Abstract:
Digits dialed using a pulse dialing device, such as a rotary phone or pulse-based alarm system, are detected by an MTA device that has been configured using an MIB object in the MTA configuration file. Upon detection the MTA generates a DTMF signal, or RFC2833 digit event, and forwards the DTMF signal or RFC2833 digit event corresponding to the dialed digit toward a communication network.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority under 35 U.S.C. 119(e) to U.S. provisional patent application No. 60/666,347 entitled “Dialing method conversions in a PacketCable-defined CPE device”, which was filed Mar. 30, 2005, and is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to broadband communication, and more particularly to a method converting pulse dial signals to tone dial signals.  
       BACKGROUND  
       [0003]     Community antenna television (“CATV”) networks have been used for more then four decades to deliver television programming to a large number of subscribers. Increasingly, CATV networks are used by providers to provide data services to subscribers. For example, cable modems used in a broadband cable modem termination system (“CMTS”) are capable of transmitting and receiving Internet data using the Data Over Cable Service Interface Specification (“DOCSIS”) protocol. DOCSIS provides a standard that allows network devices made by different vendors to communication with one another.  
         [0004]     Similar to DOCSIS, which is administered by Cable Television Laboratories, Inc. (CableLabs®), “PacketCable™ is a CableLabs-led initiative aimed at developing interoperable interface specifications for delivering advanced, real-time multimedia services over two-way cable plant. Built on top of the industry&#39;s highly successful cable modem infrastructure, PacketCable networks use Internet protocol (IP) technology to enable a wide range of multimedia services, such as IP telephony, multimedia conferencing, interactive gaming, and general multimedia applications.” See www.packetcable.com. DOCSIS and PacketCable are protocol standards known in the art and do not require further discussion of the basic functioning thereof. However, it will be appreciated that, although DOCSIS and PacketCable are currently considered industry standards, other protocol standards may become predominant over time. Thus, for purposes of discussion herein, DOCSIS may be generically referred to as a ‘data protocol’ and PacketCable as a ‘multimedia protocol.’ 
         [0005]     As with many other technologies, consumer subscriptions to telephony services that are provided over a network other than the public switched telephony network (“PSTN”) are increasing. However, some consumers may not want to purchase new telephone handsets, although they may otherwise wish to subscribe to telephony over cable service, PacketCable, for example. In some of these cases, the consumers&#39; telephone sets may not be capable of tone dialing, or dual tone multi frequency (“DTMF”) dialing. Equipment not capable of DTMF dialing is typically referred to as pulse dialing equipment, and example of which may include a telephone set having a rotary dial for a user to input digits when dialing another telephone number. Another example of such equipment is a pulse dialing enabled alarm system board.  
         [0006]     In currently available implementations, detected pulse dialed digits are not communicated directly to the telephony switch, such as a class 5 telephony switch. The RFC2833 protocol may be used to communicate each on/off hook transition to the PSTN gateway. The PSTN gateway then reproduces the on-hook, off-hook transitions toward the Class 5 switch. The class 5 switch then interprets the pulses in real time to determine the dialed digits. Latency, jitter and packet loss introduced by the network can negatively affect the relative timing of each pulse and thus render digit detection very difficult. These factors make this approach impracticable due to the strict timing requirements of pulse dialing.  
         [0007]     Another approach has been to have the Multimedia Terminal Adaptor (“MTA”) interpret the pulse dialed digits, relay the information via NCS to a signaling (such as PSTN) gateway device, and then have the gateway device communicate the dialed digits to the Class 5 switch. However, this approach not only introduces delay with each dialed digit, but is also problematic because there is no specified mechanism for the gateway to communicate dialed digits directly to the Class 5 switch.  
         [0008]     Thus, there is a need in the art for a method and system for providing pulse dialing support for telephony services over networks other than the PSTN.  
       SUMMARY  
       [0009]     A method for converting dialed digit pulse signals into tone digit signals includes having an MTA detect the pulse dialed digits, and then generate DTMF tones. These generated tones are relayed directly to the telephony switch by in-band signaling. This DTMF in-band tone relay feature not only alleviates delay conditions introduced by the other options, but also allows a call management server (“CMS”), PSTN gateway and switch to operate as if the dialing device is generating DTMF tones. Furthermore, if the CMS enables RFC2833 Digit Events on the MTA, the pulse dialed digits can be converted to RFC2833 events and relayed in-band towards the network for increased reliability. This invention also allows operators to charge their subscribers a differential service fee to enable pulse dialing devices. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  illustrates a network configuration with a PSTN Gateway.  
         [0011]      FIG. 2  illustrates a network configuration with a CMS.  
         [0012]      FIG. 3  illustrates a flow diagram of a method for placing calls using pulse dial equipment and in-band signaling over a network with a signaling gateway.  
         [0013]      FIG. 4  illustrates a flow diagram of a method for placing calls using pulse dial equipment and RFC2833 messages over a network with a signaling gateway. 
     
    
     DETAILED DESCRIPTION  
       [0014]     As a preliminary matter, it will be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many methods, embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the following description thereof, without departing from the substance or scope of the present invention.  
         [0015]     Accordingly, while the present invention has been described herein in detail in relation to preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purposes of providing a full and enabling disclosure of the invention. This disclosure is not intended nor is to be construed to limit the present invention or otherwise to exclude other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.  
         [0016]     Turning now to the figures,  FIG. 1  illustrates a network system  100  for providing Voice over an IP network (“VoIP”). During a call initiation sequence, a call is placed when terminal device  125 , such as a dial-pulse telephone, goes off-hook. MTA  120  detects the off-hook and notifies IPDT Signaling gateway  115 . Gateway  115  then notifies the Class 5 Telephony switch  110 . Switch  110  then sends dial tone down to MTA  120  and prepares to accept DTMF addressing information from MTA  120 . Once the switch has received and decoded the DTMF addressing information, the call is put through.  
         [0017]      FIG. 2  illustrates another network system configuration  200  for a Vo IP network. During a call initiation sequence, a call is placed when terminal device  225  goes off-hook. MTA A  220  detects the off-hook and notifies Call management Server (“CMS”)  215 . CMS  215  then sends a message that requests that MTA A  220  send dial tone and collect the dialed digits from terminal device  225 . After MTA  220  has collected the required addressing information it sends a message to CMS  215  with the addressing information. CMS  215  decodes the addressing information and potentially directs MTA  220  to connect to another MTA, such as MTA B  230 , or CMS  215  can connect the call through trunking gateway  205 , or through gateway  210 .  
         [0018]     Turning now to  FIG. 3 , a flow diagram of a method  300  for placing calls using pulse dial equipment over a tone dialing network is illustrated. Method  300  starts at step  305  when a user attempts to place a telephone call to a device associated with another telephone number by dialing a digit of the telephone number to be called. If the user is a subscriber to telephony services over cable, such as PacketCable, for example, the user device typically comprises an MTA. At step  310  the MTA receives the dialed digit signal pulse. The MTA detects that the incoming signal is a pulsed digit signal at step  315  by analyzing the incoming pulse signal according to known methods. Based on the number of pulses in a single digit pulse-signal, a corresponding tone signal is generated based on a mapping of tone signal frequency(ies) to number of pulses. Such techniques are known in the art.  
         [0019]     The MTA generates a DTMF tone signal corresponding to the dialed digit at step  320  and sends it to the PSTN gateway at step  325  within the voice band, often referred to in the art as ‘in-band’. The dialed digits are sent in-band so the switch and call processing devices in the network need not be modified to accommodate the user with a pulse dial device. The process ends at step  330 .  
         [0020]     It will be appreciated that the DTMF tones are transmitted to the PSTN gateway via the RTP connection or stream. The tone frequencies, level and duration of the DTMF tones are all within Telcordia specifications for DTMF digit generation and will thus be detected as such by any compliant DTMF detector (such as that on a Class 5 switch). This will enable the switch to process dialed digits as if the dialed digit(s) originated from a DTMF device. Since the switch will be receiving DTMF digits instead of pulse dialing information, it should be configured as such. This aspect of the invention is typically not applied in CMS controlled (i.e. non-IPDT) solutions. In such a configuration, dialed digits are notified to the CMS. Therefore, there is no need to also relay them in-band.  
         [0021]     It is noted that RFC2833 may also be used to relay digit information to the far end if requested by the CMS. As long as pulse dialing is enabled, a pulse dialed digit may be relayed using RFC2833 when requested, as is currently done with DTMF dialed digits. The steps shown in the flow diagram illustrated in  FIG. 4  are similar to corresponding steps in  FIG. 3 , with the exception of step  420  of  FIG. 4  as compared to step  320  from  FIG. 3 . As described above, at step  320 , a detected digit is used to generate an equivalent DTMF digit tone signal before sending toward the network at step  325 . In  FIG. 4 , a detected dialed digit is used to assemble a RFC2833 message corresponding to the dialed digit at step  420  before the RFC2833 message is forwarded toward the network at step  425 . It will be appreciated that the network toward which either a DTMF signal or a RFC2833, as described above in reference to  FIGS. 3 and 4  respectively, may be either a PSTN network or a VoIP network.  
         [0022]     An MTA at a customer premise may support multiple scenarios as listed in the following table.  
                             TABLE 1                           Potential MTA Dialing Settings            Scenario   Dialing Method   Description               1   Tone   Enables DTMF tone               detection only.       2   Pulse   Enables pulse dialing               detection only.       3   Tone &amp; Pulse   Enables both DTMF               tone and pulse dialing               detection.       4   Pulse w/DTMF Relay   Enables pulse dialing               detection with DTMF               in-band relay enabled.       5   Tone &amp; Pulse w/DTMF   Enables both DTMF           Relay   tone and pulse dialing               detection with DTMF               in-band relay enabled.                  
 
         [0023]     These and many other objects and advantages will be readily apparent to one skilled in the art from the foregoing specification when read in conjunction with the appended drawings. It is to be understood that the embodiments herein illustrated are examples only, and that the scope of the invention is to be defined solely by the claims when accorded a full range of equivalents.