This function is overridden by DND and or Follow Me if applied. It overrides Forward on Busy and Forward on No Answer.
The destination can be any number that the user can dial. If external and Inhibit Off-Switch Transfers is applied, the caller is directed to voicemail if available, otherwise they receive busy tone.
The destination is rung using the forwarding user's No Answer Time. If this expires, the call goes to voicemail is available. Otherwise the call continues to ring at the destination. Calls to an external destination sent on trunks that do not signal their state, for example analog loop start trunks, are assumed to have been answered.
When enabled, the phone can still be used to make calls. An D is displayed on DS phones and normal dial tone is replaced by system locale specific alternate dial tone unless secondary dial tone is triggered.