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BACKGROUND OF THE INVENTION
1. Field of the Invention
Field is that of electronics and computers. Microprocessors, radio signals,
and CRT displays are involved.
2. Description of the Prior Art
Poignet et al, U.S. Pat. No. 4,361,848 discusses a teletext system in which
the news is formed into pages and transmitted on the vertical retrace of a
TV signal. The entire text of the news is transmitted repetitively. The
user pulls selected pages for viewing as they fly by. A first objection to
the system is that there is a delay between the time the user specifies
which page he desires to read and the time the specified page is delivered
to his display. A mean time of 15 seconds is indicated. For the Quinews
the desired page appears instantly. A second objection is that the piece
of information is transmitted a thousand times (approximately), which
means that another system (such as the Quinews) which transmits the text
only once, can transmit a thousand times as much code. Expressed another
way, a system such as the Quinews requires only one thousandth the
bandwidth as does a Poignet system. These advantages of the Quinews over
the Poignet system result from the fact that the Quinews provides mass
storage at the user site while Poignet does not.
Cox U.S. Pat. No. 4,388,645 discusses a teletext system in which satelite
transmission of coded pages to a cable head-end station is provided. The
station stores the coded pages and then converts and retransmits the news
content thereof as ordinary TV pictures. Retransmission is to end users of
the news. No code is transmitted to the user site. Operationally the
system is identical to the TV newscast. The only difference is that pages
of print are transmitted instead of pictures. The user must watch whatever
is transmitted from the head-end station. He may not select those stories
in which he is interested and pass the others by. He may not read any
story in depth. Whereas, with the Quinews he reads only those articles in
which he is interested--and he can read them in much greater depth. Mass
storage for the Cox system is at the head-end station. No storage
whatsoever is at the user site. The bandwidth required for the
transmission is 4.5 MHz, about 4,000 times that required by the Quinews.
Marti U.S. Pat. No. 4,303,941 describes a system similar to that of
Poignet. Only a single page of display storage is at the receiver--no mass
storage. Mass storage is at the transmitter. Consequently the Marti system
suffers the same shortcomings as does the system of Poignet.
The following U.S. patents are cited as being of interest.
Ciciera, U.S. Pat. No. 4,233,628
Guillou U.S. Pat. Nos. 4,323,921 and 4,337,483
Hernandez et al U.S. Pat. No. 4,308,558
Marti et al U.S. Pat. No. 4,290,062
Parsons U.S. Pat. No. 4,099,258
Sechet et al U.S. Pat. No. 4,354,201
SUMMARY OF THE INVENTION
A radio transmitter transmits the news as encoded pages. At the user site a
receiver delivers these encoded pages to a processor which in turn stores
them in memory. A first set of pages are directory pages--listing
headlines of news stories. A second set of pages are text pages--giving
the text of the news stories. The user views a directory page on a CRT
display and selects from it an article he wishes to read. Via a keyboard
he commands the computer to deliver selected pages of that article to the
display.
Significant features are:
1. There is no delay between selection of a story to be read and its
delivery to the display. This feature renders the Quinews superior to the
Teletext system of Poignet for which the delay is approximately 15 sec.
2. The user can read in depth those articles in which he is interested. He
avoids waste of time while things in which he has no interest are being
shown.
For the above two reasons the Quinews is superior to the system of Cox, to
the TV newscast, and to the radio newscast.
3. The headline news for the Quinews is 6 minutes old. For the newspaper it
is between 6 and 53 hours old. This renders the Quinews vastly superior to
the newspaper.
4. Each page of news is transmitted only once. In the Cox, Poignet, and
Marti systems each page is transmitted perhaps a thousand times.
Consequently a thousand times as much news can be transmitted in the
Quinews system as can be transmitted in the system of Cox or the system of
Poignet. Expressed another way, the Quinews requires only 0.1% of the
spectrum space required by the previous systems.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sketch of a Quinews installation.
FIG. 2 is a block diagram of the Quinews system.
FIG. 3 shows the top 3 lines of an ordinary text page. The 4 characters at
upper left appear in the text but are ordinarily suppressed in the
display.
FIG. 4 shows the top 4 rows and the bottom 2 rows of a typical directory
page.
FIG. 5 is a sketch of a typical control box.
FIG. 6 is diagram showing the sequence in which characters are transmitted
at the end of one page and the start of a new page.
FIG. 7 is a flow diagram or the Control program of the receiver.
FIG. 8 is a flow diagram for the VidFil routine of the receiver.
FIG. 9 is a flow diagram of the Rcv routine of the receiver.
FIG. 10 is a block diagram for the transmitter.
FIG. 11 is a flow diagram for the transmitter Executive program.
FIG. 12 is a flow diagram for the Load Available Page List program: ldapl.
FIG. 13 is a flow diagram for the Clear-page: clpg.
FIG. 14 is a flow diagram for the Page-Addresss: pads.
FIG. 15 is a flow diagram for the Keyboard: kbd.
FIG. 16 is a flow diagram for the Back-by-Character: bc.
FIG. 17 is a flow diagram for the Forward-by-Character: fc.
FIG. 18 is a flow diagram for the Back-by-Row: br.
FIG. 19 is a flow diagram for the Forward-by-Row: fr.
FIG. 20 is a flow diagram for the Back-by-Page: bp.
FIG. 21 is a flow diagram for the Forward-by-Page: fp.
FIG. 22 is a flow diagram for the Parent Directory: pdir.
FIG. 23 is a flow diagram for the Prime Directory: pmdir.
FIG. 24 is a flow diagram for the New Article: nart.
FIG. 25 is a flow diagram for the Clear Row: clrow.
FIG. 26 is a flow diagram for the Transfer: tf.
FIG. 27 is a flow diagram for the Delay: dly.
FIG. 28 is a flow diagram for the New Page: npg.
FIG. 29 is a flow diagram for the Repeat: rpt.
FIG. 30 is a flow diagram for the Delete: dlt.
FIG. 31 is a flow diagram for the Transmit Article: tma.
FIG. 32 is a flow diagram for the Article Pad: apad.
FIG. 33 is a flow diagram for the Transmit Page: tmp.
DESCRIPTION OF PREFERRED EMBODIMENT
How it is Used
Any time of day or night that the user desires to bring himself up-to-date
on the news he sits down before his "Quinews" (See FIG. 1). He turns the
display on. Immediately a directory listing 15 headlines appears.
Headlines are numbered down the left side. If he desires to read article
No. 5 he pushes a combination of keys representing "5" on the control box.
Immediately the first page of Article No. 5 appears on the display. There
are 10H rows of 20H characters per row. He scans the first page. If he
desires to read more of this article, he pushes the "Next Page"
combination on the box and the next page appears on the display. If he
desires to go back to the Headlines and select another article, he pushes
"Parent Directory". He might select "Features" which would cause a
directory listing of 15 features to appear on the display, from which he
could select "Bridge Game", "Stock Market", or perhaps "Advertising". The
last would bring up another directory from which he might select
"Clothing", which would bring up another directory from which he might
select "Pants", which would bring up advertisements from several stores,
each touting trousers for sale.
How it Works
a. A radio transmitter transmits the news as encoded pages, continuously.
It updates the headlines as the stories come in. It updates the bridge
game once per day, the stock market twice, and advertisements at the beck
of the sponsor.
b. A radio receiver in the home feeds these encoded pages to a
microcomputer which stores them in memory.
c. The user with his control box (user-input-device) selects "pages" from
memory for viewing on his display.
Significant Features
a. Collection, editing, and broadcast of the news is paid for by
advertising.
b. The user can read in depth those articles in which he is interested and
pass over articles in which he is not interested. Just as he does with a
conventional newspaper. He can do this just as he cannot do with a TV or
radio newscast.
c. Top news on the Quinews is approximately 6 minutes old. Top news in the
newspaper is between 6 and 53 hours old. The Quinews in this regard is
vastly superior to the newspaper.
d. The Quinews has associated with it no "paper" to print, deliver, and
later recycle. It has associated with it no costly presses. It has no
union gentlemen to go on strike. e. Cost of the Quinews is $50.00 if the
user already has a microcomputer. Some $250.00 if he does not.
The Encoded Page
Consider Encoded Page 5 of FIG. 2. This is a set of 200H encoded characters
arriving in sequence from an editorial office. These characters are
arranged into 10H rows of 20H characters each. Each news article is
divided into a sequence of these encoded pages.
The first two rows of the first encoded page of a typical news artcle
appear in FIG. 3. A headline appears in the first row. Text begins in the
second. At the left of the first row appear the digits "1234". These are
housekeeping characters and are identified as follows:
1. pad--"Page Address". This character specifies where in Memory 13 of FIG.
2 this page is to be stored. The first encoded page is stored at location
0200H. The second at 0400H. Third at 0600H. The last at FE00H. This
page-address is actually the memory address of the first character of the
page. The following 1FF characters of the page occupy the following 1FF
memory locations. Since all page-addresses end in 00, the page address is
completely specified by the upper byte only. The encoded pages pass to
Transmitter 7, thence via radio waves to Signal Receptor 9, and thence to
Receiver Processor 15. Processor 15 obtains the pad from the encoded page
and stores the encoded page at that addrress in Receiver Memory 13. Memory
13 stores the encoded pages at locations specified at the transmitter. In
more sophisticated systems much more memory will be used. The pad will
consist of two or more bytes. It becomes a set of encoded characters. In
the prototype system page length and memory size were selected so that the
pad reduced to a single byte. The pad becomes a set of characters
consisting of one character only.
2. ppad--"Previous-Page-Address". The pad of this previous page appears in
this ppad position. The reader of the Quinews uses the ppad of a current
page to return to the previous page and place it in the display. He can
repeat this procedure to review all previous pages of the article. For the
first page of each article there is no previous page and ppad is made
equal to pad.
3. npad--"Next-Page-Address". Use of npad is similar to the above use of
ppad. It permits the reader to scan forward through an article. For the
last page of an article there is no npad. The pad of the current page is
inserted in the npad position.
4. pdir-"Parent Directory". This is the pad of the directory page from
which the Article containing the current page was taken. After the reader
has read as much of the current article as he desires, he uses pdir to
return to the parent directory. From it he may select a new story. Or he
may return to its parent directory. The operation may be repeated until he
reaches the "prime directory"--which is a directory containing top
headlines of the moment and from which operation of the Quinews receiver
begins.
The Two Types of Pages
1. A first set of encoded pages are called Directory Pages. They list the
articles from which the user may select those he wishes to read. The first
4 rows and the last 2 rows of a Directory page are shown in FIG. 4. The
following points are significant:
a. The usual housekeeping information is carried in the first 4 characters
indicated by the digits 1, 2, 3, and 4 at upper left. The title appears in
the first row.
b. There are 15 headlines, each is numbered as imdicated. The 14 and 15 are
represented by E and F respectively. It is not desirable to use letters to
represent numbers, but the practice is established in the technology.
c. A column of blanks follows the numerals. In the encoded-page, each of
these positions is filled with an "hpad" (headline pad), the pad for the
first page of the article corresponding to the headline. Processor 15 of
FIG. 2 blanks each hpad before feeding a directory page to the display.
d. From the display page the reader selects that headline whose article he
wishes to read. He pushes its sequence number on his control box.
Processor 15 goes to the corresponding row of the directory, extracts the
hpad, and forms the address for the respective page. It pulls that page
from memory, and sends it to the display.
e. Each Directory constitutes a subset of the directory pages.
2. The second set of pages are Text Pages. They present the text of the
articles.
The Control Box (User Input Device)
See FIG. 5. The buttons labelled 1, 2, 4, and 8 are used in selecting a
page to be displayed. Those keys are depressed the sum of whose labels
equals the sequence number of the headline selected. For instance,
headline No. 6 would be selected by depressing buttons 2 and 4 at the same
time. Headline No. 13 would be selected by depressing buttons 1, 4, and 8
simultaneously. The zero key is used in generating the "relative jump"
commands:
Z 1 Display the previous page
Z 2 Display the next page
Z 3 Display the parent directory
Z By itself, display the Prime Directory
A combinational keyboard is the preferred user input device. A QWERTY
keyboard could be used--that or one of the many special keyboards which
are presently available. A voice recognition device will no doubt become
useful in the future. Wireless units will probably be popular with large
displays.
The Prime Directory
When the Quinews (the combination of the signal-receptor,
receiver-processor, receiver-memory, receiver-display, and control box) is
first turned on, it puts the "Prime Directory" into the display. The Prime
Directory gives the top headlines of the moment and the titles of
subordinate directories. It is the one page which has a permanent
address--it is always at address 0200H. It can always be placed in the
display by striking the zero key by itself. It serves as a base page--a
"home" position.
Oftentimes the user will be interested in just monitoring the news to see
if something exciting is occurring, in which case he will leave the
Quinews running and displaying the prime directory. In this "Monitor"
mode, the Quinews updates the display ever 3 seconds by transferring the
0200 page from memory to the display. This insures that when a new prime
directory is received into memory, it will be transferred immediately to
the display.
Bulletin Mode
Should a tornado approach or a massive traffic snarl develop, the
transmitter may move to "Bulletin" mode. It then transmits a page of text
to the 0200H position. This causes the bulletin to be displayed as rapidly
as it is received. Signals could be incorporated which would cause the
display to be activated and an attention tone to sound.
Memory Control
Receiver Memory 13 will generally be 95% filled. The remaining pages are
available for entering new articles. As the number of available pages
drops below the 5% figure, editors at the transmitter select articles to
be deleted. Pages assigned to those articles then become available for new
articles. Human judgement is necessary for making the decision as to what
articles to delete, as well as what articles to add. The pads for the
deleted pages are then placed on the apl (available page list). Pads are
drawn from the apl as new articles are transmitted. A computer at the
transmitter is used to insert the proper pad, ppad, npad, and pdir into
every transmitted page. It also inserts the proper hpad into each row of
each directory page.
Startup
When the Quinews receiver is first turned on, the transmitter will most
likely be transmitting text. The receiver must wait until it receives the
pad for the next page before it starts storing in text memory. To enable
the Quinews to know when a pad is to be received, an AA (10101010) is
transmitted immediately before the pad of each page, as shown in FIG. 6.
An AA is not a character in Rowcode (the code used by the Quinews).
Consequently it ought never appear in straight text. As soon as the
Quinews sees an AA, it knows that the next character will be a pad. It
then uses this next character as a loading address for the incoming page.
Although the AA will not appear in alpha text, it can appear as a number,
or be noise-generated. The chance of either is rather remote. No such
trouble has been encountered thus far. If such trouble should develop,
then two cascaded characters could be used to reduce the chance of error
by another order of magnitude. The second character might well be F0.
Noise
Noise will generally cause an error in the bit structure of a character,
which in turn will cause a word in the display to be misspelled.
Redundancy of the English language causes such an error to do virtually no
harm. However, sometimes the noise will cause a character to be added or
deleted. An added character causes the remainder of the text for that page
to be displaced to the right. But the next page will be properly
synchronized and fed to memory in the proper manner. Consequently no harm
is done. The added character is a small nuisance only.
But if one or more characters are lost, the Quinews will not be looking for
the AA unti after it has been received. Consequently the next page will be
lost. To reduce the chance of such, the transmitter inserts 8 dummy
characters before an AA (see FIG. 6). Deleted characters then cause only
the loss of an equal number of these dummy characters.
Directory Page Transmission
In general, about 8 pages of text will be transmitted and then a directory
page or pages. Only after the text pages of an article have been
transmitted should a headline for the story be incorporated into a
directory.
Similarly, a directory should be transmitted from which the headline for a
story is deleted before the memory pages of that article can be used in a
new article. Otherwise the user might note a headline, call for the
respective article, and find the pages not present. Note that bit zero of
a pad is always zero. It carries no information. This results from the
fact that each page is 200H characters. Consequently bit zero is available
for other use. Note also that the Quinews must know when the current page
is a directory. To provide this information, the transmitter sets the zero
bit of the pad for a directory page and resets it for the text page. The
Quinews determines the type of page by examining this bit.
Rowcode
The two most common codes are ASCII and EBCDIC. The latter is used only by
IBM and those supplying IBM compatible equipment. Both codes are for use
with the decimal numbering system and do not well accommodate a
hexadecimal system such as used by computers: Increased use of computers
will bring with it a steady shift from the decimal system over to the
hexadecimal system. Consequently it was felt that it would be better to
drop the two older codes in favor of a computer compatible code such as
Rowcode. A conversion chart giving conventional characters, their Rowcode
equivalents, and their ASCII equivalents is given in Table I. Rowcode uses
an 8-bit code and is arranged to accommodate a combinational keyboard,
giving rise to several oddities in the code. A total of 100H characters
are available. Enough for the hexadecimal digits, upper and lower case
alphabets, the Greek alphabet, a host of punctuation and special
characters, and a host of phonemes. Table I assigns characters to less
than half the available codes.
Receiver Programmer 17 of FIG. 2
In the prototype this was an Eprom which had been internally modified
(programmed) so that it can cause the system to function as above
described. The Eprom is similar to the cam programmers which have been
used in industry for many years. But it is equivalent to a cam programmer
having several thousand cams and attendant switches. A high-powered
microscope is required to see the "cams and switches" of an Eprom. The
setting of the cams is electrical in nature and invisible.
This programmer is the brain of the Quinews. However, it is not customary
to discuss the physical modifications which have been made to the Eprom,
but rather to speak of the program in accordance with which these physical
modifications have been made. We shall conform to custom.
There are three routines of interest:
a. Control Program. This is a supervisory program which responds to user
commands and coordinates the operations of the system.
b. VidFil. This is a routine which, when given a pad, transfers the
respective page from memory to the display.
c. Receiver Program (Rcv). When a transmitted character is passed from
Signal Receptor 9 of FIG. 2 to Processor 15, an interrupt is generated.
Processor 15 then jumps to this Rvc routine. This routine causes received
characters to be loaded into their proper positions in memory.
The programs were written or a computer using an 8080 microprocessor and an
SSM video board. Maximum address of memory was FFFF. Which corresponds to
10 HK of memory or 64 DK of memory.
The Control Program
See FIG. 7 for the flow diagram. The following numbered comments pertain to
respectively numbered steps of the diagram.
1. Initialize. Disable Interrupts--to prevent the RCV program from trying
to operate before a stack pointer has been specified. Initialize the stack
pointer. Put a 00 into rsw (rsw to be discussed later). Lastly, enable
interrupts.
2. Display Prime Directory. It is located at 0200H.
3. Delay--3 sec. During this delay the Prime Directory remains on the
display. Then it is updated.
4. Any Command from Keyboard? If not, then the Prime Directory is moved
again to the display.
5. Any Command from Keyboard? This is a fast loop--no 3 second delay.
6. Bring in Command. Command comes from the keyboard.
7. Article Select Command? There are three possibilities. The command may
be an Article Select command, a Remote Jump command (ppad, npad, pdir, or
pmdir). Or, the command may be illegitimate. Step 7 checks to see if the
command is an Article Select command.
8. Remote jump? If the command was not an Article Select command, then was
it a Remote Jump command? If not, then the command is illegitimate and the
operation is aborted.
9. Prime Directory Command? If the command is a Prime Directory command
then a jump back to the Prime Directory loop is made.
10. Form Jump Address. The one remaining possibility is that the command
was a ppad, npad, or pdir command. In which case the appropriate pad is
drawn from the current page and placed in the upper byte of a jump
address. The lower byte is zeroed.
11. Call VidFil. This puts the new page into the Display. And returns the
system to looking for a new command from the keyboard.
12. Is Present Page a Directory? An Article Select command is legitimate
only if the current page (the page being shown on the Display) is a
directory. This step checks for this requirement. If the current page is
not a directory, the operation is aborted.
13. Form Article Address. If the current page is a directory, then the hpad
is drawn from the selected row and used as the upper byte of a jump
address. The lower byte is zeroed.
14. Call Vidfil. This puts the called-for page into the Display and returns
the system to looking for a keyboard command.
VidFil Routine
The pad of the page to be moved to video must be in HL. The flow diagram
appears in FIG. 8. The following numbered comments pertain to
correspondingly numbered steps of the flow diagram.
1. Initialize. Put the upper byte of the code converter address into
scratchpad register D. Put the pad of the video page into pointer BC. Save
the pad of the text page to be displayed.
2. Blank First Four Characters of Video. These are housekeeping characters.
They need not be displayed.
3. Is this a Directory? It will be a directory if the least significant bit
is set.
4. Yes. Second character of Row? This is the first step of a loop which
moves the characters from memory to video. Recall tat the second character
of each directory row is an hpad and that it is to be blanked in video.
Steps 4, 5, and 7 accomplish this.
6. Fetch character from Memory. Convert to ASCII. In case the page being
delivered to the display is not a directory--it must be a text page. In
which case the address in memory point HL is used to fetch a character
from memory. The character is converted to ASCII since the SSM video board
used in the prototype required an ASCII input.
8. First Character of Row? This checks to see if we have finished one row.
9. First Character of New Page? If it is the first character of a new page,
then we are finished.
10. Add 20H to Loading Address. In the SSM video board operating in the 20H
character-per-row mode, the second 20H characters of each set of 40H
characters are ignored. This step jumps over these ignored characters.
11 & 12. If the page is a directory, and the character is the second of a
row--then the character must be blanked. Steps 11, 12, 4, 5, and 7 put the
blank into the display. If the page is not a directory, the operation is
aborted.
Receive Routine (Rcv)
When the Receptor of FIG. 2 receives an incoming character, it raises a
flag. Upon seeing the flag, the Processor interrupts the program it is
running and processes the character. After it has properly loaded the
character into memory, it returns to the program it was running prior to
the interrupt.
The following numbered comments pertain to correspondingly numbered steps
of the flow diagram given in FIG. 9.
2. Fetch rsw--(Receive Status Word). This word is stored at a location in
memory called mrsw. Rsw tells the processor what portion of the
receiver-program the processor should use in processing the next incoming
character. Upon receipt of that incoming character, the processor consults
rsw and then uses the specified portion of the program in processing the
incoming character. If the incoming character is one of the eight dummy
characters--it is ignored. If it is an AA--the processor gets ready to
receive a pad. If it is a text character, the processor gets ready to
store it in memory.
3. Text? Incoming character is text if rsw is 02.
4. Page Address (pad)? Incoming character is a pad for the incoming page if
rsw is a 01.
5. Beginning of Transmission (BOT)? Look for a "Beginning of Transmission"
character (AA) if rsw is a 00.
6. Set rsw to 01. The BOT character (AA) has been received. Rsw is changed
to 01. This will cause the Processor to treat the next incoming character
as a pad for the incoming page.
7. Bring Incoming Character (pad) into A. The character brought in is that
held in the Receptor.
8. Use pad to form Memory Pointer in HL. This pointer will then be used to
load the incoming page into memory.
9. Move pad to memory. This causes pad to occupy that memory position for
which it has been used to form a pointer.
10. Set rsw to 02. This will cause the processor to treat the next
character as text.
11. Inx H, SHLD Lad (Loading Address). Since the first character of the
page has been loaded to memory, the pointer (HL) is incremented to point
to the next position. The pointer is then stored in memory. It will be
retrieved when the next character arrives.
12. Bring into A / Store in Memory. Character is stored in Memory at that
location specified by the pointer stored in Lad.
13. Inx H / SHLD Lad. This prepares the pointer for the next character.
14. Last Word of Page? If it is, then the job is done.
15. If it was, then rsw is set to 00. This will cause the system to look
for the BOT character for the next page.
Hardware of the Receiver
Transmitter 1 of FIG. 2 in the prototype consisted of a casette recorder
interface board built by MITS and a wireless intercom unit built by RCA.
The interface board produced an FSK signal in which a 2,025 HZ signal
represented logic 0 and a 2,225 HZ signal represented logic 1. The
wireless intercom accepted this signal and amplitude modulated it onto a
175 KHZ carrier. The resultant signal was coupled to the 60 HZ line. In a
more modern system a radio transmitter similar to that used by police
could be used.
Signal Receptor 9 of FIG. 2 in the prototype system was the receiver
section of an RCA wireless intercom. In a commercial system it would be a
radio receiver matching the selected transmitter.
Control Box 11 in the prototype was a combinational keyboard similar to
that discussed in U.S. Pat. Nos. 4,067,431 or 4,490,056. In a preferred
commercial system the control box would still be a combinational keyboard.
Briefly, the combo keyboard has one key for each finger. Keys are
depressed in combinations much as a piano is played. The combinations
generate computer words directly. However, most installations will
probably use a QWERTY keyboard--because of sales factors. A voice input
device, an infrared remote control system, and an ultrasonic beam unit are
examples of other devices which could be used. Probably most input will be
via modem and arriving at the transmitter via telephone lines from an
editing office remotely located. The generic term for the several units is
"Receiver-Input-Device".
Other receivers 24 of FIG. 2 are each identical to Receiver 21.
Details of Transmitter. See FIG. 10. Keyboard 101
(transmitter-input-device) of Transmitter 1 enables an operator to enter
successively the encoded characters of a page of news. Each page consists
of 10H rows of 20H characters per row--a total of 200H characters. A
portion of Memory 109 is referred to as Text Memory and is used for
storing these pages of news. Each page being 200H characters permits page
boundaries to be adjusted so that the first character of each page has an
address described by--
xxxx xxx0 0000 0000
--where each x means that the digit may be either 1 or 0. A more compact
notation is--
x(xxx0)00.
Processor 107 feeds each character to Display 113. There a Display Page of
10H rows of 20H characters per row is assembled--permitting the operator
to check his keying. Processor 107 carries out successive instructions of
Program 105 stored in Programmer 103. A news article will consist of
several such pages. After all pages of the article have been assembled in
memory 109 and verified by the operator, the operator commands the | | |
