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

Definitions

• the invention relates to a method for generating metering pulses for a signal to be sent to a subscriber of a telephone system, said telephone system comprising at least one exchange and several subscribers connected thereto through several subscriber line interfaces, whereby during a call a number of metering pulses, said number being dependent on the call charging, are sent to those subscribers who have a call charge meter to indicate the price of the call.
• One auxiliary device that can be connected to a telephone of a subscriber line in a telephone system is a call charge meter.
• the call charge meter By means of the call charge meter it is possible to indicate the number of metering pulses to the subscriber and thus also the call price immediately after the call has terminated.
• Typical places where call charge meters are used are kiosks and bars where the customer may use a telephone against payment. When a call charge meter is used, the customer can be charged for the real costs immediately after the call.
• the call charge meter is typically connected to the subscriber end so that it is the first device as seen from the exchange.
• the call charge meter functions on the basis of metering pulses arriving from the exchange.
• metering pulses usually have a duration of approximately 200 ms and a frequency of 16 kHz.
• the call charge meter comprises a filter which filters off the pulses from the signal which is transmitted further to a telephone or another subscriber device via the call charge meter.
• Metering pulses are generated for example in the exchange or in another suitable place and the number of the pulses depends on the call charging. The higher the call charging is, the larger is the number of metering pulses per time unit. For example, according to the general principles applied in Finland the call price may depend both on the duration of call and on the distance of connection.
• a call may be charged by time, in which case metering pulses are sent at regular intervals.
• Another alternative is single-fee charging, in which case a number of metering pulses dependent on the call type are sent immediately at the beginning or end of a call.
• a combination of the above- mentioned modes may also be used, in which case a certain initial fee is charged at the beginning of a call and after this the call is charged by time till it terminates.
• the metering pulses to be sent to the subscriber's call charge meter are generated separately for each subscriber line interface, which renders the solution rather complicated since e.g. a separate metering pulse generator may be needed for each subscriber line interface.
• the object of the invention is to provide a method and an arrangement for implementing the method which allow to solve the above- mentioned problems.
• the object of the invention is achieved with a method which is characterized in that a metering pulse signal, which contains metering pulses at regular intervals, is generated in a centralized manner for several subscriber line interfaces and that the necessary number of metering pulses are applied to a subscriber from the metering pulse signal generated in a centralized manner.
• the invention is based on the idea that metering pulses intended for call charge meters of several subscriber interfaces are generated in a centralized manner by means of one generator, which produces a constant metering pulse signal in which metering pulses occur at regular intervals, and the necessary number of metering pulses, said number being dependent on the call charging, are applied to a subscriber from this metering pulse signal.
• An advantage of the method of the invention is that only one generator per several subscribers is needed to produce the metering pulse signal. Furthermore, since the necessary metering pulses are applied to a subscriber on the basis of the subscriber line interface, the generator may produce a standard signal. These features render the required apparatus simple and cheap.
• the invention also relates to an apparatus for generating metering pulses for a signal to be sent to a subscriber of a telephone system, said telephone system comprising at least one exchange and several subscribers connected thereto through several subscriber line interfaces, whereby during a call a number of metering pulses, said number being dependent on the call charging, are transmitted to those subscribers who have a call charge meter to indicate the price of the call,
• the apparatus being characterized in that it comprises a metering pulse generator, which produces a metering pulse signal which contains metering pulses at regular intervals for several subscriber line interfaces, and switching means for applying the necessary number of metering pulses to the subscriber from the metering pulse signal.
• This apparatus provides a simple structure for achieving the advantages of the method of the invention.
• Figure 1 is a flow chart of an arrangement of the invention for generating metering pulses for a subscriber
• Figure 2 is an envelope curve of a signal produced by a metering pulse generator of the invention.
• FIG. 1 illustrates an arrangement of the invention for generating metering pulses for a subscriber.
• a subscriber station 12 is connected to a subscriber line interface circuit (SLIC) 10 by means of conductors a and b of the subscriber line.
• the audio frequencies of conductors a and b are routed to the SLIC circuit 10, which sets the terminal impedance for the subscriber line and separates the signals of the transmission direction and the signals of the receiving direction from one another.
• the audio signal transmitted from the SLIC circuit to the exchange passes to a codec 11 via a filter 13.
• the A/D converter 111 of the codec 11 converts the signal into a PCM encoded form, whereafter the PCM encoded signal is transmitted further to the exchange.
• the PCM encoded signal transmitted from the exchange is converted in the D/A converter 112 of the codec 11 into an analog form and transmitted to the subscriber line interface circuit 10 via a filter 14.
• the other tasks of the subscriber line interface circuit 10 include feeding power into the subscriber line, feeding the ringing voltage and detecting the activation of a subscriber loop.
• Figure 1 further illustrates a metering pulse generator 15 which is used for producing a constant standard metering pulse signal.
• the metering pulse generator 15 may be located for example in the exchange or in another suitable place and the signal generated by it is divided between several subscriber line interfaces.
• Figure 2 illustrates the metering pulse signal generated by the metering pulse generator 15 schematically by means of an envelope curve.
• the horizontal axis 24 indicates time and the vertical axis 25 signal amplitude.
• the signal consists of substantially identical pulses (metering pulses) 20 having a frequency of 16 kHz and a duration of approximately 200 ms, and of pauses 21 between the pulses, the pauses having a duration of approximately 200 ms.
• the duration of the pauses 21 and metering pulses 20 and the frequencies of the metering pulses may vary in different telephone systems.
• FIG. 1 illustrates how a metering pulse generator 15 is connected to a subscriber line interface circuit 10.
• the signal produced by the generator 15 is supplied to the SLIC circuit 10 via a SLIC-specific switching device 16, which is controlled through a terminal CONT.
• the metering pulse signal is connected to the audio signal to be transmitted to the subscriber.
• the control signal may originate for example from the call control of the exchange.
• the metering pulse signal which is specific for a subscriber line interface, is generated from the standard metering pulse signal produced by the metering pulse generator 15 by applying the necessary number of metering pulses 20 at required intervals to the subscriber line interface by means of a switching device 16, which is specific for a subscriber line interface.
• the metering pulse generator 15 constantly generates a standard metering pulse signal.
• switching is started, i.e. the switching device 16 is set to the conductive state (closed) substantially in the middle of the pause 21 between the metering pulses 20. In that case the metering pulse signal can pass to the subscriber line a, b via the switching device 16 and the SLIC 10.
• switching is discontinued, i.e. the switching device is set to the non-conductive state (open) substantially in the middle of the pause after the last metering pulse to be transmitted. In that case the metering pulse signal cannot pass to the subscriber line via the switching device 16. Switching of a metering pulse/pulses is repeated at desired intervals. In the above-mentioned manner several independent metering pulse signals which are specific for a subscriber line interface can be obtained from one standard metering pulse signal.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Meter Arrangements (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=8549978

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (3)

• 1997
  • 1997-11-18 FI FI974276A patent/FI104932B/sv active
• 1998
  • 1998-11-17 WO PCT/FI1998/000902 patent/WO1999026388A2/en active Application Filing
  • 1998-11-17 AU AU12380/99A patent/AU1238099A/en not_active Abandoned

Patent Citations (3)

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