JPS61174978A - Method and device for executing diagnostic test in mail machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to mail machines and, more particularly, to a method and method for using a control keyboard to perform diagnostic tests on mail machine subsystems without the use of special equipment. Apparatus, as well as methods and apparatus for diagnostic testing the contents of programmable devices within mailing machines.

Mechanical mail machines with automatic letter feeders and postage needle feet and printing devices are widely used. These conventional machines use primarily mechanical means of controlling the document feed to print the metered postage indicia in the correct location on the document. This requires mechanical control means to supply documents of variable length and thickness and to perform and maintain registration of the printed indicia for each document. Such mechanical control mechanisms are often unreliable, require frequent maintenance, are largely non-programmable, and require periodic adjustments and component replacement due to aging and fatigue of the mechanical components. shall be.

Most of the problems with these conventional devices can be avoided by using digital electronic controllers that increase reliability and have programmability using programmable elements.

This programmable device allows for easy updates of system software and flexibility to compensate for fatigue of mechanical elements, while creating a need for a simple diagnostic test system. In the prior art, this test required special equipment used by technicians.

Accordingly, it is an object of the present invention to provide an improved system for diagnostic checking of mail machine subsystems.

Another object of the invention is to use a keyboard and display of a control panel of a mailing machine to operate and monitor the subsystems of the mailing machine to enable testing without the use of external equipment. An object of the present invention is to provide an improved diagnostic check system for.

Another object of the present invention is to provide an improved system for diagnostically checking the proper functioning of programmable devices within mailing machines.

Another object of the present invention is to provide an improved diagnostic check system for programmable devices in mail machines that is easy to use and can operate in real time without the need for special equipment.

In summary, in accordance with one embodiment of the present invention, a diagnostic test apparatus for a subsystem of an automated mail machine is provided. The apparatus includes a control panel means having a plurality of control keys and a visual display, and a control panel means for controlling operation of the mailing machine in a normal mode of operation, and responsive to activation of at least one selected key of the control panel means. and means for starting the test mode. Additionally, means are provided for performing a selected one of the plurality of diagnostic tests in response to initiation of the test mode. According to another embodiment of the present invention, an apparatus is provided for diagnostic testing the contents of programmable devices within automated mail machines. The diagnostic test apparatus includes a control panel means having a plurality of control switches and a visual display for controlling the functions of the mailing machine in a normal mode of operation and a test mode responsive to activation of selected keys of the control panel means. and a means for starting the process. Additionally, means are provided for modifying the contents of the programmable device to obtain a summation value in response to initiation of the test mode. The total sum value is also displayed on the visual display, or alternatively, means are provided for comparing the total sum value to a preselected check sum value and displaying an error indication in response to the difference.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram illustrating an embodiment of a mailing machine 10 employing the present invention. Postal machine 10 includes various subsystems described below, including a document feeder bin 12 that holds documents to an automatic document feeder 13. Document supply bag @13 feeds a conventional belt and roller document transport mechanism (not shown) contained within housing 14. The document feeding device 13 and the transport mechanism are also located in the housing 10
It is driven in the conventional manner by a drive motor (not shown) contained within. Adjustment knob 16 allows adjustment of feeding device 13 to provide a range of envelope thicknesses. The transport mechanism uses a transport belt (not shown) to move each document along the document deck 18 to the postage meter 20.

The postage meter 20, when energized, prints a postage stamp on the document and seals the envelope of the document. A control panel 22 with control keys and a visual display provides operator control of the functions of the mailing machine, and a meter selection lever 24 can disable the meter to only seal envelopes without printing postage indicia; Furthermore, the charge meter can be removed from the mail machine. In the preferred embodiment, the postage meter is mechanical, but it may also be electronic or partially electronic. Photo sensor placed inside the housing! ±
(not shown) is used to detect the flow of documents through the transport mechanism.

In FIG. 2, a mail machine control panel 22 is shown which provides operator control of the functions of the mail machine. The control panel 22 includes a test mode key 102 for activating a test mode, an ink key 104 for activating an ink solenoid that supplies ink to the postage printing mechanism, a start key 106 for starting the mail machine, and a start key 106 for stopping the mail machine. A stop key 108 and a clear key 110 for clearing a display 112 are provided. Display 11
2 is preferably a 4-digit emitting diode (LED) display that displays the number of pieces and diagnostic information.

The test, ink, and start keys each include an indicator light (e.g., an LED in the preferred embodiment), indicated by reference numerals 114, 116, and 118, to inform the operator when the associated key is energized. A jam indicator 120 lets you know when a document is jammed in the machine, and a power-on indicator 122
signals when power is applied to the mailing machine. Furthermore,
A bank of switches located below the control panel allows adjustment of the printing position of the postage indicia printed by the postage meter.

The mail machine control panel 22 provides operator control of the mail machine's functions in a normal operating mode and provides control of diagnostic test procedures in a test mode (i.e., the control panel keys do not contain code entry keys to initiate tests). It performs the dual function of (acting as) The test key is pressed when the operator desires to test the mail machine, thereby switching the machine to test mode. In test mode, the operator enters a password sequence (e.g., pressing the Ink, Stop, Clear, and Ink keys in sequence) using the keys on the control panel;
This starts the test procedure. After entering the correct password, the display will display sign-on (5i(l)
n-On) message (eg, HELP in the preferred embodiment) after which the operator can enter a test code using various keys on the control panel to begin the test.

This procedure allows the operator to start and monitor the mail machine's electrical or electromechanical devices via a control panel using an LED display for information output. To stop a test in progress, the stop key is pressed. The Stop key interrupts the test being performed and displays [ENOOJ on the visual display. This indicates that the system is ready to start another diagnostic test. To exit diagnostic test mode, the test key is pressed. This test key disables the test indicator light and switches the system to the normal mode of operation.

FIG. 3 shows a control circuit 200 for a mailing machine according to the present invention.
A detailed block diagram of an embodiment is shown.

Microcomputer 202 (for example, Intel 8
031) provides central processing power to the system with an internal oscillator regulated by a crystal and capacitor circuit 201 and a power-up reset provided by capacitor '1J203. An electrically programmed read-only memory (EPItOH) 204 is shown as
Addressed by microcomputer 202 via an 8-bit address connected to 8-bit branch 210 through bus 208 and a 4-bit bus 206 from the upper byte of the address port of microcomputer 202. EPROH 204 is enabled by the program storage enable signal (PSEN) and latch 210 is enabled by the address latch enable strobe (ALE).
) is strobed.

Addressed data from EPRO)l 204 is connected to data bus 214 when strobed by the PSEN signal. Bidirectional bus transceiver 212
provides a buffer for passing data between bus 208 and data bus 214, as shown, and provides a buffer for passing data between the PSEN signal and the read signal from microcomputer 202 (
RD). Chip enablement decoder 2
18 is provided for generating enable signals to control several peripheral latches 228, 232 and buffer circuit 226, and as shown, four secondary side addresses coupled from latch 210. line and is controlled by the microcomputer 202 via the RO double signal and write strobe (14R). periodically (e.g., every 150 m5 in the preferred embodiment) by the microcomputer 202 via the data line 221.
A conventional retriggered lookout timer 220 (eg, a monostable multivibrator) is provided to generate the lookout signal. This signal is connected to the microcomputer external interrupt zero input (INTO) along with several latch circuits 228, 232 as shown. Thus, if the microcomputer 202 is stopped or turned off, the watchdog timer interrupts the processor and disables the display and power latches 228, 232 to allow restart.

A letter sensor 222 (eg, a photo sensor) is provided to detect document flow through the mailing machine by generating an interrupt signal in response to detection of the leading edge of the document. This interrupt signal is sent to buffer 2 as shown in the figure.
34 is connected to the microcomputer external interrupt power.

In response to this interrupt, the microcomputer 202
is a constant delay time (e.g., 40n+s in the preferred embodiment)
). During this time, microcomputer 2
02 reads data from a bank of data switches 216 that determine the programmable delay. This delay is added to the constant delay and after the total delay period microcomputer 202 energizes a letter solenoid (not shown). The letter solenoid energizes the postage meter 20 to cause a postage indicia to be printed. The photosensor signal from the trailing edge of the document is used by microcomputer 202 to prepare the next leading edge. If no trailing edge occurs during 40011S, the processor generates a "jam J" signal which energizes the jam indicator 120, which controls the letter solenoid.

The ink solenoid supplies ink to the postage meter for 10 seconds in response to activation of the ink key 104. The signals controlling these solenoids are connected from microcomputer 202 through data bus 214 to latch 228 and then through power buffer 230 as shown. Additionally, some of the data connected to the latch 228 is used to control a motor (not shown) that drives the document feeder and transport mechanism.

Switch bank 216 includes a set of four switches (e.g.
The preferred embodiment includes a DIP switch package. This set of switches is connected to the buffer 22 as shown.
6 to the data bus 214, which allows the 2
The hex-encoded switch data is provided to microcomputer 202 via bus 214 and bus transceiver 212. This data is used by microcomputer 202 to determine the magnitude of the time delay between detection of the leading edge of a document through the mailing machine's transport mechanism and printing of postage indicia on the document. These selection switches thus allow the operator to control the positioning of the indicia according to adjusting the delay. There are four switches configured for binary encoding, so a total of 16 delay values can be selected, each corresponding to approximately 1/8 of an inch shift in the position of the printed indicia (i.e., 2.5i
si extension). Additionally, a single line from the fifth switch in switch bank 216 is connected to the EA input of microcomputer 202, giving the choice of using either internal or external ROM.

The microcomputer 202 has two paths, as shown: (1) a 6-bit data bus 236 and (2) a 6-bit data bus 236;
It communicates with control panel 22 via a path through latch 232 and buffer 234 . Data bus 236 is connected to a 3x3 keyboard matrix and provides input to microcomputer 202 from a total of nine switches. As previously mentioned, only five of these switches are currently in use. Furthermore, the 4-bit data is transmitted through a test indicator light 116, a start indicator light 118,
and jam 70 - connected from bus 214 via latch 232 and buffer 234 to energize indicator light 120 . Finally, the data DDATA on line 240 for display on D display 112 is serially clocked into a set of display registers in the display by a signal DCL on line 238. .

FIG. 4 is a flowchart of a diagnostic test start sequence according to the present invention. The test start sequence is
It begins with the software running in normal mode as shown at 300 . At block 310, a test is performed to determine whether the test key was pressed. If not pressed, the system returns to normal mode and continues in normal mode. If the test key is pressed, the system has a password entered and then a logic test is performed as shown at 320 to determine if a valid password was entered. If a valid password was not entered, the system returns to the normal mode of operation as shown.

If a valid password is entered, a sign-on message is displayed on the LED display 45 on the control panel as shown at block 330. The system then waits for the test selection code to be entered, after which a "legal code" logic test is performed to determine whether the correct test code was entered as illustrated at 340. If the proper test code is not entered, program control passes to block 350 to determine whether a test key has been pressed, which exits test mode and returns to normal mode. If the test key was not pressed, the system then returns to block 340 and continues to monitor valid test code. If a valid test code is entered, the system proceeds to run the test according to the entered test code as shown at block 360, and the test proceeds to run the test according to the entered test code as shown at block 370. 58-5F are flowcharts of some suitable tests) Monitoring the stop key to determine if it should be stopped. If the test is to be stopped at block 370, the system returns control to block 360 as shown. If the stop button is pressed, the test is stopped and the display shows a stopped test indicator (e.g., rENOOJ in the preferred embodiment) as shown in block 380.
. Program control then passes to block 340 which allows exiting the test mode by pressing a test key or allowing another test to be performed by entering a valid test code.

There are numerous tests that can be performed by the disclosed system. However, in the preferred embodiment, six tests were performed. Testing of the LED display and LED indicator lights is initiated by pressing the ink key twice and then the start key (i.e., the test code for display testing in the preferred embodiment). This is 000
Initialize all segments of the LED display with a count of 0 and turn on all LIED indicators simultaneously (see Figure 5A). The test then proceeds by turning off each ED in turn and incrementing all four digits on the display until each LED is turned off and the display reads 4444. L
ED is then turned back on and the display is incremented,
The procedure is repeated until the display reads 9999. This entire procedure continues to repeat until the stop key is pressed.

The optical sensor test is initiated by first lifting the document carrying belt to access the photosensor (see Figure 5B) and then pressing the ink, stop and start keys. The operator can then test the sensor by alternately inserting a document to block the sensor causing it to display 0000 and removing a document from the document deck causing it to display 1111. The stop key is pressed to end the test.

The check sum test is initiated by pressing the start key twice followed by the stop key to begin the test. This is the Su displayed in the two most significant digit positions.
Display the sum of the contents of PROH in hexadecimal format as the two least significant digits of a display with . 5th C
The figure shows a flowchart of a program for performing a checksum test. This program is executed at block 360 in FIG. The program is entered at block 400 from the point following block 340 in FIG. 4 if a valid test code is entered. At block 400, the accumulator labeled SUN is set to zero and the address pointer is set to zero. Program flow then proceeds to block 410 where the data bit at the address of the address pointer is fetched from memory and this data bit is then added to the value of accumulator 5O)4 as shown at 420. Give a new value of SuH. After the new 811M value is calculated, the program flow continues in block 4.
Proceeding to 30, the address pointer is tested as shown at 440 to determine if the most significant bit is equal to one.

If the most significant bit is not equal to 1, indicating that all memory was not added, program flow returns to block 410, where the process repeats. However, if the most significant bit of the address pointer is equal to 1, indicating that the addition process is complete, program flow continues to block 450 where SU
The N sum is formed for display on the LED display 112.

The sum is then displayed as a hexadecimal value on the LED display, as shown at 460, and program control then passes to block 370, as shown in FIG.

In another method, the expected value of 5tlH is stored in memory and the calculated SUN is compared to the expected value. If a difference exists, an error message is displayed, and if no difference is found, a message indicating the correct 811)1 is displayed.

The motor on test is initiated by pressing the ink, clear and start keys to initiate the test which drives the motor until the stop key is pressed (see Figure 5D). To perform the letter solenoid on/off test, first move the meter selection lever from the operating position to the sealing only position (i.e.
Disable the charge meter), then clear,
Started by pressing the ink and start keys (
(See Figure 5E). The letter solenoid is energized and deenergized every second verifying solenoid operation. The data switch position test is initiated by pressing the Clear, Stop and Start keys. The display then reads rPO3=J (meaning r position equals J)
, followed by displaying the switch position data value in hexadecimal format (Figure 5F). Each test can be stopped by pressing the stop key.

[Brief explanation of drawings]

1 is a diagram showing an embodiment of the mail machine of the present invention, FIG. 2 is a diagram showing an embodiment of the control panel of the mail machine shown in FIG. 1, and FIG. 3 is a diagram showing an embodiment of the mail machine electronics of the present invention. 4 is a detailed block diagram of an embodiment of the control circuit, FIG. 4 is a 70-step diagram of the diagnostic test start sequence of the present invention, FIG. 5A is a flowchart of the display diagnostic test program, and FIG. 5B is a diagram of the photosensor diagnostic test program. Flowchart, 5th
FIG. 5F is a flowchart of the data switch position test program. DESCRIPTION OF SYMBOLS 10... Postal machine 12... Document supply position bin 13... Document supply device 14... Housing 16... Adjustment knob 18... Document deck 20... Postage meter 22... Control Panel 2
4...Toll meter selection lever (5 other people) d:==LE'-

Claims (46)

[Claims] (1) In a method of performing diagnostic tests on an automatic mailing machine comprising a plurality of subsystems and a control panel having a visible display and a plurality of keys for controlling operation of the mailing machine during a normal mode of operation. , initiating a test mode in response to activating a predetermined key on the control panel, and performing a selected one of a plurality of diagnostic tests in response to initiating the test mode. A method of performing a diagnostic test on an automated mail machine, comprising steps. (2) The method of claim 1, comprising the step of converting a control panel to function as a test selection panel in response to initiating a test mode. (3) As defined in claim 2, further comprising the step of generating a password signal in response to activating a predetermined sequence of control panel keys, wherein the selected diagnostic test is in a test mode. A method executed in response to the occurrence of an initiation and password signal. (4) As defined in claim 3, further comprising the step of generating a test code signal in response to activating a predetermined sequence of keys on a control panel, the selected diagnostic test comprising: A method that is executed only in response to the initiation of a test mode and the generation of a password signal and a test code signal. (5) In claim 3, one of the plurality of diagnostic tests includes activating a predetermined subsystem of the mailing machine and deactivating the subsystem in response to activation of a stop key. and displaying an end of test instructions on a visual display in response to activation of a stop key. (6) In claim 3, one of the plurality of diagnostic tests includes initializing a visual display with a predetermined set of characters, and testing the visual display with a predetermined sequence of characters. and repeating this sequence until activation of a stop key. (7) In claim 3, the mailing machine includes a photosensor and one of the plurality of diagnostic tests:
displaying a predetermined set of characters on the visible display in response to blocking the photosensor; displaying a second set of characters on the visible display in response to clearing the photosensor;
displaying a predetermined set of characters, and stopping the test in response to activation of a stop key. (8) In claim 3, a mailing machine includes a postage meter energized by a letter solenoid, and one of the plurality of diagnostic tests includes stretching the solenoid for a predetermined period of time, A method comprising the steps of contracting a solenoid for a period of time and repeating the extension and contraction until a stop key is pressed. (9) The method of claim 8, including the step of disabling the postage meter prior to energizing the letter solenoid test. (10) A diagnostic test device for a subsystem of an automatic mailing machine, comprising: control panel means having a plurality of control keys and a visual display for controlling operation of the mailing machine during a normal mode of operation; means for initiating a test mode in response to activating at least one selected key of the means; and means for performing a selected one of the plurality of diagnostic tests in response to initiating the test mode; A diagnostic test device for a subsystem of an automatic mail machine, characterized in that it comprises: (11) The apparatus of claim 10, comprising means for selecting one of a plurality of tests in response to activation of a test code sequence of a key on a control panel means specific to the selected test. . 12. The apparatus of claim 11, comprising means for inhibiting use of the execution means and the selection means in the absence of activation of a predetermined password sequence of control panel keys. (13) In claim 10, converting means for converting control keys of a control panel into code input keys in response to initiation of a test mode; and code input for detecting activation of a predetermined password sequence. means for monitoring the key and disabling the means for performing selected tests in the absence of detection of a password sequence. (14) The apparatus of claim 13, comprising means for returning to a normal mode of operation in response to detection of an incorrect password sequence. (15) As defined in claim 11, the means for executing, in response to a unique test code sequence,
Apparatus having means for energizing certain subsystems of a mailing machine and for deenergizing the subsystems in response to activation of a stop key. (16) As defined in claim 11, the means for performing initializes the visual display with a predetermined set of characters and increments the visual display with a predetermined sequence of characters in response to a unique test code sequence. A device having means. (17) The mailing machine includes a photosensor, and the means for executing, in response to a unique test code sequence, displays a predetermined set of images on a visual display in response to blocking of the photosensor. and means for displaying a second predetermined set of characters on the visual display in response to clearing of the photosensor. (18) In claim 11, the mailing machine is equipped with a letter solenoid, and the means for performing:
Apparatus having means for deflating a solenoid for a predetermined period of time in response to a unique test code sequence. (19) A mailing machine for use with a postage meter having multiple subsystems, the document holding means for holding a plurality of documents to be processed by the mailing machine, and a document supply for supplying each document from the document holding means to the mailing machine. means for transporting each document from the document supply means to the postage meter; control panel means having a plurality of control keys and a visual display for allowing operator control of the operation of the mailing machine in a normal mode of operation; means for initiating a test mode in response to activation of at least one selected key of the control panel means; and means for performing a selected one of a plurality of diagnostic tests in response to initiating the test mode; A postal machine comprising: (20) Claim 19, further comprising converting means for converting control keys of a control panel into code input keys in response to initiation of a test mode, and code input for detecting activation of a predetermined password sequence. A postal machine having means for monitoring keys and disabling the execution means if a password sequence is not detected. (21) In claim 20, means for monitoring the code input key to detect activation of a predetermined test code sequence of the code input key, and prohibiting the use of the execution means if the test code sequence is not detected. postal machine having means for (22) A mailing machine as claimed in claim 20, having means for returning to a normal mode of operation in response to detection of an incorrect password sequence. 23. The postage meter of claim 21, wherein the postage meter is a removable mechanical meter energized by a letter solenoid, and the means for executing, in response to a unique test code sequence, A mailing machine having means for extending a solenoid for a predetermined period of time and retracting the solenoid for a predetermined period of time. (24) In claim 21, the means for executing, in response to a unique test code sequence,
A mailing machine having means for energizing certain subsystems of the mailing machine and for deenergizing the subsystems in response to activation of a stop key. (25) As defined in claim 21, the means for executing, in response to a unique test code sequence,
A mailing machine having means for initializing a visual display with a predetermined set of characters and incrementing the visual display by a predetermined sequence of characters. (26) The mailing machine includes a photosensor, and the means for executing, in response to a unique test code sequence, determines a predetermined set of characters in response to blocking of the photosensor. A mailing machine having means for displaying on a visual display and responsive to clearing of a photosensor for displaying a second predetermined set of characters on the visual display. (27) performing diagnostic tests on the contents of a programmable device within an automatic mailing machine having a control panel having a visible display and a plurality of keys, including a test key, for controlling functions of the mailing machine during a normal mode of operation; A method comprising: switching to a test mode in response to activation of a test key on a control panel; summing the contents of a programmable device to obtain a summation value in response to switching to the test mode;
and displaying the sum value on a control panel display. (28) The method of claim 27, including the step of converting the control panel to function as a test selection panel in response to switching to test mode. (29) Claim 28, further comprising the step of generating a password signal in response to activation of a predetermined sequence of keys on a control panel, wherein the adding step includes switching to a test mode and A method comprising the step of summing the contents of a programmable device only in response to the occurrence of a password signal. (30) Claim 29, further comprising the step of generating a test code signal in response to activation of a predetermined sequence of keys on a control panel, wherein the step of summing includes the step of: and a password signal. 31. The method of claim 27, comprising the steps of comparing the total sum value to a predetermined check value and generating an error signal in response to the difference. (32) Claim 27, comprising the steps of maintaining the summation value on the control panel display until actuation of the stop key and clearing the display in response to actuation of the stop key. Method. (33) An apparatus for diagnostic testing of the contents of programmable devices within an automatic mailing machine, the control panel having a plurality of control keys and a visual display for controlling the functions of the mailing machine in a normal mode of operation; means for initiating a test mode in response to activation of a selected key of the means; and means for summing the contents of the programmable device to obtain a summation value in response to initiating the test mode. Equipment for diagnostic testing of the contents of programmable devices within machines. (34) An apparatus according to claim 33, comprising means for displaying the sum value on a visual display. (35) Claim 34, further comprising converting means for converting a control key into a code entry key in response to initiation of a test mode, and monitoring the code entry key to detect activation of a predetermined password sequence. and having means for inhibiting addition if a password sequence is not detected. (36) In claim 35, means for monitoring a code input key to detect activation of a predetermined test code sequence on the code input key, and prohibiting addition if no test code sequence is detected. A device having means. (37) In claim 33, means for storing a preselected sum value, means for comparing a total sum value with a preselected sum value, and a preselected sum value. device having means for displaying an error indication on a visual display in response to the difference between the sum value and the sum value. 38. The apparatus of claim 35, having means for returning to a normal mode of operation in response to detection of an incorrect password sequence. (39) In claim 35, means for storing a preselected sum value, means for comparing a total sum value with a preselected sum value, and a preselected sum value. and means for displaying an error indication on a visual display in response to the difference between the sum value and the sum value. (40) The apparatus according to claim 34, wherein the programmable device is a ROM. (41) A mailing machine for use with a postage meter having a programmable device, comprising: document holding means for holding a plurality of documents for processing by the mailing machine; and a document supply supplying each document from the document holding means to the mailing machine. means for transporting each document from the document supply means to the postage meter; a control panel having a plurality of control keys and a visible display and allowing operator control of the functions of the mailing machine in a normal mode of operation; means for initiating a test mode in response to activation of a selected key of the control panel means; and means for summing the contents of the programmable device to obtain a summation value in response to initiating the test mode; A postal machine comprising: (42) A mailing machine according to claim 41, having means for displaying the sum value on a visual display. (43) Claim 41, further comprising converting means for converting control keys of a control panel into code entry keys in response to initiation of a test mode, and code entry for detecting activation of a predetermined password sequence. Postal machine having means for monitoring keys and inhibiting addition if a password sequence is not detected. (44) In claim 43, means for monitoring a code input key to detect activation of a predetermined test code sequence on the code input key, and prohibiting addition if no test code sequence is detected. Postal machine with means. (45) In claim 41, means for storing a preselected sum value, means for comparing the total sum value with a preselected sum value, and a preselected sum value. A mailing machine having means for displaying an error indication on a visual display in response to a difference between the sum values. 46. The mailing machine of claim 43, having means for returning to a normal mode of operation in response to detection of an incorrect password sequence.