Patent Publication Number: US-2007116213-A1

Title: Methods and apparatus to detect and block unwanted fax calls

Description:
FIELD OF THE DISCLOSURE  
      This disclosure relates generally to facsimile communications (faxes), and, more particularly, to methods and apparatus to detect and block unwanted fax calls.  
     BACKGROUND  
      Fax machines in businesses or personal residences typically require a shared or dedicated telephone line, ink toner, and paper stock for proper operation. The fax machine consumes all three of these resources during operation. That is, the fax machine occupies the telephone line and deposits ink toner on paper stock to receive and communicate fax information to a user.  
      Nuisance and unsolicited commercial faxes are those that the user, employee, or homeowner does not want to receive. Examples of such nuisance faxes include unwanted sales brochures and marketing surveys in which the unwanted fax transmissions tie-up the dedicated or shared telephone line and consume ink toner and paper stock. Individuals and organizations (hereinafter fax-marketers and/or callers to be blocked) that forward such nuisance faxes often employ a tactic known as “war-dialing” to discover and use fax machines connected to a dedicated telephone line as a method to push their sales and marketing information. War-dialing includes simultaneously calling numerically consecutive blocks of destination telephone numbers, typically from several originating telephone lines, with the objective of finding at least some fax machines at those numerically consecutive destination numbers. War dialing may include simultaneously calling a block of numbers, sequentially calling numerically consecutive numbers, and/or sequentially calling blocks of numbers. War-dialing is particularly successful for fax-marketers targeting mid to large size businesses that allocate a bank of numerically consecutive telephone numbers (lines) dedicated to fax machines in various locations throughout that business.  
      Although the fax-marketers do not know which, if any, of the dialed numbers will reach a functional fax machine, those numbers that answer with fax handshaking tones will establish a connection and receive the nuisance fax information. The nuisance fax information thus unnecessarily consumes ink toner, paper stock, and ties-up the telephone line of the receiving party during transmission. Additionally, such fax-marketing techniques present irritating fax-tones to people that answer a ringing telephone line with a telephone. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic diagram illustrating an example fax-blocker constructed in accordance with the teachings of the invention and shown in an example send/receive environment.  
       FIG. 2 ( a ) is a diagram illustrating an example war-dialing technique which may be immediately detected by the example fax-blocker of  FIGS. 1 and 3 .  
       FIG. 2 ( b ) is a diagram illustrating an example war-dialing technique which may be determined through records analysis by the example fax-blocker of  FIGS. 1 and 3 .  
       FIG. 3  is a schematic diagram illustrating further details of the example fax-blocker of  FIG. 1 .  
       FIG. 4  illustrates an example data structure which may be created for each originating fax caller.  
      FIGS.  5 ( a )- 5 ( b ) are flow charts representative of example machine readable instructions which may be executed to implement the example fax blocker shown in  FIG. 1  and  FIG. 3 .  
       FIG. 6  is a schematic illustration of an example computer which may execute the programs of FIGS.  5 ( a ) and  5 ( b ) to implement the fax-blocker of  FIG. 1  and  FIG. 3 . 
    
    
     DETAILED DESCRIPTION  
      Methods and apparatus to detect and block unwanted fax calls are disclosed. An example method includes detecting a fax call associated with a calling number, blocking the fax call if the calling number is associated with a caller to be blocked identified in a database, and attempting to identify a presence of a war-dialing technique. An example apparatus includes a pattern-trap to identify originating phone numbers exhibiting a calling pattern indicative of fax-marketing. The apparatus may include a fax-originator database to store identities of callers to be blocked, and a fax-originator detector in communication with the fax-originator database to determine if a fax call should be blocked.  
      An example telecommunications network  100  is shown in  FIG. 1 . As mentioned above, a fax-marketer may generate a list of sequential telephone numbers to call when searching for fax machines. To this end, the fax-marketer gains access to any standard telecommunications network through a first telecommunications node (Telco Node)  120  and one or more telephone lines. The Telco Node  120  is also referred-to as a service switching point (SSP) or a signal switching point. Additionally, the Telco Node or SSP may be referred to as an end office (EO). Although in the following description the network  100  is an advanced intelligent network (AIN) operation in accordance with the Signaling System  7  (SS 7 ) protocol, persons of ordinary skill in the art will appreciate that other types of telecommunication networks are also applicable.  
      Telecommunication companies may use an Intelligent Peripheral and/or Service Node (IP/SN) device or devices to manage the flow of communications between telephone/fax callers and receivers. IP/SN devices  130  may provide routing and/or control services in conjunction with the AIN  100 . IP/SN devices  130  are flexible devices in that they may be programmed to perform specific tasks and functionality with any compatible network  100 . IP/SN devices  130  are sometimes referred to as Compact Service Nodes (CSN), eMRS and RM devices, as is well known to those having ordinary skill in the art of telecommunication networks.  
      Telephone and/or fax calls made by a fax-marketer are routed to the Telco Node  230 , which queries an AIN signal control point (SCP)  140  via a signal transfer point (STP)  150 . The STP  150  is a packet switch that shuttles messages between the SSP  120  and the SCP  140 . The SCP  140  is a remote database to, in part, supply translation and routing data for delivering advanced network services. The SCP  140  may provide, for example, instructions on how a call should be routed. Calls without routing instructions in the SCP  140  may further be screened through the IP/SN  130  for further instructions. Instructions from either the SCP  140  or the IP/SN  130  are routed back to the Telco Node  120  to accommodate the call, from which those calls branch-out to localized telecommunication devices, such as telephones and fax machines. As will be discussed in further detail below, a fax-blocker  195  of the IP/SN  130  provides, in part, real time call screening.  
      A list of numerically consecutive numbers  160  to dial is sometimes referred to as a war-dialing list. If a fax-marketer initiates a calling strategy with the list of numerically consecutive numbers  160 , the telecommunications network  100  may accommodate that request by connecting the calling party (e.g., the fax-marketer) with the corresponding people or devices with which the called telephone number is associated  165  (e.g., a person answering a voice telephone, a private fax machine, one or more fax machines in a business, etc.). For example, the first two numerically consecutive numbers  170  dialed by the fax-marketer may correspond to a small business with two fax machines while the third number  180  may correspond to a single fax machine in the same small business, in another business, or in a person&#39;s home. Additionally, other numbers  190  dialed by the fax-marketer may correspond to a voice telephone number, resulting in annoying fax-tones presented to an ear of the called party.  
      In the illustrated example, a fax-blocker  195  is provided at the IP/SN  130  to detect fax calls, automatically identify fax marketers and/or their calling behavior, determine if a fax call originates from a caller to be blocked (e.g., a fax-marketer), and block fax call attempts by that caller if the called terminating number(s) are associated with a subscriber to the fax-blocking service. The caller to be blocked may include originating callers exhibiting war-dialing behavior, and/or a focused business having an objective to discover fax destination numbers. For ease of reference, the callers to be blocked and the fax-marketers will be referred to as “fax-marketers.” To this end, the illustrated example fax-blocker  195  maintains a database of known or suspected fax-marketers, fax-originators, and/or originating callers for the benefit of users that subscribe to a blocking service. In addition to, or in lieu of subscribers realizing a benefit from the blocking service, such blocking services may be provided to other customers and/or third parties. For example, the blocking services may be extended to potential customers as an incentive, and/or extended to existing customers as a promotion free of charge.  
      The fax-blocker database may grow with new numbers as the fax-blocker  195  identifies additional fax-marketers based on their calling behavior. Although fax-marketers may compile lists of known fax machines (e.g., from business cards, web sites, phone books, etc.), war-dialing techniques are primarily employed by the fax-marketers to determine fax machines on unadvertised and undisclosed destination numbers. A subscriber may use the database established by the fax-blocker  195  as-is, or alternately, may customize a personalized blocking list to work with the fax-blocker database based on their preferences.  
      An example scenario in which a subscriber may choose to personalize a blocking list is when a subscriber wants to maintain blocking functionality for most of the identified fax-marketers in the fax-blocker database, yet allow faxes from one or more specific entries within that database. For example, consider the situation when an originating caller is identified by the fax-blocker  195  as a potential fax-marketer due to the originating caller making simultaneous fax transmissions to numerically consecutive numbers or the originating caller making fax transmissions in a pattern consistent with fax-marketing. The behavior of this caller fits a “nuisance faxer” characterization and, thus, in the course of time the number exhibiting this behavior would be identified as a fax-marketer and their faxes would ordinarily be blocked for subscribers of the fax blocking service. However, if these originating calls are from one department of a business communicating inter-office memos to various other parts of that same business, the originating fax caller may be a legitimate fax caller for the subscriber (i.e., for the parts of the same business) and, thus, the subscriber would like to personalize the blocking list to permit fax calls from this caller.  
      Although the example fax-blocker  195  is shown located at an IP/SN  130 , persons of ordinary skill in the art will readily appreciate that one or more fax-blocker(s)  195  may be located at any other desired location(s) in the network  100 . For example, the fax-blocker  195  may be associated with the IP/SN  130 , associated with a signal control point (SCP), and/or associated with a feature/media server. Additionally or alternatively, the fax-blocker  195  may be integrated into an existing structure in the network (e.g., an IP/SN, an SCP, an STP, etc.), may be coupled to an existing structure in the network (e.g., an IP/SN, an SCP, an STP, etc.), and/or may be a stand alone unit. If the IP/SN  130  provides fax-tone detection services, the IP/SN  130  may automatically invoke the fax-blocker  195  only when needed (i.e., upon detection of a fax call), thereby conserving processing resources of the fax-blocker  195 . Alternatively, the fax-blocker  195  may employ its own fax-tone detection services, as will be discussed later.  
      FIGS.  2 ( a ) and  2 ( b ) graphically illustrate various techniques that fax-marketers may employ when searching for available fax machines (war-dialing). Generally speaking,  FIG. 2 ( a ) illustrates a war-dialing technique that the fax-blocker  195  may immediately detect, whereas  FIG. 2 ( b ) illustrates a war dialing technique that may be detected after post-fax transmission analysis, as will be discussed later.  
      Referring first to  FIG. 2 ( a ), some fax-marketers may originate their war dialing techniques by using several originating telephone/fax lines, such as line  1  ( 202 ), line  2  ( 204 ) and line  3  ( 206 ). Each of these lines may be a standard telephone line having a fax machine, or similar fax transmission device connected thereto.  FIG. 2 ( a ) further illustrates line  1  having an originating number of 555-1212, line  2  having an originating number of 555-1213, and line  3  having an originating number of 555-1214. While a numerically consecutive block of telephone lines is typically assigned by a telephone company to a residence or business, a fax-marketer may also employ several lines having non-consecutive and/or arbitrary originating numbers. Although the above example illustrates a fax-marketer using a plurality of originating lines, persons of ordinary skill in the art will appreciate that a fax-marketer may employ devices that can simultaneously place numerous calls from the same originating telephone line. Such devices may effectively hide the caller identification (caller-ID), or replace such caller-ID with a number unassociated with the actual originating telephone line. Each of lines  1 ,  2 , and  3  may, at a time “t 1 ,” call a numerically consecutive block of destination numbers. In particular, at time “t 1 ” line  1  calls destination number 555-1111 ( 208 ), line  2  calls destination number 555-1112 ( 210 ), and line  3  calls destination number 555-1113 ( 212 ). If any of the destination numbers happen to be a fax machine/device, the fax-marketer proceeds to transmit the unsolicited fax information. The fax-marketer may repeat this process at time “t 2 ” where a new group of numerically consecutive destination numbers is called to search for fax machines/devices. For example, at time “t 2 ” line  1  calls destination number 555-1114 ( 214 ), line  2  calls destination number 555-1115 ( 216 ), and line  3  calls destination number 555-1116 ( 218 ). Similarly, the fax-marketer may repeat this process at time “t n ” in a similar manner with additional numerically consecutive destination numbers “n 1 ,”  220  n 2 ,”  222  and “n 3 ”  224 . In another example, each of lines  1 ,  2 , and  3  may, at time “t 1 ” call a numerically consecutive block of destination numbers, as described earlier. However, if only line  2  happens to establish a connection with a fax machine, (e.g., destination number 555-1112 ( 210 )) and the destination numbers dialed by lines  1  and  3  are inoperative or not associated with a fax machine, then lines  1  and  3  may immediately proceed call destination numbers 555-1114 ( 214 ) and 555-1116 ( 218 ), respectively. In other words, lines  1  and  3  continue to hunt for additional fax machines while line  2  finishes sending fax-marketing information to the destination number it called at time “t 1 .” The fax-marketer, thus, “staggers” such war dialing behavior so that destination numbers not associated with a fax machine do not sit dormant while waiting for another destination line to complete receipt of the nuisance fax information.  
      When a numerically consecutive pattern (i.e., consecutive originating numbers called substantially in parallel, but not, for example, to the possible staggering noted above) is detected at any particular time period (e.g., “t 1 ,” “t 2 ,” through “t n ,”), the fax-blocker  195  may assume that the originating numbers are all associated with each other for the purpose of war dialing. Such an assumption allows the fax-blocker  195  to identify those originating numbers as fax-marketers in a single time period (i.e., immediately). A user of the fax-blocker  195  may find such an assumption reasonable given the remote possibility that unrelated originating numbers (e.g., originating numbers not owned or operated by single entity for the purpose of unsolicited fax solicitation) substantially simultaneously dial a numerically consecutive group of destination numbers. Alternatively, or additionally, the fax-blocker  195  may search one or more databases of the telecommunications network  100  to determine if such originating numbers are associated with a common entity.  
       FIG. 2 ( b ) illustrates an alternate fax-marketing technique employed by a fax-marketer who may be aware of pattern detection techniques employed to thwart their nuisance marketing efforts. Similar to  FIG. 2 ( a ),  FIG. 2 ( b ) illustrates a fax-marketer with several originating fax lines, such as line  1  ( 232 ) having an originating number of 555-1212, line  2  ( 234 ) having an originating number of 555-1213, and line  3  ( 236 ) having an originating number of 555-1214. Each of these originating lines may be either independently owned/operated, or owned by a single fax-marketer to collaboratively hunt for a greater number of fax machines at destination numbers in a shorter period of time. At time “t 1 ,” destination number 555-1111 ( 238 ), destination number 555-2555 ( 240 ), and destination number 555-7121 ( 242 ) may be simultaneously called by the fax-marketer, or such calls may be made by fax-marketers unrelated to one another. Because the called numbers at time “t 1  ” are not numerically consecutive, the destination numbers do not immediately appear to exhibit a calling pattern at that time. As such, detection of a fax-marketer is accomplished through an analysis over a time period. For example, at time “t 2 ,” the fax-marketer calls each one of destination number 555-1112 ( 244 ) with originating line  1  ( 232 ), destination number 555-2556 ( 246 ) with originating line  2  ( 234 ), and destination number 555-7122 ( 248 ) with originating line  3  ( 236 ). An analysis of destination numbers between times “t 1 ” and “t 2 ” now reveals an emerging pattern of a numerically consecutive calling behavior for each of originating lines  1 ,  2 , and  3 . The fax-blocker  195  may deem each of the originating lines as potential fax-marketers when a suspected threshold  262  (in this example, two) of numerically consecutive calls is observed. Employing the suspected threshold  262  accommodates for circumstances in which a caller accidentally misdials a number by one digit. Rather than immediately add that originating caller&#39;s number to the fax-blocker database in light of an innocent mistake, the originating number is merely recorded/flagged as “suspected.” However, as shown at time “t 3 ,” each of originating lines  1 ,  2 , and  3  respectively place calls to destination numbers 555-1113 ( 250 ), 555-2557 ( 252 ), and 555-7123 ( 254 ). As each of these three destination numbers is numerically consecutive from the previous call placed by the corresponding originating number at time “t 2 ,” the fax-blocker  195  flags each of these originating numbers as fax-marketers because a confirmed threshold  264  (e.g., three numerically consecutive calls) has been exceeded. Consequently, those fax-marketer numbers are added to the fax-blocker database. In the event any of the fax-marketers, whether they are related or not, attempts to call destination numbers “n 1 ,”  256  “n 2 ,”  258  or “n 3 ”  260  at time “t n ” or thereafter, the fax-blocker  195  will block the fax call if the customer associated with destination number “n 1 ,” “n 2 ,” or “n 3 ” is a subscriber to the fax-blocking service.  
      Although the above example illustrates a suspected threshold  262  set at two numerically consecutive calls, and the confirmed threshold  264  set at three numerically consecutive calls by an originating line, persons of ordinary skill in the art will appreciate that such thresholds may be set at any desired number of calls. Further, while the above example illustrates the confirmed threshold  264  placed at a time interval immediately after the time interval associated with the suspected threshold  262 , persons of ordinary skill in the art will appreciate that the confirmed threshold  264  could be placed several time intervals away from the suspected threshold  262 . For example, the confirmed threshold  264  may alternatively be set such that if the suspected fax-marketer associated with originating line  1  ( 232 ) places an additional fax call to the destination number 555-1113 ( 250 ) at any time within a predetermined time period (e.g., 2 hours, 2 days, 2 weeks, etc.), originating line  1  ( 232 ) will be added to the fax-blocker database for future blocking for at least a predetermined time period.  
      Although FIGS.  2 ( a ) (immediate war-dialing detection) and  2 ( b ) (war-dialing detection following post-fax analysis) illustrate two possible war-dialing techniques that a fax-marketer may employ and that may be detected by the fax-blocker  195 , this list is not exhaustive and the fax-blocker  195  may be structured to identify and block other techniques and/or behaviors characteristic of fax-marketing.  
       FIG. 3  is a more detailed schematic illustration of the example fax-blocker  195  of  FIG. 1 . In the example of  FIG. 3 , the fax-blocker  195  cooperates with an IP/SN  130 . Thus, when the IP/SN  130  receives a message to assist in routing a call, it delivers the originating number and the destination number for that call to the fax-blocker  195  to determine if the call should be blocked. In order to identify fax calls, the fax-blocker  195  of the example of  FIG. 3  includes a fax-tone detector  310 . The fax-tone detector  310  monitors signals on a monitored telephone line or on a plurality of monitored telephone lines to determine which, if any, of the calls being handled by those line(s) are fax calls. Fax calls can be detected by, for example, identifying the presence of fax tones used in the handshaking process of facsimile protocols to establish a fax transmission. Although the fax-blocker  195  example of  FIG. 3  includes a fax-tone detector  310 , persons of ordinary skill in the art will appreciate that the fax-blocker  195  may, alternatively, employ the services of the IP/SN  130  to detect fax-tones. When calls including fax-tones are detected by the IP/SN  130 , such calls may be forwarded to the fax-blocker  195  for further analysis. Methods and apparatus of detecting fax tones on a monitored phone line are well known and will, thus, not be discussed in further detail herein.  
      For the purpose of blocking faxes from known fax-marketers to subscribers of the fax blocking service, the example fax-blocker  195  of  FIG. 3  is provided with a fax-marketer detector  300  and a fax-blocker database  305 . The fax-blocker database  305  identifies the phone numbers of subscribers to the fax-blocking service and the phone numbers of known fax-marketers. Thus, when the fax-marketer detector  300  receives notification from the IP/SN  130  that a call is being placed, and this call is identified as a fax call, the fax-marketer detector  300  first addresses the fax-blocker database  305  to determine whether the called party is a subscriber to the fax-blocking service. If not, the fax-blocker  195  will not block the call. One of ordinary skill in the art will appreciate that in lieu of, or in addition to a fax-blocker database  305 , an SCP may be employed to store subscriber numbers and known fax-marketers.  
      If, however, the called party is a subscriber, the fax-marketer detector  300  again accesses the fax-blocker database  305  to determine if the calling party is a known fax-marketer. If the called party is a subscriber and the call is originating from a fax-marketer identified in the fax-blocker database  305 , the fax call will be blocked (unless expressly permitted through a subscriber override as explained below).  
      If, on the other hand, the fax-marketer detector  300  determines that the fax call is originating from a party that is not identified in the fax-blocker database  305 , the call will be analyzed to detect war-dialing techniques irrespective of whether or not the called party is a subscriber. This default analysis allows the fax-blocker database  305  to continuously improve and update for the benefit of subscribers. Newly identified calling numbers exhibiting war-dialing techniques are added to the database  305  so their fax calls will be blocked for subscribers, but passed-through to non-subscribers.  
      Thus, if a fax call is not blocked because the calling party is not identified in the fax-blocker database  305  as a fax-marketer, the fax-blocker  195  will use the information associated with the call to attempt to determine whether the calling party should be classified as a fax-marketer. Only fax calls are used for this determination. Thus, the fax-tone detector  310  screens the call to determine if it is a fax and/or the IP/SN  130  only invokes the fax-blocker  195  when it detects a fax call. If the call is not a fax, the fax-blocker  195  ignores the call (or the fax-blocker  195  is never notified of the call if the IP/SN  130  performs the screening operation). If the call is a fax from a caller not already identified as a fax-marketer, the fax-detector  300  activates a pattern-trap  320 . Similarly, improving the robustness of the fax-blocker database  305  without regard to subscriber status may proceed in alternate methods. For example, a bank of “decoy” fax machines may be employed to “trap” fax-dialers that are searching for fax machines, as will be discussed in further detail below.  
      The pattern-trap  320  generates records reflecting fax calls from each originating number that is not already identified in the fax-blocker database  305  as a fax-marketer. Prior to characterizing a fax caller as a fax-marketer, assuming that war dialing techniques, such as those illustrated in  FIG. 2 ( a ), are not immediately detected, the dates, times, and duration of each fax call from the fax caller are recorded in a record  400 , such as the record shown in  FIG. 4  in an attempt to detect war-dialing techniques similar to those illustrated in  FIG. 2 ( b ). These records are stored in a database such as the fax-blocker database  305 . As will be discussed later, records may be referred-to by the fax-blocker  195  to determine whether fax callers exceed various calling thresholds (which may or may not be subscriber defined). As fax callers make additional calls to a subscriber, row entries  405  are appended to the record  400  to reflect the fax call frequency (e.g., number of calls per unit of time) of the caller and the duration of the fax calls from that fax caller. Briefly returning to  FIG. 2 ( b ), upon an originating fax call at time “t 1 ” by line  1  ( 232 ), a record  400  may be created with a data row indicating when the fax was attempted, and a fax duration. Subsequently, at time “t 2 ” an additional row may be appended to the record  400  when line  1  ( 232 ) makes another fax transmission to destination fax 555-1112 ( 244 ).  
      The pattern-trap  320  of the illustrated example analyzes fax records  400  associated with an originating number in order to determine if the calling behavior reflects that of a fax-marketer. This analysis may be performed as the call is being made (“on the fly”). Additionally, or alternatively, the pattern-trap  320  may periodically analyze the fax records  400  to determine if the recorded calling behavior shown in the records reflects that of a fax-marketer. When the pattern-trap  320  detects a fax-marketer pattern, it saves the originating number(s) to the fax-blocking database  305 . Calls by originating numbers already identified as a fax-marketer in the fax-blocker database  305  do not need to be recorded or analyzed to conserve fax-blocker  195  storage and processing resources. The fax records  400  may also track whether detected patterns indicative of war dialing occur within, for example, a corporation or originate outside the corporation. For example, a corporation may wish to distribute an important memo, but not know destination numbers for all the fax machines within the company. The company may then employ dialing techniques indicative of war-dialing. As such, an “allow list” may include originating numbers that are authorized to employ dialing techniques indicative of war-dialing. The originating fax caller may then, for example, fax a corporate bulletin to every fax machine within the corporation.  
      A fax-marketer may attempt to elude pattern detection by dialing non-sequential destination numbers. For instance, the fax-marketer may dial numbers separated by 2 digits, or by any other integer. Alternatively, the fax-marketer may re-arrange the sequence of war-dialing numbers in any other pattern. The pattern-trap  320  may be adapted to detect any known dialing patterns.  
      Destination numbers that are not allocated to a client typically greet a calling party with a recorded message indicating that the number called is no longer in service. As such, the fax-blocker  195  may also employ a bank of “decoy” fax-capable devices in an effort to further populate the fax-blocking database  305 . The bank of decoy fax-capable devices may include disparate numbers of a telephone network that have never been assigned to a homeowner/business and/or disparate numbers that were previously used, but are no longer in service. Additionally, or alternatively, the bank of decoy fax-capable devices may include one or more groups of numerically consecutive numbers.  
      Fax-marketers that transmit to the decoy fax devices are unaware of whether or not the destination number reaches a homeowner or business. As such, the use of the decoy devices allows the fax-blocking database  305  to grow with originating numbers of fax-marketers, thereby improving the prevention of nuisance faxes for subscribers of the fax-blocker  195  services. Furthermore, the decoy devices may be configured to transmit at a low baud rate in an effort to consume the fax-marketer&#39;s resources for as long as possible. Because the fax-marketer cannot distinguish between the decoy fax-capable device and a fax machine at a home or business, such low baud rate settings result in slowing-down the rate at which fax-marketers may discover new fax destination numbers.  
      In order to permit subscribers to receive faxes from fax-marketer numbers stored in the database  305 , the fax-blocker  195  is provided a customer blocking service interface  330 . The customer blocking service may include a user-interface, including, but not limited to, a web-based interface that, upon identification of the subscriber&#39;s authentication credentials, permits that user to create, delete, and modify customized settings. Similar creation, deletion, and modification of the settings may also occur through an automated telephone interface. The subscriber may choose to accept a default blocking status (preferably initiated upon the setting up of the fax-blocking service) in which all numbers within the fax-blocker database  305  are blocked by the fax-blocker  195 . Alternatively, the subscriber may create a personalized list or a set of rules that may allow certain numbers from the fax-blocker database  305  to complete fax transmissions to the subscriber that created the rule (but to no others). For example, if a small or large business routinely sends inter-departmental memos via fax, then the pattern-trap  320  may identify this behavior as a potential fax-marketer and add the originating fax number to the fax-blocker database  305 . Although the originating number is, in fact, dialing numerically consecutive fax numbers simultaneously, the subscriber deems such activity useful rather than a nuisance. Thus, the subscriber can establish a rule permitting the “fax-marketer” in question to fax to any and all destination numbers associated with the subscriber.  
      Alternate example implementations of the fax-blocker  195  may employ the fax-marketer detector  300  to automatically identify that both the originating fax calling number and the numerically consecutive destination fax numbers are owned or operated by the same entity (e.g., business) and, thus, avoid the necessity of adding such originating fax calling numbers to the fax-blocker database  305 . Additional subscriber defined rules may include, but are not limited to, allowing a predetermined threshold of fax attempts per unit of time. For example, a subscriber may enjoy receiving some promotional sales information from a fax-marketer. If, however, the fax-marketer sends too many faxes, then the fax-marketer detector  300  may be programmed to block all subsequent fax transmissions for a period of time (e.g., to block all but a predetermined number of faxes per day).  
      The subscriber may also configure the fax-blocker  195  to transmit a personalized fax-back message to fax-marketers. The customer blocking service interface  330  may further allow the subscriber to create a personalized message in an attempt to dissuade the fax-marketers from sending additional faxes. Thereafter, upon the fax-blocker  195  identifying a new fax-marketer, the customer blocking service interface  330  may forward the subscriber&#39;s fax-back message to a fax-back module  350  along with the fax-marketer phone number stored in the fax-blocker database  305 . The fax-back module  350  may secure a telephone line, place a fax call to the fax-marketer, and transmit the fax-back message to that fax-marketer.  
      Although the above example enables user personalization of the fax-back message, persons of ordinary skill in the art will appreciate that non-personalized messages could also be appropriate. Further, although not discussed above, the subscriber would likely be expected to pay a monthly subscription fee for the fax-blocking service and an additional fee for the fax-back message service.  
      In addition to, or in lieu of the example fax-back message, the subscriber may configure the fax-blocker  195  with an announcement service to play an announcement to the originating caller. For example, after the originating caller&#39;s fax transmission attempt is blocked, the caller may manually call the destination number to determine if the destination fax number is working (e.g., to listen for fax-tones). Such a caller would be presented with a canned or personalized announcement, such as “Your call is blocked by the Fax Blocker. Please contact the party you wish to fax.” 
      Subscribers may add any numbers to their personalized list of faxes to block, even numbers that may not be present in the fax-blocker database  305 . Creation and modification of the subscriber&#39;s personalized list may also occur via the customer blocking service interface  330  in the aforementioned web interface. Such a web interface may include data entry fields for one or more telephone numbers, fax numbers, and a personalized list display screen. Additionally, the web interface may include various function commands to add new numbers, edit existing numbers, and delete numbers from the personalized list. Despite subscriber flexibility in customizing the personalized list to augment the fax-blocker database  305 , use of such a feature is optional and the example fax-blocker  195  preferably continuously and automatically updates the fax-blocker database  305  with new fax-marketer numbers without subscriber intervention.  
      A flowchart representative of example machine readable instructions for implementing the fax blocker  195  of  FIGS. 1 and 3  is shown in FIGS.  5 ( a ) and  5 ( b ). In this example, the machine readable instructions comprise a program for execution by: (a) a processor such as the processor  610  shown in the example computer  600  discussed below in connection with  FIG. 6 , (b) a controller, and/or (c) any other suitable processing device. The program may be embodied in software stored on a tangible medium such as, for example, a flash memory, a CD-ROM, a floppy disk, a hard drive, a digital versatile disk (DVD), or a memory associated with the processor  610 , but persons of ordinary skill in the art will readily appreciate that the entire program and/or parts thereof could alternatively be executed by a device other than the processor  610  and/or embodied in firmware or dedicated hardware in a well known manner (e.g., it may be implemented by an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable logic device (FPLD), discrete logic, etc.). For example, any or all of the fax-blocker  195 , the fax-marketer detector  300 , the fax-tone detector  310 , the pattern-trap  320 , the fax-blocker database  305 , the customer blocking service interface  330 , and/or the fax-back module  350  could be implemented by software, hardware, and/or firmware. Also, some or all of the machine readable instructions represented by the flowchart of FIGS.  5 ( a ) and  5 ( b ) may be implemented manually. Further, although the example program is described with reference to the flowchart illustrated in FIGS.  5 ( a ) and  5 ( b ), persons of ordinary skill in the art will readily appreciate that many other methods of implementing the example machine readable instructions may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, substituted, eliminated, or combined.  
      The program of  FIG. 5 ( a ) begins at block  500  where the fax-blocker  195  monitors the network  100  for calls by, for example, awaiting a message from the IP/SN  130 . If no calls are received at block  500 , the program loops at predetermined intervals until a call is received. When a call is received at block  500 , the fax-marketer detector  300  receives a message from the IP/SN  130  identifying the originating number and the called number. The fax-tone detector  310  then determines if the originating call is a facsimile at block  505 . If not a fax call (block  505 ), the fax-blocker  300  ignores the received call and returns a message to the IP/SN  130  to complete the call as normal. Control then returns to block  500 , where the fax-marketer detector  300  continues to monitor for fax calls. As described earlier, the IP/SN  130  may, alternatively, monitor originating calls for fax tones and invoke the fax-blocker  195  only when necessary. In such an approach, block  505  may be eliminated.  
      If the fax-tone detector  310  determines that the originating number is a fax transmission (block  505 ), the fax-marketer detector  300  verifies if the number being called (destination number) is a subscriber of the fax blocking service (block  510 ). If not, the fax-marketer detector  300  still compares the originating number against entries in the fax-blocker database  305  (block  515 ). If the originating number has a match in the fax-blocker database  305 , no further analysis is required and the fax-marketer detector  300 , thus, returns a message to the IP/SN  130  to complete the fax call. Control then returns to block  500  to monitor for additional calls. On the other hand, if the originating number is not a known fax-marketer (block  515 ), control advances to block  525 . Block  525  is discussed further below.  
      Returning, for purposes of discussion, to block  510 , if the called party is a subscriber, the fax-marketer detector  300  compares the originating number against entries in the fax-blocker database  305  (block  520 ). Similar to block  515 , if there is no match for the originating number in the fax-blocker database  305 , control advances to block  525 , discussed later. Alternatively, if there is a match for the originating number in the fax-blocker database  305 , that number may not have been categorized as a fax-marketer because, for example, various calling thresholds have not been exceeded, as will be discussed in further detail below. Thus, if the number is either not in the fax-blocker database  305 , or is in the database but not categorized as a fax-marketer, the fax-marketer detector  300  creates a record  400  of the calling number at block  525 , or updates an existing record  400  of the calling number. As discussed earlier in light of the war-dialing techniques of  FIG. 2 ( b ), an update of an existing record  400  may include entry of another line item  405 , as shown in  FIG. 4 . After the record  400  is updated or a new record  400  is created (block  525 ), control advances to block  550  where the fax-marketer detector routine is called. An example fax-marketer detector routine is discussed below in connection with  FIG. 5 ( b ).  
      Returning to block  520 , if the originating number is a known fax-marketer, the fax-marketer detector  300  reviews the personalized list of the called subscriber at block  530  to determine if the fax transmission should be blocked or permitted (block  530 ). As discussed earlier, the subscriber&#39;s personalized list may be created and edited via the customer blocking service interface  330 . Fax caller numbers not contained in the fax-blocker database  305  may be added by the subscriber for blocking. Conversely, numbers that exist in the database  305  may employ subscriber override rules to permit transmission of faxes from particular fax callers. The fax-marketer detector  300  reviews such subscriber personalized lists (e.g., the “allow list”) to either block additional fax caller numbers not contained within the database  305 , or allow fax transmissions for fax caller numbers listed in the database  305  (block  530 ). If the call is to be blocked (block  530 ), control advances to block  535  where a message to block the fax call is returned to the IP/SN  130 . One of ordinary skill in the art will appreciate that the message may be returned to an SCP and/or a feature/media server. If the call is to be permitted (block  530 ), control returns to block  500  to await the next call.  
      When a call is blocked (block  535 ), control advances to block  540 . As discussed above, the subscriber may automatically employ the fax-back service and/or the announcement service by using the fax-back module  350  after blocking the fax transmission. When so employed, a standard or personalized fax-back message (created by the subscriber with the customer blocking service interface  330 ) is sent to the fax-back module  350  along with the number of the fax marketer (block  540 ). The fax-back module  350  then secures a line and transmits the subscriber&#39;s fax message indicating, for example, that future calls are not welcome and will be blocked immediately (block  545 ). Control then returns to block  500  to monitor for additional fax calls. If the fax-back service is not employed (block  540 ), control returns to block  500  without passing through block  545 .  
      An example fax-marketer detection routine, which may be called at block  550 , is shown in  FIG. 5 ( b ). In the example of  FIG. 5 ( b ) the pattern-trap  320  analyzes the incoming call, or series of calls, to determine if a war-dialing technique is immediately evident (block  555 ). As discussed in connection with  FIG. 2 ( a ), the pattern-trap  320  may identify a series of numerically consecutive destination numbers being called substantially simultaneously by one or more originating numbers potentially affiliated with the same entity as fax dialing behavior indicative of a fax-marketer. When such behaviors are identified by the pattern-trap  320  (block  555 ), the fax-marketer detector  300  updates the fax-blocker database  305  to identify the caller(s) as fax-marketer(s).  
      The pattern-trap  320  may be structured to detect a variety of war dialing techniques. As fax-marketers develop new war dialing techniques, the pattern-trap  320  may be updated to detect those techniques. This is particularly easy when the pattern-trap  320  is implemented by software.  
      If the originating caller is not exhibiting calling conduct immediately indicative of war-dialing (block  555 ), such as conduct illustrated in  FIG. 2 ( a ), the pattern-trap  320  may determine whether the originating caller&#39;s conduct is indicative of fax-marketing by retrieving (block  560 ) and evaluating the record(s)  400  associated with the originating number(s) in question (block  565 ). As discussed in connection with  FIG. 2 ( b ), if fax calling patterns are detected over a predetermined period of time, such as numerically consecutive fax calls dialed sequentially by one or more originating lines, control advances to block  580  and the originating line(s) originating the fax call is identified as a fax-marketer. Other patterns detected by the pattern-trap  320  may include, but are not limited to, detection of integer skipping (e.g., 555-1111, 555-1113, 555-1115, etc.), alternating sub-patterns (e.g., 555-1111, 555-1121, 555-1131, 555-1112, 555-1122, 555-1132, etc.), and fibonacci-type patterns (e.g., starting with a ‘seed’ number 555-1101, 555-1101, 555-1102, 555-1103, 555-1105, 555-1108, 555-1113, 555-1121, etc.).  
      Fax calling patterns may also be identified by the pattern-trap  320  in view of various thresholds, also shown in  FIG. 2 ( b ). In particular, originating numbers dialing beyond a first threshold (block  570 ), such as the “suspected threshold”  262  of  FIG. 2 ( b ), are allowed to complete the fax call at block  595 , as long as the originating number(s) do not exceed a second threshold (block  575 ). However, originating numbers exceeding both the first and the second thresholds, such as the “confirmed threshold”  264  of  FIG. 2 ( b ) (block  575 ), are identified as fax-marketers (block  580 ).  
      Persons of ordinary skill in the art will appreciate that the first threshold (block  570 ) and the second threshold (block  575 ) may include a variety of other parameters. Predetermined thresholds may include, for example, a parameter counting the number of times a fax transmission is received, a parameter recording the dates and/or times that a fax transmission is received, a number of faxes to consecutive destination numbers, and/or a parameter reflecting the duration of each fax transmission received. The subscriber may set limits for each of these parameters (i.e., thresholds) in the customer blocking service interface  330 . As an example, the subscriber may set a threshold of three fax transmissions within a duration spanning one week. Fax transmissions attempting to make a fourth call within the time period of one week will subsequently be identified as a fax-marketer at block  580 .  
      Because the fax-marketer detector  300  always updates the record  400  of an originating caller at block  525 , even if a fax-marketer eludes immediate detection of a war-dialing technique, the subsequent analysis of an originating calling pattern over a longer period of time, and/or monitoring for various threshold violations, preferably enables the fax-blocker  195  to eventually identify such fax-marketers. If fax-marketers are identified in such a manner, the fax-marketer detector  300  further determines whether the called party is a subscriber (block  585 ) and, if so, sends a message to the IP/SN  130  to block the call (block  590 ). On the other hand, if the called party is not a subscriber (block  585 ), a message is sent to the IP/SN  130  to complete the call (block  595 ). In either event, control returns to block  550  of  FIG. 5 ( a ). Thereafter, the fax-blocker  195  continues to monitor for additional calls (block  500 ).  
      Although for simplicity, the flowcharts of FIGS.  5 ( a )- 5 ( b ) have been described as a single program executed in a sequential fashion, persons of ordinary skill in the art will appreciate that multiple instances of one or more components of the program represented by FIGS.  5 ( a )- 5 ( b ) may be simultaneously executed to handle multiple calls in parallel. For example, a new instance (e.g., a thread) of the software may be spawned whenever a call is received (block  500 ) and the corresponding instance (e.g., thread) may be collapsed whenever control is returned to block  500 .  
      Returning to  FIG. 1 , if the fax-blocker  195  is not currently operational, or if the fax-blocker  195  is operating on detecting fax-marketers not associated with a subscriber currently receiving a fax call, the subscriber will still realize benefits from prior fax-marketer detection efforts. The fax-marketer, using a fax-capable device, gains access to any telecommunications network through the SSP  120 . The SSP  120 , routes the call through the network and recognizes intelligent network calls and routes them pursuant to directions from the SCP  120 . The STP  150  is a packet switch that shuttles messages between the SSP  120  and the SCP  140 . The SCP  140  is referenced in view of the originating fax call for instructions on how to proceed. Because the SCP  140  contains data from the fax-blocker database  305 , prior determinations of fax-marketers and their corresponding originating numbers are compared against the originating fax caller. The SCP  140  returns a block instruction if the originating fax caller number matches a fax-marketer number previously determined. Alternatively, if the originating fax number does not match a previously determined fax marketer, the SCP  140  returns an allow instruction, thereby permitting a destination fax-capable device to receive the fax. The SCP  140  may also interact with the IP/SN  130  to detect fax tones to determine if the call is a fax.  
      Because the SCP  140  has access to, or a copy of the fax-blocker database  305 , the SCP  140  compares the originating number of the fax-capable device against the fax-blocker database  305 . If the SCP  140  determines a match, the subscriber&#39;s personalized list is checked by the SCP  140  for specific fax numbers that the subscriber prefers to allow. If the personalized list does not include the originating number of the fax-capable device, then the call is blocked. On the other hand, if the personalized list includes the originating number of the fax-capable device, then the call is allowed. Similarly, if the SCP  140  finds no match in the fax-blocker database  305  in view of the originating number of the fax-capable device, then the call is allowed to proceed to the destination fax-capable device.  
       FIG. 6  is a block diagram of an example computer  600  capable of implementing the apparatus and methods disclosed herein. The computer  600  can be, for example, a server, a personal computer, an IP/SN, an SCP, an STP, or any other type of computing device.  
      The system  600  of the instant example includes a processor  610  such as a general purpose programmable processor. The processor  610  includes a local memory  611 , and executes coded instructions  613  present in the local memory  611  and/or in another memory device. The processor  610  may execute, among other things, the example machine readable instructions illustrated in FIGS.  5 ( a ) and  5 ( b ). The processor  610  may be any type of processing unit, such as a microprocessor from the Intel® Centrino® family of microprocessors, the Intel® Pentium® family of microprocessors, the Intel® Itanium® family of microprocessors, and/or the Intel XScale® family of processors. Of course, other processors from other families are also appropriate.  
      The processor  610  is in communication with a main memory including a volatile memory  612  and a non-volatile memory  614  via a bus  616 . The volatile memory  612  may be implemented by Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRAM) and/or any other type of random access memory device. The non-volatile memory  614  may be implemented by flash memory and/or any other desired type of memory device. Access to the main memory  612 ,  614  is typically controlled by a memory controller (not shown) in a conventional manner.  
      The computer  600  also includes a conventional interface circuit  618 . The interface circuit  618  may be implemented by any type of well known interface standard, such as an Ethernet interface, a universal serial bus (USB), and/or a third generation input/output (3GIO) interface.  
      One or more input devices  620  are connected to the interface circuit  618 . The input device(s)  620  permit a user to enter data and commands into the processor  610 . The input device(s) can be implemented by, for example, a keyboard, a mouse, a touchscreen, a track-pad, a trackball, isopoint and/or a voice recognition system.  
      One or more output devices  622  are also connected to the interface circuit  618 . The output devices  622  can be implemented, for example, by display devices (e.g., a liquid crystal display, a cathode ray tube display (CRT), a printer and/or speakers). The interface circuit  618 , thus, typically includes a graphics driver card.  
      The interface circuit  618  also includes a communication device such as a modem or network interface card to facilitate exchange of data with external computers via a network (e.g., an Ethernet connection, a digital subscriber line (DSL), a telephone line, coaxial cable, a cellular telephone system, etc.).  
      The computer  600  also includes one or more mass storage devices  626  for storing software and data. Examples of such mass storage devices  626  include floppy disk drives, hard drive disks, compact disk drives and digital versatile disk (DVD) drives. The mass storage device  626  may implement the fax-blocker database  305 .  
      Although certain example methods, apparatus, and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.