VoIP phone service (Voice over IP) also known as digital phone service, digital telephony, or broadband phone) replaces your phone line with a high-speed Internet connection. It's that simple. While traditional telephone service compresses your voice into a frequency on a wire, VoIP compresses the sound of your voice into packets of data. In milliseconds, these data packets are sent over the Internet. When the data reaches the final destination, it is converted back to sound. If use VoIP to call someone on the traditional phone network (the PSTN or Public Switched Telephone Network), the VoIP call is converted to sound once it reaches the network and the call is routed normally. The difference is that you've paid a lot less for that call.
If you're a visual learner, the diagram to the right will show you how VoIP calls are routed using RateTel's sip trunking service. In most cases you have some sort of telephony solution at your location. It may or may not be VoIP ready, but in any case RateTel can provide a solution to connect your equipment to our sip trunking service through your internet connection.