Method and apparatus for preventing ambiguity in displaying the number of a recorded message that has been reached

A method and apparatus for indicating the number of the particular message that has been reached on a bi-directionally movable record medium used with a record/playback device. A position count is incremented and decremented as the record medium moves in forward and reverse directions, respectively; and end-of-message counts representing the locations of the ends of messages relative to an arbitrary reference location of the record medium are stored. Information representing the number of each message whose end-of-message count is stored is provided; and the number of the message which has been reached is determined as a function of which stored end-of-message count is greater than the present position count and which stored end-of-message count is less than that position count. To prevent ambiguities in determining the number of the message which has been reached, as when a new, partially used record medium is loaded into the record/playback device and is reversed to a location which precedes the reference location (i. e. the starting point of the record medium when it is loaded into the device), the position count is preset to a predetermined count when the record medium is replaced. This predetermined count is sufficient to prevent decrementing of the position count below zero, which would be interpreted as being greater than any of the stored end-of-message counts, even if the full amount of the newly-loaded record medium moves in the reverse direction.

BACKGROUND OF THE INVENTION 
This invention relates to a display for a record/playback device and, more 
particularly, to such a display which unambiguously indicates the number 
of the particular message that has been reached on a bi-directionally 
movable record medium. 
The invention disclosed herein is usable with and is an improvement of the 
invention described in copending application Ser. No. 564,480, filed Dec. 
21, 1983, U.S. Pat. No. 4,688,117 and assigned to the assignee of the 
present invention. As described therein, record/playback devices, such as 
dictation and/or transcription machines, provide indications of messages, 
such as letters, that have been recorded. Typically, a predetermined 
signal, such as a special tone signal, referred to generally as a "cue" 
tone, is recorded under the control of the machine user at the completion 
of each message or letter which he dictates. Such cue tones are utilized 
during transcription to control the energization of a light element 
display to apprise the transcriptionist of the relative locations and 
lengths of the respective messages, or letters, that have been dictated. 
Examples of light element displays of the aforementioned type are 
described generally in U.S. Pat. Nos. 4,051,540, 4,200,893 and 4,378,577. 
In addition to, or in place of, these light element displays, a numerical 
display may be provided to indicate the number of the particular message 
which has been dictated or which now is in position to be played back, as 
during transcription or during a review of previously dictated messages. 
One type of message-number display is described in copending application 
Ser. No. 564,480. There, when an end-of-message cue signal, referred to 
herein as a letter cue signal, is recorded, numerical information 
representing the number of messages that had been recorded up until then 
is updated. This numerical information is selectively accessed and 
displayed, thus indicating to the user the number of messages, or letters, 
which had been recorded previously. Thus, if the user has just completed 
recording message number 3, and has signified the end of that message by 
recording a letter cue signal, the display will indicate "3" when the 
message number information is accessed. As the user then records his 
fourth message, further access of the message number information will, 
nevertheless, result in the display "3". Of course, this numerical 
information is updated once the next (i.e. the fourth) letter cue signal 
is recorded. 
As also described in the aforementioned copending application, cue signals 
representing the location of dictated instructions also may be recorded on 
the record medium. These cue signals are referred to as instruction cue 
signals; and the numerical display may be selectively controlled to 
indicate to the user the number of instructions which have been recorded. 
Thus, the display control arrangement is provided with means for storing 
numerical information representing the number of messages that have been 
recorded as well as means for storing numerical information representing 
the number of instructions that have been recorded. Each type of numerical 
information may be selectively accessed and displayed. 
In the display described in the aforementioned application, a position 
counter is incremented and decremented as the record medium (which, 
typically, is a magnetic tape) moves in the forward and reverse 
directions, respectively. Cooperating with the record medium transport 
apparatus is a pulse generator which supplies pulses to a counter that 
provides a position count representing the position of the record medium 
relative to a reference location. As an example, if the record medium is a 
magnetic tape bi-directionally driven between supply and take-up reels, a 
so-called chopper wheel mechanically coupled to the supply reel generates 
pulses at a rate corresponding to the rotary speed of that supply reel. 
Hence, the position count is obtained simply by counting the chopper 
pulses. When a letter cue signal is recorded, the count then present in 
the position counter is stored at an addressed location in a memory; and 
each address is used as the aforementioned numerical information 
representing the number of the message that had just been recorded. When 
the tape is rewound, for example, the position counter is decremented; and 
when the position count is decremented to a count equal to a stored 
end-of-message count, the address at which that end-of-message count is 
stored is utilized to display the number of the letter which has been 
reached. 
Similarly, when an instruction cue signal is recorded, the count of the 
position counter is stored as an instruction count at an addressed memory 
location, and the address of that location is used to display the number 
of the instruction which has been recorded. When the tape is moved to a 
position at which the instruction cue signal is recorded, the address at 
which the instruction count is stored is used to display the number of the 
instruction which has been reached. 
It had been thought preferable to reset the aforementioned position counter 
each time a fresh record medium (e.g. a fresh tape cassette) is loaded 
into the dictation/transcription machine. By resetting the position 
counter, the position count then will be incremented from a reference 
[0000] count as the record medium advances for the purpose of dictation. 
Such resetting of the position count to [0000] presents no problem if the 
tape included in the freshly loaded cassette is fully rewound. That is, if 
the reference location of the newly-loaded tape corresponds to the very 
beginning thereof, the position counter merely will increment from its 
[0000] count and, since the tape cannot be rewound further, the counter 
cannot be decremented below its [0000] count. 
However, ambiguity is introduced into the aforementioned message number 
display if the fresh cassette that is loaded into the 
dictation/transcription machine initially is positioned at some arbitrary 
reference location. That is, if the tape therein is not fully rewound, the 
resetting of the position counter to [0000] does not represent the 
beginning of the tape. The user may dictate one or more messages on the 
newly-loaded tape, resulting in the storage of end-of-message counts and 
the provision of numerical information representing the number of each 
recorded message, as in the manner mentioned above and as more fully 
disclosed in the aforementioned patent application. As the tape is 
reversed, the position counter is decremented; and when the position count 
becomes equal to a stored end-of-message count, the address at which that 
end-of-message count is stored is used to display the number of the letter 
that has been reached. It is possible, however, that the user may rewind 
the tape beyond the arbitrary reference location thereof, that is, beyond 
the starting point at which dictation commenced. The position counter then 
will be decremented below its [0000] count which, as is typical, results 
in a "roll over" of the count to a maximum value, such as [9999]. Further 
reversal of the tape results in further decementing of the position count 
from [9999] towards a lower value. 
A technique that can be used for displaying the number of the message that 
has been reached on the tape is based upon a comparison of the position 
count to the stored end-of-message counts. If the position count is 
greater than one stored end-of-message count but is less than another, the 
number of the message which has been reached, that is, the number of the 
message then juxtaposed the record/playback transducer of the 
dictation/transcription machine, is the number associated with the larger 
end-of-message count (i.e. the number of the message is equal to, or 
derived from, the address at which the larger end-of-message count is 
stored). Alternatively, the number of the message which is displayed may 
be equal to the number that is associated with the smaller stored 
end-of-message counts plus one (i.e. the displayed message number is equal 
to 1 plus the address of the location at which the smaller end-of-message 
count is stored). 
An example of the aforementioned technique for determining the number of 
the message which has been reached is best understood from a numerical 
example. Let it be assumed that the tape included in a newly-loaded 
cassette has not been fully rewound but, nevertheless, the position count 
is reset to [0000]. Let it be further assumed that a first letter cue 
signal is recorded at a location corresponding to a position count of 
[950], a second letter cue signal is recorded at a location corresponding 
to a count of [1140], and the user presently is in the process of 
dictating a third message. The position count will be greater than [1140] 
and, consequently, the message number display, when accessed, will 
indicate to the user that the tape presently is at a location 
corresponding to letter "3". This is because the position count is greater 
than the last-stored end-of-message count [1140], and this stored 
end-of-message count is associated with letter "2". Now, if the tape is 
rewound such that the position count is decremented to a count less than 
[1140] but greater than a count of [950], the message number display will 
indicate that the tape has reached letter "2". With further reverse 
movement of the tape, the position count continues to decrement; and when 
this count becomes less than [950], the message number "1" is displayed, 
indicating that the first message which had been dictated on the tape has 
been reached and is juxtaposed the record/playback transducer. Now, if the 
tape is further rewound to a location which precedes the reference 
location, that is, if the tape is rewound beyond its starting point, the 
position count is decremented below [0000] and "rolls over" to a count of 
[9999]. This count is greater than the largest stored end-of-message count 
[1140] and, thus, the message number which is displayed is message number 
"3". Thus, the user is erroneously apprised that the third message (which 
he had been in the process of dictating) has been reached. 
The foregoing explains the ambiguity which may occur when the position 
count normally is reset to a zero count [0000] when a cassette is 
replaced, and the new cassette has not been fully rewound prior to 
resetting the position count. This ambiguity may erroneously indicate to 
the user that a particular message recorded on the tape has been reached 
when, in fact, the tape actually is nowhere near that message. 
OBJECTS OF THE INVENTION 
Therefore, it is an object of the present invention to provide an improved 
display which overcomes the aforenoted disadvantages and which 
unambiguously indicates the actual number of the particular message that 
has been reached on a record medium. 
Another object of this invention is to provide a message number display for 
unambiguously indicating the number of the recorded message which is 
juxtaposed the transducer of a record/playback device. 
A further object of this invention is to provide a method and apparatus for 
controlling a message number display of a record/playback device operable 
with a bi-directionally movable record medium, even if that medium is not 
initially positioned at its beginning location when loaded into the 
record/playback device. 
An additional object of this invention is to provide a method and apparatus 
for controlling a position counter such that it is constrained from 
providing counts resulting in ambiguous indications of the number of the 
message that has been reached on a record medium in a device of the 
aforementioned type. 
Various other objects, advantages and features of the present invention 
will become readily apparent from the ensuing detailed description, and 
the novel features will be particularly pointed out in the appended 
claims. 
SUMMARY OF THE INVENTION 
In accordance with this invention, a method and apparatus are provided for 
unambiguously indicating the number of the particular message recorded on 
a bi-directionally movable record medium that is juxtaposed the transducer 
of a record/playback device. A position count is incremented and 
decremented as the record medium moves in forward and reverse directions, 
respectively, and end-of-message counts representing the location of the 
end of a message relative to an arbitrary reference location of the record 
medium, and derived from the position count, are stored. Information 
representing the number of each message whose end-of-message count is 
stored also is provided. The number of the message juxtaposed the 
transducer is determined as a function of which stored end-of-message 
count is greater than the position count and which stored end-of-message 
count is less than the position count. When the record medium used by the 
device is replaced, the position count is preset to a predetermined count 
such that, regardless of the arbitrary reference location of a new record 
medium that is loaded into the device, the position count will not be 
decremented below a count of zero when the record medium moves in the 
reverse direction to a location that precedes the reference location. 
As a feature of this invention, the predetermined count to which the 
position count is preset is at least equal to the maximum position count 
that can be obtained if the record medium is advanced from its very 
beginning to its very end. 
Preferably, the record medium comprises a fixed length of magnetic tape 
housed in a cassette and transported between supply and take-up reels. 
It is a desirable feature of this invention to prevent the position count 
from being decremented below a zero count, which otherwise would result in 
a "rolled over" count that would be greater than any stored end-of-message 
count and that would result in an erroneous indication of the number of 
the message juxtaposed the transducer of the record/playback device (e.g. 
if n messages have been recorded, an erroneous indication that message 
number "n+1" is juxtaposed the transducer).

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
The present invention, to be described, is particularly adapted for use in 
a portable, battery-operated dictate device, although so-called desk-top 
dictation/transcription devices may be used with this invention. However, 
as will be apparent, this invention is equally applicable to a sound 
recorder that may be used for other applications and need not be limited 
solely for use as a dictate machine. The record/playback device described 
herein preferably is used with a miniature, thumb-sized, capstan-driven 
magnetic tape cassette, such as the tape cassette described in U.S. Pat. 
Nos. 4,476,510 and 4,443,827. However, it should be readily appreciated 
that, if desired, the record/playback device described herein need not be 
limited solely for use with magnetic tape cassettes but, rather, may be 
used with other record media, such as magnetic discs which may be 
rotatably driven and may be selectively engaged by a magnetic head that is 
moved in the forward and reverse directions. Also, the record medium may 
comprise a bubble-memory device wherein forward and reverse "movements" 
are simulated by forward and reverse shifting of "bubbles" which, as is 
known, represent information. Similarly, the record medium may comprise a 
solid state memory "chip" wherein movements are simulated by shifting the 
addresses of locations in which digitized information is written and read. 
As used herein, the expression "movable record medium" is intended to 
include the foregoing media and other analogous media for 
recording/reproducing or storing/reading information. 
For convenience, the record/playback device is described herein in the 
context of a portable, battery-operated dictate machine. As shown in FIG. 
1, device 10 is provided with a plurality of manually operable controls, 
plural displays, a microphone 12 (illustrated, as an example, at the upper 
right-hand corner of the device) and a speaker 52. In one embodiment, the 
manually operable controls comprise push-button elements, each being 
selectively operable to control or initiate a corresponding function. 
Alternatively, these controls may be formed as touch-sensitive switches 
adapted to produce signals representing the actuation thereof when touched 
by the user of the device. In either embodiment, a respective signal is 
produced in response to the operation of a corresponding control element, 
and this signal is produced for so long as that element is operated. Upon 
release of the element, the signal terminates. Suitable push-buttons, 
switches and the like for providing these functions are conventional and 
are well known. 
The displays, identified as displays 40, preferably are formed as LCD 
display devices which, as is conventional, require relatively little 
electrical energy to provide suitable indications; and, thus, 
advantageously impose little drain on the electrical storage battery which 
is used to energize device 10. Alternatively, other visual indicator 
display devices, such as LED devices, electroluminescent devices, and the 
like may be used to implement display 40. 
Although not shown in FIG. 1, it will be appreciated that, in the 
embodiment described herein, device 10 is operable with a removable record 
medium. As mentioned above, this record medium preferably comprises a 
miniature, thumb-sized tape cassette. On the reverse, or backside of 
device 10 (not shown) there is provided a door to a cassette-receiving 
compartment in which the cassette is contained for operation. A suitable 
switch (also not shown) may be coupled to this door or may be contacted by 
a cassette loaded into the cassette compartment so as to produce a 
suitable signal when the cassette is removed. As an alternative, this 
signal may be produced when a fresh cassette is loaded into the 
compartment. As will be described, this signal functions as a "preset" 
signal. 
The manual controls provided with record/playback device 10 include various 
switches, such as pushbutton switches which, for convenience, are referred 
to merely as buttons. These buttons include a conference record button 22, 
a momentary record button 24, a stop button 26, a rewind/play button 28, a 
cue/erase button 30, a reset/mode button 32, a fast forward button 34 and 
a keyboard enable button 36. For convenience, these elements are referred 
to merely as buttons. In addition, a volume adjustment control knob 38, 
such as a potentiometer, also is provided. 
Conference record button 22 and momentary record button 24 are manually 
operable to dispose record/playback device 10 in the so-called "conference 
record" and "momentary record" modes of operation, respectively. When 
disposed in the conference record mode, the gain in the recording 
electronics is increased such that device 10 can be used to record a 
"conference" among individuals who are disposed at some distance from 
microphone 12. In the momentary record mode, the gain of the recording 
electronics is reduced, thus making the pick-up sensitivity of the device 
less sensitive. In the momentary record mode, it is expected that the user 
will hold device 10 in close proximity to his mouth. With reduced pick-up 
sensitivity, ambient noises will not be recorded and, thus, such noises 
will not interfere with the user's dictation. Furthermore, the operation 
of record button 24 establishes the momentary record mode for so long as 
this button is operated. Upon release of the record button, the mode of 
device 10 is changed over to an inactive, or stop, mode. However, when 
conference record button 22 is operated, the conference record mode is 
established, and this mode remains "latched" even when the conference 
record button is released. 
Rewind/play button 28 is adapted, when operated, to dispose device 10 in a 
rewind mode, whereby the magnetic tape is driven in the reverse direction 
at a relatively high rate of speed. Upon release of button 28, the 
direction in which the tape is driven is reversed, and the rate at which 
the tape now is moved in the forward direction is reduced to the speed at 
which information can be played back. It is appreciated that this speed is 
equal to the speed at which the tape is driven when either conference 
record button 22 or momentary record button 24 is operated. Stop button 
26, when operated, functions to change over device 10 from an active mode 
(e.g. record, play, etc.) to an inactive, or stop mode. It is appreciated 
that, in this inactive or stop mode, the tape is maintained stationary. 
Cue/erase button 30 is adapted, when operated momentarily, to record a 
"cue" signal on the magnetic tape and, additionally, to provide a cue 
indication which represents the location along the tape at which the cue 
signal is recorded. This cue indication enables the user to rapidly move 
the tape in either the rewind or fast forward modes to the location at 
which that cue signal is recorded. Preferably, cue indications 
representing "letter" and "instruction" cues, respectively, may be 
recorded by selectively operating the cue button. For example, the 
"letter" cue indication is provided, and a corresponding "letter" cue 
signal is recorded, upon a single momentary operation of cue button 30. 
This designates the end of a letter, or message, or segment of dictation, 
that has been recorded. Upon a repeated momentary operation of the cue 
button within a predetermined time period, for example, if the cue button 
is operated twice within a period of 1 second, an "instruction" cue is 
indicated and recorded to designate the location of a recorded 
instruction. 
As will be described below, display 40 includes a plural-digit (e.g. a 
3-digit) numerical display 42 which normally functions as a tape counter 
to provide a numerical indication of the amount of tape which has been 
transported, thereby representing the present position of the tape. 
Reset/mode button 32 is adapted, when operated or pushed for a prolonged 
period of time, to reset numerical display 42. When the reset/mode button 
is operated momentarily, the information displayed by numerical display 42 
is changed over, or toggled, to display the number of the letter, or 
message that has been recorded, and/or the number of the particular letter 
or message which is in position to be (or is in the process of being) 
played back. Also, if device 10 is in its record or fast forward or rewind 
mode, numerical display 42 displays the number of the instruction that has 
been recorded or that has been reached, respectively. 
Fast forward button 34, when operated, functions to dispose device 10 in 
its fast forward mode in which the magnetic tape is transported at a 
relatively rapid speed in the forward direction. In this mode, when the 
tape has been transported to the end of a letter (or message) or to a 
location at which an instruction had been recorded, the tape transport 
provided in device 10 is temporarily interrupted so as to "pause" at that 
location and the number of the next letter or of the instruction which has 
been reached is displayed. Hence, the tape may be rapidly transported to 
the beginning of a letter or an instruction. Similarly, the tape may be 
rapidly transported in the reverse direction to a letter or instruction 
upon the operation of rewind/play button 28. That is, when device 10 is 
disposed in the rewind mode of operation, the tape is rapidly rewound 
until the end of a letter (or message) or the location at which an 
instruction had been recorded is reached, whereupon the tape transport 
"pauses" thereat and the number of the next letter or of the instruction 
is displayed. 
Enable button 36 functions in a manner analogous to a POWER ON switch. 
Device 10 is provided with a programmed microprocessor which is responsive 
to the selective actuation of the illustrated control buttons to control 
both the operation of the device and the information displayed by display 
40. The manner in which this microprocessor operates is described in 
detail in copending application Ser. No. 564,480. When not in use, device 
10 and the microprocessor therein are disposed in a dormant, or 
non-operating condition. When the device is to be operated by the user, 
enable button 36 is operated so as to change over the device from its 
dormant condition to an inactive mode, thus awaiting subsequent actuation 
of a control button. As will be described below, when device 10 is 
disposed in its inactive mode, which corresponds to a "stop" mode, both 
the device and the microprocessor will change over to the dormant 
condition automatically if no active mode is initiated within a 
predetermined time period. Stated otherwise, when the device is disposed 
in its stop mode, it will revert to its dormant condition unless 
conference record button 22, momentary record button 24, rewind/play 
button 28 or fast forward button 34 is operated within the aforementioned 
time period. The operation of enable button 36 will bring the 
microprocessor out of the dormant condition. 
As mentioned above, display 40 is provided with a plural-digit numerical 
display 42. As one example thereof, numerical display 42 may be comprised 
of a 3-digit display, each digit being represented by a 7-segment LCD 
element or other conventional visual indication numerical display device. 
This numerical display is adapted to be incremented and decremented as the 
tape is driven so as to provide a numerical indication of the amount of 
tape which has been transported. 
Display 40 also is provided with a bar graph, or index, display 44, a 
"record/play" indicator 46, and a "letter/instruction" indicator 48. Bar 
graph display 44 is comprised of a plurality of individual elements or 
segments, such as LCD segments, which are adapted to be selectively 
energized to provide an indication of the approximate quantity of tape 
which has been transported, thereby providing a bar graph display of the 
present position of the tape. As an example, if bar graph display 44 is 
formed of ten segments, each segment may represent approximately 10% of 
the overall length of tape; and as successive tape is transported in the 
forward direction, additional ones of segments 44 are energized. 
Preferably, the segments which comprise the bar graph display are 
selectively energized to provide a left-to-right shifting effect when 
device 10 is disposed in the fast forward mode; and these segments are 
energized to provide a right-to-left shifting effect when the device is 
disposed in its rewind mode. 
"Record/play" indicator 46 is adapted to be energized to display REC when 
device 10 is disposed in its record mode and to display PLAY when the 
device is disposed in its playback mode. This provides the user with an 
indication of the particular mode of operation in which the device is 
disposed. "Letter/instruction" indicator 48 is adapted to display LTR when 
a letter cue signal is recorded and to display INS when an instruction cue 
signal is recorded. Also, upon the momentary operation of reset/mode 
button 32, the indication LTR is displayed together with a numerical 
indication by display 42 to indicate the number of the particular letter 
then juxtaposed the record/playback head of device 10. Additionally, when 
the record medium with which device 10 is used is rewound or advanced 
rapidly to the end of a previously recorded letter, or to a previously 
recorded instruction, the indication LTR or INS, respectively, and the 
number of that letter or instruction which has been accessed are 
displayed. 
In the preferred embodiment, the record medium which is used with device 10 
is a capstan-driven cassette having a magnetic tape which extends between 
supply and take-up reels. A single, bi-directional two-speed motor is 
provided to drive the capstan and, also, to drive supply and take-up reel 
spindles, respectively. A relatively simple transmission, such as a 
belt-drive, is used to couple the motor to the capstan and also to the 
supply and take-up reel spindles. Preferably, suitable clutches are 
provided in the spindles to permit the tape to be bi-directionally driven 
between the reels. 
A pinch roller is mounted on a movable device, referred to herein as an 
actuator, in a manner similar to that described in U.S. Pat. No. 
4,547,821. During record and play modes of operation, the actuator is 
energized such that the pinch roller fully engages the capstan, thereby 
"pinching" the tape therebetween. The capstan is driven by energizing the 
motor in the forward direction, thereby transporting the tape from the 
supply reel to the take-up reel. A suitable record/playback head also is 
mounted on the actuator so as to be in good magnetic contact with the tape 
when the pinch roller is engaged. Consequently, information may be 
recorded on or played back from the tape by this head. 
As described in copending application Ser. No. 564,480, when letter cue 
signals are recorded, the instantaneous count of the tape counter, also 
referred to herein as a position counter, is stored in an addressed 
location of a letter cue memory. As a simplified example, the position 
count is stored in the first addressable location of the letter cue memory 
when the first letter cue signal is recorded, thus resulting in the 
storage of an end-of-message count which represents the location of the 
end of the first message. After the user completes his dictation of the 
second message, another letter cue signal is recorded; and the position 
count is stored as an end-of-message count in the second addressable 
location of the letter cue memory. A similar operation is carried out for 
the third, fourth, and other end-of-message counts. Thus, the particular 
address at which an end-of-message count is stored represents the number 
of the message associated with that stored end-of-message count. 
A schematic representation of a letter cue memory 14 in which are stored 
five separate end-of-message counts is illustrated in FIG. 2. As a 
numerical example, position count [950] is stored at address 1, position 
count [1140] is stored at address 2, and so on, as illustrated. 
As will be explained, the letter cue memory location addresses serve as 
information representing the number of the message whose end-of-message 
count is stored at that address. This information, the memory location 
address, is used to display the number of the message then juxtaposed the 
transducer of the record/playback device, that is, the number of the 
message that has been reached. One technique for displaying the number of 
the message that has been reached is described in copending application 
Ser. No. 564,480. Another technique that can be used to display the number 
of the message that has been reached is based upon a determination of 
which stored end-of-message count is less than the instantaneous position 
count and which stored end-of-message count is greater than that position 
count. If the position count is represented as x, then the end-of-message 
counts that are stored in the respective cue memory addresses are read 
out, in sequence, and each end-of-message count is compared to position 
count x. When it is determined that x is greater than the end-of-message 
count read out of one address location but is less than the end-of-message 
count read out from the next address location, it is concluded that the 
number of the message then juxtaposed the transducer is the message 
associated with the larger end-of-message count. The address at which is 
stored this larger end-of-message count is displayed as the number of the 
message that has been reached. 
As an alternative, the difference between x and each stored end-of-message 
count that is greater than x is sensed, and the address at which is stored 
the end-of-message count having the smallest difference is used to 
indicate the number of the message that has been reached. 
As yet another alternative, each stored end-of-message count is read out 
from letter cue memory 14 and is compared to x. The address of the memory 
location at which is stored the last end-of-message count that is less 
than x is incremented by 1 and used to display the number of the message 
that has been reached. 
In accordance with any of the foregoing alternatives, if it is assumed that 
x equals [1400], this position count is compared to each of the 
end-of-message counts stored in letter cue memory 14. It is seen that, in 
accordance with this example, x is greater than the end-of-message count 
stored at address 3, but x is less than the end-of-message count stored at 
address 4. Hence, it is concluded that some portion of message "4" is 
juxtaposed the transducer, and address "4" is displayed as the number of 
the message which has been reached. 
FIG. 3 is a schematic representation of a length of magnetic tape 20 upon 
which five messages have been recorded with letter cue signals designating 
the ends of those messages recorded at locations corresponding to position 
counts [950], [1140], [1375], [1590] and [1750], consistent with the 
schematic representation of the letter cue memory of FIG. 2. It is, of 
course, recognized that the position count may be an actual count that is 
obtained by a counter which counts chopper pulses that are generated as 
magnetic tape 20 is driven, and as described more particularly in 
copending application Ser. No. 564,480. 
Normally, when a cassette is removed from the record/playback device or 
when a fresh cassette is loaded thereinto, the tape position counter is 
reset to an initial count [0000]. This automatic resetting may be achieved 
by a suitable switch that is opened upon the removal of the cassette or 
that is closed upon the insertion of a fresh cassette. Although no 
ambiguity in the number of the message that is displayed will occur if the 
position counter is reset to [0000] at the very beginning of the magnetic 
tape, that is, if the tape of a fresh cassette is fully rewound before 
being loaded into the device, ambiguity may result in the display of the 
message number if magnetic tape 20 has been partially rewound, or 
partially used, prior to its loading into the record/playback device. Let 
it be assumed that, as shown in FIG. 3, an arbitrary reference location is 
assumed by the magnetic tape at the time that it is loaded into the 
device. Hence, although a portion of the tape already has been transported 
from its supply reel to its take-up reel, the position counter 
nevertheless is reset to a count of [0000] when the cassette is loaded 
into the device, this count identifying the reference location of the 
magnetic tape, as illustrated in FIG. 3. Let it be further assumed that 
tape 20 is transported in the usual manner, and that letter cue signals 
are recorded at locations represented by end-of-message counts [950], 
[1140], and so on, as is also illustrated. 
So long as magnetic tape 20 is not rewound to a location that precedes 
reference location [0000], a proper display of the message then juxtaposed 
the transducer will be provided, as discussed above. However, if tape 20 
is rewound sufficiently, the position count will decrement to the count 
[0000] and then will reach the count [9999] from which it will be further 
decremented. Thus, after passing beyond the reference location of tape 20, 
the instantaneous count of the position counter will exceed the maximum 
end-of-message count that is stored in letter cue memory 14. When this 
greater position count is compared to the end-of-message counts read out 
from the letter cue memory, the message number determining operation will 
erroneously conclude that the tape is at some position downstream of the 
location corresponding to end-of-message count [1750], and it will 
conclude that message "6" has been reached. Thus, even though the tape 
merely has been rewound to a location that precedes the reference 
location, the message number display, if accessed, will indicate that 
message "6" is juxtaposed the transducer. 
The foregoing ambiguity is removed by the present invention in which, 
rather than reset the position counter to the count [0000] when a cassette 
is replaced (i.e. when a previously used cassette is removed or when a 
fresh cassette is loaded), the present invention proceeds by presetting 
the position count to a predetermined count which cannot be decremented to 
[0000] even if the entire length of tape 20 is rewound. Thus, if tape 20 
had been fully wound onto the take-up reel at the time it is loaded into 
the record/playback device, thus requiring the full length of tape to be 
rewound, the preset position counter, although decremented, will not be 
decremented below the count [0000]. Hence, the position count will not 
"roll over"; and an ambiguous indication of the number of the message that 
has been reached on tape 20 will not occur. 
Before describing the manner in which the microprocessor that is used with 
display 40 operates, reference is made to FIGS. 4 and 5 which 
schematically represent other embodiments of a letter cue memory 16 or a 
letter/instruction cue memory 18. In the FIG. 4 embodiment, in addition to 
storing each end-of-message count at a respective addressed location, the 
number of the message whose end is represented by the stored count also is 
stored in the same (or associated) memory address. Thus, when an 
end-of-message count is read out from memory 16, the number of the letter 
associated with that count also is read out. When using the embodiment of 
FIG. 4, the read-out message number (referred to as a letter count) may be 
used in place of the memory address to indicate the number of the message 
that has been reached. The schematic illustration in FIG. 5 of cue memory 
18 is similar to that shown in FIG. 4, except that in the FIG. 5 
embodiment each addressable location stores, in addition to a tape count, 
the number of the message or instruction that is associated with that tape 
count. For example, in the first addressable location of cue memory 18, 
the end-of-message count [950] is stored, together with a letter count 
18L.sub.1 which, in this example, represents that the end of the first 
message is recorded at position [950]. Similarly, in the second 
addressable location of cue memory 18 is stored the count [1140] together 
with a letter count 18L.sub.2. This letter count 18L.sub.2 represents that 
the end of the second message (or letter) is recorded at position count 
[1140]. 
The count [1250] is stored at the third addressable location of cue memory 
18, and this position count is associated with an instruction count 
18I.sub.1 which represents that the first instruction is recorded at 
position [1250]. 
In similar manner, letter count 18L.sub.3 is stored at the same address as 
position count [1375], representing that the end of the third message is 
recorded at this position; and instruction 18I.sub.2 is recorded at the 
same address as position count [1450], representing that this is the 
location at which the second instruction is recorded. Alternatively, the 
letter or instruction counts may be stored at addresses which are 
associated (e.g. linked) with the addresses at which the position counts 
are stored. When the embodiment shown in FIG. 5 is used, the number of the 
message that is associated with a stored end-of-message count or, 
alternatively, the number of an instruction that is associated with a 
stored position count, is read out and used to display the number of the 
message (or letter) or the number of the instruction that has been 
reached. It is appreciated that the number of the message or instruction 
is determined as a function of the comparison between the instantaneous 
position count and the counts stored in cue memory 18. If one 
end-of-message count is greater than the instantaneous position count and 
the next successive end-of-message is less than the position count, the 
message number associated with the greater end-of-message count is 
utilized to indicate the number of the message which has been reached. 
Turning now to the flow chart shown in FIG. 6, it will be appreciated that 
only the relevant portion of the overall program of the microprocessor is 
described. This microprocessor may be similar to the one described in 
copending application Ser. No. 564,480, and the overall program thereof 
may be similar to that shown in FIG. 2 of that application. This overall 
program is referred to in FIG. 6 as main loop 60. FIG. 6 also illustrates 
the routine that, for example, may be entered from the main loop, this 
routine serving to avoid ambiguities in determining the particular number 
of the message which is juxtaposed the record/playback transducer. The 
routine shown by the flow chart in FIG. 6 may be executed periodically, 
for example, once during each cycle of main loop 60, or the routine may be 
executed more or less often, as may be desired. The periodicity of the 
execution of this routine need not be dependent or contingent upon the 
occurrence of other events but, rather, may simply be designed into the 
microprocessor program. 
In the routine shown in FIG. 6, inquiry 62 first is made as to whether a 
cassette (or other record medium) has been removed from the 
record/playback device. If this inquiry is answered in the affirmative, 
the routine advances to instruction 64 whereat the position counter is 
preset to a predetermined count. As one numerical example, if the 
record/playback device is used with a cassette having a fixed length of 
tape on which thirty minutes of dictation may be recorded, it is expected 
that less than 2,048 chopper pulses will be generated if the entire length 
of tape is transported. Thus, by presetting the position counter to a 
count of [2048], it is recognized that, even if the entire length of tape 
is rewound, the position counter will not be decremented below the count 
[0000]. It is to be noted here that the position counter should have a 
counting capacity sufficient to be incremented to a count of [4096]. More 
generally, the position counter should be able to be incremented to a 
count that is twice the preset count. Hence, if a fresh cassette happens 
to be fully rewound before being loaded into the device, the counter can 
be incremented from its preset count to a count of, for example [4096], or 
twice the preset count, when the entire length of tape is transported. 
After presetting the position counter, or if inquiry 62 is answered in the 
negative, the routine advances to inquiry 66 to determine if a chopper 
pulse transition has occurred. A chopper pulse transition is represented 
as a transition from a binary "1" level to a binary "0", or vice versa, in 
the voltage output generated from the chopper wheel that, as described 
above, preferably is mechanically coupled to the supply reel drive spindle 
of the record/playback device. If a chopper pulse transition has not 
occurred, the routine returns to main loop 60. However, if a chopper pulse 
transition is present, the routine advances to inquiry 68 to determine if 
the tape is transported in the forward or reverse direction. 
If tape is being transported in the forward direction, the position counter 
is incremented, as at 70; and this position counter is decremented, as at 
72, if tape is being transported in the reverse direction. After the 
counter is incremented or decremented, the routine advances to instruction 
74 (which may comprise a set of instructions), whereat the position count 
is compared to the end-of-message counts stored in the cue memory, as 
discussed above. Then, depending upon which end-of-message count is 
greater than the position count and which end-of-message count is less 
than the position count, the appropriate number of the letter that has 
been reached is displayed, as at 76. The routine then returns to main loop 
60. 
It is recognized that the position counter is preset to the predetermined 
count of, for example, 2,048 (or greater), when a cassette has been 
removed from the record/playback device. If a cassette has not been 
removed, this preset operation is not carried out. As an alternative, the 
position counter may be preset to the predetermined count when a fresh 
cassette is loaded into the device. In either embodiment, it is sufficient 
if the position counter is preset to the predetermined count before any 
forward movement of tape is initiated. It is appreciated, therefore, that 
other means may be used to preset the position counter accordingly. 
Although conventional switches or other sensing devices responsive to the 
removal or insertion of a cassette may be relied upon, other means, such 
as a forward movement sensor, a sensor responsive to the first chopper 
pulse generated when tape moves in the forward direction, a sensor 
responsive to a control button which commands forward tape movement, or 
the like, may be used. 
While the present invention has been particularly shown and described with 
reference to a preferred embodiment, it will be readily appreciated that 
various changes and modifications may be made without departing from the 
spirit and scope of the invention. For example, other record media may be 
used with this invention, such as a magnetic disk, a bubble memory, a 
solid-state semiconductor memory, or the like. Also, the position counter 
may be preset to any desired count, provided that this count will not be 
decremented below a zero count if the entire length of record medium is 
rewound. Further, any suitable means, such as, but not limited to, those 
described above may be used to preset the position counter, as when the 
record medium is removed from or loaded into the record/playback device, 
or at any other suitable time. While this careful preset operation 
preferably should be carried out automatically, manual means may be 
provided for presetting the counter, such as, in addition to those 
described above, the manual operation of the enable button. 
It is intended that the appended claims be interpreted as including the 
foregoing as well as other changes and modifications.