Abstract:
Upon detecting the origination of an emergency call to a public safety answering point (PSAP), an IP softphone places this call over a cellular network rather than utilizing data communication. By placing the emergency call over the cellular system, the call is automatically routed by the cellular system to the appropriate PSAP, and the cellular system also provides to the PSAP the location of the IP softphone. The IP softphone utilizes a peripheral that provides the radio frequency circuitry necessary to place the emergency call to the PSAP.

Description:
TECHNICAL FIELD 
     This invention relates to telephones in general, and in particular, to the capability of placing telephone calls to the correct public safety answering points for emergency needs. 
     BACKGROUND OF THE INVENTION 
     In the office environment, IP softphones are interconnected via data connections to a customer communication switching system. A particular IP softphone may not be located in the same geographical area as the customer business communication switching system with which it is operating. Indeed, a particular IP softphone may not even be in the same state as the communication switching system. Even if the IP softphone is in the same building as the communication switching system, the communication switching system has no automatic means for determining the physical position of the IP softphone within the building. Such position information would have to be manually entered into the communication switching system. In addition, this manual information would have to be updated as the IP softphone moves throughout the building. For example, if a business traveler is in New Jersey but is utilizing a communication switching system in Colorado, upon placing a 911 emergency call, this call will be routed to a public safety answering point (PSAP) in Colorado. Since the communication switching system has no capability to route the call to a PSAP in New Jersey or to determine the location of IP softphone, the business traveler can only hang up their IP softphone and find a traditional telephone to place the 911 emergency call. Even if the business traveler is physically located in the same building as the communication switching system in Colorado, the dispatcher at the PSAP may not be able to assist the business traveler in response to a 911 emergency call since the dispatcher has no idea where in the office building the business traveler is. 
     SUMMARY OF THE INVENTION 
     This invention is directed to solving these and other problems and disadvantages of the prior art. According to an embodiment of the invention, upon detecting the origination of an emergency call to a public safety answering point (PSAP), the IP softphone will place this call over the cellular network rather than utilizing data communication. By placing the emergency call over the cellular system, the call is automatically routed by the cellular system to the appropriate PSAP, and the cellular system also provides to the PSAP the location of the IP softphone. Advantageously, the IP softphone utilizes a peripheral that provides the radio frequency circuitry necessary to place the emergency call to the PSAP. 
     These and other advantages and features of the present invention will become apparent from the following description of an illustrative embodiment of the invention taken together with the drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  illustrates, in block diagram form, an embodiment of an IP softphone utilizing the present invention; 
         FIG. 2  illustrates, in flow chart form, the steps performed by the IP softphone in implementing an embodiment of the invention; and 
         FIG. 3  illustrates, in block diagram form, another embodiment of an IP softphone utilizing the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an embodiment of a system for implementing the invention. IP softphone  100  is registered as a telephone with enterprise communication switching system  116  via wide area network (WAN)  112 . WAN  112  may advantageously be a local area network (LAN) or, as is well known in the art, the Internet, ATM network, etc. One skilled in the art could readily envision that IP softphone  100  was not registered with enterprise communication switching system  116  but rather is simply a telephone device utilizing WAN  112  for communication with other softphones such as softphone  111 . Enterprise communication switching system  116  may advantageously be an Avaya Definity® business communication switching system (commonly referred as PBX). Advantageously, as is well known in the art, enterprise communication switching system  116  can be any other type of system such as an H.323 calling system. Cellular network  108  is a well-known commercially available cellular switching system. PSAP  113  is a well-known public safety answering point. Public telephone network  109  is a switching public telephone network. 
     IP softphone  100  comprises personal computer (PC)  104  that provides overall control for the softphone. The audio interface is provided by elements  101 – 103 . IP interface  106  provides interconnection to WAN  112 . Radio interface  107  is intragal part of PC  104  and provides the cellular radio interface for placing telephone calls via cellular network  108 . Radio interface  107  is the radio circuitry found in any commercial cellular telephone and is well known by those skilled in the art. 
     For normal telephone calls, IP softphone  100  communicates via WAN  112  with enterprise communication switching system  116 . IP softphone  100  appears to be another telephone set to enterprise communication switching system  116  from the point of view of call processing. If the user of IP softphone  100  originates a normal call, this telephone call is placed via WAN  112  to enterprise communication switching system  116 . However, if the user of IP softphone  100  places an emergency call by dialing advantageously “911”, PC  104  originates this call via radio interface  107  through cellular network  108 . Cellular network  108  in combination with public telephone network  109  sets up the emergency call to PSAP  113 . In addition, cellular network  108  provides the physical location of IP softphone  100  to PSAP  113 . 
       FIG. 2  illustrates, in flow chart form, the steps performed by PC  104  in implementing the invention. After being started, decision block  201  determines if the operation being performed in call processing is a call origination. If the answer is no, the call processing operation is processed in a normal manner by block  203  before transferring control back to decision block  201 . If the answer in decision block  201  is that the call processing operation is a call origination, decision block  202  determines if it is an emergency call to a PSAP. If the answer is no, block  207  performs normal processing before transferring control back to decision block  201 . If the answer in decision block  202  is yes, block  204  activates radio interface  107 , and block  206  places a call to the PSAP via cellular network  108  and public telephone network  109  before returning control back to decision block  201 . 
       FIG. 3  illustrates another embodiment of a system for implementing the invention. IP softphone  300  is registered as a telephone with enterprise communication switching system  316  via wide area network (WAN)  312 . WAN  312  may advantageously be a local area network (LAN) or, as is well known in the art, the Internet, ATM network, etc. One skilled in the art could readily envision that IP softphone  300  was not registered with enterprise communication switching system  316  but rather is simply a telephone device utilizing WAN  312  for communication with other softphones such as softphone  311 . Enterprise communication switching system  316  may advantageously be an Avaya Definity® business communication switching system (commonly referred as PBX). Advantageously, as is well known in the art, enterprise communication switching system  316  can be any other type of system such as an H.323 calling system. Cellular network  308  is a well-known commercially available cellular switching system. PSAP  313  is a well-known public safety answering point. Public telephone network  309  is a switching public telephone network. 
     IP softphone  300  comprises personal computer (PC)  304  that provides overall control for the softphone. The audio interface is provided by elements  301 – 303 . IP interface  306  provides interconnection to WAN  312 . Universal Serial Bus interface (USB)  307  connects cellular radio circuit  318  to PC  304 . USB  307  is well known by those skilled in the art. Cellular radio circuit  318  is external to PC  304  and is used by PC  304  for placing telephone calls via cellular network  308 . Cellular radio circuit  318  is the radio circuitry found in any commercial cellular telephone and is well known by those skilled in the art. 
     For normal telephone calls, IP softphone  300  communicates via WAN  312  with enterprise communication switching system  316 . IP softphone  300  appears to be another telephone set to enterprise communication switching system  316  from the point of view of call processing. If the user of IP softphone  300  originates a normal call, this telephone call is placed via WAN  312  to enterprise communication switching system  316 . However, if the user of IP softphone  300  places an emergency call by dialing advantageously “911”, PC  304  originates this call via USB  307  and cellular radio circuit  318  through cellular network  308 . Cellular network  308  in combination with public telephone network  309  sets up the emergency call to PSAP  313 . In addition, cellular network  308  provides the physical location of IP softphone  300  to PSAP  313 . PC  304  performs similar steps to those illustrated in  FIG. 2 . 
     Of course, various changes and modifications to the illustrated embodiment described above will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the following claims except insofar as limited by the prior art.