Cisco TelePresence Administrator's Manual page 154

Dial plan and call processing
For example, Example Inc has the domain of example.com. The endpoint at reception has the alias
reception@example.com. They configure their VCS with a fallback alias of
reception@example.com. This means that any calls made directly to example.com (that is, without
being prefixed by an alias), are forwarded to reception@example.com, where the receptionist can
answer the call and direct it appropriately.
Cisco VCS Administrator Guide (X7.1) Page 154 of 479