Chapter 2
Digital Satellite, Terrestrial and Cable Broadcasting Technologies - the State of the Art

It is possible to divide digital broadcasting technology into three types according to how it is utilised:

They are all delivered in the same way as digital data as distinct from an analogue signal. They can also be broadcast via satellite, cable and terrestrial means. However, the method of receiving this signal will vary.

2.1 Data Broadcasting

Generally, data broadcasting involves the delivery of multimedia content directly to a computer. This involves installing a specific data card into the computer for receiving the data and converting it into a format that can be utilised by the computer. As most commercial data broadcasting services deliver via satellite this data card will need to be connected to a satellite dish. Requests for specific data are via the "return path", currently involving a modem connected to a computer generally via a normal telephone line. However, a new generation of two-way satellite links using 90-cm dishes is planned to be available towards the end of 1999. It will also be possible for higher-speed return channel links to be available via cable modems if connected to cable networks.

Various European satellite operators including Astra, Eutelsat and Hispasat have implemented satellite data broadcasting networks (DBNs). The wide area coverage of a single satellite footprint and the possible bit rates of more than 30 Mbit/sec per transponder could enable a typical CD-ROM to be transmitted to a whole continent in under three minutes. With more than 16 million PCs bought in Europe in 1996, and more than 30 million households having direct access to satellite transmissions, the potential for utilising this technology is huge. A number of commercial services are now available across Europe. However, they have tended not to focus towards the home market at present. This report does include a number of examples of educational use to schools (See Chapter 4)

2.2 Digital Radio

There are a number of broadcasters broadcasting in a digital radio format in various countries of Europe including the UK and Germany. However, currently the main obstacle to this development is the high cost of radio receivers (about 700 euro). It is also possible to plug in a data card into a computer to receive digital radio. Digital radio not only offers high quality sound particularly when on the move but it can also offer some limited multimedia.

This study did investigate the potential for utilising digital radio for education and training purposes but it was difficult to see any unique opportunities which were not already becoming available via digital TV or via the Internet. The multimedia component of digital radio is very limited due to the limited bandwidth. Better multimedia content is already accessible via the Internet. There is the potential for broadcasting learning resources in the form of data to a local community via a local radio station, but this could be done without digital radio. Digital radio is in fact just the broadcasting of data.

The transmission of data through local terrestrial transmitters in a similar way that local radio is broadcast does offer some interesting opportunities for education and training and should be investigated further once digital radio starts to take off. Predictions are that this will not be until 2003 when digital radio receivers start to be installed in cars, thus bringing down the cost of the receivers and encouraging more listeners. In turn this will encourage more radio stations to broadcast in a digital format and will enable a better assessment of what bandwidth could be utilised for localised terrestrial data broadcasting.

Due to its limited opportunities for education and training the study did not investigate digital radio any further. However, it is noted that many radio stations also broadcast using streaming audio via the web and this is increasing world-wide access to many local radio stations previously unheard of outside their local areas. Low cost access to learning programmes via the web does offer a lot of potential.

2.3 Digital TV

Digital TV is seen as offering the biggest potential for education and training purposes as most European households already have a television and digital TV broadcasting is already widespread across Europe particularly via satellite. It is also starting to be broadcast via cable and also via terrestrial means. However, the latest figures available indicate that only about 2.2% (3) of EU TV households were accessing digital TV services in mid 1998.

Set-top Box

For all delivery mechanisms a digital set-top box has to be connected between a normal TV and the incoming signal. The set-top box serves a number of purposes:

According to a Datamonitor report (4), the installed base of digital set-top boxes in Europe will grow rapidly from 1997 to 2003, enabling consumers to receive interactive services via their television sets, not just their PCs. The report predicts that in 2003 there will be 29 million digital set-top boxes in Europe enabled with a modem for interactive services. Modems are fast becoming standard in digital set-top boxes in Europe, already extending the reach of interactive services beyond the PC user base. The number of set-top boxes enabled with a modem for interactive services will increase from 1 million in 1997 to 29 million in 2003, in Europe. The majority of the installed base of set-top box modems will be PSTN ones, used by satellite and terrestrial operators. First-generation digital cable set-top boxes are also using PSTN modems, although in the long term many cable operators will change to use cable modems to make use of upgraded networks. It is predicted that not all of the homes with modems in their set-top boxes will enable them by plugging them into a telephone socket. However, this may change if set-top boxes are configured to work only if they are connected to a telephone line.

There is no standard specification for a set-top box as this is determined by the service broadcaster, who may sell, rent or give away the set-box box when a household subscribes to a particular service. Set-top boxes for receiving "free-to-air" satellite broadcasts can also be purchased independently, but they can cost twice the amount than those provided by the service broadcaster, as they would not be subsidised.

There are many different types of set-top boxes available across Europe. They vary according to two particular features:

Conditional access

Conditional access is the method by which the service broadcaster can control access to the bouquet of channels that are subscribed to by the viewer. When a viewer subscribes to a service they are usually provided with a smartcard that is inserted into the set-top box. It is also a useful way of controlling which regions of Europe are allowed access to particular programmes, allowing fees for intellectual property rights to be more finely tuned, thus perhaps reducing costs. The table (Figure 2.1) below lists the different types of systems available.

Figure 2.1 Conditional access systems in Europe




France Télécom








News Data System

Digicipher II

General Instrument

Conax CAS3

Conax Telenor

Source IDATE (5)

It is debatable as to whether the number of different conditional access systems causes problems or not. For the minority of households with more expensive steerable satellite dishes and receivers who wish to subscribe to more than one bouquet of offerings, across a range of satellites, different conditional access systems can cause difficulties. But for majority of households it is not a problem, as they will tend to only subscribe to one bouquet of offerings delivered via satellite, cable or digital terrestrial. If they decided to subscribe to more than one bouquet of offerings via different delivery systems they would still need a different type of set-top box.

Where more than one bouquet of offerings is available via the same platform, e.g. satellite, simulcrypt agreements have usually been reached allowing set-top boxes with different methods of conditional access to receive both bouquets of offerings. However, there is one notable exception - Canal Satellite and TPS in France - where no agreement has been reached for various commercial reasons. In countries where a number of bouquets of offerings are available, the operators have also tended to broadcast from the same satellite making it unnecessary to require a steerable dish.

Simulcrypt allows different decoders with different conditional access methods to decode different bouquets of channels from different service providers if the appropriate smartcard is present. However, this adds complexity to the service provider's equipment, as they will have to send more than one type of decoding signal. But it does allow the use of existing receivers without modification.

Another method is multicrypt transmissions that allow two different encryption systems to co-exist in the same receiver. The signal is sent sequentially through different conditional access modules that are in the set-top box. If the appropriate smartcard is present the viewer will be able to receive that bouquet of programmes. However, set-top boxes that are capable of using a number of different conditional access systems tend to be more expensive.

For the mass market most set-top boxes are generally rented or free to households who subscribe to a specific service operator but they are sometimes only capable of using the conditional access system of the service provider. This is a "trade off" for getting a cheaper but a proprietary set-top box. However, it does have an important impact of increasing the overall number of subscribers to digital services that could eventually reduce costs for both the subscriber and the service operator.

There have been early fears that proprietary set-top boxes with their own conditional access would cause restricted access to digital TV offerings. However these fears do not appear to have materialised (6). Market forces are likely to drive service operators to sort out any interoperability problems as they are more likely to have to bear the cost of replacing future generations of set-top boxes at no cost to the household. Future generations of set-top boxes will provide the more advanced interactive services that will become available.

Broadcasters also have the option of transmitting their channels on more than one platform depending on their target audience. Public service broadcasters will tend to offer their channels on a number of different delivery systems. For example, BBC Knowledge is available via satellite and terrestrial digital. Commercial operators would have to make a commercial decision as to whether they would offer an educational service on a number of different platforms.

It should also be noted that the vast majority of learning services are regional or national, but rarely, Trans-European in nature. The exception is specialised professional services that would be of high value thus the cost of buying any additional receiving equipment would be very small compared to the overall cost of the learning service. Therefore, any organisation wishing to offer a digital TV learning service for the mass market in the future needs use service operators who reach the majority of households they wish to target even though it may involve a number of different platforms. The costs of conditional access are already being born by each service operator.

Application Programme Interface

The application programme interface (API) is essentially the software operating system for the set-top box - in particular it controls the types of interactivity that are possible. A number of different systems are available in Europe as detailed in the table (Figure 2.2) below:

Figure 2.2 API systems in Europe



Open TV

Thomson Multimédia



Sun Chorus

Sun Microsystem

Power TV

Scientific Atlanta

DTV Navigator

Network Computer Inc.

Source IDATE (7)

Two APIs currently dominate the European market: Mediahighway, developed by Canal+, and OpenTV. These are proprietary systems that are not interoperable with each other or the Internet. Mediahighway has rolled out on the back of Canal+'s dominant digital pay-television services in France, Spain, Italy, Belgium, the Netherlands and Scandinavia. In contrast, OpenTV (8) has been adopted by British Sky Broadcasting and Open in the United Kingdom; Television Par Satellite, France Telecom Cable and Lyonnaise Cable in France; Telia in Sweden; TeleDanmark Kabel in Denmark; ViaDigital/Telefonica in Spain; Stream in Italy; and Multichoice in Greece, South Africa and the Middle East.

These designs of set-top box are being joined by new entrants including PowerTV from Scientific Atlanta and Navigator from NCI which are making modest progress in the cable sector. Microsoft also has aspirations to have its Windows CE operating system incorporated within a range of set-top boxes. There is also the MHEG5 design that is being developed under the auspices of MHEG - the Multimedia and Hypermedia Experts Group. Some broadcasters appear to be interested in using MHEG5 but most of the industry appears to want to move towards a Java-based standard.

The various APIs for set-top boxes are generally not an issue for a particular home user, as each tends to subscribe to only one service. However, the current set-top box installed base across Europe is fragmented between the different APIs - and these have differing levels of interoperability. Potential interactive television content providers are likely to be deterred from producing services if they have to develop them for a number of different software platforms even within one national market.

This is a very important issue for those planning to develop interactive learning services. They will be keen to offer their services through as many platforms as their target audience will use. This would result in additional costs and as new generations of set-up boxes become available there may also be additional costs for repurposing older courseware.

However, it is believed that the industry is aware of this particular problem and is starting to address it. It is likely that the differing APIs will migrate towards interoperability in line with the path set out by the Digital Video Broadcasting Group (9) (DVB) Multimedia Home Platform (MHP) standard, which appears to be moving towards a Java-based standard. This will include Internet standards, making different APIs compatible with each other and the Internet. Software interoperability will lead to increased development of interactive services on digital television platforms.


The development towards interoperability needs to be monitored carefully. If there are signs that lack of interoperability is acting as a deterrent to the development of interactive services, then some sort of intervention may be needed by the European Commission.


Digital Satellite

For those households receiving digital satellite broadcasts, a satellite dish is also required. This could be a fixed dish pointing to the appropriate satellite transmitting the digital broadcasts they want to receive. Alternatively, it could be a steerable dish - however, some satellite broadcasters claim that if the dish is not permanently pointing to their satellite, software upgrades to the set-top box may not be possible. The satellite towards which the dish needs to point varies from country to country. For example in Italy the two commercial digital satellite broadcasters Stream and Telepiů plus the public service operator RAI all use Eutelsat's Hot Bird II satellite. As a contrast, in the United Kingdom Sky Digital and the BBC use one of the Astra satellites.

Digital Cable

Digital TV broadcasts via cable are only possible if the house is in a area that can be connected to a cable network which is broadcasting in a digital format. The cable operator would usually provide the set-top box and would also make a simple connection to the cable network.

Most of the newer cable systems installed in Europe during the 1990s do transmit digital signals - for example, most cable networks established in the United Kingdom and Italy. However, some older cable systems available across most other parts of Europe may only currently be capable of transmitting analogue signals. Note that recently it has become possible to upgrade older cable systems to receive digital signals through a technique known as Hybrid Fibre Coax (HFC) as is happening in parts of Belgium and The Netherlands - but it must be noted that the main reason for upgrading the cable network from analogue to digital is to provide the home user with telephony and high-speed access to the Internet.

With the support of the European Cable Communications Association (ECCA) (10), a number of cable operators from across Europe have developed the Eurobox Platform (11). This concept is based on a common set-top box and a common API and Conditional access method. The box specification is used as a reference model by the cable industry and manufacturers. Viaccess has been selected as the conditional access system, whereas Open TV is the selected API, Application Programme Interface. The Eurobox Platform has been successfully implemented in France, Sweden and Denmark and is due to be implemented in the Netherlands during 1999. However, some cable operators, notably in the UK, do not appear to be following this platform in its entirety.

Digital Terrestrial

It is only possible to receive terrestrial digital signals to the home in the United Kingdom and Sweden at present - although other countries in Europe, notably Denmark and Spain, will soon start transmitting signals. These systems use an existing aerial, which has to be connected to the set-top box. The set-top box may be also connected to a telephone line to provide a return channel for interactive services.

In the USA the transition from analogue to digital TV is linked with the move from Standard Definition TV (SDTV) to High Definition TV (HDTV). This started in late 1998, with SDTV and HDTV being broadcast simultaneously. It is planned that all major cities will have terrestrial digital broadcasting by 2000 and by 2006 all stations are scheduled to be running all-digital services.

Field trials have also started in Japan and Singapore has started experiments this year.

Standardisation issues

Digital Broadcasting offers the potential for having more channels using SDTV - multi-channel Standard Definition TV - and/or for improving the resolution of pictures through HDTV - High Definition TV, using for pictures the global MPEG-2 digital compression standard. Unfortunately there is currently no global sound coding systems standard, resulting in a number of different digital television standards emerging from Europe, Japan and North America

Europe plus several other areas of the world have chosen to adopt the DVB - Digital Video Broadcasting - standard. This is available in a number of compatible versions: including DVB-S - for satellite transmission, the de facto global standard; DVB-C - its cable equivalent; and DVB-T - Europe's chosen digital terrestrial broadcasting system with services which started in the later part of 1998. The digital SMATV (Satellite Master Antenna TV) version - DVB-CS - has been adapted from DVB-C and DVB-S to serve community antenna installations such as for blocks of flats. Singapore has been conducting experiments with DVB-T and Australia has plans to adopt this standard.

The data-broadcasting version of the standard - DVB-Data - allows a wide variety of different, fully interoperable data services to be implemented. DVB-S satellite transmission of data is much faster than traditional telecommunication methods.

Figure 2.3 World-wide adoption of DTV standards, September 1998 (12)

Standards used in other parts of the world include:

Although both the ATSC DTV and the DVB-T systems use MPEG-2, they are different in a number of respects (13).

There is no interoperability between the CableLabs and ATSC and DSS standards, in other words MPEG-2 streams must be decoded and re-coded for jumps from one of these systems into another. Europe therefore has the key advantage of the interoperability that is featured as standard on all DVB systems for any delivery medium (14).

Integrated TV Sets

An alternative to the separate set-top box is currently an expensive integrated TV set that incorporates the set-top box. This integrated TV will also be a high definition TV (HDTV) in a 16:9 format - "pillar-box" - making it possible to view pictures in a wider format which is more natural for the eye, when that format is broadcast. However not all HDTV sets sold in Europe have integrated set-top boxes, because the 16:9 format has been broadcast in some countries over an analogue signal. However, in the USA HDTV sets were not introduced until the end of 1998 and do have integrated set-top boxes.

A number of manufacturers are now offering or preparing to launch Integrated Digital TV (IDTV) in the US or European markets, including Mitsubishi, Philips, Panasonic and Sony. So far, sales have been measured in thousands, while sales of digital set-top boxes last year reached over 8 million units.

However, there appear to be a mismatch in the consumer replacement rates for a TV, which typically is 10-15 years, compared to a set-top box, which is likely to have a 3-5 year time span as it is based on computer technology. This appears to be backed up by a report from Strategy Analytics which forecasts that by 2005, only 6% of US households will own an IDTV set compared to 63% with digital set-top boxes. In Europe, IDTV will hardly gain a foothold (15). The report considers that regular upgrades in technology and services, such as new software, devices and modems, mean that buyers of IDTV sets may be left with expensive but obsolete products. They consider a more prudent option is to buy a set-top box that can be replaced at minimal cost when upgraded services arrive. Service providers need to build audiences quickly, without waiting for consumers to replace their old TV sets, and are therefore likely to encourage sales of set-top boxes.

Development of Interactive TV

Television is considered (16) central to most people's domestic life and to their cultural, social, political and consumer awareness for billions of people throughout the world. "Television is everyday life." (17) But it has been primarily a medium that is passively viewed when the broadcaster wishes to make the programmes available. However, the videotape recorder has enabled viewers to record programmes and watch them when they wish to do so.

There have been many attempts over the years to develop interactive television (18). There were some attempts of interactivity during the 1970s with systems such as QUBE but they appeared to fail to offer a sufficient return on capital (19). The development of videotext or teletext services enabled viewers to have some form of interaction by choosing what information they wish to see. Although it is claimed by Teletext in the UK that 50% of TV viewers are also teletext users, some people have been put off by the poorer graphics, compared to what is on offer through the web. The development of digital teletext with its better quality graphics may redress this imbalance.

During the early to mid 1990s, the term "interactive TV" has been used to describe feedback from the viewers during live TV programmes notably those of an educational nature. These have tended to be pilot projects partially funded by the European Space Agency or the European Commission. Interactivity has been in the form of email, telephone calls or video link-ups via ISDN to presenters in the studio. It is commonly believed that Europeans have tended to see learning as primarily an interactive process. This is in contrast to viewers of educational programmes in the USA, and to viewers of distance learning programmes from open universities, who have found the "talking head" approach of a lecturer quite acceptable.

Unfortunately, those offering live interactive learning programmes have yet to show that they can produce sustainable services, particularly for home users. The number of interactions that are possible during a live TV programme is no more than, and perhaps less than, what can be offered during a face to face learning situation. However, the techniques utilised do offer the remote learner the potential ability to interact with the experts. Despite there being many experiments in this area a formula still has to be found as to what is the most appropriate learning experience for utilising these techniques in a sustainable way. The use of cheaper bandwidth through digital broadcasting is claimed to offer new possibilities but the case still has to be proven.

The mid 1990s have seen many expensive proprietary interactive television projects which it is claimed (20) "were set up, or at least publicised, by technology and network companies anxious to realise long standing science fiction dreams, bolster share prices and generate new revenue streams". Although many of these projects failed, they gave birth to huge numbers of other spin-off business opportunities that are only now starting to become commercially available. For example, video-on-demand services through existing telephone lines to the home have been proven to be uneconomic due to the lack of demand for the limited number of videos that could be offered. But it has been realised that the same underlying technology - xDSL - could be used to provide users with higher speed access to the Internet - an area where there is a pent-up demand. In fact this development could run in parallel and is very likely to compete with the next stage in the development of interactive TV.

Internet access via TV set

The late 1990s have seen developments towards accessing the web via the TV set, either using a set-top box or using a dedicated terminal. Although currently using an analogue set-top box, NTL (21) in the UK provide access to the Internet and other interactive services. NTL are currently testing the technology and market before they move to a digital platform.

A number of manufacturers have developed and are planning to market a device that provides access to the Internet directly via an ordinary television set. Connection is usually through a SCART socket on the TV set and also to an existing telephone line. The main thrust has initially been through WebTV (22) from Microsoft - still at a pilot stage in Europe but widely used in the US -with over 800,000 subscribers. But also from those that can provide a terminal, like the NetBox in France and Slipstream (23) in the UK.

The NetBox has been specially developed to offer Internet access via an ordinary TV set. It is based on software and hardware architecture developed by NetGem (24) - a privately-owned company founded in 1996 in Courbevoie, near Paris. It is claimed that the NetBox can be easily adapted to the needs of major telecoms operators, retailers, banks and media groups in Europe. In partnership with these corporations, the NetBox is currently being marketed across 15 countries in Europe, in conjuction with Alcatel (25) and France Telecom.

Slipstream has been developed by MSU (UK) Ltd (26) - based in Milton Keynes, UK. MSU develops consumer electronic products and reference platforms for itself and other companies. The SlipStreamTM Internet access technology enables anyone with a television and regular telephone line to access the Internet and send and receive email. When it is used with MSU's customised, proprietary browser, the device allows users to access and interact with foreign web sites in their native language. The company appears to have reached a deal with a Chinese manufacturer and distributor for production and sales to China and the rest of the world. Although personal computer penetration into Chinese households is low, it appears that China has an installed base of 320 million television sets, and that new television sales average 30 million units per year. Furthermore, an adequate Chinese telephone infrastructure is now in place in all 33 major cities and in most rural areas (27).

It remains to be seen how successful these devices will actually be in the European consumer market. A key issue is the quality of the fonts and graphics that can be displayed on an ordinary TV set, which will be of a lower resolution than a computer monitor. (There is much experience from teletext and videotex to build on.) The price of the device will also be critical, as it will need to be significantly lower than a home PC, a device that continues to drop in price. It is possible that these "Internet TV" devices will find a niche market - but a socially important one - for people that cannot afford to buy a home PC, on the basis that such people should be provided access to the opportunities of the Information Society, including learning opportunities.

If these devices are connected up to the telephone line using ADSL, it might be possible to access good quality streaming audio and video consisting of learning materials. If the device has enough memory it should be possible to cache the streaming video and replay it repeatedly. This could lead to opportunities for language learning or basic skills. Another possibility is that the device could be used for accessing resources from a local school or a community learning centre or even a local library via an Intranet. This may overcome some potential problems related to the maximum distance that ADSL can be used over an existing telephone line.


There is a need for a feasibility study into the potential usage of very low-cost devices linked to an ordinary TV set and an existing telephone line utilising ADSL technology to access local learning resources via an Intranet. This study must also consider the ability of people with PCs to access the same resources.

However, it should be noted, following the recent trial in the UK, it appears that Microsoft may not launch a WebTV service in Europe in the same way as it has done in the US. Although under the title of Microsoft TV it is likely they will primarily focus on client and server software packages working with service and content providers

Digital TV interactivity

With the development of digital TV, interactivity is now being understood to mean enabling millions of TV viewers to interact with programmes and services. The focus of this study is on this form of interactivity. Interactivity can be divided into two types:

The method of accessing interactive services is through the remote controller or a remote keyboard sending an infrared signal to the set-top box. The set-top box then requests that information is displayed on the TV if it is already stored in the set-top box or from regularly updated data re-broadcast on a carrousel basis, or the set-top box may request specific information via the "return" channel through an existing telephone line. This information may come back via the broadcast link or via the telephone line depending on what service is requested. Alternatively, with cable networks the request for data is sent via the cable system which itself is a two-way broadband system if the cable system is an advanced one.

"Enhanced TV" means that the viewer can do more than passively watch a TV programme. For example, they could be:

"Interactive services" involve accessing information independent of a TV channel. For example, it could mean:

Many of these services are also becoming available via the web. In fact interactivity through the TV and through the web are bumping alongside each other on an imaginary racecourse. But the finish to the race is not clear and the convergence of the technologies over time may mean they become integrated together before they reach the finishing line.

However, a key point needs to be made when comparing web-based developments with those of interactive TV. The web has evolved with end users having a lot of control over the content and what they want to select. They can also easily publish material themselves. Interactive services via the TV will develop in a more traditional manner, just like TV programming, where end users have not been involved in the innovation process and have not been able to express their interest in interactive services or systems through purchasing and use in the home (29). The impact of this on new interactive services has yet to be realised and will be a key factor on whether they will be able to compete with web-based services.

While many companies are racing to join the digital TV market, the potential of the technology is too new for standards to be in place for such elements as conditional access and EPG systems. This presents a dilemma for a manufacturer or designer who wants to be in the market, but is wary of starting out with what will become proprietary technologies or processes (30).

According to a report from Strategy Analytics (31) new technologies will let broadcasters offer interactive services which will bring consumers from their PCs back to their TV sets. It says the rapid developments in hard disk drive storage technologies will allow broadcasters to build new revenue streams from value-added interactive services.

The report identifies such US-based start-up firms as TiVo (32) and Replay Networks (33) as having pioneered these developments, which are now being supported by leading service providers and electronics manufacturers such as DirecTV and Philips. New advanced set-top boxes should start to appear on the market later in 1999, says the report, which also predicts that a high-capacity hard disk will become a regular feature in next-generation set-top boxes, allowing temporary or permanent storage of massive amounts of data, including high-quality video. Broadcasters will offer such services as "virtual VCRs", video-on-demand, and fast access to interactive information.

Strategy Analytics say the two main strengths of broadcasters in this interactive market of the future are that they:

The top of the range ReplayTV appliance from Replay Networks consists of two 13.7Gb hard disks capable of holding up to 28 hours of digital-quality video (34). Currently it retails at $1,499 but as the cost of memory continues to decrease this price will go down.

Movement towards "Personal TV"

This could lead towards the development of "Personal TV". Forrester Research (36) estimates that by 2004, 14 million Americans will be watching TV on personal video recorder (PVR) enabled sets and that by 2009, PVRs will penetrate four out of five US homes. Personal video recorders are consumer devices that use an intelligent interface and an internal hard drive to digitally record programming in anticipation of viewer demand. They could also be capable of holding 100 hours or more of programmes. With features like instantaneous fast-forward and reverse, the ability to pause live broadcasts, and easy-to-create viewer profiles, PVRs will broaden viewer options by offering, at any given moment, a menu of recorded programmes based on the viewer's preferences.

WebTV sees that personal television has three stages of evolution:

The development of devices that enable a person to customise TV viewing to a person's interest could fundamentally change the way the TV industry has operated over the last 50 years. Forrester expects viewership of TV advertisements to drop nearly 50% over the next decade, forcing advertisers to accommodate to this new environment. This could result in recognised brand names moving away from traditional advertising to increasingly sponsoring thematic channels - including learning channels. Or they could also move to an information mode of advertising where it becomes critical to be "captured" during key word searching through PVRs. This mode would not be dissimilar to web-based advertisements.

2.4 Other competitive technologies

The main competitive technology to interactive TV services is the Internet, and the World Wide Web in particular. A vast amount of information is readily accessible on the web to those that have a computer at home. Although it may not be particularly well structured, search engines and carefully indexed entry points known as portals are starting to make it easier to find specific information. Good quality audio is already available and reasonable quality video can also be accessed on demand. Currently there are limitations on the number of users that can access streaming video and the quality of the video but technical solutions to these problems are becoming available.

ISDN is already available to provide slightly higher speed access to the Internet than available over analogue telephone lines, but it is the developments with ADSL (Asynchronous Digital Subscriber Line) - and related technologies - providing high-speed access over an existing telephone line that will have a significant impact. These technologies will enable full-screen good-quality video and audio to be accessed via the Internet. This will make the Internet a very serious competitor to interactive TV.

Datamonitor expects that in the long term, video- and audio-intensive applications - which are likely to be selected and controlled through a Web interface - will rise considerably. At present, video/audio streaming accounts for 2% of Internet traffic. By 2003 Datamonitor predicts that this will have trebled to 6% (37).

Frost & Sullivan have also found that sales of video servers, which distribute video clips over the Internet, nearly doubled in 1998, reaching approximately $532 million. The rate of growth for such services, according to Frost & Sullivan, will reach 7.4% over the next six years - essentially making video-on-demand a serious competitor to the video cassette rental industry. They also see barriers to entry and to dominance, in particular: bandwidth capabilities, consumers not willing to invest in equipment that can adequately receive such clips, and expensive streaming technology. Current suppliers of this are Microsoft (Windows Media) and Real Networks (Real Player) (38).

Despite the potential barriers other new players are emerging to deliver video over the Internet. US based Tranz-Send (39) has developed a system for delivering DVD-quality films, TV programmes and software as compressed files that can only be used according to the terms stipulated by the copyright owner. The Tranz-Send technology uses software to distribute the files and uses a specialised player device to read the files on a computer or through a set-top box. It uses a proprietary system to compress files at a ratio of from 600:1 up to 1500:1 - compared to MPEG that can compress data at about 50:1. For a film like "Independence Day" it will currently take 150 minutes to download a DVD-quality video over a digital subscriber line and require about 1.4 gigabytes on a hard disk to store it. However it is claimed that the second generation of the technology, due out later in 1999 will take less than 15 minutes to download the file (40).

2.5 Key Players

The key players (41) in digital broadcasting have been identified as:

Some players may take on a number of these roles. Below is a list of key players who have been identified as having roles in providing digital TV learning services.

Content providers



The satellite carriers are:

The terrestrial digital TV carriers are:

Cable companies are:

Hardware suppliers

The main digital set-top box and satellite dish manufacturers in Europe are:

Software suppliers

Interactive service software developers

Management solution providers

Brokers or Agents



3 Information provided by Gilles Fontaine, IDATE, 25 May 1999

4 "Set-top box markets in Europe and the US: profit opportunities in digital TV", Datamonitor Report January 1999 - taken from press release "Digital television will bring interactive services to television across Europe", 11 January 1999

5 "Development of digital TV in Europe: Reference report/ 1998", IDATE Draft December 1998

6 "Development of digital TV in Europe, Reference report/ 1998" P69 Draft December 1998 IDATE

7 "Development of digital TV in Europe: Reference report/ 1998", IDATE Draft December 1998

8 OpenTv Web site:

9 DVB web site:

10 ECCA Web Site:

11 Web site for further details:

12 Source: 'World DTV Adoption' [online], September 1998, available at
Please note that Argentina has meanwhile adopted ATSC as standard for digital terrestrial TV.

13 RF Modulation: ATSC uses the single carrier 8-VSB modulation technology where DVB-T uses the multiple-carrier COFDM system. MobileTV using the 8-VSB system is impossible, and set-top antenna reception highly problematic. DVB-T is not only capable of both applications, but supports HDTV just as well as the US standard does.

Audio: The surround-sound audio system used by ATSC is the proprietary Dolby AC3 system, which offers no performance advantages over the DVB MPEG Layer II Audio system, which has the advantage of being an open standard.

Service Information: The ATSC system also makes use of a unique Service Information system, making interoperability between ATSC and DVB-T as infeasible as interoperability between ATSC and US cable and satellite standards.

14 European Public Policy for Digital Television, University of Hull, December 1998

15 "Set-top boxes and dumb monitors -- The impact of IDTV on the TV receiver industry", Strategy Analytics - taken from press release "Set-top boxes will dominate the home", 8 March 1999

16 Stewart, James. "Interactive television at home: Television meets the Internet - A new innovation environment for interactive television", Research Centre for Social Sciences, University of Edinburgh, United Kingdom, August 1998.

17 Silverstone, R. (1994). "Television is everyday life", London, Routledge.

18 Carey, J. (1996). "An Ethnographic Study of Interactive Television. ITV 96, Edinburgh unpublished and Carey, J. (1996). "Winky Dink to Stargazer: Five Decades of Interactive Television", I-TV'98: The Superhighway through the home?, University of Edunburgh. Both cited Stewart, James (1998).

19 Stewart, James, "Interactive television at home: Television meets the Internet - A new innovation environment for interactive television", Research Centre for Social Sciences, University of Edinburgh, United Kingdom, August 1998.

20 Stewart, James, (August 1998)

21 NTL Press Release "NTL launches UK's first Interactive TV service" 30 March 1999

22 WebTV web site:

23 Web Site for Slipstream:

24 NetGem Web Site:

25 Press Release "Alcatel and Netgem partner to provide Internet services on television sets", Paris, 25 March 1999 - found at

26 The Web site of MSU (UK) Ltd is

27 Press Release: MSU Corporation "MSU Corporation, an Internet Technology Company, Signs Manufacturing and Distribution contract in China - Agreement Marks MSU's Entry Into Chinese Market", Milton Keynes, England, 6 April, 1999

28 The term "teletext" is often used as a generic name for videotex but there is also a Teletext company involved in the developments of enhanced teletext. Their web site is

29 Stewart, James (August 1998)

30 Information from NTL Web Site

31 "Developments in technology set to bring TV audiences back", report from Strategy Analytics at

32 Web site of TiVo:

33 Web site of Replay Networks:

34 Article "VCR-PC hybrid adds up to interactive TV" by Robert Lemos, ZDNN, 17 December 1998

35 Replay Networks press release "Replay Networks, Inc, Launches New Era in Television Personal TV Leader Ships Award-Winning ReplayTV", 26 April 1999

36 Forrester Research press release "Personal Video Recorders will bring Fundamental changes to Television Networks", 24 March 1999

37 "The Future of the Internet", Datamonitor Report March 1999 - taken from Press Release "Online population set to top 250 million in the next five years", 1 March 1999.

38 Interactive TV, April 15, 1999, Issue 1.91

39 Web Site of Tranz-Send:

40 "Net Video Coming of Age?" by Christopher Jones - article in Wired News, 29 March 1999

41 Based on some categories identified in the report "Digital Broadcasting: the Competitive Challenge for Telcos and Cable Companies", by John Moroney and Thomas Blonz, Ovum, September 1997