Abstract: When a Java application AP originates a call to a certain communication node, a Java application manager JAM refers to the history of outgoing/incoming calls and telephone directory data mentioned above to determine whether the call origination processing should be granted by checking whether the telephone number of the communication node, for which call origination is to be implemented, is included in the history of outgoing/incoming calls or the telephone directory data. The determination is based on an idea in which, if the telephone number of the communication node for which call origination is to be performed is included in the history of outgoing/incoming calls or the telephone directory data, then the call origination processing is valid on a basis of the recognition in that a portable telephone has performed communication with the communication node in the past or the user has recognized it as a communication partner.

Abstract: A predictive model system is used to detect telecommunications fraud. Call records (CDRs) provided by telephone companies are evaluated against specified rules. If one or more rules are matched, the system generates an alert. Pending alerts for a customer form a case, describing the caller's calling patterns. A predictive model determines a score that is predictive of the likelihood that the call involved fraud. Cases are queued for examination by analysts.

Abstract: A method and an apparatus for protecting call privacy allow a calling party to control the privacy of a telephone call by selecting among a group of privacy options that represent varying degrees of privacy and enforcing the selected privacy options during the call. The privacy options selected for the call limit the ability of a called party to manipulate the call. For example, the privacy options may prevent the called party from forwarding the call, transferring the call, conferencing the call, and/or listening to the call via a hands-free speakerphone. In an additional aspect of the invention, the selected privacy options are transferred to any voicemail messages that are generated as a result of the call made by the calling party. The preferred call privacy system is implemented in a packet-based network that carries voice and data.

Abstract: A system and method of telephony security for controlling and logging access between an enterprise's end-user stations and their respective circuits into the public switched telephone network (PSTN). A security policy, i.e., a set of security rules, are defined for each of the extensions, the rules specifying actions to be taken based upon at least one attribute of the call on the extension. Calls are detected and sensed on the extensions to determine attributes associated with each call. Actions are then performed on selected calls based upon their attributes in accordance with the security rules defined for those extensions.

Abstract: A communication support system includes a command signal recognition unit which discretely detects a command signal sent by a telephone unit and a command signal sent from a telephone network, and determines whether the command signal is from the telephone unit, the command signal from the telephone unit indicating one of a plurality of telephone services of a data processing device. A signal transmission inhibition unit inhibits transmission of a signal from the telephone unit to the telephone network. A telephone service processing unit performs a telephone service processing of the data processing device for the telephone service indicated by the command signal from the telephone unit, the telephone service processing unit starting execution of the telephone service processing when the command signal recognition unit determines that the command signals is from the telephone unit.

Abstract: A method and device for suppressing threshold alerts in a telecommunication fraud control system is disclosed. Threshold alerts are generated when the count of a certain category of call exceeds a certain threshold. These counts are maintained in relation to particular accounts. A fraud analyst determines whether or not a particular account will have alert suppression enabled, based on the type of account and its history. Once alert suppression is enabled, the count is multiplied by a coefficient before determining whether to issue a threshold alert. If the multiplied count still exceeds the threshold, an alert is generated. If not, no alert is generated.

Abstract: A method and apparatus for managing institutional telephone activity utilizes a computer control unit to control a trunk management unit, which connects institutional telephones to outside telephone lines. The computer control unit contains a database for storing the calling privileges and restrictions of institutional users and for recording calling transactions made by the users. The computer control unit implements a prospective call screening feature whereby outside recipients of undesired calls from the institution may enter a code that directs the computer control unit to prohibit similar calls in the future.

Abstract: A telecommunications system, service control point and method are described that can pre-screen a telephone call to help prevent telephone toll fraud. More specifically, the telecommunications system includes a service control point capable of receiving information about a telephone call originated by a calling party, and further capable of determining whether the telephone call has a fraudulent attribute. If the telephone call has a fraudulent attribute, then the calling party is informed that there is a possibility of telephone toll fraud occurring if the telephone call is connected to a called party. And, if the telephone call does not have a fraudulent attribute, then the telephone call is automatically connected to the called party.

Abstract: A communication support system includes a command signal recognition unit which discretely detects a command signal sent by a telephone unit and a command signal sent from a telephone network, and determines whether the command signal is from the telephone unit, the command signal from the telephone unit indicating one of a plurality of telephone services of a data processing device. A signal transmission inhibition unit inhibits transmission of a signal from the telephone unit to the telephone network. A telephone service processing unit performs a telephone service processing of the data processing device for the telephone service indicated by the command signal from the telephone unit, the telephone service processing unit starting execution of the telephone service processing when the command signal recognition unit determines that the command signal is from the telephone unit.

Abstract: A system and device for blocking fraudulent special service calls in a long distance telephone system is disclosed. The Automatic Number Identifiers (ANIs) of originating numbers within Local Exchange Carriers (LECs) are blocked from calling certain special service call numbers by including the ANI in the special service call number record in the long distance carrier's Service Management System (SMS) database. ANIs to be blocked are selected by fraud control based on certain network traffic flow thresholds. When the switching elements in the long distance carrier retrieve an SMS record for a particular special service call, it is determined whether the origin of the call corresponds to an ANI in the SMS record. If it does, the call is blocked.

Abstract: A method for inhibiting the use of dual tones over an established voice channel of a telecommunications network. The method inhibits a call tone by removing at least one frequency selected from a group of frequencies used for in-band signaling. The method may also determine a time for inhibiting the call tone.

Abstract: A method and system include screening and routing telephone calls, generating calling data reports and discounting billing for a customer's wide area centrex/PBX network, which includes an abbreviated dialing plan. A service control point (SCP) determines whether to block an outgoing call based on stored blocking tables and a privilege class of the calling station. The SCP determines whether to route the call through a private trunk group from a host switch to a private facility, and through an alternative trunk group when the private trunk group is unavailable. The SCP determines whether the call is eligible for discounted billing and generates a billing record, which is modified by a service switching point to indicate the discount. The SCP also samples calling data from service switching points and transmits the sampled data to a front end processor for formatting into station message detail recording (SMDR) data.

Abstract: Call forwarding can be used to commit fraud or to evade security controls in inmate calling systems. Information from the Common Channel Signaling (CCS) network can be used to detect when a dialed number has been call forwarded and furthermore prevent the call forwarding event from occurring. It is possible to determine whether a dialed number has been call forwarded by setting up a call to that number with the Redirection Counter in the Initial Address Message set to the maximum value allowed in the signaling system being utilized (e.g., CCS7). If the terminating switch fails to set up the call even though the trunk is available, the assumption is made that the call is call forwarded. A second attempt is then made to set up the call a second time setting the Redirection Counter in the Initial Address Message to zero. If the terminating switch returns an Answer Complete Message indicating that the call has been successfully set up, then it has been demonstrated that the dialed number is call forwarded.

Abstract: A user programmable telephone call screening device which screens incoming telephone calls by comparing a caller's identifying code to user programed codes and either diverting the call, without ringing the phone, to an answering device or ringing the phone for pickup by the intended recipient. The screening device is automatically deactivated to permit all incoming calls to ring through after an out going 911 or other user defined emergency call is made. The screening device also functions to permit the user to look up and automatically dial a call to phone numbers entered into the screening device's memory by the user. The screening device's programmable CPU and memory permit many functions to be incorporated into the device including, in-coming and out-going call blocking by area code, phone number and time of day, call forwarding, pager notification and recording out-going call information to permit the user to verify calls against telephone company billing records or for other purposes.

Abstract: The invention relates to a procedure and system for executing a personal alarm function by means of a telecommunication terminal in a telecommunication system comprising a telephone network, a telephone exchange connected to the telephone network, an intelligent network element connected to the telephone network and a telecommunication terminal connected to the telephone network. In the procedure of the invention, a hidden mode is defined in conjunction with a call made from the telecommunication terminal, the mode is verified in the intelligent network element in conjunction with the setup of each call and an alarm function is executed when the mode differs from the defined mode. The system of the invention comprises means for defining a hidden mode in conjunction with a call made from the telecommunication terminal, means in the intelligent network element for verifying the mode in conjunction with the setup of each call and means for executing an alarm function when the mode differs from the defined mode.

Abstract: A telephone having call-screening capabilities includes a memory for storing call-screening data. The call-screening data is used by the telephone to screen incoming calls. Incoming calls can be accepted, rejected, or diverted based on the call-screening data stored in memory. The call-screening data is automatically updated when a call is made to a previously screened number provided that certain predetermined conditions are satisfied, so that calls can be received from the previously screened number. Updates may be made, for example, when the call to the previously screened number is unanswered, when it is diverted to a recording device, or when the call is made to a number from which a previously screened call was made. The phone can be programmed so that updates automatically expire after a predetermined time period has elapsed.

Abstract: A computer implemented method is disclosed for automatically intercepting and analyzing computer modem commands for toll characteristics andthen alternatively permitting or preventing the computer modem command based on the results of the toll analysis and user preferences. The computer modem command is analyzed by extracting any proposed telephone dialing instructions and comparing the proposed telephone number to be dialed with data provided by the local telephone service provider (TSP) in order to determine whether the proposed telephone number would result in a “toll call,” or telephone service charges over and above the usual monthly rate, if transmitted to the modem. If a telephone service charge would result, the computer user is notified and prompted to give further instructions concerning whether the toll call should be placed.

Abstract: A system and method for adding non-embedded network interface drivers to a communication switch with minimum impact on the switch. A proxy driver which presents the appearance of a network interface driver is embedded in the switch. An external hardware platform containing the non-embedded driver is connected to the proxy driver. The external hardware platform includes a proxy interface connected to the proxy driver. The proxy driver sends signals derived from the switch's internal interface to the proxy interface, which in turn replicates the switch's internal interface in the external hardware platform for controlling the non-embedded driver.

Abstract: A method and apparatus for managing institutional telephone activity utilizes a computer control unit to control a trunk management unit, which connects institutional telephones to outside telephone lines. The computer control unit contains a database for storing the calling privileges and restrictions of institutional users and for recording calling transactions made by the users. The computer control unit implements a prospective call screening feature whereby outside recipients of undesired calls from the institution may enter a code that directs the computer control unit to prohibit similar calls in the future.

Abstract: An image capture, conversion, compression, storage and transmission system provides a data signal representing the image in a format and protocol capable of being transmitted over any of a plurality of readily available transmission systems and received by readily available, standard equipment receiving stations. The system is adapted to be installed in a standard cellular phone configuration, providing a portable, hand held, wireless transmission system for transmitting video image signals to a remote receiving station.

Abstract: An improved workstation for use in a telecommunications fraud detection system is disclosed. The workstation provides a fraud analyst with streamlined access to case records defining one or more subcases or fraud analyses associated with specified calling card numbers. Additionally, the workstation is preferably interconnected to a customer information database and may display a variety of detailed customer information on monitor together with associated case or subcase information. Through the use of assorted tools provided by the workstation, a fraud analyst may efficiently study instances of possible telecommunications fraud on a case-by-case basis.

Abstract: A method by which a line driven, microprocessor controlled special information tone (SIT) generator is coupled to a conventional home or business telephone for generating a set of audible tri-tone signals of the type usually generated by a local telephone exchange carrier when the telephone is not operating properly. The method of the present invention has particular application for preventing unsolicited telemarketing calls from reaching the telephone of an intended recipient. More particularly, the predictive dialer that usually initiates the telephone call from a telemarketer is fooled into mistakably interpreting the set of audible tri-tone signals from the tone generator to mean that the telephone of the intended recipient is not available to the telemarketer, whereby the telemarketer's call will be automatically terminated without the telemarketer being placed in direct communication with the intended recipient.

Abstract: The specification discloses a method for security control of network distant input using caller ID, which uses an ID decoder to decode and extract a caller ID from an incoming message and determine whether the caller ID exists in its database before starting a password checking step. The invention also discloses the corresponding device.

Abstract: A movable terminal and a coaxial connector have greatly improved durability and have outstanding contact/connection reliability, and are included in a communication apparatus. A coaxial connector includes a two-split synthetic resin case having a lower insulating case and an upper insulating case, a metal fixed terminal, a movable terminal, and an external terminal. The movable terminal having a spring movable function includes a movable contact portion with which the fixed terminal makes contact, a fixed portion fit in the upper and lower insulating cases, and a lead portion bent in an L-shape. The movable contact portion has a frame-shaped portion, a spring movable portion upwardly curved in an arcuate shape, and a contact portion provided at the approximate center of the spring movable portion.

Abstract: A central station blocks calls for a subscriber. The central station receives a call from a caller and provides an audio message to the caller requesting that the caller provides a first indicator if the caller is an unwanted caller or a second indicator otherwise. The central station receives the first indicator or the second indicator. If the central station receives the first indicator, the call is blocked. If the central station receives the second indicator, the call is passed through.

Abstract: An improved system for detecting and preventing telecommunications fraud prior to call connection, in which attempted calls are screened for fraud at the point of calling card validation in the SCP. The SCP accesses a database holding a variety of fraud decision nodes that may be interrelated and grouped together to cooperatively define fraud screening trees against which attempted calls may be tested. A fraud screening tree ultimately produces a fraud prediction based on a variety of information concerning the attempted call. The present invention therefore facilitates fraud screening with greater granularity and customization.

Abstract: A method and a system to meter and control the usage of a telephone. The metering and control functions are applicable for specific outgoing or incoming destination, the specific user of the telephone, the time of the day when an outgoing call is made or an incoming call is received, and the calling time allowed either collectively or per the specific outgoing or incoming destination. At least one list of a plurality of lists is stored. Each of the stored lists includes at least one entry, and each entry includes at least one of a plurality of fields. The fields within an entry contain information that is used by the metering circuitry to execute the control functions. The outgoing or incoming phone number is received and encoded using a codec unit and compared with all the entries stored within the lists. The result of the comparison is used to determine if a match exists between the encoded phone number and one of the entries stored within the lists.

Abstract: A configurable and scalable rules-based thresholding system, method and computer program product for processing event records includes a core infrastructure and a configurable domain-specific implementation. The core infrastructure is generically employed regardless of the actual type of network being monitored. The domain-specific implementation is provided with user specific data and rules. The core infrastructure includes an event record enhancer which enhances events with additional data and a threshold detector which determines whether an enhanced event record, alone or in light of prior event records, exceeds one or more thresholds. The enhancer can access external databases for additional information related to an event record. In one embodiment, the enhancer generates feature vectors to represent enhanced event records. The threshold detector receives enhanced event records from the event record enhancer.

Abstract: A method and apparatus for detection and prevention of calling card fraud is disclosed. The invention provides enhanced intelligence and efficiency in part applying by a fraud analysis associated with a calling card bill type or service provider as identified by originating partitions in network switches. Additionally, the invention incorporates a case-subcase arrangement of fraud analysis information and conducts fraud analysis on a case-by-case basis, thereby providing streamlined handling of suspected fraud. Still additionally, the invention includes an administrative monitor that continuously collects and reviews fraud system status information to detect abnormalities in the system.

Abstract: Access is granted to a portion of a computing system, such as to a configuration menu of a telephone system. In order to grant access, a password is received from a user. A variable password is also calculated. The variable password varies with time. For example, the variable password varies with a current date and with a time of day stored by the computing system. The password received from the user is compared with the calculated variable password. When the password received from the user is equal to the calculated variable password, access is granted.

Abstract: A method and system for generating a predetermined message during selected calls-in-progress utilizes a communication station to detect a connection being attempted between a subscriber telephony device and a second telephony device. An adjunct processor determines whether the connection between the subscriber telephony device and the second telephony device requires call-attendant monitoring and if so, monitors the connection between the subscriber telephony device and the second telephony device to identify a predetermined event. An intelligent peripheral unit generates the predetermined message based on the predetermined event and a subscriber profile associated with the subscriber telephony device.

Abstract: A method and a system for recording information about a call in which voice signals of a party initiating a call are recorded, an acceptance verification query call to a billed party of the call is generated, and voice signals that are an affirmative response to the acceptance verification query call by the billed party are recorded. The voice signals of the party initiating the call and the billed party are then digitized and stored in a memory. The call can be a collect call or a bill-to-third-party call. Additionally, information relating to the time, date, the originating telephone number and the terminating telephone number of the call are stored in the memory. When the billed party challenges the charges for the call, the recorded voice signals of the party initiating the call and the billed party are generated as information that can be used for sustaining the charges.

Abstract: A method and apparatus for detecting whether a remote party has added a secondary telephone destination to a telephone call, for example through the activation of three-way calling service, conference calling or two lining bridging, by identifying an echo characteristic to the telephone connection between the local and the remote telephone and monitoring the echo characteristic to determine whether there is a significant change. The addition of a secondary telephone destination can be verified by continuing to monitor the echo characteristic to determine whether it has returned to its original value.

Abstract: The personal communications controller (PCC) may be programmed with a customized service configuration based on which telecommunications functions in connection with multiple telephone terminals are managed. The PCC system is designed to provide enhanced service value to all of the telephone terminals throughout a residence coupled to a single telephone communication line entering the residence. The PCC may provide service differentiation on an individual basis to the telephone terminals and, furthermore, differentiated treatment may be effected on a per telephone call basis. The customized service configuration may be generated using a personal computer from which it is downloaded to the PCC.

Abstract: The personal communications controller (PCC) may be programmed with a customized service configuration based on which telecommunications functions in connection with multiple telephone terminals are managed. The PCC system is designed to provide enhanced service value to all of the telephone terminals throughout a residence coupled to a single telephone communication line entering the residence. The PCC may provide service differentiation on an individual basis to the telephone terminals and, furthermore, differentiated treatment may be effected on a per telephone call basis. The customized service configuration may be generated using a personal computer from which it is downloaded to the PCC.

Abstract: A system and process for automatic storage, enforcement and override of consumer do-not-call (DNC) requests includes a control device for selectively blocking communication between a communication device and a destination over a communication medium. The control device is connected to the communication medium and to a database for storing identifiers of destinations for which communication is to be blocked. The communication device has an input mechanism responsive to a user to generate an identifier of the destination. The input mechanism is also responsive to an update signal indicating that the identifier should be added to the database or an override signal indicating that the blocked call should in fact, be permitted, thereby overriding the blocking mechanism. The communication device is automatically updated with information stored in the database which may be used by the communication device to process further communication.

Abstract: A selective ring response device for a telecommunication line comprises: a ring tone detector circuit for detecting a special ring tone different from a standard ring tone, the ring tone detector circuit coupled to the communication line; an interface circuit capable of placing the communication line in an off-hook status and capable of selectively applying a switch hook flash signal to the communication line, the interface circuit coupled to the communication line; and a control circuit coupled to the ring tone detector circuit and the interface circuit, wherein the interface circuit places the communication line in the off-hook status, and at the user's request applies the flash hook signal to the communication line in response to the ring tone detector circuit detecting the special ring tone.

Abstract: A telephone apparatus for providing service to a plurality of telephones located at a particular facility, and with the capability of controlling the connection of calls to such telephones as well as recording selected phone conversations. In particular, control of call connection is accomplisued with access control data that is phone-related and PIN number-related. Phone-related data activates the telephone based on, for example, its location in the facility, time of day and day of the week. PIN number-related data allows access to the phone depending on data associated with the caller to whom a unique PIN number has been assigned. The recording of conversations is controllable based on a comparison of call-related data, particular to the call being attempted, with stored recording control data that may also be phone-related and/or PIN number-related.

Abstract: A method and apparatus for operating on intelligent network calls in a telephone exchange with multiple access subsystems and an interconnection subsystem is provided. A list of intelligent network criteria is stored in each access subsystem. When an incoming call is received the access subsystem determines whether the incoming call matches one of the intelligent network criteria stored in the access subsystem. If a match occurs the access subsystem performs an intelligent network function. Intelligent network function may include filtering the call. If filtering is to occur a filtering method associated with the matched active filtering criteria is applied to determine whether a call should be blocked as a function of the filtering method.

Abstract: The invention relates to a method for deciding on the acceptance or non-acceptance of a call by taking into consideration data signaled in conjunction with the attempt to establish a connection to a certain subscriber who is the called party, wherein in addition to the signaled data other data are considered which identify the actual situation of the certain subscriber and wherein the data are combined according to freely predetermined criteria, as well as a circuit module, a communication terminal, a portable unit, and a network component for a telecommunication network.

Abstract: An arrangement for inhibiting the completion on defrauding calls. Calls to certain area codes are sometimes not subject to the kinds of regulations characteristic of U.S. based area codes. The result is that callers are charged an exorbitant fee (frequently several dollars per minute) without realizing that they are incurring such charges. In accordance with applicant's invention, a data base maintains a record of suspected telephone numbers and calls to the suspected area codes are checked to see if the call is to one of the suspected numbers. If so, the caller is warned and can disconnect before the call is completed. Advantageously, possibly for the payment of the fee, callers are saved from making calls with exorbitant charges.

Abstract: A database tool comprises a computer-implemented method for extracting systematic information from one or more databases that apparently only comprise data noise or seemingly unrelated data items. Criminal and community relationships that exist amongst telephone and internet subscribers are extracted from large telephone databases derived from wire taps and/or long distance telephone records. A telephone records file is used that comprises a caller's telephone number, dialed telephone numbers, and the time. A second database comprises a list of telephone numbers which are suspicious for some reason, and a descriptor as to why each such telephone number is suspicious. A third database includes biographical data about the telephone subscribers, such as name, address, and other facts. The unique telephone numbers in the database are identified. Matches between the first and second databases are made. Related components are grouped into clusters. The valence for each telephone number is computed.

Abstract: A device (FIG. 1, item 110), which may be remotely controlled, inserted between a telephone (FIG. 1, item 100) and a telephone line (FIG. 1, item 120) that controls the telephone's ringer to silence it or not, to cause it to ring in a different manner to signal an event other than an incoming telephone call (FIG. 1, item 140), and/or to signal another device (FIG. 1, item 130) to indicate an incoming call.

Abstract: The invention relates to a communication system comprising a station (2) for charge metering of a connection point. This station comprises a monitoring circuit (7) for detecting a request for a connection set-up from the connection point (3), either for establishing the absence of a message after a given period of time, or for evaluating the contents of a message that has arrived from the connection point (3) after the request for a connection set-up has arrived, and for rejecting the request for a connection set-up if invalid parameters of the connection point (3) are established.

Abstract: A telephone station interface is provided with apparatus for detecting when a called party has or is attempting to patch or bridge one telephone call with another telephone call. The detecting of such bridging or conferencing is accomplished through the detection of tones which are commonly associated with such activities, such as a ring signal, a busy signal, special information tones (SIT tones), dual tone multi-frequency (DTMF) tones or so-called Touch Tones, call progress tones, or other tones that occur when calls are placed. The present invention does not have the capability of sensing clicks, pops, or other audio signals associated with the conferencing of multiple communications circuits. The method and apparatus herein are for managing institutional telephone activity, and utilize a computer control unit to control a trunk management unit, which connects institutional telephones to outside telephone lines.

Abstract: A method of and system for completing a telephone call from an originating number to a password protected destination number at a terminating switch. The system receives dialed digits from the originating number, and compares the dialed digits received to candidate dialing schemes. Whenever a sequence of dialed digits received satisfies a dialing scheme for a call to a destination number, the system waits to receive trailing dialed password digits. When the system has received the trailing digits, the system sets a destination number equal to the sequence of dialed digits received, and sets a password equal to the trailing digits received. The system then forwards a call request with the set destination number and the set password to the terminating switch for call processing. The terminating switch determines whether the destination number has a password associated with it, and if so, completes the call only when the set password matches the password associated with the destination number.

Abstract: A user-authentication system includes an authorized user device (AUD) for transmission of dtmf tones to a user-verification system (UVS) over a telephone network, where user-verification is performed and authorized users are granted access to a desired service. In a memory module of the AUD, a plurality of passphrases and identifying data are stored for subsequent transmission to the UVS. The UVS includes a memory module for receiving and storing the passphrases and identifying data, and a processor for determining whether user-stated passphrases correspond to the stored passphrases, and for prompting the user with knowledge-based questions and determining whether the identifying data corresponds to answers given by a user in response to the knowledge-based questions.

Abstract: A system and method for controlling the use of a telephone based on usersupplied access criteria. The system includes a database for storing the access criteria. The access criteria can be modified in response to commands received from the telephone. The system also includes a switch, electrically coupled between the telephone and a telephone network, for selectively coupling the telephone and the telephone network based on the access criteria stored in the database.

Abstract: A device and method for securing terminal equipment connected to a communications line is disclosed. The device, when inserted into the communications line between the caller and terminal equipment, places an air gap in the communications line physically preventing unauthorized callers from accessing the equipment. The device employs an authentication line separate from the communications path that is used to authenticate the caller wishing to use the terminal equipment. The caller must first call the authentication line where the information regarding the source of the caller is retrieved and stored. Once the caller's source is identified, the device answers the line and requires that the caller enter an authentication code. If a proper authentication code is entered, the device disconnects the authentication line and waits a predetermined amount of time for a call on the communications line.

Abstract: A method is provided for a telephone subscriber to distinguish between callers. The method is accomplished by storing a pass code for a subscriber's telephone within a memory of the telephone system. Callers who have been informed of the pass code and who call the subscriber's telephone and enter the pass code receive special treatment. For example, upon the caller calling the subscriber's telephone, a normal ringing pattern is applied to the subscriber's telephone while a ring back signal is returned to the caller. Upon the caller entering the pass code, a special ringing pattern is applied to the subscriber's telephone. The special ringing pattern is different than the normal ringing pattern and thus indicates to a subscriber of the subscriber's telephone, even before the telephone is answered, that the caller is one of a select group of callers to whom the subscriber has shared the pass code.