We have over 10 years of experience on VOIP technology. Worked on numerous Asterisk/VOIP projects. You can check my profile on https://www.freelancer.com/u/xuniltech.html
Specializes on
AGI/Asterisk Dialplan customizations. A2billing for asterisk billing. Vicidial Call Center Suite. Freepbx as Software PBX.
CRM like vtiger,SugarCRM integration with asterisk
Enterprise mailing with SPAM/Virus Scanning. Bulk Mailing.
Linux WebServers/Reverse Proxy like Varnish/Nginx/Apache
Proxy Servers: Squid with SSL interception/WCCP Client, etc.
Data Center/Cloud Services like Amazon AWS/Rackspace/Digital Ocean/Softlayer Servers
Control Panels like WHM/Cpanel, Plesk, Ispconfig, Webmin, Virtualmin, etc.
PHP-MySQL and HTML/CSS/JQuery Coding
Lets discuss the asterisk + a2b requirements and finish this project