you have to call the balls that hit the line or go out when the ref can't see
There is no umpire in volleyball! There is an R1, otherwise known as an up ref who calls all the rules.
Coach or umpire
a volleyball a net two teams and a umpire and a crowed and a uniform
Haha, You said Duties!
The umpire assists the referee.
umpire scorer referee
a umpire is in baseball and a referee is in other sports such as football (american), Soccer, volleyball etc..,