Clearly, there is a whole range of facilities and possibilities serving basic needs of disabled people, ranging from straightforward use of ordinary equipment to development of special devices and facilities. An ordinary voice telephone can often be used by people with slight hearing impairments, but with a built in variable amplification and an inductive coil for connection to hearing aids a much larger market of hearing impaired people is available. For more severe hearing or speech impairments text telephones are a more realistic solution, and for people who are pre-lingually deaf and use Sign Language, video phones are necessary. But in order to be able to communicate from such terminals to voice telephones and get access to service facilities in general, a conversion facility is needed. Manned relay centres fulfil the needs for translation between voice and text and Sign Language.
Companies often have doubts about that figure, and tend to lower it considerably.
As soon as the condition for Universal Service is limited to rather small adaptations of equipment and facilities most providers seem to be interested. For example most telecom operators today seem to be aware of the benefit of well designed, standardised key-pads. Most also realise that some basic telephones with built in variable amplification and inductive loop for hearing aid users will widen their market. But sometimes there are possibilities to utilise market forces even for rather expensive devices. An example is the provision of public text telephones, which is a problem to all operators in Europe today.