Abstract:
A method and apparatus are disclosed that enable a data-processing system, such as a server, to determine whether or not to grant a telecommunications terminal one or more privileges, without some of the disadvantages of the prior art. Specifically, in accordance with the illustrative embodiments of the present invention, a call-processing server transmits, to a first terminal, a first signal for verifying a second terminal, such as one that has been designated by a user. The user is then required to transmit a second signal to the call-processing server via the second terminal. The call-processing server then examines the received second signal with respect to the first signal and determines whether or not to grant the second terminal a privilege (e.g., handling calls on behalf of the user, etc.), based on the relationship between the first and second signals.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to telecommunications in general, and, more particularly, to determining whether or not to grant a privilege to a telecommunications terminal.  
       BACKGROUND OF THE INVENTION  
       [0002]      FIG. 1  depicts a block diagram of telecommunications system  100  in the prior art. Telecommunications system  100  comprises: designating telecommunications terminal  101 , designated telecommunications terminal  102 , call-processing server  103 , telecommunications network  104 , and telecommunications terminal  105 , interconnected as shown.  
         [0003]     Designating telecommunications terminal  101  is a personal computer (e.g., a laptop, etc.) that runs software that enables the terminal to provide telecommunications services to its user by transmitting and receiving packets of information. In this capacity, terminal  101  can be referred to as a softphone. Some of the telecommunications services that terminal  101  provides include placing and receiving calls, emailing, instant messaging, and so forth. Terminal  101  interacts with call-processing server  103  via a signaling channel to initiate a session to provide a telecommunications service. Terminal  101  uses the Session Initiation Protocol (or “SIP”) set of rules to initiate a session. Once a session has been initiated, terminal  101  transmits via telecommunications network  104  session-related traffic, such as voice or data, in packet format to one or more destinations, and also receives, via network  104 , session-related traffic from one or more sources. Terminal  101  transmits and receives traffic by using the Internet Protocol set of rules and, as such, is an Internet Protocol-based terminal that is capable of providing Voice over Internet Protocol (or “VoIP”) to its user, among other services.  
         [0004]     Designated telecommunications terminal  102  is a telecommunications terminal that is capable of exchanging information with call-processing server  103  for the purposes of transmitting or receiving voice or data traffic. Terminal  102  might be a packet-based terminal, similar to terminal  101 , or it might be a circuit-based terminal based on older technology, such as a Plain Old Telephone Service (or “POTS”) wireline telephone. As part of a call or session, terminal  102  transmits and receives voice and data traffic via what is sometimes referred to as a media channel.  
         [0005]     Call-processing server  103  is a data-processing system (e.g., at an office building, at a central office switching center, etc.) that is capable of exchanging signaling information and traffic with terminals  101  and  102 . Call-processing server  103 &#39;s interaction with terminals  101  and  102  is supported by telecommunications network  104 .  
         [0006]     Telecommunications network  104  enables the transport of signaling information, as well as voice and data traffic, between the endpoints (e.g., terminal  101 , call-processing server  103 , etc.) in telecommunications system  100 . Telecommunications network  104  might comprise one or more of the Public Switched Telephone Network, the Internet, one or more dedicated packet-based networks, and so forth.  
         [0007]     The softphone functionality of designating telecommunications terminal  101  enables its user to designate an endpoint in telecommunications system  100 , such as designated telecommunications terminal  102 , as having one or more privileges. One example of a privilege is handling all calls made to the user. A softphone user might want to designate another terminal to handle calls because the other terminal, for example, (i) offers better quality, (ii) is more capable, or (iii) has greater reliability than the user&#39;s laptop. To designate terminal  102  to be the recipient of calls, the user enters the address of terminal  102  (e.g., a telephone number, an Internet Protocol address, etc.) on his laptop (i.e., terminal  101 ), and the softphone application transmits the user request to call-processing server  103 .  
         [0008]     The problem with a softphone having the capability to designate another terminal is that malicious software, or “malware,” also can designate another terminal (e.g., telecommunications terminal  105 , etc.) without the user&#39;s knowledge. The malware (e.g., a computer virus, etc.) introduced by an adversary could use the softphone for toll fraud in a manner described here. The malware could access and activate terminal  101 , and designate the adversary&#39;s current terminal (i.e., terminal  105 ) to place and receive calls. The softphone could then be instructed to call the telephone number of the adversary&#39;s choice. The malware could be controlled via instructions from an external server to which the malware connects.  
         [0009]     Some security techniques in the prior art offer some protection against malware. For example, the user could be required to provide a user name and password to the call-processing server in order to designate another terminal. Password-based techniques are fallible, however, in that either (i) the user might have already successfully gained access before the malware activates the softphone or (ii) the softphone might store the user name and password information as a convenience to the user, only to have the malware steal the information.  
         [0010]     What is needed is a technique for determining whether or not to grant a telecommunications terminal one or more privileges, without some of the disadvantages of the prior art.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention enables a data-processing system, such as a server, to determine whether or not to grant a telecommunications terminal one or more privileges, without some of the disadvantages of the prior art. Specifically, in accordance with the illustrative embodiments of the present invention, a call-processing server transmits, to a first terminal, a first signal for verifying a second terminal, such as one that has been designated by a user. The user is then required to transmit a second signal to the call-processing server via the second terminal. The call-processing server then examines the received second signal with respect to the first signal and determines whether or not to grant the second terminal a privilege (e.g., handling calls on behalf of the user, etc.), based on the relationship between the first and second signals.  
         [0012]     Two illustrative embodiments of the present invention are disclosed. The first illustrative embodiment is applicable to a server determining, in general, whether or not to grant privileges to a terminal. The second illustrative embodiment is applicable to a server, along with an interactive voice response (IVR) system, determining whether or not to grant privileges to a designated terminal (e.g., a hotel room telephone, etc.), where the access to the terminal is controlled by a private branch exchange (e.g., a hotel switchboard staffed by an operator, etc.).  
         [0013]     In accordance with the first illustrative embodiment of the present invention, the user of a first terminal (e.g., a softphone implemented on a laptop that runs Session Initiation Protocol, etc.) registers with a call-processing server and designates a second terminal (e.g., a home telephone, etc.) to receive traffic (e.g., voice traffic, data traffic, text messages, etc.) that is intended for the user. The server provides a first signal to the first terminal via the signaling channel, wherein the first signal represents information that requires an action by the user (e.g., providing a response, etc.). The server also calls the second terminal. The user answers the incoming call to the second terminal. Using the second terminal, the user provides back to the server (e.g., via entering selections on a keypad, etc.) a second signal that has some relationship to the first signal. For example, the first signal can be a distorted image of a word that is readable by the user, but not as easily readable by a machine (i.e., the first terminal), in which case the user in the second signal verifies the word back to the server using the second terminal. The user&#39;s terminal transmits the second signal to the server via a communications channel (e.g., a media channel, etc.) that is different than the signaling channel. If the second signal compares satisfactorily to the first signal, the server grants the second terminal privileges (e.g., placing calls, receiving calls, accessing a database, etc.).  
         [0014]     In some alternative embodiments, instead of transmitting and receiving the first and second signals via a signaling channel and a media channel, the server transmits and receives the signals via another pair of different communications channels. For example, the two different communications channels can be a signaling channel and a circuit-switched channel, two different radio frequency channels, two different timeslots of information transmitted on the same wire, two transmission channels on different coaxial cables, and so forth.  
         [0015]     In accordance with the second illustrative embodiment of the present invention, the user of a first terminal (e.g., a softphone implemented on a laptop or notebook computer, etc.) registers with a call-processing server and designates a second terminal (e.g., a hotel room telephone, etc.) to receive traffic (e.g., voice traffic, data traffic, text messages, etc.) that is intended for the user. The user designates the second terminal by specifying a telephone number (e.g., the main number of a hotel, etc.) and an extension (e.g., the particular hotel room phone, etc.). In response, the server enlists an interactive voice response (IVR) system to call the designated telephone number and to indicate to the answering party (e.g., a hotel operator, etc.) that a caller is attempting to reach the user at the designated extension. The server also provides a first signal to the first terminal via the signaling channel, wherein the first signal represents information that requires an action by the user.  
         [0016]     The answering party puts the IVR system-originated call through to the user. Using the second terminal, the user provides back to the IVR system a second signal that has some relationship to the first signal. If the second signal compares satisfactorily to the first signal, the IVR system notifies the call-processing server, and the server bridges the calling party to the user on the second terminal.  
         [0017]     The illustrative embodiments of the present invention are advantageous over some techniques in the prior art for several reasons. First, the user is required to receive a first signal on one terminal and respond with a second signal on a different terminal. Second, in some embodiments the call-processing server transmits the first signal on the signaling channel and expects the user, by using the second terminal, to respond back on a different communications channel (e.g., a media channel, a circuit-switched channel, etc.). Third, in some embodiments the first signal that the call-processing server transmits is less easily read by machine (i.e., the first terminal) than the second signal that the server expects back from the user. By communicating the first and second signals across different terminals and different communications channels, as well as by considering the content of the signals, the illustrative embodiments lessen the ability of an adversary (e.g., through malware, etc.) to control the terminals.  
         [0018]     An illustrative embodiment of the present invention comprises: transmitting a first signal to a first telecommunications terminal; receiving at a server a second signal from a second telecommunications terminal; and determining whether or not to grant a privilege to the second telecommunications terminal based on the relationship of the first signal to the second signal; wherein the first telecommunications terminal and the second telecommunications terminal are physically distinct. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  depicts a block diagram of telecommunications system  100  in the prior art.  
         [0020]      FIG. 2  depicts a block diagram of telecommunications system  200  in accordance with the first illustrative embodiment of the present invention.  
         [0021]      FIG. 3  depicts a block diagram of the salient components of call-processing server  203 , in accordance with the first illustrative embodiment of the present invention.  
         [0022]      FIG. 4  depicts a first message-flow diagram of the salient events associated with determining whether or not to grant privileges to terminal  202 , in accordance with the first illustrative embodiment of the present invention.  
         [0023]      FIG. 5  depicts a second message-flow diagram of the salient events associated with determining whether or not to grant privileges to terminal  202 , in accordance with the first illustrative embodiment of the present invention.  
         [0024]      FIG. 6  depicts a block diagram of telecommunications system  600  in accordance with the second illustrative embodiment of the present invention.  
         [0025]      FIG. 7  depicts a block diagram of the salient components of call-processing server  603 , in accordance with the second illustrative embodiment of the present invention.  
         [0026]      FIG. 8  depicts a block diagram of the salient components of interactive voice response server  606 , in accordance with the second illustrative embodiment of the present invention.  
         [0027]      FIG. 9  depicts a message-flow diagram of the salient events associated with determining whether or not to grant privileges to terminal  602 , in accordance with the second illustrative embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0028]      FIG. 2  depicts a block diagram of telecommunications system  200  in accordance with the first illustrative embodiment of the present invention. Telecommunications system  200  comprises designating telecommunications terminal  201 , designated telecommunications terminal  202 , call-processing server  203 , and telecommunications network  204 , interconnected as shown.  
         [0029]     Designating telecommunications terminal  201  is a softphone, as is known in the art, which operates as a portable computer (e.g., a laptop, handheld personal digital assistant [PDA], etc.). Some of the telecommunications services that terminal  201  provides include placing and receiving calls, emailing, instant messaging, and so forth. Terminal  201  interacts with call-processing server  203  to initiate a session to provide a telecommunications service. In some embodiments, terminal  201  interacts with call-processing server  203  via a first communications channel (e.g., signaling channel  205 , etc.). For example, terminal  201  can be a signaling endpoint, as is known in the art. Terminal  201  communicates signaling information to call-processing server  203  via the Session Initiation Protocol (SIP). In some alternative embodiments, terminal  201  might communicate with call-processing server  203  via a different protocol (e.g., H.323, etc.).  
         [0030]     In some embodiments, once a session has been initiated, terminal  201  transmits via telecommunications network  204  session-related traffic, such as voice or data, in a packet format (e.g., via Internet Protocol, etc.) to one or more destinations. Terminal  201  might also receive session-related traffic from one or more sources via telecommunications network  204 .  
         [0031]     It will be clear to those skilled in the art how to make and use designating telecommunications terminal  201 .  
         [0032]     Designated telecommunications terminal  202  is a telecommunications terminal that is capable of placing and receiving calls, as well as exchanging traffic (e.g., voice, data, etc.) with other telecommunications terminals via network  204 . Terminal  202  is an Internet Protocol-capable terminal that transmits and receives packets of information. Terminal  202  is physically distinct from terminal  201  with an address (e.g., an Internet Protocol address, a telephone number identifier, etc.) different from that of terminal  201 , in accordance with the first illustrative embodiment. As part of an initiated session, terminal  202  transmits and receives traffic, via a second communications channel (e.g., media channel  206 , etc.) in some embodiments. For example, terminal  202  can be a media endpoint, as is known in the art. In some alternative embodiments, terminal  202  might be another type of terminal, such as a circuit-based terminal (e.g., a Plain Old Telephone Service wireline telephone, etc.). It will be clear to those skilled in the art how to make and use designated telecommunications terminal  202 .  
         [0033]     Call-processing server  203  is a data-processing system (e.g., at an office building, at a central office switching center, etc.) that is capable of exchanging signaling information and traffic with terminals  201  and  202 . Call-processing server  203 &#39;s interaction with terminals  201  and  202  is supported by telecommunications network  204 , which is equivalent to telecommunications network  104  and, as such, will not be described further. Moreover, call-processing server  203  enables a telecommunications user to designate a telecommunications terminal identifier, such as a telephone number (with or without an extension) or an Internet Protocol address, to which to extend an incoming call. The structure of call-processing server  203  is depicted in  FIG. 3 .  
         [0034]     In accordance with the first illustrative embodiment, call-processing server  203  is capable of exchanging messages to determine whether or not to grant one or more privileges to terminal  202 . The tasks that are related to call-processing server  203 &#39;s interaction with terminals  201  and  202  are described below and with respect to  FIGS. 4 and 5 . As those who are skilled in the art will appreciate, the functionality of determining whether or not to grant one or more privileges can be alternatively performed somewhere other than at call-processing server  203 .  
         [0035]     Some alternative embodiments might employ a private branch exchange, as is well-known in the art, in conjunction with call-processing server  203 . For example, the private branch exchange might be responsible for accommodating incoming and outgoing voice traffic, leaving call-processing server  203  to handle the specific interactions, described in this disclosure, with the signaling and media channels.  
         [0036]     It will be clear to those skilled in the art, after reading this disclosure, how to make and use call-processing server  203 .  
         [0037]      FIG. 3  depicts a block diagram of the salient components of call-processing server  203 , in accordance with the first illustrative embodiment of the present invention. Call-processing server  203  comprises network interface  301 , processor  302 , and memory  303 , interconnected as shown.  
         [0038]     Network interface  301  comprises a receiving part and a transmitting part. The receiving part receives signals from telecommunications network  204 , and forwards the information encoded in the signals to processor  302 , in well-known fashion. The transmitting part receives information from processor  302 , and outputs signals that encode this information to telecommunications network  204 , in well-known fashion. It will be clear to those skilled in the art how to make and use network interface  301 .  
         [0039]     Processor  302  is a general-purpose processor that is capable of: receiving information from network interface  301 ; reading data from and writing data into memory  303 ; executing the tasks described below and with respect to  FIGS. 4 and 5 ; and transmitting information to network interface  301 . In some alternative embodiments of the present invention, processor  302  might be a special-purpose processor. In either case, it will be clear to those skilled in the art, after reading this disclosure, how to make and use processor  302 .  
         [0040]     Memory  303  stores data and executable instructions, in well-known fashion, and is a combination of volatile and non-volatile memory. It will be clear to those skilled in the art how to make and use memory  303 .  
         [0041]      FIG. 4  depicts a first message-flow diagram of the salient events associated with determining whether or not to grant privileges to terminal  202 , in accordance with the first illustrative embodiment of the present invention. In this message flow, call-processing server  203  provides a first signal to terminal  201  and subsequently expects a second signal from terminal  202 . It will be clear to those skilled in the art which events depicted in  FIG. 4  can occur simultaneously or in a different order than that depicted.  
         [0042]     At event  401 , terminal  201  transmits to call-processing server  203  one or more messages that comprise (i) a registration and (ii) a designation of terminal  202  to be granted a privilege (e.g., serving as a media endpoint, etc.), in well-known fashion. For example, terminal  201 &#39;s user might want to conduct calls by using nearby terminal  202 , a telephone that is optimized for voice calls because terminal  202  offers better voice quality than the laptop that serves as terminal  201 .  
         [0043]     At task  402 , server  203  receives the designation of terminal  202  and determines whether or not to validate the relationship of terminals  201  and  202 . As those who are skilled in the art will appreciate, the validation can be performed unconditionally, periodically, sporadically, based on terminal  201 , based on terminal  202 , and so forth.  
         [0044]     At task  403 , upon deciding to validate the relationship of terminals  201  and  202 , server  203  transmits a first signal to terminal  201  on a first communications channel. In accordance with the first illustrative embodiment, the first communications channel is a signaling channel. The first signal comprises information that will be used to determine whether or not to grant privileges, such as allowing terminal  202  to be a media endpoint for future calls. In accordance with the first illustrative embodiment of the present invention, the first signal is less easily read by a machine (e.g., terminal  201 , etc.) than a second signal to be provided by the user through terminal  202 . For example, the first signal can comprise non-machine-readable information, such as that which is used for on-line registration or purchasing where a distorted or partially-obscured (but human-readable) image of a word is presented to the user, in well-known fashion; the user must then type in the word for verification. Server  203 , in some embodiments, also provides instructions via the signaling channel for the user of terminal  202  to follow. For example, text-based instructions might specify inputting, using the terminal  202 &#39;s keypad, the word that appears in the image presented to terminal  201 .  
         [0045]     Meanwhile, server  203  also initiates session  404  with terminal  202  in well-known fashion. At event  404 - 1 , server  203  alerts terminal  202  of the session being set up on a second communications channel. In accordance with the first illustrative embodiment, the second communications channel is a media channel. Server  203  also provides instructions on the media channel for the user of terminal  202  to follow. For example, the audio-based instructions might specify inputting, using the terminal  202 &#39;s keypad, the word that appears in the image presented to terminal  201 .  
         [0046]     At event  404 - 2 , terminal  202  transmits on the media channel a second signal. The second signal comprises information provided by the user at terminal  202 . For example, if the first signal received by terminal  201  comprises a distorted image of the word “elephant”, the user of terminal  202  would indicate (e.g., via terminal  202 &#39;s keypad, via speaking into terminal  202 &#39;s microphone, etc.) that the received word is “elephant”. If the user enters a response via the keypad, terminal  202  transmits the second signal as one or more dual tone multi-frequency signals (i.e., “touch tones”).  
         [0047]     At task  405 , server  203  receives the second signal in well-known fashion. In accordance with the first illustrative embodiment of the present invention, server  203  then determines whether or not to grant one or more privileges to terminal  202  based on the relationship of the first signal to the second signal. Continuing with the example presented above, if the transmitted first signal comprises an image of the word “elephant” and the received second signal comprises an indication that the terminal  202 &#39;s user understood the word to be “elephant”, then server  203  grants the privilege, such as allowing terminal  202  to place calls or to receive calls, or both. If, however, the received second signal indicates an incorrect word or if no second signal was received, then server  203  does not grant the privilege.  
         [0048]      FIG. 5  depicts a second message-flow diagram of the salient events associated with determining whether or not to grant privileges to terminal  202 , in accordance with the first illustrative embodiment of the present invention. In this message flow, call-processing server  203  provides a first signal to terminal  202  and subsequently expects a second signal from terminal  201 . It will be clear to those skilled in the art which events depicted in  FIG. 5  can occur simultaneously or in a different order than that depicted.  
         [0049]     At event  501 , terminal  201  transmits to call-processing server  203  one or more messages that comprise (i) a registration and (ii) a designation of terminal  202  to be granted a privilege (e.g., serving as a media endpoint, etc.), in well-known fashion. For example, terminal  201 &#39;s user might want to conduct calls by using nearby terminal  202 , a telephone that is optimized for voice calls because terminal  202  offers better voice quality than the laptop that serves as terminal  201 .  
         [0050]     At task  502 , server  203  receives the designation of terminal  202  and determines whether or not to validate the relationship of terminals  201  and  202 . As those who are skilled in the art will appreciate, the validation can be performed unconditionally, periodically, sporadically, based on terminal  201 , based on terminal  202 , and so forth.  
         [0051]     At task  503 , upon deciding to validate the relationship of terminals  201  and  202 , server  203  initiates session  503  with terminal  202  in well-known fashion. At event  503 - 1 , server  203  alerts terminal  202  of the session being set up on a media channel. Server  203  also provides instructions on the media channel for the user of terminal  202  to follow.  
         [0052]     At event  503 - 2 , server  203  then transmits a first signal to terminal  202  on the media channel. The first signal comprises information that will be used to determine whether or not to grant privileges, such as allowing terminal  202  to be a media endpoint for future calls.  
         [0053]     At event  504 , terminal  201  transmits on the signaling channel a second signal. The second signal comprises information provided by the user of terminals  201  and  202 . For example, if the first signal received by terminal  202  comprises a distorted image of the word “elephant”, the user of terminal  201  would indicate (e.g., via terminal  201 &#39;s laptop keyboard, etc.) that the received word is “elephant”.  
         [0054]     At task  505 , server  203  receives the second signal in well-known fashion. In accordance with the first illustrative embodiment of the present invention, server  203  then determines whether or not to grant one or more privileges to terminal  202  based on the relationship of the first signal to the second signal. Continuing with the example presented above, if the transmitted first signal comprises an image of the word “elephant” and the received second signal comprises an indication that the terminal  202 &#39;s user understood the word to be “elephant”, then server  203  grants the privilege, such as allowing terminal  202  to place calls or to receive calls, or both. If, however, the received second signal indicates an incorrect word or if no second signal was received, then server  203  does not grant the privilege.  
         [0055]      FIG. 6  depicts a block diagram of telecommunications system  600  in accordance with the second illustrative embodiment of the present invention. Telecommunications system  600  comprises designating telecommunications terminal  601 , designated telecommunications terminal  602 , call-processing server  603 , telecommunications network  604 , calling telecommunications terminal  605 , interactive voice response server  606 , and switching system  607 , interconnected as shown.  
         [0056]     Designating telecommunications terminal  601  is a softphone, as is known in the art, which operates as a portable computer (e.g., a laptop, handheld personal digital assistant [PDA], etc.). Some of the telecommunications services that terminal  601  provides include placing and receiving calls, emailing, instant messaging, and so forth. Terminal  601  interacts with call-processing server  603  to initiate a session to provide a telecommunications service. In some embodiments, terminal  601  interacts with call-processing server  603  via a signaling channel (e.g., signaling channel  605 , etc.). For example, terminal  601  can be a signaling endpoint, as is known in the art. Terminal  601  communicates signaling information to call-processing server  603  via the Session Initiation Protocol (SIP). In some alternative embodiments, terminal  601  might communicate with call-processing server  603  via a different protocol (e.g., H.323, etc.).  
         [0057]     In some embodiments, once a session has been initiated, terminal  601  transmits via telecommunications network  604  session-related traffic, such as voice or data, in a packet format (e.g., via Internet Protocol, etc.) to one or more destinations. Terminal  601  might also receive session-related traffic from one or more sources via telecommunications network  604 .  
         [0058]     It will be clear to those skilled in the art how to make and use designating telecommunications terminal  601 .  
         [0059]     Designated telecommunications terminal  602  is a telecommunications terminal that is capable of placing and receiving calls, as well as exchanging traffic (e.g., voice, data, etc.) with other telecommunications terminals via switching system  607  and network  604 . Terminal  602  is an Internet Protocol-capable terminal that transmits and receives packets of information. Terminal  602  is physically distinct from terminal  601  with an address (e.g., an Internet Protocol address, a telephone number identifier, etc.) different from that of terminal  601 , in accordance with the first illustrative embodiment. As part of an initiated session, terminal  602  transmits and receives traffic, via a media channel (e.g., media channel  606 , etc.) in some embodiments. For example, terminal  602  can be a media endpoint, as is known in the art. In some alternative embodiments, terminal  602  might be another type of terminal, such as a circuit-based terminal (e.g., a Plain Old Telephone Service wireline telephone, etc.). It will be clear to those skilled in the art how to make and use designated telecommunications terminal  602 .  
         [0060]     Call-processing server  603  is a data-processing system (e.g., at an office building, at a central office switching center, etc.) that is capable of exchanging signaling information and traffic with terminals  601  and  602 . Call-processing server  603 &#39;s interaction with terminals  601  and  602  is supported by telecommunications network  604 , which is equivalent to telecommunications network  104  and, as such, will not be described further. Call-processing server  603  is also capable of exchanging signaling information and traffic with interactive voice response server  606  via network  604 , in well-known fashion. Moreover, call-processing server  603  enables a telecommunications user to designate a telecommunications terminal identifier, such as a telephone number (with or without an extension) or an Internet Protocol address, to which to extend an incoming call. The structure of call-processing server  603  is depicted in  FIG. 7 .  
         [0061]     In accordance with the second illustrative embodiment, call-processing server  603  is capable of exchanging messages to determine whether or not to grant one or more privileges to terminal  602 . The tasks that are related to call-processing server  603 &#39;s interaction with terminals  601  and  602  are described below and with respect to  FIG. 9 . As those who are skilled in the art will appreciate, the functionality of determining whether or not to grant one or more privileges can be alternatively performed somewhere other than call-processing server  603 .  
         [0062]     Some alternative embodiments might employ a private branch exchange, as is well-known in the art, in conjunction with call-processing server  603 . For example, the private branch exchange might be responsible for accommodating incoming and outgoing voice traffic, leaving call-processing server  603  to handle specific interactions, described in this disclosure, with the signaling and media channels.  
         [0063]     It will be clear to those skilled in the art, after reading this disclosure, how to make and use call-processing server  603 .  
         [0064]     Calling telecommunications terminal  605  is capable of placing a call to a user, such as the user of terminal  601 , in well-known fashion. It will be clear to those skilled in the art how to make and use terminal  605 .  
         [0065]     Interactive voice response (IVR) server  606  is a system that provides interactive voice response capability, in well-known fashion. IVR server  606  receives signaling information and voice traffic for the purpose of interacting (e.g., receiving selections, etc.) with a person, such as a telecommunications terminal user or a telephone operator associated with switching system  607 . IVR server  606  presents one or more menus or announcements to the person and receives input from the person (e.g., speech signals, keypad input, etc.). IVR server  606  transmits data back to call-processing server  603  in response to and based on the received selections, in accordance with the second illustrative embodiment of the present invention. It will be clear to those skilled in the art, after reading this disclosure, how to make and use interactive voice response server  606 .  
         [0066]     Switching system  607  handles incoming and outgoing calls for a particular facility (e.g., a hotel building, etc.) and for one or more telecommunications terminals at that facility (e.g., terminal  602 , etc.). In accordance with the second illustrative embodiment of the present invention, switching system  607  is a private branch exchange with a switchboard that is staffed by an operator. In some alternative embodiments, switching system  607  is a private branch exchange that automatically switches calls. It will be clear to those skilled in the art how to make and use switching system  607 .  
         [0067]      FIG. 7  depicts a block diagram of the salient components of call-processing server  603 , in accordance with the second illustrative embodiment of the present invention. Call-processing server  603  comprises network interface  701 , processor  702 , and memory  703 , interconnected as shown.  
         [0068]     Network interface  701  comprises a receiving part and a transmitting part. The receiving part receives signals from telecommunications network  604 , and forwards the information encoded in the signals to processor  702 , in well-known fashion. The transmitting part receives information from processor  702 , and outputs signals that encode this information to telecommunications network  604 , in well-known fashion. It will be clear to those skilled in the art how to make and use network interface  701 .  
         [0069]     Processor  702  is a general-purpose processor that is capable of: receiving information from network interface  701 ; reading data from and writing data into memory  703 ; executing the tasks described below and with respect to  FIG. 9 ; and transmitting information to network interface  701 . In some alternative embodiments of the present invention, processor  702  might be a special-purpose processor. In either case, it will be clear to those skilled in the art, after reading this disclosure, how to make and use processor  702 .  
         [0070]     Memory  703  stores data and executable instructions, in well-known fashion, and is a combination of volatile and non-volatile memory. It will be clear to those skilled in the art how to make and use memory  703 .  
         [0071]      FIG. 8  depicts a block diagram of the salient components of interactive voice response server  606 , in accordance with the second illustrative embodiment of the present invention. Interactive voice response server  606  comprises network interface  801 , processor  802 , and memory  803 , interconnected as shown.  
         [0072]     Network interface  801  comprises a receiving part and a transmitting part. The receiving part receives signals from telecommunications network  604 , and forwards the information encoded in the signals to processor  802 , in well-known fashion. The transmitting part receives information from processor  802 , and outputs signals that encode this information to telecommunications network  604 , in well-known fashion. It will be clear to those skilled in the art how to make and use network interface  801 .  
         [0073]     Processor  802  is a general-purpose processor that is capable of: receiving information from network interface  801 ; reading data from and writing data into memory  803 ; executing the tasks described below and with respect to  FIG. 9 ; and transmitting information to network interface  801 . In some alternative embodiments of the present invention, processor  802  might be a special-purpose processor. In either case, it will be clear to those skilled in the art, after reading this disclosure, how to make and use processor  802 .  
         [0074]     Memory  803  stores data and executable instructions, in well-known fashion, and is a combination of volatile and non-volatile memory. It will be clear to those skilled in the art how to make and use memory  803 .  
         [0075]      FIG. 9  depicts a message-flow diagram of the salient events associated with determining whether or not to grant privileges to terminal  602 , in accordance with the second illustrative embodiment of the present invention. It will be clear to those skilled in the art which events depicted in  FIG. 9  can occur simultaneously or in a different order than that depicted.  
         [0076]     In the example that is depicted in  FIG. 9 , a telecommunications user has the capability through call-processing server  603  to have calls that are made to her office telephone number extended to a designated telephone number or other address (e.g., an Internet Protocol address, etc.) outside the office. In this example, the user is currently staying at a hotel and wishes to designate the telephone in her hotel room to receive the calls that are made to her office telephone number. The room telephone, however, does not have a directly dialed number; instead, all incoming calls to the room telephone have to be switched through by the hotel operator. The user has brought along her laptop, which supports a softphone function and is represented in  FIG. 9  as terminal  601 . Terminal  601  is able to communicate in part via the hotel&#39;s local area network (e.g., a WiFi network, etc.). Terminal  602  represents the room telephone. Call-processing server  603  is the data-processing system that serves the office building at which the user works, including her office telephone. Interactive voice response server  606  is also associated with server  603  and the office building.  
         [0077]     At event  901 , terminal  601  transmits to call-processing server  603  one or more messages that comprise (i) a registration and (ii) a designation of terminal  602  to be granted a privilege (e.g., serving as a media endpoint, etc.), in well-known fashion. The designation of terminal  602  comprises: (i) a telephone number (e.g., a 10-digit number in North America, etc.) that routes to the hotel private branch exchange, and (ii) an extension that corresponds to the particular room phone at the hotel. Terminal  601 &#39;s user invokes this message flow to conduct calls by using nearby terminal  602 , a hotel room telephone that is optimized for voice calls and that offers better voice quality than her laptop softphone of terminal  601 .  
         [0078]     At event  902 , which occurs independently of event  901  and possibly hours later, calling telecommunications terminal  605  places a call to the office telephone number of terminal  602 &#39;s user. As a result, the call is routed to call-processing server  603 , in well-known fashion.  
         [0079]     At task  903 , server  603  receives the incoming call, checks the user&#39;s database, and determines that the user has specified a telephone number and extension that corresponds to terminal  602  and that requires hotel operator intervention. Because the incoming call is intended for terminal  602 , server  603  decides to validate the relationship of terminals  601  and  602 . It will be clear to those skilled in the art how to determine when to validate the relationship of the two terminals, as described earlier and with respect to  FIGS. 4 and 5 .  
         [0080]     At event  904 , upon deciding to validate the relationship of terminals  601  and  602 , server  603  transmits a first signal to terminal  601  on a first communications channel. In accordance with the second illustrative embodiment, the first communications channel is a signaling channel. The first signal comprises information that will be used to determine whether or not to grant privileges, such as allowing terminal  602  to be a media endpoint for future calls to the user. In accordance with the second illustrative embodiment of the present invention, the first signal is less easily read by a machine (e.g., terminal  601 , etc.) than a second signal to be provided by the user at terminal  602 , as described earlier and with respect to task  403  of  FIG. 4 . Server  603  also provides instructions via the signaling channel for the user to follow.  
         [0081]     In some alternative embodiments, the first signal might be easily read by a machine. For example, in some applications securing terminal  601  from malware or from the effects of malware might not be an issue or might be accomplished through other means.  
         [0082]     Meanwhile, at event  905  call-processing server  603  also transmits to IVR server  606 : (i) the telephone number of the hotel, (ii) the room extension, and (iii) the first signal.  
         [0083]     At task  906 , IVR server  606  calls switching system  607  in well-known fashion by using the telephone number of the hotel that was provided by call-processing server  603 .  
         [0084]     At event  907 , IVR server  606  announces to the hotel operator at switching system  607  that there is an incoming call and provides the hotel operator with the room extension.  
         [0085]     At event  908 , switching system  607  alerts terminal  602  of an incoming call. The user of terminal  602  answers the call.  
         [0086]     At event  909 , IVR server  606  provides instructions (e.g., audio-based, etc.) for the user of terminal  602  to follow. For example, the instructions might specify inputting, using the terminal  602 &#39;s keypad, the information provided as part of the first signal transmitted previously to terminal  601 .  
         [0087]     At event  910 , terminal  602  transmits on a second communications channel a second signal. In accordance with the second illustrative embodiment, the second communications channel is a media channel. The second signal comprises information provided by the user of terminals  601  and  602 . For example, if the first signal received by terminal  601  comprises a distorted image of the word “elephant”, the user of terminal  602  would indicate (e.g., via terminal  602 &#39;s keypad, via speaking into terminal  602 &#39;s microphone, etc.) that the received word is “elephant”. If the user enters a response via the keypad, terminal  602  transmits the second signal as one or more dual tone multi-frequency signals (i.e., “touch tones”).  
         [0088]     At task  911 , IVR server  606  receives the second signal in well-known fashion. In accordance with the second illustrative embodiment of the present invention, IVR server  606  then determines whether or not the relationship of the first signal (and terminal  601 ) to the second signal (and terminal  602 ) is valid. Continuing with the example presented earlier, if the transmitted first signal comprises an image of the word “elephant” and the received second signal comprises an indication that the terminal  602 &#39;s user understood the word to be “elephant”, then IVR server  606  determines the relationship to be valid and removes itself from the call flow. If, however, the received second signal indicates an incorrect word or if no second signal was received, then server  603  determines the relationship to be invalid.  
         [0089]     At event  912 , IVR server  606  notifies call-processing server  603  of the success or failure in validating the relationship between terminals  601  and  602 .  
         [0090]     At task  913 , call-processing server  603  decides whether or not to allow the call through to terminal  602 , based on the validation of the relationship between terminals  601  and  602 .  
         [0091]     At event  914 , call-processing server  603  allows the call through to terminal  602  if the relationship between the two terminals has been validated.  
         [0092]     As will be appreciated by those skilled in the art, although the second illustrative embodiment of the present invention employs both call-processing server  603  and interactive voice response (IVR) server  606 , some alternative embodiments might employ only one of processing server  603  and IVR server  606 , with the capability of performing the methods depicted in  FIG. 9 .  
         [0093]     Furthermore, as will be appreciated by those skilled in the art, some embodiments that are alternative to the illustrative embodiments might also employ a private branch exchange (or other data-processing system) to perform the methods depicted in  FIGS. 4, 5 , and  9 . Some other alternative embodiments might employ a private branch exchange to perform the methods depicted in  FIGS. 4, 5 , and  9  without one or any of call-processing server  203 / 603  and IVR server  606 .  
         [0094]     It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. For example, in this Disclosure, numerous specific details are provided in order to provide a thorough description and understanding of the illustrative embodiments of the present invention. Those skilled in the art will recognize, however, that the invention can be practiced without one or more of those details, or with other methods, materials, components, etc.  
         [0095]     Furthermore, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the illustrative embodiments. It is understood that the various embodiments shown in the Figures are illustrative, and are not necessarily drawn to scale. Reference throughout the disclosure to “one embodiment” or “an embodiment” or “some embodiments” means that a particular feature, structure, material, or characteristic described in connection with the embodiment(s) is included in at least one embodiment of the present invention, but not necessarily all embodiments. Consequently, the appearances of the phrase “in one embodiment,” “in an embodiment,” or “in some embodiments” in various places throughout the Disclosure are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.