Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to electronic postage meters,
and is more particularly directed to an electronic postage
meter of the type havin~ a keyboard for the entry of postage
to be printed, a display for displaying postage to be
printed as well as other data, an electronic accounting
device, and a printing mechanism.
Devices of the above type are generally known, and
are discussed, for e~ample, in U.S. Patent No. 3,978,457
wherein is disclosed a system for a postal meter including a
keyboard for the manual introductioll of data corresponding
to the postage to be printed4
In electronic postage meters of one type, for
example, as disclosed in the above noted U.S. patent,
recharging of the postal meter generally requires the opening
of a sealed access door to control a switch, if the meter is
to be recharged at a post office.
- With this type of a meter, the only security offered,
from the standpoint of recharging of the meter, is the seal.
Since this sole security measure may be subject to
tampering, it is therefore desirable io provide additional
protection means for maintaining the integrity of the system.
Therefore, in accordance with the present invention, means
are provided for improving the security of electronic postage
meter systems, wherein the seal of a recharging switch does
not constitute the only effective measure preventing access
to the funding register to effect the meter recharging.
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~riefly stated, in accordance with the invention, a
register is provided within the electronic postage meter for
the storage of a fixed combination. This ragister may form
. a part of the central processing unit, or it may be in separate
memory. The meter is further provided with means responsive
to the entry of a combinational set from the keyboard, consist-
ing of a combination and-a value for recharging the postage
meter, the entered combination is compared with the stored
combination in order to inhibit the recharging of the meter
under control of the sealed switch, unless a successful com-
parison is obtained. As a.consequence, a central authority such
as the post office is readily enabled to recharge the meter, .~.
employing the sealed switch in conjunction with the combina-
tional set, the fixed combination being unknown to other persons.
Meters of this.type are further provided with error detecting
routlnes, so that the tampering with the machine is efective
in blocking reception by the ~.eter of further recharging
attempts if wrong combinational sets are entered a determined
number of times.
In order that the invention will be more clearly
understood, it will now be disclosed in gxeater detail with
reference to the accompanylng drawings, wherein: ~ :
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Fig. 1 is a simplified perspective v:iew of a postal
m~ter which may inco~porate the-system of the present invention;
Fig. 2 is an enlarged view of the panel of the postal
meter o~ Fig. l;
Fig. 3 is a simplified block diagram of the orientation
of the elements in accordance with a preferred embodim~nt of
the invention;
Fig. 4 is a simplified diagram of the circuitry of
a control unit for a postal meter in accordance with the
invention;
Fig. 5 is a simplified diagram of a circuit for the
accounting system of a postal meter in accordance with the
invention;
Fig. 6 ls a more detailed block diagram of a
preferred embodiment of the control unit for a postal meter
in accordance with the invention;
Fig. 7 is a circuit diagram of an opto-electric
isolator that may be employed in the present invention;
Pig. B is a more detailed block diagram o~ a
preferred embodiment of an accounting unit in accordance with
the invention; and
Fig. 9 is a block diagram of a preferred embodiment
of the electrical system of the printing unit of a postal
meter in accordance with the invention.
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Referring now to the drawings, and more in particular
to Fig. 1, therein is illustrated a postage meter 20 removably
affixed to a base ~1, in accordance with one embodiment of the
invention. In this arrangement, a slot 22 is provided between
the postage meter 20 and the base 21 at the forward edge thereof,
for receiving envelopes or the like and the printing of postage
thereon. The postage meter is provided with a display panel 23,
preferably an electronic display device, as well as a control
panel 24 which may be organized in a manner to be disciosed in
the following paragraphs. The apparatus may be energized by way
of a supply cable 25.
The postage-meter 20 illustrated in Fig. 1 may be of
the type that is removable from the base 21, and the base 21
may be of the type disclosed, for example, in U.S. Patent
No. 2,934,009, Bach, et al, incorporating a mechanical drive
for operation of the printing mechanism in the meter 20. The
separability of the meter and base renders the electronic meter
compatible with conventional driving units, simplifies servicing
of the device and, i~ ne~essary, simpli~ies transport of the
meter for recharging if remo~e charging capabilities are not
employed.
The panel for the postage meter i5 more clearly illus-
trated in Fig. 2, wherein it is seen that the meter is provided
with a numeric display 30, for example, a conventional
multiplexed seven-segm~nt LED or LCD display. In addition, the
keyboard is provided with numeric setting keys 31 and a decimal
key 32 operative therewith, for setting the meter to print a
desired amount of postage, the amount normally being displayed
. on the display 30. A clear key 33 may also be provided to
clear the display amount in the event, for example, of an ~
erroneous entry. When the displayed amount has been set to - ~ ,
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the desired value, depression of a set postage key 34 effects
setting of the print wheels for setting postage.
The panel may further be provided with a series of
keys enabling the 3elective display of other values on the
S display 30. For example, depressi~n of a key 35 may enable
the display of the contents of an ascendinq register, i.e., the
postage used by the meter, and depression of a key 36 may enable
display of the contents of a descending register in the meter,
i.e., the postage for which the meter is still charged. Further
keys 37-40 may enable display in conventional manner of other
specific specialized values as control or postage sum, piece
count, batch value, and batch count, respectively. The batci~
value and batch count registers can be cleared by simultaneous
depression of either batch value key or batch count key and
the clear key C. The panel additionally preferably is provided
with an LED 41 which will be lit upon each application of
power to the meter, as is conventionally done at the beginning
of a day, to indicate that the dater has not been set or that
the dater door is open. A further LED aisplay 42 may be
provided and interconnected to be lit if necessary to reset the
trip mechanism in the base before operation is to continue.
In order to provide recharging of the meter, for example,
by way of the keyboard, the meter may be provided with a key ~ -
slot 45 illustrated in Fig. 1, in which the key 46 of Fig. 2
may be inserted. The shaft of the lock may be visible through
a window 47 to display the position of the key. Thus, in the
- normal setting of the key this shaft may display the message
~operate" as illustrated. This arrangement may also be employed
for remote meter resetting, as discussed, for example, in U.S.
Patent No. 4,097,9:23.
As a further feature, the meter may be prov~ded with
a service switch 50 at the rear thereof Çor the convenience o~
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field service personnel enabling use of the Iceys of the meter
for different functions. Vpon operation of the switch 50,
the keys 35 through 40 may thereby enable the dl6play of
additional values such as the unlock value, the low postage
warning amount, the meter number~ di~gnostic status, and the
maximum settable amount. Turning the swItch to an "enter
combination" position, as indicated in the window 47, while
entering a correct coded combination in the keyhoard, enables
the recharging mode of the meter to he effective. In the
charging mode, which may be attained by means of an internal
switch lock controlled by the key 46, an "enter amount" position
as shown by this message at the window 47, may enable entry of
recharging value registers of the meter by way of the keyboard.
Returning the key to the operate position enables the resumption
of the use of the meter for printing postage.
The service switch may be in an unsecured position in
the meter, since the display of the additional values rendered
possible by the use of this switch does no~ affect the security
of the meter, and merely enables the display of further values.
The fact that it is these values that are being displayed may
be shown by distinctive underlining of the display, if desired,
and the operation of the service switch 50 partially disables
the set postage key 34. It will then not be possible to set a
new value of postage in the postage meter when it is in the
~service~ mode and the interposer will act to block operation
of the meter in the service ~ode. However, the set key may
still be used to cause the display of the currently set value.
When the meter ~s in the service mode, i.e., with the
switch 50 operated, ~nd the switch 45 and key 46 acti~ated,
the entry into the keyboard o a new value and a code indicating
the function of that vaIue, will enable the resetting of the
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unlock value, low warning postage amount or maximum ~ettable
amount, resp~ctively. The "unlock" value i~ a determined
value, for example, one dollar, includlng and above which the
operator should be careful in setting 80 as to avo~d accidental
S printing of excessive amounts. For this purpose, all value~
including and above the unlock value require an additional step
on the part of the operator, such as an aaditional depression
of the set postage key 34. The display may be provided wlth a
distinctive indication, for example, one horizontal bar, to
indicate that the printing wheels have been set but the unlock
step, i.e., the additional depre~sion of the set postage key,
has not been effected. The completion of the unlock step would
be indicated by the display, for example, of three horizontal
bars to indicate that the meter is enabled to be tripped, to
print postage.
If the descending register does not contain sufficient
funds to cover the set amount on the print wheels, the entire
display may be caused to blink. On the other hand, if the
value stored in the descending register is ~ower than the low
postage warninq limit, the decimal point may be caused to blink.
The "maximum settable" amount, o~ course, cannot be exceeded in
the setting of any postage.
The meter may also pe provide~ with a "privileged"
switcb 51 that is normally held in the operate position by a
25 - seal. The operation of this switch, following the cutting of
the seal, enables the recharging of the meter by post office
personnel in ~ nonremote charging mode.
In addition, the meter is provided with one or more - -~
arithmetic function keys 52, enabling a variation of the
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postage setting amount, ~uch as the addition of further values
to the already displayed setting ~alue prior to the depression
of the set switch 34. This ~eat~re enables the introduction
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by the operator of further values; such as insurance or the
like, without the necessity for manual calculation or
c~lculation on a separate device.
~h~ internal components of the postage meter in
accordance with the invention are preferably oriented as
illustrated in Fig. 3, and include a first compartment 55
that is physically securej i.e., as secure as i3 reasonably
possible to avoid tampering with internal components thereof.
While it may not be possible to provide 100~ security in this
regard, physical evidence of tampering will be evident in any
event before entry can be gained. The compartment 55 encloses
the printing module 56, which may include a mechanical p~inting
assembly, and if desired, a separate microcomputer
for controlling this module.
The compartment 55 also encloses a further compartment
57, which is preferably electromagnetically shielded, and
encloses an accounting module 58. The accounting module is
connected to external devices, i.e., external of the compartment
57, only by optical or similar isolation couplers 59 as disclosed
in U.S. patent application Serial No.918,785 ~iled June 26, 1978,
in order to avoid damage thereto, either accidentai or intentional,
resulting from,introduction of noise, for example, excess ~oltages
into the accounting module. Such coupling is, of course, not
provided for the energy source thereof, which extends to a power
supply 60 in a separate compartment 61 also within the cecure
compartment 55. The power supply 60 is energized by way of a
filter 62 within the compartment 61, to insure the absence of
~ any voltage variations that would adversely affect the accounting
.. . module, the power input to the compartment ~1 being directed
lnto the compartment 55 fro~ a power supply system in a further
compartment 63 that i8 preferably defined by the outer secure
housing of the compartment 55. Thus, while it is not absolutely
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necessary for all the elements within the compartment 63 to
be physically secure, this feature is preferred.
~ The power from the mains plug 64 i8 fed into the
compartment 63, from where it may ble fed by way of a suitable
connection 65 ~o power the meter base. The power ~or the meter
may be fused in the compartment 63, by means of a fuse 66,
applied from the fuse to a thermostat 67 and thence to a
transient suppressor and filter 6B. The thermostat inhibits
application of voltage to the unit in the event of excess
temperatures. Further protection for the system is provided
by means of an isolation transformer 69 and an over voltage
cut-out device 70. The power for the meter is finally applied
to an energy storage device 71, such as a large valued capacitor
71, the capacitor 71 having adequate energy storage to enable
th~ self-protection features of the meter to operate, such as
to transfer data to a nonvolatile memory, in the event of a
power failure. The reduction of voltage may be sensed by a
sensor 72 in the secure housing 55, with one output of the
sensor being directed to the accounting module for signaling
the necessity of a mode change, and another output (which can
be mechanical) for inhibiting further printing module functions.
A furthe~ output of the isolation transformer 69 may
be fed exterDally o~ the meter to a control unit 75, and one of ~-
the isolated outputs of the accounting module may be directed
through the chamber 63 also to the control unit. The control -
uni~ 75 may thus constitute a keyboard control unit such as
~- illustrated in Fig. 2, including the key switches, displays,
- etc., necessary ~or local operation of the device. It is thus
. . apparent that the system of Fig. 3 orients the elements of the
- 30 postal meter so that elements which are less critical to the
security of the postal metee syst~m are provide~ with successively
lower levels o~ physical and electrical security.
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A pre~erred embodiment of a control unit 75 is illu~-
trated in Fig. 4 . This unit, f or versatility in d~sign, as
well a~ for minimi~ing the noncritical elements that must be
isolated in the physically secure hou3ing, preferably incorporates
a central processing unit 80, for e~ample, of the 6500 series, and
connected by way of conventional data lines, control lines and
address lines to a multipurpose con~rentional RAM/ROM I/O timer
circuit 81 incorporating read-only memories, random access
memories, timing control Plements and input/output interface
hardware. By the use o suitable decoders 82, the keyboard 83
may thereby be scanned in the conventional fashion, and by the
use of suitable drlvers 84 the visual display as may be energized,
preferably in a multiplexing mode according to conventional
practice. The data relating to the depression of any of -the keys
of the panel may thereby be communicated to the processing unit 80,
for the development of a serial input/output on the lines 86 for
communication with the accounting module 58 within the secure
housing 55. The processor 80 and circuit 81 are responsive to
~ the requirement for operator interventions to recock the trigger
mechanism in the base, and the failure to open or close the dater
door 28 (Fig. 1) followlng application of power to the unit,
to energize selectively àn indicator LED 87 corresponding to the
indicators 42 and 41, respectively, of Fig. 2. The service
switch 50 may also be connected to the circuit 81. If furthèr
- 25 input/output devices axe coupled to the control unit, such a~
external display device~ or control systems, these may be coupled
to the unit by way of further input~output lines 88, preferably~
serial communication paths which may be suitably isolated by
op~o isolator~, The unit may comprise an internal power supply ~ ;
3C and regulator 89 connected to rscelve power from the postage
metsr low voltage power as ~hown in Fig. 3.
The above-discus~ed functions under the control`of the
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control unlt are thus functions which are not cri~ioal in the
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sense that loss of control or the contents of any regi5ter
therein will not result in loss to the post office depa~tment,
or to the user, of funds. ~hese functions have been relegated
to the control unit in order that the secure portions of the
postal meter include only that programming of the system which
must be secure. Additional functions that may be effected by
the control unit, such as the addition of sequentially entered
amounts may also be controlled by tbe program of the control
unit, since such calculations are not critical to the security
of the apparatus, and need not be effected ~ithin the physically
secure portions of the postal meter. Similarly, the servicP
resettable functions may be effected by the programming in the
control unit, since these functions also are not critical to
the accounting system and registers themselves. ~owever, to
retain these parameters in nonvolatile memory, retention in the
accounting unit is desirable.
It will, of course, be apparent that, in a system such
as shown in Fig. 4, further arithmetic keys may be provided,
without great difficulty, such that the postage meter may be
2Q alternately employed also as a calculator.
Alternatively, the centra} processing unit and i~s
control circuit may be augmented by a calculator chip or the
,
like, connected to the keyboard and display for performing
arithmetic functions. ~ -
While the control unit of Fig. 4, including all of
the functions of the panel sh;own in Fig. 2 is preferably
disposed directly on the postage meter to form a part thereof,
it will be apparent that th~is portion of this system may be
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physically separate there~rom, or separable therefrom, whereby
the postage meter itself may incorporate only the elements that
are required to be physically secure~
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Since mon~tary information and control is prevalent
in the serial commUniCatiOn employed in the system, a high
degree of integrlty ~s mandatory. For this purpose, the system
i5 designed, in the serial trans~ission communication sections,
such that a transmittea bit is returned or "echoed" by the
receiver thereof for checking purposes. If the transmitter
thereby receives all of the echoed signals satisfactorily, it
may issue a "no error~ pulse, thereby informing the receiver of
the information that the reeeived information is valid.
The circuit arrangement of the acoounting compartment
is shown in somewhat greater detail in Fig. 5, wherein the
walls 90 of the compartment are illustrated as preferably
forming an electromagnetic shield. The circuits include an
accounting microcomputer 91 having a nonvolatile memory control
92 coupled thereto. The nonvolatile memory control controls the
applieation of stored data between a volatile memory, which may
form a part of the accounting mierocomputer 91 and a nonvolatile
memory 93. The volatile memories, such as random a~cess memories,
may funetion as working ascending registers, working descending
registers, and t~e like. The aceounting microcomputer also
includes read-only memory eontrol for the neeessary aeeounting
routines, as well as eontrol routines. Thi5 unit may, in
additionj ineorporate serial interfaces, to enable its interfaeing
with the printing and eontrol modules. The microcomputer may,
for example, comprise the 8048 series mierocomputer from Intel
Corporation, Santa Clara, Cali~ornia, with a eontrol eircuit in
a manner similar to that described above with respeet to the
control unit 75. In crder to avoid damage to the aecounting
module by eleetrie surges applied aeeidentally or intentionally,
and to eliminate electrical noise induced via groundloops, the
aeeounting mierocomputer eommunieates with the deviees ex~ernal
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of the compartment 57 by suitable isolators that are not
capable of applyin~ voltage sur~es to the microcomputer.
These isolators may, for cxample, be in the form of opto-
electronic couplers, and are also preferably arranged so as
to be inaccessible from the exterior of the postal meter.
One isolator unit 94 may be provided for the -two-way
communication path with the control uni-t. A further isolator
arrangement 95 may be provided for the two-way communication
with the printer unit, L.e., the printing module 56 of Fig. 3,
in particular, the microprocessor circuit thereof. A still
further isolator 96 may be provided for applying the power
sensing signals to the microcomputer 91. In addition, an
isolator 97 may be provided for controlling an interposer
(not shown) in the printing module, for example, for
mechanically blocking functions of the printer. Such a system
is disclosed, for example, in applicant's patent application
Serial No. 346,655 filed February 28, 1980.
The nonvolatile memory 93, at the present state
of the art, is preferably in the form of an MNOS memory,
which does not require a back-up power source. This memory
may, however, alternatively be formed of elements which do
require a power back-up, in which case a power control
circuit may be employed to apply back-up power thereto external
from the compartment 57. The purpose of the power control
circuit 98 is to provide power to the MNOS memory for the
purpose of effecting its data transfer operation, essentially
; during power up and power down. The program of the micro-
computing unit 91 is organized to enter the contents of
the registers of the computer units into the nonvolatile
memory as soon as any indlcation of failure of the power
supply occurs, and to restore this data to the working
registers upon restoration of the power.
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The thermost~t 67 in Fig. 3 cuts off power to the
meter in ~he event oE hi~h or low temperature operation.
This automatically places the meter in its power down cycle,
as a result of the power cut-off.
The compartment 57 may further comprise a temperature
sensor 99, with suitable circuits (no-t shown) coupled thereto,
such as to the microcomputer, for transferring data to the
nonvolatile memory in the event of excess temperatures. l'he
system may further be operative to prevent the operation of
the interposer solenoid by way of the isolator 97, in the
event of excess temperatures. It will be appreciated that
the interposer is controlled by the microcomputer 91 also to
inhibit operation of the printer in the event that insufficient
postage remains for a printing operation, or other accounting
data indicates that the unit should not be operative.
While the isolators have been indicated as individual
units, it is, of course, apparent that these units may
incorporate multiple devices, so that two-way communication
is established in the respective circuits. It is further
noted that systems for the transfer of data between volatile
and nonvolatile memories are well known, and are disclosed,
for example, in applicant's Canadian Patent No. 1,119,730,
issued March 9, 1982.
Referring now to Fig. 6, therein is illustrated in
greater detail a block diagram of a preferred embodiment of a ~ -
control unit in accordance with the invention. In this
figure the blocks have been identified by part numbers and
terminals where applicable. This unit is illustrated as
incorporating a type 6503 CPU 100 having its data and address
lines coupled to RAM/ROM I/O timer circuit 101 as well as to
a type 2716 PROM 102, the PROM 102 having stored therein the
program for the control unit. Control lines, such as
the interrupt line and read/write line may also be
connected to the circuit 101. The circuit 101
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has a plurality of port5, as will be discussed.
The control unit further incorporates the keyboard 103
including the numeric keys 31, the display keys 35-40, and the
three-position switch 45 shown in Fig. 1. This unit also includes
the add-through key 52 and the set postage key 34. All of these
keys and switches are connected in a matrix to the circuit 101,
in conventional manner, tb permit the scanning of the keys and
switches in accordanc~ ~ith the program, to detect a key or
switch closure. The eight-line port A, as well as four lines of
port B of the circuit 101, are also connec~ed to the seven-segment ~ -
display panel 104 for multiplexed display in the conventional
manner. The circuit 101 is further connected by a pair of serial
ports for communication to and from the accounting unit. In
addition, a pair of further serial ports enable communication to
and from external devices, by way of opto-electric isolators 107
- and 108, respectively. Another output port of the adaptor is
connected to LED 109 for indicating on the display panel that the
dater door has not been closed. A further output port is con-
nected to an LED 110 on the display panel for indicating that the
operator's intervention is required to recock the trigser mechanism
on the base. Finally, another port is coupled to the service
switch S0, to enable the functions of the postal meter in the
service mode.
In the preferred embodiment of the invention, the program
of the control~unit is directed to serviciny of the keyboard unit,
display panel, etc., so that the con~rol Punctions and storage of
data are effected primarily in the accounting unit. The program
thereby includes those functions necessary for the scanning of the
keyboard, multiplexing of ~ the display, formatting of signals for
communication wlth the other units, and with external devices,
etc., so that any new information may be passed on to the
accounting u~it.
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A typical opto-electric isolator is shown in Fig. 7,
this constituting primarily a conventional 6N136 device 115
including a solid st~te emitter for producing optical signals
for reception by a photodiode, the photodiode being connected
in the base circuit of a transistor amplifier.
A block diagram of a preferred example of the accounting
unit i5 illustrated in Fig. 8, wherein a type 8039 CPU 120 is
shown to communicate to the control unit by way of opto-electric
isolators 121 and 122, and to communicate serially with the
printer unit by way of opto-electric isolators 123 and 124. The
opto-electric isolators 121 and 122 within the accoLlnting unit
thus may be~ connected directly to the corresponding leads of the
control unit~ The isolators 123 and 124 may be connected directly
to the printer unit signal channels, since no further isolation
devices are necessa~y for this purpose. In addition, a control -
opto-electric isolator 125, for controlling an interposer or the
like in the printing unit may be connected to a further port of
the CPU 1~0. Signals corresponding to a pending power failure
are further fed to the interrupt port of the CPU 120, by way of
opto-electric isolator 126. It is thus apparent that all signal
and control to and from the accounting unit must be directed by
way of opto-electric isolators, in order to insure the electrical
and physical integrity of this unit. The accounting unit further
includes a plurality of PROMs 127 coupled to ~he address and data
. 25 lines of the CPU 120, each PROM 127 for example, being a E-PROM
type 8755. This unit is connected to an electrically alterable
read-only memory lEAROM) 128, for example, a type ER 3400, serving
as a nonvolatile memory to store data at times during which the
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~ower sLIpply to the postage meter has failed, or has been inten~
tionally disconnected. The working memory for the accounting
system, including the registers for stocing all operational data, ~
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are provided in the CPu 120, this data being trans~erred to
the electrically altera~le ROM 12~ at such time that a
reduction of power is sensed. In order to insure the complete
transfer of data, storage capacitors may be connected in
conventional manner to store adequate power to insure the
proper functioning of the circuit until the transfer of
data has been effected.
A preferred example of the circuit of the printing
unit is illustrated in Fig. 9, this circuit consisting
primarily of the CPU 130, for example, a type ~7~8-8, the
CPU being connected by way of suitable buffers where necessary,
to the I/O devices within the printing unit itself. The
mechanical and opto-electric sensing systems in the printing
unit are conventional and may be generally of the type
disclosed, for example, in U.S. Patent No. 4,050,374 and
aforementioned copending application Serial No. 346,655.
Thus, the CPU is connected to a plurality of opto-electric
sensors (not shown) for sensing of the positioning of the
print wheels, these lines also being connected to enable the
sensing of the privileged access switch 51 of Fig. 2. The
privileged access switch 51 is located within the printing
unit and is accessible only by way of a door sealed by the
post office. These lines of the CPU are further connected
to sense the position of the dater door, the dater door
switch and privileged access switch being strobed by way of
a further output of the CPU 130. ~he LEDs for the optical
sensors are strobed at the proper times by way of another
output of the CPU 130, and still further outputs of the CPU
enable the stepping of the bank and digit stepping motors
for the print wheels. In addition, the CPU 130 has a pair
of ports for serially communicating to and from the accounting
unit. Further, the interposer output from the accounting
unit, and another output of the CPU 130 control a pair
of transistors 131 for energizing the interposer
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solenoid, whereby the interposer solenoid 153 is not energized
until all the pr~conditions are met both in the accounting
unit and the printing unit. ~6 a result, a printing cycle
-cannot commence unless the physical and electrical conditions
in the meter are correct for normal printing. In the printing
unit, it is therefore evident that the program is provided
within the CPU itself.
Postal meters of the above-described form may be providéd
with several modifications. For example, in one modification,
a remote charging feature is available
whereby the key is provided for operation of the three-position
charging switch on the keyboard. The operator of ~he unit may
thus be provided with suitable combination for entry into the
kçyboard, to enable remote charging (i.e., away from the post
office). In such units the privileged access switch is omitted.
In a further modification, the three-position recharging
switch on the keyboard may be controlled by a simple knob, without
the necessity of a key. In this type of a system,
~ the meter may be manually recharged at the po~t office, but the
service functions may be effected locally in a manner si~ilar to
that of remote recharging sys ~m type units.
In other words, recharging of a postal meter of the above
~ype can be effected locally, if devices are provided with a key
for the three-position switch, in which event further security
- 2S is reguired as will be discussed later. On the othe~ hand, in
postal meters having a simple knob switch instead of the key
switch, the "priviIeged accessU~ sealed at the post office, is
provided for man~al recharging. ~ ~ ;
In the normal mode of opera~ion of the system, as above ~ ~
.. . :
discussed, the six display keys, when depressed, ~ffect the
display on the dlliplay paDel o the six par`ameters above noted, -
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i.e., the total in the ascending register of all postage that
- has been printed, the total remaining in the descending register
of postage availabl~, the control sum, the total number of
printing operati~ns of the meter, the value of postage printed
and the number of pieces that have becn printed since the last
batch clear operation o~ the associated registers. The depression
of these keys results only in the numher of concern being displayed
for a timed period after the key is released, for example, two
second~ following which the display will return to the postage
setting
In either type of meter, if the service switch is placed
in the service position, with the three-position switch still in
the operate position, the display function of the display keys
will be different. Thus, depression of the "postage used" key
35 will now result in a display of the current value set in the
dollar unlock reyister in the machine, at or above which an
operator cannot print postage. Postage values a~ove this value
require an additional depression of the set postage key for
-20 operation, in order to avoid accidental printing of excessive
postage values. Depression of the "postage unused" key 36 will
now result in a display of the value in the low postage warning
register at which a warning should be given that the contents of
the descending register are below a determined amount. Depression
of the control or'postage sum" key 37, will now result in the
display of the ~erial number of the postal meter. Depression of
the "piece count~ key 38 wilI now ~esult in a display of the
diagnostic status of the meter. Thi~ display provides an
indication to the serviceman of possible misfunctions. A
depre~sion of the ~batch value" key 39 will now result in a
display of the maximum settable amount, i.e., the maximum amount
- set internally within the meter, above which the metPr cannot
set the print register~. Depression of the "batch count~ key - ,
40 will have no e1Efect in the ~ervice mode.
-20-
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The three-position switch i5 used to effect recharging
of the meter or to effect the change of value~ in the
registers concerned with dollar unlock value, the low postage
-warning amount and the maximum settable amount.
With the remote recharging~ feature,
positioning the three-po~ition switch in either the "enter
combination" or "enter amount" positions enables the customer
to enter combination or amount re,spectively into the meter
via the keyboard with indication on the display. Leaving the
position enterq the display value into the accounting unit
and blanks the display for the next entry. Return of the
three-position switch to the operate position will cause
the accounting unit to complete the recharging routine and
return the meter to normal usage with the recharging amount
added to the postage unused register. The combination for
the remDte recharging ~eature is obtained from a remote data center and is
a random or pseudorandom number which changes with each
recharging for security reasons.
For meters with the manual recharging
-~~ 20 - feature, the recharging mode is effected by breaking,,the seal
of the privileged access door, and flipping of the privil'eged
access switch. The same sequence of operations of the three- ~
position switch described above for recharging the meter are ~,
followed as in those meters having the remote charginq feature. -
In the manual recharging system machine only post office perso~nel are
permitted to effect the change. The combination is a fixed
number known only to the post office and i~ stored within the
meter. Normal speration of the meter may proceed once'the
p~ivileged ac~ess switch has been returned to its operate
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~ 30 position.
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To change values in the registers concerned with dollar
unlock value, the low postage warning amount and the maximum
settable amount the serviceman woula place the meter in the
- service mode by placing the service switch in the service
position. ~he three-position switch is used as described
above for the entr~ of combination and amount values. The
meter will interpret the combination value to indicate which
register is to be changed~
For the re~,ote re harging system n~eter and the manual recharging
system meter if an error has been made in entry, the oc~xence of this
error will be counted, hS constituting evidence of t~per~lg with the machine.
When a determined number of such errors have been made, for
example, 9, since the last setting of the meter, then the
function of the machine in recharging postage will be inhibited.
The return of the meter to operating status in such circumstances
may be effected at the post office. A discussion of the means
to return the meter to full operating status is not of conse~uence
to the present invention and relates to the security of the
meter.
As above discussed, each of the three units of the ~ `
postal meter has a microprocessor with a read-only memory
defining a given program, and the communication between the
units is effected serially and asynchronously. ~his is achieved
in the first place by providing each of the computer systems
with a crystal controlled clocX. Further, the signals are
definea such that the transitions thereof are closely controlled,
whereby it is insured that, if a signal is present, it must be ;~
present within a given time period. As a still further
insurance of the correatness of communication, the bits of a
signal are returned to a transmitter as soon as they are ;~
` ~eceived, for error checking at the transmitter,~whereby
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a "no error" bit may be transmitted immediately following a
data message if the data has followed correctly.
The progr~m of the control unit respon~s to the status
of the postal meter with respect to determined parameters.
A register in the microprocessor of the accounting unit
- holds meter status informatio~, or example, of two bytes,
the bits of which digitally indicate if the meter trip mechanism
requires recocking, if the dater door has not been opened
following the last application of power or is presently open,
if there are insufficient funds to allow printing of the amount
set in the print wheels, if the low postage value has been
reached, if the meter is in a service mode, if the meter is
enabled, if the batch registers are clear, if a trip has been
completed, or if various types of errors have occurred. The
lS status message associated with these bits is not the same as the
diagnostic message noted above that is employed in the service
mode. The accounting unit keeps the control unit informed of
the current status by transmitting status message to the control
unit after power has been turned on and, thereafter, whenever a
change in status occurs, the control unit responds to all such
, :
messages by insuring that the display on the meter is consistent
with the status message as above discussed. These later steps
may include, for example, the display o a row of decimals in
the event of certain errors, the flashing of the decimal point
~ 25 in the event of low postage funas, the flashing of the entire
display in the event of insufficient postage, the displaying of
underscores in the place of blanks if the meter is in the service
-
mode.
An interrupt program in the control unit interrupts the
: io main program of the control unit at regular intervals in order
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to scan the keyboard and keyswitch, and ta drive the display.
In order to prevent the display of spurious characters which
can be produced by sneak currents when more than o~e key is
pressed, the interrupt program will cause the display to go
blank instead. Such values as relate to time, keyboard, and
keyswitch are maintained by the interrupt program for U38 by
the main controller pro~ram.
The main program for the control unit includes the
initiali~ing steps, program steps for the transfer of mqssages
back and forth between the accounting unit and external devices,
and control of the timed display, the checking of the status
message to insure that dater door and reset base. lights are
lit in accordance with the status, responding to the reported
positions of keys, and three-position switch to ascertain
changes of state therein so *hat the control unit subroutine
which corresponds to the function defined for such a state or
change of state will be executed.
The program of the accounting unit includes initialization
procedures to insure that the working registers are brought up
to date, and that no postage has been printed that has not
been accounted for, as well a~ a power down processing program
to effect the transfer of data to the nonvolatile (electrically
alterable) memory in the event that the po~er is shut down or
is failing.
The main program of the accounting unit e~fects the
transmlssion of the meter status message to the control unit
upon request or change in status, determines the effect o~
any currently entered po~tage value on the funding data
3Q currently registerea and maXes any necessary variations in the
~tatus mesRage. The main program also controlR the timing ;~
in the accounting unit for receiving messages from the control
unit and the printer. The accounting unit program further
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includes subroutines for processing of signals in the ~ringing
of the registers up to date when postage is to be printed, and
for controlling the operation of the system when the metex
is tripped. A further subroutine controls the bringing of
the meter status message up to date. In addition an error
checking routine which involves cyclical redundancy chec~ing
is programmed in the accounting unit software. This will be
described in further detail below.
The program of the printer unit includes a main program
having initializing steps, steps for scanning the sensors and
controlling the strobes for the LEDs of the sensors, and the -
processing of messages for communication with the accounting
system. Subroutines are provided for the setting of the
postage wheels, to determine if sensor readings are proper,
15 and to determine if any changes have been made in the outputs
of the various hardware sensors and swi~chès such as the
privileged acces~ and the dater door swltoh.
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In a nlccll~nical l)ostugc meter sccurity is obtainc~
YiU d kcy lock arl~ seal. Oncc thc seal is bro~en and the key
loek is opcrate~ the post oE~ice has access to the mechanisln
of tllc mctcr to cffcct rechar~ing.
tn accordance witll the present invention the kcy lock
has becn replaced with a priveleged access SWitC}I under the
scal an~ a uniquc combination whic}l is ~nown only to thc post
office and intcrnally witllin the meter in its non-volatile
melllory. Ihus a combination lock is provided in the electronic
mcter. Security is improved because each meter llas a uni~lue
combillatioll lock as opposed to, as in the mechanical postage
metcr whcrc a sing~le key was provided access to a farnily of
mcters.
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As an additional function, provisions can be ~nad,e '~
within the above procedures, 3utomatically to remove any funds
remaining' in the meter by clearing the descending register to
zero, upc.n entry of a combination and a new unique amount. The
S customer can then receive a refund or credit based upon the monies
remaining in the meter. This function can be particularly useful
from both a security viewpoint as well as a convenience, when a
meter is being removed from service with unused funds.
; -27-
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A complete flow char-t of -the soEtware functions of
the accounting, control and printiny units is shown in
greater detail in applicant's copending application Serial
No. 363,5~1, filed concurrently herewith and assigned to
the assignee of the present invention. In addition, a
complete printout of the programs actually contained within
the permanent memory of each microprocessor in each of the
accounting, control and printing units, respectively is
disclosed therein.
Variations and modifications in the different
functions performed by the operation of the apparatus of
the present invention can be effected in accordance with
chanyes in the various programs previously set in memory.
.,~, my~,?~ - 28 -
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It is known and understood that the terms postage
meter and postal meter, as used herein, refer to the general
definition of a device for the imprinting of a defined unit
value for governmental or private carrier parcel, envelope
or package delivery, or other like application for unit value
printing. Thus, although the term postal meter is utilized,
it is both known and employed in the trade as a general term
for devices utilized in conjunction with services other than
those exclusively employed by governmental postal services.
For example, private parcel or freight services purchase and
employ postal meters as a means to provide unit value pricing
for individual parcels, including accounting and printing
functions.
The present invention is particularly directed to
use in a postal meter which will employ varying features and
functions, described in differing aspects, in any one or more
of the following groups of applicant's copending patent
applications, including this one, all filed concurrently:
Serial Nos. 363,503 363,504; 363,505; 363,506; 363,507; :
363,509; 363,520 and 363,541. Applicant's U.S. Patent No.
4,266,222, issued May 5, 1981 is also related to these
applications.
While this inventlon has been dis~losed and descrlbed with
reference to a simple embodiment thereof, it will be apparent
that variations ~nd m~dlflcations may be made therein, and it
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intended in the following claims to cover each such variatlon
and modification as falls within the true spirit and scope of
the invention.
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