Arthur Orbell, the technical director of Oftel, said that within a few years specially developed telephones would be able to distinguish between incoming signals on a telephone line and translate them so that the telephone makes the correct ringing tone for the person being called. 'The phones could shout for you,' he said.
The proposals for new numbering and the services they could make way for are outlined in a consultative paper issued by Oftel. They build on the National Code Change, due in 1995, which will prefix a '1' to every existing telephone number. Thus central London numbers will begin 0171 and the code for Derby would be 01332 instead of 0332.
Under Oftel's proposals the expanded system will be exploited to create extra sets of numbers for new services by swapping the initial '1' with another digit. All personal lifetime numbers would begin '02' rather than '01' and all mobile numbers would begin '03'. Services with special tariffs such as premium rate would begin '08'.
Don Cruickshank, the director general of Oftel, said: 'We want a stable and understandable numbering system to take us into the 21st century. Who knows where technology will lead, so we need a flexible system with enough numbers to cope.'
Mr Cruickshank said that one company had already applied for a licence to offer personal telephone numbers and others were interested. Computer databases would be fed with information on the whereabouts of people at a given time and software would track down their position on the network when someone calls their number.
Mr Cruickshank said that in spite of an expected explosion in new services, the standard number system would not be changed once the new '1' prefix is added in 1995. The expansion is to add new possibilities rather than to force change on people who did not want it, he stressed.
As a first move, Oftel hopes that by next year existing telephone numbers could be swapped between services so that people changing from BT to another service or vice versa can keep their number. BT's major rival, Mercury, and new telephone operators such as cable television companies have been lobbying for this 'portability' for some time.
Mr Cruickshank said: 'There is no doubt that these changes are essential for UK customers if they are to benefit from competition in the industry. It is crucial that these issues are debated as widely as possible.'
Oftel wants views on the consultative document within two months. Mr Cruickshank said that he will then press on with definite plans.