This technology makes it possible to use any make of telephone to call any person, who also has an arbitrary make of telephone, via the world-wide telephone network.
Telcos actually supply a 'dial tone' service.
This means that wherever I have a dial tone, in other words a connection is available to me, I can make use of a piece of equipment like a telephone, and of the services that the telecommunication network makes available. This principle enables these companies to manage their networks, which often have millions of telephones, with ease. Telcos are thus the suppliers of dial tone with the same reliability as utility companies supply a 'gas tone', a 'water tone' and an 'electricity tone'. The next step for telcos will thus be to supply a 'data tone'. This process will be speeded up by the deregulation of the telecommunication market, which will force the telecommunication company to distinguish itself in the market on the basis of its innovative services and its customer service.