One of the most popular implementations of Asterisk is in the form of a VoIP gateway. It is frequently used in conjunction with Digium telephony interface cards to connect legacy PBX systems with VoIP services or, conversely, to link IP PBX systems to legacy PSTN connections. Asterisk's powerful multi-protocol call processing engine supports virtually every PSTN and VoIP protocol and technology making it possible to connect at a fraction of the cost of traditional gateway systems.
- Support for the most common protocols including:
IP Protocols PSTN Protocols SIP Analog Skype T1/E1/J1 IAX2 ISDN-PRI H.323 ISDN-BRI MFC/R2 SS7
- Dynamic call routing for cost savings ("least cost routing") or for redundancy/fail-over.
- Call data forwarding and manipulation across various technologies.
- Inexpensive solution based on commodity computer hardware.
- Based on stable and widely tested Linux operating system.
- Extend the life of legacy investments by adding IP telephony capabilities and services.
- Save money on long distance and international charges by using low cost VoIP services.
- Save money on toll charges by implementing private connections over the corporate WAN.
- Rapid return on investment (ROI) – generally less than 12 months.