That’s usually comp for simply being on-call - all agreements I’ve ever had includes increased compensation for actual on-call work a.k.a overtime compensation.
3. Call-out
Call-out means work for which the employee is called back after regular working
hours and after having left the workplace.
3.1. At least one hour’s salary and a call-out pay shall be paid as follows:
a) If the employee was called after regular working hours or on the employ-
ee’s day off but before 9.00 pm, the call-out pay is equivalent to 2 hours’
salary.
b) If the employee was called between 9:00 pm and 6:00 am, the call-out
pay is equivalent to 3 hours’ salary.
3.2. If the work in case b) above represents daily overtime, the overtime com-
pensation for call-out work done as overtime work is immediately 100%.