The international and domestic revenue keep growing constantly, and nowadays the international casino game industry is getting upgraded utilizing IT technology. In contrast, due to many constraints and limitations, Korean IT society has not paid attention to the casino IT area. Slot machine is one of popular gaming systems in the casino. In this paper, we present our design and implementation of protocol analysis system for SAS 6.0 protocol. Slot machine accounting system (SAS) is an international standards protocol and provides auditing, management, and additional service for slot machines. Our protocol analysis system design experience provide in-depth understanding on slot machine and its accounting requirement than a simple conceptual introduction of protocol. Also, the key difficulties of SAS protocol implementation and performance requirement is examined. Our system successfully works in small portable embedded system and showed its benefits, showing benefits for debugging and reverse-engineer a real work problem with commercial system. The engine of the analysis software will be the base of real SMIB (slot machine interface board) system for commercial use.