Hi, I operate my own A2Billing server (customized) as a calling card platform for a private phone network covering the world. I have been a VOIP consultant since 1998 setting up Asterisk and also other terminations using Quantum, AudioCodes, Linksys/SPA, etc. I also build PBXs in Asterisk. I also have setup Asterisk PRI ro GSM phone companies.I also build GSM/SIM switching, PSTN/GM gateways, etc. Please see the PM. I am an IT, Electronics, Comunications expert!