john Gill technology header image

Mobile Telephony: Will Future Developments be Accessible to Visually Impaired Users?

Dr. John Gill
June 2000

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.

Problems with mobile phone displays are not limited to blind people. The ageing process has significant impact on vision. For instance with an average person aged 60 only one third as much light reaches the retina compared to a person aged 20. This has implications for illumination levels and the ability to read low contrast displays. Accommodation is the ability of the eye to change its focus, and thus get a clear image on the retina. The gradual decline in accommodation is called presbyopia, and is inevitable with age. Another effect of the ageing process is that it becomes harder to multi-task. Unfortunately designers of new systems and services often appear unaware of these aspects of ageing and are thus surprised by the low take up of their systems by older people.

The SIM (subscriber identification module) card in a GSM (global system for mobile communications - the digital mobile system) phone can be used for providing interaction with internet and other services. This will not involve true browsing, but will include 'push services' such as checking train times, booking theatre seats and restaurant tables, traffic news services and purchasing.

Considerably more functionality will be available with WAP (wireless application protocol) which will facilitate financial transactions such as reloading an electronic purse. Digital signatures and encryption can reside on the phone itself, in the SIM chip, so there is no need for an additional smart card for authentication of transactions. However problems in agreeing a common standard for the smart cards may mean that the phone will need to incorporate two card readers.

Extra functionality to suit visually impaired users could be built into the terminals, but this in itself is unlikely to provide full access to services. Therefore it will be necessary to modify the server or proxy server. The WAP User Agent Profile Specification covers aspects of the technical interface (eg the technical capabilities of the terminal) and the User Preference Profile concerns content selection (eg the user is interested in receiving sports scores). Neither of these profiles covers the needs of people with disabilities.

This could be done in the form of a user profile which is stored on the smart card in the user's phone. There is already a European standard EN 1332-4 for storing user preferences on a smart card, but this will need to be extended to allow for the facilities needed by mobile phone users who have disabilities. This standard already incorporates facilities for specifying preferred text size, screen colour, colour avoidance, voice output, and interface complexity.

General Packet Radio Service (GPRS) is a high speed packet data technology which will permit data transmission speeds of up to 100 kbps over the GSM network. This is well suited for frequent transmission of small amounts of data. However it could be overtaken by UMTS.

UMTS (universal mobile telecommunications system) is the next generation, after GSM, of mobile telecommunications system which will have seamless operation between terrestial and satellite links. It will provide high speed access to the internet with data rates of up to 2 Mbit/s for a stationary terminal, less when on the move. It will include packet data transmission with the potential to adjust bandwidth on demand for asymmetric traffic. It operates in the 2 GHz band so it will require many more sites than GSM. In the UK the network licenses have been sold by the government for vast sums (the first five licenses sold for over 33 billion Euros) which will have to recouped from the users; this may make the license holders reluctant to provide reduced rates for special services for disabled users.

These special services might include:

  • Remote guidance whereby a visually or intellectually impaired person could transmit a picture of their location to a service centre, and receive audio information on how to reach their destination.
  • Downloading of talking books during the night. A typical novel would take about 20 minutes to download using MP3.
  • Remote Sign Language interpretation.

A major problem is the desire of the regulatory bodies to keep the network completely separate from the terminals. For many disabled users, what is important is the end-to-end connection and whether the service meets their needs. In many cases, it is going to require a combination of facilities in the network and on the terminal, and there will be difficulties in getting universal service for people with disabilities while there is the regulatory separation of network and terminals.

Helmut Stein, Nokia's chief technical officer, predicts that the mobile phone will develop to become the new 'remote control' for televisions, and will be the interaction channel to the service provider via GPRS / UMTS and to the television via Bluetooth.

Bluetooth is a short range wireless radio link that can be built into a microchip. It offers data speeds of up to one million bits per second and can be used for transmission of voice and data, including still images. Its operating range is 10 metres which can be extended up to 100 metres using additional amplifiers. Bluetooth uses powerful encryption and frequency hopping at 1600 times per second.

Bluetooth offers the possibility of connecting special user interfaces to mobile phones as well as a range of domestic equipment. As yet, the assistive technology industry has not shown interest in this area.

Interactive television is attracting considerable investment as it is seen as a significant step in selling new services to customers who may not be computer users. The UK government envisages that it will be a major method of interaction between the public and the government within five years.

Traditional television can be characterized as one-to-many whereas the internet would be characterized as many-to-one. As yet interactive television is frequently just an enhanced one-to-many system with uncertainty as to how to satisfactorily also be a many-to-one system.

Various companies are already offering interactive television services in the UK, and many more are planning to launch services in the next year. The services vary considerably depending on the main service being delivered:

  • Video on demand systems typically use ADSL (asynchronous digital subscriber line) to download films. Some also offer electronic shopping but this operates as a series of video clips.
  • Enhanced television programmes where additional information can be provided (eg recipes with a cooking programme, special offers linked to an advertisement) on screen alongside the broadcast.
  • Some systems also offer Email:; this is proving popular among those who do not have access to a computer or have no inclination to use a computer. This is likely to encroach on the market for mobile services offering similar facilities.
  • Web access. Some systems are limited to a 'walled garden' of websites, but customers have not been entirely happy with this restriction; there may be lessons here for WAP operators offering mobile access to WML websites. Unrestricted access to the web has problems in that some websites require a browser running on a computer; the current generation of set-top boxes contain limited processing power. However, in the UK, home shopping has taken off faster on interactive television than on the web; this is being attributed to viewers being less anxious about credit card fraud through the television set than the computer.

However these technological developments may be largely inaccessible to visually impaired users. The approach of the European Commission is to leave all aspects of the user interface to the commercial providers to decide for themselves without reference to standards bodies or national regulators. Therefore there are limited means left to the disability organisations to influence the system developers and service providers since the European Commission does not appear to be planning to introduce legislation to protect the needs of disabled people.


John Gill Technology Limited Footer
John Gill Technology Limited Footer