工作技能: 1. Familiar with networking protocols. 2. Familiar with software development environment on Ubuntu and MS-Windows. 3. Familiar with Embedded Linux (FreeRTOS, OpenRTOS) and hardware device driver. 4. Familiar with VoIP technology (SIP/SDP, RTP over TCP/UDP, Call features, Voice/Video Compression format). 5. Familiar with IP-PBX Cloud Service technology is Preferred