Your service engineer can deactivate the display of your phone number and name on the called party's display for external outgoing calls. You can also activate and deactivate the phone number display on your own handset yourself. 

Deactivating the phone number display

Press the Talk key. 

Call the system menu. 

Select and confirm the menu item. 

Press the On-hook key to end the process. 

Activating the phone number display

Press the Talk key. 

Call the system menu. 

Select and confirm the menu item. 

Press the On-hook key to end the process.