What Should Disabled People Expect of OFCOM?
Tony Shipley and John Gill
APPENDIX
Technology Platforms
The convergence of telecommunications, broadcasting and information technology coupled with the increase in speed of transmission of data will have significant impact on domestic consumers in the next few years. Also reductions in price will make services more widely available and not just restricted to the business sector.
Telecommunications
From the consumer's viewpoint, fixed line telephony has changed little over the years despite considerable changes in the underlying technology. The quality of the audio signal has improved which has benefited many hard of hearing users.The traditional telephone system was designed for transmission of audio, and there have been problems in adapting it for the transmission of text. This is particularly significant for deaf users who rely on the text relay service to be able to communicate with non-text users. The separation of regulations for the network and the terminals has caused problems for disabled users interested in end-to-end communication. In many cases, facilities required by disabled users involve adaptations to both the terminal and the network.
The introduction of inexpensive fax systems opened up new possibilities such as remote reading services for blind people. However it is the introduction of greater bandwidth that opens up the possibility of many new services if the charges are at an affordable level. ISDN (integrated system digital network) has not had a significant impact for the domestic market in the UK since it was priced too high. The initial domestic markets for broadband services are likely to be centred around faster access to the Internet and the ability to download video (ie video on demand). One approach has been to use the conventional telephone lines to transmit ADSL (asynchronous digital subscriber line); this is limited to users who live near a telephone exchange which has the necessary equipment to handle ADSL. As yet the market penetration has been low since the availability has been very limited and the prices set higher than many domestic customers are prepared to pay; this situation is likely to change in the foreseeable future.
Broadband services to domestic consumers can also be provided by cable television companies. However the available bandwidth is limited by the capacity of the cable infrastructure when it was installed. In remote parts of Scotland, BT are using satellite systems to provide broadband services at up to 512 kbits/sec; the costs are higher than fixed line links but in some areas it is not viable to lay the necessary cables.
Broadband services can include video telephony which is of great potential use for many deaf people. For sign language transmission, the picture has to be refreshed at least 25 frames per second. Lip- reading requires a high definition display. Video telephony has been found to be helpful to reduce the isolation of intellectually impaired people who live independently.
Ten years ago only a few businessmen lugged about heavy expensive mobile phones. Nowadays no self-respecting teenager is without their mobile which can be customised (both facias and ringing tones) to suit the image required, but these phones are often mainly used for text messaging. In this fast changing market, the needs of people with disabilities have been given low priority by the manufacturers and network operators.
Mobile telephones increasingly require the user to read a small liquid crystal screen to operate many of the functions in the phone. Although the phones incorporate increasingly powerful microprocessors, manufacturers have not seen a commercial opportunity in providing models which incorporate speech output of the messages normally displayed on the screen. However there are some indications that this may change because car drivers are seen as a significant market segment.
The first generation of mobile phones were analogue and often prone to interference. Commercial take-off did not happen until the introduction of the second generation digital systems. As a result of European collaboration, a common standard was agreed; the GSM (global system for mobile communications) system is now used in 174 countries - the notable exceptions are the USA and Japan (and the USA is increasingly adopting the system).
One operator realised that it would be possible to send short text messages over the GSM system without any new infrastructure, so they offered the service to their customers for no charge. They little realised that this would end up being a major revenue earner. The annual UK rate is now about ten billion text messages; at 10 pence a message, this corresponds to an income of a billion pounds per year!
The next development was to provide access to text-based information services. WAP (wireless application protocol) was launched with a blaze of publicity with the expectation that consumers would flock to buy the new phones and pay handsomely for the services. WAP has been a commercial failure. The service was far too slow and the information services very limited. However in Japan a similar system, I-mode, was a commercial success since the price was kept very low and a large range of information services provided.
The failure of WAP is not deterring the network operators from planning to launch new mobile services for the transmission of data (rather than just voice communication). Data can be just text, text plus graphics, still pictures, or video. The initial target is to offer access to the Internet while mobile. The major question is whether there are sufficient consumers prepared to pay premium rates for such a mobile service.
GPRS (general packet radio service) is a high speed packet data technology which will permit data transmission speeds of up to 100 kbit/s over the GSM network. This is well suited for frequent transmission of small amounts of data. However it could be overtaken by UMTS (universal mobile telecommunications system).
| System | Maximum speed kbits/sec |
| GSM | 9.6 |
| GPRS | 100 |
| UMTS | 2000 |
UMTS is the next (third) generation of mobile telecommunications system which will provide high speed access to the Internet with data rates of up to 2 Mbit/s, but a tenth of this rate is likely to be typical when outside a city centre. In the UK the network licences have been sold by the government for vast sums (the first five licences sold for over £22.5 billion) which will have to be recouped from the users.
UMTS will permit the transmission of video images. Someone with an intellectual impairment can have problems when their routine is disturbed, such as public transport being disrupted; in this case, they might want to contact a service centre who could guide them to alternative transport using the video link. Another possible use for UMTS would be to download talking books during the night; a typical novel might take about 20 minutes to download.
Plans for fourth generation systems to be operational by 2010 are beginning to be discussed publicly. An interesting and most welcome feature is that access by people with disabilities is being considered - an aspect which was notably lacking in the earlier generation plans.
In recent years there has been a dramatic increase in portable electronic devices for individual use. These include mobile phones, laptop computers, digital cameras and PDAs (personal digital assistants). PDAs started as electronic calculators which also incorporated facilities for storing addresses and telephone numbers; they have now become much more sophisticated and incorporate features which are more commonly associated with a personal computer.
However there has been a problem in that these devices have not easily communicated with each other. So the user may store an address and telephone number on a laptop computer, but it has to be keyed in again on the mobile phone. To overcome this problem manufacturers provided cables to connect systems together. Unfortunately, with no single standard interface, each pair of systems needed a separate cable.
For some applications the USB (universal serial bus) became the standard interface, thus reducing the number of cables required. Since it was still fiddly to interconnect devices, wireless systems were developed as a cable replacement.
The first widely used wireless system was infra-red (as used in a television remote control). This had a range of about 3 metres and required line of sight between the two devices. However a significant problem was that there were slight differences between manufacturers so one could not be certain that a device from one manufacturer would work reliably with a device from another.
The laptop computer industry then developed a short-range radio system (IEEE 802.11b) primarily for connecting portable computers to local or metropolitan area networks. This means that a businessman could move about his office building and always be connected to the office computer network. A metropolitan area network is an extension of this concept to shopping centres and airports.
BT has announced plans for 400 public access wireless local area networks by June 2003, and up to 4000 sites by June 2005. The access points will be at hotels, railway stations, airports, bars and coffee shops. They estimate that users will be able to access the Internet at speeds of up to 500 kbits/sec which will be faster and significantly cheaper than UMTS.
This system was unsuitable for mobile phones since it used too much electrical power, and so would drain the relatively small battery too quickly. Also it was not perceived to be sufficiently secure for applications involving financial transactions. So the industry developed the Bluetooth wireless system.
The manufacturers of domestic electronic equipment were also interested in using radio signals to interconnect systems from audio systems to heating controllers. So they developed HomeRF which was seen as an inexpensive method of installing smart housing features in an existing house. For instance, the action of locking the front door from the outside could trigger a message reminding you that a window has been left open or the cooker is switched on.
All three of these systems work in the same frequency band (see table) but are incompatible. In practice the maximum data rate is likely to significantly less than the figures shown.
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These radio systems are of interest to people with disabilities since they greatly ease the problems of interconnecting assistive devices to mainstream equipment. In addition they open up the possibility of a range of new services to help disabled people.
For instance at a cash dispenser, the user's card could instruct the machine to send speech output to a particular mobile phone handset. So the text on the screen of the cash dispenser would be presented as speech in a specific mobile phone handset. This does not involve a phone call, but just uses the handset which includes a Bluetooth interface.
Another potential application is to use the Bluetooth-enabled mobile phone handset at a light-controlled pedestrian crossing. Disabled persons, from their handset, could indicate that they want to cross the road and need more than the standard time to complete the crossing. Related applications include audio information about road names or the destination of buses.
As mentioned earlier the main technological contenders all work in the same radio band at 2.4 GHz. This band is getting congested since it is already used by some microwave ovens. Therefore there are plans for the next generation to operate at 5 GHz which will also give the ability to transmit at higher data rates.
The push for higher data rates comes from companies involved in digital television. The government wants to turn off analogue television broadcasts sometime between 2006 and 2010; the urgency is that they want the radio frequencies for the mobile phone networks. Before the analogue broadcasts are turned off, the consumers must be able to receive digital television. This is not just the television set in the sitting room, but also the ones in the bedrooms (the UK has an average of 3 television sets per household). Rather than having to purchase multiple set-top boxes, the consumer would find it advantageous to have one set-top box and a short-range radio connection to the other television sets in the house. This is a major application for systems with higher capacity such as Hiperlan2 and IEEE 802.11a.
For the mobile handset manufacturers, product shelf life is measured in months not years. So they are not too concerned about changing to another frequency in a few years' time. However for the pedestrian crossing application mentioned earlier, it will be a serious flaw if after a few years one could no longer purchase a compatible telephone handset. So we could end up, yet again, with technological systems of significant potential benefit to people with disabilities, but which are not implemented for unrelated commercial reasons.
Broadcasting
Up to five years ago, all television and radio was transmitted in analogue form. This resulted in variable quality signal reception and was inefficient in use of radio spectrum. There is increasing demand for radio spectrum, particularly from mobile telecommunications, so governments wanted to be able to sell any unused frequencies.
Digital television is about four times more efficient in its use of radio spectrum, and has the capability for supporting many value-added services. In principle the picture quality should be considerably better than analogue transmission, but the broadcasters have chosen to opt for more television channels at the expenses of picture quality.
With analogue transmissions there is a gradual reduction in picture quality with increasing interference of the radio signal. With digital systems, the quality remains constant until the increasing interference causes a sudden loss of picture; this is similar to the situation with digital audio compact discs compared with analogue vinyl long-playing records. At what point there is loss of a digital picture will depend on the strength of the broadcast signal and the number of different paths by which it is reaching the receiving aerial (eg by reflections from tall buildings). In the UK, one problem which needs to be resolved is that the power levels for transmission of digital terrestrial television were set too low, and there are problems in modifying the transmitters to boost their power output.
Instead of using terrestrial transmission, it is possible to transmit via a satellite. BSkyB now only transmits digitally with a choice of about 200 channels. Consumers need to install a satellite dish, which is only viable for fixed installations; portable and mobile receivers have, in practice, to utilise terrestrial transmission.
The third option is cable. This option is only available to those areas for which the cabling has been installed in the immediate vicinity. In practice this meant that cable is restricted to areas with high population densities. In the UK, the cable option has a low take-up since it was not widely available until after satellite services were well established. In some other countries, cable has a significantly higher market penetration.
In the UK, up to recently, terrestrial digital television offered both free-to-air channels and the option of paying for extra channels. The demise of ITV Digital (formerly called On Digital) has meant that terrestrial broadcasts are solely the free-to-air channels which are fourteen compared to the five on analogue television.
On analogue television, subtitling is transmitted using the same system as Teletext. On digital terrestrial television similar subtitling is provided but with a more legible typeface. On pre-recorded programmes the text box is positioned to avoid obscuring the essential parts of the action on the screen.
It is increasingly important to be able to read on-screen displays which vary from setting options, such as subtitles, to electronic programme guides. There is a need to be able to customise the presentation of this information to suit the individual - this may be larger characters on the screen or some form of non-visual output. One possibility would be to store the user's preferences on a smart card.
Interactive television is a term used to describe a range of different services, from choosing camera angles for a sports event to calling up text to supplement a broadcast programme (eg the recipe in a cooking programme). In some cases the processing is downloaded to the television set or set-top box, then there is no requirement for a return path to the broadcaster. In most cases there is a need for a return path which is simple to arrange with cable television, but usually requires a telephone connection for terrestrial or satellite broadcasts. With most interactive television systems the majority of the data is going from the broadcaster to the consumer with a very small amount of data on the return path.
The government has announced that its services will be available electronically and that interactive television will be the preferred mode for non-computer users. However many people with disabilities have accessibility problems with current interactive television services. Research needs to be funded to develop appropriate accessibility solutions which will involve design modifications to the terminal, network and content presentation.
The Internet can be used as a system for delivering multi-media so it will compete with traditional telecommunication and broadcasting services once the bandwidth is available at reasonable cost. Traditionally the Internet has had a minimum of regulation, and it has not been affected by national boundaries. One result has been consumer reluctance to make payments over a system which is perceived as insecure, to an organisation of uncertain geographic location. In the case of telecommunications and pay-to-view television, payments can be handled by the service provider so lessening the risk to the consumer.
The use of electronic purses (ie cards which can be pre-loaded with money) has been promoted as a method for handling low value transactions. However consumers have not been convinced, so electronic purse systems have not reached a scale where they are commercially viable.
The technology for recording broadcast material is changing fast. In the past, domestic consumers have been limited to recording on magnetic tape (usually in the VHS format), but the advent of large capacity low cost hard disks will offer a range of new facilities. For instance, with a hard disk system, it is possible to simultaneously record and watch a programme; this means that you could stop watching a programme for a few minutes, and then continue watching from where you stopped. It also means that the recorder could be programmed to playback omitting all advertising breaks.
What is certain is that there will be significant
technological changes in the next few years. Which of these developments
will have significant market penetration will depend less on the technology
than on commercial factors such as pricing. However the challenge will
be to ensure that the new systems and services are designed from the outset
to be usable by as many potential users as is reasonably possible.
Published by Royal National Institute of the Blind
in collaboration with PhoneAbility
ISBN 1 86048 028 4
© Copyright reserved, 2002.
Last updated: 20.11.2009 © Copyright reserved Website design: Digital Accessibility Team