The Feature allows you to freely map applications and features to star codes.
See main article Feature Map
The operator is a special short-cut used when you enter 0 during voicemail playback/retrieval and dial-by-name searches. It can be a group, queue, extension, channel, IVR or even a conference room.
If allow 0 to reach operator directly is checked any user can dial 0 from their phone to reach the pre-set extension (or application). Be careful when using this option and make sure your phone dialplan supports dialing 0 as an extension.
If you wish to have an operator option/digit in a custom IVR simply set it up as you would with any other digit/function.