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BACKGROUND OF THE INVENTION
This invention relates to telephones used in connection with, e.g.,
cellular telephone systems, and particularly to cellular telephones used
in conjunction with telephone-accessible audio-response systems such as
voice mailbox systems, stock quotation services, and so forth.
Systems of this type are quite familiar. A caller may access, e.g., a voice
mailbox system by dialing an appropriate telephone number, e.g., on a
DTMF-equipped telephone. When the voice mailbox system "answers the
phone," it transmits a series of audio messages inviting the caller to
enter a password. The caller may gain access to a voice mailbox by
entering keystrokes that correspond to the correct password for that
account, whereupon the voice mailbox system plays back any audio messages
stored in its memory (e.g., voice messages left by previous callers).
SUMMARY OF THE INVENTION
In accordance with the present invention, a telephone unit is programmed to
perform an automatic voice mailbox check. The telephone includes a
user-programmable memory and is controlled by logic circuitry which is
programmed to perform a sequence of operations upon a specified action by
a user, e.g., upon power-up of the telephone unit.
If a theft alarm and/or other similar security features are activated, the
logic circuitry waits to perform the remaining operations until
deactivation of the feature. A preprogrammed telephone number for access
to a voice mail system is retrieved from the memory. The preprogrammed
telephone number may include zero or more pause commands and service
access codes.
The logic circuitry then generates a signal to place a call to the voice
mail system, including pausing where indicated by pause commands in the
preprogrammed telephone number. Upon the establishment of a connection
with the voice mail system, the logic circuitry waits for the user to
press a sequence of one or more characters upon a keypad. When a sequence
is pressed, the manual override capability is disabled and the sequence is
evaluated.
During the initial signalling to establish a connection with the voice mail
system, the logic circuitry enables a manual override capability. If a
keystroke sequence entered manually by the user is not recognized by the
logic circuitry as a voice mail identification number (or as a command to
recall a voice mail identification number from a location in the memory),
the logic circuitry assumes that the sequence represents an attempt to
perform another function (e.g., dialing a different number). The logic
circuitry then terminates any connection with the voice mail system and
processes the keystroke sequence in the normal fashion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is block diagram of a typical mobile cellular telephone and its link
with a fixed switching unit;
FIG. 2 is a block diagram of components of such a telephone;
FIG. 3 is a block diagram depicting possible arrangements of an
audio-responsive system (using a voice mailbox system as an illustration);
FIG. 3a is a flow chart of typical operations of such a system from a
caller's perspective;
FIG. 4 is a flow diagram of logical operations programmed for execution by
the telephone in accordance with the invention;
FIG. 5 is a flow diagram of specific logical operations of part of FIG. 4;
FIG. 6 is a flow diagram of other specific logical operations of part of
FIG. 4;
FIG. 7 is a flow diagram of yet other specific logical operations of part
of FIG. 4;
FIG. 8 is a flow diagram of another specific set of logical operations of
part of FIG. 4.
Throughout the following detailed description, similar reference numerals
refer to similar elements in all Figures of the drawings.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
An illustrative implementation of a microprocessor-based telephone system
in accordance with the invention is presented here. The illustration uses
an automobile cellular phone as an example, but it will be understood by
those of ordinary skill that the invention can be implemented in virtually
any telecommunications system.
Telephone Linked to MTSO
FIGS. 1 and 2 show a typical automobile cellular telephone unit 2 having a
unique mobile identification number (MID) stored in a suitable location
such as an electrically eraseable programmable read-only memory (EEPROM,
not shown). Telephone units of this kind are well known in the art and are
described here only in sufficient detail to aid understanding the
invention.
The telephone unit 2 includes a handset 4 having a keypad 5; equivalently,
the keypad 5 could be located separately from the handset. Also included
in the telephone unit 2 are a speaker 6 and a microphone 7, shown as being
mounted within the handset 4 but either or both of which could
equivalently be mounted apart from the handset, either separately (e.g.,
in a telephone operator's headset or in wall mountings), or approximately
together (e.g., in a walkie-talkie or speakerphone configuration). It will
be apparent to those of ordinary skill that if the keypad 5, the speaker
6, and the microphone 7 are all located apart from the handset 4, the
handset can be dispensed with.
A transceiver 8, ordinarily built into the telephone unit 2, exchanges
signals (via, e.g., an antenna 10) with a mobile telecommunications
switching office (MTSO) 12, typically via radiotelephone signals relayed
by one of several cell sites 11 that are in turn connected with the MTSO
12 via a landline. The MTSO 12 is ordinarily connected with a telephone
company switching unit 12a via a high-capacity landline or similar
connection.
Status Display and Logic Circuitry
A status display 13 shows the status of the telephone unit 2. The status
display 13 typically includes a NO SVC indicator to show that no cellular
telephone service is available; and a ROAM indicator to show that the
telephone unit 2 is outside its usual service area.
The transceiver 8 and antenna 10 are shown as being separate from the
handset 4, but either or both could equivalently be built into the
handset. The MTSO 12 could equivalently be another telephone or similar
unit if both telephones had appropriate signalling, switching, and call
processing capabilities.
Those of ordinary skill having the benefit of this disclosure will
appreciate that the signal exchange may utilize any of a wide variety of
transmission systems that are equivalent for purposes of this description.
These include, for example, radio, electrical-type wire (such as telephone
landlines), modulation of light beams (e.g., in fiberoptic networks or
laser beams), and so forth. The signal exchange may use one or more of
these media alone or equivalently in combination. Whether specific
components such as the antenna 10 are needed for a given implementation of
the invention will depend in part on the transmission system selected for
implementation.
The operation of the telephone unit 2 is controlled by logic circuitry 14.
The logic circuitry 14 may be implemented in the form of, e.g., a
microprocessor which executes program statements stored in a storage
device such as a read-only memory, or equivalently by discrete logic
components or one or more custom semiconductor chips.
Those of ordinary skill will appreciate that a sequence of numbers to be
dialed by the telephone unit 2 is processed by the logic circuitry 14
generally as follows, both in the prior art and in connection with the
invention. Under control of the logic circuitry 14, the transceiver 8
transmits a cellular control signal to a cell site 11 over a signalling
channel. The control signal includes a request that the MTSO 12 dial a
specified telephone number and assign a voice frequency or channel for use
by the telephone unit 2.
The programming of the logic circuitry 14 includes the capability of
recognizing a unique "pause" command in a dialing sequence and of pausing
a signalling operation (such as dialing of a number) for a specified
period of time when a pause command is encountered.
The telephone unit 2 includes a read-write memory 16, accessible to the
user and whose contents will not be affected by telephone power-downs of
ordinary duration. For example, the memory 16 may equivalently comprise an
EEPROM programmable by the user, a CMOS memory chip, or a conventional RAM
with an independent power supply, any of which may possibly be implemented
as part of a custom semiconductor chip.
It will be understood that telephones used in typical cellular systems are
capable of generating both dual tone multi-frequency (DTMF) signals (DTMF
signals produced by Bell telephones are referred to by the "Touch-Tone"
trademark) and EIA standard IS-3-D cellular control signals.
A theft alarm 18 is shown in phantom as being connected by way of example
to the transceiver 8. The theft alarm 18 may be of a variety of types well
known to those of skill, e.g., an automatic-dialing type, one which sounds
the car's horn (and thus need not be connected to the transceiver 8), etc.
The theft alarm 18 forms no part of the invention and is shown in the
drawings for purposes of clarity.
It will be understood by those of ordinary skill having the benefit of this
disclosure that the specific details of any given implementation may vary
considerably depending on the particular microprocessor or other
components selected. The selection of components and the arrangement and
programming thereof will be a matter of choice by the artisan for the
particular application desired.
Voice Mailbox System
A voice mailbox system 310 is illustrated in FIG. 3. The voice mailbox
system is a readily implementable variation on conventional systems of
this type and is illustrated for purposes of clarity.
The voice mailbox system 310 may be maintained at or near the MTSO 12
(e.g., by the cellular telephone service company). It may be designed so
that when an automatic voice mailbox check is performed as described
herein, the MTSO 12 transmits a signal to the voice mailbox system 310
that identifies the specific telephone unit 2 performing the check (e.g.,
by MID). This is of course possible using conventional techniques, since
the telephone unit 2 identifies itself to the MTSO 12 in the course of
initiating any call.
Equivalently, a similar voice mailbox system 320 may be maintained at
another location (e.g., by another company), to be accessed over telephone
company lines.
As shown in FIG. 3A, the voice mailbox system 310 is designed to respond to
a specific sequence of DTMF or similar signals. These signals are
explained in more detail below.
Memory Check and Self-Test
FIG. 4 is a high-level block diagram flow chart of the programming of the
logic circuitry 14, for controlling operations performed by the telephone
unit 2 in certain specified events.
Generally, the logic circuitry 14 initiates a conventional memory check and
self-test upon DC power-up, as shown at process 410.
Theft Alarm and Other Checks
The next operation assumes that an automobile theft alarm 18, shown in
phantom in FIGS. 1 and 2, is connected to or built into the telephone unit
2.
Referring to FIGS. 4 and 5, when the memory check is completed at process
410 (FIG. 4), the logic circuitry 14 goes into a loop 515 (FIG. 5) to wait
for deactivation of the theft alarm, as indicated by process 517. The wait
for deactivation may include automatic dialing of a preselected security
number and the transmission of an alarm message after a certain time has
elapsed, in accordance with techniques known to those of ordinary skill.
Likewise, if the telephone unit 2 is locked (mechanically, electronically,
or through software), as shown at process 520, the logic circuitry 14 goes
into a loop 520 to wait for the phone to be unlocked.
As shown at decision box 525, the logic circuitry 14 checks a status
indicator (e.g., a flag in the memory 16) to determine whether the
telephone unit 2 may be used for automatic access to the voice mailbox
system 310. The status indicator may be set in any conventional manner.
For example, the owner or usual user of the telephone unit 2 may enter a
specific keystroke sequence (possibly including a secret password) upon
the keypad 5 that is interpreted by the logic circuitry 14 as calling for
disabling the automatic voice mailbox check. Another specific keystroke
sequence (again possibly including a password) is interpreted as
re-enabling the automatic check. If automatic access is disabled, the
logic circuitry aborts the automatic voice mailbox check; the user, of
course, may check the voice mail manually by dialing the appropriate
numbers in the usual manner.
It will be understood by those of ordinary skill, of course, that the logic
circuitry 14's programming for handling the theft alarm 18 and locking
features are exemplary of programming for handling any number of similar
authorization checks, equivalent for purposes of this description, wherein
it is desired that the logic circuitry wait until certain conditions are
established before initiating the voice mail check.
Manual Override Enablement
The logic circuitry 14 enables a manual override, as indicated by process
420 and at FIG. 6, if and when the theft alarm 18 is timely deactivated
and other authorization checks are completed. The manual override is a
conventional interrupt handling routine: if a keypress occurs on the
keypad 5, the logic circuitry 14 interrupts its current activity and
control branches to an appropriate service routine in accordance with
known techniques. This enables user keystrokes to be given priority over
automatic operations.
Selection of Paging and Signalling Channels
As shown at process 715 of FIG. 7, under control of the logic circuitry 14
the telephone unit 2 next proceeds in a conventional manner to monitor one
or more prespecified sets of paging frequencies (referred to as paging
channels), to determine the system identification (SID) code, if any,
being broadcast by an MTSO 12 on the respective paging channels. Those of
ordinary skill will recognize that an SID is a code that, within the
service area in question, is uniquely associated with a particular company
offering cellular telephone service. An MTSO 12, operated by a cellular
service company, commonly broadcasts the associated SID from time to time
on the paging channels that are assigned to that company for use within
the service area.
The logic circuitry 14 may be programmed so that if a "home SID" (i.e., an
SID of a cellular service company with which the user has an account
established) is detected, the logic circuitry 14 places a call in a
conventional manner (and as described below) by generating appropriate
signals on the signalling channel associated with the selected paging
channel. In such programming, if a home SID is not detected, the logic
circuitry 14 discontinues the automatic voice mail check and proceeds to
"ready" mode.
Equivalently, the logic circuitry 14 may be programmed to use paging and
signalling channels associated with a nonhome SID if a home SID is not
detected.
Initiation of Call to Voice Mail System
Once a paging and signalling channel pair has been selected for use, the
logic circuitry 14 initiates a call to a voice mailbox system 310, as
shown at process 720 of FIG. 7. The logic circuitry 14 retrieves the
telephone number of the voice mailbox system 310 and transmits a
conventional signal to the MTSO 12 requesting a connection to this
telephone number. If no voice channel is available, the logic circuitry 14
displays "ready" status and terminates the attempt to check the voice
mailbox system 310, as shown at decision point 725 of FIG. 7.
First Password Transmission
As shown at the process 730, upon acquisition of a voice channel, the logic
circuitry 14 waits a specified pause time, preferably preprogrammable,
then makes a DTMF transmission of a number corresponding to the password
that identifies a particular voice mailbox to the voice mailbox system
310. In other words, the logic circuitry waits for a time that should be
sufficient to allow the voice mailbox system 310 to "answer the phone,"
then sends the password of the voice mailbox associated with the telephone
unit 2 (e.g., the mailbox of the usual user of the phone) to the voice
mailbox system.
A number representing the pause time may be programmable (e.g., into a
specified location in the memory 16) by a user or by a technician, in
either case in a conventional manner, for retrieval by the logic circuitry
14 as part of the process 730. Equivalently, the pause time may be
hardwired or hardcoded into the logic circuitry 14; in some
implementations the relative lack of flexibility of such an approach might
be offset by other considerations (e.g., savings of hardware). It will
normally be preferred, however, that the pause time be programmable.
The logic circuitry 14 also retrieves the password from a suitable storage
location, e.g., a specified location in the memory 16. The password is
likewise preferably preprogrammable as just described above for the pause
time. In some implementations, the voice mailbox system 310 may be
designed so that the password of the voice mailbox associated with any
given telephone unit 2 is the same number as the mobile identification
code (MID) that uniquely identifies the telephone unit 2, in which case
retrieval of the password can be accomplished by retrieving the MID from
its own storage location. Equivalently but somewhat less flexibly, the
password may be hardwired or hardcoded into the logic circuitry 14.
The password is shown as being retrieved at process 730, but it will be
apparent to those of ordinary skill having the benefit of this disclosure
that this retrieval may take place at any time prior to the transmission
of the password to the voice mailbox system 310.
To promote the security of the password, the programming of the logic
circuitry 14 is preferably designed (in accordance with conventional
techniques) so that the contents of the memory location in which the
password is stored are not ordinarily accessible to a user and are
retrievable only by the logic circuitry 14 in connection with an automatic
voice mailbox check as described here.
Particular Embodiment for First Password Transmission
The telephone unit 2 may be equipped to handle indirect memory addressing
as described in my U.S. Pat. No. 4,875,230 entitled "Cellular Telephone
Unit Having Multiple Memory Location Command Language," Ser. No. 223,864,
filed June 25, 1988, assigned to the assignee of this application. Such an
implementation permits a particular approach to be used for storage and
retrieval of the voice mailbox telephone number and password.
In such an implementation the logic circuitry 14 is programmed to process
"recall" commands in a special manner. Briefly, any user memory location
(e.g., "speed dialing" memory locations) may be loaded with an arbitrary
sequence of recall commands that make reference to specific user memory
locations, pause commands, and other keystrokes such as numbers.
The logic circuitry 14 processes the contents of any such memory location
(referred to as a dialing sequence) as follows. Any recall command in the
dialing sequence is processed by substituting the contents of the
referenced user memory location for the recall command in a conventional
manner; in other words, each recall command is expanded as a macro. If a
referenced user memory location itself contains recall commands, those
commands are themselves expanded using conventional recursive or iterative
techniques. The fully-expanded dialing sequence will thus have no recall
commands, but instead will include the contents of all referenced user
memory locations.
Any keystrokes in a dialing sequence that occur prior to a first pause
command in the dialing sequence are treated as intended for processing on
the signalling channel during the initial signal exchange between the
telephone unit 2 and the MTSO 12. Keystrokes subsequent to the first pause
command (including subsequent pause commands) are treated as intended for
processing after acquisition of a voice channel. For example, the dialing
sequence "800-555-1212-P-12345-P-67890" (hyphens are inserted for clarity)
would result in transmission of "800-555-1212" over the signalling
channel, followed by "12345", a pause, and "67890" as DTMF tones over the
voice channel.
In such an implementation, the components of the dialing sequence (i.e.,
the telephone number of the voice mailbox system 310 and the password for
the voice mailbox in question) may be stored separately in a plurality of
user memory locations (the password possibly being stored in a restricted
location as described above). The dialing sequence itself can then be
represented in another user memory location as a combination of recall
commands and pause commands.
In particular, the dialing sequence may include (1) a recall command
referencing a user memory location containing the telephone number or
other access number of the voice mailbox system 310; (2) a first pause
command; (3) a recall conmmand referencing a user memory location
containing the password; and (4) a second pause command. Equivalently, the
entire dialing sequence may be stored in a single user memory location.
It will be apparent that the logic circuitry 14's processing of the dialing
sequence thus results in (1) transmission of the voice mailbox system
access number on the signalling channel; (2) pausing a sufficient length
of time to allow the voice mailbox system 310 to "answer the phone"; (3)
transmitting the password, e.g., in DTMF tones (which will be received and
presumably recognized by the voice mailbox system 310); and (4) pausing to
the extent of any optional second pause command.
Verification for Second Password Transmission
It has been noted that the voice mailbox system 310 is assumed to be
designed (per FIG. 3A) to require two transmissions of the password in
order to gain access to a mailbox, a first time (presumably automatically)
to identify the desired mailbox and a second time (manually) to
authenticate the caller's access authority. As shown in FIG. 8, the logic
circuitry 14 is programmed to provide additional password security in two
ways.
The first way relates to the situation in which the user of the telephone
user 2 does not enter any keystroke sequence at all, and a fortiori has
failed to enter a password (e.g., in response to the usual audio prompting
by the voice mailbox system 310). If (a) the user does not enter a
password within a specified time (decision box 825), and (b) a "nonnull"
password is found in the password storage (decision box 812), then (c) the
logic circuitry 14 terminates the call to the voice mailbox system 310
(process 840). If a "null" password is found in the password storage, on
the other hand (decision box 812), the logic circuitry 14 assumes that no
password is required and continues with the automatic voice mailbox check
as described below. A "null" password may be a blank memory, a pause
command, or other similar identifier.
The second way of providing additional password protection relates to the
situation in which a password is found in the password storage (decision
box 812), and the user enters a keystroke sequence (decision box 825), but
the keystroke sequence does not match the password. The logic circuitry 14
reads any manual keystrokes that may be entered during the automatic voice
mail check and compares them with any password that is stored in the
password storage (decision box 830). If (a) the keystrokes do not
correspond to the password itself, and (b) they do not correspond to a
command to recall a value (that itself proves to be equal to the password)
from user-programmable storage such as a location in the memory 16, then
(c) the call to the voice mailbox system 310 is terminated (process 840)
and the keystrokes are treated as a manual-override keystroke sequence and
processed as an ordinary user command, e.g., to dial a number (process
855).
If the correct password or password-recall command is timely entered by the
user, the logic circuitry 14 causes a DTMF transmission of the password
over the voice channel, presumably to the waiting voice mailbox system 310
(process 835). Keystrokes thereafter entered by the user are processed in
the normal manner; this is shown by process 855, but in some
implementations it may be preferable simply to terminate the voice mailbox
check routine at this point and return to normal operation for keystroke
processing.
Other Features
Other features may be added for the convenience of the user or for
security. For example, the logic circuitry 14 may be programmed to enable
an "in-use" display (such as the status light commonly provided on mobile
telephones) at a time, e.g., beginning when the telephone call to the
voice mailbox system 310 is initiated. As a security measure, the logic
circuitry 14 could be programmed to keep the speaker 6 silent until after
the first, automatic transmission of the password.
It will be appreciated by those skilled in the art having the benefit of
this disclosure that this invention is believed to be capable of
application in other situations in which the hardware and software work in
substantially the same way to achieve essentially the same result. Some of
these situations have been expressly described here (as examples and not
as limitations), and others will be recognized by those of skill.
Accordingly, this description is to be construed as illustrative only and
as for the purpose of teaching those skilled in the art the manner of
carrying out the invention.
It is also to be understood that various modifications and changes may be
made, e.g., in the shape, size, and arrangement of components, operating
steps, and so forth, without departing from the spirit and scope of the
invention as set forth below in the claims. It is intended that the
following claims be interpreted to embrace all such modifications and
changes.
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