Connect Directly to a voicemail box will allow an internal VoIP user to directly call a voicemail box greeting. This will allow you to call someone's voicemail and leave them a message without ringing their phone and waiting for voicemail to pickup. It will also allow you to transfer a caller to someone's voicemail box if you know they aren't available.
The dialing procedure is very easy, just dial * * and the 5 digit number. For example, if someone calls Becky and then decides they want to talk to me but I'm not in the office, Becky can simply: