Asterisk VoIP FreePBX 3CX FreeSwith Issabel SIP FusionPBX PBX Kamailio VoIP Asterisk, 3CX, Issabel, Elastix, FreePBX, FreeSWITCH, FusionPBX, Kamailio, OpenSIPS, OpenSER, FXO, FXS, E1, T1 SS7 ISDN - my main job. Skilled network administrator with 25 years of practice. More than 500 PBX installed, more than 200 VOIP projects released. Asterisk administrator, with 10 years of providing Asterisk-based solutions