"With this tutorial, you'll learn how to configure a SIP extension that uses VoIP service with Teitco.com. We recommend using Zoiper for its user-friendly features to make and receive calls. If you require the G729 Codec to compress calls in low-signal situations, consider purchasing it. For background call ringing, you'll need the Pro version, but the configuration process remains the same as shown in the video."
TEITCO.com
