MENDAPATKAN TELETEXT

<p class=”MsoNormal”><b><span style=”background: #33cccc none repeat scroll 0pt 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-size: 10pt; font-family: ‘Verdana’,’sans-serif’; color: navy”>So what is teletext? </span></b><span></span></p>
<p class=”MsoNormal” style=”text-align: justify; text-indent: 0.5in”><span style=”font-size: 10pt; font-family: ‘Arial’,’sans-serif'”>Teletext consists of pages of information, such as news and sport, which are viewed on a television set capable of viewing these pages. Its roots lie in the 70s, when the BBC and Oracle started the first test services. The actual teletext pages are broadcast in a hidden part of the television signal (the Vertical Blanking Interval), and decoded by the television. Teletext pages are accessed by a 3-figure number; on most channels, the front page is on page 100.</span></p>
<p class=”MsoNormal” style=”text-align: justify; text-indent: 0.5in”><span style=”font-size: 10pt; font-family: ‘Arial’,’sans-serif'”>As well as news and sport, teletext contains financial information, such as the latest share prices, recipes, entertainment listings, holiday adverts, cinema, music and TV reviews, back-up information for certain TV programmes, and themed magazines, e.g. for kids. Teletext also broadcasts subtitles (better known in the United States as ‘closed captions’) on certain programmes, and news flashes which are overlaid on top of the TV pictur</span><span style=”font-size: 10pt; font-family: ‘Verdana’,’sans-serif'”>e.</span></p>
<p class=”MsoNormal”><span style=”font-size: 10pt; font-family: ‘Verdana’,’sans-serif'”> </span></p>

<ul type=”disc”>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>BBC Two as part of their ‘traditional’ analogue transmissions. The      BBC Two service contains slightly more information – as a result, it’s a      bit slower. For the time being BBC News 24 also broadcasts a special      version of Ceefax via digital satellite and some analogue cable systems,      which contains the news and sport stories for all regions. BBC      Parliament’s service is named Parliafax. Apart from that the new digital      services do not now carry teletext. Instead they carry the new high      resolution ‘interactive’ BBCi service.</span></li>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>The service named <b>Teletext</b> is broadcast on analogue ITV and      Channel 4. The service itself is independent of those channels, and is      operated by <a href=”http://www.teletext.co.uk/”>Teletext Ltd.</a>, which      is partly owned by Associated Newspapers, who own the Daily Mail. ITV and      Channel 4 are legally obliged to carry Teletext on their signals by the      Broadcasting Act 1990. <b>Teletext</b> replaced <b>Oracle</b> at the      beginning of 1993, after they were awarded the new Public Teletext Service      license by the <a href=”http://www.itc.org.uk/”>Independent Television      Commission</a>. Channel 4 is also on digital satellite – on this      platform, Channel 4 doesn’t broadcast Teletext as they’re not obliged to.</span></li>
<li class=”MsoNormal”><b><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>5 Text</span></b><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> broadcasts on Channel 5. As with Teletext, it      is theoretically independent of its hosting channel. 5 Text’s feel is very      similar to Sky Text, as it is operated by Sky Five Text Ltd., owned by <a href=”http://www.sky.co.uk/”>BSkyB</a&gt; and <a href=”http://www.channel5.co.uk/”>Channel 5</a>. Although the carriage of      5 Text is legally the same as Teletext, it is carried on digital      satellite, obviously because of the owners’ interests in it. 5 Text is      BSkyB’s only foothold in analogue terrestrial TV.</span></li>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><a href=”http://www.itv.co.uk/newpress.php3″>ITV</a&gt;, <a href=”http://www.channel4.com/c4info/frame_c4info.cfm”>Channel 4</a> and <a href=”http://www.channel5.co.uk/green/facts/index.html”>Channel 5</a> all      broadcast their own pages which are distinct from the main services.      Channel 5’s ancillary service, however, is named after the main service      which they part-own, and is similar in look. ITV’s ancillary service is      run by each ITV franchise individually, although there are certain pages      which are shared between regions. As it’s often named after the ITV      company operating it, such as ‘Meridian Text’ or ‘Carlton Plus’, it’s      generally referred to as just ‘text’ when mentioned on-air. ITV’s own      service is on page 600, C4’s ancillary service – <b>4-Tel</b> –      on page 300, and Channel 5’s 500. The latter two are also carried via      digital satellite (which ITV isn’t on).</span></li>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Most other channels carry teletext services, with varying degrees      of success. Some a little more than a TV listings page, whereas others      provide detailed background information on all programme</span></li>
</ul>
<p class=”MsoNormal” style=”text-align: justify; text-indent: 0.25in; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><a href=”http://www.intelfax.co.uk/”>Intelfax</a&gt; are the company commissioned to provide 4-Tel and most ITV ancillary services, as well as the services on many other channels. <a href=”http://www.datadesign.co.uk/”>Data Design</a> are another teletext provider, whose services include MTV-Text. Ceefax is a product of BBC News and Current Affairs. I’m not sure who operates SkyText and the main and ancillary 5 Text services</span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”q”><a title=”where” name=”where”></a><b><span style=”background: #33cccc none repeat scroll 0pt 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-size: 10pt; font-family: ‘Verdana’,’sans-serif’; color: navy”>Where can I get teletext? </span></b></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>You need </span></p>

<ul type=”disc”>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>A      teletext-capable TV, or a computer with a teletext or TV card </span></li>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>A      station broadcasting teletext. All of the UK’s analogue terrestrial      channels broadcast teletext; some cable and satellite services also carry      teletext services. Digital terrestrial TV does not.
</span>
<ul type=”circle”>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>There are also various teletext-to-Web       gateways – that is, you view the teletext pages in your Web browser       over the Internet.
</span></li>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>The BBC don’t broadcast Ceefax on the       Web. However, they do license parts of the service, such as the weather,       from other companies; this same information may be licensed by the BBC or       others for their Web sites. As I see it, though, the BBC have no excuse       for not publishing the parts of the service which aren’t licensed –       for example, the ‘TV Links’ section, which provides backup information       for BBC programmes, often contains information which doesn’t exist on the       BBC’s Web site.</span></li>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Similarly,       the majority of Teletext’s pages aren’t on the Web. They do, however,       publish their <a href=”http://www.teletext.co.uk/”>holiday adverts</a>,       as well as flight arrivals.
</span></li>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>For a list of Web sites carrying       teletext, see the <a href=”http://teletext.mb21.co.uk/live.shtml”>teletext       live</a> page. It strikes me as strange that whilst newspapers are       widespread on-line, that none of the main UK services, which are       transported in electronic form to start with, are available</span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif'”>.</span><span style=”font-size: 10pt; line-height: 150%”> </span></li>
</ul>
</li>
</ul>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”line-height: 150%”><b><span style=”background: #33cccc none repeat scroll 0pt 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif’; color: navy”>But nobody reads teletext, it looks crap” some might say </span></b><span></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif'”><span>          </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>True, it does look crap. The thing is, most people don’t care – but the majority of people just don’t notice its limitations. The computer press often likes to bash teletext, branding it defunct because of its looks. This is in spite of the fact that over 22 million people look at teletext every week (<a href=”http://www.itc.org.uk/documents/upl_155.doc&#8221; title=”ITC’s annual review of Teletext, 1999″>ITC</a>), that it needs no technical expertise, and that it’s free of subscription and phone charges.</span><span style=”font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif'”><span>          </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>The blocky graphics have been addressed. ‘HighText’ – teletext level 2.5 – provides more colours and simple, but smoother, graphics. In the UK, TV manufacturers and teletext providers have both ignored it in a chicken-and-egg scenario. Not only that, but if teletext providers used all the extra features, it’d slow the service down. And now that digital TV has launched in the UK, it looks unlikely that the providers will invest anything into updating the analogue teletext services.If your TV is newish, it may support HighText – Arte, ARD, ZDF or 3sat (on Astra 1.. and others?) have enhanced some of their page</span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif'”>s</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”> </span></p>
<p class=”MsoNormal”><a title=”slow” name=”slow”></a><b><span style=”background: #33cccc none repeat scroll 0pt 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-size: 10pt; font-family: ‘Verdana’,’sans-serif’; color: navy”>Why is teletext so slow? Why can’t I just flick through the pages? </span></b><span></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif'”><span>          </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>When you key in a page number to look at, the broadcaster would have to know what page you’ve just requested so that they can broadcast it. Of course, they don’t know this – there’s no way of feeding your page number back to the broadcaster (although this is possible with cable). So the solution is to broadcast <i>all</i> the pages, rotating them around (a data carousel). Once you have keyed in a number, your TV sits around, waiting for the page to be broadcast so it can show it to you. This is why the services on channels which broadcast many pages are slower.</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Whether you can flick through the pages or not depends on how much memory your TV has, and how many pages have actually been broadcast since you tuned in. When viewing teletext on a computer, it is common for the software to cache many more pages than possible on a television. As a result, after have tuned to a channel for half a minute or so, it is possible to flick through the majority of pages.</span><span style=”font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal”><b><span style=”background: #33cccc none repeat scroll 0pt 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-size: 10pt; font-family: ‘Verdana’,’sans-serif’; color: navy”>What is the future of teletext? </span></b><span></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Verdana’,’sans-serif'”><span>          </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Digital television has ‘digital teletext’. Despite the name, the only thing common to ‘analogue’ teletext is the fact that the viewer looks at information on the TV screen. The methods used to broadcast and decode it, as well as the way it looks, are much removed.</span><span style=”font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Some channels on SkyDigital, the UK’s digital satellite operator, carry analogue teletext despite the promise of digital teletext. Sky’s own-brand channels carry an expanded version of SkyText, although it directs viewers to the Sky Electronic Programme Guide instead of carrying TV listings.</span><span style=”font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Channels on the UK’s digital terrestrial channels </span><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>don’t</span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> carry analogue teletext. This was due to a decision by <a href=”http://www.dtg.org.uk/”><span style=”line-height: 150%”>The Digital Television Group</span></a> (DTG), who decided that such things were unnecessary. In the long term, this is probably true.</span><span style=”font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Teletext Ltd. will be provides a service on channel 9 of digital terrestrial television with the BBC Text on channel 10.</span><span style=”font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>To complicate things for the providers of digital teletext, the systems opted for by Sky and DTG are different. Whilst DTG decided to use <a href=”http://www.mhegcentre.com/”><span style=”line-height: 150%”>MHEG-5</span></a>, which is an ISO standard, Sky decided on <a href=”http://www.opentv.com/”><span style=”line-height: 150%”>OpenTV</span></a>. OpenTV is a proprietary ‘solution for digital interactive receivers’. Teletext has a <a href=”http://www.digital-teletext.co.uk/home.htm”><span style=”line-height: 150%”>demo of Digital Teletext</span></a> on their web site; the BBC also has some information on <a href=”http://www.bbc.co.uk/digital/html/television/1_interactive.shtml&#8221; title=”BBC Interactive Services on BBC Digital”><span style=”line-height: 150%”>their digital site</span></a> and in <a href=”http://www.bbc.co.uk/rd/pubs/papers/pdffiles/DTV150399rpm.pdf&#8221; title=”Where is it and where is it going? (BBC Research &amp; Development)”><span style=”line-height: 150%”>a paper</span></a> (in PDF format).</span><span style=”font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal”><a title=”reveal” name=”reveal”></a><b><span style=”background: #33cccc none repeat scroll 0pt 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; font-size: 10pt; font-family: ‘Verdana’,’sans-serif’; color: navy”>How are the images on your site saved?  </span></b><span></span></p>
<p class=”MsoNormal” style=”margin-left: 35.7pt; text-align: justify; text-indent: -17.85pt; line-height: 150%”><!–[if !supportLists]–><span style=”font-size: 10pt; line-height: 150%; font-family: Symbol”><span>·<span style=”font-family: ‘Times New Roman’; font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal”>         </span></span></span><!–[endif]–><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Since the early 1990s I have been using either an <a href=”http://www.opt.com/”><span style=”line-height: 150%”>Optimum Tecnology</span></a> OPT-III PC teletext card and a <a href=”http://www.hauppauge.com/hcw/index.htm”><span style=”line-height: 150%”>Hauppauge Win/TV pci card</span></a> using VTplus software. This allows copy and export in BMP format. I then use Paintshop Pro to produce GIF files, which are typically around 5-6kb in size per frame. Some images are larger, being animated GIFs consisting of multiple sub-pages.</span><span style=”font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”margin-left: 35.7pt; text-align: justify; text-indent: -17.85pt; line-height: 150%”><!–[if !supportLists]–><span style=”font-size: 10pt; line-height: 150%; font-family: Symbol”><span>·<span style=”font-family: ‘Times New Roman’; font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal”>         </span></span></span><!–[endif]–><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Some of images are taken from pages broadcast live on television or recorded onto VHS tape and captured using the Hauppauge card. These images are of poorer quality due to the state and age of the tapes used and not due to any problem with the hardware.</span><span style=”font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”margin-left: 35.7pt; text-align: justify; text-indent: -17.85pt; line-height: 150%”><!–[if !supportLists]–><span style=”font-size: 10pt; line-height: 150%; font-family: Symbol”><span>·<span style=”font-family: ‘Times New Roman’; font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal”>         </span></span></span><!–[endif]–><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>It is sometimes possible to decode teletext data from old S-VHS recordings and we are currently appealing for the loan of any <a href=”http://teletext.mb21.co.uk/appeal.shtml”><span style=”line-height: 150%”>old S-VHS recordings</span></a> you might have which might yield such data.</span><span style=”font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”margin-left: 35.7pt; text-align: justify; text-indent: -17.85pt; line-height: 150%”><!–[if !supportLists]–><span style=”font-size: 10pt; line-height: 150%; font-family: Symbol”><span>·<span style=”font-family: ‘Times New Roman’; font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal”>         </span></span></span><!–[endif]–><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Some of the teletext pages have been donated by others, the full roll of honour is on the <a href=”http://teletext.mb21.co.uk/contributors.shtml”><span style=”line-height: 150%”>credits page</span></a>. Some of these were captured using a BBC Model B computer with the Acorn Teletext Adapter, produced in conjunction with the BBC. We have taken the raw teletext files, in Acorn TFS format or !Hearsay format and converted these into a format readable by VTplus using custom software developed by Darren Meldrum using BBC Basic(86) on a Pentium 133 under Windows 95.</span><span style=”font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”margin-left: 35.7pt; text-align: justify; text-indent: -17.85pt; line-height: 150%”><!–[if !supportLists]–><span style=”font-size: 10pt; line-height: 150%; font-family: Symbol”><span>·<span style=”font-family: ‘Times New Roman’; font-style: normal; font-variant: normal; font-weight: normal; font-size: 7pt; line-height: normal”>         </span></span></span><!–[endif]–><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Some pages have been reconstructed from printed versions. In these cases Richard Russell’s excellent <a href=”http://www.meldrum.co.uk/mhp/videotex.html”><span style=”line-height: 150%”>Videotex software</span></a> has been used to produce exact representations of the original pages.</span><span style=”font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span> </span></p>
<p class=”MsoNormal”><b><span style=”font-family: ‘Verdana’,’sans-serif'”>THE BEGINNING OF THE END</span></b><b><span style=”font-size: 24pt”></span></b></p>
<p class=”MsoNormal”><b><span style=”font-size: 10pt; font-family: ‘Verdana’,’sans-serif'”><span>            </span>On </span></b><b><span style=”font-size: 10pt; font-family: ‘Arial’,’sans-serif'”>the BBC’s channels on the Astra digital platform the first sad and tangible signs of the beginning of the end for the BBC’s CEEFAX service</span></b><b><span style=”font-size: 10pt; font-family: ‘Verdana’,’sans-serif'”>.</span></b><span></span></p>
<p class=”MsoNormal” style=”text-align: justify; text-indent: 0.5in; line-height: 150%”><b><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Digital television services began in the UK in November 1998 and at that time it was expected that it would be accompanied, from December of that year, by a new high-definition digital text service. In the event that expectation proved wildly optimistic. Both the BBC and ITV were transmitting a pilot service the following year, but it was only on 1-Oct-1999 that the decoding software was made available on a trial basis, and even then only to those with Philips STBs. Subscribers with Pace and Nokia boxes had to wait until March 2000 before they were able to download a software update. Ironically, those with integrated digital televisions had to wait even longer.</span></b><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><b><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span><a href=”http://teletext.mb21.co.uk/gallery/digital/bbc-main.shtml”>BBC Text</a> </span></b><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>came first to ONdigital but it was not until March 2001 that it finally arrived at the Astra Digital platform. It is nicely designed but one obvious difference between it and CEEFAX is that the new service has <b>no page numbers</b> – navigation being by menu and cursor controls.</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>As first seen, <a href=”http://teletext.mb21.co.uk/gallery/digital/independent.shtml”><b>Digital Teletext</b></a> was a very sparse but seems to offer more in the way of high-definition pictures. Digital Teletext also provides a means of navigating by page numbers.In May 2000 Carlton Food and Carlton Cinema introduced Digital Teletext services but suddenly withdrew them two months later. Carlton announced that their two month trial was over, and the service was being withdrawn pending full launch later this year. This surprised everyone, as there was no indication that it was a trial service, and certainly ONdigital did not know, as they plugged it strongly in their magazine, including July’s edition. Carlton hyped up the launch of the service in May, announcing it as having the first interactive adverts. The Carlton Cinema service was <span>      </span>actually quite useful, including  programme listings, features about each film, a quiz and a featured actor feature.</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Meanwhile, in July 2000  the BBC temporarily augmented their Digital teletext service with a service devoted to the Wimbledon Tennis Championships.</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The new <a href=”http://teletext.mb21.co.uk/gallery/digital/skytext.shtml”><b>SkyText</b></a&gt; service is great, but all the terrestrial digital teletext services seem unacceptably slow to me. I wonder if the bandwidth will be made available so that they can be speeded up?</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>It’s hard to see how the BBC will refer to program backup information on BBC Text without page numbers to refer to and it will be most interesting to see both of these new channels develop into fully grown services. In the meantime your comments and observations on the new service would be welcome on <a href=”http://www.sneezes.freeserve.co.uk/teletext/list.html”><b>Teletext Chat</b></a>.</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The UK’s major cable operator, <b><a href=”http://teletext.mb21.co.uk/gallery/digital/ntl1.shtml”>ntl:</a></b&gt;, launched their DigitalPlus service in mid-2000 and was initially accompanied by a teletext service sourced from Teletext Ltd.</span></p>
<p class=”MsoNormal” style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>By the end of the year Teletext Ltd had rebranded their product and ntl had developed their <a href=”http://teletext.mb21.co.uk/gallery/digital/ntl2.shtml”>interactive service</a> to include content from other providers including InfoSpace, Weather Services International and the Manchester Evening News. This interactive service was rolled out to customers in their various franchise regions during 2001 with many customers having their set top boxes updated just in time for the Wimbledon tennis championships in June. At first the service was very buggy and attempts to use it would frequently cause the box to hang up, requiring disconnection from the mains to force a reboot but, to be fair, this situation rapidly improved.</span></p>

<h2><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Technology</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Teletext information is broadcast in the <a href=”http://en.wikipedia.org/wiki/Vertical_blanking_interval&#8221; title=”Vertical blanking interval”>vertical blanking interval</a> between image frames in a broadcast television signal. It is closely linked to the <a href=”http://en.wikipedia.org/wiki/PAL&#8221; title=”PAL”>PAL</a> broadcast system, and most PAL televisions include teletext <a href=”http://en.wikipedia.org/wiki/Decoder&#8221; title=”Decoder”>decoders</a>. Other teletext systems have been developed to work with the <a href=”http://en.wikipedia.org/wiki/SECAM&#8221; title=”SECAM”>SECAM</a> and <a href=”http://en.wikipedia.org/wiki/NTSC&#8221; title=”NTSC”>NTSC</a> systems, but teletext failed to gain widespread acceptance in North  America and other areas where NTSC is used. In contrast, teletext is nearly ubiquitous across <a href=”http://en.wikipedia.org/wiki/Europe&#8221; title=”Europe”>Europe</a> as well as some other regions, with most major broadcasters providing a teletext service. Common teletext services include TV schedules, regularly updated current affairs and sport news, simple games (such as quizzes) and subtitling for deaf people or in different languages.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span>Teletext uses a numbered page metaphor to present its information, all of which is broadcast in sequence; when a viewer keys in a page number, the receiver waits until that information is broadcast again, typically within a few seconds, and retrieves it for display on-screen. More sophisticated systems use a <a href=”http://en.wikipedia.org/wiki/Computer_memory&#8221; title=”Computer memory”>buffer memory</a> to store some or all of the teletext pages, for instantaneous display.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span>Because of its presentation of user-requested graphic information, Teletext can be seen as a predecessor of the <a href=”http://en.wikipedia.org/wiki/World_Wide_Web&#8221; title=”World Wide Web”>World Wide Web</a>. Unlike the <a href=”http://en.wikipedia.org/wiki/Internet&#8221; title=”Internet”>internet</a>, teletext is <a href=”http://en.wikipedia.org/wiki/Broadcasting_%28networks%29&#8243; title=”Broadcasting (networks)”>broadcast</a>, so it does not slow down further as the number of users increase. It has proved to be a reliable text news service during events such as the <a href=”http://en.wikipedia.org/wiki/September_11%2C_2001_terrorist_attacks&#8221; title=”September 11, 2001 terrorist attacks”>September 11, 2001 terrorist attacks</a>, during which the webpages of major news sites became inaccessible due to unexpected demand. Teletext is used for carrying special packets interpreted by TVs and video recorders, containing information about channels, programming, etc. (see “Other Teletext-related services”).</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span>Although the term “teletext” tends to be used to refer to the PAL-based system, or variants, the recent availability of <a href=”http://en.wikipedia.org/wiki/Digital_television&#8221; title=”Digital television”>digital television</a> has led to more advanced systems being provided that perform the same task, such as <a href=”http://en.wikipedia.org/wiki/MHEG-5&#8243; title=”MHEG-5″>MHEG-5</a> in the UK, and <a href=”http://en.wikipedia.org/wiki/Multimedia_Home_Platform&#8221; title=”Multimedia Home Platform”>Multimedia Home Platform</a>.</span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>In c.1970 the <a href=”http://en.wikipedia.org/wiki/BBC&#8221; title=”BBC”>BBC</a> had a brainstorming session in which it was decided to start researching ways to send <a href=”http://en.wikipedia.org/wiki/Closed_captioning&#8221; title=”Closed captioning”>closed captioning</a> information to audience. As the <b>Teledata</b> research continued they became increasingly interested in using the same system for delivering any sort of information, not just closed captioning. Displaying subtitles requires limited <a href=”http://en.wikipedia.org/wiki/Bandwidth&#8221; title=”Bandwidth”>bandwidth</a>, at a rate of perhaps a few words per second. However, by combining even a slow data rate with a suitable memory, pages of information could be sent and stored in the TV for later recall.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Meanwhile the <a href=”http://en.wikipedia.org/wiki/General_Post_Office&#8221; title=”General Post Office”>General Post Office</a> (whose telecommunications division later became <a href=”http://en.wikipedia.org/wiki/British_Telecom&#8221; title=”British Telecom”>British Telecom</a>) had been researching a similar concept since the late 1960s, known as <b><a href=”http://en.wikipedia.org/wiki/Viewdata&#8221; title=”Viewdata”>Viewdata</a></b>. Unlike Ceefax which was a one-way service carried in the existing TV signal, Viewdata was a two-way system using telephones. Since the Post Office owned the telephones, this was considered to be an excellent way to drive more customers to use the phones.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>In 1972 the BBC demonstrated their system, now known as <b><a href=”http://en.wikipedia.org/wiki/Ceefax&#8221; title=”Ceefax”>Ceefax</a></b> (“see facts”, the departmental stationery used the curious “Cx” logo), on various news shows. The <a href=”http://en.wikipedia.org/wiki/Independent_Television_Authority&#8221; title=”Independent Television Authority”>Independent Television Authority</a> (ITA) announced their own service in <a href=”http://en.wikipedia.org/wiki/1973&#8243; title=”1973″>1973</a>, known as <b><a href=”http://en.wikipedia.org/wiki/ORACLE_%28teletext%29&#8243; title=”ORACLE (teletext)”>ORACLE</a></b> (Optional Reception of Announcements by Coded Line Electronics).</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>In 1974 all the services agreed a standard for displaying the information. The display would be a simple 40×24 grid of text, with some <i>graphics characters</i> for constructing simple graphics. This standard was called <a href=”http://en.wikipedia.org/wiki/CEPT1&#8243; title=”CEPT1″>CEPT1</a>. The standard did not define the delivery system, so both Viewdata-like and Teledata-like services could at least share the TV-side hardware (which at that point in time was quite expensive). The standard also introduced a new term that covered all such services, teletext.<sup>[<i><a href=”http://en.wikipedia.org/wiki/Wikipedia:Citation_needed&#8221; title=”Citation needed”>citation needed</a></i>]</sup></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The “Broadcast Teletext Specification” was published in September 1976 jointly by the IBA, the BBC and the British Radio Equipment Manufacturers’ Association. Not to be outdone the GPO immediately announced a 1200/75 baud videotext service under the name <b><a href=”http://en.wikipedia.org/wiki/Prestel&#8221; title=”Prestel”>Prestel</a></b>.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Recent versions of the <a href=”http://en.wikipedia.org/wiki/CEPT1&#8243; title=”CEPT1″>CEPT1</a> standard are called <i>World System B</i> (also known as <b><a href=”http://en.wikipedia.org/wiki/World_System_Teletext&#8221; title=”World System Teletext”>WST</a></b>, or World System Teletext) and commonly known as European teletext.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>In 1980 a similar system called <a href=”http://en.wikipedia.org/wiki/Telidon&#8221; title=”Telidon”>Telidon</a> was developed in Canada. It used a simple graphics language that would allow a more complex circuit in the TV to decode not only characters, but simple graphics as well. To do this the graphic was encoded as a series of instructions (graphics primitives) like “polyline” which was represented as the characters PL followed by a string of digits for the X and Y values of the points on the line. This system was referred to as PDI (Picture Description Instructions). Later improved versions of Telidion were called <a href=”http://en.wikipedia.org/wiki/NAPLPS&#8221; title=”NAPLPS”>NAPLPS</a>.</span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>

<h2><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Introduction</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Following test transmissions in <a href=”http://en.wikipedia.org/wiki/1973&#8243; title=”1973″>1973</a>–<a href=”http://en.wikipedia.org/wiki/1974&#8243; title=”1974″>74</a>, towards the end of 1974 the BBC news department put together an editorial team of nine, including and led by Editor Colin McIntyre, to develop a news and information service. Initially limited to 30 pages, the Ceefax service was later expanded to 100 pages and was launched formally in 1976. It was followed quickly by ORACLE and <a href=”http://en.wikipedia.org/wiki/Prestel&#8221; title=”Prestel”>Prestel</a>. <a href=”http://en.wikipedia.org/wiki/Wireless_World&#8221; title=”Wireless World”>Wireless World</a> magazine ran a series of articles between November 1975 and June 1976 describing the design and construction of a Teletext decoder using mainly <a href=”http://en.wikipedia.org/wiki/Transistor-transistor_logic&#8221; title=”Transistor-transistor logic”>TTL</a> devices, however development was limited until the first TV sets with built-in decoders started appearing in <a href=”http://en.wikipedia.org/wiki/1977&#8243; title=”1977″>1977</a>. By <a href=”http://en.wikipedia.org/wiki/1982&#8243; title=”1982″>1982</a> there were two million such sets, and by the <a href=”http://en.wikipedia.org/wiki/1980s&#8221; title=”1980s”>mid-80s</a> they were available as an option for almost every European TV set, typically by means of a plug in circuit board. It took another decade before the decoders became a standard feature on almost all sets over 15″ (Teletext is still usually only an option for smaller “portable” sets). From the <a href=”http://en.wikipedia.org/wiki/1980s&#8221; title=”1980s”>mid-80s</a> both Ceefax and ORACLE were broadcasting several hundred pages on every channel, slowly changing them throughout the day.</span></p>

<h2><a title=”Function” name=”Function”></a><span class=”editsection”><span style=”font-size: 10pt; line-height: 150%”>]</span></span><span style=”font-size: 10pt; line-height: 150%”> <span class=”mw-headline”>Function</span></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>In the case of the Ceefax and Oracle systems and their successors in the UK, the teletext signal is transmitted as part of the ordinary analogue TV signal but concealed from view in the VBI (<a href=”http://en.wikipedia.org/wiki/Vertical_Blanking_Interval&#8221; title=”Vertical Blanking Interval”>Vertical Blanking Interval</a>) television lines which do not carry picture information. The teletext signal is digitally coded as 45-byte packets and can use lines 6–22 and 318–335. Some teletext services use a great number of lines, others, for reasons of bandwidth and technical issues, use less. The resulting data rate is 7000 <a href=”http://en.wikipedia.org/wiki/Bits_per_second&#8221; title=”Bits per second”>bit/s</a> per line. (40 usable 7-bit bytes per line, on each of 25 frames per second.)</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>A teletext page comprises one or more <i>frames</i>, each containing a screen-full of text. The pages are sent out one after the other in a continual loop. When the user requests a particular page the decoder simply waits for it to be sent, and then captures it for display. In order to keep the delays reasonably short, services typically only transmit a few hundred frames in total. Even with this limited number, waits can be up to 30 seconds, although Teletext broadcasters can control the speed and priority with which various pages are broadcast</span><span style=”font-size: 10pt; line-height: 150%”>.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Modern television sets, however, usually have a built-in memory, often for a few thousand different pages. This way, the teletext decoder captures every page sent out and stores it in memory, so when a page is requested by the user it can be loaded directly from memory instead of having to wait for the page to be transmitted. When the page is transmitted again, the television checks if the page in memory is still up-to-date and updates it if necessary.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The text can be displayed instead of the television image, or superimposed on it (a mode commonly called <i>mix</i>). Some pages, such as subtitles (<a href=”http://en.wikipedia.org/wiki/Closed_captioning&#8221; title=”Closed captioning”>closed captioning</a>) are <i>in-vision</i>, meaning that text is displayed in a block on the screen covering part of the television image.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The original standard provides a monospaced 40×24 character grid. The standard was improved in <a href=”http://en.wikipedia.org/wiki/1976&#8243; title=”1976″>1976</a> to allow for improved appearance and the ability to individually select the color of each character from a palette of 8. The proposed higher resolution Level 2 (<a href=”http://en.wikipedia.org/wiki/1981&#8243; title=”1981″>1981</a>) was not adopted in Britain (in-vision services from Ceefax &amp; ORACLE did use it at various times however, though even this was ceased by the BBC in 1996), although transmission rates were doubled from two to four lines a frame in <a href=”http://en.wikipedia.org/wiki/1981&#8243; title=”1981″>1981</a></span><span style=”font-size: 10pt; line-height: 150%”>.</span></p>

<h2><a title=”Other_systems” name=”Other_systems”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Other systems</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>A number of similar teletext services were developed in other countries, some of which attempted to address the limitations of the British-developed system, with its simple graphics and fixed page sizes.</span></p>

<h3><a title=”_Antiope” name=”_Antiope”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>France</span></span><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>: Antiope</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h3>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/wiki/Antiope_%28teletext%29&#8243; title=”Antiope (teletext)”>Antiope (teletext)</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>In France, where the <a href=”http://en.wikipedia.org/wiki/SECAM&#8221; title=”SECAM”>SECAM</a> standard is used in television broadcasting, a teletext system was developed in the late 1970s under the name <i>Antiope</i>. It had a higher data rate and was capable of dynamic page sizes, allowing more sophisticated graphics. It was phased out in favour of standard teletext in 1991.</span></p>

<h3><a title=”Telidon” name=”Telidon”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Canada</span></span><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>:Telidon</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h3>
<p class=”MsoNormal” style=”margin-left: 0.5in; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%”>Main article: <a href=”http://en.wikipedia.org/wiki/Telidon&#8221; title=”Telidon”>Telidon</a></span></i><span style=”font-size: 10pt; line-height: 150%”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The <a href=”http://en.wikipedia.org/wiki/Canadian_Broadcasting_Corporation&#8221; title=”Canadian Broadcasting Corporation”>CBC</a> ran a teletext service, IRIS, accessible only in <a href=”http://en.wikipedia.org/wiki/Calgary%2C_Alberta&#8221; title=”Calgary, Alberta”>Calgary</a>, <a href=”http://en.wikipedia.org/wiki/Toronto%2C_Ontario&#8221; title=”Toronto, Ontario”>Toronto</a> and <a href=”http://en.wikipedia.org/wiki/Montreal%2C_Quebec&#8221; title=”Montreal, Quebec”>Montreal</a>. It ran from <a href=”http://en.wikipedia.org/wiki/1983_in_Canada&#8221; title=”1983 in Canada”>1983</a> until about 1986, and used the Canadian-developed <a href=”http://en.wikipedia.org/wiki/Telidon&#8221; title=”Telidon”>Telidon</a> system, which was developed in 1980. Like Antiope, Telidon allowed significantly higher graphic resolution than standard tel</span><span style=”font-size: 10pt; line-height: 150%”>etext.</span></p>

<h3><a title=”United_States” name=”United_States”></a><span style=”font-size: 10pt; line-height: 150%”><span> </span><span class=”mw-headline”>United States</span></span></h3>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>A version of the European teletext standard designed to work with the <a href=”http://en.wikipedia.org/wiki/NTSC&#8221; title=”NTSC”>NTSC</a> television standard used in <a href=”http://en.wikipedia.org/wiki/North_America&#8221; title=”North America”>North America</a> was first demonstrated in the USA in 1978 by <a href=”http://en.wikipedia.org/wiki/United_States&#8221; title=”United States”>American</a> television network <a href=”http://en.wikipedia.org/wiki/CBS&#8221; title=”CBS”>CBS</a>, which decided to try both the British <a href=”http://en.wikipedia.org/wiki/Ceefax&#8221; title=”Ceefax”>Ceefax</a> and French <a href=”http://en.wikipedia.org/wiki/Antiope_%28teletext%29&#8243; title=”Antiope (teletext)”>Antiope</a> software for preliminary tryouts for a teletext service using station KMOX (now <a href=”http://en.wikipedia.org/wiki/KMOV&#8221; title=”KMOV”>KMOV</a>) in <a href=”http://en.wikipedia.org/wiki/St._Louis%2C_Missouri&#8221; title=”St. Louis, Missouri”>St. Louis, Missouri</a> as a testing ground. CBS decided on Antiope, and the service premiered on station <a href=”http://en.wikipedia.org/wiki/KNXT&#8221; title=”KNXT”>KNXT</a> (now <a href=”http://en.wikipedia.org/wiki/KCBS&#8221; title=”KCBS”>KCBS</a>) in <a href=”http://en.wikipedia.org/wiki/Los_Angeles&#8221; title=”Los Angeles”>Los Angeles</a>. Also in 1978, station <a href=”http://en.wikipedia.org/wiki/KSL-TV&#8221; title=”KSL-TV”>KSL</a> in <a href=”http://en.wikipedia.org/wiki/Salt_Lake_City%2C_Utah&#8221; title=”Salt Lake City, Utah”>Salt Lake City, Utah</a>, also premiered a teletext service using Ceefax.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Adoption in the United States was hampered due to a lack of a single teletext standard and consumer resistance to the high initial price of teletext decoders.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>A significant reason for the demise of American teletext was when Zenith introduced built-in <a href=”http://en.wikipedia.org/wiki/Closed_captioning&#8221; title=”Closed captioning”>closed captioning</a> decoders in TVs in the early 90s, as mandated by the <a href=”http://en.wikipedia.org/wiki/Federal_Communications_Commission&#8221; title=”Federal Communications Commission”>FCC</a>. It was not practical for Zenith to re-design their TV chassis models that previously had teletext decoder support to have both teletext and closed captioning support. So Zenith decided to drop the teletext features, therefore ending teletext service in the US in the early 1990s, considering Zenith was the only major manufacturer of teletext-equipped sets in America.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Nowadays, teletext or other similar technologies in the USA are practically non-existent, with the only technologies resembling such existing in the</span><span style=”font-size: 10pt; line-height: 150%”> country being <a href=”http://en.wikipedia.org/wiki/Closed_captioning&#8221; title=”Closed captioning”>closed captioning</a>, TV Guide On Screen, and <a href=”http://en.wikipedia.org/wiki/Extended_Data_Services&#8221; title=”Extended Data Services”>XDS</a> (eXtended Data Services).</span></p>

<h4><a title=”World_System_Teletext” name=”World_System_Teletext”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>World System Teletext</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h4>
<p class=”MsoNormal” style=”margin-left: 0.5in; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%”>Main article: <a href=”http://en.wikipedia.org/wiki/World_System_Teletext&#8221; title=”World System Teletext”>World System Teletext</a></span></i><span style=”font-size: 10pt; line-height: 150%”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>WST was also used for a short time in the USA, with services provided throughout the late 1970s and early 1980s by several regional American TV networks (such as the <a href=”http://en.wikipedia.org/wiki/University_of_Wisconsin-Madison&#8221; title=”University of Wisconsin-Madison”>University of Wisconsin-Madison</a>’s <i>Infotext</i> service in the mid-1980s, which was carried on several TV stations across <a href=”http://en.wikipedia.org/wiki/Wisconsin&#8221; title=”Wisconsin”>Wisconsin</a>, and Agtext, provided by <a href=”http://en.wikipedia.org/wiki/Kentucky_Educational_Television&#8221; title=”Kentucky Educational Television”>Kentucky Educational Television</a> and carried on KET’s stations, both services providing agriculturally oriented information) and major-market U.S. TV stations (such as <i>Metrotext</i>, which was formerly carried on station <a href=”http://en.wikipedia.org/wiki/KTTV&#8221; title=”KTTV”>KTTV</a> in <a href=”http://en.wikipedia.org/wiki/Los_Angeles&#8221; title=”Los Angeles”>Los Angeles</a>, and <i>KeyFax</i>, formerly on <a href=”http://en.wikipedia.org/wiki/WFLD&#8221; title=”WFLD”>WFLD</a> in <a href=”http://en.wikipedia.org/wiki/Chicago&#8221; title=”Chicago”>Chicago</a>).<a href=”http://en.wikipedia.org/wiki/Zenith_Electronics_Corporation&#8221; title=”Zenith Electronics Corporation”>Zenith</a> manufactured models of television sets in the USA in the 1980s, most notably their <i>Digital System 3</i> line, that had built-in WST teletext decoders as a feature, much like most British/European TV sets. Teletext services in the USA like <a href=”http://en.wikipedia.org/wiki/Electra_%28teletext%29&#8243; title=”Electra (teletext)”>Electra</a> could be received with one of these sets, but these were mostly more expensive higher-end sets offered by Zenith, possibly causing Electra (and American teletext in general) to never catch on with the public.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span>Australian company <a href=”http://en.wikipedia.org/wiki/Dick_Smith_Electronics&#8221; title=”Dick Smith Electronics”>Dick Smith Electronics</a> (DSE) also offered through their USA distributors a set-top WST teletext decoder kit. The kit used as its core the same teletext <a href=”http://en.wikipedia.org/wiki/Decoding&#8221; title=”Decoding”>decoding</a> module (manufactured by UK electronics company <a href=”http://en.wikipedia.org/wiki/Mullard&#8221; title=”Mullard”>Mullard</a>) installed in most British TV sets, with additional circuitry to adapt it for American <a href=”http://en.wikipedia.org/wiki/NTSC&#8221; title=”NTSC”>NTSC</a> video, and to utilize it in a separate set-top box.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span>The successor of WST in Europe and other countries is based on the Enhanced Teletext Specification from <a href=”https://kelompokkami.wordpress.com/wp-admin/pt%20kom/sd.htm#External_links#External_links”>ETSI</a&gt;. ETSI EN300706 classifies Teletext in Level 1.5, Level 2.5 and Level 3.5. Level 1.5 covers all European languages plus Arabic and Hebrew. <a href=”https://kelompokkami.wordpress.com/wp-admin/pt%20kom/sd.htm#Level_2.5_teletext#Level_2.5_teletext”>Level 2.5</a> provides display enhancements. Level 3.5 adds proportional fonts and high resolution graphics. Level 1.5 is the most popular Teletext standard in analogue and DVB transmissions in Europe. Sometimes it is called ‘classical’ Teletext. Level 3.5 was outperformed through the success of html and other modern standards.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”>Teletext differs in navigation methods provided by the broadcaster like FLOF (link information for a tree of pages) or TOP (Table of Pages).</span></p>

<h4><a title=”NABTS” name=”NABTS”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>NABTS</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h4>
<p class=”MsoNormal” style=”margin-left: 0.5in; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%”>Main article: <a href=”http://en.wikipedia.org/wiki/NABTS&#8221; title=”NABTS”>NABTS</a></span></i><span style=”font-size: 10pt; line-height: 150%”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Later, an official North American standard of teletext, called <b><a href=”http://en.wikipedia.org/wiki/NABTS&#8221; title=”NABTS”>NABTS</a></b> (North American Broadcast Teletext Specification) was developed in the early 1980s by <a href=”http://en.wikipedia.org/wiki/Norpak&#8221; title=”Norpak”>Norpak</a>, a Canadian company. NABTS provided improved graphic and text capability over WST, but was quite short-lived. This was mainly due to the expensive cost of NABTS decoders, costing in the thousands of dollars upon their release to the public. NABTS, however, was adopted for a short while by American TV networks <a href=”http://en.wikipedia.org/wiki/NBC&#8221; title=”NBC”>NBC</a> &amp; <a href=”http://en.wikipedia.org/wiki/CBS&#8221; title=”CBS”>CBS</a> throughout the early-to-mid 80s, CBS using it for their short-lived <b><a href=”http://en.wikipedia.org/wiki/ExtraVision&#8221; title=”ExtraVision”>ExtraVision</a></b> teletext service, which premiered after the early Antiope &amp; Ceefax trials by CBS, KNXT, and NBC, who had a NABTS-based service called <a href=”http://en.wikipedia.org/w/index.php?title=NBC_Teletext&amp;action=edit&#8221; title=”NBC Teletext”>NBC Teletext</a> for a very short time in the mid-1980s. NBC discontinued their service in 1986 due to the cost of NABTS decoders not dropping to an affordable level for the consumer public.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The NABTS protocol received a revival of sorts in the late 90s, when it was used for the <a href=”http://en.wikipedia.org/wiki/Datacasting&#8221; title=”Datacasting”>datacasting</a> features of <a href=”http://en.wikipedia.org/wiki/WebTV_for_Windows&#8221; title=”WebTV for Windows”>WebTV for Windows</a> under <a href=”http://en.wikipedia.org/wiki/Windows_98&#8243; title=”Windows 98″>Windows 98</a>, and for <a href=”http://en.wikipedia.org/wiki/Intel&#8221; title=”Intel”>Intel</a>’s now-defunct <b><a href=”http://en.wikipedia.org/wiki/InterCast&#8221; title=”InterCast”>InterCast</a></b> service (also for Windows as well), using a proper <a href=”http://en.wikipedia.org/wiki/TV_tuner_card&#8221; title=”TV tuner card”>TV tuner card</a> (such as the <a href=”http://en.wikipedia.org/wiki/ATI_Technologies&#8221; title=”ATI Technologies”>ATI</a> All-In-Wonder or <a href=”http://en.wikipedia.org/wiki/Hauppauge_Computer_Works&#8221; title=”Hauppauge Computer Works”>Hauppauge</a>’s Win-TV).</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>InterCast was a modern teletext-like system created by <a href=”http://en.wikipedia.org/wiki/Intel&#8221; title=”Intel”>Intel</a> in <a href=”http://en.wikipedia.org/wiki/1996&#8243; title=”1996″>1996</a>, using a TV tuner card installed in a desktop <a href=”http://en.wikipedia.org/wiki/Personal_computer&#8221; title=”Personal computer”>PC</a> running Windows with the InterCast Viewer software. The software would receive data representing <a href=”http://en.wikipedia.org/wiki/HTML&#8221; title=”HTML”>HTML</a> pages via the <a href=”http://en.wikipedia.org/wiki/VBI&#8221; title=”VBI”>VBI</a> (Vertical Blanking Interval) of a television channel’s video, while displaying in a window in the InterCast software the TV channel itself. The <a href=”http://en.wikipedia.org/wiki/HTML&#8221; title=”HTML”>HTML</a> data received would then be displayed in another window in the Intercast software. It usually was extra supplemental information relevant to the TV program being viewed, such as extra clues for the viewer during a murder mystery show, or extra news headlines or extended weather forecasts during a newscast.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><a href=”http://en.wikipedia.org/wiki/NBC&#8221; title=”NBC”>NBC</a>, as well as <a href=”http://en.wikipedia.org/wiki/The_Weather_Channel_%28United_States%29&#8243; title=”The Weather Channel (United States)”>The Weather Channel</a>, <a href=”http://en.wikipedia.org/wiki/CNN&#8221; title=”CNN”>CNN</a> and <a href=”http://en.wikipedia.org/wiki/MTV2&#8243; title=”MTV2″>M2</a> (now MTV2), utilized InterCast technology to complement their programming. InterCast, however, fell into disuse, and Intel discontinued support of InterCast a few years later.</span></p>

<h4><a title=”Electra” name=”Electra”></a><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span> </span><span class=”mw-headline”>Electra</span></span></h4>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/wiki/Electra_%28teletext%29&#8243; title=”Electra (teletext)”>Electra (teletext)</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Perhaps the most prominent of American teletext providers was the <i><a href=”http://en.wikipedia.org/wiki/Electra_%28teletext%29&#8243; title=”Electra (teletext)”>Electra</a></i> teletext service, which was broadcast starting in the early 1980s on the vertical blanking interval (<a href=”http://en.wikipedia.org/wiki/VBI&#8221; title=”VBI”>VBI</a>) of the American cable channel <a href=”http://en.wikipedia.org/wiki/TBS_Superstation&#8221; title=”TBS Superstation”>WTBS</a>. Electra was owned and operated by <a href=”http://en.wikipedia.org/wiki/Taft_Broadcasting&#8221; title=”Taft Broadcasting”>Taft Broadcasting</a> and <a href=”http://en.wikipedia.org/wiki/Satellite_Syndicated_Systems&#8221; title=”Satellite Syndicated Systems”>Satellite Syndicated Systems</a> (SSS). Electra ran up until 1993, when it was shut down due to <a href=”http://en.wikipedia.org/wiki/Zenith&#8221; title=”Zenith”>Zenith</a>, the prominent (and only) American TV manufacturer at the time offering teletext features in their sets decided to discontinue such features, as well as a lack of funding and lagging interest in teletext by the American consumer.</span></p>

<h4><a title=”WaveTop” name=”WaveTop”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>WaveTop</span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></h4>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/w/index.php?title=WaveTop&amp;action=edit&#8221; title=”WaveTop”>WaveTop</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Another service in the USA similar in delivery and content to teletext was the <i>WaveTop</i> service, provided and operated by the <a href=”http://en.wikipedia.org/w/index.php?title=Wavephore&amp;action=edit&#8221; title=”Wavephore”>Wavephore</a> Corporation. It used the same types of InterCast-compatible TV tuner cards, and used an application that ran under Windows, like InterCast. In fact, WaveTop software was also bundled with TV tuner cards that had InterCast software bundled with them as well.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>However, Wavetop was an independent service from InterCast, and wasn’t a complementary service to a television program or channel like the latter In fact, viewing television with a TV card was not possible while the WaveTop software was running, since the software utilized the TV tuner card as a full-time data receiver.WaveTop provided content from several different providers in the form of HTML pages displayed in the WaveTop software, such as news articles from the <a href=”http://en.wikipedia.org/wiki/New_York_Times&#8221; title=”New York Times”>New York Times</a>, weather information provided by <a href=”http://en.wikipedia.org/wiki/The_Weather_Channel_%28United_States%29&#8243; title=”The Weather Channel (United States)”>The Weather Channel</a>, and sports from <a href=”http://en.wikipedia.org/wiki/ESPN&#8221; title=”ESPN”>ESPN</a>. It also delivered short video clips, usually commercials, that could be viewed in the software as well.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>When it was in operation, WaveTop’s data was delivered on the <a href=”http://en.wikipedia.org/wiki/VBI&#8221; title=”VBI”>VBI</a> of local public TV stations affiliated with the <a href=”http://en.wikipedia.org/wiki/PBS&#8221; title=”PBS”>PBS</a> network through their <a href=”http://en.wikipedia.org/wiki/PBS_National_Datacast&#8221; title=”PBS National Datacast”>PBS National Datacast</a> <a href=”http://www.pbsnationaldatacast.com/&#8221; title=”http://www.pbsnationaldatacast.com”>%5B1%5D</a&gt; division, that the TV card &amp; WaveTop software tuned into to receive the service.</span></p>

<h4><a title=”Guide.2B” name=”Guide.2B”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Guide</span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></h4>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/wiki/Guide_Plus&#8221; title=”Guide Plus”>Guide Plus</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Yet another service in the U.S. that relied on data delivery via the <a href=”http://en.wikipedia.org/wiki/VBI&#8221; title=”VBI”>VBI</a> like teletext, was the <i>Guide+</i> (<i>Guide Plus</i>, also referred to as <i>GuidePlus+</i> as well) service provided and developed by <a href=”http://en.wikipedia.org/wiki/Gemstar&#8221; title=”Gemstar”>Gemstar</a>. There were several models of television sets made throughout the 90s by <a href=”http://en.wikipedia.org/wiki/Thomson_SA&#8221; title=”Thomson SA”>Thomson Consumer Electronics</a> under the <a href=”http://en.wikipedia.org/wiki/RCA&#8221; title=”RCA”>RCA</a> and <a href=”http://en.wikipedia.org/wiki/General_Electric&#8221; title=”General Electric”>General Electric</a> brands that had built-in Guide+ decoders. Guide+ was an on-screen interactive program guide that provided current TV schedule listings, as well as other information like news headlines. Some Guide+ equipped sets from RCA even had an <a href=”http://en.wikipedia.org/wiki/IR&#8221; title=”IR”>IR</a>-emitting sensor that could be plugged in to the back of the TV, to control a VCR to record programs which could be selected from the on-screen Guide+ listings. In some ways, this was very similar to the <a href=”http://en.wikipedia.org/w/index.php?title=Video_Programming_by_Teletext&amp;action=edit&#8221; title=”Video Programming by Teletext”>Video Programming by Teletext (VPT)</a>, <a href=”http://en.wikipedia.org/wiki/Video_Program_System&#8221; title=”Video Program System”>Video Program System</a> (VPS), and <a href=”http://en.wikipedia.org/wiki/Programme_Delivery_Control&#8221; title=”Programme Delivery Control”>Programme Delivery Control</a> (PDC) features of British/European teletext.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Guide+ was a free service, supported by advertisements displayed on-screen in the Guide+ menu and listing screens, not unlike <a href=”http://en.wikipedia.org/wiki/Banner_ads&#8221; title=”Banner ads”>banner ads</a> displayed on web pages. Guide+ was delivered over the <a href=”http://en.wikipedia.org/wiki/VBI&#8221; title=”VBI”>VBI</a> of select local American TV stations.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Guide+ was discontinued by Gemstar in June 2004, and soon afterwards, <a href=”http://en.wikipedia.org/wiki/Thomson_SA&#8221; title=”Thomson SA”>Thomson</a> dropped the Guide+ features from all RCA and GE television sets made afterward.However, Guide+ in America has now been replaced by Gemstar with a similar service (delivered in the same fashion via VBI like Guide+), called <i><a href=”http://en.wikipedia.org/wiki/TV_Guide_On_Screen&#8221; title=”TV Guide On Screen”>TV Guide On Screen</a></i> <a href=”http://www.gemstartvguide.com/whatwedo/tvgonscreen.asp&#8221; title=”http://www.gemstartvguide.com/whatwedo/tvgonscreen.asp”>%5B2%5D</a&gt;. A small amount of televisions, <a href=”http://en.wikipedia.org/wiki/DVD_recorder&#8221; title=”DVD recorder”>DVD recorders</a>, and <a href=”http://en.wikipedia.org/wiki/Digital_video_recorder&#8221; title=”Digital video recorder”>digital video recorders</a> are now being released with <i>TV Guide On Screen</i> capabilities. The Guide+ name &amp; service is still used in Europe by Gemstar. (The same service is known in Japan as G-Guide).</span></p>

<h4><a title=”Star_Sight” name=”Star_Sight”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Star Sight</span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></h4>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/w/index.php?title=Star_Sight&amp;action=edit&#8221; title=”Star Sight”>Star Sight</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Similar to Guide+ was <i>Star Sight</i> <a href=”http://www.starsight.com/&#8221; title=”http://www.starsight.com”>%5B3%5D</a&gt;, with its decoders built in to TVs manufactured by Zenith, Samsung, Sony, Toshiba, Magnavox, and others. This was an electronic program guide service similar to Guide+, but was a service that relied on monthly subscription fees paid by the user, not from revenue gathered from on-screen advertisements like Guide+. Star Sight discontinued operations on July 21, <a href=”http://en.wikipedia.org/wiki/2003&#8243; title=”2003″>2003</a>, due to a lack of subscribers to the service. Star Sight’s data was also delivered on the <a href=”http://en.wikipedia.org/wiki/VBI&#8221; title=”VBI”>VBI</a> of local PBS stations through the PBS National Datacast division, much like how WaveTop was delivered as mentioned previously in this article.</span></p>

<h2><a title=”Later_developments” name=”Later_developments”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Later developments</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>While the basic teletext format has remained unchanged in more than 30 years, a number of improvements and additions have been made.</span></p>

<ul type=”disc”>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><a href=”http://en.wikipedia.org/wiki/Standardization&#8221; title=”Standardization”>Standard</a>      <a href=”http://en.wikipedia.org/wiki/Electronic_program_guide&#8221; title=”Electronic program guide”>Electronic Programme Guides</a>, like <a href=”http://en.wikipedia.org/wiki/NexTView&#8221; title=”NexTView”>NexTView</a>,      are based on teletext, using a compact <a href=”http://en.wikipedia.org/wiki/Binary_file&#8221; title=”Binary file”>binary</a>      format instead of preformatted text pages. </span></li>
</ul>
<ul type=”disc”>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Various other kinds      of information are sent over the Teletext protocol. For instance, <a href=”http://en.wikipedia.org/wiki/Programme_Delivery_Control&#8221; title=”Programme Delivery Control”>Programme Delivery Control</a>      signals—used by video recorders for starting/stopping recording at the      correct time even during changes in programming—are sent as teletext      packets. A similar, but different, standard <a href=”http://en.wikipedia.org/wiki/Video_Programming_System&#8221; title=”Video Programming System”>Video Programming System</a> is also used      for this purpose. </span></li>
</ul>
<ul type=”disc”>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Teletext pages may      contain special packages allowing VCR’s to interpret their contents. This      is used in relation to the <a href=”http://en.wikipedia.org/w/index.php?title=Video_Programming_by_Teletext&amp;action=edit&#8221; title=”Video Programming by Teletext”>Video Programming by Teletext</a>      (also known as <b>startext</b>) system which allows users to program their      videos for recording by simply selecting the program on a teletext page with      a listing of programs. </span></li>
</ul>
<ul type=”disc”>
<li class=”MsoNormal”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Other standards      define how special teletext packets may contain information about the name      of the channel and the program currently being shown. </span></li>
</ul>
<h3><a title=”Video_Program_System” name=”Video_Program_System”></a><span style=”font-size: 10pt; line-height: 150%”><span> </span><span class=”mw-headline”>Video Program System</span></span></h3>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/wiki/Video_Program_System&#8221; title=”Video Program System”>Video Program System</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>A closely related service is the <i>Video Program System</i> (VPS), introduced in Germany in 1985. Like teletext, this signal is also broadcast in the vertical blanking interval. It consists only of 32 bits of data, primarily the date and time for which the broadcast of the currently running TV programme was originally scheduled. Video recorders can use this information (instead of a simple timer) in order to automatically record a scheduled programme, even if the broadcast time changes after the user programmes the VCR. VPS also provides a PAUSE code; broadcasters can use it to mark interruptions and pause the recorders, however advertisement-financed broadcasters tend not to use it during their ad breaks. VPS (line 16) definition is now included in the <a href=”http://en.wikipedia.org/wiki/PDC&#8221; title=”PDC”>PDC</a> standard from <a href=”http://en.wikipedia.org/wiki/ETSI&#8221; title=”ETSI”>ETSI</a>.</span></p>

<h3><a title=”Prestel” name=”Prestel”></a><span style=”font-size: 10pt; line-height: 150%”><span> </span><span class=”mw-headline”>Prestel</span></span></h3>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/wiki/Prestel&#8221; title=”Prestel”>Prestel</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span><a href=”http://en.wikipedia.org/wiki/Prestel&#8221; title=”Prestel”>Prestel</a> was a British information-retrieval system based on Teletext protocols. However, it was essentially a different system, using a modem and the phone system to transmit and receive the data, comparable to systems such as France’s <a href=”http://en.wikipedia.org/wiki/Minitel&#8221; title=”Minitel”>Minitel</a>. The modem was asymmetric, with data sent at 75 bit/s, and received 1200 bit/s. This two-way nature allowed pages to be served on request, in contrast to the TV-based systems’ sequential rolling method. It also meant that a limited number of extra services were available such as booking event or train tickets and a limited amount of online banking.</span></p>

<h3><a title=”Interactive_teletext” name=”Interactive_teletext”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Interactive teletext</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h3>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>Some TV channels offer a service called <b>interactive teletext</b> to remedy some of the shortcomings of standard teletext. To use interactive teletext, the user calls a special <a href=”http://en.wikipedia.org/wiki/Telephone&#8221; title=”Telephone”>telephone</a> number with a regular telephone. A computer then instructs the user to go to a certain teletext page which has been assigned to the customer for that session. Usually the page initially contains a menu with options and the user chooses among the options using the buttons on the telephone. When a choice has been made, the selected page is immediately broadcast and can be viewed by the user. This is in contrast with usual teletext where the customer has to wait for the selected page to be broadcast, because the pages are broadcast sequentially. This technology enables teletext to be used for games, <a href=”http://en.wikipedia.org/wiki/Chat&#8221; title=”Chat”>chat</a>, access to databases etc. It allows one to overcome the limitations on the number of available pages. On the other hand, only a limited number of users can use the service at the same time, since one page is allocated per user. Some channels solve this by taking into account where the user is geographically calling from and by broadcasting different teletext pages in different geographical regions. In that way, two different users can be assigned the same page number at the same time as long as they don’t receive the TV signals from the same source. Another drawback to the technology is the privacy concerns in that many users can see what a user is doing because the interactive pages are received by all viewers. Also, the user usually has to pay for the telephone call to the TV station. For these reasons, these services have largely been superseded by the <a href=”http://en.wikipedia.org/wiki/World_Wide_Web&#8221; title=”World Wide Web”>World Wide Web</a>.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>

<h2><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Level 2.5 teletext</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p class=”MsoNormal” style=”margin-left: 0.5in; text-align: justify; line-height: 150%”><i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Main article: <a href=”http://en.wikipedia.org/wiki/HiText&#8221; title=”HiText”>HiText</a></span></i><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”></span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><a href=”http://en.wikipedia.org/wiki/Image:Teletext_level1_0_lebel2_5.jpg&#8221; title=”Comparison between Teletext Level 1.0 and Teletext Level 2.5.”><span style=”color: blue; text-decoration: none”><!–[if gte vml 1]&amp;gt;                                                  &amp;lt;![endif]–><!–[if !vml]–><img src=”/Users/Hp/AppData/Local/Temp/msohtmlclip1/01/clip_image001.jpg” alt=”Comparison between Teletext Level 1.0 and Teletext Level 2.5.” border=”0″ height=”200″ width=”500″ /><!–[endif]–></span></a></span></p>
<p class=”MsoNormal” style=”text-align: center; line-height: 150%” align=”center”><i><span style=”font-size: 8pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><a href=”http://en.wikipedia.org/wiki/Image:Teletext_level1_0_lebel2_5.jpg&#8221; title=”Enlarge”><span style=”color: blue; text-decoration: none”><!–[if gte vml 1]&amp;gt;   &amp;lt;![endif]–><!–[if !vml]–><img src=”/Users/Hp/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif” border=”0″ height=”11″ width=”15″ /><!–[endif]–></span></a>Comparison between Teletext Level 1.0 and Teletext Level 2.5.</span></i></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>A new graphic standard found its way to the European market around <a href=”http://en.wikipedia.org/wiki/2000&#8243; title=”2000″>2000</a>: Level 2.5 or <i>HiText</i>. With Level 2.5 it is possible to set a background colour and have higher resolution text and images. However, very few television stations transmit their teletext in this new standard. One of the problems with Level 2.5 is that it often takes several transmission cycles before the higher resolution items show on the screen. In order to watch Level 2.5 teletext, a rather recent television set with a special decoder chip is required.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>However, the system has not been widely implemented, with only a handful of European state broadcasters supporting it. Television stations which are known to transmit teletext in Level 2.5 include the <a href=”http://en.wikipedia.org/wiki/Netherlands&#8221; title=”Netherlands”>Dutch</a> public broadcaster <a href=”http://en.wikipedia.org/wiki/Nederlandse_Omroep_Stichting&#8221; title=”Nederlandse Omroep Stichting”>NOS</a> (background colour on all pages, and a test page with hi-res graphics) and the German <a href=”http://en.wikipedia.org/wiki/ZDF&#8221; title=”ZDF”>ZDF</a> and <a href=”http://en.wikipedia.org/wiki/Bayerischer_Rundfunk#Television_channels&#8221; title=”Bayerischer Rundfunk”>Bayerisches Fernsehen</a> (completely backwards-compatible Level 2.5 teletext, with higher quality text and graphics on nearly all pages), as well as <a href=”http://en.wikipedia.org/wiki/Arte&#8221; title=”Arte”>Arte</a> and <a href=”http://en.wikipedia.org/wiki/3sat&#8221; title=”3sat”>3sat</a> on some pages.</span></p>
<p style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”> </span></p>

<h2><a title=”Levels” name=”Levels”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Levels</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”>These are taken from <a href=”http://exampointers.com/teletext/teletext.phtml&#8221; title=”http://exampointers.com/teletext/teletext.phtml”>http://exampointers.com/teletext/teletext.phtml</a></span></p&gt;

<table class=”MsoNormalTable” border=”0″ cellpadding=”0″>
<tr>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”text-align: center; line-height: 150%” align=”center”><b><span style=”font-size: 10pt; line-height: 150%”>Level</span></b></p>
</td>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”text-align: center; line-height: 150%” align=”center”><b><span style=”font-size: 10pt; line-height: 150%”>Description</span></b></p>
</td>
</tr>
<tr>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”>1</span></p>
</td>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>The initial specifications   set out by the BBC, IBA, BREMA in September 1976.</span></p>
</td>
</tr>
<tr>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”>2</span></p>
</td>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Multi-language text, wider   range of display attributes that may be non-spacing, wider range of colours   and an extended mosaic pictorial set.</span></p>
</td>
</tr>
<tr>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”>3</span></p>
</td>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Dynamically Redefined   Character Set (DRCS) allowing the display of non-Roman characters (e.g.   Arabic and Chinese). Pictorial Graphic characters can also be defined.</span></p>
</td>
</tr>
<tr>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”>4</span></p>
</td>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Full geometric graphics.   It needs computing power to generate the display from a sequence of drawing   instructions. The colour palette has 250,000 shades.</span></p>
</td>
</tr>
<tr>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”>5</span></p>
</td>
<td style=”padding: 0.75pt”>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Full-definition still   pictures allows better quality than video cameras. Modulated onto a carrier.   No noise added to the picture during transmission.</span></p>
</td>
</tr>
</table>
<p style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”> </span></p>

<h2><a title=”Digital_teletext” name=”Digital_teletext”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Digital teletext</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Digital television introduced “digital teletext” which, despite the previous teletext standard’s digital nature, has entirely different standards, such as <a href=”http://en.wikipedia.org/wiki/MHEG-5&#8243; title=”MHEG-5″>MHEG-5</a> and <a href=”http://en.wikipedia.org/wiki/Multimedia_Home_Platform&#8221; title=”Multimedia Home Platform”>Multimedia Home Platform</a>. However, standard teletext remains very popular. Some digital television platforms such as <a href=”http://en.wikipedia.org/wiki/Sky_Digital_%28UK%29&#8243; title=”Sky Digital (UK)”>Sky Digital</a> in the UK and Ireland incorporate separate teletext streams (used by the BBC from 1998 to 2004, and still used by <a href=”http://en.wikipedia.org/wiki/Republic_of_Ireland&#8221; title=”Republic of Ireland”>Irish</a> broadcaster <a href=”http://en.wikipedia.org/wiki/RT%C3%89&#8243; title=”RTÉ”>RTÉ</a>), which are provided to the television set in the normal analogue TV manner. Such emulation of analogue teletext on digital TV platforms may ensure its continued use for some time (particularly as there are no plans for an immediate transition to digital terrestrial transmission in some countries, such as Ireland). This emulation is only possible due to the <a href=”http://en.wikipedia.org/wiki/DVB-TXT&#8221; title=”DVB-TXT”>DVB-TXT</a> and <a href=”http://en.wikipedia.org/wiki/DVB-VBI&#8221; title=”DVB-VBI”>DVB-VBI</a> sub-standards of <a href=”http://en.wikipedia.org/wiki/DVB&#8221; title=”DVB”>DVB</a>, which allow a set-top box or integrated DVB TV to emulate the vertical blanking interval data in which teletext is carried.</span></p>

<h2><a title=”Other_Teletext-related_services” name=”Other_Teletext-related_services”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Other Teletext-related services</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Various other kinds of information are sent over the Teletext protocol. For instance, <a href=”http://en.wikipedia.org/wiki/Programme_Delivery_Control&#8221; title=”Programme Delivery Control”>Programme Delivery Control</a> signals—used by video recorders for starting/stopping recording at the correct time even during changes in programming—are sent as teletext packets. A similar, but different, standard <a href=”http://en.wikipedia.org/wiki/Video_Programming_System&#8221; title=”Video Programming System”>Video Programming System</a> is also used for this purpose.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>Teletext pages may contain special packages allowing VCR’s to interpret their contents. This is used in relation to the <a href=”http://en.wikipedia.org/w/index.php?title=Video_Programming_by_Teletext&amp;action=edit&#8221; title=”Video Programming by Teletext”>Video Programming by Teletext</a> (also known as <b>startext</b>) system which allows users to program their videos for recording by simply selecting the program on a teletext page with a listing of programs.Other standards define how special teletext packets may contain information about the name of the channel and the program currently being shown.</span></p>

<h2><a title=”Cessation_of_service” name=”Cessation_of_service”></a><span class=”mw-headline”><span style=”font-size: 10pt; line-height: 150%”>Cessation of service</span></span><span style=”font-size: 10pt; line-height: 150%”></span></h2>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%”><span>                </span></span><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”>A number of broadcast authorities have recently found fit to cease the transmission of teletext services, notably <a href=”http://en.wikipedia.org/wiki/CNN_International&#8221; title=”CNN International”>CNN International</a> <a href=”http://edition.cnn.com/cnntext/&#8221; title=”http://edition.cnn.com/cnntext/”>%5B4%5D</a&gt;. Most pages are still available, although they have not been updated since <a href=”http://en.wikipedia.org/wiki/October_31&#8243; title=”October 31″>31 October</a> <a href=”http://en.wikipedia.org/wiki/2006&#8243; title=”2006″>2006</a>.</span></p>
<p style=”text-align: justify; line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”><span>            </span>The BBC has also announced that Ceefax is to be phased out in the run-up to the UK Digital Switchover in 2012. The full service is no longer carried on any digital services, although many channels on Sky still broadcast teletext subtitles and may still have a small number of active pages <a href=”http://teletext.mb21.co.uk/gallery/ceefax/end.shtml&#8221; title=”http://teletext.mb21.co.uk/gallery/ceefax/end.shtml”>%5B5%5D</a&gt;. Teletext will end in each region after analogue broadcasts finish.</span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>
<p class=”MsoNormal” style=”line-height: 150%”><span style=”font-size: 10pt; line-height: 150%; font-family: ‘Arial’,’sans-serif'”> </span></p>

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s