The internet call systems using CTI(Computer Telephony Integration) functions are designed with system configuration, DFD(Data Flow Diagram) and ERD(Entity Relationship Diagram) in this paper. The internet call systems are constructed to cooperate with conventional CTI call center. The internet phone calls occurred from the web browser of customer can be connected throughout VoIP gateway and PBX to many counselors. The internet call systems can provide various services; customer information service, escorted browsing service, text chatting service, text sharing service, conference service, and statistical analysis service.