Abstract:
The claimed invention consists of integrating a wireless client with a network adapter in a single device which allows a telephone to connect to a network access point for the purpose of establishing Voice-over-IP (VoIP) calls. The user can attach his telephone to the network adapter and place it anywhere within range of a wireless network and not be required to connect to a wired network via a cable. This allows the end user to place the network adapter and phone in a place without the restrictions of wires. Also, the network adapter could be used to transmit voice data over a broadband link and to transmit emergency calls over a cellular network. In a further embodiment of the invention, various elements of the emergency call re-routing functionality may be placed at various points in a telephone system, for example, in a telephone, a specialized adapter or a conventional personal computer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims priority to and is a continuation-in-part of U.S. application Ser. No. 11/369,124, filed Mar. 7, 2006, under 35 U.S.C. §120, which is a continuation in part of U.S. application Ser. No. 11/353,958, filed Feb. 15, 2006, under 35 U.S.C. §120, the contents of which are hereby incorporated in their entirety by reference, in accordance with C.F.R. 1.53(b)(2). 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention is applicable at least in the field of data communications (e.g., those that implement Voice over Internet Protocol (VoIP) communications) and the field of cellular telephony and, more particularly, in the field of devices, systems, processor program products, and methods of facilitating emergency calls. The invention may be applicable, for example, in systems interfacing a standard telephone to a data network (e.g., a VoIP compatible communication network) via, for example, a computer system, which may facilitate communication over the data network via, for example, a local area network, wide area network, and/or over an existing wireless network.  
       BACKGROUND OF THE INVENTION  
       [0003]     VoIP is a technology that allows the systems and transmission channels that connect computer networks to act as an alternative to phone lines, delivering real-time voice to both standard telephones and personal computers (PCs). VoIP allows an individual to utilize a network connection to transmit voice encapsulated data packets over available local communication lines, such as the Internet. This is typically facilitated by the use of an Analog Telephone Adapter (ATA) which emulates some functions of a phone company&#39;s central office and connects via a wired interface to a network like the Internet.  
         [0004]     In a VoIP system, the analog voice signal is typically picked up by a microphone and sent to an audio processor within a personal computer. In the computer, either a software or hardware CODEC performs analog-to-digital conversion and compression. Considerable research has been devoted to voice compression schemes that are well know to those skilled in the art. The nominal bandwidth required for telephone-type voice ranges from 2.9 Kbps (RT24 by Voxware) to 13 Kbps (GSM cellular standard).  
         [0005]     In placing the CODEC output into packets, there is a trade-off between bandwidth and latency. CODECs do not operate continuously. Instead, they sample the voice over a short period of time, known as a frame. These frames are like little bursts of data. One or more frames can be placed in a single IP datagram or packet, and then the packet payload is wrapped in the necessary packet headers and trailers. This packet overhead is at least 20 bytes for IP and 8 bytes for the User Datagram Protocol (UDP). Layer  2  protocols add even more overhead. Waiting longer to fill the IP datagram reduces overall overhead, which in turn reduces the true bandwidth needed to send the digitized voice. However, this waiting creates latency at the source, and too much total latency makes for a difficult conversation.  
         [0006]     The total network latency and jitter (changes in the latency) have a degrading effect upon voice quality. Therefore, real-time voice quality is difficult to maintain over a large wide-area packet network without priority handling. As previously mentioned, VoIP converts standard telephone voice signals into compressed data packets that can be sent locally over an Ethernet or globally via an ISP&#39;s data networks rather than traditional phone lines. One of the main difficulties with VoIP connections is that the communication network supporting a VoIP platform must be able to recognize that VoIP data packets contain voice signals, and be “smart” enough to know that the communication network has to move the data packets quickly.  
         [0007]     Presently, most VoIP voice traffic does not use the public Internet but runs on private IP-based global networks that can deliver voice data with minimal congestion. As such, transmission of voice signals over private data networks offers businesses some great advantages. For ISPs, merging voice and data on one single network allows them to expand their services beyond simple information access and into the realm of voice, fax, and virtual private networking. For businesses, the benefit is big savings on long-distance service. The Internet right now is a free medium on many networks. If businesses can send voice over a computer network, businesses can conceivably make long-distance or international calls for the cost of a local call. VoIP further facilitates electronic commerce by allowing a customer service representative using one data line to answer telephone questions while simultaneously placing a customer&#39;s order online, perusing the company&#39;s web site, browsing an online information/product database, or sending an E-mail. Similarly, VoIP also creates new possibilities for remote workers, who for the cost of a local call can log in remotely, retrieve voice mail from their laptop PCs, and keep their E-mail and web applications running while conducting multiple voice and data calls over one phone line. Presently, this type of expanded VoIP functionality is exclusively limited to those with access to private IP based networks, such as business users and not the typical household user.  
         [0008]     In fact, most household computer users are generally limited to the congested public Internet and cannot implement the VoIP standard effectively. If latency and jitter are too high, or the cost of reducing them is excessive, one alternative is to buffer the CODEC data at the receiver. A large buffer can be filled irregularly but emptied at a uniform rate. This permits good quality reproduction of voice. Such a buffering technique is known as audio streaming, and it is a very practical approach for recorded voice or audio. Unfortunately, excessive buffering of the audio signals leads to generally unacceptable one-sided telephone conversations, where one party dominates the transmissions.  
         [0009]     Traditionally, the operating environment for a household user with a VoIP connection is either a laptop or desktop general-purpose computer. The recording and transmission or interpretation of the VoIP packets takes place in the sound system or modem DSP found on the laptop or desktop. As such, the desktop system has a minor advantage over the laptop, because the desktop sound system traditionally provides stereo surround speakers and an accurate microphone. Thus, the desktop system can more accurately capture an individual&#39;s voice for retransmission of these voice signals to the user on the other end of the connection. VoIP telephone software buffering and control structures help improve the connection, but even though the audio signal has been accurately sampled, the processor delays and transmission latency associated with the desktop VoIP connection over the public Internet tends to result in a barely audible VoIP call. One of the main difficulties with using VoIP is that it is difficult to facilitate the handling of emergency calls, e.g., emergency “911” calls via systems that implement a VoIP connection. This is especially true when VoIP connections are initiated from mobile or nomadic devices. Another difficulty that is reflected in a household system is that the ATA has to be connected to the network access device via a wired connection and thus limits the placement of the phone.  
         [0010]     The present invention solves these and other problems involved in the current state of the art, as will be explained below.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention is best understood with reference to the claims, the entire specification and all of the drawings submitted herewith, which describe the devices, systems, processor program products and methods of the present invention in greater detail than this summary, which is merely intended to convey aspects of illustrative embodiments of the present invention. By way of example, the disclosed devices (e.g., computers and network adapters), systems, processor program products and methods may include a combination of hardware and/or software which allows the user to overcome problems associated with making emergency calls on a VoIP communications network. By way of example, the central processing unit(s), processor(s), controller(s) or control logic in the disclosed devices (e.g., the computers and network adapters) can include the ability to route, via a transceiver for example, emergency calls to a commercial mobile radio service (“CMRS” or cellular) transmitter over a CMRS network to facilitate the handling of emergency calls, such as emergency “911” calls.  
         [0012]     The systems and methods disclosed herein also solve the other problems alluded to above by allowing the devices (e.g., the computers and network adapters) to connect to a wireless network and thereby to a VoIP carrier via a signaling protocol. The limitations of the prior art are thus overcome and additional freedom and functionality are provided the user, as described in more detail below.  
         [0013]     Optionally, the network adapter can also be configured to transmit information over a broadband cellular link, such as EV-DO or other similar types of networks.  
         [0014]     Additional objects, advantages and novel features of this invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practicing the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     In the accompanying drawings that form a part of the specification and are to be read in conjunction therewith, the present invention is illustrated by way of example and not limitation, with like reference numerals referring to like elements, wherein:  
         [0016]      FIG. 1  illustrates a network adapter, according to an embodiment of the invention;  
         [0017]      FIG. 2 ( a ) illustrates a communications network, according to an embodiment of the invention;  
         [0018]      FIG. 2 ( b ) illustrates a communications network, according to another embodiment of the invention;  
         [0019]      FIG. 3 ( a ) is a flow chart illustrating the process of making an out-bound call, according to an embodiment of the invention;  
         [0020]      FIG. 3 ( b ) is a continuation of a flow chart illustrating the process of making an out-bound call, according to an embodiment of the invention;  
         [0021]      FIG. 4  is a flow chart illustrating the conclusion of a VoIP voice call, according to an embodiment of the invention;  
         [0022]      FIG. 5  is a flow chart illustrating the beginning of a VoIP voice call, according to an embodiment of the invention;  
         [0023]      FIG. 6  is a flow chart illustrating the beginning of a PSTN voice call, according to an embodiment of the invention;  
         [0024]      FIG. 7  is a flow chart illustrating the process of making an emergency call, according to an embodiment of the invention;  
         [0025]      FIG. 8  illustrates a communications network, according to an embodiment of the invention;  
         [0026]      FIG. 9  is a flow chart illustrating the process of making an emergency call, according to another embodiment of the invention;  
         [0027]      FIG. 10  illustrates a computer system, according to another embodiment of the invention; and  
         [0028]      FIG. 11  is a flow chart illustrating the process of making an emergency call, according to another embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. In other instances, well known structures, interfaces, and processes have not been shown in detail in order not to unneccessarily obscure the invention. However, it will be apparent to one of ordinary skill in the art that those specific details disclosed herein need not be used to practice the invention and do not represent a limitation on the scope of the invention, except as recited in the claims. It is intended that no part of this specification be construed to effect a disavowal of any part of the full scope of the invention.  
         [0030]      FIG. 1  illustrates the components of a particular device, which is a network adapter  100 , according to an embodiment of the invention. However, these components may be employed in a number of other systems and devices of the present invention. By way of the example, the components described in connection with the network adapter  100  and the manner in which they are employed may be the same for other devices, including telephones (e.g., cellular phones) and computers. Accordingly, the description of the network adapter  100  set forth herein and reflected in the drawings may be read more broadly as merely an example of the types of features that other devices, such as telephones and computers, may have that implement the present invention.  
         [0031]     The network adapter  100  includes a central processing unit  135  connected to the relay  160  via the SLIC  140  and the DAA  145 . The relay  160  is used to isolate and bridge an analog telephone handset ( 165 ) to a public switched telephone network (PSTN).  
         [0032]     As stated above, the network adapter  100  includes a subscriber line interface (SLIC)  140  and a data access arrangement (DAA) circuit  145 . The SLIC  140  is responsible for emulating a central office. It generates a ring current, detects on-hook and off-hook transition and notifies the central processing unit (CPU)  135  of any signal transition. The SLIC  140  also performs A/D conversion on input voice signal and D/A conversion on voice signal to be processed by the telephone handset ( 165 ). The DAA  145  detects a ring current and notifies the CPU  135  of the presence of a ring current. The DAA  145  also creates off-hook and on-hook transactions in order to emulate a telephone handset back to the phone company&#39;s central office, and it also performs A/D and D/A conversion on signals transmitting to and from the central office (not shown).  
         [0033]     The CPU  135  controls the network adapter  100  via programmable software. The CPU  135  is a microprocessor, of a kind that is well known to one of ordinary skill in the art. Integrated into the CPU  135  is a digital signal processor software (not shown) which processes voice signal data in real time.  
         [0034]     Connected to the CPU  135  are several memory devices, flash memory  110  and SDRAM  115 . The flash memory  110  is used as a working storage for the CPU  135  during operation. The SDRAM  115  is used to store information permanently, such as configuration information and program code, when the network adapter  100  is turned off.  
         [0035]     The MPEG-4/H.264 decoder  120  is an integrated circuit that is responsible for producing video output from the CPU  135  to the LCD Display  105 . The MPEG-4/H.264 decoder  120  decodes streaming video information received via the wide area network connection  155  via the CPU  135 . One of ordinary skill in the art can appreciate that any kind of MPEG-4/H.264 decoder can used to decode the video output.  
         [0036]     The LCD Display  105  is used to display information about the incoming call and diagnostic and status information of the network adapter  100 . The LCD Display  105  can also be used to display and present advertising and entertainment to the user. In an alternative embodiment of the invention, the CPU  135  includes circuity which monitors the signal strength of the wireless network (not shown) employed by the network adapter  100 . The signal strength monitoring circuity is well known to one of ordinary skill in the art. The MPEG-4/H.264 decoder  120  receives this information from the CPU  135  in real-time and transfers this information to the LCD Display  105 . The LCD Display  105  receives the signal strength information and displays it to the user in a known manner. Accordingly, the user can monitor the signal strength as displayed on the LCD Display  105  to manually adjust the location of the network interface  100  in order to maximize the signal strength.  
         [0037]     A wireless network card  125  is connected to the CPU  135 . The wireless network card  125  is connected to the CPU  135  via a mini-PCI connector (not shown). The wireless network card  125  allows the network adapter  100  to access any one of available wireless networks. The wireless network card can transmit the information to the network by implementing a variation of the IEEE 802.11 standard, however, one of ordinary skill can appreciate that other methods can be employed as well. The wireless network card  125  is built into the network adapter via a replaceable module via a known standard such as PCI, PCMIA or USB. By employing a particular wireless card, a user can have access to any number of wireless networks such as Wi-Fi, Wi-Max, EV-DO, HSPDA and any other wireless network for which a mini-PCI card has been developed.  
         [0038]     One of ordinary skill in the art can appreciate that the network adapter  100  requires AC or DC power in order to operate. As way of example and not limitation, the network adapter can be powered from an AC electrical outlet or DC power source, such as the cigarette lighter in an automobile or a DC battery.  
         [0039]     In yet another embodiment of the invention, the network adapter  100  can be adapted to include multiple wireless network cards. The multiple wireless network cards feature would allow the user flexiblity to employ different types of wireless network services, such as Wi-Fi and cellular broadband wireless. One of ordinary skill can appreciate that many different services can be employed and the example is used for illustration and not as a way of limitation. The circuitry would be adapted to include a mini-PCI card and another mini-PCI card or other replaceable module, such as PCMIA, USB or PCI. The CPU  135  would include software which would allow the network interface to adaptively switch between using the wireless network cards to transmit a voice signal and allow a user to replace wireless network cards during the operation of the network adapter  100 . For example, when the network adapter  100  is not in range of the router  235  via Wi-Fi or other wireless network, the network adapter  100  would transmit the packetized voice signal from the phone via a broadband cellular network like EV-DO or other applicable cellular broadband network to which the user has a subscription.  
         [0040]     The network adapter  100  has the capability to be attached to a local area network  150  to communicate with users on laptop or desktop personal computers and a wide area/broadband network  155  for communicating over a packet switched network, such as the Internet. Typically, the network adapter has one or more RJ-11 jacks to connect with a telephone, and at least one RJ-45 connection to a 10/100BaseT Ethernet Hub or switch to connect to the local area network  150 .  
         [0041]     Also, connected to the CPU  135  is a cellular chip  130  implementing a transceiver which allows the network adapter  100  to access a cellular network. The cellular chip  130  receives voice data from the CPU and modulates and transmits the data in a known way as to communicate with another user on the celluar network. The cellular chip  130  functions in a duplex manner as to allow voice conversations over the cellular network. In an embodiment of the invention, the CPU  135  may execute software that routes emergency calls to the cellular chip which establishes a two-way communication channel corresponding to the emergency call, the two-way communication channel being established over a cellular network.  
         [0042]      FIG. 2 ( a ) illustrates a communications network  200 , according to an embodiment of the invention. The communications network  200  includes a telephone  205 , cellular network  210 , network adapter  100 , local area network (LAN)  220 , laptop computer  225 , personal computer  230 , router  235 , a broadband modem  240 , Internet  245 , end-user  250 , and public safety answering point (PSAP)  255 .  
         [0043]     According to an embodiment of the invention, the network adapter  100  includes a wireless network card  125  which allows the analog phone adapter  100  to wirelessly connect to a wide area network, such as the Internet  245 . As shown in  FIG. 2 , the network adapter  100  would transmit digitized voice signals to a router  235 . The router  235  is of a kind well known by those of ordinary skill in the art, such as 802.11g routers. The router  235  would receive the voice signal and convert it into a packet format for transmission over the Internet  245 . Accordingly, the network adapter  100  need not be physically connected to the router  235  and therefore does not have to be in close physical proximity to the router  235 .  
         [0044]     The network adapter can receive voice inputs from a telephone  205 , or from a laptop computer  225  or personal computer  230  via a LAN  220 .  
         [0045]     As stated above and with reference to  FIG. 1 , the network adapter  100  includes a wireless network card  125 . The wireless network card  125  is of a kind known to one of ordinary skill in the art, such 802.11b and 802.11g PCI cards. The wireless network card  125  in the network adapter  100  can be configured to transmit the digitized voice data across several different networks. One of ordinary skill in the art can appreciate that there are numerous types of wireless PCI cards allowing access to numerous networks, such as Wi-Fi, Wi-Max, EV-DO and HSPDA and others.  
         [0046]     The router  235  transmits the digitized voice signal to the broadband modem  240 . Devices such as routers act as access points, or portals, to a packet switched network, such as the Internet. The broadband modem  240  encodes and transmits the digitized voice signal across a packet switched network such as the Internet  245 . The broadband modem  240  can be cable modem, DSL modem, or satellite or other wireless broadband link. One of ordinary skill in the art can appreciate that the router  235  could be a stand-alone router for a home user or a server in an enterprise setting.  
         [0047]     The transmitted digitized voice signals are received and decoded and converted to analog voice signals by end user  250  at the far-end.  
         [0048]     The network adapter  100  also includes a cellular chip  130  which is used for diverting emergency 911 calls from the VoIP system. When the network adapter  100  detects an emergency call, the CPU  135  diverts the call to the cellular chip  130  for transmission over a cellular network (not shown). The PSAP  255  receives the call and processes the call.  
         [0049]     The embodiment shown in  FIG. 2  is provided for illustration purposes and not by way of limitation. It will be apparent to one of ordinary skill in the art that the elements that make up the communications network can vary and be optimized for different applications.  
         [0050]      FIG. 2 ( b ) illustrates a communications network  201 , according to an embodiment of the invention. The communications network  201  includes a telephone  205 , network adapter  100 , local area network (LAN)  220 , laptop computer  225 , personal computer  230 , broadband cellular link  265  and end-user  250 . According to one embodiment of the invention, the network adapter  100  is being employed in a broadband communications network such as Evolution Data Optimized (EV-DO) and other similar systems. One of ordinary skill in the art can appreciate that the description is for illustrative purposes and not for limitation.  
         [0051]     The network adapter  100  allows a user either via a telephone  205  or a laptop computer  225  or desktop computer  230  via the LAN  220  to transmit wireless data via a broadband cellular network. The digitized voice signal is applied to the wireless network card  125  via the CPU  135 . The wireless network card  125  would be of a type which would allow access to a broadband cellular network. The wireless network card  125  would transmit the voice data in data packets using a code division multiple access (CDMA) scheme, or whatever packet data communications protocol is being used on that broadband network. The voice signal data would be transmitted along a broadband celluar link  265  to the end-user  250 .  
         [0052]      FIG. 3  illustrates a flow diagram of method  300  of the call flow of a user making an outbound telephone call, in accordance with an embodiment of the invention. The method  300  is described with respect to the network adapter  100  shown in  FIG. 1 , but may be applied to other systems.  
         [0053]     In step  305 , the SLIC  140  detects an off-hook condition and notifies the CPU  135 . In step  310 , the DSP (not shown) in the CPU  135  awaits the receipt of the first dual-tone multi-frequency (DTMF) digit from the handset. In step  315 , if the CPU  135  determines from the first digit that the call is to be placed over the relay  160 , then the CPU  135  instructs the DAA  145  to go off-hook, as shown in step  320 .  
         [0054]     In step  325 , the DSP software in the CPU  135  handles the DTMF digits differently depending on whether the call is a VoIP or PSTN call. The routing number path is changed based on whether the call is a VoIP or PSTN call.  
         [0055]     In step  330 , the method  300  determines if the call should be routed to the PSTN. In step  335 , if the DSP software determines the call to be a VoIP call, then the digits are obtained in a loop or stored into the flash memory buffer  110 . In step  340 , if the DSP software determines the call to be a PSTN call, then the digits are obtained in a loop and transferred to the DAA  145  and then transferred to the central office of the local telephone company (not shown).  
         [0056]     In step  345 , the next DTMF digit is received and the method receives the DTMF digits until the last digit has been received in step  350 , which is determined either by a timeout value exceeded while awaiting the digit or by the user pressing the pound key. In step  355 , the method  300  determines whether the last digit has been routed to the PSTN. In the case of a PSTN call, the DAA  145  processes the real time conversion of the analog and digital signal and the call is considered up. In the case of a VoIP voice call, the CPU  135  generates and receives the appropriate messages via WAN  155  based on whatever protocol is used to place the VoIP call. Based on which status message is generated by the far-end analog telephone adapter or VoIP phone (not shown), the CPU  135  produce the appropriate tones to emulate a ringing tone, a busy tone, network congestion tone, etc.  
         [0057]      FIG. 4  illustrates a flow diagram of method  400  of the end of a VoIP call, in accordance with an embodiment of the invention. The method  400  is described with respect to the network adapter  100  shown in  FIG. 1 , but may be applied to other systems.  
         [0058]     In step  405 , the CPU  135  is waiting to detect that the SLIC  140  has detected a hang-up (on-hook) status from the handset or a termination message from the far-end. If as in step  410 , the CPU  135  receives a hang-up acknowledgement from the SLIC  140 , then it sends a termination message to the far-end and waits for the far-end to acknowledge it. In step  415 , once the far-end acknowledges the termination, the call is considered ended and the voice session ends.  
         [0059]     If as in step  420 , a hang-up signal is not detected from the far-end handset, the CPU  135  checks whether a termination has been received from the far-end. In step  425 , if the CPU received a hang-up signal from the called party, then the CPU  135  waits to detect a notification from SLIC  140  that the far-end handset has gone off-hook. Upon notification of the hang-up signal from the SLIC  140 , the call is considered over and the voice session ends.  
         [0060]     In step  430 , after waiting a predetermined amount of time for the hang-up signal, the DSP in the CPU  135  will generate a re-order tone and transmit the tone to the SLIC  140 . The re-order tone is to notify the user that the call has been terminated by the far-end and he needs to hang up the handset. In step  435 , the CPU is waiting to detect a notification signal from SLIC  140  that the far-end handset has gone off-hook. In step  440 , once the CPU  135  gets notification that the user went off-hook, the CPU  135  stops the re-order tone and the call is considered over and the voice session ends.  
         [0061]      FIG. 5  illustrates a flow diagram of method  500  of the call flow of the beginnning of a VoIP call, in accordance with an embodiment of the invention. The method  500  is described with respect to the network adapter  100  shown in  FIG. 1 , but may be applied to other systems.  
         [0062]     In step  510 , the CPU  135  receives RING signals from voice services. The analog telephone adapter receives a message via the broadband modem  240  from a far-end user indicating that they wanted to initiate a call. In step  515 , the CPU  135  instructs the DSP to generate ring tone to the SLIC  140  which generates ring current to be sent to the handset (not shown). In step  520 , the SLIC  140  waits for the handset to go off-hook. In step  525 , once the handset is determined to be off-hook, the CPU  135  sends a notification message to the far-end. In step  530 , the CPU awaits the acknowledgement from voice services on the far-end. Upon receiving the acknowledgement, the internet voice session begins and both parties can begin to stream voice.  
         [0063]      FIG. 6  illustrates a flow diagram of method  600  of the call flow of a call initated by the PSTN, in accordance with an embodiment of the invention. The method  600  is described with respect to the network adapter  100  shown in  FIG. 1 , but may be applied to other systems.  
         [0064]     In step  605 , the network adapter  100  via the DAA  145  receives a message via the broadband modem  240  indicating that someone desires to initiate a call. In step  610 , the CPU  135  instructs the DSP to generate a ring tone to the SLIC  140  which causes ring current to be sent to the handset. In step  615 , the CPU  135  waits for the handset to go off-hook. Once the handset goes off-hook the CPU sends a notification message to the far-end and both parties can begin to stream voice and the PSTN voice session begins.  
         [0065]     In another embodiment of the invention, the network adapter  100  is used to make an emergency call. In prior art systems, there were numerous difficulties in making a 911 call or other emergency call using VoIP technology. For example, the VoIP service did not connect to the 911 service. Moreover, emergency calls made with VoIP service would not include caller-id information indicating the location of the caller, an often important piece of information in an emergency situation. In order to overcome the above stated difficulties, the network adapter can be configured to transfer an emergency call to the PSTN server in order to circumvent the problems associated with using the VoIP server.  
         [0066]      FIG. 7  illustrates a flow diagram of method  700  of the call flow of an emergency call, in accordance with an embodiment of the invention. The method  700  is described with respect to the network adapter  100  shown in  FIG. 1 , but may be applied to other systems.  
         [0067]     In step  705 , the SLIC  140  detects an off-hook condition and notifies the CPU  135 . The DSP (not shown) embedded in the CPU  135  awaits the receipt of the first DTMF digit from the handset. In step  710 , the CPU  135  determines that the call is to be an emergency call. This is determined by the user inputting known DTMF digits according to emergency services, such as 911 call, 311 call and other services known to one of ordinary skill in the art.  
         [0068]     In step  715 , the CPU  135  routes the call to a cellular chip  130  which transmits the call to a receiver via a celluar network  210 . The cellular network chip  130  (or cellular network circuit) acts to modulate the voice signal in a manner which allows it to be transmitted over a cellular network. It will be apparent to one of ordinary skill in the art that there are numerous ways to implement a cellular network, such as GSM, CDMA, UMTS and the embodiment provided is not meant to limit the scope of the invention.  
         [0069]     In step  720 , the cellular network transmits the emergency call to the appropriate public safety answering point (PSAP) in a way known to one of ordinary skill in the art. Once the call has been connected to the PSAP, the emergency call begins over the PSTN and cellular network.  
         [0070]     In further embodiments of the invention, emergency call re-routing functionality may be placed in other components of a telephone system. For example, a cellular interface and re-routing functionality could be implemented within a telephone handset, within a specialized adaptor coupled to a handset or within a conventional personal computer coupled in some manner to a handset.  
         [0071]      FIG. 8  may be used to explain several of these embodiments. That figure depicts a communications network  800 , including a phone  805 , USB adapter  810 , computer  815  and packet-switched network  820 , such as the Internet. In this particular depiction, phone  805  is coupled to computer  815  via a USB adaptor  810 , but that specific interface is included only by way of example and is not necessary or important to the invention. For example, phone  805  may itself be a USB phone and therefore capable of connecting directly to computer  815  via a USB interface, making an intervening adaptor unnecessary. Other communication protocols may also be used in addition to or instead of USB.  
         [0072]     In the system of  FIG. 8 , typical calls using phone  805  would be routed through adaptor  810  and computer  815  to packet-switched network  820  using VoIP technology. Since emergency calls over such a system present problems, as described above, the present invention provides for the inclusion of emergency call re-routing functionality over a cellular interface, or over some other interface designated for emergency situations. Specifically, either phone  805 , adaptor  810  or computer  815  may include a cellular (or emergency) interface, such as a cellular chip or PCMCIA card, and re-routing intelligence, such as specialized application software. The re-routing intelligence is capable of detecting that an emergency call is being made, by detecting that “911” has been dialed for example, and re-routing the call over the cellular interface to a cellular network.  
         [0073]     Note that both the cellular interface and the re-routing intelligence may be included in phone  805 , in adaptor  810  or in computer  815 . Also note, however, that the re-routing intelligence need not be located in the same physical device as the cellular interface, but rather may re-route an emergency call by signaling a separate component that actually includes the cellular interface. For example, in one embodiment, the phone  805  is an ordinary phone, while the adaptor  810  includes the cellular interface and computer  815  includes the re-routing intelligence. In such a system, the re-routing intelligence of computer  815  detects that an emergency call has been made and signals to adaptor  810  to route the call over its cellular interface. (The adaptor, of course, must be provided with the capability to detect and respond to such signaling and also to re-route calls over the cellular interface. Such capability, however, is well within the skill of those of ordinary skill in the art, and will therefore not be further described herein.) Similarly, in yet another embodiment, the cellular interface is disposed within phone  805  while the re-routing intelligence is disposed within computer  815 . In this embodiment, a similar detection and signaling process occurs between the computer and the phone, as will be apparent to those of ordinary skill in the art. Note also that in such an embodiment a separate adaptor component is unnecessary. Indeed, in those embodiments where the re-routing intelligence and emergency interface are disposed within computer  815 , neither phone  805  nor adaptor  810  would be necessary, particularly where computer  815  includes all the usual functionality of a normal handset as would be understood by those of ordinary skill in the art.  
         [0074]     Referring now to  FIG. 9 , which depicts a flow diagram of a re-routed emergency call in accordance with one aspect of the invention, once a user makes a call, the re-routing intelligence determines if the call is an emergency call at step  905 . If not, the call is routed in the normal fashion. As shown in step  910 , if the call is determined to be an emergency call, it is re-routed to the emergency interface, which in this example is a cellular interface. As noted above, that cellular interface may be disposed in any of various system components and the re-routing may entail certain signaling between components. As shown in step  915 , once the call has been re-routed, the call is transmitted over the cellular interface to a cellular network, which in turn transmits the call and special service information, including caller location information, to a PSAP, in a conventional manner, as shown in step  920 .  
         [0075]      FIG. 10  shows a computer system  1000  including a device  1010  for use with a computer  1100 . The device  1010  includes control logic  1020 , such as a controller, a dedicated processor and/or a CPU, that receives a first signal  1030 , such as an analog or digital signal. The analog signal may be a dual-tone multi-frequency based signal. If the control logic  1020  receives an analog signal, it may have some associated analog to digital converter to convert the analog signal  1035  to a digital signal for processing. Thus, if the first signal  1030  is a digital signal, it may have been converted from an analog signal via the use of an analog to digital converter  1040 , which could be included in the device  1010 . Also, the reference to a signal herein may include a signal incorporating multiple signals.  
         [0076]     The control logic  1020  evaluates the first signal  1030  to determine whether the first signal  1030  corresponds to an emergency call, which may be an emergency “911” call. The control logic  1020  outputs a second signal  1050  if it is determined that the first signal corresponds to an emergency call. The second signal  1050  may be identical to the first signal  1030  or merely derived from the first signal  1030 .  
         [0077]     The device  1010  may also include a first transceiver  1060  that receives the second signal  1050  from the control logic  1020  and transmits a radio signal  1065  to establish a two-way communication channel corresponding to the emergency call upon receipt of the second signal  1050 . The two-way communication channel may include a commercial mobile radio service (“CMRS”).  
         [0078]     In accordance with another embodiment of the invention, the control logic  1020  may also determine if the first signal  1030  corresponds to an outbound call other than an emergency call, and if so, provide the first signal  1030  to the computer  1100  if it is determined that the first signal  1030  corresponds to an outbound call other than an emergency call. The computer  1100  then facilitates the transfer of a third signal  1110 , which is a digital signal, corresponding to the outbound call via one or more data networks  1120 . The outbound call may be implemented as a VoIP call. The third signal  1110  may include at least one packet of data (not shown) and an address (not shown) corresponding to a remote device  1150  that is to receive the packet of data.  
         [0079]     The device  1010  may include a connector  1070  that couples the device to the computer  1100 . The connector  1070  may be a USB connector or an Ethernet or other connector. The device may also be wirelessly coupled to a computer via, for example, a second transceiver  1080 .  
         [0080]     The control logic  1020  and/or the first transceiver  1060  may be implemented on an application specific integrated chip (not shown), which will greatly facilitate its use in a miniature device. The control logic  1020  and/or first transceiver  1060  may be implemented on a card (e.g., a PCMCIA card) (not shown) to be inserted within a slot of the computer  1100 . Alternatively, the control logic  1020  and/or first transceiver  1060  may be built into the computer  1100 , obviating the need for a separate device  1010  or simplifying the device  1010  by having only the control logic  1020  or first transceiver  1060  located therein. In a streamlined implementation of a preferred embodiment, the device  1020  and/or computer  1100  may be implemented without a subscriber identity module or a connector for a subscriber identity module.  
         [0081]     The computer  1100  includes one or more processors  1160  (e.g., CPU), controllers (not shown) and/or control logic (not shown) coupled to memory  1170 , such as a RAM, a ROM, an SDRAM, an EEPROM, a flash memory, a hard drive, an optical drive and/or a floppy drive. The control logic  1020  of the device  1010  may also have such memory associated with it to store software and/or data used by the software to implement the present invention.  
         [0082]     The computer  1100  may be accessible to a user directly or indirectly via one or more data networks  1120 , such as a local area network, wide area network, wireless network, or the Internet. If the computer  1100  is directly accessible, the user may interact with the computer  1100  via input output devices (not shown), such as a keyboard, mouse or trackball. In addition, the computer  1100  may have a display  1190 , such as a monitor, LCD display or plasma display, which displays information to the user. The computer  1100  may also be coupled to a printer (not shown) for printing information.  
         [0083]     The computer  1100  stores in the memory  1170  the software (and corresponding data) that is used to implement an embodiment of the present invention. Also stored in the memory  1170  of the computer  1100  are the data relied upon by the software application code of the present invention. The software application code may also be implemented in hardware via a dedicated device incorporating control logic or a controller, for example. The software application code includes software instructions to be executed by the processor  1160  or some other processor which is separate from the CPU of the computer  1100 . Alternatively, the software may be executed by a processor, a controller, or control logic on the device  1010 .  
         [0084]     In execution, the software application code causes the processor  1160  to receive a first signal (e.g., the first signal  1030 ) and evaluate the first signal to determine whether the first signal corresponds to an emergency call. The software application code may do so by, for example, evaluating a signal representing the frequencies of one or more signals corresponding to key presses in a DTMF implementation. Accordingly, if key presses corresponding to “9”, “1”, “1” are associated with an emergency call, then it shall be determined whether a signal includes an indicia of frequencies corresponding to those key presses to identify an emegerncy call. The software application code also causes the processor  1160  to output a second signal (e.g., the second signal  1050 ) to a first transceiver (e.g., the first transceiver  1030 ) if it is determined that the first signal corresponds to an emergency call. The first transceiver is capable of receiving the second signal from the processor and transmitting a radio signal (e.g., the radio signal  1065 ) to establish a two-way communication channel corresponding to the emergency call upon receipt of the second signal. The two-way communication channel may include a commercial mobile radio service (“CMRS”). The emergency call may be made to, for example, an emergency operator.  
         [0085]     In execution, the software application code may also cause the processor  1160  to determine if the first signal corresponds to an outbound call other than the emergency call, the processor  1160  facilitating the transfer of a third signal (e.g. the third signal  1110 , which may be a digital signal) corresponding to the outbound call via one or more data networks  1120  if it is determined that the first signal corresponds to an outbound call other than the emergency call. This may be accomplished in a manner similar to that described above in connection with the detection of an emergency call in a DTMF based implementation, except that a signal is evaluated to determine that it does not contain an indicia of frequencies corresponding to those key presses which are associated with an emergency call. As noted above, the outbound call may be implemented as a VOIP call and the third signal may include at least one packet of data and an address corresponding to a remote device  1150  that is to receive the packet of data.  
         [0086]      FIG. 11  depicts a method for making a telephone call including the step  1200  of evaluating, in a computer or a device (for use with a computer), a first signal (e.g., the first signal  1030 ) to determine whether the first signal corresponds to an emergency call, such as an emergency “911” call. The first signal may be an analog or digital signal. The analog signal may be a dual-tone multi-frequency based signal. If the first signal is a digital signal, it may have been converted from an analog signal via the use of an analog to digital converter (e.g., the analog to digital converter  1040 ). Thereafter, in the step  1210 , a transceiver (e.g., the transceiver  1030 , which may or may not be located in the computer  1100 ) transmits a radio signal to establish a two-way communication channel corresponding to the emergency call if it is determined that the first signal corresponds to an emergency call. The two-way communication channel may include a commercial mobile radio service (“CMRS”).  
         [0087]     The method may also include the step  1220  of evaluating, in the computer or device, the first signal to determine if the first signal corresponds to an outbound call other than the emergency call. Thereafter, in step  1230 , if the first signal is generated outside of a computer, then it is provided to a computer if it is determined that the first signal corresponds to an outbound call other than the emergency call. Thereafter, in step  1240 , a second signal is transferred via a data network (e.g., the data network  1120 ), the second signal (which may be a digital signal) corresponding to the outbound call via a data network. As noted above, the outbound call may be implemented as a VoIP call and the second signal may include at least one packet of data and an address corresponding to a remote device (e.g., the remote device  1150 ) that is to receive the packet of data.  
         [0088]     What has been described and illustrated herein is a preferred embodiment of the invention along with some of its variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the invention, which is intended to be defined by the following claims, in which all terms are meant in their broadest reasonable sense unless otherwise indicated therein.