Multiple subscriber numbers are phone numbers belonging to an ISDN multiple device line. They are used for the directed addressing of terminals, for example when a fax machine has a separate number. Before selecting an external connection, you can directly assign a configured multiple subscriber number. This then appears on the called party's display. 

This function can also be called by entering the code (). 

Press the Talk key. 

Call the system menu. 

Select and confirm the menu item.  

Select and confirm the menu item. 

Enter the required multiple subscriber number. 

Enter the required external phone number. The phone number is dialled.