The user activates precedence calls by dialing a code on a per call basis.

If the originating user is not authorized for the dialed precedence level or for protected calls, the call attempt will be rejected, the user will be connected to Unauthorized Precedence Announcement and the message "nicht berechtigt"/"Not authorized" will be displayed on the optiPoint/OpenStage/CP400/CP600 device.

If the called MLPP subscriber is busy with a call of the same or higher precedence level or with a call from a different service domain, the originating user will be connected to Blocked Precedence Announcement and the message "bitte wiederholen"/"Please try later" will be displayed on the optiPoint/OpenStage/CP400/CP600 device.

If the called MLPP subscriber is idle, the calling station will receive precedence ringback tone and message "PRECEDENCE CALL" on the display while the called subscriber is ringing. After 4 seconds or when the called subscriber answers the call, the calling station will show the MLPP level in addition to the existing informations (called number, name), if administered.

If the called MLPP subscriber is busy with a call of the same or higher precedence level and call waiting for the called party is activated, the originating user will receive precedence ringback tone.

If the called MLPP subscriber is assigned as non-preemptible, the calling party will receive "geschuetzt/Protected" and Busy Not Equipped Announcement.

If the precedence call reaches an attendant queue, the user will be connected to Attendant Queue Announcement.

If the originating user originates a precedence call to a nonexistent number, the user will be connected to Vacant Code Announcement.

If technical problems make origination of a precedence call impossible, the user will be connected to Isolated Code Announcement.

In case of the DSN Hotline, the user activates the hotline calls by initiating a service request (usually hook-off). The call receives a precedence level automatically, administered earlier. If the called subscriber has a configured Black/White list, it will be checked to see whether the present call is allowed. If not, the originating user will not be connected to the Announcement and the message "bitte wiederholen"/"Please try later" will be displayed on the optiPoint/OpenStage/CP400/CP600 device. In other cases, the procedure is as for simple MLPP calls.