VoIP is a rapidly growing area with great market potential. To promote it for both commercial and research purposes, we are developing an efficient voice access system based on state-of-art Motorola communication techniques. It is composed of a communication subsystems, a voice interface, and an information agent. Implementation of the high performance communication system is described in this paper. It is a gateway system integrating a PBX and a VoIP module. All components that H.323 defined to support VoIP are implemented in the VoIP module, currently in a simplified manner. As an embedded system, it features realtimeness and task distributiveness. A number of additional techniques are used to improve the communication performance, including noise suppression, zero copy, and buffer structure optimization. When integrated and refined in interoperability, the system will readily serve as a product. Keywords VoIP, gateway, gatekeeper, communication common platform, embedded system, voice processing, H.323. 1