). The host phone  111  will then transfer a response from the SIP proxy server  140  to the first extension  112 , which responds to the request transferred from the first extension  112  to the SIP proxy server  140  by the host phone  111  (step  250 ). The first extension  112  will receive the expected response (step  260 ), and be capable of communicating. Based on  FIG. 1  and  FIG. 2C , when there is a coming call, the host phone  111  will receive a request transferred from the SIP proxy server  140  and transfer the request to the first extension  112  (step  270 ). When the first extension  112  connects through, it will send a response corresponding to the request to the host phone  111  (step  280 ). The host phone  111  will receive the response from the first extension  112  and send the modified response to the SIP proxy server  140  after changing the identification data in the response from the representing first extension  112  to the representing host phone  111  (step  291 ) and then wait for connection. 
         [0020]      FIG. 3A  is an illustrative embodiment of the system and the process according to the present invention. When a first user wants to make a phone call from a Hotel suite to a IP phone  130  of his house by the first extension  112  on the desk, the first extension  112  will send a first request ┌INVITE SIP: desk@room.hotel.tw SIP/2.0┘ to the host phone  111  beside the bed of the Hotel suite. The host phone  111  will change the identification data ┌desk┘ in the first request to its own identification data ┌bed┘, and send the modified first request ┌INVITE SIP: bed@room.hotel.tw SIP/2.0┘ to the SIP proxy server  140  of the hotel. Then, the first request will be transmitted through the internet to reach the IP phone  130  of the first user&#39;s house. The IP phone  130  will start ringing. When a second user picks up the IP phone  130 , the IP phone  130  will send a first response ┌200, OK┘, which is transmitted through the internet to the SIP proxy  140  of the hotel. The SIP proxy server  140  will transfer the first response to the host phone  111  beside the bed and the host phone  111  will then transfer the first response to the first extension  112  on the desk so that a connection is established. The first extension  112  transmits the voice data to the IP phone  130  by RTP. 
         [0021]    When the second user wants to use the IP phone  130  to make a phone call to the first user in the Hotel, the IP phone  130  will send a second request, which is similar to the first request, to the SIP proxy server  140  of the hotel through the internet. After receiving the second request, the SIP proxy server  140  will transfer the second request to the host phone  111 , and the host phone  111  will transfer the second request to the first extension  112  after receiving the second request from the SIP proxy server  140 . As a result, the first extension  112  will start ringing. When the first user picks up the first extension  112 , the first extension  112  will send a second response ┌200, Ok┘ to the host phone  111 . The host phone  111  will transfer the second response to the SIP proxy server  140  after it received the second response. Then connection is established. The first extension  112  transmits the voice data to the second IP phone  130  by RTP. 
         [0022]    If a second extension  113  is installed in the bathroom of the suite with respect to  FIG. 3B  and  FIG. 2A , the second extension  113  will send a detecting signal in order to detect the host phone  111  after it has been connected to the internet (step  211 ). The detecting technology is not limited to the UDP discovery packet. If the UDP discovery packet is used to detect the host phone  111 , the second extension  113  and the host phone  111  must have the same IP subnet  110 ; Otherwise, the UDP discovery packet can not correctly reach the host phone  111  and the second extension  113  may not be capable of detecting the host phone  111 . The host phone  111  will send a reporting signal to the second extension  113  after it received the detecting signal from the second extension  113  (step  212 ). After receiving the reporting signal from the host phone  111 , the second extension  113  will send registration data to the host phone (step  221 ) and the host phone will record the data of the second extension  113  to complete the registration (step  222 ). 
         [0023]    By the same process as described above, the first user may dial or pick up the phone in the bathroom. However, one more step is necessary for answering the phone call with respect to  FIG. 2C . After step  291 , the host phone  111  will send a canceling ringing signal to other extensions, which do not send the second response (step  292 ). For example, when the host phone  111  transfers the second request to the first extension  112  and the second extension  113 , the first extension  112  and the second extension  113  start ringing. After the first user has picked up the second extension  113 , the second extension  113  will send the second response to the host phone  111  and the host phone  111  will send a canceling ringing signal to other extensions that do not send the second response, which will be the first extension  112  in this embodiment. Therefore, the first extension  112  will stop ringing and the second extension  113  will transmit the voice data to the second extension  113  by the RTP. 
         [0024]    While the illustrative embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments, which do not depart from the spirit and scope of the invention. 
         [0025]    The present invention provides an extension network system by which a user can expand it himself. In the IP phone extension network, the extension will send a detecting signal to detect the host phone. When the host phone has received the detecting signal, it will send a reporting signal to the extension which sends the detecting signal and register the extension through the session initiation protocol (SIP) proxy server. Therefore the extension doesn&#39;t need a technician to transmit a request and a response with a host phone to process dialing and answering.