Method of Delivering Instant Messages for Portable Phone Users

PURPOSE: A method for transmitting an instant message to a wireless terminal user is provided so that an IM(Instant Messaging) service user instantly transmits the message to an object who is not logged in an IM server. CONSTITUTION: An IM server judges a corresponding recipient as a wireless service user from a user DB, and requests an IM gateway to transmit a message(200). The IM gateway converts an instant message into a short message, and requests an SMSS(Short Message Service Server) to transmit the short message(202). The SMSS transmits the short message requested by the IM gateway to a mobile phone(204). If the transmission of the short message is completed, the SMSS reports the transmitted result to the IM gateway(206). The IM gateway reports the transmitted result to the IM server(208). The mobile phone transmits an answer to the SMSS(210). A wireless telephone network routes the answer to the IM gateway with reference to a company identification number of a telephone number of the recipient(212). If the last sender ID is confirmed, the IM gateway converts an answer short message format into an instant message format, inserts the last sender ID into a recipient ID, and transmits the answer message to the IM server(214). If the answer message is received, the IM server transmits a reception acknowledgement signal to the IM gateway(216). The IM gateway transmits the reception acknowledgement signal to the SMSS(218).