Franking system

Abstract

 Communication between a franking meter (29) and external peripheral devices (30,32,33) associated therewith is provided by means of radiation signals transmitted into the ambient environment of the meter (29) and devices (30,32,33). The meter (2a) and each device (30,32,33) is provided with a transmitter (20) and a receiver (21) connected to the operational circuits (10,25) thereof. It is preferred to use modulated infra-­red radiation. When satisfactory communication is prevented by obstacles, a satellite device (36) is provided to receive radiated signals from the meter (29) and other devices (30,32,33) and to re-transmit these signals either directly or after a delay.

Description

[0001] This invention relates to franking systems and in particular to systems incorporating a franking machine in communication with other devices or equipment.

[0002] Franking machines for printing franking impressions on mail items often are used in a stand alone arrangement without connection or communication with other equipment. The franking machines are provided with a keyboard for the input of data by a user and a display device for displaying the input data and data relating to the operational status of the machine to the user. However, it is sometimes desired to provide a system in which a franking machine is able to receive data inputs from other devices and in which the franking machine can output data to other devices. For example, with a stand alone franking machine the user would need to weigh a mail item, ascertain the appropriate postal charge for the item and then enter that charge on the keyboard to cause a frank of that value to be impressed on the item. However the weighing apparatus is connected to the franking machine data relating to the weight of the item can be input directly to the franking machine. The franking machine is provided with means to utilise the weight data to calculate a postal charge appropriate to that weight and the postal service required and to impress a frank. As a result manual input of the postal charge data by the user is not required. Instead of providing the franking machine with a keyboard and display device, the machine may be connected to, and be controlled from, a work station or personal computer. Franking machines are provided with a franking meter for accounting for postage value used in franking operations and for maintaining a record of credit available for use. Initially a credit register is loaded with a value of credit purchased for use in franking and when the value of credit falls to zero or a low predetermined value, further credit must be loaded into the register before further franking operations can be effected. This may be accomplished by taking the franking machine to a postal authority centre or, more conveniently, may be effected by means of a connection via the telephone network to the postal authority resetting centre. In some instances it is desired to construct the printing mechanism of the franking machine as a separate module or unit from the franking meter and hence it is necessary to provide communication from the meter to the printing mechanism. Thus it will be seen that increased convenience in use of a franking machine can be obtained by connecting the franking machine to other equipment such as, for example, a weighscale, computer or telephone network.

[0003] When a franking system comprising a franking meter and a number of external devices is installed in a work area, communication between the meter and external devices has been provided by means of electrical cables. Use of electrical cables tends to be inconvenient because the cables have to be tailored to the specific installation and have to be routed between items in such a manner that they are not hazardous to users of the system and do not interfere with handling of mail items in the work area. Furthermore if changes to the system are required, such as addition of items or re-location of items, the existing electrical cables may need to be replaced with new cables tailored to the new system.

[0004] It will be appreciated that in order to prevent attempted fraudulent use of the machine, the franking meter in a franking machine is constructed in a secure manner to prevent unauthorised access to the electronic circuits of the meter. To this end, the circuits are housed in a secure housing. Any connections to external devices need to pass through the wall of the secure housing and hence tend to reduce the security of the circuits within the housing and it is necessary to route all electrical connections between the exterior and interior of the housing via interface circuits designed to prevent application of excess voltage to the circuits of the meter.

[0005] According to one aspect of the invention a franking system includes a franking meter at a first location; at least one external device at a second location separated from said first location; said franking meter and each external device including transmitting means operable to generate radiation modulated by data signals and radiated into the ambient environment of the franking meter and external device and receiving means responsive to received radiation modulated by data signals.

[0006] If desired a satellite device may be provided to relay radiation data signals between the franking machine and the external devices.

[0007] According to another aspect of the invention a franking meter comprises a secure housing containing electronic means for carrying out accounting and control functions and input/output means for input and output of data respectively to and from the electronic means; a send transducer connected to the input/output means and operable by said electronic means to generate radiation modulated by output data signals from the electronic means and transmitted into the ambient environment of the franking machine; a receive transducer connected to the input/output means and operative in response to receipt of radiation modulated by input data signals to input said input data signals to the electronic means; a window in a wall of the housing, said window being substantially transparent to said radiation; and said send and receive transducers being located in the housing adjacent said window.

[0008] Preferably the radiation is in the infra-red region of the spectrum.

[0009] An embodiment of the invention will now be described with reference by way of example to the drawings in which:-

Figure 1 is a block circuit diagram of a franking meter,

Figure 2 is a block circuit diagram of a device for communicating with the franking meter,

Figure 3 is a diagram illustrating a franking system comprising a number of inter-communicating items,

Figure 4 is a block circuit diagram of a satellite device in which received signals are re-transmitted as they are received,

Figure 5 is a block circuit diagram of a satellite device in which received signals are re-transmitted after a delay,

Figure 6 is a block circuit diagram illustrating the checking of transmitted data signals, and

Figure 7 is a block circuit diagram illustrating a modification of the checking of transmitted data signals.

[0010] Referring first to Figure 1, a franking meter comprises a micro-processor 10 communicating via a system bus 11 with a keyboard 12, a display device 13 and memories 14, 15, 16 and 17. As is customary, the keyboard is utilised by a user to input data to the meter and the display device 13 is provided for the display of an echo of the data input on the keyboard and for the display of instructional data to the user of the meter, for example relating to the operational status of the machine and to accounting data maintained by the meter. Operation of the microprocessor 10 is controlled by program routines stored in the read only memory 16. The memories 14 and 15 are utilised by the microprocessor to store accounting data relating to usage of the meter for franking. In order to ensure integrity of the accounting data, data stored in one memory 14 is replicated in the other memory 15 and additionally data stored in each of the memories 14, 15 is duplicated. Accordingly each item of data is stored in quadruplicate between the two memories. The memories 14 and 15 provide a number of registers for storing different items of accounting data. A credit register stores a value of credit available for use in franking operations, a tote register stores a value of postage used in franking operations and an item register stores a count of the number of items franked. The memory 17 is a random access memory used as a working store by the microprocessor.

[0011] In order to permit signals from external devices to be input to the micro-processor and for signals from the micro-processor to be output to external devices, an input/output device 18 is connected to the system bus 11. While communication between the input/output device 18 and external devices may be by way of a multi-way plug and socket connection and electrical cables, it is preferred in accordance with the present invention to provide such communication by means of radiation links in which signals are transmitted from one device by a generator of radiation into the ambient environment of the devices and received at another device by a receiver responsive to that radiation. Accordingly the input/output device 18 is connected to a send/receive circuit 19. A send transducer 20 and a receive transducer 21 are connected to an output and input respectively of the send/receive circuit 19. In order to transmit data, the send/receive circuit energises the send transducer 20 such that the radiation generated by the transducer is modulated by the data being transmitted. The electronic circuit blocks of the franking meter are housed in a secure housing 22 to prevent unauthorised access to the circuits. A window 23 is provided in the wall of the housing and the send and receive transducers 21, 22 are located immediately behind this window. The window is constructed of a material which is substantially transparent to radiation transmitted by the send transducer and to radiation to which the receive transducer is responsive. The window forms a continuation of the wall of the secure housing and therefore the security of the housing is not breached as when an electrical connector extending through an aperture in the wall of the housing needs to be provided for connection to electrical cables. A power supply device 24, which may be powered from a mains electrical power supply, is utilised to energise the electronic circuits of the franking meter.

[0012] Figure 2 shows a block circuit diagram of an external device intended for communicating with the franking meter described hereinbefore. The device may be any one of a number of devices, for example a weighscale, computer, printer or modem, with which communication with the franking meter is desired. The device as shown in Figure 2 comprises electronic circuits 25 which are specific to the particular device for carrying out the functions of that device. If the device is a weighscale, the circuits 25 would include means responsive to weight of a mail item and for generating digital output signals representing weight data. The device may be provided with a keyboard and display to enable local operation of the device or the circuits include means responsive to receipt of control signals to enable remote operation of the device. A send/receive circuit 26, similar in construction and operation to the send/receive circuit 19 in the franking meter, is connected to the circuits 25. A send transducer 27 and a receive transducer 28 are connected to the output and input respectively of the send/receive circuit 26.

[0013] If the franking meter and external device or devices are located relative to one another such that radiation transmitted by the send transducers of the franking meter and the external device or devices is received by the receive transducers of the external device or devices and the franking meter respectively communication is established between the franking meter and the external devices and data signals may be transmitted therebetween.

[0014] It is preferred to utilise radiation in the infra-red portion of the spectrum for communication between the franking meter and external devices. However if desired the radiation may be of ultra sonic or radio frequency.

[0015] Clearly it is desirable to be able to locate the franking meter and external devices at positions which are most convenient to the user of the system, as is shown in Figure 3, in which a franking meter 29 and modem 30, for connecting the meter to a telephone network, are located in one part of an office 31 and a weighscale 32 and printer 33 are located in a mail handling room 34 separated from the office by a wall or partition 35. It will be understood that the radiation generated by a transmitter in the franking meter or an external device is transmitted into the ambient environment of the meter and external device and the transmitted radiation is not guided from the meter to the device or from the device to the meter. Accordingly the positions of the meter and external devices are not restricted by any need for physical connections therebetween. However in some instances there may be obstruction to transmission of radiation between the meter 29 and some of the external devices 32, 33, particularly if infra-red radiation is utilised, resulting at worst in no communication or at best in poor and unreliable communication. In order to overcome this problem, a satellite device 36 may be provided in a location such that reliable communication can be achieved between it and the franking meter 29 and between it and the devices 32, 33. The satellite device 36 receives radiation signals from the franking meter 29 and from the external devices 32, 33 and re-transmits the radiation signals to the external device and franking meter respectively. If desired the satellite may be utilised not only to re-transmit radiation signals but it may be connected to an external device. The external device may be adjacent the satellite and if desired the satellite and external device to which it is connected may be combined into an integral unit. On the other hand the satellite may be connected by electrical cable 37 to an external device 38 remote from the satellite, for example situated in another part of a building, to enable data signals to be transmitted between the franking machine and the remote device 38.

[0016] The satellite may be constructed as shown in Figure 4 and be operative to receive signals from the franking meter and from all of the external devices and to re-transmit radiation signals carrying the received data substantially simultaneously. Essentially the satellite comprises a receiver 40 responsive to the radiation signals to produce electrical signals which are input by connection 41 to transmitter 42 to be re-transmitted. The simultaneous re­transmission of radiation signals may result in interference between signals. If the radiation is infra-­red this is believed not to result in any problems. However if the radiation is of radio frequency, the interference may result in partial or total cancellation of the radiation signals. Accordingly in circumstances where simultaneous reception and transmission of radiation signals results in poor or unreliable communication, the satellite is constructed to delay re-transmission of radiation signals. For example, when radiation signals carrying data are received by the receiver 40 of the satellite the data is stored in memory 43 in the satellite and, after a delay determined by a control circuit 44, the data is read from memory 43 and modulates a carrier generated and transmitted by transmitter 42. Thus re­transmission of data is delayed until after receipt of that data so that reception and re-transmission are not simultaneous. It will be appreciated that, depending upon protocols utilised in communication, the control circuit 44 may cause re-transmission to be effected after reception of each complete data block or after reception of a complete message. The memory 43 is of appropriate capacity to temporarily store the data blocks or messages. When the satellite is connected to an external device 38 by means of a cable 37, signals from the receiver 40 are input to a driver 45 for transmission along the cable 37 to the device 38 and signals received from the external device 38 via the cable 37 are input to the transmitter 42.

[0017] Interference signals may result in corruption and loss of integrity of the data in transmission between the transmitter and the receiver. Accordingly in order to prevent such corrupted data from being accepted as data by the receiving device, a check on the data is carried out by the receiving device. This may be accomplished by causing the transmitting device to transmit each data block twice. The received blocks of a pair are compared for equality and if they are equal the data block is accepted. Figure 6 illustrates the writing of a data block received serially bit by bit in a first transmission thereof into a first register 46 while the data block received in a second transmission thereof is written into a second register 47. The data blocks written into registers 46, 47 are read out to a comparator 48. If the data blocks read from both registers are identical, the comparator outputs a data acceptance signal on line 49 to cause acceptance of the data block as being a valid data block. However if the data blocks from the registers are not identical, the comparator does not output the data acceptance signal and as a result the received data block is rejected and the sending unit will be requested to repeat the transmission of that data block.

[0018] Alternatively, the second transmission of a data block may be effected in reverse order to that of the first transmission of that block. The receiving device then compares the first transmission of the block with the second transmission but in reverse order. The data block in one register is read out in reverse order to that in which the data block was written into that register. As shown in Figure 7, register 47 is read out in reverse order. If desired each block of data may be transmitted with check sum and/or parity bits to provide an additional check on integrity of the received data block.

[0019] The franking meter may act as master device of the franking machine system and all communications may be controlled by and be to and from the franking meter. However if desired, one of the devices external to the franking meter may act as master device of the system and control communication between devices and between devices and the franking meter.

Claims

1. A franking system including a franking meter (29) at a first location; at least one external device (30,32,33) at a second location separated from said first location characterised in that said franking meter (29) and each external device include transmitting means (20) operable to generate radiation modulated by data signals and radiated into the ambient environment of the franking meter and external device and receiving means (21) responsive to received radiation modulated by data signals.

2. A franking system as claimed in claim 1 further characterised in that the radiation is in the infra-red region of the spectrum.

3. A franking system as claimed in claim 1 or 2 further characterised by the provision of a satellite device (36) including first receiving means responsive (40) to received radiation modulated by first data signals from the franking meter (29) or from the external device (30,32,33); first transmitting means (42) operable to generate radiation modulated by said first data signals and to transmit the modulated radiation to the franking meter (29) and the external device (30,32,33).

4. A franking system as claimed in claim 3 further characterised in that the satellite device (36) includes memory means (43) to store the first data signals of the received radiation and means (44) operative after reception of the first data signals to read the first data signals from the memory means (43) and to modulate the radiation generated for transmission to the franking meter (29) and the external device (30,32,33).

5. A franking system as claimed in claim 1 or 2 further characterised by the provision of a satellite device (36) including first receiving means (40) responsive to received radiation modulated by first data signals from the franking machine (29); first transmitting means (42) operable to generate radiation modulated by said first data signals received from the franking machine (29); and second receiving means responsive to received radiation modulated by second data signals from the external device; and second transmitting means operable to generate radiation modulated by said second data signals received from the external device.

6. A franking meter comprising a secure housing (22) containing electronic means (10) for carrying out accounting and control functions and input/output means (18) for input and output of data respectively to and from the electronic means (10) characterised by a send transducer (20) connected to the input/output means (18) and operable by said electronic means (10) to generate radiation modulated by output data signals from the electronic means (10) and transmitted into the ambient environment of the franking machine; a receive transducer (21) connected to the input/output means (18) and operative in response to receipt of radiation modulated by input data signals to input said input data signals to the electronic means (10); a window (23) in a wall of the housing (22), said window (23) being substantially transparent to said radiation; and said send and receive transducers (20,21) being located in the housing (22) adjacent said window (23).

7. A franking meter as claimed in claim 6 further characterised in that the send transducer (20) is operable to generate radiation in the infra-red region of the spectrum and the receive transducer (21) is responsive to radiation in the infra-red region of the spectrum.

Drawing