2011/48 Inactive stand-by periods can be compensated differently from active working hours (BE)
Remuneration for stand-by periods, during which an employee is simply asked to be available by phone in order to answer urgent calls, without the obligation to be at a specific location or to perform his habitual tasks, need not be equivalent to the remuneration for active working hours.
Cour de cassation (Belgian Supreme Court), 2011-06-06