Method for setting substitute tone of ring-back-tone of sender to substitute tone of ring-back-tone of accepter in mobile communication system using substitute tone of ring-back-tone

PURPOSE: A method for setting a ring-back tone alternative sound of a caller to a ring-back tone alternative sound of a receiver in a mobile communication system using ring-back tone alternative sounds is provided to enable a caller to set a ring-back tone alternative sound of a receiver to a ring-back tone alternative sound of the caller when calling the receiver through a mobile communication terminal, thereby supplying various ring-back tone alternative sounds to subscribers. CONSTITUTION: An HLR searches a specific additional service of a receiver(S100), and decides whether the receiver is registered in a ring-back tone alternative sound service(S101). If so, an IP(Intelligent Peripheral) requests a CRBT(Cellular Ring Back Tone) server to transmit sound source code information on a ring-back tone alternative sound preset by the receiver(S103). The CRBT server searches the requested information from a database, and transmits the detected code information to the IP(S104). The IP finds the ring-back tone alternative sound of the receiver, enables a caller to listen to the sound(S105), and detects whether a specific key is inputted from the caller(S106). If so, a bringing server requests a COIS(Customer Oriented Information System) to confirm a ring-back tone alternative sound service of the caller(S108), and decides whether the alternative sound of the caller is registered(S109). If so, the bringing server stores a telephone number of the caller, the code information of the receiver, and predetermined conditions in the database(S111), and transmits stored results to a terminal of the caller(S112).