Many of you have heard of Voice Over IP (VoIP). In the commercial world, providers are right now using an acronym you will probably hear more about: S-I-P (pronounced "sip"). In function and purpose, a "SIP" (Session Initiation Protocol) Trunk is simply a phone line (and number) that routes over your data connection. Many of us are familiar with Vonage for residential use. SIP trunking could be thought of as the commercial version. Instead of purchasing "lines", you purchase "talk paths" based on the number of concurrent calls you expect. The advantages of SIP are: easy transition into VoIP, quick provisioning (!), low long distance and international rates, and very scaleable. There are 2 implementations of SIP trunking: if you have a SIP-compliant PBX (AltiGen), then you will just need to be provided with an IP address! If you have a traditional PBX, then you will need to have installed an adapter and you can keep your existing hardware.
