System information

callers to be transferred to extensions, and it is built into most proprietary voicemail
systems—but IVR can be so much more.
IVR systems are generally very expensive, not only to purchase, but also to configure.
A custom IVR system will usually require connectivity to an external database or ap-
plication. Asterisk is arguably the perfect IVR, as it embraces the concepts of connec-
tivity to databases and applications at its deepest level.
Figure 27-2. Find-me-follow-me
Figure 27-3. VoIP-enabling a legacy PBX
584 | Chapter 27: Asterisk: A Future for Telephony