Abstract:
A call establishment method for Internet Telephony appliances consisting of two phases. The first phase is a method of notifying the Internet Telephony appliance of the called party that a VoIP call is being attempted. The second phase is for both systems to automatically log on to the Internet and to proceed through the procedure to establish the VoIP call.

Description:
TECHNICAL FIELD OF THE INVENTION 
     This invention relates generally to a method for facilitating Internet Telephony, and more specifically, to the method of connecting Internet Telephony calls. 
     BACKGROUND OF THE INVENTION 
     Internet Telephony makes use of the global connection of the Internet as an alternative voice carrier to enable that voice communications be carried out between different locations around the world. Voice is transmitted as IP packets over the Internet, hence the common term Voice-over-IP (VoIP) used to describe Internet Telephony. One major goal of Internet Telephony is to establish calls in a manner that is as simple as using normal telephone over the Public Switched Telephone Network (PSTN). 
     One important property of the PSTN network is that all PSTN devices, e.g., telephone sets, connect directly to the PSTN network at all times. When a caller needs to establish a call to another party, the caller needs only dial the telephone number of the party to call. The called party is alerted by the ringing of the telephone upon a successful connection. Both parties start to communicate when the called party picks up the telephone. 
     In contrast, dial-up Internet Telephony appliances do not attach directly to the Internet and therefore have finite Internet connection time. Internet Telephony requires that the appliances dial-up to the Internet over PSTN before VoIP communication can occur. However, these appliances are normally dormant unless a certain method is devised to generate events that will trigger them to log on to the Internet. These connections normally are only established for as long as they are in use, and are disconnected when they are no longer needed for reason of costs and availability. 
     Another important aspect of the PSTN infrastructure is the telephone numbering plan. Each PSTN connection has a unique identification or telephone number. A telephone on the PSTN can reach another telephone by simply dialing its unique telephone number. 
     A dial-up Internet connection in most cases does not have a fixed unique identification. Although each Internet connection does have a unique IP address, dial-up Internet connection is usually assigned with a dynamic IP address that differs each time the dial-up Internet connection is established. For dial-up Internet Telephony to occur, each Internet Telephony user must use a unique identifier and a method that performs translation of this unique identifier to the IP address of its dial-up Internet Telephony appliance. 
     Various call establishment methods have been adopted for dial-up Internet Telephony based on using existing PSTN and Internet infrastructure. Some of these methods are briefly described below along with their shortcomings. 
     The “User Look-up from Directory Services” method requires the caller to look up the party to call using some form of Directory Services or User Location Services (ULS). All users need to register their user identification and dynamic IP address with the directory server whenever they log on to Internet to use Internet Telephony. A caller will then be able to look up a registered user from a list of users to obtain the user dynamic IP address for establishing a VoIP call. A disadvantage of this method is the fact that a caller can only reach another party that has already logged on to the Internet and has registered with the directory server. 
     The “Prearranged Logon Time” method is an extension of the above method. It basically involves prearranging both users to log on to Internet at a predetermined time to establish a VoIP call. A different method of communication needs to take place for the time to be arranged. Generally, this can be done via an e-mail or a normal telephone call. The caller then obtains the dynamic IP address from a directory server using a known identifier such as an e-mail address. One shortcoming of this method is the inability to establish a VoIP call at anytime. 
     The “Auto Logon following Normal Telephone Call” method removes the need to prearrange time for a VoIP call. A normal telephone call is established when both parties are ready to connect via the Internet and certain buttons or keys are activated. The systems then proceed to identify one another via a communication method while still connected as a normal telephone call. When this is done, the normal telephone call disconnects and the systems automatically log on to Internet. The dynamic IP address is then obtained from a directory server to establish a VoIP call. A disadvantage of this method is the cost of the required normal telephone call prior to establishing a VoIP call. 
     The “Auto Logon Dedicated Line” method is normally used to bypass the need to incur the cost of a normal telephone call prior to establishing a VoIP call. The system is configured to log on to Internet automatically every time a call is detected on the line and then proceeds to register itself with a directory server. The caller system needs to know the number of the called party and uses this to look up the dynamic IP address from the directory server. A VoIP call is then established. A shortcoming of this method is the fact that a dedicated line needs to be used for VoIP call since all incoming call will be treated as a VoIP call. 
     Hence, there is a need for a method of establishing a VoIP call for dial-up Internet Telephony appliances that notifies the called party to log on to the Internet with minimal interference to the normal usage of the telephone, transparently acquires the address of the called party using a mechanism to translate a unique identifier to IP address so as to not require prior arrangement to log on to Internet at a prearranged time, does not incur PSTN call charges for establishing PSTN-to-PSTN voice call prior to VoIP call, receives normal PSTN telephone calls as well as VoIP calls, and requires minimum technical and new usage knowledge required for a user to make a VoIP call. 
     SUMMARY OF THE INVENTION 
     This new call establishment method for Internet Telephony appliances includes two phases. The first phase is a method of notifying the Internet Telephony appliance of the called party that a VoIP call is being attempted. The second phase is for both systems to automatically log on to the Internet and to proceed through the procedure to establish the VoIP call. The nature of directory server and VoIP protocol is the choice of a particular implementation as this method is independent of any specific directory services or VoIP protocols. The following pseudo-codes and illustrations indicate the steps involved at both the caller&#39;s system (local device) and the called party&#39;s system (remote device) when making a VoIP call. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A shows a diagram of an exemplary local device and remote device of an Internet Telephony system in accordance with a preferred embodiment of the present invention. 
     FIG. 1B shows a diagram of another exemplary local and remote device of the Internet Telephony system in accordance with a preferred embodiment of the present invention. 
     FIG. 1C shows in detail a diagram of the local device computer of FIGS. 1A and 1B. 
     FIG. 1D shows in detail a diagram of the remote device computer of FIGS. 1A and 1B. 
     FIG. 2 is a flowchart of Phase I of the dial-up Internet Telephony method provided by the systems shown in FIG.  1 A and FIG.  1 B. 
     FIG. 3A is a flowchart of Phase II of the dial-up Internet Telephony method provided by the systems shown in FIGS. 1A and 1B. 
     FIG. 3B is a flowchart of the steps performed by the directory server during Phase II of the Internet Telephony method shown in FIG.  3 A. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is of the best presently contemplated mode of carrying out the invention. The description is made for the purpose of illustrating the general principles of the invention and is not to be taken in a limiting sense. 
     For a dial-up Internet telephony appliance, the telephone ring signal is the only indicator that a remote device can use as a notification signal from another party over the PSTN. This new method allows both normal PSTN telephone calls as well as VoIP calls to be used on the same line and equipment. An example VoIP protocol is ITU-T Recommendation H.323 for packet-based multimedia communication systems. The basis of the present invention is to couple the telephone ring signal as an indicator, with some intelligent processing. 
     FIG. 1A shows a diagram of an example local and remote device of an Internet Telephony system in accordance with a preferred embodiment of the present invention. As shown, local device  102  includes a computer  104  connected to modem  106 . Modem  106  is connected to a telephone  108 . 
     Computer  104  may be a PC, APPLE or other type of computing device. FIG. 1C shows in detail exemplary components of computer  104 . Computer  104  will generally include a processor  140  connected to a memory  142 , a computer readable medium device  144  that reads a computer readable medium  146  such as a magnetic disk or CD, an input device  150  such as a keyboard and a display device  152  such as a monitor connected via a bus  148  to local device computer  104 . Memory  142  includes local telephony software  143  for providing telephony processing at computer  104 . Computer  104  in alternative embodiments of the present invention may include more or fewer components. 
     Returning to FIG. 1A, modem  106  is a voice modem capable of simultaneous data and full-duplex voice I/O operations and is dual-tone multi-frequency (DTMF) detection capable. Telephone  108  may be of any generally acceptable conventional telephone device that provides for tone dialing. 
     Similarly, remote device  126  includes a computer  128  connected to modem  124 . Modem  124  is connected to a telephone  130 . 
     As discussed above computer  128  may be a PC, APPLE or other type of computing device. FIG. 1D shows in detail exemplary components of computer  124 . Computer  128  will generally include a processor  154  connected to a memory  156 , a computer readable medium device  158  that reads a computer readable medium  160  such as a magnetic disk or CD, an input device  166  such as a keyboard and a display device  164  such as a monitor connected via a bus  162  to local device computer  128 . Memory  156  includes local telephony software  157  for providing telephony processing at computer  128 . Computer  128  in alternative embodiments of the present invention may include more or fewer components. 
     Returning to FIG. 1A, modem  124  is a voice modem capable of simultaneous data and full-duplex voice I/O operations and is dual-tone multi-frequency (DTMF) detection capable. Telephone  130  may be any generally acceptable conventional telephone device that provides for tone dialing. 
     Local device  102  and remote device  126  may connect to each other via a PSTN  118  and/or VoIP  119  network. As shown modem  106  of local device  102  connects across PSTN  118  to modem  124  of remote device  126 . Modem  106  of local device  102  also connects across the Internet based VoIP  119  network to ISP  112  via dial-up connection  110 . It will be appreciated that alternative embodiments of the present invention may include connections to the ISP that can be an ISDN connection, a cable modem, or any other appropriate connection. ISP  112  connects directly or indirectly to directory server  116  of the VoIP network  119 . Similarly, directory server  116  of VoIP network  119  connects directly or indirectly to ISP  120 . Modem  124  of remote device  126  connects to ISP  120  via connection  122 . Accordingly, there are two alternative methods of connecting local device  102  and remote device  126 . 
     FIG. 1B shows another example of a preferred embodiment of the Internet Telephony system of the present invention. As shown, FIG. 1B replaces local device  102 , computer  104  and modem  106  of FIG. 1A with an Internet Telephony appliance  132 , and replaces remote device  126 , computer  128  and modem  124  with an Internet Telephony appliance  134 . Internet Telephony appliances  132  and  134  include the functionality of respective modems  106  and  124  and the telephony processing of respective computer  104  and  128 . Connections between Internet Telephony appliances are consistent with that of FIG.  1 A. Hence, Internet Telephony appliance  132  is connected to telephone  108  and Internet Telephony appliance  134  is connected to telephone  130 . The PSTN  118  and VoIP network  119  connections are the same as described above with regard to FIG.  1 A. 
     In FIG.  1 A and FIG. 1B a caller (such as a human being) dials, at local device  102 , the remote party at remote device  126  over the PSTN network  118 . Upon hearing the ring-back tone that indicates the remote party telephone  130  is ringing, the caller must drop the PSTN connection within a certain amount of time. Preferably that amount of time is 10 seconds, however, an alternative embodiment may chose a different amount of time that corresponds to the particularities of that embodiment. The actual action of dropping the line could be performed by the caller hanging up the handset or by the local Internet appliance in response to the caller&#39;s pressing a button on the telephone  108  or the device  102 . 
     The caller triggers the event to drop the PSTN connection because of the variety of telephone networks and equipment around the world. Each of these generates different tones for dial tone, ring-back tone, busy tone, and others. Human assistance is preferable in this case to determine the actual tone heard. However, alternative embodiments of the present invention may include local device  102  that is capable of intelligently distinguishing between different tones which enables local device  102  to drop the PSTN connection. A special dialing sequence might also be required to assist the system in determining whether a call being made is a normal telephone call or a VoIP call. 
     FIG. 2 is a flowchart of Phase I of an embodiment of a dial-up Internet Telephony method provided by the systems shown in FIG.  1 A and FIG.  1 B. More particularly, FIG. 2 shows a caller action  202  at local device  102  for establishing a VoIP connection with remote device  126 . 
     The remote Internet Telephony appliance determines the nature of a call, whether it is a normal voice call or a VoIP call, by analyzing the duration of the telephone ring signal. For example, a telephone ring signal for 15 seconds may indicate a normal PSTN call, while a telephone ring signal for 6 seconds may indicate a VoIP call. This example is provided only for illustrative purposes, thus, alternative durations of ring signals may be used to designate the different types of incoming calls. 
     In order to begin the call, in step  204 , the caller presses a key such as ‘#’ to indicate that a VoIP call is being made. When the key is pressed, in step  216 , local device  102  is initialized for the VoIP call. For instance, modem  106  is initialized in FIG. 1A, and Internet Telephony appliance  132  is initialized in FIG.  1 B. In step  206 , the caller dials the phone number of remote device  126  and in step  218  local device  102  captures the dialed number as “REMOTE_ID.” Local device  102  then places the call over PSTN network  118 . In step  224 , remote device  126  detects the call and immediately masks the ringing. The ringing is masked so that the individual receiving the call at remote device  126  is not tempted to pick up the telephone and thereby incur a telephone call charge. 
     When the first ring activity is detected, in step  226 , remote device  126  sets timer t v . Timer t v  is set for a time-out period to allow the PSTN Network time in step  220  to send local device  102  a ring back tone and to allow the caller to detect and respond to the ring back tone in step  208 . The caller, in response to detecting a ring back, in step  210 , presses a # key (or hangs up the handset) hat in step  222  triggers local device  102  to drop the PSTN line. Timer t v  should be set to a value that takes into consideration various factors including delay in the PSTN network, human response time and other factors, and also allow significant margin for error. For example, t v  is preferably set to a time of approximately 10 seconds. However, alternative embodiments depending upon the various factors and particular telecommunications protocol may set t v  to a different time period. 
     There is also a need to minimize interference to the normal usage of the telephone during this period. For example, it is foreseeable that the called party will answer a call if the telephone is ringing. Therefore, as discussed above there is a need to mask off the telephone ringing during the period of t v . This is preferably achieved by including circuitry in the remote Internet Telephony appliance to suppress the ring signal. An alternative method for appliances that can perform ring signal suppression is a concurrent audio or visual alert signal could be generated for the period t v  to remind the called party to ignore the ring signal for that short initial period. The telephone ringing is unmasked in step  229  upon expiration of the timer t v . 
     After the t v period has expired, the remote device continues to monitor PSTN connection  118  for a ring signal for time period t n  to ascertain whether the caller has dropped the connection. The value of t n  should be set to a value that is longer than the total value of the on and off periods of telephone ring cadence. For example, t n  is preferably set to a time of approximately 10 seconds. However, alternative embodiments depending upon the various factors and particular telecommunications protocol may set t n  to a different time period. 
     Any ring activity detected during this period will indicate that this is not a VoIP call (since a VoIP call would have dropped the PSTN line by this time). Hence in step  230 , remote device  126  sets timer t n . In step  232 , the remote device determines if there is ringing activity. If there is ringing activity then in step  240  it is concluded that the call is a normal “PSTN” call and processing returns to the beginning of this telephony method. If ring activity does not occur then in step  234  remote device  126  determines if the telephone is off the hook. If the telephone is off the hook it is concluded in step  240  that an individual at remote device  126  has picked-up the telephone handset for a normal “PSTN” call and therefore processing returns to the beginning of this telephony method. If the telephone is not off-hook then in step  236  remote device  126  determines if t n has expired. If t n  has not expired control then loops back to determine if there is ringing activity, if the telephone is off-hook or if the timer has expired. If t n  has expired then the remote device will determine that the incoming call is a VoIP call and therefore the telephony protocol will continue to Phase  2  as shown in FIG.  3 . In step  214 , after local device  102  drops the PSTN line, control similarly proceeds to the VoIP call in Phase  2  as shown in FIG.  3 . 
     Upon successful completion of the call notification process in Phase I, both remote device  126  and local device  102  will proceed to log on to the Internet. FIG. 3A shows a flowchart of Phase II of the dial-up Internet Telephony method provided by the systems shown in FIGS. 1A and 1B. As shown, in step  302  local device  102  connects to the Internet. In step  304 , local device  102  gets a unique IP address that is dynamically assigned by ISP  112 . In step  306 , local device  102  via ISP  112  connects to directory server  116  and registers the dynamically assigned IP address and a unique identifier of the local device. The unique identifier is preferably the phone number of the local device or a number derived from the phone number. The remote device telephone number is subsequently used as the key for a query to the directory server because it is unique. In addition, both devices know the remote device telephone number because local device  102  captures the number as it is dialed, and remote device  126  is set up with this number. However, alternative embodiments may choose a different scheme for assigning unique identifiers. 
     While local device  102  is logging onto the Internet as described above remote device  126  in step  322  is similarly connecting to the Internet. Remote device  126  in step  324  gets a unique IP address from ISP  120 . In step  326  remote device  126  connects to directory server  116  and registers the IP address and a unique device identifier. As discussed above, this unique device identifier is preferably the remote telephone number. 
     FIG. 3B shows a flowchart of the steps performed by a processor  352  of directory server  116  during Phase II of the Internet Telephony method shown in FIG.  3 A. As shown in step  338 , the initial state of processor  352  of directory server  116  is to wait for a command. If in step  340 , directory server receives a “register” command, such as a request to register an IP address and a unique identifier, then in step  342  processor  352  gets the IP address and a unique identifier from the request. In step  344 , processor  352  stores the IP address and the unique identifier in a database  354 . The address and identifier preferably are stored in database  354  in a conventional database format that allows for ease of data storage and retrieval. Once the data is stored, processor  352  of directory server  116  returns to the state in step  338  of waiting for the next command. 
     If the command in step  340  is not “register” then in step  346  processor  352  determines if the command is a “query.” If the command is a query, then in step  348 , processor  352  gets a unique identifier from the query command. Processor  352  then searches database  354  to locate the corresponding dynamically assigned IP address. Once found, in step  350  processor  352  of directory server  116  returns the IP address to the source of the query. Once the data is retrieved and returned processor  352  of directory server  116  returns to the state in step  338  of waiting for the next command. 
     Returning to FIG. 3A, after local device  102  is registered, in step  308 , local device  102  sets timer t q . The purpose of timer t q  is to establish a time-out period for the local device&#39;s attempt to identify and retrieve the dynamically assigned IP address of remote device  126 . In step  310 , local device  102  begins to query directory server  116  for the remote device IP address using the remote device identifier captured from the dialed number in Phase I. In step  312 , local device  102  determines whether it has received the dynamically assigned IP address of remote device  126 . If the address has not been received then in step  314  timer t q  is checked to determine whether the timer has expired. If t q  expires than the query of step  310  aborts in step  318  and returns in step  320  to the beginning of the process. If the timer has not expired then the query for the remote device&#39;s IP address continues. If in step  312  the IP address of the remote device  126  is found then in step  316  local device  102  proceeds to initiate a VoIP call to the remote IP address of the remote device  126 . 
     The factors that should be considered in determining when to set and for what duration to set timer t q  include the time taken for remote device  126  to log on to the Internet, the time taken for remote device  126  to connect and register with directory server  116  and the timer periods t v and t n . For example, t q  is preferably set to a time of approximately 3 minutes. However, alternative embodiments depending upon the various factors and particular telecommunications protocol may set t q  to a different time period. 
     While local device  102  attempts to send a VoIP call, remote device  126  after successfully connecting and registering with directory server  116  in steps  322 - 326 , monitors for incoming calls. Hence, in step  328  remote device  126  sets time t w  to establish a time-out period for monitoring for an incoming VoIP call. For example, t w  is preferably set to a time of approximately 3 minutes. However, alternative embodiments depending upon the various factors and particular telecommunications protocol may set t w  to a different time period. If a VoIP call is not received during the time-out period set in timer t w , the process is aborted. The time-out period could occur due to a number of reasons. For example, local device  102  may be unable to log on to the Internet. Further, local device  102  may be unable to retrieve the remote device IP. Still further, an invalid remote identifier may have been used by local device  102  for the query operation. In addition, it is possible that an accidental call satisfied the call notification process of Phase I, but that the call originated from an incompatible Internet Telephony device. 
     In step  330 , remote device  126  continues to monitor whether it has received a VoIP call from local device  102 . If not then remote device  126  determines if timer t w  expired. If timer t w  has expired then the process in step  318  aborts and returns in step  320  to the beginning of this process. If timer t w  has not expired then remote device again monitors whether it has received a VoIP call from local device  102 . If remote device  126  detects the incoming VoIP call from local device  102  in step  330  then in step  334  remote device  126  is alerted and then proceeds to answer the VoIP call. 
     In summary, call notification involves two distinct operations at the local and remote device. Each device can either be a local or remote device depending on the event that triggers it. Table 1 shows a procedure to determine whether a device is local or remote. Table 2 and 3 show a procedure in both local and remote devices, respectively. Tables 4 and 5 show a procedure for Phase II of establishing a VoIP call between local and remote devices. 
     
       
         
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Pseudo-code for Phase I of Call Notification Process 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 PhaseI_start: 
               
               
                   
                 ;wait for telephone to go off-hook or ring 
               
             
          
           
               
                   
                 if telephone off-hook then 
               
             
          
           
               
                   
                 goto phaseI_local 
               
             
          
           
               
                   
                 if telephone ring then 
               
             
          
           
               
                   
                 goto phaseI_remote 
               
             
          
           
               
                   
                 goto phaseI_start 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
             
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Pseudo-code for Phase I of Local Device Process 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 phaseI_local: 
               
             
          
           
               
                   
                 ; check for initial ‘#’ to indicate a VoIP call being made 
               
               
                   
                 if telephone on-hook then 
               
             
          
           
               
                   
                 goto phaseI_start 
               
             
          
           
               
                   
                 get DTMF_TONE 
               
               
                   
                 if DTMF_TONE &lt;&gt; ‘#’ then 
               
             
          
           
               
                   
                 goto phaseI_start 
               
             
          
           
               
                   
                 ; capture all dialed number until second ‘#’ is encountered 
               
               
                   
                 REMOTE_ID = NULL 
               
               
                   
                 repeat 
               
             
          
           
               
                   
                 ; restart if telephone goes on-hook 
               
               
                   
                 if telephone on-hook then 
               
             
          
           
               
                   
                 goto phaseI_start 
               
             
          
           
               
                   
                 get DTMF_TONE 
               
               
                   
                 if DTMF_TONE &lt;&gt; ‘#’ then 
               
             
          
           
               
                   
                 REMOTE_ID = REMOTE_ID + DTMF_TONE 
               
             
          
           
               
                   
                 until DTMF_TONE = = ‘#’ 
               
               
                   
                 ; VoIP call is confirm, proceed to next phase 
               
               
                   
                 drop PSTN call 
               
               
                   
                 goto phaseII_local 
               
             
          
           
               
                 NOTE: 
               
             
          
           
               
                   
                 REMOTE_ID is the remote party telephone number which will 
               
               
                   
                 be used as unique ID for directory server lookup in Phase II 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                 Pseudo-code for Phase I of Remote Device Process 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 phaseI_remote: 
               
             
          
           
               
                   
                 ; mask off telephone ring for initial period of tv 
               
               
                   
                 setup timer t v   
               
               
                   
                 mask telephone ring 
               
               
                   
                 wait for t v  expire 
               
               
                   
                 unmask telephone ring 
               
               
                   
                 ; check if this is a normal voice call 
               
               
                   
                 setup timer t n   
               
               
                   
                 repeat 
               
             
          
           
               
                   
                 if telephone ring then 
               
             
          
           
               
                   
                 goto normal_call 
               
             
          
           
               
                   
                 if telephone off-hook then 
               
             
          
           
               
                   
                 goto phaseI_start 
               
             
          
           
               
                   
                 until t n  expire 
               
               
                   
                 ; VoIP attempt is detected, proceed to next phase 
               
               
                   
                 goto phaseII_remote 
               
               
                   
                 ; normal voice call detected, wait until no more ring or call 
               
               
                   
                 ; is answered by remote party 
               
               
                   
                 normal_call: 
               
             
          
           
               
                   
                 setup timer t r   
               
               
                   
                 repeat 
               
             
          
           
               
                   
                 if telephone ring then 
               
             
          
           
               
                   
                 setup timer t r   
               
             
          
           
               
                   
                 if telephone off-hook then 
               
             
          
           
               
                   
                 goto phaseI_start 
               
             
          
           
               
                   
                 until t r  expired 
               
               
                   
                 goto phaseI_start 
               
             
          
           
               
                   
                 NOTE: 
               
             
          
           
               
                   
                 t v   
                 : 
                 time-out period for caller to confirm a VoIP call 
               
               
                   
                 t n   
                 : 
                 time-out period for detection of normal call 
               
               
                   
                 t r   
                 : 
                 time-out period for detection of ring completion 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
             
               
               
             
               
               
             
               
               
             
               
             
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                 Pseudo-code for Phase II of Local Device Process 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 phaseII_local: 
               
               
                 ;log on to Internet and get local IP address 
               
               
                 log on to Internet 
               
               
                 LOCAL_IP = IP address assigned by ISP 
               
               
                 LOCAL_ID = telephone number of local device PSTN line 
               
               
                 ;register locaL device with directory server 
               
               
                 connect to directory server 
               
               
                 register_IP (LOCAL_ID, LOCAL_IP) with directory server 
               
               
                 ;look up IP address of remote device using REMOTE_ID 
               
               
                 setup timer t q   
               
               
                 repeat 
               
             
          
           
               
                   
                 REMOTE_IP = query_IP (REMOTE_ID) from directory server 
               
               
                   
                 ;if IP address of remote device is received successfully 
               
               
                   
                 ;initiate VoIP call with REMOTE_IP 
               
               
                   
                 if query_IP successful then 
               
             
          
           
               
                   
                 goto VoIP_call (REMOTE_IP) 
               
             
          
           
               
                   
                 until t q  expire 
               
               
                   
                 ;time-out and call is aborted 
               
               
                   
                 goto phaseI_start 
               
             
          
           
               
                 NOTE: 
               
             
          
           
               
                   
                 t q  is the time-out period for attempts to query for remote IP address 
               
               
                   
                 REMOTE_ID is the remote party telephone number which was 
               
               
                   
                 captured in Phase I 
               
               
                   
                 REMOTE_IP is the remote IP address that is returned by a 
               
               
                   
                 successful query to the directory server 
               
               
                   
                 VoIP_call is a generic procedure to initiate a protocol specific 
               
               
                   
                 VoIP call with the IP address specified 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
             
               
               
             
               
               
             
               
               
             
               
               
             
               
             
               
               
             
           
               
                 TABLE 5 
               
               
                   
               
               
                 Pseudo-code for Phase II of Remote Device Process 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 phase II_remote: 
               
             
          
           
               
                   
                 ; log on to Internet and get remote IP address 
               
               
                   
                 log on to Internet 
               
               
                   
                 REMOTE_IP = IP address assigned by ISP 
               
               
                   
                 REMOTE_ID = telephone number of local device PSTN line 
               
               
                   
                 ; register remote device with directory server 
               
               
                   
                 connect to directory server 
               
               
                   
                 register_IP (REMOTE_ID, REMOTE_IP) with directory server 
               
               
                   
                 ; wait for call from caller device for a period of t w   
               
               
                   
                 setup timer t w   
               
               
                   
                 repeat 
               
             
          
           
               
                   
                 if VoIP_callalert is true then 
               
             
          
           
               
                   
                 gotoVoIP_answer 
               
             
          
           
               
                   
                 until t w  expire 
               
               
                   
                 ; time-out and call is aborted 
               
               
                   
                 goto phaseI_start 
               
             
          
           
               
                 NOTE: 
               
             
          
           
               
                   
                 t w  is the time-out period for waiting for the caller device to attempt 
               
               
                   
                 a VoIP call 
               
               
                   
                 VoIP_callalert is a generic procedure that return the status of 
               
               
                   
                 whether a VoIP call alert signal is being received 
               
               
                   
                 VoIP_answer is a generic procedure to answer a VoIP call 
               
               
                   
                   
               
             
          
         
       
     
     It can therefore be appreciated that a new and novel Internet Telephony connection method has been described. It will be appreciated by those skilled in the art that, given the teaching herein, numerous alternatives and equivalents will be seen to exist which incorporate the invention disclosed hereby. As a result, the invention is not to be limited by the foregoing exemplary embodiments, but only by the following claims and equivalents thereof.