H04M3/42—Systems providing special services or facilities to subscribers
H04M3/487—Arrangements for providing information services, e.g. recorded voice services or time announcements
H04M3/493—Interactive information services, e.g. directory enquiries ; Arrangements therefor, e.g. interactive voice response [IVR] systems or voice portals
Dispositif electronique independant ou integre a un poste telephonique, permettant de determiner tout en le visualisant le cout des communications telephoniques