Good day,
Applicable skills are:
Expert skill/knowledge in Asterisk PBX, Freeswitch, A2Billing, Kamailio, Elastix and Kazoo
Expert skill/knowledge in SIPml5, Websockets and RESTFUL systems
Expert skill/knowledge in MySql, PHP, Python, C++, Ruby, Erlang
Expert skill/knowledge in Linux OS
Expert skill/knowledge in ffmpeg and sox
Feel free to contact me at anytime.