Abstract:
Systems for dialing an emergency telephone number from a teleworking client according to the invention include apparatus that implement the steps of detecting at a teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing an associated stored number. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection.

Description:
[0001]    This application is related to co-owned co-pending application Ser. No. ______ filed Nov. 8, 2000, entitled “Method and Apparatus for Extending PBX Features via the Public Network”, the complete disclosure of which is hereby incorporated herein by reference.  
         [0002]    This application is further related to co-owned co-pending application Ser. No. ______, filed ______, entitled “Priority Based Methods And Apparatus For Transmitting Accurate Location identification Numbers (LINs) From Behind A Multiline Telephone System (MLTS)”; co-owned co-pending application Ser. No. ______, filed ______, entitled “Methods And Apparatus For Transmitting Accurate Location Identification Numbers (LINs) From Behind A Multiline Telephone System (MLTS) Utilizing Port Equipment Numbers”; co-owned co-pending application Ser. No. ______, filed ______, entitled “Methods And Apparatus For Transmitting Accurate Location Identification Numbers (LINs) From Behind A Multi-Line telephone System (MLTS) After An Emergency Caller Disconnects”; co-owned co-pending application Ser. No. _______, filed ______, entitled “Methods And Apparatus For Transmitting Accurate Location Identification Numbers (LINs) After An Emergency Caller Disconnects”; and co-owned co-pending application Ser. No. ______, filed ______, entitled “Methods And Apparatus For Dialing An Emergency Telephone Number From A Teleworking Client Remotely Coupled To A PBX”, the complete disclosures of which are hereby incorporated by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The invention relates to methods and apparatus for dialing an emergency telephone number from a teleworking client remotely coupled to a PBX. More particularly, the invention relates to methods and apparatus for intercepting dialed digits (e.g., TAPI messages, DTMF tones) dialed by the teleworking client, uncoupling the teleworking client from the PBX, coupling the teleworking client to the PSTN, and transmitting the digits as DTMF tones over the PSTN.  
           [0005]    2. Brief Description of the Prior Art  
           [0006]    People can access a wide variety of services and functions through telecommunications systems. A subscriber can receive, send, and forward voice messages, faxes, e-mail, and data, and can remotely manage many business and personal functions.  
           [0007]    This new technology has important implications for teleworking. In teleworking, a teleworker performs work functions from a remote location. In many cases, a teleworker can perform functions identical to those performed by her colleague in the office. Teleworking can be loosely defined as workers performing work functions remotely through a telecommunications system.  
           [0008]    Teleworking offers workers unprecedented flexibility and convenience for workers. It also provides opportunities for people who have traditionally been excluded from the work force or who have been able to participate on a limited basis only. It can remove geographical barriers, better integrate the disabled into the work force, and provide retraining and rehabilitation programs for the institutionalized.  
           [0009]    Most advanced features are implemented and controlled through a control channel, which requires the user to have a telephone system, typically ISDN, that provides a separate channel for the control signal. Unfortunately, many subscribers do not have ISDN telephones or ISDN lines. ISDN telephones and lines are particularly rare in private homes, locations where teleworking can make the biggest difference. What is needed is a better way to integrate ordinary subscribers into teleworking.  
           [0010]    The above referenced previously incorporated application entiled “Method and Apparatus for Extending PBX Features via the Public Network”, discloses a system and method for allowing clients with a variety of teleworking devices, including digital and/or non-specialized dual-tone multi frequency (DTMF) telephones, to invoke PBX (private branch exchange) features. The user can invoke all or, alternatively, major PBX functions from any location.  
           [0011]    In a preferred embodiment of the application referenced in the previous paragraph, a mobility circuit board system (IGate, SMPLX, WAML) includes a set of ports, called (herein) fictitious ports, that are not dedicated to fixed branch extensions. A fictitious port on a mobility board is assigned to a teleworker. The circuit board is responsible for enabling a teleworker at a remote phone to be treated by the switch as if he were connected to a standard physical port of the switch. When a teleworker logs in, he is assigned a fictitious port, which supports access to PBX functions.  
           [0012]    After logging in, the teleworker can input digits to access PBX features (via feature code) or digits to call an inside or outside party via routing through the PBX. The digits are sent to the teleworking server (TW server, TWS). If a feature code is recognized by the server, the digits are suppressed from reaching the other party, and the teleworking server invokes the requested feature and sends the proper signals to the switch. The system thus provides the teleworker PBX functions at any location. In alternatives, an interactive voice recognition (IVR) system with prompts can be used to signal selection of PBX features.  
           [0013]    Among other features, the system and method also provide for identification and call-back to avoid toll charges; activation and deactivation of call redirection; entering new call redirection destinations; identification of call redirection phone numbers; receiving and making both business and personal calls; activation and deactivation of voicemail and fax mail notifications; locating the teleworker; and dialing into specific numbers that activate and/or deactivate teleworking features without requiring user input and without requiring the call to be answered.  
           [0014]    A method  300  for logging in is illustrated in FIG. 4. At step  302 , the teleworking client calls the system. (In alternatives, the system places a call to the teleworking client.) At step  304 , the teleworking client logs in, including an optional sub-step  306 , at which the calling line is identified, and an optional sub-step  308 , at which the teleworking client enters a PIN. Neither step, either step, or both steps can be implemented as part of login. Furthermore, other identifiers such as voice recognition can be added or used as alternatives.  
           [0015]    At step  310 , the teleworking server (TWS) checks the login. If the login is not approved, the method loops back to step  304 . As indicated by optional step  312 , the number of attempts can be regulated by an attempt counter or a timeout timer. If the process times out, the method ends, at a step  314 .  
           [0016]    If the login is approved, the method continues to step  316 , and the IGate assigns a fictitious port to the user. At a step  318 , the TWS assigns the teleworking client&#39;s office extension to the fictitious port. An optional step  320  makes a subset of PBX features available to the fictitious port; alternatively, the full set of features is available. At a step  322 , the PBX features can be accessed at the teleworking client&#39;s remote site, the site from which the original call was placed.  
           [0017]    One unusual problem arises when a teleworking client is coupled to a remote PBX/MLTS (multiline telephone system) and the teleworking client calls an emergency telephone number. In the U.S., the number 911 is designated as an emergency number through which police, fire, and medical emergencies may be reported.  
           [0018]    Normally, when a caller dials 911, the call is directed to a public safety answering point (PSAP) with a Caller ID (i.e., a subscriber line e.g., analog, BRI or Calling Party Number (CPN/ANI) (i.e., PRI or CAMA trunk). When the Caller ID is on a device behind a PBX/MLTS, an emergency location identification number (ELIN as defined by the National Emergency Number Association), in addition to the caller ID, is currently required by some legislative bodies to be transmitted from the caller&#39;s PBX/MLTS to the central office and the PSAP. The ELIN represents (i.e., indicates a 10-digit NANP number) the location of the caller, e.g. street address.  
           [0019]    When a teleworking client calls 911, the call is handled by the PBX/MLTS as if the caller were located at the same location as the PBX/MLTS. Thus, incorrect ELIN and caller ID information are transmitted to the PSAP. Moreover, the call may not even be directed to the correct PSAP as the teleworking client and the PBX/MLTS may be located in different PSAP jurisdictions e.g., cities or even different states.  
         SUMMARY OF THE INVENTION  
         [0020]    It is therefore an object of the invention to provide methods and apparatus for dialing an emergency telephone number from a teleworking client.  
           [0021]    It is also an object of the invention to provide methods and apparatus for intercepting “emergency” digits dialed by the teleworking client, uncoupling the teleworking client from the PBX/MLTS, coupling the teleworking client to the PSTN, and transmitting the emergency digits over the PSTN.  
           [0022]    It is another object of the invention to provide methods and apparatus for maintaining a database of emergency numbers to be intercepted.  
           [0023]    In accord with these objects which will be discussed in detail below, the methods according to the invention include detecting at the teleworking client when an emergency number is dialed, disconnecting the teleworking client from the PBX/MLTS, connecting the teleworking client to the PSTN, and dialing a stored number associated with that number which was dialed. The apparatus of the invention resides in software that is installed in off the shelf hardware. Though the invention is described with reference to a teleworking client, it may also be applied to any other dialup network connection. The emergency digits (dialed and subsequently signalled to the PSTN) are not limited to emergency numbers, but are determined by the TW client via administration. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    [0024]FIG. 1 is a high level schematic diagram of a system according to the invention;  
         [0025]    [0025]FIG. 2 is a high level block diagram of teleworking client software according to the invention;  
         [0026]    [0026]FIG. 3 is a simplified flow chart illustrating the methods of the invention; and  
         [0027]    [0027]FIG. 4 is a simplified flow chart illustrating co-owned related technology.  
     
    
     DETAILED DESCRIPTION  
       [0028]    Turning now to FIG. 1, a system according to the invention includes a PBX/MLTS  10  coupled to local phone sets  12  and a local area network (LAN)  14  servicing multimedia PCs  16 , a teleworking server  18 , a data server  20 , and a security server  22 . The PBX/MLTS  10  is coupled to the PSTN (public switched telephone network)  28  via a gateway  24  and an access server  26 .  
         [0029]    According to the system of the invention, remote teleworking clients  30 ,  34  access the PBX/MLTS  10  and the LAN  14  via the PSTN  28 . Teleworking clients may include separate telephones  30  and PCs (hybrid clients) or may include a multimedia IP client  34 . According to the invention specialized software, described below with reference to FIGS. 2 and 3, supports the teleworking client.  
         [0030]    According to the invention, a hybrid client  30 ,  32  uses two links to the PBX/MLTS  10 : one for voice information and one for multiplexed data and signaling information. The two links could be provided by an ISDN basic rate interface (BRI) or two analog dialup connections or any means of data connectivity (e.g., T3, T1, DSL, cable modem). Depending on the different link types the following clients can be differentiated.  
         [0031]    A teleworking IP client  34  according to the invention preferably includes a standard off the shelf PC so long as it is able to support IP based protocols (e.g., H.323, SIP, etc.) for voice and Multi Media data and signaling information data streams via an appropriate network interface (excluding IP only phone Client).  
         [0032]    Turning now to FIG. 2, an example of teleworking client software  40  according to the invention includes a user interface  42  through which a user gains access to applications  44 . The applications  44  communicate with a session manager  52  via a plurality of application programming interfaces (APIs)  46 ,  48 ,  50 . The session manager  52  communicates with the PSTN via the call service manager  54  and with the teleworking A/V hardware via the media service manager  56  (both shown included, along with emergency caller module  58 , as part of client software  53  depicted in FIG. 3).  
         [0033]    More particularly, the call service manager  54  communicates with the network via a call control module  60  through a LAN connection  66 . According to the invention, an emergency caller module  58 , described in more detail below with reference to FIG. 3, monitors network traffic for a defined sequence of dialed digits. The media service manager  56  communicates with various terminal adapters  68 ,  70  via service providers  62 ,  64 .  
         [0034]    According to the presently preferred embodiment, the emergency caller module  58  is associated with a database  72  of emergency numbers. The database  72  is provided with an administration interface  74  through which the teleworking user may enter/edit numbers that will be intercepted by the emergency caller module  58 . According to an optional feature of the invention, the database and administration may be configured such that an intercepted number is associated with another number that will be dialed via the PSTN.  
         [0035]    For example, if a teleworking user is connected to the PBX/MLTS via another PBX, e.g. in a hotel that provides a separate data connection, which requires that the user dial a digit, e.g.  9 , to be connected to an outside line, the software can be programmed to insert the extra digit before dialing the emergency number. According to a further preferred embodiment, the emergency caller module  58  monitors dialed digits when a teleworking session is active and a new call has been placed.  
         [0036]    [0036]FIG. 3 depicts the high-level processing of the invention that begins when the teleworking client has logged on and has an active session as illustrated at  100 . Monitoring for digits dialed by the teleworking client user begins at  102 . When a dialed digit is detected, a digit pattern matching function is performed at  104 . If it is determined at  106 , that the digits do not match a number in the database of emergency numbers, the software returns at  108  to monitor digits for the next call.  
         [0037]    According to the presently preferred embodiment, the first digit is compared to the first digit of the associated pre-defined database of emergency numbers. If no match is found, the search is ended with no match. If a match is found, the second digit is collected and compared to the second digit of the associated pre-defined table of emergency numbers for those numbers which matched on the first digit. If no match is found, the search is ended with no match. If a match was found, the third digit is collected and compared to the third digit of the associated pre-defined table of emergency numbers for those numbers which matched on the first and second digit.  
         [0038]    This process continues until either no match is determined or the digit string match is found at  106 . Though not shown in FIG. 3, when a match is found, the database entry corresponding to the dialed emergency number is remembered for use in dialing over the PSTN.  
         [0039]    If a match is found, the teleworking session is immediately disconnected at  110  (i.e., logged off, link dropped). An on-hook event is sent to the public network followed by an off-hook event at  112 . When dial tone is received (i.e., from public network) at  114 , the indicated number in the database (plus any programmed prefix) is automatically “outpulsed” on behalf of the teleworking user at  116 . The emergency call monitoring is then stopped at  118 . A normal public network call is in progress (i.e., no teleworking session). It is routed correctly to the proper PSAP with the correct call information (i.e., calling directory number).  
         [0040]    There have been described and illustrated herein methods and apparatus for dialing an emergency number from a client coupled to a remote network via the PSTN. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.