GB2047505A

GB2047505A - Decentralized call metering

Info

Publication number: GB2047505A
Application number: GB8008254A
Authority: GB
Original assignee: International Standard Electric Corp
Current assignee: International Standard Electric Corp
Priority date: 1979-04-14
Filing date: 1980-03-11
Publication date: 1980-11-26
Also published as: DE2915358A1; ES8200536A1; ES490554A0

Abstract

In a telephone exchange system it is often required to be able to assess call charges at a decentralized location, such as at a calling subscriber's instrument, e.g. a coin box telephone. Such an arrangement includes a reference number memory (7) which holds codes for all charging zones accessible to a subscriber using that telephone instrument. When a wanted number is dialled, it is placed in a register (2) and its prefix code digits compared by a comparator (3) with the stored codes, which are read out cyclically by addressing means 4, 5. When the code for the wanted number is read out, as indicated by the comparator (3) the latter stops the read out, the point in the read-out cycle at which comparison is achieved is indicated by the setting of a counter (4). The setting of this counter causes the selection of a generator (one of Z1, Z2 ... Zn), which supplies meter pulses appropriate to the wanted line's zone and thus its charging rate, to an evaluator 11. <IMAGE>

Description

SPECIFICATION Decentralized call metering This invention relates to the determinations of telephone charges at a decentralized location.

In today's coin box telephones connected to exchanges in countries with direct distance dialling, metering pulses are sent from the exchange to the telephone over the talking wires, which pulses are provided by central transmitter circuits and fed to the telephone via separating filters. In addition, the telephone set includes evaluating circuits, such as filters, threshold switches etc. The meter-pulse spacing depends on the respective tarrif zone, each of which is assigned a given time per monetary unit. The shorter the time per monetary unit, the shorter the meter-pulse spacing.

However, there are still countries in which long-distance calls can only be completed by operators. If, in such countries, long-distance calls have to be made without the aid of an operator and particularly from coin box telephones, and coin collection is to be automatic, it is necessary either to install meterpulse transmitters at the exchanges or generate the pulses in the individual terminals.

German Offenlegungsschrift (DE-OS) 2824627 discloses a meter-pulse counting facility which makes it possible to determine the charges for a call from a calling subscriber to a called subscriber. A coin telephone is assigned a tariff store for storing coded tariff signals which is addressed by an addressing device coupled to the "dialling" device. In the addressing device, the tarrif memory address is computed from the combination of the calling and wanted numbers. To determine the tariff, this known meter-pulse counting facility requires the numbers of the called and the calling subscribers. Such tarrif calculation using the two numbers is only possible in such telephone networks as are in use in U.S.A. where toll tariffs depend on the distance between the calling and called exchanges.The use of a co-ordinate system then makes it possible to calculate the distance between the calling and called exchanges, and so to determine the tarrif.

The Offenlegungsschrift also mentions that in telephone networks where the call charges are not directly dependent on the distance between the calling and called subscribers, a tariff store of especially large capacity is needed, which store must be large enough to be able to store many thousands of zone combinations and even more exchange combinations between which calls can be made.

An object of the invention is to provide a method which permits meter-pulses to be generated at a decentralized location, e.g. at a caller's telephone set.

According to the invention there is provided a method for determining the charges for a telephone call at a decentralized location and particularly in a coin box telephone which determines the charge associated with a dialled number automatically, wherein the prefix code (e.g. country code and/or trunk code) of the wanted number is compared with a plurality of permanently stored reference numbers, each said number corresponding to a plurality of possible prefix codes and has a given tariff zone permanently assigned thereto, and wherein if a reference number agrees with the prefix code number of the wanted number, the tarrif zone for this reference number is recognised, and the generation of corresponding meter pulses is initiated.

According to the invention there is also provided an arrangement for determining at a decentralized location the charges for a telephone call, which arrangement is associated with a telephone, e.g. a coin-box telephone, which has a memory for information for determining charges, wherein the information consists of reference numbers made up of prefix codes (e.g., country codes and/or trunk codes), wherein there is a register into which the number of a called subscriber can be written via an input unit, wherein the write register has one of its outputs connected to a first input of a comparator and the memory has its output connected to a second input of the comparator, wherein an addressing facility is provided which is connected to the address input of the memory to address the memory to read out the reference numbers therein, wherein the reference numbers thus read out are compared in the comparator with the telephone number in the write register, and wherein if the numbers fed to the inputs of the comparator agree, the comparator, in conjunction with an evaluating facility activates a particular meter-pulse generator whose output is connected to a meter-pulse evaluator.

An embodiment of the invention will now be described with reference to the accompanying drawing, which is a block diagram of an arrangement embodying the invention for generating meter pulses at a decentralized location.

Via an input unit 1, a calling subscriber enters the telephone number of a wanted subscriber, which number consists, for example, of a prefix code and the subscriber's number. The entry may be made in a manner not shown. The input unit 1 passes this number to the exchange in a manner not shown and transfers it into a write register 2.

This register 2 has an information output I, coupled to a first input of a comparator 3, and a control output connected to a counter 4 and a pulse generator 5. When new information is written into the register 2, its control output changes from the 0 to the 1 state. Hence, the counter 4 is enabled via its enable input EN, and the generator 5 is started via an AND gate 6.

The outputs of the counter 4 are connected to the address input A of a memory 7 and to an address-zone translator 8, which may also be called a "decoder". The memory 7 is addressed via the outputs of the counter 4, the addresses being obtained in the counter 4 by counting the pulses from the pulse generator 5 to the counter's count input Z. Thus the memory 7 is addressed cyclically.

The memory 7 is a read-only memory (ROM) and holds as reference numbers the prefix codes of all permitted toll connections (country codes and/or trunk codes, possibly with prefix), which are stored in suitably coded form. Using cyclic addressing all stored reference numbers can be interrogated, as they appear at the output of the memory 7 and are fed to a second input of the comparator 3. If, for example, a reference number read from the memory 7 agrees with a prefix code in the write register 2, the output of the comparator 3 changes from the 0 to the 1 state. Therefore the AND gate 6 is inhibited via an inverter 9, so that the start-stop input S of the generator 5 is 0, which stops the generator 5. The counter 4 thus remains at the count corresponding to the address of the "agreeing" reference number.The translator 8 assigns to this count or address a given tariff zone and selects one of its outputs 1 to n, assigned to this tariff zone. If, for example, the output 2 is selected, the AND gate U2 connected to this output is set to 1 at its input connected to the translator 8. The second input of this gate U2 is set to 1 by the output of the comparator 3, so that the output of U2 is at 1. This activates the meter-pulse generator Z2, which delivers meter pulses to a meter-pulse evaluator 11.

Each of the meter-pulse generators Z1 to Zn can provide meter pulses whose spacing is characteristic of a given tariff zone. Thus, one meter-pulse generator is provided for each tariff zone. The evaluator 11 does not form part of the invention, because evaluators have been used in coin box telephones for evaluating meter pulses for a long time.

The assignment of the tariff zones to the individual reference numbers may be performed in various ways. For example, the design of the memory 7 may be independent of the location of the telephone containing the charge-determining arrangement. Then the translator 8 must be individually available to each subscriber, i.e. depending on the location of the telephone, this translator 8 must assign given tariff zones to the addresses of the memory 7. It is also, of course, possible to equip all coin box telephones connected in the same local network with the same address-zone translators, i.e. to use individual translators for each local network.

The reference numbers in the memory 7 may also be distributed to given memory areas, so that each of these areas and thus the reference numbers therein are assigned to one tariff zone. Then, the address-zone translator 8 could always be of the same design irrespective of the location of the telephone, and would only have to evaluate the memory area. Dependent upon location, the reference numbers would have to be written into the areas corresponding to the associated tariff zones. In this case, each area would be permanently associated with one tariff zone.

Another way to assign the tariff zone to the reference numbers is to add to each reference number in the memory 7 a coded information item specifying the tariff zone for that reference number. This information can be evaluated by a decoder 1 2 connected to the output of the memory 7, which decoder 1 2 is indicated by broken lines. In this realization, the reference numbers in the memory 7 need information relating to the telephone's own tariff zone. The decoder 1 2 can always be of the same design independently of its location.

The address-zone translator 8 can thus be replaced by the decoder 12, whose outputs are coupled to the AND gates U1 to Un in place of the translator 8. The decoder 1 2 evaluates the tariff-zone information arriving at its input and activates the associated pulse generator, e.g. Z2, via one of its outputs.

At the end of a telephone call, the counter 4 is reset to zero, e.g. by resetting the write register 2, whose control output then changes from the 1 to the 0 state. Hence, a signal is applied through the inverter 10 to the reset input R of the counter 4, which is thus reset to zero.

Claims

1. A method for determining the charges for a telephone call at a decentralized location and particularly in a coin box telephone which determines the charge associated with a dialled number automatically, wherein the prefix code (e.g. country code and/or trunk code) of the wanted number is compared with a plurality of permanently stored reference numbers, each said number corresponding to a plurality of possible prefix codes and has a given tariff zone permanently assigned thereto, and wherein if a reference number agrees with the prefix code number of the wanted number, the tariff zone for this reference number is recognised, and the generation of corresponding meter pulses is initiated.

2. A method as claimed in claim 1, and wherein for the comparison with the wanted number, the stored reference numbers are interrogated cyclically.

3. A method as claimed in claim 1 or 2, and wherein each of the stored reference numbers has associated with it an item of information specifying the tariff zone of the wanted number.

4. A method as claimed in claim 1, 2 or 3, and wherein the reference numbers are stored in different memory areas, each of which memory areas has one tariff zone permanently assigned thereto.

5. An arrangement for determining at a decentralized location, the charges for a telephone call which arrangement is associated with a telephone, e.g. a coin box telephone which has a memory for information for determining charges, wherein the information consists of reference numbers made up of prefix codes (e.g. country codes and/or trunk codes) wherein there is a register into which the number of a called subscriber can be written via an input unit, wherein the write register has one of its outputs connected to a first input of a comparator and the memory has its output connected to a second input of the comparator, wherein an addressing facility is provided which is connected to the address input of the memory to address the memory to read out the reference numbers therein, wherein the reference numbers thus read out are compared in the comparator with the telephone number in the write register, and wherein if the numbers fed to the inputs of the comparator agree, the comparator, in conjunction with an evaluating facility activates a particular meter-pulse generator whose output is connected to a meter-pulse evaluator.

6. An arrangement as claimed in claim 5, and wherein the addressing facility addresses the memory cyclically.

7. An arrangement as claimed in claim 5 or 6, and wherein the addressing facility is a counter whose count input is connected to a pulse generator and whose outputs are connected to the address input of the memory.

8. An arrangement as claimed in claim 5, 6, or 7, and wherein the address-zone translator, like the memory has its input connected to the outputs of the counter, that n outputs of the translator are connected respectively to one input of each of n AND gates, the other inputs of the AND gates being connected to the output of the comparator, and wherein each of the AND gates has its output connected to an associated meter-pulse generator so as to be capable of activating this generator.

9. An arrangement as claimed in claim 5, 6, 7, or 8, wherein the output of the memory is connected to both the comparator and a decoder, and wherein the decoder by activating one of its outputs and in conjunction with the comparator can activate one of the meterpulse generators via the AND gates.

10. An arrangement as claimed in claim 5, 6, 7, 8. or 9, and wherein in case of agreement between the numbers fed to the inputs of the comparator, a zero state at the output of the comparator stops the addressing by turning off the generator.

11. An arrangement as claimed in claim 5, 6, 7, 8, 9, or 10, and which is housed in a telephone set and particularly in a coin box telephone.

1 2. A method of determining the charges for a telephone call, substantially as described with reference to the accompanying drawing.

1 3. An arrangement for determining the charges for a telephone call, substantially as described with reference to the accompanying drawing.