A call barrier secures a level crossing that is rarely used by road users, is usually located in a remote area and often cannot be seen by the responsible barrier attendant. The barriers are always closed and are only opened when necessary - if this can be done safely (see § 11 (17) EBO).
If a road user wants to pass through such a level crossing, he reports to the barrier attendant on duty via an intercom. The barrier attendant then opens the barrier - after possibly consulting the dispatchers responsible for the track section to the left or right of the crossing - if the train traffic allows it or announces the opening via the intercom. Since he cannot usually see the level crossing, the user is asked to report the evacuation to the attendant. In exceptional cases, the attendant may listen to the noises at the level crossing via the intercom and then close the barriers again. Before closing the barriers, he announces the closing via the intercom. Rarely, one or more cameras are installed to ensure greater security.