Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M15/00—Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
  • H04M15/70—Administration or customization aspects; Counter-checking correct charges
  • H04M15/73—Validating charges
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/66—Substation equipment, e.g. for use by subscribers with means for preventing unauthorised or fraudulent calling
  • H04M1/667—Preventing unauthorised calls from a telephone set
  • H04M1/67—Preventing unauthorised calls from a telephone set by electronic means
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M15/00—Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M15/00—Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
  • H04M15/47—Fraud detection or prevention means
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M15/00—Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
  • H04M15/48—Secure or trusted billing, e.g. trusted elements or encryption
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/38—Graded-service arrangements, i.e. some subscribers prevented from establishing certain connections
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M2215/00—Metering arrangements; Time controlling arrangements; Time indicating arrangements
  • H04M2215/01—Details of billing arrangements
  • H04M2215/0148—Fraud detection or prevention means
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M2215/00—Metering arrangements; Time controlling arrangements; Time indicating arrangements
  • H04M2215/01—Details of billing arrangements
  • H04M2215/0156—Secure and trusted billing, e.g. trusted elements, encryption, digital signature, codes or double check mechanisms to secure billing calculation and information
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M2215/00—Metering arrangements; Time controlling arrangements; Time indicating arrangements
  • H04M2215/70—Administration aspects, modify settings or limits or counter-check correct charges
  • H04M2215/7072—Validate charges

Definitions

• the present invention relates to telephony, more particularly a method and a device for combating the unauthorized use of a telephone line connecting a telephone exchange and an authorized telephone.
• authorized telephone is meant either a subscriber telephone intended for private use, or a prepaid public telephone.
• These devices are said to be prepayment because, prior to their use, it is necessary to introduce a means of payment.
• the means currently known are tokens, coins, as well as more recently value cards, in particular of the optical, magnetic or electronic chip type.
• Document PCT / DE95 / 00838 describes a countermeasure device using two modules, one on the side of the telephone and the other on the side of the exchange.
• the "telephone” module identifies itself with the "central” module and the latter authorizes the connection of said central. If an off-hook is detected by the "central” module and identification does not occur, then connection with the central is prohibited. This identification process between the two modules can be done for the duration of the conversation at regular intervals.
• This device has the advantage of simplicity with the disadvantage of defining a constant code for the user.
• the imagination of fraudsters has no limits and you should know that there are inexpensive devices on the market that connect directly to the line and display the codes issued on it. It is therefore easy to memorize the code then to reproduce it during the fraudulent use of the line.
• the document FR 2 765 061 describes a module placed in series on the line and comparing the activities upstream of the module (towards the telephone) and downstream of this module (towards the central office). If these activities are different, the circuit is interrupted and a signal is generated by this module. This signal can also be injected on the line to deter fraudsters.
• the upstream portion of the line is secure and that any telephone can be connected to it. This solution does not respond to the risk of fraud on the portion of the line upstream of said module.
• the presence of the switch in series on the line is necessary. This is often difficult to obtain on an existing installation and requires the duplication of detection equipment (upstream detector and downstream detector).
• the object of the present invention is to prohibit any unauthorized use of the telephone line without modification on the telephone side.
• a method according to the invention characterized in that it consists, in an initialization phase, in establishing and storing an electrical reference signature representative of all of the electrical parameters of the line when in use by the device authorized to telephone, in a monitoring phase, to measure the electrical parameters composing the electrical signature of the line in use by a telephone, to compare this signature with the stored reference signature and, in case the two signatures differ, to make the use of the line impossible
• electrical signature is meant a set of electrical parameters of the telephone representative of all the phases of operation, in particular line seizure, dialing, end of communication, reception of a call.
• this method is advantageously implemented by a monitoring module comprising measurement means for establishing the signature as well as for comparing it with the reference signature.
• This module also includes means to prohibit the use of the line if the two signatures differ. It can be placed anywhere on the line to be protected because the electrical parameters can be measured wherever the authorized telephone and therefore the fraudulent telephone are placed. However, it is desirable to have it as close as possible to the central office so that the fraudster cannot neutralize the protection by interrupting, even temporarily, the line downstream from the fraudulent telephone.
• the monitoring module can open the line as long as it is located upstream of the fraudster or inject a signal making any dialogue on the line impossible.
• the invention is not limited to a module in series on the telephone line but also extends to a module connected in parallel on the line. Indeed, it is often difficult, on an existing installation to insert a device in the line. On the other hand, it is always possible to connect in parallel on the bars for this purpose, this module at the entry of the line in a building for example. In this case, it is not possible to cut the line, and the detection of an intruder will be combated by the generation of a noise in order to dissuade it from being used.
• This noise can take various forms, for example the form of DTMF pulses, of fixed or variable frequencies, of white noise.
• the process according to the invention takes place in two stages.
• the first consists in acquiring the signature of the telephone to be protected.
• the parameters of the signature can be directly loaded into the module's memory.
• an initialization phase of the telephone's parameters is necessary.
• the module is placed in a learning mode in which it analyzes the electrical parameters of the telephone at the end of the line and constructs the electrical signature of the latter. This mode is initiated manually and can end manually or automatically after a certain time.
• the installer When installing a new telephone on a protected line, it is possible to control the initialization phase remotely.
• the installer has an initialization module which informs the monitoring module of the installation of this new telephone.
• the dialogue between these two modules is based on cryptographic communications, that is to say using an encryption algorithm offering very high security of identification.
• a few uses with the new phone are enough for the main parameters making up the signature to be determined; the additional parameters, for example when calling this telephone, being established during the predetermined period of the learning phase.
• FIG. 2 shows the layout according to the invention implementing a parallel type monitoring module for line protection.
• the telephone 1 has as close as possible to a security module 11 which, when it goes off hook, will identify itself with the central unit module 21 connected as close as possible to the central unit 2.
• the portion of line 4 enters these two modules is secure and the intrusion on this line will be detected by the central module 21 because the intruder 's telephone will not have transmitted the identification signals that the telephone module 11 transmits.
• the monitoring module 3 is placed in parallel on line 4 and analyzes the electrical signals.
• the identification module 5 connects to the line, at any location, and informs the monitoring module 3 of the change in the telephone to be protected.
• This invention is not limited to public telephones and this principle can also be applied to individuals. Indeed, they can be very interested in preventing the use of their lines by fraudsters. In this case, it is possible to store several signatures in the monitoring module if the individual has more than one telephone. However, avoid using cheap and readily available phones. To this end, the invention also extends to private type telephones for which it is possible to program a variation of the electrical parameters taken into account for the determination of the signature. This variation is a function of a key which can be entered either mechanically (selector with coding wheels for example) or numerically (via the keyboard). The individual will thus be assured that his phone is identified in a unique way although using a phone bought in a local store. The fraudster meanwhile, although in possession of the same phone will not be accepted by the monitoring module since the electrical parameters defining the signature will not have the same values as those of the authorized user.
• the monitoring modules advantageously have an alarm output indicating that an attempted fraud has been detected.
• This output can be connected to an acoustic generator or transferred to a monitoring table.
• several monitoring modules can be assembled to protect several lines.
• These modules are advantageously nestable not only mechanically but also electrically, that is to say that they have a connector for on both sides on which electrical signals are transmitted by an inter-module bus.
• Each module is linked to the two adjacent modules.
• a module called master is placed at the end of the series of modules.
• the inter-module bus includes a serial link for this purpose connecting the modules to the master module.
• the master module receives the status messages from the various modules making up the module chain to which it is connected via the serial link and transmits them to the alarm output.
• an acoustic signal is generated if any of the modules detects an attempt at fraud.
• the master module can have a modem (modulator-demodulator) allowing the transmission or the reception of information intended for all the modules, for example the state of the module, the counter of the number of attempted fraud, re-programming of parameters or software.
• modem modulator-demodulator
• modules are preferably supplied by means of a step-down transformer delivering an alternating voltage.
• this power supply is connected to each module via the inter-module bus. This voltage is galvanically isolated in each module, then rectified and filtered for proper use of the module.
• the monitoring module is equipped with a DOV (Data Over Voice) interface allowing the transmission of data between said module and the telephone to be protected.
• DOV Data Over Voice

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• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Computer Security & Cryptography (AREA)
• Telephonic Communication Services (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=4198483

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Family Cites Families (5)

• 2000
  • 2000-05-10 MX MXPA01011765A patent/MXPA01011765A/es unknown
  • 2000-05-10 EP EP00921002A patent/EP1179257A1/de not_active Withdrawn
  • 2000-05-10 WO PCT/IB2000/000623 patent/WO2000070850A1/fr not_active Ceased
  • 2000-05-10 GB GB0130157A patent/GB2366686A/en not_active Withdrawn
  • 2000-05-10 AU AU41400/00A patent/AU4140000A/en not_active Abandoned

Non-Patent Citations (1)

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