Dears,
I am an expert in establishing such set ups. I specialize in VOIP, Asterisk Dialplan programming, IVRs, Call Termination and Billing, Call Center Setups with predictive dialing, SMS solutions, Telecom Billing, Cisco based Networks for Voice, Linux Servers Administration and Engineering.
Here is the value that I can add to my work,
1. I can offer your free 1 month support
2. Custom installations and device configurations such as GSM gateways, Quintums, Cisco Voice Gateways and switches.
3. Asterisk or any other PBX integration along with open source A2Billing
4. Optimize your network for voice.
5. Email and SMS notifications with calls/balance threshold.
I can develop many custom apps for you based upon asterisk and integrate them with other platforms.