This Court makes it clear that the hours of on-call time for an employer must be qualified as working time, since the person who is in this situation must be able to answer a call or provide a service to his company, and therefore does not have the freedom to dedicate himself fully to other activities.
From all this it follows that a person who intends to combine a second job during his on-call periods would have a difficult time, since these times are considered working time, and therefore it would be like doing two jobs at the same time.
This whole issue is given by the controversy of a firefighter from the city of Dublin, who combined his on-call periods with a second job which is driving his own taxi, claiming that his on-call time was 24 hours a day, 7 days a week, and that they were not recognized by Dublin City Council, which is the body he works for.
All these controversies about whether we are talking about "effective working time" or not can be resolved by recording the working day, regardless of what type of period is being traced.