| 摘要 |
PURPOSE: A system for notifying communication possibility states, apparatus therefor, and method therefor are provided to reduce additional service providing costs by providing resources for providing additional services in a circuit service. CONSTITUTION: In case a reception terminal session connection is impossible, an additional service control unit(110) confirms the communication possibility state of a reception terminal(402). The additional service control unit transmits a communication possibility notification message or an ineffective communication notification message. A reception terminal communication state is notified to a calling terminal(401) by using a communication possibility notification message. An ineffective communication request is notified by using the ineffective communication notification message. |
