Patent Publication Number: US-2005122984-A1

Title: Roaming communication system over internet

Description:
BACKGROUND OF INVENTION  
      1. Field of the Invention  
      The present invention relates to a telephone communication system, and more specifically, to a roaming telephone communication system created across the Internet by using dynamic Internet Protocol (IP) addresses.  
      2. Description of the Prior Art  
      With the growing popularity of high-speed Internet connections, it is now feasible for Voice over Internet Protocol (VoIP) phone calls to be made over the Internet. One main advantage of VoIP is that VoIP phone calls are significantly less expensive than phone calls made solely over a public switched telephone network (PSTN).  
      Please refer to  FIG. 1 .  FIG. 1  is a functional block diagram of a VoIP system  10  according to the prior art. The VoIP system  10  connects a first voice gateway  16  to a second voice gateway  22 . Each of the first and second voice gateways  16  and  22  is connected to each other through respective Internet connections  14  and  20 . The Internet connections  14  and  20  may be an xDSL connection or another suitable broadband Internet connection. The Internet connection  20  provides a static IP address to each of the first and second voice gateways  16  and  22 . The first voice gateway  16  is connected to a normal telephone  18  for allowing the normal telephone  18  to make phone calls through the Internet  12 . The second voice gateway  22  is connected to a private branch exchange (PBX)  24 , which provides telephone service to a plurality of phone extensions  26 .  
      Each of the first and second voice gateways  16  and  22  converts voice signals into voice packets for transmitting the voice packets via the Internet  12 . Likewise, the first and second voice gateways  16  and  22  convert voice packets received through the Internet  12  into voice signals that are then sent to the appropriate normal telephone  18  or phone extension  26 . Unfortunately, the VoIP system  10  requires each of the first and second voice gateways  16  and  22  to be connected to the Internet  12  through a static IP address. Not only are static IP addresses more expensive than dynamic IP addresses, but also neither of the first and second voice gateways  16  and  22  can be easily moved since the static IP address service would have to be moved to another location as well.  
     SUMMARY OF INVENTION  
      It is therefore an objective of the claimed invention to provide a roaming communication system that can be connected through dynamic IP addresses in order to solve the above-mentioned problems.  
      According to the claimed invention, a roaming communication system includes a first local telephone system, a first communication module connected to the first local telephone system and connected to the Internet through a first dynamic IP address, a second local telephone system, and a second communication module connected to the second local telephone system and connected to the Internet through a second dynamic IP address. The first and second communication modules are each capable of converting voice signals respectively received from the first and second local telephone systems to voice packets for transmission over the Internet and are capable of restoring voice packets received through the Internet into voice signals. The roaming communication system also includes a host connected to the Internet through a static IP address. The host is used to control voice packet traffic between the first communication module and the second communication module.  
      It is an advantage of the claimed invention that the first and second communication modules can easily be connected to the roaming communication system through a connection to the Internet using a dynamic IP address. Thus, new communication modules can easily be added to the roaming communication system at any time, and without additional cost involved to register a static IP address. Moreover, the roaming communication system only requires a single host, and does not require a voice gateway at each geographical location of the roaming communication system.  
      These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is a functional block diagram of a VoIP system according to the prior art.  
       FIG. 2  is a diagram of a roaming communication system according to a first embodiment of the present invention.  
       FIG. 3  is a diagram of a roaming communication system according to a second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
      Please refer to  FIG. 2 .  FIG. 2  is a diagram of a roaming communication system  50  according to a first embodiment of the present invention. The roaming communication system  50  allows any type of telephone to make a phone call over the Internet  52 , so long as the telephone is connected to the roaming communication system  50  in one of several ways. As shown in the top right portion of  FIG. 2 , a public switched telephone network (PSTN)  72  is connected to the roaming communication system  50  through a data access arrangement (DAA) module  70 . The DAA module  70  contains one or more telephone line connectors (such as RJ11 connectors) for connecting the DAA module  70  to one or more telephone lines of the PSTN  72 . In addition, the DAA module  70  also contains a network cable connector (such as an RJ45 connector) for connecting the DAA module  70  to an IP sharing device  62 . The IP sharing device  62  contains a hub or switch, and is used to share an Internet connection  60  with each network device connected to the IP sharing device  62 . Unlike the VoIP system  10  of the prior art, the roaming communication system  50  only needs a dynamic IP address to be provided by the Internet connection  60 , and does not require a stable static IP address for connecting additional telephones or telephone networks to the roaming communication system  50 .  
      As shown in the middle right portion of  FIG. 2 , another public switched telephone network (PSTN)  72  is connected to the roaming communication system  50  through another data access arrangement (DAA) module  70 . The only difference is a hub  63  is connected to the IP sharing device  62  to share the Internet connection  60  to a telephone  64  in addition to the DAA module  70 . The telephone  64  has a network connector such as an RJ12 connector for connecting the telephone  64  to the hub  63 . Therefore, the telephone  64  can utilize the roaming communication system  50  through any shared or unshared connection to the Internet  52  using a dynamic IP address. Similarly, the PSTN  72  can also connect to the roaming communication system  50  via the DAA module  70 . The DAA module  70  and the telephone  64  both contain circuitry that converts voice signals into voice packets for transmitting the voice packets via the Internet  52 . Likewise, the circuitry also converts voice packets received through the Internet  52  into voice signals that are then sent to the respective telephone  64  or telephone line in the PSTN  72 .  
      Besides connecting the PSTN  72  to the roaming communication system  50 , a private branch exchange (PBX)  82  can also be used. As shown in the bottom portion of  FIG. 2 , the PBX  82  is connected to the roaming communication system  50  through a SLIC module  80 . Like the DAA module  70 , the SLIC module  80  contains a network cable connector (such as an RJ45 connector) for connecting the SLIC module  80  to the IP sharing device  62 . The PBX  82  is connected to a plurality of phone extensions  84  for allowing the phone extensions  84  to utilize the roaming communication system  50  through the PBX  82  and the SLIC module  80 .  
      The DAA modules  70  and the SLIC module  80  are all connected to the Internet  52  through Internet connections  60  that provide dynamic IP addresses. The entire roaming communication system  50  can be controlled by a network private branch exchange (PBX) host  90 . The network PBX host  90  is connected to the Internet  52  through another Internet connection  88 , which provides a static IP address. Another telephone  64  is connected to the network PBX host  90 , and a server  92  is connected directly to the telephone  64 . The network PBX host  90  provides telephone service to each of the telephones  64 , to phones in the PSTNs  72 , and to the phone extensions  84  in the PBX  82  that utilize the roaming communication system  50  to make telephone calls. The server  92  is used to coordinate all data transmitted and received in the roaming communication system  50 .  
      The roaming communication system  50  is said to be roaming because each of the telephones  64 , the phones in the PSTN  72 , and the phone extensions  84  in the PBX  82  can be connected to the Internet  52  anywhere that a dynamic IP address is present. A static IP address can also be used, but is not necessary when using the present invention.  
      In  FIG. 2 , all devices are connected to the roaming communication system  50  through wired connections using the IEEE 802.3 protocol. Please refer to  FIG. 3 .  FIG. 3  is a diagram of a roaming communication system  100  according to a second embodiment of the present invention. The roaming communication system  100  is similar to the roaming communication system  50  shown in  FIG. 2 , and the same reference numbers will be used to refer to the same parts. Instead of using wired connections to connect the DAA modules  70 , the telephone  64 , and the SLIC module  80 , the roaming communication system  100  utilizes access points  102  to wirelessly connect with the devices in the roaming communication system  100 . As shown, the DAA modules  70 , the telephone  64 , and the SLIC module  80  can all communicate with the access points  102  using at least one of the many IEEE 802.11x protocols.  
      In contrast to the prior art, the present invention roaming communication system utilizes dynamic IP addresses to connect all network devices to the roaming communication system. Only the host device requires a static IP address so that the other network devices have a stable address in which to communicate with the host. Thus, telephones, PSTNs, and PBXs can be added to the roaming communication system at any time, and without additional cost involved to register a static IP address. Moreover, the roaming communication system only requires a single host, and does not require a server or voice gateway at each geographical location of the roaming communication system.  
      Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.