U.S. patent number RE32,365 [Application Number 06/568,549] was granted by the patent office on 1987-03-03 for precessing display pager.
This patent grant is currently assigned to Sanders Associates, Inc.. Invention is credited to George Sebestyn.
United States Patent |
RE32,365 |
Sebestyn |
March 3, 1987 |
Precessing display pager
Abstract
A hand held paper pager is disclosed in which a transmitted
message is displayed in alpha/numeric form by a precessing display
which moves the received message across the display in a continuous
fashion so that the display need be only large enough to present a
relatively small portion of the total message at any given time. In
one embodiment a dot matrix LED display is used and is driven by a
recirculating shift register memory to provide the precession of
the message as a result of the recirculation. In another embodiment
the pager may also include a message entry section in which the
precessing display is used to present and edit the message prior to
transmission either via an acoustic telephone link to a remote
transmitter, or directly from a transmitter carried in the
pager/encoder package.
Inventors: |
Sebestyn; George (Weston,
MA) |
Assignee: |
Sanders Associates, Inc.
(Nashua, NH)
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Family
ID: |
27074820 |
Appl.
No.: |
06/568,549 |
Filed: |
January 5, 1984 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
580075 |
May 22, 1975 |
03976995 |
Aug 24, 1976 |
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Current U.S.
Class: |
340/7.21;
340/7.52; 341/27; 345/169; 345/82 |
Current CPC
Class: |
G09G
3/14 (20130101); G08B 5/226 (20130101) |
Current International
Class: |
G08B
5/22 (20060101); G09G 3/14 (20060101); G09G
3/04 (20060101); G09G 003/00 (); H04B 001/00 () |
Field of
Search: |
;340/311.1,792,791,365R
;178/4.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Electroluminescent Typewriter; Hamburger N.E.C.; vol. 15, pp.
575-584; 1959. .
"Personal Signaling, A New Telephone Service"-Newton Monk, et al,
In 1958 Ire Weston Convention Record, part 8, pp. 76-79, 82-83.
.
Comparison of Mobile Radio Transmission at 150, 450, 900 & 3700
Mc, W. Rae Young, Jr., In The Bell Systems Technical Journal, vol.
32, Nov. 1952, pp. 1068-1085. .
"Radio Transmission into Buildings at 35 and 150 mc" by L. P. Rice,
In The Bell Systems Technical Journal, vol. 38, Jan. 1959, pp.
197-210. .
"A Complete Interactive Terminal You Can Hold in One Hand", Modern
Data; Apr. 1974; pp. 34-36..
|
Primary Examiner: Curtis; Marshall M.
Attorney, Agent or Firm: Etlinger; Louis Weinstein; Stanton
D.
Claims
I claim:
1. A pager for displaying a message in alpha/numeric form
comprising:
means for receiving address signals and coded message signals;
means for decoding said address .[.-.]. signals and for generating
an actuation signal;
an internal memory for storing received message signals;
means for displaying an alpha/numeric message of a predetermined
length.Iadd., .Iaddend.said display .Iadd.means .Iaddend.having
character display means at different lateral locations;
means responsive to said actuation signal for loading said message
signals into said memory; and
means for reading out said memory, decoding the signals read out
from said memory and for driving said display means with the
decoded message in such a manner that said message precesses across
said display by lateral displacement of a character in the message
a number of times to next adjacent character locations.[.,.]. so
that the character moves across the display from one side of the
display to the other side, whereby long messages for a
predetermined recipient may be displayed on a limited length
display in a personally portable unit.
2. The pager of claim 1 wherein said memory is a recirculating
memory which recirculates to precess the message.
3. The pager of claim 2 wherein said recirculating memory includes
a shift register and means for advancing said shift register.
4. The pager of claim 3 wherein said pager includes means for
freezing the precession and wherein said advancing means
selectively advances said shift register continuously and a
character at a time.
5. The pager of claim 1 wherein said display includes a number of
light emitting diodes for defining the alpha/numeric character.
6. The pager of claim 5 wherein said light emitting diodes are
arranged in a dot matrix.
7. A combination pager and message encoder comprising:
means for decoding a .Iadd.first .Iaddend.message transmitted to
said pager;
means for displaying said decoded .Iadd.first .Iaddend.message in a
precessing display in which characters in the .Iadd.decoded first
.Iaddend.message are laterally displaced a number of times to next
adjacent character locations so that the characters move across the
display from one side to the other side;
means including a keyboard for .Iadd.composing and
.Iaddend.encoding a .Iadd.second .Iaddend.message; and
means for coupling said .[.encoded.]. .Iadd.second .Iaddend.message
to said precessing display, whereby a single precessing display is
used for both message reception and message .[.encoding.].
.Iadd.composition. .Iaddend.
8. The combination pager and message encoder of claim 7 wherein
said encoding means further includes means for forming a serially
encoded message stream corresponding to said encoded message.
9. The combination pager and message encoder of claim 8 and further
including means adapted to couple said message stream to a
telephone line via an acoustic coupler.
10. The combination of claim 8 and further including means at said
pager and encoder for directly transmitting said message stream to
other pagers in the vicinity of said pager-encoder combination.
11. In a pager adapted to receive .Iadd.encoded .Iaddend.messages
transmitted from a remote location,
means for decoding the transmitted message .Iadd.into a form
suitable for display; .Iaddend.and
means for displaying said decoded message in a precessing display
in which characters in said decoded message are laterally displaced
a number of times to next adjacent character locations so that the
characters move across the display from one side to the other.
12. For use in combination with common carrier paging transmission
apparatus having .[.a voice.]. .Iadd.an audio
.Iaddend.channel.Iadd.,
a device including .Iaddend.an encoder remote from said apparatus
having a keyboard for entering a message and means for transmitting
to said paging transmission apparatus a series of coded audio tones
indicative .[.to.]. .Iadd.of .Iaddend.the message entered at said
keyboard.Iadd., said device including a precessing display for
displaying portions of the message entered at said keyboard in
which characters are laterally displaced a number of times to next
adjacent character locations so that the characters move from one
side of the display to the other; .Iaddend.and
means for coupling said encoder to the audio channel of said
transmitting apparatus, whereby the encoded message may be
transmitted to a predetermined recipient via said audio channel
after said apparatus has transmitted a predetermined address.
.[.13. The encoder of claim 12 and further including a precessing
display at said encoder for displaying portions of the message
entered at said keyboard in which characters are laterally
displaced a number of times to next adjacent character locations so
that the characters move from one side of the display to the
other..].
4. The encoder of claim .[.13.]. .Iadd.12 .Iaddend.wherein said
precessing display includes a recirculating memory for storing the
message entered at said keyboard, and means for driving said
display in accordance with the output of said recirculating memory,
said recirculating memory being coupled to said precessing display
through said drive means for driving it in a precessing manner with
the recirculation of said memory.
. A method for transmitting an alpha/numeric message to a
predetermined pager adapted to receive and display the message
.Iadd.and having an address.Iaddend., comprising the steps of:
.Iadd.encoding said message and, simultaneously in a precessing
alpha/numeric display, precessing said message across said display
such that characters in the message are laterally displaced a
number of times to next adjacent character locations so that the
characters move from one side of the display to the other;
.Iaddend.
dialing a telephone number corresponding to said
.[.predetermined.]. address,
transmitting signals on an RF carrier.Iadd., .Iaddend.indicative of
said .[.predetermined.]. address to activate said predetermined
pager from a central transmitter .Iadd.remote from said encoding
and from said display.Iaddend.; .[.and.].
.Iadd.wherein said encoding step, said dialing step and said first
transmitting step being performed in any relative order, provided
that said dialing step precedes said first transmitting step and
said second transmitting step;
converting the encoded message produced by said encoding step into
a series of audio tones indicative of said message; .Iaddend.
.[.generating a series of audio tones indicative of.].
.Iadd.coupling said audio tones to said transmitter; and
transmitting .Iaddend.said message on the carrier from said central
transmitter after transmitting said address signals.[., said
generating step including the steps of encoding said message at a
location remote from said transmitter, converting said encoded
message into audio tones, and coupling said audio tones to said
transmitter.].. 16. A message encoding unit comprising:
means including a keyboard for encoding a message;
a memory for storing the encoded message;
a display including an arrangement of display elements, selected
elements being .[.actuateable.]. .Iadd.actuatable .Iaddend.to
present an alpha/numeric character;
means for driving said display in accordance with selected
characters in said memory such that a portion of an alpha/numeric
message is presented by said display at any given time, said drive
means including means for precessing said message across said
display such that characters in the message are laterally displaced
a number of times to next adjacent character locations so that the
characters move from one side of said display to the other; and
means for decoding the message in said memory and for making said
decoded
message available at an output thereof. 17. The message encoding
unit of claim 16 wherein said memory includes a recirculating shift
register memory and wherein said drive means includes means for
incrementing said
shift register memory. 18. The message encoding unit of claim 17
wherein said means for making said decoded message available
includes means coupled to said memory for converting the message
therein into a serial bit stream and means for coupling said serial
bit stream to said output.
. The message encoding unit of claim 16 wherein said drive
means
includes means for inhibiting said precession. 20. The message
encoding unit of claim 19 wherein said memory includes a
recirculating shift register memory, wherein said drive means
includes means for incrementing said shift register memory and
wherein said precession inhibiting means
includes means for inhibiting said incrementing means. 21. The
encoding unit of claim 16 wherein said display includes a dot
matrix arrangement of
display elements. 22. The encoding unit of claim 16 wherein said
display
includes light emitting diode elements. .Iadd.23. A combination
pager and message encoder comprising:
means for decoding a first message transmitted to said pager;
means for displaying said decoded first message in a precessing
display in which characters in the decoded first message are
laterally displaced a number of times to next adjacent character
locations so that the characters move across the display from one
side to the other;
means including a keyboard for composing and encoding a second
message; and
means for coupling said second message to said displaying
means,
whereby a single precessing display is used for both message
reception and
message composition. .Iaddend. .Iadd.24. The encoder of claim 14
wherein said recirculating memory comprises a memory of capacity
greater than that necessary to contain as many characters as can be
displayed in said display at any one time. .Iaddend. .Iadd.25. A
method as recited in claim 15, wherein said encoding step comprises
encoding said message in a memory remote from said central
transmitter. .Iaddend. .Iadd.26. A method for transmitting an
alpha/numeric message to a predetermined pager adapted to receive
and display the message, comprising the steps of:
dialing a telephone number corresponding to a predetermined
address;
transmitting signals on an RF carrier indicative of said
predetermined address to activate said predetermined pager from a
central transmitter; and
generating a series of audio tones indicative of said message on
the carrier from said central transmitter after transmitting said
address signals, said generating step including the steps of
encoding said message while simultaneously displaying said message
in a precessing alpha/numeric display which precesses said message
across said display such that characters in the message are
laterally displaced a number of times to next adajcent character
locations so that the characters move from one side of the display
to the other at a location remote from said transmitter, converting
said encoded message into audio tones, an coupling said audio tones
to said transmitter. .Iaddend. .Iadd.27. A method as recited in
claim 26, wherein said encoding step comprises encoding said
message in a memory at a location remote from said central
transmitter. .Iaddend.
Description
FIELD OF THE INVENTION
This invention relates to paging systems and.Iadd., .Iaddend.more
particularly.Iadd., .Iaddend.to a hand held pager which silently
stores the message transmitted to the recipient in such a manner
that the message can be read out at the convenience of the
recipient by a precessing display.
BACKGROUND OF THE INVENTION
It is common practice to provide pagers which emit an audible tone
indicating that a particular recipient is to receive a message.
Thereafter, the message is transmitted via voice communication to
the recipient whether or not this recipient is ready to receive the
message. As a result, the content of the message is sometimes lost
when the recipient either cannot remember the content of the
message or a pencil and paper is not immediately available to
transcribe the message. This is particularly severe when telephone
numbers or addresses are transmitted. The result is frustration of
the recipient and the necessity of communicating with the
originator of the message to obtain its content. In one broad
aspect.Iadd., .Iaddend.this invention alleviates the inconvenience
of the prior art paging systems by providing storage and recall of
the transmitted message through the use of a precessing display of
a stored message (soft copy unit) in an unattended unit.
In another broad aspect of this invention.Iadd., .Iaddend.a
portable encoder unit is coupled via a telephone link to a common
carrier paging transmitter. The system is compatible with existing
transmitters and permits the encoding of messages anywhere that
telephone service is available. It is a feature of the subject
invention that the encoded message may be transmitted through the
common carrier transmitter audio channel as a substrate for voice
communication without alteration of existing unattended
transmitting equipment. In this regard, in one embodiment.Iadd.,
.Iaddend.the encoder includes a message entry keyboard and means
for converting the entered message into a series of audio tones for
transmission on the audio channel after the transmitter has
automatically sent a predetermined address code.[.,.]. responsive
to the dialed telephone number. Thus.Iadd., .Iaddend.no additional
message encoding apparatus or tone generating equipment is
necessary at the common carrier transmitter. In one
embodiment.Iadd., .Iaddend.the encoding unit may include a
precessing display for message editing and review prior to
transmission.[.,.]. or.Iadd., .Iaddend.alternatively, other types
of editing displays may be used.
As illustrated in U.S. Pat. No. 3,846,783 issued to Aspell et al.
on Nov. 5, 1974, it is known to provide a pager with a hard copy
printout. While the Aspell patent describes generally the use of
light emitting diodes or liquid crystals for displaying a message,
the subject invention provides, in one embodiment, for a precessing
display which rolls by characters across a limited field. This type
display permits the display of messages which have a greater length
than the display by precessing the message across the display.
In one embodiment.Iadd., .Iaddend.the pager utilizes a ROM-driven
LED dot matrix display fed by a recirculating shift register memory
which generates the precession as it recirculates. In another
aspect of the subject invention.Iadd., .Iaddend.the LED display
enables the presentation of the message in the dark a portion at a
time. In the subject soft copy pager, the message is stored in the
pager's memory and may be recalled at the convenience of the
recipient by a precessing alpha/numeric display so that the
information contained in the message can be made available at the
convenience of the recipient. In a further embodiment.Iadd.,
.Iaddend.the soft copy pager is provided with encoding means so
that a message can be composed on the soft copy unit prior to its
transmittal to a high power transmitter for transmission to another
paging unit.
It is therefore an object of this invention to provide an improved
hand held paging system in which a message transmitted to a
recipient is stored at the pager for readout at the convenience of
the recipient.
It is another object of this invention to provide a pager which is
inexpensive, silent and displays a message in alpha/numeric form a
portion at a time.
It is a further object of this invention to provide a method of
transmitting a message in which the message is stored at a remote
location in a memory and in which the message is recalled by the
recipient at his convenience through the use of a precessing
display.
It is another object of this invention to provide a precessing
display pager in which the precession is generated by a
recirculating shift register.
It is .[.a.]. still .Iadd.a .Iaddend.further object of this
invention to provide a soft copy pager which may be utilized both
for the receipt of a transmitted message and for the encoding of a
message to be transmitted thereby combining in one unit the two
functions.
It is .[.a.]. yet still .Iadd.a .Iaddend.further object of this
invention to provide a paging system in which messages may be
locally encoded and transmitted on the audio channel of existing
unattended common carrier transmitting equipment.
These and other objects of this invention will be better understood
in connection with the following .[.desription.]. .Iadd.description
.Iaddend.in view of the appended drawings in which:
FIG. 1 is a diagrammatic representation of a soft copy
pager/message encoder combination which utilizes a precessing
display;
FIG. 2 is a block diagram of one embodiment of the pager/encoder of
FIG. 1; and
FIG. 3 is a more detailed block diagram of a portion of the
pager/encoder of FIG. 2.
DETAILED DESCRIPTION
Referring to FIG. 1.Iadd., .Iaddend.a pager 700 is illustrated in
which a received message is reproduced in alpha/numeric form by a
precessing display 702. This pager also can be used for message
encoding and has a keyboard 704 for this purpose. The pager has an
internal memory into which a message may be written, either by
receipt of a transmitted signal or by local keyboard message entry.
In the encoding mode.Iadd., .Iaddend.the message is .[.enetered.].
.Iadd.entered .Iaddend.into the internal memory and then
transmitted by an acoustic link 706 to a transmitting station. In
one embodiment, the encoded message is displayed on a .[.12.].
.Iadd.twelve .Iaddend.character precessing LED display which is
utilized for message composition and for editing prior to message
transmission. A sufficient number of keys are provided on the face
of the message encoder/soft copy pager to permit correction and to
initiate readout of the encoded message from the internal memory of
the pager. The encoded message is made available at link 706 which
is acoustically coupled through telephone lines to a remote high
power transmitting station. Alternatively, the message encoder/soft
copy pager may be provided .Iadd.with .Iaddend.a transmitter such
that the address and message may be transmitted from this unit for
a short distance to other pagers within the area. For this purpose,
a collapsible antenna 712 is provided.Iadd., .Iaddend.as
illustrated.
In either the receiver or encode mode.Iadd., .Iaddend.the message
in the memory is precessed across the display. By precessing is
meant that the message is made to travel across the display such
that the portion of the message that has already been viewed
disappears, while at the other end of the display new portions of
the message are generated. As will be appreciated, receipt of a
message may be indicated by any convenient message indicator.
Various indicator lights, generally indicated by reference
characters 708, are available on the face of the unit to indicate
the various modes of operation of the device such as an indication
of Power-On and receipt of a message, that a compose cycle is
selected, that a message is being transmitted.Iadd., .Iaddend.or
that a message is being held. The recipient displays the message by
pressing an appropriate key on the keyboard. Should the recipient
wish to stop the message from precessing.Iadd., .Iaddend.a "freeze"
switch 710 is provided. In this embodiment.Iadd., .Iaddend.the
receipt of a new message automatically clears the old message from
the memory included in the soft copy pager unit. In .[.anaother.].
.Iadd.another .Iaddend.embodiment.Iadd., .Iaddend.the messages can
be made to "stack" into memory in the order in which they
arrive.
In operation, a message for the soft copy pager is transmitted
with, for instance, a predetermined digital address. After decoding
of the address, the FSK message code is decoded within the pager
and stored in an internal memory. This memory is read out in a
precessing fashion to a character decoding read only memory (ROM)
which is .[.utilied.]. .Iadd.utilized .Iaddend.in driving an
electronic alpha/numeric display.
It will be appreciated that this pager serves the function of
preserving the message for recall at the convenience of the
recipient while.Iadd., .Iaddend.at the same time.Iadd.,
.Iaddend.providing that the message may be stored silently and
recalled silently thereby not disturbing individuals in the
vicinity of the pager.
Thus, in one unit.Iadd., .Iaddend.a message encoder and message
receiving apparatus is combined. The significance of the
combination is that the same precessing internal memory and the
same read only memory may be utilized for message encoding and
message decoding. Thus, in one embodiment.Iadd., .Iaddend.pager 700
functions as a soft copy pager, a message encoder, and a message
transmitter. A block diagram of one embodiment of the soft copy
pager of FIG. 1 having these three capabilities is illustrated in
connection with FIG. 2 and is now described.
Referring to FIG. 2, a block diagram of one embodiment of the soft
copy digital message communicator is illustrated as including a
receiver 720 connected to an antenna 722. The output of the
receiver is connected to an FSK demodulator 724. The output of the
FSK demodulator includes serial data which is coupled both to a
clock extractor 726 and to a serial-to-parallel register 728. The
output of the serial-to-parallel register is the ASCII code of the
incoming data. This is applied to a six pole, two-position switch
730 which.Iadd., .Iaddend.in the receiver mode.Iadd.,
.Iaddend.couples the data to the recirculating shift register
memory. In the second position.Iadd., .Iaddend.switch 730 couples
keyboard generated ASCII characters into the memory. In this
figure.Iadd., .Iaddend.the recirculating shift register memory is
indicated by reference character 732 and the keyboard by reference
character 734.
The output of the FSK demodulator 724 is also coupled to an address
or I.D. code recognition circuit 736 which, upon decoding of the
proper ASCII character sequence, couples a signal to a mode control
circuit 738 which forces the system into the receive mode by
control of switch 730 and control of a clock extractor 726 which
inter alia provides timing for the data transmission in the
transmit mode. A signal is also transmitted over line 739 from the
ID code recognition circuit to clear memory 732 in response to a
signal indicating a mode change from mode control circuit 738. The
status of the system is indicated by status indicators 741 which
are driven by the mode control circuit.
In the receive mode, data from the serial-to-parallel register 728
is transmitted to recirculating shift register memory 732 which is
under control of memory control shift register 740. The purpose of
the memory control register is to ascertain the length of the
message stored in memory 732 and the beginning thereof. This
permits the readout of the message from memory 732 to the dot
matrix character ROM 742 following the complete reception of the
message. The dot matrix character ROM is read out to a row driver
and multiplexer 744 and to a data refresh and keyboard decoder
timing circuit 746. The display refresh and keyboard decoder timing
unit 746 provides the appropriate timing signals for the column
driver herein indicated by the reference character 748 such that
the columns are actuated in the proper sequence to display memory
contents. The display in one embodiment is a .[.12.]. .Iadd.twelve
.Iaddend.character LED dot matrix display 750 such as MONSANTO
MKA3. The line between ROM 742 and display refresh and keyboard
encoder 746 illustrated by line 752 is a two-way line which
controls the timing of the character readout from the dot matrix in
terms of the row driver and synchronizes this with the column
driver activation and the multiplexing thereof.
It is an important feature of this portion of the soft copy unit
that the message be stored in the memory for readout at the
convenience of the recipient and also that the message be formed in
such a way that it can be precessed across the dot matrix display.
Readout of the message is accomplished by actuation of switch 754
which activates mode control 738 to establish a signal on line 756
thereby to control shift register timing and control unit 758 to
activate the memory control register 740 which.Iadd., .Iaddend.in
turn.Iadd., .Iaddend.activates memory 732 to serially dump its
contents through to the dot matrix character ROM 742 in a
recirculating manner thereby to cause the displayed characters to
precess. Auxiliary switch 760 is provided to freeze the precession
by controlling the memory control register.
It will be appreciated that memory 732.Iadd., .Iaddend.in
essence.Iadd., .Iaddend.acts as a refresh buffer to restore the
readout characters so that they can be read out again during
recirculation. Thus, memory 732 in one sense is not a destructive
memory and will destruct the data therein only upon command
stimulated by the receipt of a new message, or by clearing due to
keyboard encoding.
What has been described so far is the decoding of a received
message by the subject soft copy unit. As mentioned
hereinbefore.[.,.]. in connection with FIG. 1.Iadd., .Iaddend.it is
possible to use this same unit for encoding the message and
displaying the encoded message prior to transmission. In this
sense.Iadd., .Iaddend.the display is utilized in the formulation of
the message and can be utilized in a manner so that errors in the
message may be corrected prior to transmission. To accomplish
this.Iadd., .Iaddend.the message is encoded by actuation of
keyboard 734 which.Iadd., .Iaddend.in turn.Iadd., .Iaddend.actuates
display refresh and keyboard encoder timing 746 to generate a
.[.6.]. .Iadd.six .Iaddend.bit character code over line 762 which
is coupled to switch 730 to enter the characters into the
recirculating memory. This line also initially carries a signal
which activates the mode control 738 to generate a signal coupled
to switch 730 to switch from its receive mode to a message
composition mode. Thereafter, the message is entered into the
recirculating register from the keyboard and is simultaneously read
out via the dot matrix character ROM to the display as described
hereinbefore.
It will be appreciated that the output of the memory 732 is coupled
to a parallel-to-serial converter 770 which converts the ASC II
coded characters into a serial transmission for actuating FSK
modulator 772 to modulate transmitter 774 to transmit the data. In
the receive or encode mode, although data is continuously coupled
from memory 732 to parallel-to-serial conversion unit 770.Iadd.,
.Iaddend.there are no clock pulses delivered to this unit so that
no data is transmitted. When, however, the message to be
transmitted has been successfully encoded, a character of a special
type is transmitted on line 762 to the mode control unit 738, which
forces the mode to the transmit mode. This develops a signal on
lines 775 and 776 to actuate the transmitter and to actuate clock
extractor 726 to produce clocking pulses on line 778 thereby to
clock the parallel data into the parallel conversion unit 770 from
whence it is coupled to the FSK modulator. It will be appreciated
that the transmitter utilized may be internal to the soft copy unit
or may be remote therefrom for the transmission of both the address
and the message to another remote paging unit which may be either
an identical soft copy unit such as described, or a hard copy unit
in which digital addressing is utilized. The FSK output as
illustrated by line 780 may be coupled to a suitable modem which
transmits the address and message over standard telephone circuits
to a remote transmitter such that the subject soft copy message
communicator may be utilized solely as the encoder. Thus.Iadd.,
.Iaddend.encoders at different locations may be connected via a
telephone link to the same transmitter with appropriate circuitry
at the transmitting station to prevent overlap or to allow
sequential access.
The precession of the display is accomplished, in one embodiment,
as follows. The first character which is entered into the
recirculating shift register memory from switch 730 causes a single
one bit wide pulse to be clocked into the memory control register
740. This bit will subsequently be referred to as the
.Iadd.".Iaddend.pointer.Iadd." .Iaddend.bit. The purpose of the
pointer bit is to indicate the beginning of the message within the
total length of the shift register memory. Its secondary function
is to indicate the beginning of the display refresh cycle within
the shift register memory when it is used for that purpose.
A second function of memory control register 740 is to provide a
timing pulse to indicate the duration of the message stored in the
memory. This is accomplished by clocking into memory control
register 740 a logic level "1" bit each time a new character is
clocked into the recirculating shift register memory 732. In this
way.Iadd., .Iaddend.a logic level .Iadd.".Iaddend.1.Iadd."
.Iaddend.pulse is formed in the memory control register which is
coincident or synchronous with the message character contents of
the recirculating shift register memory.
It will be appreciated that a .[.6 .Iadd.six .Iaddend.bit ASCII
coded message is serially clocked into the recirculating shift
register memory. The beginning of this message is indicated by the
aforementioned pointer bit and its duration .[.in.]. .Iadd.is
.Iaddend.indicated by the number of logic level
.Iadd.".Iaddend.1.Iadd." .Iaddend.bits entered into the memory
control register. This permits the recirculation of the message in
the shift register memory via a feedback circuit within the shift
registers. For this purpose.Iadd., .Iaddend.shift registers
.[.menufactured.]. .Iadd.manufactured .Iaddend.by National
Semiconductor Co., model MM5056 may be utilized.
The clocking of the message so as to permit recirculation is
accomplished via the output terminals of the shift registers within
the memory control register. Depending on which portion of the
cycle is then present, a certain number of clocking pulses are
provided to the recirculating shift memory to .[.accomplsih.].
.Iadd.accomplish .Iaddend.the recirculation. The clocking for
recirculation is many times that for readout so that reloading of
the memory during recirculation is done at a fast rate between two
readout clock pulses. The pointer pulse and the length of message
pulses are decoded such that fast timing pulses to the memory are
only delivered for a length of time sufficient to recirculate the
message. In order to stop the message at the appropriate point of
its beginning, the pointer bits are recognized and the quick
recirculation is terminated.
In the receive mode.Iadd., .Iaddend.the precession takes place
automatically because the pointer bit is automatically shifted via
the timing control circuit to the memory control register.
.[.this.]. .Iadd.This .Iaddend.is accomplished by a timer
comprising a monostable multivibrator within shift register and
timing control circuit 758 which, when it times out, produces a
clock pulse which shifts the pointer bit in the memory control
register by .[.1.]. .Iadd.one .Iaddend.bit. In so doing, one
character from the portion of the memory displayed is dropped and
one character from the portion of the memory not displayed is
added. The time constant of this monostable multivibrator is made
compatible with the precession rate desired. It will be appreciated
.Iadd.that .Iaddend.by altering the timing components of the
multivibrator.Iadd., .Iaddend..[.that.]. the procession rate can be
easily varied. Moreover, the precession rate is not controlled by
any fixed counter or counting-type logic but rather is simply
dependent upon the time out period of the multivibrator. The
automatic time out feature is disabled during the encode mode by
the mode control circuit.
The output signals from the recirculating shift register memory are
applied as inputs to the dot matrix character ROM 742. The dot
matrix character ROM drives the row driver multiplexing circuit 744
and.Iadd., .Iaddend.via the display refresh and keyboard encoder
timing circuit 746.Iadd., .Iaddend.drives the column driver and
multiplex circuit 748 such that characters are read out of the dot
matrix ROM in five columns per character. Because of the
recirculation of the shift register memory, the dot matrix
character ROM is refreshed with the message such that, in one
embodiment, the .[.12.]. .Iadd.twelve .Iaddend.most recent
characters are decoded by the ROM and are displayed. A Fairchild
Memory Model No. 3257 is utilized as the dot matrix character ROM.
It will be appreciated that row driver 744 includes switchable
current sources for applying a voltage to the appropriate rows of
the LED dot matrix display 750. The columns of these displays are
actuated by the display refresh and keyboard encoder timing 746
which sequentially actuates the columns to produce the characters.
This completes the description of the generation of a precessing
display when the paging unit is in the receive mode.
In the encode mode, one of the functions of the pointer bit is to
blank the display so that as each character is entered via the
keyboard.Iadd., .Iaddend.it replaces a blank portion of the display
with the appropriate character. In normal operation, .[.te.].
.Iadd.the .Iaddend.recirculating shift register memory refreshes
continually. With the advent of the pointer bit.Iadd., .Iaddend.the
recirculating shift register cyclically reads out blank characters
or spaces. Upon the depression of a character key.Iadd.,
.Iaddend.this character is added after the pointer bit and the
blank characters are shifted one position to the right in the shift
register such that one of the blank characters is lost and one
character is added. This is reflected in the next character refresh
cycle and the key depressed is now present for visual verification.
The character refresh is going on all the time and at a very rapid
rate such that the columns of the matrix display are rapidly and
sequentially actuated via the clocking of the display.Iadd.,
.Iaddend.which also reads out the dot matrix character ROM. It will
be obvious that the refresh cycle must be sufficiently rapid to
avoid flickering of the display. It is therefore important when
entering a character into the recirculating shift register memory
that this be done at the appropriate time. In this case.Iadd.,
.Iaddend.the appropriate time means at the end of a refresh cycle.
It is therefore the function of the pointer bit to insure that the
character is entered into the recirculating shift register memory
at this particular point and time. When a character key is
depressed.Iadd., .Iaddend.the pointer bit is delayed by one bit
position within the memory control register. This permits the next
character to be entered at the correct time in the refresh cycle.
When the display is full (.[.12.]. .Iadd.twelve .Iaddend.characters
displayed) the delay of the pointer bit by .[.1.]. .Iadd.one
.Iaddend.bit results in the display now presenting the characters
following this pointer bit such that one character is deleted and
one character is added.
By the shifting of the pointer bit, what is displayed therefore are
.[.11.]. .Iadd.eleven .Iaddend.old characters and one new character
with the new character being the last one entered. This corresponds
to a manual precession of the display such that the precession is
controlled by the position of the pointer bit within the memory
control register. What has been accomplished.Iadd.,
.Iaddend.therefore.Iadd., .Iaddend.is that by the depression of
keys in the keyboard.Iadd., .Iaddend.a message is loaded into the
recirculating shift register memory in timed relationship to the
refresh cycle which is established by a pointer bit originated by
depression of a control key and the appropriate character key in
the keyboard. Since the recirculating shift register memory is
continually read out to the dot matrix character ROM, what is read
out of the shift register memory is displayed. Thus.Iadd.,
.Iaddend.changes in data held by the memory are immediately
displayed.
Editing of the encoded message is accomplished very simply by
precessing the display to the point where the inaccurate or error
character is at the right hand most portion of the display. This
corresponds to the pointer bit location and merely entering the
appropriate correction at that time replaces the character in error
with the corrected character. .[.the.]. .Iadd.The
.Iaddend.corrected character then appears at that display position
corresponding to the key depressed.
Thus.Iadd., .Iaddend.a convenience feature of this particular pager
is that there is provided on the keyboard a key which, when
activated simultaneously with the control key, causes the
precessing circuit to time out such that the display
.[.precessed.]. .Iadd.precesses .Iaddend.by one character at a time
in a forward direction, corresponding to one depression of the key.
This enables editing of the message by .[.exactly.]. .Iadd.the
exact .Iaddend.positioning of the message within the display such
that locating .[.of.]. the error character at the right most
display .[.positon.]. .Iadd.position .Iaddend.is easily
accomplished.
Another attractive feature of the subject pager is that by
.Iadd.activating .Iaddend.a simple freeze switch .Iadd.to its ON
position, .Iaddend.the automatic precessing circuit is disabled
thereby freezing the message on the display in .[.the.]. .Iadd.its
.Iaddend.position at the moment that the freeze switch is actuated.
Precessing continues when the precessing circuit is again enabled
by .[.throwing.]. .Iadd.changing .Iaddend.the freeze switch to its
OFF position. It will be appreciated that the freeze switch is in
the freeze position during message composition.
It will also be .[.appreicated.]. .Iadd.appreciated .Iaddend.that
by tapping off .[.of.]. the lines between the recirculating shift
register memory and the dot matrix character ROM to
parallel-to-serial conversion shift register 770, the encoded
message may be made available at the output of this shift register
for transmission.
In order to transmit the encoded message.Iadd., .Iaddend.a control
key is depressed on the keyboard along with a preselected character
key such that the recirculating shift register memory is read out
in a timed sequence compatible with the transmission of FSK
modulation to a transmitter. It will be appreciated that
parallel-to-serial conversion register 770 is loaded in synchronism
with the clocking of the recirculating shift register memory during
the specially timed readout. By virtue of the specially generated
clocking signals.Iadd., .Iaddend.the recirculating shift register
is read out in parallel a word at a time to the parallel-to-serial
conversion register. Thereafter, the parallel-to-serial conversion
register is clocked serially to read out this word.
With the output of the parallel-to-serial conversion register 770
being applied to a conventional FSK modulator.Iadd., .Iaddend.it
will be appreciated in one embodiment that the signal from the FSK
modulator may contain an address code followed by a message. The
addresses will, of course, be entered from the keyboard as a prefix
to the message to be transmitted. The pager which receives this
message obviously does not display the address code.Iadd.;
.Iaddend.but.Iadd., .Iaddend..[.is.]. rather.Iadd., is
.Iaddend.actuated after receipt and decoding of its particular
address code. Thus, in the case of digital addresses.Iadd.,
.Iaddend.the keyboard of the subject pager may be utilized to
formulate these addresses.
In another aspect of the subject invention.Iadd., .Iaddend.it is a
feature that the same counter provides a timing sequence to refresh
the LED dot matrix display by reading out the memory cyclically and
provides for the encoding of signals .[.(i.e., character codes).].
to be read into the recirculating shift register memory. In one
configuration, illustrated in FIG. 3, an n-bit binary counter 800
in display refresh and encoder timing circuit 746 is utilized which
has a certain number of least significant bits, for purposes of
illustration in this case, .[.4.]. .Iadd.four.Iaddend.. These
.Iadd.four .Iaddend.least significant bits are utilized through a
.[.1-out of-16.]. .Iadd.one-out-of-sixteen .Iaddend.binary decoder
circuit 802 to drive the display made up of multiple 5.times.7 dot
matrices 803 via column drivers 804 and to drive encoder keyboard
734 such that the data is read out in three character blocks. The
rows of matrices 803 are driven by row driver 806 in accordance
with dot matrix character generator 742. After the .[.4.].
.Iadd.four .Iaddend.least significant bits, the next least
significant bits are then routed to a row driver group enable
decoder 807.Iadd., .Iaddend.also in circuit 746.Iadd.,
.Iaddend.which is utilized to drive the next group of characters to
be presented. In this manner.Iadd., .Iaddend.the message is grouped
via sets of three characters and.Iadd., .Iaddend.in this
sense.Iadd., .Iaddend.the character generation and display is
multiplexed. The use of the n-bit binary counter sets the
multiplexing for the display such that a minimum of row and column
drivers are required. This counter is used both in the encoding of
a message when the message is to be encoded as well as in the
driving of the display. What will now be described is the
interaction of the keyboard with the n-bit binary counter to
provide the .[.6.]. .Iadd.six .Iaddend.bit ASCII character codes
during the encoding operation.
As mentioned before, a .[.one-out-of 1.]. .Iadd.one-out-of-sixteen
.Iaddend.binary decoder 802 is provided along with .[.15.].
.Iadd.fifteen .Iaddend.column drivers.[.,.]. and .[.16.].
.Iadd.sixteen .Iaddend.column keyboard matrix 734. The function of
this binary decoder is to decode the .[.4.]. .Iadd.four
.Iaddend.least significant bits of the n-bit binary counter and to
simultaneously drive both the column drivers in sets of five and
the .[.16.]. .Iadd.sixteen .Iaddend.columns of the keyboard
matrix.
In the generation of the .[.6.]. .Iadd.six .Iaddend.bit ASCII code
characters, the n-bit counter is continuously cycled via timing
logic 816 to sequentially present by its states all ASCII character
codes to a data register 808. Binary decoder 802 is also cycled to
produce output pulses at its output terminals in a serial fashion
so that during a complete cycle all characters are available as a
combination of the signals from the n-bit counter. At the same
time, the cycling binary decoder outputs are used to drive the
columns to the display. This cycling occurs very rapidly to prevent
flicker of the display. Since the outputs from the binary decoder
are applied to different keys in a timed sequence, depending
.Iadd.on .Iaddend.the key switch closed at a given time in the read
out cycle, an enable pulse correlated with the character to be
encoded is gated over line 809 to data register 808 which is fed in
parallel with the output of the n-bit binary counter. At any given
time.Iadd., .Iaddend.the n-bit binary counter has an output which
corresponds to a given character. Thus, at a given instant of time,
the state of the n-bit counter corresponds to a character, for
instance.Iadd., .Iaddend.the letter "M.[...].".Iadd.. .Iaddend.If
the M key is depressed at this time, then the data register is
loaded to encode M and this character is entered into the
recirculating shift register memory.
The gating logic for gating the enable pulse to the data register
is illustrated in dotted box 810 and operates in combination with
the fifth bit of the n-bit shift register. The fifth bit determines
whether it is the top or bottom row of the keyboard which is
actuated. In one embodiment, the keyboard has two rows and .[.16.].
.Iadd.sixteen .Iaddend.columns. An electronic (digital) switch is
provided to enable the choosing of which row of the keyboard is
actuated by controlling the state of the fifth bit in the n-bit
shift register. This electronic switch includes a shift key
812.
In summary, it is the function of the binary decoder in the display
refresh and keyboard decoder timing circuit 746 to provide .[.16.].
.Iadd.sixteen .Iaddend.output terminals and to produce sequentially
a series of pulses, each at a different output terminal
.Iadd.wherein .Iaddend.the time that each pulse is generated
.[.corresponding.]. .Iadd.corresponds .Iaddend.to a state of the
counter as it cycles through its .[.16.]. .Iadd.sixteen
.Iaddend.states and.Iadd., .Iaddend.therefore.Iadd., .Iaddend.a
character. This relates the output terminals to the character
represented by the state of the n-bit binary counter. Thus, if a
pulse appears at the .Iadd.".Iaddend.0.Iadd.".Iaddend.output of the
binary decoder.Iadd., .Iaddend.this corresponds to a state of the
n-bit binary counter and some predetermined ASCII character. If a
pulse appears on the .Iadd.".Iaddend.1.Iadd." .Iaddend.output of
the binary counter.Iadd., .Iaddend.this will occur at a subsequent
period of time and indicates that the n-bit binary counter has
changed thereby to recognize a different ASCII character. The
closing of a keyboard switch connects the pulse from an associated
output of the binary pointer to a gating system to provide a dump
signal to the data register which changes its ASCII output with
each change of the n-bit register. The binary decoder cycles
through its .[.16.]. .Iadd.sixteen .Iaddend.states sequentially
such that the depression of a key will produce a clock pulse to the
data register which clock pulse arrives at a time corresponding to
the given character. Thus, in a given sequence.Iadd., .Iaddend.the
delivery of a dump pulse to the data register results in the
dumping of the particular ASCII code to the recirculating shift
register memory. What has therefore been accomplished is that by
delivering a dump pulse to the data register at a particular
predetermined time in the sequence, the n-bit counter state is read
out for that character through the data register and into the
recirculating shift register memory as the appropriate ASCII
code.
It will be appreciated, however, that if the key in the keyboard is
depressed for a long period of time, absent any additional
circuitry, the character will be repetitively read into the memory.
This is undesirable since the depression of a key once is supposed
to result in only one character being read into the memory. A
circuit is therefore utilized which provides that for a single
depression of a keyboard key, only one character is read into the
recirculating shift register memory. Basically.Iadd., .Iaddend.this
is accomplished by reading a clock 314 pulse only once for one key
depression no matter how long the key is depressed. If multiple
characters of the same type are to be read in, the key must be
depressed a number of times.
Thus, the n-bit binary counter and binary decoder act as a single
logic block or circuit to decode the characters entered at the
keyboard while.Iadd., .Iaddend.at the same time.Iadd.,
.Iaddend.supplying timing signals to the column drivers of the
display. In this connection, counter 800 is stepped through states
representing all of the alpha/numeric characters. The binary
decoder decodes these characters and produces.Iadd.,
.Iaddend.sequentially.Iadd., .Iaddend.a series of timing pulses at
its output terminals. These signals sequentially actuate the
columns of the matrices via drivers 804. Simultaneously, an output
from a particular output terminal of the decoder defines a
particular state of counter 800 and thus a character. It will be
appreciated that counter 800 and decoder 802 are clocked quite
rapidly such that the columns are actuated in quick succession.
When a message is to be displayed, dot matrix character generator
742 is clocked and the first group row driver is enabled. Generator
742 produces the appropriate signals for energizing the appropriate
dots for the first column of the character to be displayed. On the
next clock pulse, generator 742 produces signals for energizing the
appropriate dots for the next column of this same character, etc.
Thus.Iadd., .Iaddend.the columns are always being quickly strobed
while the rows are actuated in synchronism.
For keyboard encoding purposes.Iadd., .Iaddend.the outputs of
decoder 802 function not as timing signals, but rather as signals
indicative of the state of the binary counter. For instance,
outputs 0-4 can correspond to characters A, B, C, and D. As
mentioned before, the fifth n-bit binary counter output can be used
to designate whether switches 1-16 are activated or switches 17-32.
Thus.Iadd., .Iaddend.the .[.16.]. .Iadd.sixteen .Iaddend.outputs of
the decoder can determine .[.32.]. .Iadd.thirty-two
.Iaddend.characters. If during the strobing a particular key is
depressed, sometime during the strobing cycle a pulse will be
delivered to logic 810 to cause data shift register 808 to transmit
a binary code to the recirculating shift register memory. Because
the pulse transmitted corresponds in time to a particular state of
the n-bit counter, the character read out of the n-bit counter at
this time is the one corresponding to the key depressed.
In this way.Iadd., .Iaddend.the same logic circuit serves to
generate one set of signals for both display timing and character
designation.
It will be noted that both the row drivers and the column drivers
are multiplexed. First.Iadd., .Iaddend.the leftmost group row
driver is activated simultaneously with the sequential activation
of the columns associated with the three leftmost column drivers.
After the first three matrices are activated, the next group row
driver is activated and the next set of three matrices is enabled.
Thus.Iadd., .Iaddend.the matrices are enabled in sets of three. In
this embodiment.Iadd., .Iaddend.row driver selection is
accomplished by circuitry within row enable decoder 807. It will be
appreciated that the column drivers are sequenced by the
connections of the column drivers to successive output terminals of
decoder 802.
Although a specific .[.emobdiment.]. .Iadd.embodiment .Iaddend.to
the invention has been described in considerable detail for
illustrative purposes, many modifications will occur to those
skilled in the art. It is therefore desired that the protection
afforded by Letters Patent be limited only by the true scope of the
appended claims.
* * * * *