Abstract: An apparatus and method for displaying menu items of a hierarchical menu on a screen in such a manner that a function desired by a user can be traced and performed with a minimum number of key inputs. The top-level menu and bottom-level menu of the hierarchical menu can be simultaneously displayed in one screen picture, thereby enabling a user to reach from an upper-level menu to the bottom-level menu or from the bottom-level menu to the top-level menu with a minimum number of key inputs without passing through intermediate-level menus. Further, a certain menu can be displayed in one screen picture along with the one-level upper menu and one-level lower menu thereof or the one-level lower menu thereof so that the user can readily recognize the position of a current menu. Furthermore, the user can access all menus using only direction keys.

Abstract: A method and system for guaranteeing a seamless session when replacing a PoC terminal in a PoC system is provided, in which a currently busy PoC client can be replaced in an existing busy PoC session using a PoC compliant client capable of connecting the PoC session, thereby preventing a transmitted media stream of the running PoC session from being lost when the PoC client is replaced. The method includes transmitting, by an arbitrary PoC user, a message for replacing a terminal from a user terminal to a session management server while maintaining the session; receiving, by the session management server, the replacement request message, and transmitting an INVITE message to a terminal to be replaced, or a target terminal; and receiving, by the target terminal, the INVITE message, and media through an existing session. In a situation where there is a need to replace the PoC terminal according to change of the media for the PoC call, request of mobility, etc.

Abstract: A method and system for guaranteeing a seamless session when replacing a PoC terminal in a PoC system is provided, in which a currently busy PoC client can be replaced in an existing busy PoC session using a PoC compliant client capable of connecting the PoC session, thereby preventing a transmitted media stream of the running PoC session from being lost when the PoC client is replaced. The method includes transmitting, by an arbitrary PoC user, a message for replacing a terminal from a user terminal to a session management server while maintaining the session; receiving, by the session management server, the replacement request message, and transmitting an INVITE message to a terminal to be replaced, or a target terminal; and receiving, by the target terminal, the INVITE message, and media through an existing session. In a situation where there is a need to replace the PoC terminal according to change of the media for the PoC call, request of mobility, etc.

Abstract: The system includes a push to talk over cellular (PoC) client for requesting storage of media data of a sub-participation session among the simultaneous sessions, a storage part for storing the media data of the sub-participation session, and a push to talk over cellular (PoC) server for transmitting the media data of the sub-participation session stored in the storage part to the push to talk over cellular client according to a read out request of the push to talk over cellular client.

Abstract: Disclosed is an apparatus for monitoring a multisession including one-to-one calls and group calls at a same time in a wireless communication system performing group communication. The apparatus includes an intermediate unit, a control unit and a text conversion unit. The intermediate unit receives a request message for a monitoring set up from a user terminal, manages sessions correlating with each user, and intermediates a voice message received from each of the correlating sessions. The control unit confirms a session and a set session monitoring method of the voice message received from each of the correlating sessions, and transmits the received voice message according to a result of the confirming. The text conversion unit converts the voice message into a text form, when the voice message is in an inactive session and the session monitoring method is set to use text.

Abstract: An apparatus and method for displaying menu items of a hierarchical menu on a screen in such a manner that a function desired by a user can be traced and performed with a minimum number of key inputs. The top-level menu and bottom-level menu of the hierarchical menu can be simultaneously displayed in one screen picture, thereby enabling a user to reach from an upper-level menu to the bottom-level menu or from the bottom-level menu to the top-level menu with a minimum number of key inputs without passing through intermediate-level menus. Further, a certain menu can be displayed in one screen picture along with the one-level upper menu and one-level lower menu thereof or the one-level lower menu thereof so that the user can readily recognize the position of a current menu. Furthermore, the user can access all menus using only direction keys.