Patent Abstract:
Surveillance of IP telephony may be performed through the use of conventional telephone equipment, according to principles of the invention while preventing giving indication to the monitored phone by alerting the user of the monitoring phone to such surveillance use prior to pick up by an agent for engagement of the monitoring phone in response to the alert. Such alerts may assume many forms such as ringing, visual indicators, data readouts, activating ancillary equipment, various flags, etc. This alert prior to surveillance is distinct from alerts used for normal non-surveillance calls, which the monitoring phone is capable of receiving.

Full Description:
This application is a continuation of and claims priority to U.S. application Ser. No. 10/298,844, filed Nov. 19, 2002, now U.S. Pat. No. 7,428,233, issued Sep. 23, 2008, which is a continuation of and claims priority to U.S. Pat. No. 6,563,797, filed Aug. 18, 1999, and issued May 13, 2003, the contents of both of which are incorporated herein by reference in their entirety. 
    
    
     FIELD OF TECHNOLOGY 
     The present disclosure relates to surveillance of telephone calls over a public communications link and is particularly concerned with providing assistance for such surveillance to law enforcement agencies. It particularly concerns surveillance of voice over IP (i.e., cable) networks. 
     BACKGROUND 
     Requirements for enabling surveillance of electronic communications have been enacted into public law (e.g., Public Law 103-414 enacted Oct. 25, 1994; CALEA Communications Assistance for Law Enforcement Act) reciting requirements for assuring law enforcement access to electronic communications. Such access is required to be in real time, have full time monitoring capabilities, simultaneous intercepts, and feature service descriptions. The requirements specifically include capacity requirements and function capability. It is incumbent upon communication carriers to provide such capability and capacity. 
     While initially limited in scope, at present, to certain communications technology it is almost assured that it will be extended to new forms of communication. New technologies require extension of CALEA to the new phone system technologies. With the advent of IP telephony it is desirable to provide surveillance capabilities for application to IP telephony. 
     One of the impediments to surveillance is the necessity of having dedicated equipment to perform the monitoring function. It would be useful to perform such surveillance of a targeted phone with non-dedicated telephone equipment. With use of such non-dedicated equipment it is desirable to distinguish normal calls from surveillance calls. 
     BRIEF SUMMARY 
     Surveillance of IP telephony may be performed through the use of conventional telephone equipment, according to principles of the invention while preventing giving indication to the monitored phone of the monitoring activity. The user of the monitoring phone is alerted to such surveillance use prior to pick up, by an agent for engagement of the monitoring phone, in response to the alert. Such alerts may assume many forms such as ringing, visual indicators, data readouts, activating ancillary equipment, various flags, etc. This alert prior to surveillance is distinct from alerts used for normal non-surveillance calls, which the monitoring phone is capable of receiving. 
     In an IP telephone environment, a cable modem bank (CMB) or an IP Phone intercept List (IP-PIL) lists the IP phones to be monitored and responds when one of those listed phones to be monitored becomes active. In response to notification by an IP Address Mapping Check Point with the IP-PIL, a distinctive alert is delivered to the monitoring phone, which indicates the call&#39;s existence and the monitoring purpose to be performed. The IP Address Mapping Check Point and associated WatchDog program alerts the monitoring phone when the monitored phone is in the process of receiving a call. In both instances the monitoring phone is controlled not to be active until both parties of the monitored call are connected and active. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present disclosure and the advantages thereof may be acquired by referring to the following description in consideration of the accompanying drawings, in which like reference numbers indicate like features and wherein: 
         FIG. 1  is a block schematic of a surveillance system incorporating the principles of the invention; and 
         FIG. 2  is a flow chart of the process by which the invention is performed in the system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of the various embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration various embodiments in which aspects of the disclosure may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present disclosure. 
     A monitoring station/location  101  is shown, in the  FIG. 1 , as connected, via a broadband gateway  121 , to a backbone Internet Protocol (IP) network  103  via the connection provided by an Hybrid Fiber Coax (HFC) distribution plant  105 . HFC distribution plant  105  is a distribution cabling arrangement employing both optical fiber and coaxial cable. Optical fiber is connected to the backbone and coaxial cable is connected to the terminating devices. The optical fiber and coaxial cable are joined by an electro-optical connection. The objective is to provide higher bandwidth to the terminating devices at a lower cost then by using optical fiber alone. 
     The target telephone/DN  111  to be monitored is also connected, via a broadband gateway  131 , to the backbone IP network  103  via the same HFC distribution plant  105 . Included with the backbone IP network is an IP address mapping Check Point (IP-AMCP)  125 , which provides numbers for various devices, connected to the backbone network  103 . The IP-AMCP  125  may be embodied in a server within or connected to the network. It has the capability, through programming, of examining packet contents and authenticating users of the network. With specific WatchDog software  127  the IP-AMCP identifies specific activity from certain designated telephone stations  112  and/or  113  at a specified DN or IP address and can replicate/duplicate the packets of that phone and the IP target telephone  111  which replicated/duplicated packets are forwarded to the monitoring station  101 . 
     The designated telephone stations  112  and  113  may be connected to the IP network  103  or to the Public Switched Telephone Network (PSTN)  115 , as shown, and be connected to the target DN  111 . The monitoring station  101  may not be dedicated to the surveillance function and hence some indication of its use is provided. The IP-AMCP  125  through its WatchDog  127  determines when an incoming call to the monitoring station is a surveillance call of the target DN  111 . It uses this determination to provide an alerting signal to the monitoring station  101  so that the answerer is knowledgeable that the incoming call is a monitoring of a target IP telephone. In one aspect the gateway coupling the monitoring IP telephone to the IP network is a source of distinctive ringing signals or in the alternative provides an audio announcement. 
     The procedure in providing such an indicating alert is shown in the flow chart of  FIG. 2 . It starts, as indicted in block  203 , with the initiation of a call to an IP telephone having a known DN. A WatchDog program associated with the IP-AMCP notes that the call is being initiated as per block  205 . In decision block  207  an inquiry asks if the called DN is one of a list of IP telephone under surveillance. If it is not the flow proceeds per the instructions of block  209  to handle the call as a non-monitored call and the process ends at terminal  219 . 
     If the DN called is on the surveillance list the process as per block  211  locates the addresses of the calling and called DNs in the IP-AMCP. According to the instructions of block  213  the IP-AMCP sends a distinctive alert message to a gateway terminal connecting the target IP telephone to the IP network and also to the gateway serving the monitoring IP telephone. In the instance of the gateway of the monitoring IP telephone the gateway in one embodiment rings the monitoring IP telephone with a distinctive ring, as per block  215 , to indicate to the party answering the phone that this is a call connection for the purpose of eavesdropping in on the target IP telephone. In an alternative arrangement the gateway may have a facility to provide this information by means of an audio output. The monitoring process then proceeds, as per block  217 , until termination of the call where upon the process ends at terminal  219 . 
     The following applications are being filed concurrently with the present application and are incorporated herein by reference. All applications have the same inventors (e.g., Kung, Russell, Sankalia and Wang):
         U.S. Pat. No. 6,381,220, entitled, Monitoring Selected IP Voice Calls Through Activity of a WatchDog Program at an IP-Addressing Mapping Checking Point, filed Aug. 18, 1999, and issued Apr. 30, 2002;   U.S. patent application Ser. No. 09/375,750, entitled, Monitoring IP Voice Calls Under Command of a PSTN Phone, filed Aug. 18, 1999;   U.S. Pat. No. 6,501,752, entitled, Flexible Packet Technique for Monitoring Calls Spanning Different Backbone Networks, filed Aug. 18, 1999, and issued Dec. 31, 2002;   U.S. Pat. No. 6,553,025, entitled, Multiple Routing and Automatic Network Detection of a Monitored Call from an Intercepted Targeted IP Phone to Multiple Monitoring Locations, filed Aug. 18, 1999, and issued Aug. 22, 2003;   U.S. Pat. No. 6,496,483, entitled, Secure Detection of an Intercepted Targeted IP Phone from Multiple Monitoring Locations, filed Aug. 18, 1999, and issued Dec. 17, 2002; and   U.S. Pat. No. 6,560,224, entitled, Automatic IP Directory Number Masking and Dynamic Packet Routing for IP Phone Surveillance, filed Aug. 18, 1999, and issued May 6, 2003.       

     While exemplary systems and methods embodying the present inventions are shown by way of example, it will be understood, of course, that the invention is not limited to these embodiments. Modifications may be made by those skilled in the art which differ from the specific details disclosed here, but which are still within the scope of the invention. Further elements of one invention may be readily included as elements of one of the other inventions. Those skilled in the art may combine or distribute the elements in many different ways without departing from the spirit and scope of the invention. 
     As can be appreciated by one skilled in the art, a computer system with an associated computer-readable medium containing instructions for controlling the computer system can be utilized to implement the exemplary embodiments that are disclosed herein. The computer system may include at least one computer such as a microprocessor, digital signal processor, and associated peripheral electronic circuitry. 
     While the disclosure has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims.

Technology Classification (CPC): 7