COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To provide a communication system that discriminates propriety of a communication state of a communication path. SOLUTION: The system includes a transmission station 2 that receives speech data sent from a caller telephone set 1 and sends the data to a called telephone set 8 via an Internet B and a called station 5 which receives speech data sent from the transmission station 2 via the Internet B and sends speech data to a called telephone set 8. The communication state is discriminated by sending/receiving a packet between the transmission station 2 and the reception station 5. Furthermore, a clock signal is given to the transmission station 2 or the reception station 5 to monitor the time of reply from the reply request to other station or the terminal equipment thereby discriminating the communication state.