RFA - Mobile Twinning Licenses

Added in IP Office 3.1, twinning allows calls to a user main extension number to alert at both that extension and a secondary extension. Though not restricted to DECT, this feature is aimed primarily at users who have both a desk phone and a wireless extension. Calls from the secondary twinned extension are presented as if from the users main extension. Presentation of call waiting and busy is based on whether either of the twinned extensions is in use.