Open Source & VOIP Developer with 15years of extensive experience. - OpenSIP, PBX, SMS, MMS, Fax , Telephony, VOIP applications (Android & iOS) - Asterisk (setup & configuration) - Asterisk API creation and implementation - VOIP billing system - CRM integration with VOIP system - SIP Trunk configuration, troubleshoot and fixing - FreePBX installation and configuration - SMPP (SMS) to Asterisk transfer - SMS billing system (Prepaid service with SMS rates defined according to Prefix) - Android & iOS application (VOIP, Telephony, Instant messaging, File sharing, SMS)