On-call time is the period during which the worker, without being required to be directly present at the workplace, is required to be present for the purposes of the establishment or service at a place inside or outside the establishment determined by the employer in order to be able to start work immediately or as soon as possible if necessary. This form of on-call service must be distinguished from the readiness to be present, known in Germany as the “Arbeitsbereitschaft” (readiness to work), and the on-call service. (Source: https://de.wikipedia.org/wiki/Bereitschaftsdienst)