In a method of providing a caller with a pre-stored sound chosen by a
called subscriber instead of a standard RBT (RingBack Tone), an HLR (Home
Location Register), when a location request message is received from a
call-originating exchanger, furnishes either the call-originating
exchanger or a call-terminating exchanger with information on whether or
not an RBT is to be replaced for the called terminal. The
call-originating exchanger or the call-terminating exchanger then
searches, while a trunk connection is established between the exchangers,
for a sound code assigned to the called terminal based on the information
furnished by the HLR, and provides the caller with a pre-stored
RBT-replacing sound associated with the found sound code as an RBT.