Real estate abstract
A secure entry system makes use of radio transmissions to communicate
with locks, keys, and related components throughout the system.
The radio transmissions can be made using a paging system, a cellular
telephone system, or any other RF carrier. Some embodiments employ
a cellular telephone in lieu of an electronic key. Others integrate
a paging receiver within an electronic key to provide a unit with
dual functionality. The system is illustrated with reference to
exemplary applications in the industrial site security, real estate
lockbox, and transportation fields. A homeowner key allows the homeowner
greater oversight and involvement. The key includes a privacy feature,
enabling the homeowner to disable the lockbox for a predetermined
period if privacy is desired.
Real estate claims
1. In a method of operating an electronic real estate lockbox system,
the method including providing a house listed for sale with a lockbox,
the lockbox containing a key to the house, compiling data relating
to accesses of the lockbox in a lockbox memory, transferring data
from the lockbox memory to a key associated with a real estate company,
and transferring data from said key to a central database, an improvement
providing an owner of the house with an electronic key;
using the owner key to obtain data from the lockbox memory;
telephonically transferring the obtained data from the owner key
to the central database by acoustically coupling the owner key to
a telephone mouthpiece;
transmitting, by FAX, an interpreted report corresponding to said
obtained data from the central database to a real estate company;
voicing less than all of the obtained data to the owner over a
telephone link using a voice synthesizer system in conjunction with
the central database.
2. An electronic real estate lockbox system that includes an electronic
real estate lockbox attached to a home, a homeowner key secured
by the owner of the home for use with said lockbox, said homeowner
key including a microprocessor, a battery, a button to request privacy,
and communications means for exchanging data with the associated
electronic lockbox, the key further being characterized by means
for restricting access to the lockbox for a predetermined period,
said means including said button operable by the owner at any time
selected by the owner.
3. The electronic real estate lockbox system of claim 2 in which
the key further includes radio transmitter means for relaying a
privacy request from the homeowner key.
4. The electronic real estate lockbox system of claim 3 in which
the system further includes a clearinghouse with an associated radio
receiver for receiving said privacy request, and responding in accord
5. The electronic real estate lockbox system of claim 2 in which
the key further includes an audio transducer for relaying an acoustic
privacy request for the homeowner key.
6. The electronic real estate lockbox system of claim 5 in which
the system further includes a clearinghouse with an associated telephone
connection for receiving said privacy request, and responding in
7. The electronic real estate lockbox system of claim 2 in which
the communications means includes means for relaying a privacy request
from the homeowner key to the lockbox.
8. In a method of operating an electronic real estate lockbox system,
the system including an electronic real estate lockbox attached
to a home and an electronic key, an improvement comprising the steps
of providing the owner of the home with an electronic key temporarily
limiting access to the lockbox for a predetermined interval in response
to the owner's pressing of a single button on the owner's key associated
therewith, whereby the owner is able to press the button at any
time for limiting access to the lockbox for the predetermined interval.
Real estate description
FIELD OF THE INVENTION
The present invention relates to secure entry systems, and more
particularly relates to the use of radio in such systems.
BACKGROUND AND SUMMARY OF THE INVENTION
In the century since radio science was developed, radio signal
transmission has found myriad applications. Some have been in the
field of electronic security systems.
A familiar example is a garage door opener. A radio transmitter
is used to relay instruction signals to a receiver unit, causing
the receiver unit to activate a door opening mechanism.
More sophisticated access control devices operate in conjunction
with a personal access card that includes a battery, a microprocessor,
a receiver and a transmitter. The access control device periodically
broadcasts an interrogation signal, which the card receives when
it is brought into close proximity thereto. In response, the card
transmits an RF reply signal to the access control device, authorizing
access to the secured area. French patent publication 2,604,808
and European patent publication EP 393,784 are illustrative of such
Radio data transmission is sometimes used in home security systems
to relay data from motion, continuity, vibration or other detectors
to a central monitoring unit.
Radio frequency energy is sometimes used to convey operating power
to an otherwise unpowered unit. U.S. Pat. No. 4,851,652, for example,
illustrates a secure entry system in which a passive lock unit is
powered from RF energy radiated from an associated key card. The
lock also receives data from the key by modulation of the same RF
energy. French patent publication 2,542,792 shows such a system
in which a passive key is powered by an RF signal that is coupled
to it by an associated lock.
Radio is sometimes used outside the secure entry field to relay
reprogramming instructions to remote units. U.S. Pat. Nos. 4,525,865
and 4,910,510, for example, disclose pagers and other radios whose
operational characteristics can be reprogrammed remotely by radio.
U.S. Pat. No. 5,020,135 discloses such a system that also features
remote memory dumps and diagnostics from radio transceivers using
radio signals. U.S. Pat. Nos. 4,543,955 and 4,958,632 disclose cardiac
pacemakers and other implantable devices that can be reprogrammed
via use of radio. U.S. Pat. No. 4,713,661 discloses an annunciator
system for buses wherein a sequence of bus stop information can
be programmed into the system via radio. U.S. Pat. No. 5,016,273
discloses a videocassette recorder (VCR) that is equipped with a
paging receiver to provide a number of features, including remote
PCT published patent publication Wo 90/13096 (which corresponds
to U.S. application Ser. No. 07/338,718, filed Apr. 14, 1989) discloses
a "very smart card"-type credit card that is equipped
with a paging (radio) receiver, permitting the card to receive signals
periodically reauthorizing its continued use. The disclosed card
additionally includes a keyboard, microprocessor, a magnetic transducer
(and/or external electrical contacts), and an LCD display.
U.S. Pat. No. 4,766,746, assigned to the present assignee, teaches
that locks and keys can be equipped with radio receivers to provide
a secure entry system with remote. programming capabilities. In
particular, U.S. Pat. No. 4,766,746 discloses a system in which
radio is used to send disable instructions to key units and to send
lockout list data or access codes to lock units.
The present invention expands on the technology disclosed in U.S.
Pat. No. 4,766,746 and provides a number of additional features.
These features will be more readily apparent from the following
detailed description, which proceeds with reference to the accompanying
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a secure access system according to a first
embodiment of the present invention.
FIG. 2 illustrates a secure access system according to a second
embodiment of the present invention.
FIG. 3 illustrates a secure access system according to a third
embodiment of the present invention.
FIG. 4 illustrates a secure access system according to a fourth
embodiment of the present invention.
Referring to FIG. 1, a first embodiment 10 of a secure entry system
according to the present invention includes a lock (or other access
control device) 12 having a cellular, paging, or other RF receiver
14 integrated therein. The lock may be a door lock at an industrial
site, a real estate lockbox, or any other kind of access control
A user who seeks access to the lock establishes communication (by
a cellular telephone, by a conventional telephone, or by some other
communications link 16) to a clearinghouse 18. A series of voice
prompts synthesized by a computer 20 at the clearinghouse and relayed
to the user over the link 16 solicits the user to identify the lock
12 to which access is desired. (The lock is usually identified by
a number, but in other embodiments is identified by more descriptive
information.) The clearinghouse also requests the user's Personal
Identification Number (PIN number). This data may be provided by
the user, for example, using a telephone's Touch Tone pad 22.
If the clearinghouse determines, by reference to a database 24,
that the user should be authorized to access the identified lock,
the clearinghouse causes a radio transmission to the lock 12 to
be made. The transmission, which may be via a system 26 such as
a paging system, a cellular telephone system, or other RF carrier--depending
on the type of receiver 14 with which the lock is equipped--authorizes
an access by the user. Desirably, this authorization is valid only
for a predetermined time period, such as 30 minutes (the "window"
The clearinghouse 18 also desirably reports back to the user regarding
the action taken on the user's request. In the preferred embodiment,
the voice synthesizer reports to the user whether access permission
is granted, as well as information about the window period. An exemplary
report may be, "Your request for access authorization to lock
246 has been approved. Your window of authorization will end at
Before terminating the communications link 16 with the user, the
clearinghouse can relay any status information which should be provided
to the user. Some of this status information can be lock-specific.
For the case of a real estate lockbox system, for example, this
lock-specific status information might include a change in price
of the listed real estate, a reminder to disable a burglar alarm,
a notice that the owner or another real estate agent is at the house,
etc. If the equipment with which the user has contacted the clearinghouse
is equipped with a video display, then graphical data specifically
relating to the property can be provided from the clearinghouse
to the user. This transmission is achieved by slow scan video transmission,
or by such other video format as the bandwidth of the communications
link between the user and the clearinghouse may permit.
The clearinghouse can also relay status information to the user
that is not lock specific. This information often relates to news
regarding administration of the lock system.
It will be recognized that the clearinghouse has knowledge of all
accesses that it has authorized. Such data is desirably compiled
in the database 24 at the clearinghouse and serves as an authorization
log. However, since a user may request authorization to access a
lock, but not actually do so, the authorization log is not necessarily
an accurate indicator of actual accesses. Accordingly, an access
log is also desirably compiled at the lock itself, as described
As noted, the clearinghouse relays to the lock certain data, namely
the fact that an user is coming, the identity of the user, and the
time period during which the user is to be able to access the lock.
By this arrangement, the lock needn't be programmed with a list
of authorized users, or even a list of disallowed users. Instead,
the lock is configured to deny entry to everyone. The exception
is the user identified by a radio transmission--and this user only
for a predetermined period of time. Security is thereby enhanced.
In the preferred embodiment, all of the locks in a system utilize
common radio reception frequencies. Authorization data can be targeted
to different units (or groups of units) by address data included
in the authorization transmission. The use of addressed data packets,
and a representative packet-based paging protocol employing such
addressing, is disclosed in U.S. Pat. Nos. 4,713,808 and 4,897,835.
In other embodiments, targeting can be achieved by time division
multiplexing (i.e. time slot protocol), wherein each receiver awakens
in staggered brief intervals to listen for messages. Still further,
both techniques can be used together. (The systems disclosed in
U.S. Pat. Nos. 4,713,808 and 4,897,835 employ both techniques.)
Of course, in other embodiments, different locks (or groups of
locks) can be fixedly tuned to different frequencies. Still further,
a single lock receiver can be dynamically tuned among several frequencies
in order to assure good signal reception. PCT publication WO 91-00676
discloses a suitable system of the latter type.
When the user arrives at the door, the user must be identified
to the lock. This can be accomplished by one of several identification
means 28. In one, the user keys in a PIN number or other identifying
data onto a keypad associated with the lock. In another, the user
enters a PIN number or other identifying data onto a keypad of a
key, and couples the key to the lock. In yet another, the user carries
an identification tag that is remotely sensed by a proximity detector.
(In some applications, heretofore limited to animals, it is desirable
to surgically affix or implant the identification tag.) A variety
of other physiological identification means, including retinal scanners,
voice print analyzers, and fingerprint sensors, could alternatively
In response to identification of the authorized user at the lock
within the prescribed time period, a lock microprocessor CPU 30
instructs a lock mechanism 32 to unlock. (The type of lock mechanism
employed will obviously depend on the particular application. The
design of a lock mechanism to suit a particular application is well
within the capabilities of one of ordinary skill in this art.) Data
relating to the access is logged into a memory 34 (typically, but
not always, associated with the lock) for subsequent analysis.
Sometimes an authorized user may visit the lock 12, and be sensed
by the lock's identification means 28 (such as a proximity detector),
but not actually access the secured area. In real estate lockbox
systems, for example, this may occur when a visiting real estate
agent and prospective buyer make an external inspection of the listed
property and find it not to the buyer's liking, prompting them to
leave without actually gaining access to the lockbox. In an industrial
site security system, a night watchman may check the perimeter of
a secured building without going in.
In such situations, it is often desirable to confirm actual entry
of a person into the secured area, and log this fact into the access
log memory. Often such confirmation can be obtained by a sensor
associated 36 with the door to the secured area. A door latch, for
example, can be equipped with a sensor to indicate when the bolt
is retracted. A door knob can be equipped with a capacitive sensor
to sense its use. A real estate lockbox can be equipped with a sensor
to confirm that the key compartment is actually opened. Such sensors
can be implemented by those of ordinary skill in this art without
Other sensors 36 can be used to confirm the presence of a person
within the secured area immediately following the expected entry.
Such sensors are well known in the art and include motion detectors,
door mat entry switches, break-beam optical sensors, etc.
An element shared in common with all such approaches is that they
involve participation by the user--participation that would not
generally occur absent actual access.
As noted, the data relayed by radio from the clearinghouse to the
lock desirably includes data specifying a time window. A timer 38
in the lock (which timer can be implemented by circuitry or by appropriate
programming of the CPU 30) checks that the access takes place within
the specified window.
(In the preferred embodiment, the time window begins at the time
of the user/clearinghouse transaction. In other embodiments, however,
it may be desireable to authorize a requested access well in advance,
in which case the time window may not start for a matter of hours
or days after the user/clearinghouse transaction.)
In a variant of the illustrated embodiment, the clearinghouse authorizes
a particular user's access for a variable time period. For example,
the time period may last until 9:00 p.m., regardless of when it
begins, or it may last until another user is authorized to access
As noted, it is conventional for secure access systems to record
data relating to lock access. If the power supply 40 (which may
be a battery) at the lock permits, the lock can be equipped with
a transmitter 42 to relay reports of lock accesses to a central
station. (While FIG. 1 shows the transmitter and receiver circuits
using separate antennas, it may be preferable to share a single
antenna between both circuits.) In one such embodiment, access data
is radio-forwarded in real time, as the accesses occurs. In another
embodiment, a batch system is used, wherein access data accumulates
in the lock memory 34 until a threshold number of entries is reached,
at which time an RF transmission is made. As with other RF transmissions
described herein, these transmissions can be made using a cellular
telephone service, if desired.
In other arrangements, of course, the data can be manually collected
from the lock memory, such as by a key with access log-reading capability.
A number of such keys are disclosed in the electronic lock patents
In yet other arrangements, the access log data is RF-transmitted
to the clearinghouse, but programming instructions and authorization
data are disseminated manually, such as by keys with programming
capabilities, again as disclosed in the electronic lock patents
The foregoing arrangement is particularly well suited for use in
newly constructed houses. A lock 12 can be installed on the house
during construction and can be used by the local real estate board
in lieu of a keybox to admit authorized agents and prospective buyers.
Thereafter, when the house is sold, the lock can remain on the door
for use by the purchaser, if desired (or alternatively can be disabled).
A purchaser might find it advantageous, for example, to let others
admit themselves into the house, provided a record of such entries
is maintained (which lock 12 would do). During this period, the
purchaser would have exclusive rights to program the lock through
the clearinghouse 18. When the house is later offered for sale,
authorization to program the lock can again be extended to the local
real estate board, again permitting the house to be shown by authorized
In some real estate lockbox situations, the house listed for sale
is occupied by the present owner, who may not want interruptions
at certain times (for example, when taking a bath). The preferred
embodiment permits such a homeowner to call the clearinghouse and
instruct, by Touch Tone commands, that no agents are to be authorized
within a "privacy" period that is defined by the homeowner.
Agents seeking authorization during the privacy period would be
notified by the clearinghouse of the temporary inaccessibility of
In a variant of the foregoing embodiment, the lockbox is equipped
with a "privacy" button that can be pushed by the homeowner
to effect an hour long privacy period. If the lockbox is equipped
with a transmitter, this change in status can be relayed to the
clearinghouse, which again provides the status information to inquiring
In yet a further embodiment of the present invention, the homeowner
is provided a limited function key. This key allows the homeowner
to download access log data from the lockbox on the home into the
key, and relay it (e.g. acoustically via the telephone mouthpiece,
or by radio) to the clearinghouse. The clearinghouse, in turn, adds
the downloaded data to its master database, and can send an updated
report (e.g. by FAX) to the agent/brokerage who listed the home.
The clearinghouse can also use its synthesized voice to recite certain
information, such as the number of times the house has been shown,
to the homeowner over the telephone. Such an arrangement spares
real estate agents the need to visit a house to download data, while
giving homeowners a greater sense of involvement and oversight of
The use of a homeowner key opens a number of possibilities on the
"privacy" period discussed above. A homeowner key can
include a "Privacy" button, and can be used to effect
a privacy period at the homeowner's convenience (rather than providing
a "Privacy" button on the lockbox).
In one such embodiment, the homeowner key is associated with a
radio transmitter so that, when the Privacy button is pushed, corresponding
instructions are sent to the lockbox or the clearinghouse that the
lockbox is not be opened for the following, e.g., 60 minutes. (If
transmitted to the clearinghouse, the clearinghouse can relay the
lockout period data to the lockbox. Alternatively, if the system
is one that relies on key preauthorization, the clearinghouse can
simply refuse to authorize any keys to access the associated lockbox
for the following 60 minutes.)
An another embodiment, the homeowner key can effect the same operations
by audio, rather than radio, coupling. That is, the homeowner can
make a telephone call to the clearinghouse and acoustically couple
the key to the telephone mouthpiece. Using a transducer in the key,
the key can relay the privacy request to the clearinghouse.
In yet a further embodiment, the clearinghouse is left out of the
privacy operation. Instead, the homeowner simply engages the key
with the lockbox and instructs the lockbox to begin a privacy period
by pressing the "Privacy" button on the key.
If a real estate agent attempts to access a lockbox during a privacy
period, the lockbox can indicate this fact to the agent, either
by a corresponding message displayed on the agent's key, or by a
characteristic tone pattern (e.g. if the key isn't equipped with
a display). If a message is displayed, it can detail the number
of minutes remaining in the current privacy period.
It will be recognized that one application of the foregoing radio
authorized access control technology is implementation of "Star-Trek"-type
doors. Such doors are radio-programmed periodically with the identities
of persons permitted to pass therethrough. A proximity sensor on
one side of the door senses the identity of an approaching user,
checks the door lock's memory 34, and opens the door if the user
is found to be authorized. A second sensor is desirably used on
the opposite side of the door. This sensor confirms the passage
of the person through the door, and can also sense the approach
of persons from the other direction. Together, the two sensors provide
redundant data confirming whether a person is entering or leaving
the secured area.
The door's memory can be reprogrammed with updated authorization
data daily, or at such other interval as may be appropriate. A user's
authorization can remain valid until the lock is next radio-reprogrammed,
at which time the user must be reauthorized if the user's access
rights are to continue.
In the preferred form of the foregoing embodiment 10, the system
is not limited to authorizing just a single key for a given lock
at any given time. Instead, the system can authorize a plurality
of keys for a given lock, either all for the same time window or
for overlapping time windows.
FIG. 2 shows a second embodiment 44 of the invention which is similar
to that shown in FIG. 1, except that the unit with the RF communications
capability is the key 46 rather than the lock 12'. Thus, when a
user's request to access a particular lock 12' is verified by the
clearinghouse 18', an authorizing (also known as enabling) signal
is sent by radio to that user's key 46. Data defining a time window
is also desirably sent and limits the time period within which the
key is effective. The enabling data enables the key only to access
the lock requested through the clearinghouse.
In this embodiment, a simpler lock 12' can be used--one that responds
to any key (provided, of course, that the key has first received
an enabling signal). System maintenance is thereby facilitated,
since keys requiring maintenance can be more readily be transported
to a maintenance facility than can locks.
Although the interface between the key and lock is not particularly
detailed in FIG. 2, a number of known interfacing techniques can
be used. These techniques include optoelectronic coupling (such
as disclosed in U.S. Pat. No. 4,727,368 and others), RF coupling
(such as disclosed in U.S. Pat. No. 4,851,652 and others), inductive
coupling (such as disclosed in U.S. Pat. No. 4,766,746 and others),
and direct electrical coupling (such as disclosed in U.S. Pat. No.
4,594,637 and others).
In variations of this embodiment 44, of course, the lock can be
quite sophisticated and can employ many or all of the features disclosed
herein and in the patents cited below.
Since the lock 12' in this second embodiment needn't have its own
power source (i.e. to power a receiver), the lock can be powered
from the key. Illustrative techniques for powering a lock from a
key are disclosed in U.S. Pat. Nos. 4,594,637, 4,851,652, and in
copending applications Ser. Nos. 07/740,424 and 07/790,642.
Desirably, this second embodiment 44 includes provision for compiling
an access log--preferably in addition to the authorization log maintained
by the clearinghouse 18'. In one form of the invention, such a log
is maintained in a memory 48 in the key 46. Key-based access log
systems are disclosed, by way of example, in U.S. Pat. No. 4,916,443
and in copending applications Ser. Nos. 07/740,424 and 07/790,642.
Means for assuring that access log data is dumped periodically from
the key memories are also disclosed in these cited references.
Again, if the key power supply 40' permits, the key can be provided
with a transmitter 42' to relay access log data to a central station,
either in real time or in batch fashion. In one form of the invention,
the key uses rechargeable batteries and is connected to a recharger
periodically. When the key is so connected, the radio transmission
from the key takes place--taking advantage of the additional power
available from the recharger's power supply. If desired, the radio
transmission circuitry and antenna can form a part of the recharger
unit, with the data being transferred thereto over the same contacts
that provide recharging power to the key.
In another form of this embodiment, an access log can be maintained
in a memory in the lock. Access log data stored in such a lock memory
can be uploaded to a key using technology such as disclosed in U.S.
Pat. Nos. 4,766,746, 4,800,255, and in copending applications Ser.
Nos. 07/740,424 and 07/790,642. A self-building database system,
like that disclosed in U.S. Pat. No. 4,916,443, can also be advantageously
incorporated in such an embodiment.
Once access data has been uploaded from the lock memory to the
key, it can be relayed to a central database in a variety of ways,
such as acoustic data transmission, wired data transmission, etc.,
as disclosed in the just-noted patent references, as well as by
the above-described radio technique.
If desired, rather than enabling keys on an as-needed basis, the
clearinghouse can make a daily (or hourly, etc.) transmission authorizing,
for another day (or hour, etc.), all keys in the system whose users
are in good standing with the system proprietor. If the authorization
is valid only for an hour, the clearinghouse can effect a lockout
from all locks between the hours of, say 9:00 p.m. to 6:00 a.m.
by discontinuing the authorization transmissions between 8:00 p.m.
and 6:00 a.m. In embodiments employing paging transmissions to communicate
with keys, a key can be equipped with a signalling means 47 (such
as a beeper, vibrator, and/or alphanumeric display) so that it can
also serve a conventional pager function, in addition to serving
as a key.
A third embodiment 50 according to the present invention is shown
in FIG. 3 and utilizes a cellular telephone 52 as the identification
In this embodiment, a user operates the cellular telephone 52 to
call the clearinghouse 54 and request access to a particular lock
56. After suitable verification (by a PIN number or the like), the
clearinghouse transmits an RF signal to the identified lock and
causes it to briefly make itself susceptible to being unlocked (such
as for 30 seconds). Within this interval, the user must perform
some manual operation (such as pushing on a door) to complete the
unlocking operation. If the manual operation is not completed within
the allotted period, the lock resecures itself.
In a variation of this embodiment, the clearinghouse does not make
an authorization transmission to the lock. Instead, it RF-transmits
authorization data back to the cellular telephone in the form of
audio tones. The user acoustically couples the telephone to the
lock to transfer these tones to the lock to thereby authorize the
In a further variation of this embodiment, the cellular telephone
52 does not transmit to the clearinghouse. Rather, its transmitted
RF signal is received by the lock 56 itself, and the user operates
the buttons on the telephone as he would buttons on a key card to
gain access to the secured area.
In one such embodiment, the lock transmits a verification request
to the clearinghouse after receiving the direct RF request but prior
to permitting the requested access. In a second such embodiment,
the lock checks whether the user identified by the button operations
is on a list of authorized users (or on a list of locked out users)
maintained in a lock memory 58. In a third embodiment, the lock
simply permits access without any verification checks.
By all of these embodiments 50, the user needn't carry an access
card or similar device. Instead, the user relies exclusively on
a cellular telephone. This aspect of this invention is believed
to have particular promise in view of the growing ubiquity of cellular
telephones, especially in professions such as real estate.
While the foregoing description of the third embodiment has focused
on the use of a cellular radio transmission to transmit access-related
data to a lock, it will be recognized that a variety of other data
can likewise be transmitted. For example, an authorized user can
issue instructions through a cellular telephone causing the lock's
operating characteristics to be reprogrammed. In U.S. Pat. No. 4,766,746,
and in copending application Ser. Nos. 07/740,424 and 07/790,642,
for example, locks are disclosed that include a memory in which
"characterization data" is stored. Any of the data in
such a characterization memory (such as data determining daily disable
times, timing constants, function enables, etc.) can be altered
by suitable instructions issued by a user and received by the lock
via a radio transmission.
A fourth embodiment 60 according to the present invention is shown
in FIG. 4 and is described, by way of example, in the context of
an access control device for a delivery truck 62.
Delivery trucks are opened several times during a single run, raising
inventory control issues. In accordance with this embodiment of
the invention, a delivery truck is equipped with an electronic access
control device 64 that guards against unauthorized opening.
In the illustrated embodiment, the delivery company calls a clearinghouse
66 and identifies the sequence of deliveries the truck is to make.
Each possible destination is assigned an identification number,
and the desired sequence is programmed by entering (using a Touch
Tone pad or the like) the numbers corresponding to the scheduled
deliveries in their proper order. After suitable verification checks,
the clearinghouse transmits to the targeted truck access control
device 64 the authorized schedule of stops, which data is received
and stored in a memory 68.
When the truck arrives at its first delivery stop, the truck access
control device 64 senses this fact by detecting an identification
device 70 maintained at that location. The identification device
may be a proximity card mounted at the loading dock, or may be an
electronic key carried by a manager employed at the first delivery
stop. If the detected identification device corresponds to the first
expected stop that had earlier been programmed, the truck access
control device unlocks, permitting access to the truck's contents.
A record of this access is logged in the access control device memory
68, providing data as to the time of the access and the location
and/or identity of the accessing party.
When the truck thereafter goes to its second stop, this process
If the truck visits an unauthorized location, the access control
device will sense either the absence of an identification device,
or will sense an identification device that does not correspond
to an authorized stop. In either case, the access control device
will block access to the truck's contents.
Although the access control device 64 is not particularly detailed
in FIG. 4, it can take the same form as lock 12 of FIG. 1 (but with
a lock mechanism adapted to secure the doors of a delivery truck).
In the above-described first form 10 of the invention, a limited
period of authorization (a "time window") is sometimes
employed as an additional safeguard against unauthorized accesses.
Time windows can be employed in the FIG. 4 form of the invention.
However, due to foreseeably unpredictable delays in completing scheduled
delivery runs, a different additional safeguard is more commonly
used. That safeguard is to require that the truck make its scheduled
deliveries in the order they are scheduled. If a delivery stop is
made out of the programmed sequence, the access control device 64
will refuse to open.
The route sequence can be modified at any time by new transmissions
from the clearinghouse. Thus, if circumstances make it impossible
to complete the deliveries in the order scheduled, the driver can
call the delivery company and ask that the schedule be suitably
revised. The company can then call the clearinghouse and cause the
access control device to be reprogrammed accordingly.
In a preferred form of this embodiment, the truck security system
is integrated with a satellite vehicle locator system, which may
be of the sort disclosed in U.S. Pat. Nos. 4,897,661, 4,897,642,
4,359,733 or 4,239,447.
In another preferred form of this embodiment, the lock device transmits
data back to a central station identifying the identification devices
as it encounters them. By this arrangement, the truck can be tracked
through its route.
While the above-described form of the fourth embodiment provides
the radio-equipped (and radio-programmable) lock on the truck, and
radio-less identification devices at the various delivery stops,
in other forms of this embodiment these elements can be transposed.
That is, a radio-less lock on the truck can cooperate with radio-reprogrammable
identification devices at the various delivery stops to open the
truck lock if the radio-reprogrammable identification devices have
been suitably programmed.
In high security applications of the foregoing embodiments, the
access control device can be configured to require the presence
of two (or more) authorized users before permitting access to the
secured area. If two different authorized users are not detected
within a given period (such as 60 seconds), the lock will refuse
to unlock. Another high-security variation requires a specific sequence
of users. That is, a system can require that a predetermined user
accesses the lock before any other users gain access. This is useful,
for example, when a manufacturing facility desires that a manager
be present in a given area before any other employees are admitted.
A related variant is to require the presence of multiple users
at multiple locations within some window of simultaneity (such 5
seconds). This is useful, for example, in the start-up of very large
machinery (such as a newspaper printing plant) which may require
the presence of monitoring personnel at a variety of locations at
a given time. Radio transmissions can be employed to confirm the
presence of such persons at their respective stations at the moment
of start-up. If such persons are not detected, the machinery is
locked from operating.
In yet other high security applications, it is desirable to RF-preauthorize
not just the key or the access control device, but rather to RF-preauthorize
Many applications presently served by other security mechanisms
can be more advantageously served by a secure entry system according
to the present invention. Accordingly, it is often desirable to
implement the access control device of the present invention in
a fashion that facilitates its retrofitting into existing applications
As is disclosed more fully in the electronic lock patents listed
below, it is often desirable to partition a system (or site) into
different zones, each having different access codes or authorization
levels. By this arrangement, different classes of users can readily
be assigned permission to access different access control devices
within the system.
It will be recognized that in embodiments employing radio transmissions
from power-limited devices, the range of transmission may be limited.
Transmissions may also be degraded by the location of the device
when transmitting and the characteristics of surrounding terrain.
Accordingly, it is often desirable to provide one or more conventional
repeater stations throughout a geographical area served by the system.
Such stations receive the weak signal from a power-limited device,
amplify it, and rebroadcast it to the destination station. In a
sophisticated system, a geosynchronous satellite can be employed
as a repeater. U.S. Pat. Nos. 4,189,675 and 4,831,619 show systems
of this sort. Alternatively, path losses associated with transmissions
to geosynchronous altitude can be greatly reduced by employing a
plurality of low altitude satellites. Yet another option is use
of a plurality of repeater satellites in elliptical orbit, as disclosed
in U.S. Pat. No. 4,854,527.
It will further be recognized that the transmissions from the clearinghouse
to the receiving units are desirably made redundantly so as to reduce
the likelihood of a failed transmission. Systems for redundantly
transmitting messages in paging systems are well known and are disclosed,
by way of example, in U.S. Pat. Nos. 4,897,835 and 4,713,808.
In the preferred embodiments, the transmissions from the clearinghouse
to the receiver-equipped units are made in an encoded fashion so
that an RF eavesdropper cannot readily decipher the outgoing data.
While, in the above-described systems, the authorization signal
is transmitted in advance of an encounter between a user and an
access control device, in alternative embodiments this needn't be
the case. For example, an access control device can detect the identify
of a user, inquire of the clearinghouse whether the user is authorized,
and if so permit access to the secured area. Delays associated with
the transmission from the access control device to the clearinghouse,
the computer check at the clearinghouse, and the transmission from
the clearinghouse back to the access control device, however, make
such a system unsuitable for many applications.
Voice identification systems suitable for use with the present
invention are disclosed, inter alia, in U.S. Pat. Nos. 5,023,901,
4,989,249, 4,843,377, 4,833,717, 4,601,052, 4,378,469, 4,100,370
and 4,078,154, and references cited therein.
Retinal identification systems suitable for use with the present
invention are disclosed, inter alia, in U.S. Pat. Nos. 5,055,658,
4,993,068, 4,975,969, 4,641,349 and 4,109,237, and references cited
Fingerprint identification systems suitable for use with the present
invention are disclosed, inter alia, in U.S. Pat. Nos. 4,995,086,
4,983,036, 4,977,601, 4,944,021, 4,783,823 and 4,690,554, and references
Proximity identification systems suitable for use with the present
invention are disclosed, inter alia, in U.S. Pat. Nos. 4,935,724,
4,888,474, 4,863,546, 4,855,583, 4,808,803, 4,717,816, 4,617,876,
4,612,877, 4,546,241, 4,475,481, 4,455,484, 4,408,122 and 4,226,361,
and references cited therein.
Electronic lock system technology, including real estate lockbox
technology, suitable for use with the present invention is disclosed,
inter alia, in U.S. Pat. Nos. 3,857,018, 3,878,511, 3,906,447, 4,079,605,
4,092,524, 4,148,012, 4,148,092, 4,201,887, 4,325,240, 4,353,064,
4,411,144, 4,439,670, 4,509,093, 4,525,805, 4,532,783, 4,558,175,
4,575,719, 4,609,780, 4,665,397, 4,727,368, 4,766,746, 4,777,556,
4,800,255, 4,808,993, 4,851,652, 4,864,115, 4,887,292, 4,896,246,
4,914,732, 4,916,443, 4,929,880, 4,947,163, 4,988,987, 5,014,049
and 5,046,084, and in copending applications Ser. Nos. 07/740,424,
07/790,642 and 07/806,801, and references cited therein.
In certain embodiments, the field of the present invention encompasses
cellular communication techniques and systems. The artisan is thus
presumed to be familiar with this field of art, which includes--by
way of cursory example--U.S. Pat. Nos. 4,965,820, 4,932,049, 4,887,265,
4,706,273 and 4,697,281.
More generally, the present invention encompasses the field of
RF communications equipment, with which the artisan is also presumed
to be familiar. U.S. Pat. Nos. 5,031,233, 5,029,237, 4,944,025,
4,897,835, 4,885,802 and 4,713,808 are cited as illustrative of
miniaturized RF receivers known in this art.
The disclosures of the prior art and pending applications referenced
in the foregoing specification are incorporated herein by reference.
From the foregoing, it will be recognized that the present invention
permits, among its many other features, the access parameters of
doors or other access control devices to be customized by RF transmissions,
rather than by visits with a programming device or by wiring to
a central control station.
Having described the principles of our invention with reference
to several preferred embodiments and variations thereon, it should
be apparent that the invention can be modified in arrangement and
detail without departing from such principles. For example although
the invention is described with reference to secured doors, trucks
and real estate lockboxes, it is readily applicable to other uses.
Computers, cars and file cabinets, for example, all can be equipped
with control systems according to the present invention to assure
that only authorized persons gain access thereto. (In many such
applications, the car or other device is already equipped with one
or more other security mechanisms. A device according to the present
invention can thus be employed to provide an additional level of
safeguard. A car, for example, is already provided with an ignition
lock to deter theft. A proximity card-based system according to
the present invention can be added for increased security. When
the user parks the car in his home garage or other secure locale,
the identification card can be left in the car, rendering the lock
"unlocked." However, when parking in less secure locales,
the user can take the card out of the car to provide additional
Although the preferred embodiments have been described as including
certain combinations of features, alternative embodiments can readily
be designed that include other combinations of the features disclosed
herein and in the documents incorporated by reference.
Accordingly, it should be recognized that the foregoing embodiments
are illustrative only and should not be taken as limiting the scope
of our invention. Instead, we claim as our invention all such modifications
as may come within the scope and spirit of the following claims
and equivalents thereto.