we
`tereo coder
`
`aes
`ae
`
`ACeBeaEaOTEeVSESEee
`
`
`
`Australia $A1:20
`Pee
`Amazon Ex. 1028
`OraL1a4ed NOLO
`ty:
`IPR Petition - USP 5,887,243 [Rais
`eTLna eanBole
`LeY(TeeBee COROl9,
`aTirate Meds Bi eele)
`nahgs ence)
`c
`WIPE ReraRtoreed
`eve
`CNhes
`EASTNt4
`‘
`REV
`Sra
`
`PMC Exhibit 2068
`PMC Exhibit 2068
`Apple v. PMC
`Apple v. PMC
`IPR2016-00753
`IPR2016-00753
`Page 1
`Page 1
`
`

`

`Baer!
`
`
`
`
`wiireless-
`
`APRIL 1977
`
`
`world|
`Electronics, Television,Radio, Audio
`No 1496
`Vol 83
`
`Contents
`35
`
`Time, gentlemen, please
`NRDCsurround-sound system by M. A. Gerzon
`News
`
`36
`39
`40
`44
`
`45
`48
`53
`
`,
`
`57
`60
`61
`
`‘65
`70
`73
`76
`
`79
`83
`93
`96
`
`Characteristics and load lines — 5 by S. W. Amos
`Wireless World amateur radio station
`Sensitive metal detector by D.E. ON. Waddington
`HLF. predictions -
`New of the month
`Bullock’s boardroom and the engineer
`Britain pioneered the integrated circuit
`Vmosdevices “middle of this vear”
`Education by radio in Honduras by M.K. Bates
`Literature received, 100 years ago
`Circuit ideas
`Simple noise generator
`Variable band-passfilter
`Ripple eliminator
`Viewdata — 3 by S. Fedida
`.
`.
`World of amateur radio
`Electronic rhythm unit — 2 by A. Battaiotto and G. Ronzi
`Letters to the editor
`,
`The Warden Report
`Current dumping amplifier
`- Advanced pre-amplifier design
`Broadcast stereo coder by T. Brook
`Power semiconductors by M. R. Sagin
`New products
`Just for therecord by A. D. Foster
`APPOINTMENTS VACANT
`
`
`INDEX TO ADVERTISERS
`
`
`Subscriptions:
`
`at Retail and Trade Counter, Paris Garden,
`London SE1.
`Current issue price 35p, back issues (if available) 5Op,
`By post, current issue 55p, backissues(1 available) 50p, order and payment to Room 11,
`Dorset House, London SEi 9LU.
`‘Editorial & Advertising offices: Dorset House. Stamford Street, London SE] 9LU.
`‘Telephones: Editorial 01-261 8620: Advertising 01-261 8339.
`Telegrams/Telex, Wiworld Bisnespres 25137. London. Cables. “Ethaworld. London SE 1.
`Subscription rates: [ year: £7.00 UK ana overseas ($18.20 USA and Canada), Student rate: 1 year, £3.50
`UK and overseas ($9.10 USA and Canada).
`Distribution: 40 Bowling Green Lane. London ECIR ONE.Telepnone 01-837 3636.
`Qakfield House, Perrymount Rd, Haywards Heath. Sussex RH1I6 3DH. Telephone.
`_ 0444 59188. Subscribers are requested to notify a changeof address.” © LP.C, Business Press Ltd, 1977"
`
`Page 1
`
`
`
`meranionat Gusiness
`
`Dress Assneates
`
`
`
`
`
`
`PMC Exhibit 2068
`PMC Exhibit 2068
`Apple v. PMC
`Apple v. PMC
`IPR2016-00753
`IPR2016-00753
`Page 2
`Page 2
`
`
`
`fE
`
`
`
`
`
`
`
`
`
`
`
`
`Front cover,
`showing the
`medium wave aerial at Radio-
`landia, Comayagua, Honduras,
`introduces the article on edu-
`cation by radio in that country
`(page 57).
`Photographer Paul Brierley
`
`IN OUR NEXTISSUE
`Electrolytic capacitor
`tester.
`
`Enables ‘the. value of an electro-
`lytic capacitor to be measured
`automatically and the -result
`_displayed directly by meter.
`- Leakageis also indicated.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Two-stage linear amplifier. A
`discussion of
`the
`design”
`of
`solid-state
`5OW and 300W
`linear amplifiers for the h.f. band
`(1.6-30MHz).
`
`the ‘80s, a took
`Radio in
`forward to sound receiver design
`and the ideal set of the future by
`the BBC's chief cnginecrof radio
`- broadcasting.
`
`
`
`
`
`
`
` ISSN 0043 6062
`
`

`

`Wireless World, April 1977
`
`VIEWDATA
`
`
`
`65
`
`3 — Operation of the system: terminals and codes
`
`by S. Fedida, B.Sc. (Eng), M.Sc., F.1.E.E., A.C.G.i. Post Office Research Centre
`
`Wd
`
`Fharcorcisnad
`
`Bhool
`
`‘Part 1 of this series, in the February
`issue, gave an introduction to View-
`data, with mentions of earlier sys-
`tems. Part 2, in the March issue, dealt
`mainly with applications. This article
`inow describes the overall arrange-
`ment of the system, the codes used
`and the Viewdata terminal.
`
`(Minos
`
`rettd
`
`is
`the cradie. Once contact
`side of
`established, the computer transmitsa,
`first frame, which requires the user to
`enter a user number. When this has
`been done Viewdata offers the first
`index (shown in the Februaryissue,p. .
`32).
`The action is now transferred tothe
`keypad. Onthis the user keys-in his user
`number and any further responses.
`Suppose the user wishes to obtain
`information about entertainment acti-
`vities for a given day of the week. The
`
`user may enter the entertainment page
`direct by keying *3230¢. An example of
`one of the pages in the entertainment
`sequence was Fig. 6 in the February
`issue. In later models of the terminal,
`use is made of the calling key on the
`keypad. This calls the Viewdata com-
`puter automaticaliy and switches over
`to the modem without
`the user’s
`intervention. The keypad may then be
`used as previously.
`' The design philosophy of Viewdata
`which has been dealt with in the first
`~~Batabanks
`
`Fig. 1. Overall picture of connections in
`Viewdata, showing the telephone
`
`system at the top and the home and
`office terminal at the bottom.
`
`Viewdata
`
`
`computer
`Telephone
`
`
`exchange
`
`
`Strowger,
`crossbar"
`or TXE
`exchanges
`
`
`
`
`
`Fig. 1 gives an overall view of aViewdata
`connection. The hometerminal, shown
`at the bottom left hand side, comprises a-
`domestic television set, a telephone
`instrument, a Viewdata adaptor and a
`keypad. The actual assembly is shown
`in Fig. 2. Two types of keypads proposed
`are shown in Figs. 3 and 4. The basic
`keypad is Fig. 3; this provides the ten
`numerals, *and =z symbols and keys for
`automatic dialling, if installed. Fig. 4 is
`an alphanumeric keypad. This contains
`in addition to the above, the complete
`uppercase alphabet, punctuation marks
`and symbols like £,%,/, arithmetic and
`algebraic symbols and eursor’ control
`characters. A typical Viewdata terminal
`for the office,
`tne Viewdataphone,
`is
`shown schematically at
`the bottom
`right hand side of Fig. 1. This consists
`of
`a Viewdata terminal and a
`self-contained telephone instrument. A
`typical Viewdataphone was shown in
`the March issue. The Viewdata com-
`puter is shown at
`the top of Fig. 1,
`notionally connected to a variety of.
`data banks,either direct or through the. -
`switched telephone network.
`/
`As mentioned in the February issue’
`communication between the terminal
`enmeee!
`
`and the Viewdata computeris at a rate
`Other
`1200 bits /sec
`
`customers
`of 1200 bits/s from computer to termin-
`
`al and 75 bits/sin the opposite direction.
`Moredetails of this arrangement will be
`given later.
`:
`In order to establish a connection to
`the Viewdata computer the user dials
`the telephone number of the computer
`as for anormaltelephonecall. When the
`connectionis established the computer
`generates a high pitched tone (fre-
`/quency 1300Hz).which is heard in the
`telephone receiver. The user
`then
`presses a button marked “data” on the
`telephone set, which switches the
`telephoneline from the telephoneset to
`a modem (modulator-demodulator).
`Thetelephonereceiveris then set by the
`
`Viewdata
`
`.
`
`adaptor Fz
`
`
`
`
`—
`
`1
`
` | 4
`
`iene
`
`Local telephone
`exchange
`
`75 bits/sec
`
`LY
`
`EQUIPMENT iN THE OFFIC!
`
`PMC Exhibit 2068
`PMC Exhibit 2068
`Apple v. PMC
`Apple v. PMC
`IPR2016-00753
`IPR2016-00753
`Page 3
`Page 3
`
`

`

`
`
`
`& Fig. 2. Home terminal for Viewdata,
`with television set, telephone (right)
`‘and keypadon the table.
`
`66
`
`two parts of this article referred to the
`need to keep the cost of Viewdata down
`- to very lowlevels, both on the terminal
`side and on the computer usage side.
`Indeed, uniess the cost of using the
`computer facility is kept substantially
`below that of using current computer
`time-sharing systems, the whole project
`may not becomeviable: This therefore -
`postulates the use of a distributed
`computer system, so arranged thatthe.
`majority of users may have access to a
`nearby computercentre, at the cost of a
`local telephone cali for the connection
`plus a correspondingly modest charge
`for the use of the computer and the
`information provided.
`The resulting networkis typically as
`shownin Fig, 5. Users are within a local,
`cali distance of their computercentres,
`shown as rectangles. A cluster of local
`computer centres is grouped under the
`control of a regional centre for the
`purpose of data gathering and distribu-
`tion. A national data centre controls the
`operation of
`the whole system and
`distributes to each regional centre new
`‘information, news and data updates.
`Regional centres also accept informa-
`tion of regional or local interest and
`distribute this to the local centres.
`
`A Fig.3. Basic keypad used in a Viewdata
`terminal,providing ten numerals and a
`few other keys.
`
`carried out over the past twa years from
`a large numberof centres in the UK and
`on the Continent. In all these tests the
`public switched telephone network was
`used to connect up to the experimental
`Viewdata system based at Martlesham,
`near Ipswich, and transmission diffi-
`culties have been very rare.
`Thecharacter codes used for View-
`data and teletext are also identical,
`
`Regional data, news
`
`Regicnal
`centre
`
`TheViewdata terminal
`‘Display format. The display format of:
`Viewdata is identical with that of
`teletext,i.e. a page consists of 24 rows of
`40 characters each, each character
`being generated by a5 x 7 matrix with
`upper and lower case, character round-
`ing, graphics symbols and colour. Thus:
`a great deal of the electronics in a
`terminal may be common to Viewdata
`and teletext,
`the differences being
`primarily concerned with the addition-,
`al functions needed in Viewdata, the
`different modes of transmission appli-
`cable to these two syslems and the
`different contraints appertaining to the
`different communications media
`involved.
`_~ In the case of Viewdata the data
`enters the terminal via the telephone
`line at relatively low speed, and, as the
`probability of data corruption is quite
`low,little is needed for the purpose of
`error detection and correction. Indeed,
`extensive Viewdata tests have been
`
`
`
`|
`Local
`
`computer 3
`
`
`Local
`
`
`computer 2
`
`
`
`Local
`
`computer 1
`
`
`
`Wireless World, April 1977
`
`except for the actual codes transmitted
`over the line, where a slight change is
`made to comply with International
`Standards Organization recommenda-
`tions.
`The tabie of codes used for Viewdata
`is shownin Figs. 6, 7 and 8. Fig.6 shows
`the joint Viewdata and teletext codes
`for alphanumeric characters only. This
`differs from earlier versions in the
`following characters:
`
`>
`
`Column
`5
`5
`5
`5
`6
`7
`7
`7
`7
`
`Row
`il
`12
`13
`15
`0
`ll
`12
`13
`14
`
`Was
`
`C
`\
`7
`-
`
`t
`i
`\
`—
`
`Is now
`—
`%
`4
`z
`-
`%
`II
`%
`+
`
`‘
`
`Note: Thetop,left-pointing, arrow is used as
`an assignment statement; the lower, right-
`pointing, arrow means “go to’; and the sign =
`is used as a terminator and for special
`functions. Note also that
`the arithmetic
`operator X (multiply) used in Viewdata is
`shown as x (iower case x), while the minus
`sign (—) is code 2/13 and the exponentiation
`sign is code 5/14 shown as ¢.
`,
`Fig. 4. More elaborate, alphanumeric,
`
`ww keypad with a variety of other symbols.
`
`Y Fig. 5. A distributed Viewdata network,
`showing local computers, regional
`centres and national data centre.
`
`
`National data,
`news
`
`National
`data
`
`centre
`
`
`
`Local
`
`
`computer 1
`
`
`Regional
`
`centre
`
`Regional clusters
`100,060 customers each
`
`Local
`computer 2
`
`PMC Exhibit 2068
`PMC Exhibit 2068
`Apple v. PMC
`Apple v. PMC
`IPR2016-00753
`IPR2016-00753
`Page 4
`Page 4
`
`

`

`
`
`“
`|
`=
`
`Wireless World, April 1977
`Bi
`
`.
`
`
`
`”
`=~
`=
`
`~
`:
`
`q
`/
`#
`
`
`>
`
`a
`
`
`
`
`
`}
`|
`
`.
`
`~ .\ .67
`
`oe | [oY
`_
`“De
`co.
`ao
`
`——+|
`bs
`9
`
`
`
`Bi Bits|bybgbsb,b3b,b,; Oa ta
`
`
`
`
`
`:
`_
`:
`
`
`
`
`
`
`
`. wey||B!700 0j1@ 0-000 (NUL) Ho
`
`
`
`
`
`s &
`.
`graphics
`°
`T/AIQla
`alpha”
`
`
`~
`4s a .
`0
`2;BIRIb
`red”
`140
`red
`T alphao
`graphics
`9011
`3/c]Sie
`
`
`“green
`A A
`40100
`4|/0}T]4a
`green
`a i :
`
`
`4
`,
`alpha”
`graphics
`.
`
`9
`O41
`BS
`,E| ule
`yellow
`yellow
`sal a
`x 5 .
`“Fl E|
`[graphics
`or10
`SF yvit
`alpha”
`:
`
`blue
`0114
`7\olwlg
`_ blue
`i E
`
`
`graphics
`1
`o°0
`Bi H]|X Th
`alpha”
`|" magenta
`1001
`9|l]y]i
`magenta
`E E
`E f E
`
`101 alpha"-graphicssludzi
`
`
`
`cyan
`°
`,
`ye
`cyan
`a z :
`J x ie
`raphics
`alpha
`~
`.
`:
`4011
`3|/ Ki]
`Ion _S
`hi
`
`Sivbite
`47100
`<jlLiwiet
`white
`FIR
`E E
`”
`4
`o1
`=|M |-»/[m
`conceal
`:
`
`
`display
`4110
`>[N]t]n
`flash
`| &
`il i
`:
`
`:
`contiguous
`141414
`2/O|T]o
`
`
`
`: |“Grapnies”|AM |steady fa)
`
`separated
`Fig. 6. Codesfor alphanumeric characters only,
`abo
`aa |
`ay a
`nd
`box
`t
`t
`.
`
`
`°
`graphics
`as used in both Viewdata and teletext.
`:
`
`
`start box
`(ESC)
`ala
`A a:
`
`normal
`black
`i
`
`
`background i #
`height
`a a :
`
`
`new
`a a F
`double
`k F
`background
`height
`,
`
`hold
`;
`
`raphics
`(SO)
`ener
`. a #
`al
`id
`release
`
`
`a Ez i ai aI
`graphics
`($1)
`x
`=
`Fig. 7, Codes for graphics used:in: teletext.
`:
`
`
`
`
`
`:
`
`:
`
`:
`
`
`
`:
`:
`.
`Fig. 7 shows the graphics and control
`characters use in teletext, as at Sep-
`tember 1976*, the conventions being as
`before,that is:
`.
`1. All character rows start
`in the
`4
`steady”, “alphanumeric white” and
`“unboxed” condition without control
`characters.
`2. Control characters shown are dis-
`played as spaces, but control whether
`alphanumeric or graphic characters are
`displayed andwhatcolouris used.
`3. Alphanumeric characters in columns
`4 and5, ie. all of the upper case letters
`5
`-
`by
`jo
`fo
`o
`lo
`1
`1
`4\4
`
`
`and a few others, may be displayed next Dg|oO 0 1 [4 a> °| 1 1
`
`
`
`
`
`
`Dg
`9
`af
`Of
`7
`9
`1)
`9
`1
`to graphic symbols without an inter-
`4
`vening space,
`:
`Col
`:
`.
`“¢
`
`
`
`
`
`
`
`While the intervening space conven-
`FS
`eB SK 8P
`271) Row
`;
`tion following a control character ‘is
`900 ol
`oI
`NUL
`He [o
`[
`:
`ce
`ey
`|
`
`“
`ne
`;
`al
`’
`essential in teletext, it has been accept-
`
`mq & ana
`ed in Viewdata for the sake of unifor-
`0001
`1
`=
`3
`graphics .
`
`;
`mity, although it is not reaily essential
`bi
`|S a aereen
`and imposes undesirable constraints on
`0010)
`2
`green
`cu
`Fy
`the page format.
`h
`.
`graphics
`alpha’
`Additional control characters have.
`OO11)
`3
`2a = yellow
`yellow
`x
`a
`,
`pha’
`graphics _
`]
`.
`A
`yea:
`1
`recently been added to teletext
`to
`alpha”
`hi
`provide enhanced display facilities. The.
`o190)
`4
`Kj
`EB
`blue
`blue
`g
`i
`“intervening space’? convention is
`o10:7)
`5.
`alpha”
`graphics
`c
`somewhat modified and made less
`B))
`IB)
`Arosenta | Magenta
`c
`E
`.
`.
`Cc
`.
`6
`-lortoj}
`onerous, althoughnotall its undesirable
`ie
`rf
`alpha?
`arapnics
`g
`g
`effects are eliminated.
`ya
`ti
`7
`aria)
`i
`~
`The new control characters, which
`PUB) te.
`(ene |
`E
`:
`may be applied equally in Viewdata are
`conceal
`in four groups: a 8|BS]1000) CAN ea a flash display Aa a
`
`
`
`
`
`
`
`
`Contiguous/separate graphics.Codes 1/9
`.
`contiguous
`
`
`
`
`
`
`
`
`and 1/10 in teletext, 5a/9 and 5a/10 in |Grapnics”|Alroot) 9 AT Fa) HR] steagy a
`Viewdata. This provides the choice. of
`:
`separated
`
`
`
`
`graphics symbols filling the whole of a 1|LF al a end box.|"graphics1910) Hi a
`
`character rectangle, or only six discrete and
`:
`:
`
`
`
`
`
`
`“separate dots. PE|| start poxtort} nu fvt} esc Al a
`
`Normal height/double height. Codes 0/12 ©
`,
`normal
`biack
`
`
`
`and 0/13 in teletext, 4a/12 and 4a/13 in 2|FF1100) mi # height background | a
`
`
`
`Viewdata. This provides for the optional
`.
`double
`new
`display of alphanumeric characters in the
`tes 13)
`~
`-
`CR
`& E height
`background hh
`i
`standard. size, Le. within the normal char-
`hold
`.
`4410
`14
`eee a -
`graphics
`qi
`a
`“Broadcast Teletext Specification. Published
`IS2
`release
`jointly by the Broadcasting Corporation, Indepen-
`1114 i ,
`a EF L
`graphics a a
`.
`dent Broadcasting Authority and British Radio
`.
`.
`Equipment Manufacturers Association.
`Fig. 8. Control and graphics codes used in Viewdata.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`. 2a|3a; aac B b, bgDsb, b3b,b ° 1 4a 5a 6a 7a
`
`
`:
`.
`.
`
`
`
`
`
`
`
`
`
`DC
`| DCe
`DCs,
`DC4
`
`,
`
`;
`leno
`
`,
`
`
`
`
`
`PMC Exhibit 2068
`PMC Exhibit 2068
`Apple v. PMC
`Apple v. PMC
`IPR2016-00753
`IPR2016-00753
`Page 5
`Page 5
`
`
`
`
`
`:
`
`

`

`68
`
`Wireless World, April 1977
`
`acter rectangle or stretched vertically to
`double height, the width. of each character
`and the intervening spaces between char-
`vacters remaining the same.
`
`‘and 1/15 in teletext, 5a/14 and 5a/15 in
`Viewdata. This allows a limited range of
`abrupt display colour changes in a row
`whereas normallythere is at least one space
`between rectangles with different display
`colours in the same row.
`
`QO
`
`1
`
`:
`
`oO
`
`oO
`
`v1
`
`1
`
`Cursor. The cursor in Viewdata is a
`symbol which shows up on the display
`as a bright rectangle,filling’the space of
`an upper case alphabetic character. It
`may be switched on andoff, as required.
`Black background/new background. The
`by a switch on the terminal or on-the
`background colour of the character rectangle
`is normaily black. Whenever:
`the new
`keypad, or by remote control from the
`‘background control character 1/13 in tele-
`The graphics and control characters
`computer. It may also be moved any-
`text or 5a/13 in Viewdata occurs, the display
`where over the display either manually
`in Viewdata are show in Fig 8, but
`colour then obtaining is adopted as the new
`before these are looked at in detail, the
`by using special keys on the keypad or
`backgroundcolour.
`by remote control from the cornputer.
`use of a cursor in Viewdata shouldfirst
`Hold graphics/Release graphics. Codes 1/14
`The cursor has many functions.
`beexplained.
`
`
`“4 Fig: 9. Complete
`°
`3
`7
`7
`;
`;
`set of Viewdata
`(-—— Q_9}4 ° 1 _| codes: columns
`
`
`
`
`
`
`Ee
`:
`pot
`colett
`
`
`
`
`
`
`
`
`
`
`
`
`Bits 3|3a] 4a|5 7|)7a]by bgbsb, bbb, 1 2{ 2a] 4 5a 6] éal 2% 80, 6aand 7a
`
`
`
`
`
`
`go00}; _ ~|Hie|@o jNuL sere} olf @ . P Ba for the can
`
`
`
`
`
`
`
`
`
`-° |ooo1 Der|P11)1 a Bla "alpha? Q graphics al Agia | controls.
`
`
`
`
`
`
`
`
`
`
`co10| 2|fA) 62 DC. || Al alpha? R grapnics olmilr @
`
`
`
`
`
`oo11| Deg|£ c|ame «| Hls|&3 31 ff s |View
`
`
`
`
`
`
`
`o100| 4|Bf T|ofapnics ola wit4 Dou $1] oy apne"
`
`
`
`
`crot|
`5
`jena of |B]
`s
`BB)
`=| see.
`ju
`lemme.
`|e
`fig] |g
`e140]
`s
`ele jm@pe
`fame
`fv mame
`tag) al
`
`
`
`
`parta} 7 Ble|nw kee7 VB) fo | :
`
`
`tooo; fas| can|¢ | Able|i] xi¥s x flash Kee n| Gey)
`
`
`
`
`
`
`
`
`
`4oo1} steady|y {contiguous|i|Mil y|i9 |aHt >| filo) & “]
`
`
`
`
`
`
`
`
`
`4010] 7|LF *|A]:|Bi] s|end box|2 i|Ay: aseparated
`
`
`
`
`
`
`tort] esc|+|AR) s | K|start boxnm elvr] |< el Aye ¥ diceramsofa) a
`
`T1900/
`| FF
`>|) <| mie "Relgnt
`Yo BSground)
`| mm)
`id ewed(b)
`4
`
`
`
`
`
`4401] m| i|% i12 [cr ~|Rl= Fie Oeee Oekground G teletext
`:
`.
`ermin
`110]
`14
`*
`ml > a N
`'
`poaphics
`n
`ql + a
`showingvideo
`“home|
`4111
`15
`/ x .? # O°
`tt rerapaics
`° a i i
`thetelevisionset
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`INTERFACE BOARD
`INTERFACE BOARD
`
`:
`
`COLOUR TV RECEIVE
`
`Electronic.
`video
`change-over
`switches
`
`Outputs
`
`VIEWDATA _
`DECODER
`
`itch control
`
`(@)
`
`Electronic
`video
`change-over
`switches
`
`Outputs
`
`TELETEXT
`DECODER
`UNIT
`
`(P)
`
`
`
`PMC Exhibit 2068
`PMC Exhibit 2068
`Apple v. PMC
`Apple v. PMC
`IPR2016-00753
`IPR2016-00753
`Page 6
`Page 6
`
`

`

`
`
`Wireless World, April 1977
`ee
`
`
`
`TELETEXT
`DECODER UNIT
`
`()
`VIEWDATA
`_ DECODER UNIT
`
`Line input
`
`69
`
`1/8
`
`1/9
`
`ESC.
`
`1/4 DC4: Device control 4, Used to switch
`‘off both tape recorder and hard
`copy unit
`CAN Cancel. Used to delete line of
`character. This codeis used only
`from terminal to computer
`Escape. Used to indicate to
`terminal that the character |
`following is from anotherset of
`control codes(in this case the
`control code set 2a to7a of
`colours or graphics)
`Home. Returns cursor to
`character position 1 on screen
`(top left hand side)
`
`1/10 IS2
`
`Graphies characters. The graphics’ and
`colour control characters for Viewdata
`are shownin Fig. 8 columns2a,3a, 6a, 7a
`for graphics and 4a and 5a for the
`controls. For line transmission the
`control characters of 4a and 5a are
`always preceded with ESC (cade 1/11).
`On. receipt of this code the terminal
`reverses the polarity of bit 7 from 1 to 0,
`thus restoring compatibility with tele-
`text and places the charactersin store.
`The graphics characters in columns
`2a, 3a, 6a and 7a are fully compatible
`with teletext and are treated in the same
`way whendisplayed. The compiete set
`-of Viewdata codesis shownin Fig. 9.
`
`Fig. 11. Block diagrams of (a) a teletext
`terminal and (b) a Viewdata terminal,
`showing rf. (u.h.f.) connections to the
`television set.
`
`Block diagram of terminal. A block
`diagram of a Viewdata terminal
`is
`shown in Fig 10 (b). This shows the
`interconnection between the Viewdata
`Basically it gives a visual indication of
`decoder and the video amplifier of the
`the position on the screen at which the
`colour tv receiver. An interface board
`next character sent by the computer
`contains the electronic switch which ,
`will be displayed. When the computer
`provides
`the changeover
`from tv
`sends a new pageof information to the
`reception to Viewdata. The input to the
`terminal,
`it first sends a code which
`puter and user which resembles a
`Viewdata decoderunitis, of course, the
`returns the cursor, whether visible or
`pointer (but more aboutthis later).
`Control characters in columns 0 and 1
`‘telephone line. By contrast Fig 10 (a)
`not on the display,
`to the “home”
`showsthe teletext decoder connections
`position which is at the top left-hand
`must comply with 1SO7for line trans-
`(Wireless World, December 1975, pp.
`mission and so far 15 have been
`side of the display. Thereafter, as each
`563-566). The input
`to the teletext
`character
`is entered,
`the cursor is
`allocated. Additional characters in the
`decoderis obtained from thei-f. input.
`moved one character position to the
`same columns may be allocated in
`future as more facilities are included.
`~
`Fig 11 showsasimilar set of connec-
`right. The position of the cursor,
`The control characters wnicn have so
`whether this is switched on or off, is
`tions where the entry to the television
`set for display purposes is the aerial’
`recorded by two counters, a character
`far been allocated in the experimental
`socket of the tv receiver. In Viewdata
`counter and a row counter, which
`system undergoingpilottrials are:
`only (b).a u.hf. modulator has to he
`maintain at all times a knowledgeof the
`Col/ Name Function
`added, whereasforteletext (a) an’
`row
`:
`‘position at which the next characteris
`additional tuner andif. strip must be!
`to be displayed (and entered on
`0/1 NUL None-used fortiming purposes .
`provided. Hence the considerably
`memory). Thus we talk of the cursor as
`0/5 ENQ Code sent by computer.to’
`sterminalto initiate automatic:
`greater attraction of a built-in decoder
`it it were a real entity, whetheror notit.
`in the case of teletext.
`terminalidentification
`is displayed.
`Back-space, Moves cursor one
`By moving the cursor by meansof the
`character position to left
`controls available (see below),
`the
`HT:+~ Horizontal
`tap. Moves cursor
`computer may position it to where the
`‘~One .characterposition to right
`next characteris to be entered. Thusit is
`0/10 LF
`Line feed. Moves cursor oneline
`position down
`not necessary to sendaseries of spaces
`where one or more blank lines are
`0/11 VT
`Vertical tab. Moves cursor one
`line position up
`required, or where a row of charactersis
`shorter than the full length of the line.
`Form feed. Erases screen and
`moves cursorto top left hand
`* The cursor also enables the computer to
`side of sercen (position 1)
`The journal you like
`overwrite a portion of a display without
`Carriage return. Moves cursor to’
`having to first erase and retransmit the
`Wireless World’s average circulation
`firstposition on sameline
`“last year. was up 4,604 copies to 69,220
`whoie page.
`‘|
`Combinations
`per month, according to the Audit
`The cursor may also be used at-the
`Bureau of Circulations. Overseas
`il pel Device
`of these char-.
`control i
`terminal for editing purposes, e.g. when
`acters will be!
`readers, in countries from the USSR and
`composing messages or doing calcula-
`‘Device
`1/2 DC2
`used to switch
`USA to the Falklands and Seychelles,
`tions, or to point at a feature of the
`: control 2{. on-tape recor-.:
`
`bought21,000 of these. Onaverage, for
`ders and‘hard: ">!
`display it is desired to manipulate. In
`43 pc3 Device.
`the past eight years 200 more readers
`control 3
`copy
`devices
`this context the cursor is a powerful .
`remotely
`- communication channel between com- |
`
`RS
`
`0/8
`
`0/9
`
`0/12 FF
`
`. 0/18 CR
`
`:
`
`-
`
`(To be continued)
`
`
`
`have joined ourcirculation each month.
`
`
`
`Page 69
`
`PMC Exhibit 2068
`PMC Exhibit 2068
`Apple v. PMC
`Apple v. PMC
`IPR2016-00753
`IPR2016-00753
`Page 7
`Page 7
`
`