Dial plan
Proceed as follows:
Using the Configuration Manager ( Overviews > Dial plan page)
The phone numbering plan shows all of the internal numbers already created and any additional numbers that have been taken from the internal numbering plan:
Subscriber number
Group numbers
Voice mailbox numbers
Fax box numbers
Phone numbers for door terminals and audio outputs
Short-code dialling numbers
Emergency and service numbers
Exchange line access numbers (account numbers) for VoIP accounts
Exchange line access number of the PBX
Automatic receptions
Call on hold
Internal CAPI dial-in number
Macro short-code number
The internal numbering plan of the PBX permits the allocation of 2 to 4-digit phone numbers in the 10-9999 range. Double allocation of a number is not possible.
Using numbers with few digits (two or three-digit numbers) inevitably restricts the possible supply of numbers requiring more digits. For  example, if the phone number 12 is assigned, the phone numbers 120-129 and 1200-1299 are no longer available.
* Note: For some functions a 3-digit maximum phone numbers can be assigned because the last position is needed for the function (e.g. door terminal numbers, phone numbers for call parking).
* Note: The exchange line access number on the PBX is 0 in the factory settings; however, this can be changed (Public switched tel. networks > Exchange line request). Note that changing the exchange line access number restricts the number plan.
* Note: The overview can be viewed and printed ( Overviews > Dial plan ) in the Configuration Manager by opening the page Printing.
* Note: The phone numbers can be shown in the Total overview or Grouped by type .
* Note: In the overview Grouped by type on