Thank you invitation.
I read your requirement and based on that I think I can complete your tasks.
I have practical and relevant experience in the following area of VoIP :
* Asterisk,FreePBX,FreeSwitch,OpenSips customisations.
* Asterisk/OpenSips Development (PHPAGI,Bash Scripting,C module).
* IVR Solutions.
* Zaptle/DAHDI, LibPRI
* Linphone, Siphone, Quickblox customisation.