Asterisk is complete VoIP software and runs on Linux operating system; it has all the features one would expect from an IP-PBX system. It has a capability to do Voice over IP and can interoperate with almost all standard telephony equipment using low cost hardware. It also provides other useful features such as Voicemail services Directory, Call conferencing, IVR and call waiting or queuing, three way calling, caller Id services and many more, this is most commonly called Unified communications.

With unified communications (UC), workers are no longer location-dependent and can work flexibly from home, whilst on the move or travelling abroad. This is made possible because all your resources including phone and email communications are accessible via your PC. As long as you have sufficient broadband then calls can be made and transferred to you, just like any other office telephone extension. As a result employees can move between different tasks easily, share data, access a conference call, send an instant message or even take a phone call all in real time. Holding on to valuable staff is important and with UC it becomes more practical to offer more flexible ways of working.

The asterisk has become one of the most popular open source software for delivering such solutions, GMSVoIP has incorporated this open source software with a dedicated virtual private server (VPS) as a complete asterisk based IP-PBX solutions, it is ready to use box with dedicated IP for each server.