ZD1211 is a compact, low power, high security and high performance solution for versatile WLAN applications. ZD1211 integrates WLAN MAC controller, base-band processor and USB 2.0 interface in single chip. The integrated USB 2.0 controller reduces the cost and design complexity. No extra memory device is needed. It can fit into small PCB form factor. There is Micro-Controller inside the chip. This allows the flexibility to software change the operation scenario to adapt in USB or WLAN compatibility issues. Integrated standard compliant hardware security engine to improve the performance in security mode. The hardware engine includes the WEP64, WEP128, WEP256, AES-CCM, TKIP that comply Wi-Fi and IEEE 802.11 defined standards.