JPH0467827B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Field of Application The present invention relates to an electronic postage meter, and more specifically, a keyboard for inputting postage to be printed, a display for displaying postage to be printed together with other data, an electronic accounting device, and a printer. The present invention relates to an electronic postage meter having a mechanism. (b) Prior Art and Problems to be Solved by the Invention Apparatus of the type described above is generally known and is described, for example, in US Pat. No. 3,978,457.
This patent discloses an apparatus for a postage meter that includes a keyboard for manual entry of data corresponding to the postage to be printed. In conventional devices in the general category of providing electronic postage meter operation, it has been found desirable to use one or more microprocessors to control the various meter functions and operations. For security reasons, data regarding accounting is kept separate from other data regarding non-secure information.
By keeping secure data separate, it is possible to improve security through the concept of distributed processing through the use of multiple processors. The use of multiprocessing in a secure environment places stringent requirements on error rates in interprocessor communications, which must be met for satisfactory operation. Additionally, it would be desirable to provide a type of device that can easily replace the control authority for an external device. This allows virtually 100% control of the meter's functionality to be transferred to an external device without any changes to the system hardware. Also, the use of electronics in postage meters allows for more sophisticated capabilities in automatically recharging accounting registers without the need for manual action. Therefore, it is a desirable feature in any toll meter to provide an improved method for detecting tampering and performing self-diagnostic error checks. It is an object of the present invention to provide a distributed processing device for generating and printing postage values that maintains secure data separate from non-secure data. Another object of the present invention is to provide an interprocessor communication system that minimizes errors as a result of multiple interprocessor communications. Another object of the present invention is to provide an improved self-diagnostic error checking method. (c) Means for Solving the Problems The foregoing objects are achieved by providing a postage meter having two or more units, each with computer control, and further providing communication between the units. Communication between units is preferably minimized for safety, with no separate control lines between units, and all control signals appearing on the same data serial channel as the message data.
Another requirement is that the message be completely error-free upon receipt by the receiving unit to ensure the integrity of the postage device in error-free accounting of all postage. In an embodiment of the invention, the postage meter includes three units mechanically coupled together, each unit having a CPU and having a crystal controlled clock. In the present invention, the frequencies of the clocks of different units need not be the same, and interunit communication is by serial messages sent and received asynchronously. However, the format of the messages and the timing of the bits in the different units are precisely set to ensure that messages are sent and received without the need to synchronize the different units. Furthermore, upon receipt of the first bit of a message from the sending unit, this received bit allows the transmitter to authenticate the transmitted and received message in a minimum period of time following the transmission of the entire message. It is sent back to the transmitter by the receiver for comparison which allows to transmit "no error". All control and data signals use the same pair of conductors in each direction with precisely determined timing for control. To provide external control, the flow of control is in one direction and the flow of information is in the other direction. All control of the toll meter and all information within the toll meter is controlled by connections via interface connectors. All functions performed by the meter can be electrically controlled from a remote location, except for purely local manual functions such as powering on and changing the date. This is achieved through the communication capabilities of the data unit. The configuration of the three units is obtained by the flow of data commands or control from the control unit to the accounting unit and the printing unit. For example, the new value of postage and where it is set. The information flow is in the opposite direction, such as the current register value. Within this concept, external device connections, such as connecting an electronic scale to a control unit, can function to place commands or data control command information into the billing system. The interface operation can disable the e-board and allow an external device to take control of the meter. The external device can communicate messages to the display, thereby eliminating the need for the external device to include a keyboard and display. One particular advantage of the aforementioned component unit is that the control unit can be physically replaced by the attached external operating device without any changes to the accounting unit or the printing unit, either in hardware or software. . (C) Examples The present invention will be described in detail below with reference to the drawings. FIG. 1 shows a pace 21 according to an embodiment of the present invention.
A postage meter 20 is shown removably secured to. In this arrangement, a slot 22 for receiving an envelope or the like and printing postage thereon is provided between the postage meter 20 and the base 21 on the front edge thereof. The postage meter includes a control panel 24 as well as a display panel 23, preferably an electronic display device. This panel is constructed in the manner disclosed below. The device is powered by a power cable 25. The postage meter 20 shown in FIG.
The base 21 is of the type disclosed in, for example, Bach et al., U.S. Pat. It is. The separation of the meter and base makes the electronic rate meter compatible with conventional drive units, simplifies servicing of the equipment, and, if necessary, allows the meter to be used for recharging in the absence of remote billing capabilities. Make it easy to carry. Also shown in FIG. 2 is a postage meter panel. It can be seen that the meter is equipped with a numeric display 30, for example a conventional multiplexed seven segment LED or LCD display. Further, the keyboard includes a numeric setting key 31 for setting a desired amount of postage to be printed on the charge meter.
and a decimal key 32 operating therewith. This fee amount is normally displayed on the display 30. A clear key 33 is also provided for clearing the displayed amount, for example, in case of incorrect input. When the displayed amount is set to the desired value, pressing the set postage key 34 sets the postage setting print wheel. This panel further includes a series of keys that allow for the selective display of other values on the display 30. For example, pressing key 35 will display the contents of the ascending register, ie, the postage used by the rate meter, and pressing key 36 will display the contents of the rate meter's descending register, ie the postage the meter can still charge. will be held. Additionally, keys 37-40 each allow for the control or display of postage sum, piece count, batch value, and certain other specialized values, such as batch count, in a conventional manner. The batch value and batch count registers can be cleared by pressing either the batch value key or the batch count key and the clear key c at the same time. This panel also includes an LED 41 that is illuminated in response to the application of power to the meter, which typically occurs at the beginning of the day. this
LED 41 indicates that the date stamp is not set, that is, the date stamp door is open.
Another LED display 42 is illuminated when it is necessary to reset the trip mechanism in the base before continuing operation. In order to re-charge the toll meter, for example by means of a keyboard, the toll meter is provided with a key slot 45, shown in FIG. 1, into which a key 46, shown in FIG. 2, is inserted. The lock shaft is visible through the window 47 to indicate the position of the key. Thus, in the normal set of keys, this axis displays the message "operate" as illustrated. This device is also used, for example, in US Pat. No. 4,097,923
It can also be used for remote meter resets as explained in the issue. As another feature, the meter includes a service switch 50 at the rear end for the convenience of field service personnel to use the meter key for other functions. By the operation of switch 50, key 3
5 through 40 can display other values such as a non-fixed value, low postage warning amount, meter number, diagnostic status, and maximum settable amount. Enter the modified encoding combination on the keyboard while pressing the switch ``enter combination'' as shown in window 47.
When rotated into position, the meter is ready to perform a recharge mode, which can be achieved by an internal switch lock controlled by key 46. In this billing mode, as indicated by this message in window 47, the "enter amount" position allows entry into the meter's recharge value register by means of the keyboard. Returning the key to the operating position allows the meter to be reused to print postage. The service switch is in a non-warranted position in metering because the display of a different value made possible by the use of the service switch does not affect the meter's warranty and can simply display a different value. If desired, those values being displayed can be indicated by special underlining on the display, and operation of service switch 50 partially disables set postage key 34. When the postage meter is in the "service" mode, no new value of postage can be set in the postage meter, and the interposer operates to prevent operation of the meter in the service mode.
However, the set key can still be used to display the current set value. When the charge meter is in service mode, i.e. switch 50 is in operation, switch 45 and key 46 are activated.
When activated, entering a new value and a code indicating the location of this value on the keyboard will reset the non-fixed value, the low warning postage amount, or the maximum settable amount, respectively. The "unlock" value is a fixed value, for example $1, above which the operator must be careful in setting it to avoid accidentally printing excessive amounts. For this reason,
All values above the non-fixed value require an additional step on the part of the operator, such as pressing a further set postage key 34. The display includes a distinguishable indication, such as one horizontal bar, to indicate that the print wheel has been set but no further steps or SET POSTAGE keys have been pressed. Completion of an unfixed step is indicated, for example, by a three horizontal bar display, indicating that the meter can be tripped to print postage. If the descending register does not have enough funds to cover the set amount on the print wheel, the entire display will flash. Conversely, if the value stored in the descending register is less than the low postage warning limit, the decimal point will blink. Of course, the setting of any postage amount is "maximum configurable".
settable)” amount cannot be exceeded. The meter also includes a "privileged" switch 51, which is normally held in the operative position by a seal. Following the cutting of the seal, operation of this switch allows the postal worker to re-charge the meter in a non-remote billing mode. Additionally, the rate meter allows for changes to the postage setting metal prior to pressing the set switch 34, such as adding another value to the already displayed setting value. This feature allows the operator to introduce other values, such as insurance, etc., without the need for manual calculations or calculations by separate equipment. The internal elements of the postage meter of the invention are preferably arranged as shown in FIG. 1 compartment 55. It is not possible to give 100% guarantees in this regard, but physical evidence of tinkering is evident anyway before the input is obtained. Compartment 55 contains a printing module 56 containing a mechanical printing mechanism and can be provided with a separate microcomputer to control this module if desired. This compartment 55 also includes another electrically shielded compartment 57 containing an accounting module 58. This accounting module was installed in July 1978 in order to avoid accidental or intentional damage caused by the introduction of noise, e.g. excessive voltage into this accounting module.
It is connected to external equipment or the exterior of compartment 57 only by an optical or equivalent insulating coupler 59, as disclosed in US Patent Application Serial No. 918,785, filed May 26, 2005. Of course, such a coupling does not include an energy source connected to a power source 60 in a separate compartment 61 within the security compartment 55.
The power source 60 is connected to the filter 6 in the compartment 61.
2 to ensure that there are no voltage fluctuations that adversely affect the accounting module. Power input to compartment 61 is supplied into compartment 55 from a power supply in another compartment 63 defined by the external security housing of compartment 55. Thus, although it is not absolutely necessary that all elements within compartment 63 be physically secured, this feature is preferred. Power from main plug 64 is supplied to compartment 6
3, from which power is supplied by suitable connections 65 to power the meter base. Fuse 66 supplies meter power to compartment 63 from fuse 66 to thermostat 67 and to transient suppressor and filter 68.
It is fused inside. This thermostat inhibits the application of voltage to the device in case of excessive temperature.
Additional protection for the system is provided by isolation transformer 69 and overvoltage cutout device 70.
Power to the bill meter is ultimately supplied to a large capacity capacitor 7.
1 is supplied to an energy storage device 71 such as 1.
This capacitor 71 has a suitable energy storage capacity to enable a self-protection feature of the meter, which operates to transmit data to a non-volatile memory in the event of a power failure. The drop in voltage is detected by a sensor 72 within the security housing 55. One output of this sensor 72 is provided to the accounting module to signal the need for a mode change, and the other output (which may be a mechanical output) disables the functionality of another printing module. Another output of the isolation transformer 69 is sent to a control unit 75 external to the meter, and one of the isolation outputs of the accounting module is fed through the chamber 63 to the control unit. This control unit 75 consists of a keyboard control unit as shown in FIG.
Includes display etc. In this way, the third
The illustrated apparatus arranges each element of the postage meter such that elements that are not critical to the guarantee of the postage meter apparatus have physical and electrical guarantees for successive low levels. An embodiment of control unit 75 is shown in FIG. The device is preferably incorporated into, for example, a 6500 series central processing unit 80, for design versatility as well as minimizing non-critical elements that must be physically isolated within the security housing, and is Data lines, control lines and address lines allow normal multi-purpose RAM/
Connected to the ROM I/O timer circuit 81. The timer circuit incorporates ROM, RAM, timing control elements, and input/output interface hardware. By use of a suitable decoder 82, the keyboard 83 is scanned in a conventional manner;
Also, through the use of a suitable driver 84, the visual display 85 can be activated in a multiplexed mode with conventional plug-ins. Pressing any of the keys on the panel sends data to the associated data processing unit 80 and accounting module 58 within the warranty housing 55.
Serial input on line 86 to communicate with /
Generates output. Processor 80 and circuit 81
are indicators 42 and 41 of FIG. 2, respectively.
element of operator participation to reactivate the trigger mechanism in the base to selectively energize the indicator LED 87 corresponding to the date stamp door 28 (FIG. 1) following the application of power to the device.
respond to failure to open or close. Servo switch 50 is also connected to circuit 81. If other input/output devices, such as an external display device or a control device, are connected to the control device, these can be connected to separate input/output lines 88,
It is coupled to the device by a serial communication path, preferably suitably isolated by an optical isolator. The apparatus consists of an internal power supply and regulator 89 connected to receive power from the postage low voltage source as shown in FIG. The aforementioned functions under the control of the control unit are non-critical functions in the sense that loss of control or the contents of any registers will not result in a loss of funds to the post office department or to the user. These functions belong to the control unit since the security part of the postage meter includes only the programming of the system to be guaranteed. Additional functions performed by the control unit, such as addition of continuously entered amounts, may also be carried out without the calculation being critical to the security of the device and physically within the security portion of the postage meter. It is controlled by the program of the control unit. Similarly, service resettable functions are performed by programming within the control unit since these functions are also not critical to the accounting system and registers themselves. However, it is desirable to maintain these parameters in non-volatile memory within the accounting unit. Of course, it is clear that in a device such as that shown in FIG. 4, other arithmetic keys could be provided without great difficulty, such that the postage meter could be used as a separate calculator. Alternatively, the central processing unit and its control unit can be augmented with a calculator chip or the like connected to a keyboard and display to perform arithmetic functions. Although the control unit of Figure 4, which includes all the functions of the panel shown in Figure 2, is located directly to form part of the postage account, this part of the system does not physically This allows the postage meter itself to incorporate only those elements that need to be physically guaranteed. Since financial information and controls are common to serial communications used in devices, a high degree of integrity is essential. Therefore, the device is designed in a serial transmit communication section such that the transmitted bits are returned or "echoed" by the receiver for checking. This ensures that once the transmitter receives all the echoed signals, the transmitter will receive a "no error" signal.
error)” pulse, which sends information to the receiver that the received information is valid. The circuitry of the checkout compartment is shown in some detail in FIG. In FIG. 5, compartment walls 90 are shown forming an electromagnetic shield. The circuit includes an accounting microcomputer 91 having a non-volatile memory control 92 coupled to the microcomputer.
Non-volatile memory control controls the application of stored data between volatile memory forming part of accounting microcomputer 91 and non-volatile memory 93.
Volatile memory like RAM works in ascending registers,
Functions as a work descending order register, etc. The accounting microcomputer also includes ROM control for the necessary accounting routines as well as control routines. Additionally, this unit can incorporate a serial interface that allows for interfacing with printing and control modules. The microcomputer consists, for example, of the 8048 series microcomputer available from Intel Corporation, which has a control circuit in a manner similar to that described above for control unit 75. In order to avoid damage to the accounting module due to accidental or intentionally applied electrical surges and to eliminate electrical noise induced through the ground loop, the accounting microcomputer may apply voltage surges to the microcomputer. communication with equipment external to the compartment 57 by means of suitable isolators that cannot be used. These isolators are, for example, in the form of photoelectric couplers and are arranged so that they are not accessible from outside the postage meter. Isolator unit 94 has a two-way communication path with the control unit. Another isolator structure 95 provides a two-way communication path with the printing unit or printing module 56 of FIG. 3, particularly its microprocessor circuit. Another isolator 96 is provided to apply a power detection signal to the microcomputer 91. Additionally, an isolator 97 is provided to control an interposer (not shown) within the printing module, for example to mechanically block the functionality of the printer. Such mounting was invented by R.Mc Figgans and A.Eckert, for example.
No. 024,812, filed March 28, 1979, and assigned to the assignee of the present invention. This disclosure is specifically incorporated herein by reference. In the current state of the art, non-volatile memory 93 is a MNOS which does not require a backup power supply.
It is a form of memory. However, this memory can be formed from elements that require separate power backup. A power control circuit is then used to provide backup power. The purpose of the power control circuit 98 is basically to perform data transmission operations during power-up and power-down.
The purpose is to provide power to MNOS memory. The program of the microcomputer unit 91 is configured to input the contents of the registers of the computer unit into non-volatile memory as soon as a power failure indication occurs, and to restore this data to the working registers upon restoration of power. has been done. Thermostat 67 in FIG. 3 shuts off power to the meter in the event of high or low temperature operation. This automatically places the meter on its power down cycle as a result of a power outage. Compartment 57 may further include suitable circuitry (not shown) coupled to, for example, a microcomputer.
It includes a temperature sensor 99 that transmits data to a non-volatile memory in the event of excessive temperatures having a temperature. The system further provides an isolator 9 in case of excessive temperature.
7 operates to prevent the interposer solenoid from operating. The interposer also uses a microprocessor to inhibit printer operation if there is insufficient postage remaining for a printing operation or if other accounting indicates that the unit is not operational. It is controlled by a computer 91. Although the isolators are shown as independent units, it is of course clear that these units can incorporate multiplexing devices so that two-way communication is established in each circuit. Additionally, systems for transmitting data between volatile and non-volatile memory are well known and are disclosed, for example, in pending U.S. Pat. No. 8,896, filed March 24, 1978. . FIG. 6 shows a detailed block diagram of an embodiment of the control unit of the invention. In this figure, blocks are identified by part number and application terminal. This unit is of type 2716PROM102
Similarly, RAM/ROM I/O timer circuit 10
1 is shown incorporating a Type 6503 CPU 100 with data and address lines coupled to one. PROM 102 stores therein a program for the control unit. Control lines such as interrupt lines and read/write lines are also connected to circuit 101. circuit 1
01 has multiple ports as described. The control unit further incorporates a keyboard 103 including numeric keys 31, display keys 35-40, and three position switch 45 shown in FIG. This unit is also add-through.
key 52 and set postage key 34. All of these keys and switches are connected in a matrix to the circuit 101 in a conventional manner to enable scanning of the keys and switches on a programmed basis to detect key or switch closure. 4 of port B of circuit 101
Like line, 8 line port A also has 7 segment display panel 1 for multiplexed display.
04 in the usual way. circuit 101
is further connected by a pair of serial ports for communication to and from the accounting unit. Additionally, a pair of additional serial ports enable communication to and from external devices via opto-electric isolators 107 and 108, respectively. Another output port of the adapter is connected to an LED 109 on the display panel that indicates that the date stamp door was not closed. Another output port is connected to an LED 110 on the display panel indicating that operator participation is required to reactivate the trigger mechanism on the base. Finally, another port is coupled to a service switch 50 which enables the functionality of the postage meter in service mode. In an embodiment of the invention, the program of the control unit is directed to the service of the keyboard unit, display panel, etc., so that the control functions and data storage are first carried out in the accounting unit. This allows the program to include the necessary functions such as keyboard scanning, display multiplexing, and signal formatting for communication with other units and external devices so that any new information is sent to the accounting unit. A typical opto-electric isolator is shown in FIG. It primarily consists of a conventional 6N136 device 115 containing a solid state emitter that generates an optical signal that is received by a photodiode. The photodiode is connected to the base circuit of the transistor amplifier. A block diagram of an embodiment of the accounting unit is shown in FIG. Figure 8 shows the type 8039CPU120
is shown, and photoelectric isolators 121 and 1
22 communicates with the control unit and serially communicates with the printing unit via opto-electric isolators 123 and 124. The optoelectronic isolators 121 and 122 in the accounting unit are thus directly connected to the corresponding leads of the control unit. Isolators 123 and 124 are connected directly to the signal channel of the printing unit, since no further isolator devices are needed for this purpose.
Furthermore, a control opto-electronic isolator 125 for controlling interposers and the like in the printing unit is connected to another port of the CPU 120. A signal corresponding to a pending power supply failure is separately sent to the interrupt port of CPU 120 by opto-electric isolator 126 .
It is clear that all signals and controls to and from the accounting unit must be provided by opto-electric isolator 126 to ensure the electrical and physical integrity of this unit.
The accounting unit further includes a plurality of PROMs 12, each of EPROM format 8755, for example, connected to the address and data lines of the CPU 120.
It has 7. This unit acts as a non-volatile memory to store data while the postage meter is malfunctioning or intentionally disconnected.
Connected to an EAROM 128, for example type ER3400. The working memory for the accounting system, including registers that store all working data, is on the CPU 12.
0 is provided. This data is transferred to EAROM 128 such as when a power drop is detected. In order to ensure complete transfer of data, a storage capacitor is connected to store adequate power to ensure proper functioning of the circuit in the usual manner until the transfer of data is carried out. FIG. 9 shows an embodiment of the circuit of the printing unit. This circuit is mainly used for example type 8748-8
It consists of CPU130, which is
30 is connected to I/O devices within the printing unit itself by suitable buffers where necessary. Mechanical and photoelectric detection devices within the printing unit are conventional and generally disclosed in, for example, U.S. Pat. No. 4,050,374 and copending U.S. patent application Ser. It is in the form of Thus, the CPU is connected to a plurality of photoelectric sensors (not shown) that detect the position of the print wheel. These lines are also connected to enable detection of the privileged access switch of FIG. Privileged access switch 51 is located within the printing unit and can only be accessed by a door sealed by the Post Office. These lines of CPU are further connected to detect the date stamp door position. The date stamp door switch and privileged access switch are strobed by separate outputs of the CPU 130. for optical sensors
The LEDs are strobed at the appropriate times by another output of the CPU 130 and a further output of the CPU which can step the bank and digit step motor for the print wheel. In addition,
CPU 130 has a pair of ports for serial communication to and from the accounting unit. Interposer output from accounting unit and
Another output of CPU 130 controls a pair of transistors 131 which energize the interposer solenoids so that interposer 153 is not energized until all predetermined conditions are met on both the accounting and printing units. as a result,
A printing cycle cannot begin unless the physical and electrical conditions of the meter are correct for successful printing. It is clear that in printing units the program for this purpose is provided within the CPU itself. Postage meters of the type described above have several variations. For example, in some versions, remote charging features are available whereby a key is provided to operate a three position charging switch on the keyboard. The operator of this unit thus has the appropriate combination of keyboard inputs to enable remote billing (ie, far from the post office). In such units, privileged access switches are omitted. In another variant, three positions on the keyboard,
The recharge switch is controlled by a single knob without the need for a key. In this type of system manual recharging is possible at the post office of the meter, but the service function is partially performed in the same way as the service function of an RMRS type unit. In other words, if the device is equipped with a key for a three-position switch, postage meter recharging of the type described above may be carried out locally, in which case a separate guarantee is provided as explained below. required. Conversely, in postage meters that have a single knob switch instead of a key switch, a "privileged access" sealed at the post office is provided for annual recharging. As previously mentioned, in normal mode operation of the device, the six display keys, when pressed, effect the display of the six parameters mentioned above on the display panel. namely, the sum in the ascending register of all postage printed, the sum remaining in the descending register of available postage, the controlled sum, the total number of printing operations of the rate meter, the value of postage printed, and The number of pieces printed since the last batch clear operation of the associated register is displayed. Pressing these keys occurs as many times as the concern is displayed for a certain time interval, say two seconds, after the key is released. After this 2 seconds the display will return to postage settings. In either type of meter, the display function of the display keys is different if the three position switch is still in the operating position and the service switch is placed in the service position. In this way, the "postage used" key 35
Pressing causes a display of the current value set in the dollar non-fixed register within the device, above which the operator cannot print postage. Postage values greater than this value require additional presses of the Set Postage key to operate to avoid inadvertently printing excessive postage values. "postage unused"
Pressing key 36 causes the display of the value in the low postage warning register, which is given a warning that the contents of the descending register are less than a certain amount. Pressing the control or "postage sum" key 37 causes the display of the serial number of the postage meter. Pressing the "piece count" key 38 results in a display of the meter's diagnostic status. This display gives service personnel an indication of possible malfunctions. Pressing the "batch value" key 39 results in the display of the maximum settable amount, i.e. the maximum amount set internally in the charge meter, above which the charge meter cannot set the print register. . Pressing the "batch conut" key 40 has no effect in service mode. The three position switch is used to perform a charge meter recharge or change the values in the registers relating to dollar non-fixed values, low postage warning amounts and maximum settable amounts. If it has the characteristics of a remote recharge device,
Positioning the three-position switch in either the "enter combination" or "enter amount" position allows the customer to enter the combination or amount, respectively, during billing by means of the keyboard and instructions on the display. Allows you to enter the amount. Leaving this position enters the display value into the accounting unit and leaves the display blank for the next entry. Returning the three position switch to the operative position causes the accounting unit to complete the recharging routine and returns the meter to normal use with the recharging amount added to the unused postage register. The combination for the remote recharge device characteristics is a random or pseudo-random number obtained from the remote recharge device data sensor and changed with each recharge for guarantee purposes. For meters with manual recharge device features, the recharge mode is implemented by breaking the seal on the privileged access door and flipping the privileged access switch. To recharge the meter, the same sequence of operation of the three-position switch described above is carried out as in those meters having the feature of a remote recharge device. Only postal workers are allowed to make changes on manual recharge machines. This combination is a fixed number known only to the post office and is stored in the billing system. Once the privileged access switch is returned to the operative position, normal operation of the meter can proceed. To change the values in the registers for dollar non-fixed values, low postage warning amounts, and maximum settable amounts, the service places the meter in service mode by placing the service switch in the service position. A three position switch is used as described above to enter combination and monetary values. The meter will interrupt the combination value to indicate which register should be changed. For the meter of the remote recharge device and the meter of the manual recharge device, if there is an error during input, the occurrence of this error is counted as evidence that the device has been tampered with. When such an error occurs, for example, nine times, the final set number of the meter, the functionality of the device in recharging postage is inhibited. Returning the meter to operation in such an environment occurs at the post office. The description of how to return the meter to operation is not important to the invention and does not concern the safety of the meter. As previously mentioned, each of the three units of the postage meter includes a microprocessor with a ROM that defines a predetermined program, and communication between the units is serial and asynchronous. This is accomplished in the first place by providing each computer system with a crystal controlled clock. Furthermore, the signal is defined such that its variation is tightly controlled to ensure that the signal, if present, is within a predetermined period of time. As a further guarantee of communication accuracy, the bits of the signal are returned to the transmitter upon receipt for error checking in the transmitter, which guarantees a ``no error'' bit if the data continues correctly. is sent immediately following the data message. The control unit program is responsive to the status of the postage meter for predetermined parameters. A register in the accounting unit's microprocessor holds, for example, two bytes of meter status information. The bit indicates whether the meter trip mechanism requires a restart, the date stamp door was not opened following the last application of power, or is currently open, or the amount set in the print wheel is not printing. There are not enough funds to authorize, the low postage value has not been reached, or the meter is in service mode.
Digitally indicates whether the charge meter is available, batch registers are clear, trips are complete, or various types of errors have occurred. The status messages associated with these bits are not the same as the diagnostic messages described above used in service mode. The accounting unit keeps the control unit aware of the current status by sending status messages to the control unit after it has been switched on, so that whenever a change in status occurs thereafter, the control unit displays the charge accrual display. It responds to all such messages by ensuring that the message consists of a status message as described above. These latter steps may include, for example, the display of a decimal column in the case of certain errors, the blinking of the decimal point in the case of low postage funds,
If there is insufficient postage, the entire display will blink, and if the meter is in service mode, the blank area will be underlined. An interrupt program in the control unit interrupts the control unit's main program at regular intervals to scan the keyboard and keyswitches and to drive the display. To prevent parasitic characters caused by leakage current from being displayed when multiple keys are pressed, the interrupt program instead causes the display to go blank. At the same time, values for the keyboard and keyswitches are maintained by the interrupt program for use by the main program controller program. The main program for the control unit includes an initialization step and the following program steps. i.e. steps to transfer information back and forth between the accounting unit and external equipment, steps to control the time display, check status messages to ensure that the date stamp door and reset base lights are illuminated according to their status. a step in response to the reported position of the key;
and a three-position switch step to confirm the change of state. As a result, the control unit subroutine corresponding to the function determined for this state or change of state is executed. The accounting unit's program, as well as the power down processing program which sends data to non-volatile (electrically changeable) memory in the event of a power outage or lack of power, detects whether working registers have been updated or not accounted for. Includes an initialization procedure to ensure that no postage is printed. The main program of the accounting unit sends meter status messages to the control unit as necessary or in response to changes in status, determines the execution of the currently entered postage value according to the currently registered funds data, and updates the status. Make any necessary changes in the message. The main program also controls the timing in the accounting unit to receive messages from the control unit and printer. The accounting unit program contains subroutines in line that handle signals during register updates when the postage meter is to be printed, and that control the operation of the system when the postage meter is tripping. Another subroutine controls updating of rate status messages. Furthermore,
Error checking routines, including cyclic redundancy checks, are programmed into the accounting unit's software. This is explained in more detail below. The printer unit program includes an initial setting step, a step to scan the sensor, a step to control the strobe for the sensor LED,
and a main program having steps for processing messages that communicate with the accounting system.
Subroutines are provided for postage wheel settings to determine if the sensor readings are correct and to determine what changes have occurred in the outputs of various hardware sensors and switches, such as privileged access and date stamp door switches. There is. As previously mentioned, for programs that set display non-fixed values, maximum settable amounts, and low postage amounts, the keys effective for such settings in the manner described above are arranged in a matrix on the keyboard and change state. is scanned periodically to determine if an event has occurred. A scanning position is also generated for the service switch within the control unit, whereby any key and switch control is communicated to the accounting unit for its internal storage and processing. for example,
The service switch is set to the on position, and then the scan, which is also effective for a three-position switch, is made available as a display routine;
Depending on the position of the three-position switch, a combination routine or an amount routine is entered. In the display subroutine, the data in the register corresponding to the pressed display key is sent to the control unit for display. In the input combination subroutine, the next input on the keyboard is memorized so that the value entered on the keyboard when the three-position switch is turned to the input amount position is stored in the corresponding register in the CPU of the accounting unit. such entered values are used for subsequent operation of the device during normal operating procedures. Of course, during normal operation, testing of the setpoints can be effectively performed over a range of values, such as a range of postage values less than or greater than the stored amount, so that the necessary indications are provided. The term "indication" as used in this sense means a representation. When the input postage value exceeds the maximum settable amount, the input value is ignored and the display returns to the original postage value. The service configurable characteristics described above may also be in different states, such as an inactive state when the maximum configurable value is exceeded, a low value warning state when the low value indication is flashing, and the setting of the amount in the display. It is conceivable to carry out control of the postage meter into a dollar non-fixed value state, which requires further presses of the set key when the stored value is exceeded. Regarding device diagnostics, briefly touched upon earlier, two basic error checks are provided in the meter's software routines. These two checks are called a fatal check and a procedural check, respectively. Under the category of critical error checking, two subcategories have been determined. These two subcategories are called hard errors and soft errors. Hard errors are determined by monitoring hardware sensors such as bank and digit selection sensors, interposer position sensors, shutter bar sensors, and the like. Failure of these sensors to give correct readings is called a critical hard error, which locks up the meter and cannot recover upon power-up. Intervention of a central authority is required to perform other operations of the meter. Another example of a serious hard error is a non-compare result from a cyclic redundancy check.
It is. Each data register is continuously monitored. Using standard polynomial methods, a cyclic redundancy remainder is calculated for each updated data register value. When a power down cycle is initiated, the contents of each data register and the associated periodic redundancy remainder are transferred to non-volatile memory. On power-up, each data register period redundancy surplus is calculated again and compared to the previously calculated period surplus on power-down. Non-comparisons generate serious hard errors. A serious soft error is related to the local communication capability of the meter unit. Thus, communication errors between internal units such as the accounting, printer and control units are detected based on the bit retransmissions described above. Furthermore, a communication time-out feature is provided so that failure of a unit to communicate within a specified period will result in a serious soft error. A severe soft error will prevent the meter from operating. Cancellation is performed by recycling the fare meter. That is, the meter is turned off and then turned on again, thereby recycling and clearing the error.
Power cycles are counted in a data register and, as previously described, once a predetermined number is reached, the entire operation can be frozen if desired. In other words, the predetermined number of critical soft errors is equal to one critical hard error. Procedural errors, such as incorrect entry of (high) values or incorrect procedures attempted, appear as visible flags on the display. Other diagnostic tests, along with the changes set out above, can be easily adjusted within the software routine being executed. By allowing data to be communicated serially between units on a message basis and by using the "echo" method described above, the implementation of the error checking capabilities described above is quickly accomplished. As previously mentioned, inter-unit communications are, for example, 9600 baud, serial channel, bit periodic, character aperiodic, start/stop communications. This communication is solely by means of messages. That is, no separate control lines are provided between the units for communication control. This type of communication is also provided for communication between the control unit and external devices. The message is 10 bits long,
Each includes a start bit with an 8-bit word or byte and terminates with a stop bit.
The last stop bit in a message has a direction opposite to that of all other stop bits in the message to indicate the end of the message. A logic zero indicates a start bit, end of message bit, and data zero or low. A logic 1 indicates the presence of a request to transmit, clear to transmit, end of byte, data 1 level, and no error pulse. The first word of any message has an encoded two-bit field indicating whether the message contains information, data, or control functions. 1st
Another bit in the word indicates whether the message pertains only to the display or only to the accounting unit. The remaining bits of the first word are specific message identification bits. If the message is larger than one word, the second word of the message contains a format byte consisting of two nibbles or groups of four bits. The first word of any message has an encoded two-bit field indicating whether the message contains information, data, or control functions.
Another bit in the first word indicates whether the message pertains only to the display or only to the accounting unit. The remaining bits of the first word are specific message identification bits. If the message is larger than one word, the second word of the message contains a format byte consisting of two nibbles or groups of four bits. The first nibble indicates the number of nibbles in the data of the message, and the second nibble gives the number of digits to the right of the decimal point in the data, or 16 if there is no decimal point.
Corresponds to base F. When a message is ready to be transmitted by a unit, the unit's receive lines are first tested. If it is low, the transmitter will raise its transmit line high and test the receive line again. If the receive line is still low, the unit must be removed from transmitting and become the other receiver. This avoids contention between the two units. As for the postage meter itself, in case of a possible conflict, the programs of the different units will give priority to the printer unit, the accounting unit, the control unit or the external device in that order. When an external device is interconnected with the postage meter or control unit, this control unit is given priority. The timing of messages is of paramount importance in communication systems, which causes messages to be asynchronous. Typical timing is illustrated in FIG. 10, which shows the relative timing on the line of a transmitter transmitting a given message and the line of a receiver receiving the same message. The output line of the transemitter is the same as the input line of the receiver, so these two
It is clear that the two signal lines are identical. Of course, the same applies to the transmitter input line and receiver output run-in. In this type of continuous transmission system, the transemitter tests its input line at time t ₁ and, if a low condition is detected, switches its output line for 50 microseconds as shown at time t ₂ . Rise high within range. Then Transmitsuta again 50
Test that input line at time t ₃ within -100 ms. If the input line is still low, the transmitter begins transmitting the message at time _t5 following a minimum waiting time of 120 microseconds by bringing this output line low to form the start bit of the message. be able to. Along the way, at time _t4 , the receiver raises its output line to a high level indicating it is ready to receive data for a minimum of 100 microseconds. This indicates a "clear to send" condition. The timing between subsequent bytes of a multi-byte message, as indicated by the time interval between t ₅ and t ₅ ', is such that the timing between subsequent bytes of the multi-byte message is available for the receiver to perform proper reception and storage of the signal. To ensure that the minimum is 1134375 microseconds. The time from the start of the last message byte t ₅ ' and the transmission of the no-error pulse at time t ₇ is
set to 103215 to 1157291 microseconds, and the no-error pulse is set to 309375 microseconds to
It has a width of 368228 microseconds. The receiver tests for the occurrence of a no error pulse between 1187291 and 1340625 microseconds at time _t8 following the onset of the start pulse of the last byte of the message. Transmitter bit transmission must be according to the table and receiver sampling of data and stop bits must be according to the timing shown in the table.

【table】

The timing described above allows the use of crystal control for the clocks of each unit's asynchronous transmission, so that control leads between units for this purpose are unnecessary. Additionally, in accordance with the present invention, data is continuously returned to the transmitter on the receiver output line to ensure that the information is accurately received by the receiver without error. From the beginning of the instruction loop detecting the start bit, the times for retransmission of data are given in the table. The time to sample this data to the transmitter on the input line is given in the table.

【table】

【table】

[Table] If the received data at the transmitter is the same as the transmitted data, and only in this case, a no-error pulse is sent at the end of the message. Another control over message communication is that the transmitter waits 3.5 milliseconds for a clear signal from the receiver to send after a request to send occurs, and similarly the receiver starts a message after a clear to send message occurs. up to about 3.5
Wait milliseconds. Contention between units is further minimized by establishing a predetermined period of time that must exist between the operation of unit adjacent transmitters as well as between adjacent receivers. All control and data signals use the same pair of conductors with precisely determined timing of control in each direction. To provide external control, the flow of control is in one direction and the flow of information is in the other direction. All controls on the toll meter and all information within the toll meter are provided via the interface connector at line 8 in Figure 4.
Controlled by connections along 8. All functions performed by the meter can be electrically controlled from a remote location, with the exception of purely local manual functions such as power on and date change. This results from the communication capabilities of the data unit. The software routine scans for the presence of an external control device and, upon recognition of its validity, authorizes such external device to assume control. The three unit configuration provides a control flow of commands or data from the control unit to the accounting unit and the printer unit. A new value for postage and where it is set is one example of such data and commands. The information flow is in the opposite direction.
For example, the current register value. Within this concept, external device connections, such as connecting an electronic scale to a control unit, can be operated to generate commands or data control command information during bill accounting. That is, the control signals given to the control unit include a transfer control command for directly transferring the contents of the register of the accounting unit of the postage meter to the control unit, and a transfer control command for causing the contents of the display of the postage meter to be directly transferred to the control unit. and control instructions for performing a complete transfer of control of the postage meter.
Operation of the interface allows external devices to take control of the meter, including disabling the control unit's keyboard, if desired. The external device interfaces with the meter on a message basis. The external device can send messages to be displayed or to request the contents of the display. Programming of the control unit allows external devices to send messages to disable the keyboard, thereby performing surrogate functions. One particular advantage of the above-mentioned configuration is that the control unit can be physically replaced by an attached external operating device without any changes in the accounting unit or the printing unit, either in hardware or software. be. External devices can include multiple operating devices such as scales and remote displays. The control unit's microprocessor is used to provide development flexibility and to function as a message buffer to allow the use of external devices. The external device may typically include a meter, display, or other type of device that interfaces with a fare meter of the type disclosed herein. Software provided within the control unit can perform this function. As shown in FIG. 11, an external device 150 is used to replace or supplement the functionality of the control unit. External device 150 is preferably a standard 9
It is coupled to a rate control unit 154 by a pin connector 152 to receive messages from the rate meter unit 152. The circuit diagram for meter unit 156 includes an accounting unit and a printing unit as previously described. The control unit includes a communication buffer 158 for logically directing communications from the meter unit 156 to the external device 150 or locally to the control unit 154. The opposite effect is shown in FIG. 12, where an external device communicates with the unit via a communication buffer. The effect is similar in that the buffer receives messages from external device 150 or locally from control unit 154. A plurality of external devices 164 are shown in FIG. 13 and interfaced to the meter unit via control unit 154. Each external unit has its own control key for message initiation. Each external device includes a communication buffer that enables operation of the external devices in a chain as part of the software. Suitable messages include complete transfer of the control unit's logic to the external device. The programming of the control unit is designed to allow such operation. Regarding the operation of the external device, information flows in two directions, one to the meter and the other to the external device. Control signals and requests, commonly defined as controls, flow inward toward the charge. Control of the information data takes place within the control unit. However, due to this feature, the present invention allows the external device 150 to issue commands to the meter unit via the control unit. Conversely, outbound information data from the metering unit (accounting) is provided to control unit 154 and repeated on external device line 152 to external device 150, if an external device is present. The presence of external device 150 is determined by whether it responds to a clear to signal. If not, the output on line 152 is turned off after a preset time period (timeout) and the meter continues to function normally. This ability to have a communication buffer and send information to the control unit allows for the advantage of having external devices on it. The external device has a communication buffer and is configured in the same way as shown in the control unit. The device in turn has an external device coupled thereto. In this way, a petal-like chain of external devices 164 is provided as shown in FIG. The only limitations on the number of external devices that can be coupled in this manner are system tolerances and timeout limits. Another feature of the invention is the provision of an external device to provide certain commands to the control unit itself.
This command performs functions within the accounting module, such as the ability to write a message to or read a message from the control unit's display, or command the control unit to disable the keyboard and rotary 3-position switch. It's not something you necessarily need to go. In doing so, the communication buffer is responsive to the beginning bit or header of a digitally transmitted message sequence to direct whether the message is to go to the metering unit or to the control unit. As mentioned above, this bit with assigned location in the heading is assigned its location '1' if the message is to or from the control unit, and '0' if the message is to or from the metering unit. Assigned. In this method, when the control unit receives a message from an external device, the control unit examines the header and determines from this bit whether the message is going to the control unit or to the accounting unit. If it goes to the control unit, the control unit stops the message and takes appropriate action. If not going to the control unit, the message is interrupted by the metering unit. The control unit may, for example, in response to receiving a message reading the display, provide a reply directly to the external device without involving the metering unit at all. The control unit does not retain the last meter status message received. For example, when a keyboard disable command is received, the control unit requests a meter status message from the accounting unit. When the control unit gets a response, it inserts one bit into the meter status message to indicate whether the keyboard is enabled or disabled. Once disabled, the control unit continues to indicate the disabled state in status messages until reset by receipt of a keyboard enable command or until power is turned off and on. The keyboard is always ready for use when powered up. The toll meter can thus interface directly with external devices, something which is difficult to achieve with the present toll meter. In summary, the control unit is equipped with connectors for two-way communication with various external devices. This allows external devices to receive meter information such as register readings, piece counts, and current value selections. Furthermore, an external device can control the meter to the same extent that an operator can control it by a keyboard. The rate meter may include attachments to automatically record and bill postage to various departments based on identifying information entered by the operator at the beginning of each mailing run. The charge meter may employ a display/receipt printer that provides the user with a visual indication of the value of the charge and/or receipt of postage payment. The rate meter may also use user-supplied equipment, such as a computer terminal or minicomputer system, for data collection in real time, such as in parcel processing where postage is added to the addressee's bill. . The ease of interfacing to fare meters of the present invention suggests yet another possibility. Two examples (1)
(2) Use at the end of a determining inserter to change the postage rate with a varying number of inserts; (2) Use as an actual mailmat. Flowcharts representing the operating sequences of the various units are shown in FIGS. 14, 15 and 16. In each case, figures without text are those in which the corresponding figure number and letter are combined to represent the entire flowchart. A flowchart representing the operation of the control unit is shown in the sequence of FIG. A flowchart representing the operation of the printing unit is shown in the sequence of FIG. A flowchart representing the operation of the accounting unit is shown in the sequence of FIG. Terms as used herein, postage meter and postal meter
means the general definition of a device for printing fixed unit values for government or personal mail parcel, envelope or package delivery, or other similar uses for printing unit values. is known and understood. As such, the term postage meter was used, but both are known in the trade as a general term for devices used in connection with services other than those used exclusively by government postal services. It is also used. For example, personal package or freight forwarding services purchase and use postage meters as a means of providing unit value pricing for individual packages, including accounting and printing functions. The present invention is intended for use in postage meters employing the varying features and functions described with respect to different aspects in one or more of the following groups of pending patent applications, all filed concurrently, including this application: ing. No. 089424 to Jones et al.
METER HAVING INTERACTIVE
ARITHMETIC OPERATION
CAPABILITY), the invention of U.S. Patent Application No. 089425 to Eckert et al.
METER HAVING FIELD RESETTABLE
089426 to Eckert et al.
HAVING KEYBOARD ENTERED
COMBINATION FOR RECHARGING)”
ELECTRONIC POSTAGE METER WITH CHECK DATE WARNING
HAVING CHECK DATE WARNING)”,
ELECTRONIC POSTAGE METER WITH RESET-BASED ALERT
HAVING RESET BASEWARNING)”,
No. 089434 to Muller et al. for the invention ELECTRONIC POSTAGE METER
OPERATING VOLTAGE VARIATION
"PRINT CONTROL SYSTEM", Invention of U.S. Patent Application No. 089412 to Eckert et al., "PRINT CONTROL SYSTEM", Soderberg
No. 089413 to et al. Invention ``Electronic Postage Meter with Multiple Computing Devices''
HAVING PLURAL COMPUTING
089411 to Eckert et al.
ELECTRNIC POSTGE METER). (d) Effects The present invention compares messages communicated between a control device and a unit inside a postage meter or an external device bit by bit. Therefore, it is possible to confirm whether a message has been correctly transmitted between a specific unit and a control device, and the safety of transmitted data is guaranteed. Since postage meter communications require strict data security, it is particularly important to detect errors in transmitted data as in the present invention.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a postage meter incorporated into the system of the present invention, FIG. 2 is an enlarged view of the panel of the postage meter of FIG. 1, and FIG. 3 shows the arrangement of elements according to an embodiment of the invention. 4 is a circuit diagram of a control unit for a postage meter according to the invention, FIG. 5 is a circuit diagram for an accounting device for a postage meter according to the invention, and FIG. 6 is a circuit diagram for a postage meter according to the invention. 7 is a circuit diagram of a photoelectric isolator used in the present invention. FIG. 8 is a detailed block diagram of an embodiment of an accounting unit of the present invention. FIG. 9 is a detailed block diagram of an embodiment of the accounting unit of the present invention. 1 is a block diagram of an embodiment of the electrical circuit of the printing unit of the postage meter of the invention; FIG. FIG. 10 is a timing diagram showing the re-communication operation of the present invention, FIG. 11 is a logic diagram showing transmission from the charge meter, FIG. 12 is a logic diagram showing transmission to the charge meter, and FIG. 13 is a logic diagram showing transmission from the charge meter. FIG. 14 is a diagram showing a plurality of external devices connected in a chain, and FIG. 14 is a diagram showing a continuous set of flowcharts showing the operation of the control unit, and FIGS. 14A to 14I are respectively set according to FIG. FIG. 15 is a diagram illustrating a successive set of flowcharts illustrating the operation of the printing unit; FIG.
15A to 15F each show a portion of a flowchart set according to FIG. 15 and showing the operation of the printing unit, and FIG. 16 shows a continuous set of flowcharts showing the operation of the accounting unit. 16A through 16L each show a portion of a flowchart set up in accordance with FIG. 16 and showing the operation of the printing unit. 20: Postage meter, 21: Base, 22: Slot, 23: Display panel, 24: Control panel, 25: Power cable, 28: Date printer door, 45: Switch.

Claims (1)

[Scope of Claims] 1. A postal service for printing postage in order to transmit binary data and control signals for postage to and from an electronic postage meter inside or outside the electronic postage meter. A control device for an electronic postage meter comprising a serial interface for an electronic postage meter including a printing unit and an accounting unit for accounting for printed postage, said control device 75 comprising a serial interface for an electronic postage meter, said control device 75 A signal transmitter is provided connected to the interface 81 for the transmission of data and control signals applied serially to the interface as information in the form of start bits and stop bits, the data format being divided word by word into a first logic a stop bit and a start bit having levels and a stop bit having a second logic level different from the first logic level at the end of each message; The data and control signals are compared bit by bit for identification with the data or control signals arriving at the interface from outside the control device, and if a match is found, the first logic level following the stop bit is set at the end of the message. and, if there is no match, an unconfirmed signal having said second logic level to said interface. 2. A control device according to claim 1, characterized in that the control signals from the signal transmitter effect a complete transfer of control of the postage meter to the control device. 3. The control signal from the signal transmitter includes a transfer control instruction, and the transfer control instruction causes the contents of the register of the accounting unit of the postage meter to be transferred directly to the control device.
The control device according to item or item 2. 4. The control signal from the signal transmitter includes a transfer control command, and the transfer control command causes the contents of the display device of the postage meter to be directly transferred to the control device. The control device according to any one of paragraphs. 5. The control signal from the signal transmitter includes a control command, and the control command prevents the input of a data signal from outside the postage control device to the postage meter. A control device according to any one of items 1 to 4.