...
The standard attendant "Operator" is defined as shown below but can also be easily customized. In particular, the default extension can be changed based on your internal dial plan. If you use a 3 digit internal dial plan, the auto-attendant extension should also be three digits. The Name is just an identifier for the auto-attendant and does not represent a User ID that can be dialed. The default auto-attendant defines three for different prompts: Repeat Prompt, Voicemail Login, Operator, and Dial by Name. Additional prompts available include: Disconnect, Auto-Attendant, Go to Extension, and Voicemail Deposit. In particular, the Auto-Attendant prompt allows you to cascade different auto-attendants. Voicemail Deposit allows a caller to deposit a voicemail message for a user without first ringing the user's extension number.
...